NOAA Technical Memorandum NMFS-NE-172

Variability

of Temperature and Salinity

in the Middle Atlantic Bight

and Gulf of Maine

Based on Data Collected

as Part of the MARMAP

Ships of Opportunity Program,

1978-2001

U. S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Northeast Fisheries Science Center

Woods Hole, Massachusetts

March 2003
155. Food of Northwest Atlantic Fishes and Two Common Species of Squid. By Ray E. Bowman, Charles E. Stillwell, William

L. Michaels, and Marvin D. Grosslein. January 2000. xiv + 138 p., 1 fig., 7 tables, 2 app. NTIS Access. No. PB2000-106735.

156. Proceedings of the Summer Flounder Aging Workshop, 1-2 February 1999, Woods Hole, Massachusetts. By George

R. Bolz, James Patrick Monaghan, Jr., Kathy L. Lang, Randall W. Gregory, and Jay M. Burnett. May 2000. v + 15 p., 5 figs.,

5 tables. NTIS Access. No. PB2000-107403.

157. Contaminant Levels in Muscle of Four Species of Recreational Fish from the New York Bight Apex. By Ashok D.

Deshpande, Andrew F.J. Draxler, Vincent S. Zdanowicz, Mary E. Schrock, Anthony J. Paulson, Thomas W. Finneran, Beth

L. Sharack, Kathy Corbo, Linda Arlen, Elizabeth A. Leimburg, Bruce W. Dockum, Robert A. Pikanowski, Brian May, and

Lisa B. Rosman. June 2000. xxii + 99 p., 6 figs., 80 tables, 3 app., glossary. NTIS Access. No. PB2001-107346.

158. A Framework for Monitoring and Assessing Socioeconomics and Governance of Large Marine Ecosystems. By

Jon G. Sutinen, editor, with contributors (listed alphabetically) Patricia Clay, Christopher L. Dyer, Steven F. Edwards, John

Gates, Tom A. Grigalunas, Timothy Hennessey, Lawrence Juda, Andrew W. Kitts, Philip N. Logan, John J. Poggie, Jr.,

Barbara Pollard Rountree, Scott R. Steinback, Eric M. Thunberg, Harold F. Upton, and John B. Walden. August 2000. v

+ 32 p., 4 figs., 1 table, glossary. NTIS Access. No. PB2001-106847.

159. An Overview and History of the Food Web Dynamics Program of the Northeast Fisheries Science Center, Woods

Hole, Massachusetts. By Jason S. Link and Frank P. Almeida. October 2000. iv + 60 p., 20 figs., 18 tables, 1 app. NTIS

Access. No. PB2001-103996.

160. Measuring Technical Efficiency and Capacity in Fisheries by Data Envelopment Analysis Using the General

Algebraic Modeling System (GAMS): A Workbook. By John B. Walden and James E. Kirkley. October 2000. iii + 15 p.,

9 figs., 5 tables. NTIS Access. No. PB2001-106502.

161. Demersal Fish and American Lobster Diets in the Lower Hudson - Raritan Estuary. By Frank W. Steimle, Robert

A. Pikanowski, Donald G. McMillan, Christine A. Zetlin, and Stuart J. Wilk. November 2000. vii + 106 p., 24 figs., 51 tables.

NTIS Access. No. PB2002-105456.

162. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2000. Edited by Gordon T. Waring, Janeen

M. Quintal, and Steven L. Swartz, with contributions from (listed alphabetically) Neilo B. Barros, Phillip J. Clapham, Timothy

V.N. Cole, Carol P. Fairfield, Larry J. Hansen, Keith D. Mullin, Daniel K. Odell, Debra L. Palka, Marjorie C. Rossman, U.S.

Fish and Wildlife Service, Randall S. Wells, and Cynthia Yeung. November 2000. ix + 303 p., 43 figs., 55 tables, 3 app. NTIS

Access. No. PB2001-104091.

163. Essential Fish Habitat Source Document: Red Deepsea Crab, Chaceon (Geryon) quinquedens, Life History and

Habitat Characteristics. By Frank W. Steimle, Christine A. Zetlin, and Sukwoo Chang. January 2001. v + 27 p., 8 figs.,

1 table. NTIS Access. No. PB2001-103542.

164. An Overview of the Social and Economic Survey Administered during Round II of the Northeast Multispecies Fishery

Disaster Assistance Program. By Julia Olson and Patricia M. Clay. December 2001. v + 69 p., 3 figs., 18 tables, 2 app.

NTIS Access. No. PB2002-105406.

165. A Baseline Socioeconomic Study of Massachusetts’ Marine Recreational Fisheries. By Ronald J. Salz, David K.

Loomis, Michael R. Ross, and Scott R. Steinback. December 2001. viii + 129 p., 1 fig., 81 tables, 4 app. NTIS Access. No.

PB2002-108348.

166. Report on the Third Northwest Atlantic Herring Acoustic Workshop, University of Maine Darling Marine Center,

Walpole, Maine, March 13-14, 2001. By William L. Michaels, editor and coconvenor, and Philip Yund, coconvenor.

December 2001. iv + 18 p., 14 figs., 2 app. NTIS Access. No. PB2003-101556.

Recent Issues in This Series:
U. S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

National Oceanic and Atmospheric Administration

Vice Admiral Conrad C. Lautenbacher, Jr., USN (ret.), Administrator

National Marine Fisheries Service

William T. Hogarth, Assistant Administrator for Fisheries

Northeast Fisheries Science Center

Woods Hole, Massachusetts

March 2003

Jack W. Jossi1,2 and Robert L. Benway1,3

Postal Addresses: 1National Marine Fisheries Serv., Narragansett Lab., 28 Tarzwell Dr., Narragansett, RI 02882

E-Mail Addresses: 2

Jack.Jossi@noaa.gov; 3Robert.L.Benway@noaa.gov

This series represents a secondary level of scientific publishing. All issues employ

thorough internal scientific review; some issues employ external scientific review.

Reviews are -- by design -- transparent collegial reviews, not anonymous peer

reviews. All issues may be cited in formal scientific communications.

NOAA Technical Memorandum NMFS-NE-172

Variability of Temperature and Salinity

in the Middle Atlantic Bight and Gulf of Maine

Based on Data Collected as Part of the

MARMAP Ships of Opportunity Program,

1978-2001
Editorial Notes

Statistical Terms: The NEFSC Editorial Office’s policy on the use of statistical terms in all technical communications is

generally to follow the International Standards Organization’s handbook of statistical methods (i.e., ISO 1981a).

Internet Availability: This issue of the NOAA Technical Memorandum NMFS-NE series is being copublished, i.e., as

both a paper and Web document. The Web document, which will be in HTML (and thus searchable) and PDF formats,

can be accessed at: http://www.nefsc.noaa.gov/nefsc/publications/.

a

ISO [International Organization for Standardization]. 1981. ISO standards handbook 3: statistical methods. 2nd ed. Geneva, Switzerland:

ISO; 449 p.
Page iii

Contents

Abstract ................................................................................................................................................................................vi

Introduction ........................................................................................................................................................................... 1

Materials and Methods .......................................................................................................................................................... 1

Sampling Locations....................................................................................................................................................... 1

Data Collection ............................................................................................................................................................. 1

Temporal Scales of Sampling ........................................................................................................................................ 1

Spatial Scales of Sampling ............................................................................................................................................ 2

Data Processing ............................................................................................................................................................ 2

Gridding ........................................................................................................................................................................ 2

Time Plots ..................................................................................................................................................................... 3

Results ................................................................................................................................................................................... 3

Baseline Conditions during 1978-90 .............................................................................................................................. 4

Annual Conditions during 1998-2001 ............................................................................................................................ 5

Time Plots of Anomalies for the 1978-2001 Time Series .............................................................................................. 10

Discussion ........................................................................................................................................................................... 13

Acknowledgments ............................................................................................................................................................... 13

References Cited .................................................................................................................................................................. 13

Tables

Table 1. Equations for calculating depth during an expendable bathythermograph deployment ................................ 15

Table 2. Gridding methods and elliptical search radii for both sampling routes and grid types................................... 15

Table 3 Summary statistics for gridding residuals for the Middle Atlantic Bight and Gulf of Maine .......................... 16

Table 4. Annual mean values and anomalies of surface temperatures and salinities and bottom temperatures for

the entire Middle Atlantic Bight transect from 1991 through 2001 ................................................................. 17

Table 5. Annual mean values and anomalies of surface temperatures and salinities and bottom temperatures for

the entire Gulf of Maine transect from 1991 through 1997 .............................................................................. 18

Figures

Figure 1a. The Middle Atlantic Bight - Route MB polygon within which monitoring transects occurred,

showing reference distances, location of Ambrose Tower, and major geographical features ....................... 19

Figure 1b. The Gulf of Maine - Route MC polygon within which monitoring transects occurred, showing

reference distances and major geographical features ..................................................................................... 20

Figure 2. Distribution of residuals from the base-period grids for the years 1978 through 1990 ................................... 21

Figure 3. Distribution of residuals from the single-year grids composited over the years 1991 through 2001 .............. 22

Figure 4. Mean surface temperature conditions along the Middle Atlantic Bight route during 1978-90....................... 23

Figure 5. Mean surface salinity conditions along the Middle Atlantic Bight route during 1978-90 .............................. 24

Figure 6. Mean bottom temperature conditions along the Middle Atlantic Bight route during 1978-90 ....................... 25

Figure 7. Mean surface temperature conditions along the Gulf of Maine route during 1978-90 ................................... 26

Figure 8. Mean surface salinity conditions along the Gulf of Maine route during 1978-90 ........................................... 27

Figure 9. Mean bottom temperature conditions along the Gulf of Maine route during 1978-90 .................................... 28

Figure 10. Surface temperature conditions along the Middle Atlantic Bight transect during 1991 ................................. 29

Figure 11. Surface salinity conditions along the Middle Atlantic Bight transect during 1991 ........................................ 30

Figure 12. Bottom temperature conditions along the Middle Atlantic Bight transect during 1991 ................................. 31

Figure 13. Surface temperature conditions along the Gulf of Maine transect during 1991 .............................................. 32

Figure 14. Surface salinity conditions along the Gulf of Maine transect during 1991 ..................................................... 33

Figure 15. Bottom temperature conditions along the Gulf of Maine transect during 1991 .............................................. 34

Figure 16. Surface temperature conditions along the Middle Atlantic Bight transect during 1992 ................................. 35

Figure 17. Surface salinity conditions along the Middle Atlantic Bight transect during 1992 ........................................ 36

Figure 18. Bottom temperature conditions along the Middle Atlantic Bight transect during 1992 ................................. 37

Figure 19. Surface temperature conditions along the Gulf of Maine transect during 1992 .............................................. 38
Page iv

Figure 20. Surface salinity conditions along the Gulf of Maine transect during 1992 ..................................................... 39

Figure 21. Bottom temperature conditions along the Gulf of Maine transect during 1992 .............................................. 40

Figure 22. Surface temperature conditions along the Middle Atlantic Bight transect during 1993 ................................. 41

Figure 23. Surface salinity conditions along the Middle Atlantic Bight transect during 1993 ........................................ 42

Figure 24. Bottom temperature conditions along the Middle Atlantic Bight transect during 1993 ................................. 43

Figure 25. Surface temperature conditions along the Gulf of Maine transect during 1993 .............................................. 44

Figure 26. Surface salinity conditions along the Gulf of Maine transect during 1993 ..................................................... 45

Figure 27. Bottom temperature conditions along the Gulf of Maine transect during 1993 .............................................. 46

Figure 28. Surface temperature conditions along the Middle Atlantic Bight transect during 1994 ................................. 47

Figure 29. Surface salinity conditions along the Middle Atlantic Bight transect during 1994 ........................................ 48

Figure 30. Bottom temperature conditions along the Middle Atlantic Bight transect during 1994 ................................. 49

Figure 31. Surface temperature conditions along the Gulf of Maine transect during 1994 .............................................. 50

Figure 32. Bottom temperature conditions along the Gulf of Maine transect during 1994 .............................................. 51

Figure 33. Surface temperature conditions along the Middle Atlantic Bight transect during 1995 ................................. 52

Figure 34. Surface salinity conditions along the Middle Atlantic Bight transect during 1995 ........................................ 53

Figure 35. Bottom temperature conditions along the Middle Atlantic Bight transect during 1995 ................................. 54

Figure 36. Surface temperature conditions along the Gulf of Maine transect during 1995 .............................................. 55

Figure 37. Bottom temperature conditions along the Gulf of Maine transect during 1995 .............................................. 56

Figure 38. Surface temperature conditions along the Middle Atlantic Bight transect during 1996 ................................. 57

Figure 39. Surface salinity conditions along the Middle Atlantic Bight transect during 1996 ........................................ 58

Figure 40. Bottom temperature conditions along the Middle Atlantic Bight transect during 1996 ................................. 59

Figure 41. Surface temperature conditions along the Gulf of Maine transect during 1996 .............................................. 60

Figure 42. Bottom temperature conditions along the Gulf of Maine transect during 1996 .............................................. 61

Figure 43. Surface temperature conditions along the Middle Atlantic Bight transect during 1997 ................................. 62

Figure 44. Surface salinity conditions along the Middle Atlantic Bight transect during 1997 ........................................ 63

Figure 45. Bottom temperature conditions along the Middle Atlantic Bight transect during 1997 ................................. 64

Figure 46. Surface temperature conditions along the Gulf of Maine transect during 1997 .............................................. 65

Figure 47. Bottom temperature conditions along the Gulf of Maine transect during 1997 .............................................. 66

Figure 48. Surface temperature conditions along the Middle Atlantic Bight transect during 1998 ................................. 67

Figure 49. Surface salinity conditions along the Middle Atlantic Bight transect during 1998 ........................................ 68

Figure 50. Bottom temperature conditions along the Middle Atlantic Bight transect during 1998 ................................. 69

Figure 51. Surface temperature conditions along the Gulf of Maine transect during 1998 .............................................. 70

Figure 52. Bottom temperature conditions along the Gulf of Maine transect during 1998 .............................................. 71

Figure 53. Surface temperature conditions along the Middle Atlantic Bight transect during 1999 ................................. 72

Figure 54. NOAA 14 and NOAA 15 Advanced Very High Resolution Radiometer satellite imagery, composited

using warmest pixel, for: (A) November 12-14, 1999; and (B) December 5, 1999 ............................................ 73

Figure 55. Surface salinity conditions along the Middle Atlantic Bight transect during 1999 ........................................ 74

Figure 56. Bottom temperature conditions along the Middle Atlantic Bight transect during 1999 ................................. 75

Figure 57. Surface temperature conditions along the Gulf of Maine transect during 1999 .............................................. 76

Figure 58. Bottom temperature conditions along the Gulf of Maine transect during 1999 .............................................. 77

Figure 59. Surface temperature conditions along the Middle Atlantic Bight transect during 2000 ................................. 78

Figure 60. Surface salinity conditions along the Middle Atlantic Bight transect during 2000 ........................................ 79

Figure 61. Bottom temperature conditions along the Middle Atlantic Bight transect during 2000 ................................. 80

Figure 62. Surface temperature conditions along the Middle Atlantic Bight transect during 2001 ................................. 81

Figure 63. Surface salinity conditions along the Middle Atlantic Bight transect during 2001 ........................................ 82

Figure 64. Bottom temperature conditions along the Middle Atlantic Bight transect during 2001 ................................. 83

Figure 65. Surface temperature conditions along the Gulf of Maine transect during 2001 .............................................. 84

Figure 66. Bottom temperature conditions along the Gulf of Maine transect during 2001 .............................................. 85

Figure 67. Mean bottom depth along the transects based on monitoring survey data, 1978-90 ..................................... 86

Figure 68. Results of variable cluster analysis of standardized anomalies of sea surface temperatures and salinities

along the Gulf of Maine transect for the 1978-90 base period ........................................................................ 87

Figure 69. Time plots of standardized departures of surface temperature, surface salinity, and bottom temperature

from 1978-90 means at a transect location representing the Middle Atlantic Bight continental shelf

between New York and Bermuda .................................................................................................................... 88

Figure 70. Time plots of standardized departures of surface temperature, surface salinity, and bottom temperature

from 1978-90 means at a transect location representing Massachusetts Bay ................................................ 89
Page v

Figure 71. Time plots of standardized departures of surface temperature, surface salinity, and bottom temperature

from 1978-90 means at a transect location representing the western Gulf of Maine ....................................... 90

Figure 72. Time plots of standardized departures of surface temperature, surface salinity, and bottom temperature

from 1978-90 means at a transect location representing the eastern Gulf of Maine ........................................ 91

Figure 73. Time plots of standardized departures of surface temperature, surface salinity, and bottom temperature

from 1978-90 means at a transect location representing the western Scotian Shelf ........................................ 92

Acronyms

GOM = Gulf of Maine

MAB = Middle Atlantic Bight

MARMAP = Marine Resources Monitoring, Assessment, and Prediction Program

NAO = North Atlantic Oscillation

PSU = practical salinity unit

QC = quality control

SOOP = Ships of Opportunity Program

XBT = expendable bathythermograph
Page vi

ABSTRACT

Monitoring of the Middle Atlantic Bight (MAB) and Gulf of Maine (GOM) has been conducted by the Marine Resources

Monitoring, Assessment, and Prediction Program’s (MARMAP’s) Ships of Opportunity Program (SOOP) since the early

1970s. Portrayals of temporal and spatial patterns of surface and bottom temperature and surface salinity for SOOP transects

crossing these regions during 1991-2001, and time plots of anomalous conditions for spatially coherent sections of these

transects during the period 1978-2001, are presented. Annual transect averages and departures are presented for both

regions.

 Lowest average annual surface temperature in the MAB during 1978-2001 and in the GOM during 1978-97 (after which

coverage was insufficient) occurred in 1996, departing from baselines in both regions by an average of 1.1°C. Highest

average annual surface temperature during the same respective periods occurred in 1995 for the MAB, and in 1991 for the

GOM, departing from baselines by 1.3°C for the MAB, and by 0.4°C for the GOM. Three years of consistently low average

surface temperatures in the MAB ended in 1999, followed by two more years of positive departures.

 Surface salinities in the MAB had their lowest annual averages in 1998, departing from baselines by 1.1 practical salinity

units. Four years of consistently low surface salinities in the MAB ended in 2000.

Bottom temperatures in the MAB were lowest in 1994, averaging 1.4°C below the baseline. Bottom temperatures in the

GOM were lowest in 1997, averaging 0.5°C below the baseline. From 1999 through 2001, the MAB bottom temperatures were

consistently above the baseline, with the maximum departure for the entire period of record of 1.8°C in 1999.

The annual transect average data and the time plots reveal that the magnitude of departures from long-term means was

greater for all features and in all regions during the 1990s than during earlier years.
Page 1

INTRODUCTION

The Marine Resources Monitoring, Assessment, and

Prediction Program (MARMAP) Ships of Opportunity

Program (SOOP) has been consistently collecting temperature and salinity information between Massachusetts and

Cape Sable, Nova Scotia, and from New York City across

the continental shelf and slope towards Bermuda, since

1978. A history of the program and variations in surface

and bottom temperature and surface salinity through 1990

were summarized by Benway, Jossi, Thomas et al. (1993).

Included in the latter work were comparisons of time-space

conditions with 1978-90 baseline values. Since 1990,

annual summaries, in similar format, have appeared as

NAFO [Northwest Atl. Fish. Organ.] SCR [Sci. Counc. Res.]

Documents (Benway et al. 1992; Benway, Jossi, and

Griswold 1993; Benway and Jossi 1994, 1995, 1996, 1997,

1998; Benway 1998). However, these post-1990 annual

reports did not utilize the consistent baseline of the original

1978-90 summary. For that reason, it was decided to reanalyze the 1991-2001 data and produce a report

comparable with the first summary.

This report describes the common methods used

during 1978-2001, presents the 1978-90 baseline conditions

of surface and bottom temperature and surface salinity for

the Middle Atlantic Bight (MAB) and Gulf of Maine

(GOM), portrays the 1991-2001 values and their departures

from baseline conditions, and presents 1978-2001 time

plots of conditions for several spatially coherent sections

of the two transects.

MATERIALS AND METHODS

SAMPLING LOCATIONS

The track lines of the ships of opportunity varied on

different monthly occupations of a route. For consistency

among sampling efforts, two route polygons were

developed for analysis and portrayal of the data collected

in the two regions. These polygons (Figures 1a and 1b)

were based on composites of all sampling locations, such

that oceanographic features were assumed to vary along

the polygons’ long axes, but to vary insignificantly normal

to the long axes. Only data collected within the polygons

were included in analyses. A standard reference position

was chosen for each route from which the radial distance to

each sample location was calculated. These reference

positions were located at such distances beyond the

narrow ends of the polygons so that arcs passing through

the sample location had little curvature (see Figures 1a and

1b). The calculation also produced a reference distance

which was positive from North America seaward.

The MAB sampling (Figure 1a) originated at Ambrose

Tower (40°27.5’N, 73°49.6’W) and extended offshore

approximately 500 km towards Bermuda. This route is

termed MARMAP Route MB, and the corners of this

polygon are defined by the following geographic

positions: 40°34’N, 74°00’W; 40°20’N, 74°00’W; 38°30’N,

69°00’W; and 36°44’N, 70°30’W. Sampling generally

concluded within the Gulf Stream. Because of the Gulf

Stream’s varying position, not all sampling transects

traversed the entire polygon length. A transect along this

route typically passed through shelf, slope, and Gulf

Stream water masses, and often crossed a portion of Deep

Water Dumpsite 106. The major hydrographic features of

this region were summarized by Ingham (1982).

The GOM sampling extended from the Massachusetts

coast to Cape Sable, Nova Scotia (Figure 1b), for a distance

of approximately 452 km. This route is termed MARMAP

Route MC, and the corners of this polygon are defined by

the following geographic positions: 43°30’N, 71°00’W;

43°30’N, 65°37’W; 43°00’N, 65°37’W; and 42°00’N,

71°00’W. This polygon included the following geographic

regions of the GOM: Massachusetts Bay, Wilkinson

Basin, the central Gulf ledges, southern Jordan Basin,

Crowell Basin, and the western Scotian Shelf.

DATA COLLECTION

The sampling regimen at every station included

deployment of an expendable bathythermograph (XBT)

probe and concurrent collection of a sea-surface bucket

sample for temperature calibration and salinity determination. In both polygons, XBT’s were used to measure watercolumn temperatures down to a maximum depth of 500 m.

Stations were positioned on the basis of time intervals

rather than actual geographical locations. Sampling was at

least hourly in the MAB, and varied from every 1-2 hr in the

GOM. Prior to 1981, all data were collected utilizing

Sippican analog recorders, and traces were digitized.

Thereafter, data were recorded digitally.

Ship position, time of XBT deployment, and watercolumn depth (taken from a depth chart or fathometer) were

recorded in the computer and on a MARMAP log sheet.

Full details on SOOP operational procedures and theory are

available in Benway and Jossi (in review).

TEMPORAL SCALES OF SAMPLING

Monitoring of water temperature and salinity in the

MAB and GOM began in mid-year 1970. However, data

collected before 1978 were too incomplete for atlas

portrayal. In the MAB, one or two (occasionally three to

four) sampling cruises were conducted per month. By

comparison, there was one sampling cruise per month

carried out across the GOM. Although it was desirable to

sample during the first 2 wk of a month for logistical

reasons (i.e., being able to repeat sampling in case of

failure), sampling often occurred later in the month.

However, annual means of the variables measured on both

routes reveal no pattern or step change related to the

variation of sampling times. During 1986, no XBT’s were
Page 2

deployed in the GOM, so no bottom temperature data were

collected. Gulf of Maine surface salinity sampling ceased

after 1993.

SPATIAL SCALES OF SAMPLING

In the MAB, a typical transect began with the first

station at Ambrose Tower (40°27.5’N, 73°49.6’W; distance

from reference point = 17 km) (Figure 1a). Generally,

subsequent stations occurred about every hour (i.e., every

25-35 km depending on vessel speed) across the

continental shelf. Stations were spaced at 15-min (i.e., 7-

km) intervals near the continental shelf break. Thereafter

stations occurred each hour until the North Wall of the Gulf

Stream was reached. The first station when traveling from

Bermuda to New Jersey was at the Gulf Stream North Wall,

with sampling at the outbound intervals until reaching

Ambrose Tower. Surface water samples and water-column

temperature data were collected at each station.

In the GOM, sampling was initiated from either end of

the Route MC polygon until 1993. Thereafter, sampling

took place from Nova Scotia to Massachusetts (Figure 1b).

Surface water samples were collected every 1 or 2 hr (i.e.,

every 18 or 36 km), and water-column temperature profiles

were obtained no less than every 2 hr.

DATA PROCESSING

The depth of each XBT voltage reading was derived as

a function of time alone, using XBT descent equations

shown in Table 1.

The XBT voltage readings were converted to

temperatures in several steps. First, a Sippican system

MK-9 XBT Controller transmitted hexadecimal voltage

values (representing XBT thermistor measurements) to a

shipboard personal computer. Second, the XBT program

converted those hexadecimal voltage equivalents to

resistance, and then to temperature (°C), in the following

manner:

1. Convert hexadecimal value to decimal value.

2. Convert decimal value to (V) voltage (i.e., V = 10.0 ×

decimal value / 4096).

3. Convert (V) voltage to (R) resistance as measured in

ohms (i.e., R = (18094 - 1490.1) × V).

4. Convert (R) resistance to (T) temperature as measured

in°C (i.e., T = -273.15 + {1 / [A + (B × ln R) + C × (ln R)3

)]},

where: A = 1.29502 × 10-3, B = 2.34546 × 10-4, and C = 9.9434

× 10-8).

This logarithmic equation was first presented by Steinhart

and Hart (1968). The constants were determined

empirically from laboratory tests of XBT thermistors

(Georgi et al. 1980).

Quality control (QC) software was designed specifically for the digital data format established in 1981. For

each sampling station, QC plots of temperature versus

depth were produced, and all depth-temperature pairs were

listed. QC plots were used to determine water-column

depth, surface temperature, and bottom temperature, as

well as to delete inaccurate XBT drops. Water-column

depth was determined by comparing the log sheet depth

with any bottom impact marks on the QC plot. Surface

bucket temperatures were used to calibrate probe values.

Bottom temperatures were chosen from corresponding

probe bottom impact marks located on the analog graph

output.

Conductivity measurements of sea surface samples

were generated by use of a Guildline Model 8400a Autosal.

Conductivities were converted to salinity values using the

UNESCO standard equations of state (UNESCO 1981).

Time-distance checks were performed on all recorded

time and position data to eliminate erroneous log entries.

Analyses of the data revealed considerable temporal and

spatial variability for surface temperature, surface salinity,

and bottom temperature along both of the routes. As a

result, a time-space mapping technique was developed to

portray the data in a form that retained most of the original

detail, to show long-term means and variances, and to

determine departures from the means for individual years.

Further, the technique permitted the extraction of spatially

coherent time series and the analysis of relationships

among measured values.

GRIDDING

To overcome problems associated with irregular

sampling in both space and time, the data were subjected to

a gridding procedure. The design of the gridding method

was developed in part with other research at NOAA

Fisheries’ Narragansett Laboratory (Jossi et al. 1991;

Thomas 1992). From each irregularly spaced raw data

matrix, the gridding technique calculated a curved planar

surface using interpolated data values at regular, spatialtemporal grid points. Time-space grids of single-year

values, base-period (1978-90) mean values, standard

deviation values, and single-year data algebraic anomaly

and standardized anomaly values were produced. The

1978-90 period was selected as the base period to compare

the post-1990s’ results with those published for the 1970s

and 1980s (Benway, Jossi, Thomas et al. 1993).

Each grid was defined by route polygon reference

distance (range: 0-452 km) along the x-axis, time (range: 0-

365.25 days) along the y-axis, and sample scalar values

along the z-axis. For MAB bottom temperature data, the

grid values at greater than the 210-km reference distance

were converted to blanks due to the limits of the XBT

probe. All grids were constructed such that grid points

occurred at intervals of 17.38 km and 15.22 days, i.e., there

were 27 grid columns (26 divisions in x) along each

polygon, and 25 grid rows (24 divisions in y) for every year

or base period (Table 2).

Grid dimensions and techniques were chosen by

considering, in descending order of importance: 1) the
Page 3

closeness of fit between the actual data values and the

interpolated grid values as measured by the characteristics

of the residuals; 2) the average data coverage in time and

space; 3) the portrayed rates of change of the scalar values;

and 4) the intended use of final products. The statistical

characteristics of the residuals are reported in Table 3.

Distributions of the residuals from the base-period grids,

and of a composite of the residuals from the single-year

grids, are fairly symmetrical (Figures 2 and 3). One

exception is the residuals for route MB base-period bottom

temperatures, which although having a centered mean,

exhibited extreme skewness and kurtosis. This likely is due

to the very rapid depth change at the offshore limit of

sampling, and the resulting significant difference in depth

sampled (i.e., water temperatures measured) with small

changes of reference distance. None of the residual sets

satisfied the Kolomogorov D statistic for normality. An

inherent bias in this gridding technique is the de-emphasis

of extreme amplitudes in the raw data values. However, the

tails of the residual distributions (Figures 2 and 3) do not

show that this is a severe problem.

The remainder of this section will detail the sequence

of gridding steps applied to all data types. First, a baseperiod weighted mean grid, including all data collected

during 1978-90, was generated (Figures 4-9, panel A).

Second, the base-period grid surface, at the actual spatialtemporal location of each observation, was subtracted from

observed values to produce a data set of base-period

residuals (Figure 2). Calculation of these values assumed a

flat, rather than curved surface in each neighborhood.

Third, a weighted variance was found by squaring all

residual values, and then gridding these squared residuals.

Finally, a standard deviation grid (Figures 4-9, panel B) was

created by taking the square root of the variance grid (the

calculation did not include the number of observations,

which exceeded 70 at all grid points). It should be noted

that all base-period mean and standard deviation grid

values were localized in time and space, because each grid

value was the weighted mean of all observations within the

search ellipse surrounding that grid point. The time-space

distributions of the observations used in these base-period

calculations are shown in Figures 4-9, panel c.

Maps of single-year conditions, anomalies, and

standardized anomalies were derived for each route and

data type (Figures 10-53 and 55-66). First, each single-year

conditions map was created by gridding all observed data

from that year (panel A). Second, the base-period grid

surface, at the actual spatial-temporal location of each

observation, was subtracted from observed values,

producing a set of algebraic anomalies (i.e., residuals) for

each year, which, in turn, were used to produce annual

anomaly maps (panel B). Finally, by dividing the anomaly

at each observation point by the corresponding interpolated standard deviation (taken from the base-period

standard deviation grid surface), standardized anomalies

were calculated for every observation in a given year. Each

annual standardized anomaly map was generated by

gridding these standardized anomaly values (panel C). For

portrayal of statistically significant events, standardized

anomaly map contour intervals were chosen by picking the

15.2% and 84.8% percentile levels, as an approximation of

one standard deviation, and the 2.3% and 97.7% percentile

levels, as an approximation of two standard deviations,

from the 13-yr data set of standardized anomalies.

The grid files calculated above also were used to

produce base-period means and annual means and

anomalies for the transects as a whole. Base-period means

were calculated using all grid values from 1978 through

1990. Single-year means were obtained using the same

process, but for a single data year. Single-year anomaly

means were calculated by subtracting the base-period

mean grid values from the single-year mean grid values.

TIME PLOTS

Portrayals of the grid files indicate that neither transect

exhibits spatial coherence over its full extent. Further,

these portrayals are inconvenient for examining interannual

variations.

To deal with these two issues in the GOM, cluster

analyses (Thomas 1992) were used. Four clusters were

established to represent spatially distinct points along the

transects for the variables involved. The clusters selected

(and the reference distances to the centers of those

clusters) were Massachusetts Bay (48 km), western GOM

(165 km), eastern GOM (277 km), and Scotian Shelf (396 km).

Slices at these points were taken through all standardized

anomaly grids for the period of record to produce data for

time plots. Grid surface values were derived (again

assuming a flat surface in the neighborhood) each time the

slice crossed a grid line (each 15.22 days except where grids

were blanked due to insufficient data), and are in the same

units (standard deviations) as the grids of origin.

For the MAB, one point was selected at a reference

distance of 101 km to represent continental shelf

conditions usually not influenced by either land mass or

slope water conditions. This reference distance also marks

that point along the transect representing the mean center

of the Cold Pool (Cook 1985). A running-average fit was

generated by taking the average of all data collected within

15 mo before and after a given time-plot point.

RESULTS

In the MAB, 294 cruises were conducted during the

base period (1978-90). An additional 183 cruises were

conducted during 1991-2001, for a total of 477. In the GOM,

209 cruises were conducted during the base period. An

additional 144 cruises were conducted during 1991-2001,

for a total of 353.
Page 4

Contoured, 13-yr mean portrayals of surface temperature, bottom temperature, and surface salinity values are

shown for the MAB (Figures 4-6) and GOM (Figures 7-9).

Each figure contains three panels: (A) weighted means of

the smoothed observations for the 13-yr time frame; (B)

estimated standard deviations of the weighted mean

values; and (C) data location within the 13-yr, 452-km base

area.

Also presented are surface temperature, bottom

temperature, and surface salinity variations in time and

space for each year, 1991-2001, for the MAB and GOM

(Figures 10-53 and 55-66), with the exception of 2000 for the

GOM where sampling coverage was insufficient to produce

standard portrayals. Each single-year figure contains three

panels: (A) annual conditions; (B) departures of the annual

conditions from the 13-yr mean values expressed as

algebraic anomalies; and (C) departures of the annual

conditions from the 13-yr mean values expressed as

standardized anomalies.

Figure 67 shows the average relation between bottom

depth and reference distance along the two transects.

Figure 68 shows the spatially coherent clusters from

which GOM time plots were extracted. Figure 69 shows

time plots of surface temperature, surface salinity, and

bottom temperature at mid-shelf of the MAB. Figures 70-73

show time plots of these variables for Massachusetts Bay,

western GOM, eastern GOM, and Scotian Shelf.

In the summary of the first 13 yr of monitoring,

Benway, Jossi, Thomas et al. (1993) discussed 1978-90

baseline conditions of surface and bottom temperature and

surface salinity along the MAB and GOM transects. This

discussion is repeated below because it and the baseperiod portrayals are central to understanding the annual

and inter annual variations of these features. Also, the

variance about these mean conditions is important when

interpreting the significance of single-year departures.

Annual conditions for 1991-98 have been presented as

NAFO SCR Documents, as cited in the “Introduction.”

Although one purpose of this report was to present

recalculated departures for these years using consistent

baselines, the recalculation showed no significant

differences from those resulting from the varying base

periods utilized in these former reports. Therefore, the

1991-98 recalculated annual portrayals are presented, but

only data collected for 1998-2001 are discussed in this

report.

BASELINE CONDITIONS DURING 1978-90

Middle Atlantic Bight

Surface Temperature

Baseline conditions of surface temperature across the

MAB (Figure 4A) show annual minimum values of less

than 4°C in late February very nearshore, of 4-8°C during

mid-March on the shelf, and of 8-20°C during mid-March

progressing southeastward through the Slope and Gulf

Stream water masses. The highest rate of vernal warming

takes place along the entire transect during late June, with

peak annual temperatures greater than 22°C over the shelf

and greater than 26°C offshore achieved by late August.

From August to the end of the year temperatures decline

fairly uniformly over the entire transect.

On the shelf, the periods of highest variability in these

baseline conditions (Figure 4B) occur in early June when

standard deviations about the 1978-90 means are in excess

of 2°C. These variations are largely due to interannual

differences in the timing of the vernal warming of the

surface waters of the MAB. Variations in excess of 1°C

occur over the inner shelf during the November and

December period. The November variations can be partly

attributed to the interannual differences of timing of the fall

overturn. The December variations include recordbreaking, cold winter temperature values in 1978.

Offshore, the standard deviations about the baseline

values generally range from 2°C to more than 3°C, with the

highest values along the boundary between the Slope and

Gulf Stream water masses. The baseline values for this

region are the most variable along the transect due to the

extensive migrations of both the Shelf/Slope Front and the

Gulf Stream North Wall.

Mean surface temperature for the entire transect is

16.3°C (Table 4).

Surface Salinity

The dominant features of the time-space surface

salinity field across the shelf portion of the MAB transect

(Figure 5A) are the meltwater runoff from mid-March to late

April, and the shorter duration river discharge in midAugust, both concentrated within 30 km of Ambrose

Tower.

The Shelf-Slope Front, defined by 34.5 practical

salinity units (PSU), shows considerable spatial variation

through the year, being just seaward of the shelf break from

January through April, then migrating over 100 km further

offshore by mid-June, and returning to the area seaward of

the shelf break by October. Even greater seasonal

excursion can be seen in the 35-PSU isohaline from about

240 km in the winter to about 430 km in July and August.

Variations about these baseline conditions (Figure 5B)

are highest nearshore where standard deviations from

February through April exceed 3 PSU, and values in excess

of 1 PSU occur throughout the year, resulting from

variations in the timing and magnitude of runoff. Variations

in excess of 1 PSU occur across the shelf in June and

offshore in August and September. The influence of

upstream conditions on these values (particularly outflow

from the GOM) is not easily determined from this one

transect, but is expected to be a contributing factor.

Mean surface salinity for the entire transect is 33.81

PSU (Table 4).
Page 5

Bottom Temperature

Baseline conditions of bottom temperatures across the

MAB shelf (Figure 6A) show annual minimum values from

less than 2°C nearshore in mid-February to less than 5°C at

the shelf break in late May. The Cold Pool is a major feature

of the bottom temperature regime along this transect. It

occurs during the period between the onset of stratification

(approximately from late March inshore to late April

offshore) and the fall overturn (approximately from early

September nearshore to early December offshore) (Cook

1985). Fall overturn produces maximum bottom temperatures across the shelf, exceeding 16°C nearshore and 13°C

offshore to the shelf-slope frontal boundary.

Variations about baseline values (Figure 6B) show

standard deviations in excess of 4°C nearshore in late July

and early August associated with wind mixing of these

shallow waters, and upwelling and downwelling events

common to that area. A large portion of the inner shelf

during September and October, and the outer shelf during

October and November, have standard deviations more

than 2°C coinciding with the seaward progression of the

fall overturn. Beyond the 200-km reference distance, the

standard deviations exceed 2°C during most of the year,

reflecting the influence of the migrating Shelf-Slope Front

on the bottom, as well as the passage of warm-core rings.

Midshelf deviations more than 1°C occur during all but the

winter months, and can be largely attributed to interannual

variability in Cold Pool temperature and boundaries.

Mean bottom temperature for the entire transect is

8.8°C (Table 4).

Gulf of Maine

Surface Temperature

Baseline conditions of surface temperature across the

GOM transect (Figure 7A) range from a minimum of less

than 3°C over the Scotian Shelf in mid-March, and less than

4°C over Massachusetts Bay in late-February, to a

maximum of 19°C for Massachusetts Bay and Wilkinson

Basin, and over 14°C through Crowell Basin just onto the

Scotian Shelf in August. The highest rate of change due to

vernal warming occurs during late May through early July

across the entire transect. After August, surface

temperatures, with the exception of the mixed portions of

the Scotian Shelf, decline rapidly.

Periods of highest variability occur during June to midOctober over much of the transect (Figure 7B). Fall

overturn generally occurs during late October through

early December, leading to further variability. The high

variations over the eastern end of the transect can be

attributed to variation in the Scotian Shelf Current.

Mean surface temperature for the entire transect is

9.1°C (Table 5).

Surface Salinity

The GOM surface salinity conditions vary less than

those in the MAB, but still show a wide range of values

over the region (Figure 8A). Salinities range from a

minimum of less than 30.5 PSU during the peak runoff into

Massachusetts Bay in early June, to a maximum of near 33.5

PSU over the Scotian Shelf in early November. Unlike the

nearshore waters of the New York Bight during late summer

- early fall, there is no secondary pulse of river runoff

 The standard deviation about the baseline conditions

is less than 0.5 PSU for much of the time-space area (Figure

8B). However, deviations reaching 1 PSU occur from April

to June over portions of Massachusetts Bay. Deviations

between 0.5 and 0.7 PSU occur over portions of Crowell

Basin during January and February, and over scattered

areas at the eastern end of the transect during February

through April. In addition, standard deviations from 0.5 to

0.7 PSU occur from August through December beginning

over the Scotian Shelf and progressing westward to

include Crowell Basin.

Mean surface salinity for the entire transect is 32.43

PSU (Table 5).

Bottom Temperature

Conditions within the GOM range from a minimum of

less than 3°C over the Scotian Shelf from February through

late April, and less than 4°C over Massachusetts Bay

during the same time period (Figure 9A). Central ledges

bottom temperatures have average minima generally

between 6° and 7°C. Maximum temperatures greater than

10°C occurred over the eastern end of the transect from late

September through early November. Maximum temperatures on the western end of the transect occurred during

the same time period but only reached slightly over 9°C.

These times of maximum bottom temperature coincide with

fall overturn for these shelf areas. These maxima are absent

for the basin areas which are commonly isolated from the

overturn event by the Maine Intermediate water, and where

standard deviations are generally less than 1°C.

The largest time-space standard deviations about the

baseline conditions appear over the Scotian Shelf during

late fall and winter (Figure 9B).

Mean bottom temperature for the entire transect is

6.7°C (Table 5).

ANNUAL CONDITIONS DURING 1998-2001

Middle Atlantic Bight -- 1998

Surface Temperature

There were above-average temperatures in the

nearshore area from January through April, while there
Page 6

were below-average temperatures from the 175-km

reference distance to near the end of the transect during

mid-February through mid-May (Figure 48). The aboveaverage nearshore temperatures may have been a

consequence of the mild 1997/98 winter air temperatures as

measured at Newark and JFK airports (National Climatic

Data Center 1998).

Annual minimum surface temperatures between 5° and

6°C occurred inshore in February. From the outer shelf to

about the 350-km reference distance, the minimum of less

than 6°C occurred in March. This latter condition was from

4° to more than 8°C below baseline values, and represents

continuation of a negative trend beginning in 1996. It also

is the greatest negative departure of surface temperature in

the MAB since monitoring began, and exceeds the

previous record set in 1996 by over 2°C. These record low

offshore temperatures may be the result of increased

transport of water from the Labrador Shelf to the Slope Sea

(Rossby and Benway 2000).

Annual maximum values occurred in August along the

entire transect, reaching over 24°C on the shelf, and over

26°C near the outer end of the transect.

 In September and early October, significantly positive

anomalies occurred at about the 40-km reference distance

due, in part, to the later-than-average occurrence of the fall

overturn. A negative anomaly in excess of 4°C was

centered at the outer end of the transect in November, and

a significantly positive anomaly over 3°C occurred at the

280-km reference distance in December.

Despite the record-breaking conditions in late winter

and early spring, the transect only averaged 0.6°C below

normal in 1998 (Table 4).

Surface Salinity

Values ranged from less than 26.5 PSU in March and

again in October off Ambrose Light, to greater than 36 PSU

at the outer end of the transect in February and March

(Figure 49).

The below-baseline salinities which have dominated

this transect since 1996 continued through 1998. One

explanation for the early-in-the-year, low inshore salinities

was a combination of above-average precipitation with

mild 1997/98 winter conditions as measured at Newark and

JFK airports, both of which are compatible with heavy,

early river discharge in the apex of the MAB (National

Climatic Data Center 1998). Low offshore salinities may be

the result of increased transport of water from the Labrador

Shelf region. A low North Atlantic Oscillation (NAO) Index

for the mid-to-late 1990s has been suggested by Rossby

and Benway (2000) as a possible indicator of increased

transport from the Labrador Shelf which, in turn, may cause

a southerly shift of the Gulf Stream and lead to lower

offshore salinity values.

Most notable were: 1) the period from January into

March when significantly negative anomalies exceeded 2

PSU inshore near Ambrose Light, and the period in April

when significantly negative anomalies exceeded 3 PSU

offshore from beyond the shelf break out to about the 425-

km reference distance; and 2) negative salinity conditions

continuing through most of the remainder of the year, with

only minor exceptions offshore in August and September.

Salinities more than 1.5 PSU below baselines occurred

variously over the inner 250 km of the transect after July.

At Ambrose Light in October, salinities measured more

than 4 PSU below baselines. Another unusual pattern in

the surface salinity in 1998 was the shifting offshore of

isohalines. For example, the 30-PSU isopleth extended to

the 140-km reference distance in late July, some 100 km

seaward of average, and occupied a good deal more timespace area than average (Figure 5).

Salinity for the entire transect averaged 1.11 PSU

below average for 1998, the third consecutive year of lowerthan-average salinities, and the lowest mean annual

salinity of the 1991-99 period (Table 4).

Bottom Temperature

Minimum bottom temperatures during 1998 were less

than 6°C, occurring during February nearshore, and during

March and April over the outer shelf (Figure 50). Maximum

bottom temperatures on the inner shelf greater than 12°C

coincided with fall overturn in October. Annual bottom

temperature maxima greater than 13°C occurred over the

outer shelf in January and December.

Positive departures from baselines occurred generally

over the inner two thirds of the shelf from January to

August, with departures exceeding 3°C at Ambrose Tower

in early May, and exceeding 2°C on the mid-shelf in June.

From mid-August through November, lower-than-average

conditions prevailed, with negative anomalies exceeding

4°C on the mid-shelf in October. By December, conditions

along most of the transect were near baseline values.

The general pattern of anomalies during 1998 was

somewhat similar to those during the previous year, but for

the transect as a whole, bottom temperature values

averaged 0.2°C below the baseline, compared to 0.9°C

above the baseline in 1997 (Table 4).

Gulf of Maine -- 1998

Monthly coverage along the GOM transect has been

difficult since late 1993, and this difficulty has impacted the

value of results for all three data types in this report.

Surface salinity sampling became impossible at that time.

Therefore, the following discussion will be limited to those

time-space areas where sufficient data exist. Table 5 lists

the annual means and anomalies for the transect as a whole

since 1991 only where sufficient data exist.

Surface Temperature

Adequate coverage began in April 1998 (Figure 51).

By then temperatures measured between 0° and more than
Page 7

1°C warmer than average from western Crowell Basin well

onto the Scotian Shelf. Above-average conditions spread

westward to the central ledges in May and June, and still

further westward during July to August, when anomalies of

+2° to +3°C existed from Wilkinson Basin onto the western

Scotian Shelf, respectively. Higher-than-average air

temperatures, as measured at Boston and Providence

airports during 7 out of the first 8 mo of the year, may have

contributed to these anomalous temperatures (National

Climatic Data Center 1999).

From October to the end of the year, the Crowell Basin

and Scotian Shelf portions of the transect were colder than

average, with temperatures more than 2°C below baseline.

Offshore autumn winds led to destratification of the water

column, bringing below-average-temperature bottom water

to the surface as disclosed by SOOP water-column

temperature data. During this same time period, the

western GOM was close to baseline values.

Annual minimum temperatures occur during the period

of no coverage, so they cannot be commented on. The

annual maximum temperature exceeded 21°C, and occurred

during July in the Wilkinson Basin and central ledges

portion of the transect.

Bottom Temperature

Adequate coverage began in April (Figure 52). West

of the central ledges, the transect was slightly warmer than

average from April through December. The most

interesting feature is the significantly-below-average

bottom temperatures in Crowell Basin in April, and the

shifting of that condition eastward across the Scotian Shelf

by November, and westward back onto the central ledges

in December. These low bottom temperatures may be a

consequence of an increase in water transport from the

Labrador Shelf, as indicated by the NAO Index which

decreased during the mid-1990s (Rossby and Benway

2000).

Annual minimum bottom temperatures occur during

the period of no coverage, so they cannot be commented

on. The annual maximum bottom temperature exceeded

10°C, and was observed in Massachusetts Bay in

November.

Middle Atlantic Bight -- 1999

Surface Temperature

Annual minimum surface temperatures between 4.2°

and 6°C occurred inshore from February through March.

Annual maximum values occurred in August along the

entire transect, with temperatures reaching 24°-25°C on the

shelf, and 28°-29.4°C offshore at the outer end of the

transect (Figure 53).

From January through April, above-average temperatures prevailed in the nearshore area, much like the

conditions in 1998. In January and February, positive

anomalies existed from the outer shelf to the 320-km

reference distance. A brief period of significantly higherthan-average temperatures occurred at the very end of the

transect in January, exceeding the mean by more than 4°C.

Higher-than-normal air temperatures at Newark and JFK

airports during the 1998/99 winter months may have

contributed to the continental shelf portion of this pattern

(National Climatic Data Center 1999), while the aboveaverage temperatures at the outer end of the transect were

the consequence of the transect encountering Gulf Stream

water during January.

From late August through September, a significantly

positive anomaly with temperatures more than 2°C above

average occurred at the 50-km reference distance. This

inshore anomaly was most likely a consequence of higherthan-average air temperatures (as measured at the Newark

and JFK airports) during the spring and summer months

(National Climatic Data Center 1999). With the exception of

August and October, above-average air temperatures

prevailed through December (National Climatic Data Center

2000) and possibly contributed to water temperatures 2°C

higher than average from mid-November through December from mid-shelf to the shelf break.

Water temperatures 2°-4°C above average beyond the

shelf break during November and December coincided with

a large meander of the Gulf Stream bringing the North Wall

over 100 km shoreward of its usual position (Figure 54). In

November, this feature coincided with an anomaly from 2°

to more than 4°C below average as slope water was

displaced/entrained along the feature’s eastern edge.

For 1999, the entire transect averaged 1.0°C above the

baseline surface temperature of 16.3°C, and appears to mark

the end of a 1996-98 cool period (Table 4).

Surface Salinity

From January into June, lower-than-average salinities

were generally observed along the shelf, with values of 2.4

PSU below baseline at the 50-km reference distance in

February, and 1.5 PSU below baseline near the shelf break

in May (Figure 55). A notable exception to this pattern was

above-average salinity occurring inshore of the 25-km

reference distance in March. This anomaly may have been

a consequence of lower-than-normal winter and spring

precipitation (as measured at the Newark and JFK airports)

leading to reduced river runoff in the spring (National

Climatic Data Center 2000).

Beyond the shelf break, at the 300- to 450-km reference

distance, a low salinity anomaly was observed during

February and March, with values of 0.5-1.3 PSU below

baseline. This anomaly coincided with the passage of a

warm-core ring which entrained a long streamer of cooler,

fresher shelf water through the outer part of the transect.

Salinity values for the transect were near average for

the remainder of the year, with the notable exceptions of a

positive salinity anomaly at the shelf break coinciding with
Page 8

downwelling observed in the SOOP water-column

temperature data during July and August, and a negative

salinity anomaly at the outer end of the transect in

November. This negative anomaly coincided with the

offshore movement by the North Wall of the Gulf Stream

and the passage of a warm-core ring as mentioned above.

Salinity values for the transect as a whole ranged from

27.5 PSU in April near Ambrose Light to above 36.0 PSU at

the outer end of the transect in January, August,

September, and December. For 1999, the transect averaged

0.20 PSU below the baseline, continuing a 4-yr period of

below-average salinities (Table 4).

Bottom Temperature

From January through March 1999, bottom temperatures across the shelf were up to 4°C above average,

possibly due to unusually mild winter air temperatures (as

measured at Newark and JFK airports) experienced during

the 1998/99 winter months (National Climatic Data Center

2000) (Figure 56). For the transect as a whole, temperatures

were generally above the baseline throughout the year,

with significantly positive anomalies of water up to 8°C

above average inshore during June and July, and 3°C

above average at the 140- to 175-km reference distance

during May and June.

Annual minimum bottom temperatures of less than 5°C

were observed in March nearshore. Annual maximum

bottom temperatures greater than 19°C were observed

during June to early August nearshore, and bottom

temperatures between 18° and 19°C occurred in October on

the inner shelf, coinciding with fall overturn.

Water temperatures between 2° and 3°C below normal

were observed beyond the shelf break during May-June

and during October-December. This latter period

coincided with the passage of a large warm-core ring with

entrained streamers of cooler shelf water and a seaward

movement of the Gulf Stream North Wall mentioned above.

The transect as a whole averaged 10.6°C, the highest

mean annual temperature and departure from the baseline

during the 1991-99 period (Table 4).

Gulf of Maine -- 1999

Surface Temperature

Temperatures across the transect were near average

from January through April (Figure 57). There was no

coverage from May through the first half of July. When

sampling resumed, surface temperatures generally 1°-2°C

above average were observed in Massachusetts Bay and

the Wilkinson Basin from July through September. Surface

temperatures 2°-3°C above average were observed from

eastern Wilkinson Basin to the eastern terminus of the

transect in August. By early October, the Crowell Basin

had surface temperatures more than 4°C above the

baseline. Temperatures across the Scotian Shelf were 2°-

3°C higher than average in September. With the exception

of the Wilkinson Basin, temperatures generally remained

more than 1°C higher than average after late October.

Annual minimum surface temperature for the transect

was 1.4°C, and occurred on the Scotian Shelf in March.

Annual maximum values for the transect reached 22°C, and

occurred near the boundary of Wilkinson Basin and the

central ledges during July and August.

Bottom Temperature

The year began with average temperatures across the

Massachusetts Bay and Wilkinson Basin portions of the

transect. Colder-than-average bottom water was observed

on the central ledges and Crowell Basin in January (Figure

58). This cold water was a continuation of conditions in

late 1998 (Figure 52). The cold water remained in Crowell

Basin through March when temperatures reached more

than 2°C below average.

Starting on the western Scotian Shelf in February, and

spreading across Crowell Basin in April, water more than

1°C warmer than average occupied the time-space area.

Adequate coverage was interrupted from May through the

first half of July. However, warmer water continued to

dominate the eastern GOM when sampling resumed. By

late August, this positive anomaly had spread westward

onto the central ledges, and by late September and early

October, it had spread eastward across the Scotian Shelf

where temperatures more than 2°C above normal were

observed. These warmer-than-average bottom temperatures may be a consequence of reduced coldwater

transport from the Labrador Shelf region, as suggested by a

rising NAO Index during the late 1990s (Rossby and

Benway 2000). Temperatures for the remainder of the year

were near average for Massachusetts Bay and western

Wilkinson Basin, and more than 1°C above average from

the eastern Wilkinson Basin to the Scotian Shelf.

Annual maximum transect bottom temperatures

between 12° and 13°C occurred on the Scotian Shelf in late

September and early October. Annual minimum bottom

temperatures between 1° and 2°C were observed on the

Scotian Shelf in March.

Middle Atlantic Bight -- 2000

Surface Temperature

Annual minimum surface temperatures less than 4°C

occurred nearshore in late February (Figure 59). Minimum

temperatures offshore were between 8°C and 10°C during

the latter half of December. Annual maxima occurred in

mid-August, reaching greater than 22°C over the shelf, and

greater than 28°C near the end of the transect.

Anomalously warm water was found over the entire

transect during January and February where temperatures
Page 9

generally exceeded means by 2°-4°C on the shelf, and by

6°-8°C offshore. This anomalous feature was a

continuation of the event of late 1999 resulting from a large

Gulf Stream meander (Figure 54). For the inner 300 km of the

transect, conditions were near normal from March through

October. From the shelf break to the 300-km reference

distance in November and December, temperatures were

generally more than 2°C below average. Offshore of the

320-km reference distance, temperatures remained above

average throughout the year, exceeding means by more

than 4°C in April, May, October, and December.

For 2000, the entire transect averaged 1.1°C above

average (Table 4).

Surface Salinity

Annual minimum surface salinity values occurred from

May through August at the inshore end of the transect

(Figure 60). Annual maxima in excess of 36.5 PSU occurred

beyond the 380-km reference distance from late October to

the end of the year.

Significantly high salinities were centered at the 90-

and 180-km reference distances in February, and at the 440-

km reference distance in January. The inner 350 km of the

transect were generally near average from late March

through August. From mid-September to late October,

salinities dropped to more than 1 PSU below average over

the inner 75 km of the transect. From the shelf break to the

300-km reference distance, salinities more than 1.5 PSU

below average occurred during November and December.

The outer end of the transect was generally saltier than

average from May to the end of the year, with values

exceeding means by as much as 1-1.5 PSU.

The entire transect averaged 0.29 PSU above average

during 2000 (Table 4).

Bottom Temperature

Annual minimum bottom temperatures less than 5°C

occurred over the inner 50 km of the transect in early March

(Figure 61). Annual maxima greater than 22°C occurred at

about the 20-km reference distance in early August.

Like 1999, bottom temperatures over much of the shelf

were above average; the only exception being at the 150-km

reference distance in April and again in November. Values

exceeded means by 1°C over much of the outer shelf from

January through October, and inshore by more than 8°C in

early August.

Ordinarily, maximum bottom temperature is reached in

late September, and coincides with the fall overturn (Figure

6). In 2000, the maximum was reached in early August due

to recurring downwelling in the New York Bight apex region

(Pacific Fisheries Environmental Laboratory 2000), and a

maximum 65-km shoreward excursion of the Gulf Stream

North Wall from early June through August (Johns

Hopkins University Applied Physics Laboratory 2000).

Gulf of Maine -- 2000

As noted earlier, sampling coverage of surface and

bottom temperatures and surface salinity in the GOM

during 2000 was insufficient to produce the standard

portrayals.

Middle Atlantic Bight -- 2001

Surface Temperature

Annual minimum temperatures of less than 4°C

occurred over the inner shelf in mid-February (Figure 62).

Minimum temperatures at the 450-km reference distance

were just over 20°C, and occurred in early April. An annual

maximum greater than 22°C was reached over the entire

shelf by mid-July, with a progressive persistence from

inshore to offshore. The end of the transect reached

maximum temperatures greater than 28°C in September.

The warmer-than-average water beyond the shelf

break in 2000 generally continued to be present through

March 2001, exceeding means by more than 4°C. Brief and

spatially isolated anomalous events occurred through the

middle third of the year (e.g., cold water between the 200-

and 275-km reference distances in May, and hot water

beyond the 400-km reference distance in August and

September). This latter feature resulted from the passage of

a warm-core ring across the transect (NOAA CoastWatch

Northeast Regional Node 2002). Other significantly

positive anomalies began to appear over the outer shelf in

October, resulting from a belated fall overturn in that

region. Significantly high surface temperatures extended

over the first 340 km of the transect by December,

coinciding with the second-warmest November-January air

temperatures in several bordering states since weather

records began in 1895 (National Oceanic and Atmospheric

Administration 2002).

For 2001, the entire transect averaged 0.8°C above

average (Table 4).

Surface Salinity

Annual minimum salinities of less than 27.5 PSU were

centered very nearshore in early April (Figure 63). Highest

values occurred from January through mid-March at the

outer end of the transect.

Salinities more than 1.5 PSU below average briefly

occurred between the 230- and 310-km references distances

in January, a remnant of a feature with an inshoreundulating time-space margin during 2000. Salinities more

than 2.0 PSU below average also occurred seaward of the

spring runoff plume during April and May. An area

centered on the shelf break in between April and June

reached significantly low values (by more than 2.0 PSU)
Page 10

during the middle of this time period. Moderately-higherthan-average salinities occurred offshore during the first 3

mo of the year, and again at isolated locations inshore and

offshore in August and September, and offshore in

December. These offshore anomalies correspond well with

positive anomalies of surface temperature.

For 2001, the entire transect averaged 0.09 PSU above

average (Table 4).

Bottom Temperature

Typical annual minimum bottom temperatures of less

than 4°C occurred in February at about the 50-km reference

distance (Figure 64). Annual maximum temperatures in

excess of 18°C occurred nearshore in July.

In terms of departures from the 1978-90 baselines, the

first half of the year generally remained within normal

variability. By early July, significantly-warmer-thanaverage water was present over more than 50 km of the

outer shelf, and anomalously cooler water occupied the

slope area beyond 200 km. The 10-11°C water of the upper

100 m of a warm-core ring was found about 65 km

shoreward of the average location of water with these

temperatures, leading to the positive anomalies. Likewise,

the ordinarily deeper and colder water of the ring was

present at shallower depths in August and September due

to the ring’s shoreward position.

Gulf of Maine -- 2001

Surface Temperature

Continued poor coverage occurred for the transect in

2001 (Figure 65). Near-normal annual minimum temperatures less than 4°C occurred in Massachusetts Bay during

February and early March. Annual minimum values of 2°C

were recorded on the eastern end of the transect from

February to late March.

Temperatures over the western margins of the Scotian

Shelf were more than 1°C below average during the same

February-to-late-March period. Measurements taken in

June over the western 300 km of the transect indicate that

that portion of the GOM was headed for an anomalously

warm summer, perhaps exceeding means by nearly 3°C;

lack of coverage prevents verification. However, from June

through September, the western Scotian Shelf had

significantly low temperatures, falling below the baselines

by more than 3°C. From late November to the end of the

year, temperatures were near average over the entire

transect.

No annual means for the entire transect were

calculated.

Bottom Temperature

Annual minimum bottom temperatures on the ends of

the transects were similar to those for surface temperatures

in magnitude (i.e., less than 4°C in the west; less than 2°C in

the east), although the minima persisted longer at the

bottom than they did at the surface (Figure 66). No

sampling occurred during the usual annual maxima on the

bottom.

Significantly warm water appeared from the 150- to

230-km reference distances in January. By June, this

feature had reached westward to about the 90-km reference

distance. This westward movement of warm water is

consistent with intrusions of slope water from the

Northeast Channel that follows the deeper channels of the

GOM in areas of the sampling transect. Figure 66, Panel B,

shows continuity of the features during the first 6 mo of the

year, while panel C does not. This difference is due to the

temperature departures in April not reaching significant

levels.

The significantly cold water between the 240- and 320-

km reference distances during mid-March to mid-April is a

westward extension of the anomalously cold water which

occurred over the Scotian Shelf during at least the first 9 mo

of the year. Here, and in the vicinity of Cape Sable in June,

bottom temperatures were more than 2°C below average.

Coverage was not sufficient to allow calculation of a

transect-wide average of bottom temperature for the year.

TIME PLOTS OF ANOMALIES FOR THE 1978-2001

TIME SERIES

The five time plots are the result of taking a multiyear

slice through the standardized anomaly grids at one

reference distance in the MAB, and four in the GOM. An

adequate analysis of these time plots is beyond the scope

of this paper. However, the overlay of a 15-mo running

average reveals features of the signal that are felt to be

significant enough to warrant comment.

Middle Atlantic Bight

The location chosen to represent the MAB was the

101-km reference distance, or approximately 40°N, 73°W,

along the transect (Figure 1a).

Surface Temperature

Isolated months during 1978-2001 departed significantly from the 1978-90 means (Figure 69). Departures in

excess of two standard deviations were more numerous in
Page 11

the 1990s than in the previous years, even after

adjustments to account for the 1990s not being included in

the base period. Sequential, monthly positive or negative

departures were more numerous in the 1990s than in

previous years. The December 2001 and January 2002

anomalies both exceeded the previous series record of

September 1990.

Finally, anomalies averaged higher after 1990 (+0.39)

than through 1990 (-0.07).

Surface Salinity

Isolated months during 1978-2001 departed significantly from the 1978-90 means, and are especially more

prevalent in the late 1990s than in earlier years (Figure 69).

There is more month-to-month consistency in the surface

salinity departures than in the surface temperature

departures. Uninterrupted positive departures of 2 yr (i.e.,

1980-81 and 1985-86), and uninterrupted negative departures of 2-3 yr (i.e., 1996-98 and 1998-99), occurred.

No trend during the time period was apparent,

although anomalies averaged lower after 1990 (-0.34) than

through 1990 (+0.17).

Bottom Temperature

Greater departures in the 1990s also occurred in the

bottom temperature data (Figure 69). The phase changes of

the smoothed values are quite similar through the time

period for the bottom temperature and the surface

temperature. Departures from 1994 through 2000 were

considerably larger than during the earlier part of the series.

Anomalies averaged slightly higher after 1990 (+0.10)

than through 1990 (-0.07).

Massachusetts Bay

The location chosen to represent Massachusetts Bay

was the 48-km reference distance, or approximately

70°20’W, along the transect (Figure 1b).

Surface Temperature

With the exception of isolated monthly departures

near, or in excess of, two standard deviations, the 1978-88

period exhibited no enduring anomalous surface temperatures (Figure 70). During 1989 to early 1990 and during 1992

to mid-1994, mostly colder-than-average conditions

prevailed. Positive anomalies were briefly present from

mid-1990 through 1991. After 2000, most departures were

positive.

The smoothed values depart from the mean considerably less than those for surface temperature in the MAB.

No trend during the time period was apparent.

Surface Salinity

Salinity anomalies generally shifted from negative

values at the beginning of 1978 to a positive peak by mid1980, declined generally through early 1984 to a period

minimum, rose sharply to a positive peak in mid-1985,

declined generally to a negative point in late 1987, and after

generally climbing to a positive peak in 1990, again declined

generally to a negative point at the end of the sampling

period in 1993 (Figure 70). The longest sustained period

was that of negative anomalies in 1983 and 1984.

Bottom Temperature

From 1978 to 1981, bottom temperatures were near

normal (Figure 70). Positive departures occurred during

1982 and 1983, followed by near-average values in the mid1980s. From 1987 through early 1990, and from early 1992 to

mid-1994, values were generally negative, after which

departures became inconsistent, with several significantly

warm months. Departures in the late 1990s were less

excessive than in the earlier period, and might result in a

warming trend for these data -- anomalies averaged slightly

higher after 1990 (+0.10) than through 1990 (-0.11).

Western Gulf of Maine

The location chosen to represent the western GOM

was the 165-km reference distance, or approximately

68°55’W, along the transect (Figure 1b).

Surface Temperature

Variations from 1978 through 1990 followed a similar

pattern to those for surface temperature anomalies in

Massachusetts Bay, except that they were of slightly larger

magnitude (Figure 71). Positive anomalies generally

occurred from 1983 to early 1985; negative anomalies

occurred in 1982, generally for a fairly prolonged period

from mid-1986 to 1991, and generally again from mid-1991 to

1994. This pattern was followed in 1996 by the lowest

annual average temperature anomaly of the period, from

which values began increasing to reach their highest of the

period by 2000. This latter pattern was not seen in

Massachusetts Bay.

No trend was apparent, although the last 5 yr of the

period exhibited consistent and numerous significant

positive departures.

Surface Salinity

The western GOM surface salinity pattern follows that

of Massachusetts Bay very closely (Figure 71). The only
Page 12

major exception was that in the western GOM, the 1985

positive anomalies persisted to the beginning of 1987. The

maximum positive anomaly of the time series occurred in

mid-1985, and the maximum negative anomaly occurred in

mid-1984.

No trend was apparent during the time period.

Bottom Temperature

Patterns here were also very similar to those for bottom

temperature in Massachusetts Bay, although the departures were of less magnitude (Figure71). The maximum

negative anomaly of the time series occurred in late 1996.

Positive anomalies generally dominated from 1991 to near

the end of 2001, with the maximum positive anomaly of the

time series occurring in mid-1991. Variations were larger in

the late 1990s than earlier in the period.

Anomalies averaged higher after 1990 (+0.43) than

they did through 1990 (-0.29).

Eastern Gulf of Maine

The location chosen to represent the eastern GOM

was the 277-km reference distance, or approximately

67°37’W, along the transect (Figure 1b).

Surface Temperature

Patterns in the eastern GOM followed those to the

west very closely (Figure 72). The maximum negative

anomaly of the time series occurred in early 1988, and the

maximum positive anomaly of the time series occurred in

late 1999. The only major difference from the pattern to the

west occurred in 1998 when a brief but major shift to cold

water interrupted a general 4-yr uptrend. The larger

anomalies of the late 1990s -- compared to the earlier years

-- are again present.

Anomalies averaged higher after 1990 (+0.22) than

they did through 1990 (-0.07), largely as a result of values

from 1998 through 2000.

Surface Salinity

Variations in this portion of the GOM are quite similar

in pattern and magnitude to those to the west (Figure 72).

The maximum positive anomaly of the time series occurred

in early 1990, and the maximum negative anomalies of the

time series occurred in 1984 and 1987.

Negative anomalies dominated after 1986.

Bottom Temperature

Patterns and magnitudes of bottom temperature

departures in the eastern GOM are quite similar to those in

the western GOM from 1978 to 1990 (Figure 72). Thereafter,

the patterns begin to go out of phase, and the magnitudes,

especially in the late 1990s, were much more negative in the

eastern GOM, exhibiting significantly-lower-than-average

temperatures in 1998 and early 1999. The maximum positive

and negative anomalies of the time series occurred in 1998

and 1997, respectively, and were part of the usual late 1990s

relatively extreme anomalies.

Anomalies averaged higher after 1990 (+0.08) than

through 1990 (+0.32).

Scotian Shelf

The location chosen to represent the Scotian Shelf was

the 396-km reference distance, or approximately 66°15’W,

along the transect (Figure 1b).

Surface Temperature

From 1978 through mid-1993, surface temperature

anomaly patterns on the Scotian Shelf generally followed

those in the eastern GOM (Figure 73). However, the

magnitudes of departure in the former were considerably

less than those in the latter. From 1993 to 1998,

temperatures varied in opposite phase to those to the west.

By 1999, both areas exhibited warmer-than-average

temperatures, with the departures on the Scotian Shelf of

lesser magnitude. Values returned to near average at the

end of 2000, became negative during much of 2001, and

returned to a positive phase at the end of the time series.

Larger anomalies were apparent during the 1990s than

during earlier years, and no trend was seen over the entire

time period.

Surface Salinity

Patterns of variation in surface salinity deviations

were generally in phase with those in the eastern and

western GOM, and to a lesser extent with those in

Massachusetts Bay, during the entire period of sampling.

However, like surface temperature, the salinity departures

from means were less than those in the western sections.

No trend was apparent during the time period.

Bottom Temperature

Patterns of variation in bottom temperature deviations

as determined by the smoothed data seemed to be in

synchrony -- except for 1988-92 -- with the patterns in the

eastern GOM (Figure 73). However, these shifts often

resulted in Scotian Shelf temperatures being in a positive

phase while those to the west were in a negative phase, and

vice versa.

Bottom temperature measurements from the eastern

GOM are obtained from considerably greater depths

(Figure 72) than the measurements from the Scotian Shelf,
Page 13

and would be expected to represent different water masses.

Unfortunately, an investigation of a connection between

these patterns is beyond the scope of this paper.

DISCUSSION

This paper presents time-space portrayals of surface

temperature and salinity and bottom temperature data from

the MAB and the GOM during 1991-2001. The style of the

portrayals was chosen to aid in comparison of these data

with those published earlier (Benway, Jossi, Thomas et al.

1993). Also presented are time plots of anomalous

conditions of these data for the 1978-2001 period.

Record high and low values for all three data types,

and for both geographical regions, all occurred during the

1990s. Surface temperatures along both transects during

1996 averaged the lowest during the entire 1978-2001

period, departing from baselines by 1.1°C in both regions.

The highest annual average surface temperatures in the

MAB occurred during 1994 and 1995, and in the GOM

during 1991. Three years of consistently low surface

temperatures in the MAB ended in 1999.

Surface salinities in the MAB had their lowest annual

averages in 1998, departing from baselines by 1.1 PSU.

Four years of consistently low surface salinities in the

MAB ended in 2000.

Bottom temperatures in the MAB were lowest in 1994,

averaging 1.4°C below the base period. Lowest bottom

temperatures in the GOM occurred in 1997, averaging 0.5°C

below the baseline. In the MAB, 1999 had the highest

average bottom temperatures for the period of record

(+1.8). In the GOM, 1994 had the highest average bottom

temperatures for the period of record (+0.5).

As the monitoring program continues, special

attention will be paid to the relatively extreme behavior of

the ecosystem that occurred in the 1990s.

ACKNOWLEDGMENTS

For their generous cooperation for over a decade, we

extend our appreciation to the captains, officers, and crews

of the: Oleander, Bermuda Container Lines; Yankee

Clipper, Claus Spect, Hamburg, Germany; and C/V

Skogafoss and C/V Godafoss, Skogaline Ltd., St. John,

Antigua. Appreciation also is proffered to all individuals

who have volunteered to ride these ships, in particular

those riding the Oleander. Special thanks are extended to

the staff of the National Ocean Service’s Office of Ocean

Observations for their continued support. Lastly, for all

employees who have passed through this office and for all

other participating vessels over the last 22 yr too numerous

to name, thanks for a job well done.

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surface salinities: New York to the Gulf Stream,

Massachusetts to Cape Sable N.S., 1997. NAFO

[Northwest Atl. Fish. Organ.] SCR [Sci. Counc. Res.]

Doc. 98/17; 12 p.

Benway, R.L.; Jossi, J.W. 1994. Surface and bottom

temperatures, and surface salinities: New York to the

Gulf Stream, Massachusetts to Cape Sable, N.S., 1993.

NAFO [Northwest Atl. Fish. Organ.] SCR [Sci. Counc.

Res.] Doc. 94/15; 16 p.

Benway, R.L.; Jossi, J.W. 1995. Surface and bottom

temperatures, and surface salinities: New York to the

Gulf Stream, Massachusetts to Cape Sable, N.S., 1994.

NAFO [Northwest Atl. Fish. Organ.] SCR [Sci. Counc.

Res.] Doc. 95/15; 16 p.

Benway, R.L.; Jossi, J.W. 1996. Surface and bottom

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temperatures, and surface salinities: New York to the

Gulf Stream, Massachusetts to Cape Sable, N.S., 1996.

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Res.] Doc. 97/06; 11 p.

Benway, R.L.; Jossi, J.W. 1998. Departures of 1996

temperatures and salinities in the Middle Atlantic

Bight and Gulf of Maine from historical means. J.

Northwest Atl. Fish. Sci. 24:61-86.

Benway, R.L.; Jossi, J.W. In review. Ships of opportunity

(SOOP) survey sampling. In: Griswold, C.A., ed.

MARMAP ecosystem surveys: operations manual.

Available from: National Marine Fisheries Service, 28

Tarzwell Dr., Narragansett, RI 02882.

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and bottom temperatures, and surface salinities: New

York to the Gulf Stream, Massachusetts to Cape Sable,

N.S., 1992. NAFO [Northwest Atl. Fish. Organ.] SCR

[Sci. Counc. Res.] Doc. 93/27; 15 p.

Benway, R.L.; Jossi, J.W.; Prezioso, J. 1992. Surface and

bottom temperatures, and surface salinities: New York

to the Gulf Stream, Massachusetts to Cape Sable, N.S.,

1991. NAFO [Northwest Atl. Fish. Organ.] SCR [Sci.

Counc. Res.] Doc. 92/16; 19 p.

Benway, R.L.; Jossi, J.W.; Thomas, K.P.; Goulet, J.R. 1993.

Variability of temperature and salinity in the Middle

Atlantic Bight and Gulf of Maine. NOAA [Natl. Ocean.

Atmos. Adm.] Tech. Rep. NMFS [Natl. Mar. Fish.

Serv.] 112; 108 p.

Cook, S.K. 1985. Temperature conditions in the Cold Pool

1977-1981: a comparison between Southern New

England and New York transects. NOAA [Natl. Ocean.
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Atmos. Adm.] Tech. Rep. NMFS [Natl. Mar. Fish.

Serv.] 24; 22 p.

Georgi, D.T.; Dean, J.P.; Chase, J.A. 1980. Temperature

calibration of expendable bathythermographs. Ocean

Eng. 7:491-499.

Ingham, M.C., editor; Armstrong, R.S.; Chamberlin, J.L.;

Cook, S.K.; Mountain, D.G.; Schlitz, R.G.; Thomas,

J.P.; Bisagni, J.J.; Paul, J.F.; Warsh, C.E. 1982.

Summary of the physical oceanographic processes

and features pertinent to pollution distribution in the

coastal and offshore waters of the northeastern United

States, Virginia to Maine. NOAA [Natl. Ocean. Atmos.

Adm.] Tech. Memo. NMFS [Natl. Mar. Fish. Serv.]-F/

NEC-17; 166 p.

Johns Hopkins University Applied Physics Laboratory.

2000. Gulf Stream, multi-day merged data. <http://

fermi.jhuapl.edu:80/avhrr/gs/averages/index.htm>.

Accessed Aug. 30, 2001.

Jossi, J.W.; Goulet, J.R.; Green, J.R. 1992. 30 years of

zooplankton variability in the Gulf of Maine. In:

Wiggins, J.; Moores, C.N.K., eds. Proceedings of the

Gulf of Maine Scientific Workshop, Woods Hole, MA,

8-10 January, 1991. Boston, MA: Univ. of

Massachusetts Urban Harbors Inst.: 255-258.

National Climatic Data Center. 1998. Local climatological

data, edited. <http://www.ncdc.noaa.gov/pdfs/lcd/

lcd.html>. Accessed Oct. 2, 2000.

National Climatic Data Center. 1999. Local climatological

data, edited. <http://www.ncdc.noaa.gov/pdfs/lcd/

lcd.html>. Accessed Oct. 16, 2000.

National Climatic Data Center. 2000. Local climatological

data, edited. <http://www.ncdc.noaa.gov/pdfs/lcd/

lcd.html>. Accessed Oct. 16, 2000.

National Oceanic and Atmospheric Administration. 2002.

November 2001 - January 2002 warmest on record in

U.S.; global temperatures warmest on record in

January. <http://www.noaanews.noaa.gov/stories/

s869.htm>.

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sea surface temperature. <http://newton.gso.uri.edu/

thermo6/ocean_goes_result/html_dir/

thumb_page1.html>. Accessed Mar. 15, 2002.

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www.pfeg.noaa.gov>. Accessed Aug. 30, 2001.

Rossby, T.,; Benway, R.L. 2000. Slow variations in mean

path of the Gulf Stream east of Cape Hatteras.

Geophys. Res. Lett. 27(1):117-120.

Sippican Corporation. 1970. XBT system linearity

equation: ocean engineering bulletin No. 1. Available

from: Sippican Corp., Marion, MA.

Steinhart, J.S.; Hart, S.R. 1968. Calibration curves for

thermistors. Deep-Sea Res. 15:497-503.

Thomas, K.P. 1992. Initiation and decline of Ceratium

tripos blooms in the Gulf of Maine: dependence upon

water column structure. [M.S. thesis.] Kingston, RI:

Univ. of Rhode Island; 127 p.

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scale 1978. UNESCO Tech. Pap. Mar. Sci. 37; 144 p.
Page 15

Table 1. Equations for calculating depth during an expendable bathythermograph deployment

(Sippican Corporation 1970)

Probe Type Depth Range (m) Equationa

T-4 0-460 D = [(6.472) × (T - 0.00216) × (T2)]

T-6 0-460 D = [(6.472) × (T - 0.00216) × (T2

)]

T-7 0-760 D = [(6.472) × (T - 0.00216) × (T2

)]

T-10 0-200 D = [(6.301) × (T - 0.00216) × (T2

)]

a

 D = depth of voltage reading in meters; T = time of descent in seconds.

Table 2. Gridding methods and elliptical search radii for both sampling routes and grid types

Route

Grid

Type Grid Size Grid Limits

No. of

Grids Gridding Method

Search

Radii Anisotropy

MB

and

MC

Single

year

x = 17.38 km;

y = 15.22 days

x = 0-452 km;

y = 0-365.25

days

x = 27;

y = 25

Kriging:

*linear variogram

*no nugget effect

*nearest 50 neighbors

*data outside grid used

*no smoothing

*blank grid if less than

four values in search

x = 60 km;

y = 70 days

1:1 circular

search of scaled

data

MB

and

MC

Base

period

x = 17.38 km;

y = 15.22 days

x = 0-452 km;

y = 0-365.25

days

x = 27;

y = 25

Inverse distance

weighting:

*weighting factor = 2

*nearest 200 neighbors

*data outside grid used

*duplicates averaged

*no smoothing

x = 30 km;

y = 35 days

1:1 circular

search of scaled

data
Page 16

Table 3. Summary statistics for gridding residuals for the Middle Atlantic Bight (Route MB) and Gulf of Maine (Route MC).

(Route MB single-year residuals resulted from gridding of all surface and bottom temperature and surface salinity data

from 1978 through 2001. Route MC single-year surface salinity residuals resulted from gridding only data from 1978

though 1993. Base-period residuals resulted from gridding of all data from 1978 through 1990. Normality was based

on the Kolomogorov D statistic.)

Data Type

Grid

Type N Min. Max. Mean s Skewness Kurtosis Normality

Route MB

Surface

temperature

Single

year

7607 -5.110 +6.486 -0.008 0.733 +0.234 7.627 D = 0.083;

P > D < 0.010

Base

period

5056 -8.676 +10.479 -0.040 1.851 -0.009 1.310 D = 0.035;

P > D < 0.010

Surface

salinity

Single

year

7538 -5.003 +3.233 +0.003 0.370 -0.819 15.045 D = 0.111;

P > D < 0.010

Base

period

5091 -10.090 +5.977 +0.024 0.906 -0.355 7.683 D = 0.054;

P > D < 0.010

Bottom

temperature

Single

year

3545 -5.132 +10.700 +0.036 0.798 +1.278 16.521 D = 0.107;

P > D < 0.010

Base

period

2380 -6.165 +10.188 -0.0350 2.067 +12.164 368.937 D = 0.103;

P > D < 0.010

Route MC

Surface

temperature

Single

year

4668 -2.914 +2.870 -0.004 0.408 +0.349 5.176 D = 0.081;

P > D < 0.010

Base

period

3317 -4.164 +6.186 +0.024 1.135 +0.333 1.937 D = 0.041;

P > D < 0.010

Surface

salinity

Single

year

4129 -1.973 +1.171 -0.000 0.157 -1.299 23.3431 D = 0.139;

P > D < 0.010

Base

period

3340 -4.256 +1.963 -0.018 0.473 -0.961 5.338 D = 0.062;

P > D < 0.010

Bottom

temperature

Single

year

2654 -2.359 +1.891 -0.003 0.283 -0.125 6.125 D = 0.073;

P > D < 0.010

Base

period

1797 -3.789 +4.833 -0.030 0.798 +0.039 1.870 D = 0.035;

P > D < 0.010
Page 17

Table 4. Annual mean values and anomalies of surface temperatures and salinities and bottom temperatures

for the entire Middle Atlantic Bight transect from 1991 through 2001

Year(s) Measure

Surface

Temperature (°C)

Surface

Salinity (PSU)

Bottom

Temperature (°C)

1978-90 Baseline value 16.3 33.81 8.8

1991

Mean value 17.5 33.82 8.8

Mean anomaly +1.2 +0.01 0.0

1992

Mean value 16.0 34.53 9.0

Mean anomaly -0.3 +0.72 0.2

1993

Mean value 15.7 33.57 8.9

Mean anomaly -0.6 -0.24 0.1

1994

Mean value 17.6 34.06 7.4

Mean anomaly +1.3 +0.25 -1.4

1995

Mean value 17.6 34.32 9.9

Mean anomaly +1.3 +0.51 1.1

1996

Mean value 15.2 32.86 8.5

Mean anomaly -1.1 -0.95 -0.3

1997

Mean value 15.5 33.27 9.7

Mean anomaly -0.8 -0.54 0.9

1998

Mean value 15.7 32.70 8.6

Mean anomaly -0.6 -1.11 -0.2

1999

Mean value 17.3 33.61 10.6

Mean anomaly +1.0 -0.20 1.8

2000

Mean value 17.4 34.10 10.4

Mean anomaly +1.1 +0.29 1.6

2001

Mean value 17.1 33.90 9.8

Mean anomaly +0.8 +0.09 1.0
Page 18

Table 5. Annual mean values and anomalies of surface temperatures and salinities and bottom temperatures

for the entire Gulf of Maine transect from 1991 through 1997. (Insufficient coverage from 1998

through 2001 prevented calculation of annual means.)

Year(s) Measure

Surface

Temperature (°C)

Surface

Salinity (PSU)

Bottom

Temperature (°C)

1978-90 Baseline value 9.1 32.43 6.7

1991

Mean value 9.5 32.24 7.0

Mean anomaly +0.4 -0.19 +0.3

1992

Mean value 8.4 32.00 6.6

Mean anomaly -0.7 -0.43 -0.1

1993

Mean value 8.9 31.93 6.5

Mean anomaly -0.2 -0.50 -0.2

1994

Mean value 9.1 7.2

Mean anomaly 0.0 +0.5

1995

Mean value 9.4 7.1

Mean anomaly +0.3 +0.4

1996

Mean value 8.0 6.9

Mean anomaly -1.1 +0.2

1997

Mean value 9.0 6.2

Mean anomaly -0.1 -0.5
Page 19 
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Page 25 

Figure 6. Mean bottom temperature conditions along the Middle Atlantic Bight route during 1978-90. A. Means of measured 

values (°C). B. Standard deviations of measured values (°C). C. Station locations in time and space. (In panels A and 

B, values decline on those sides of contour lines with hachures.) 
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Figure 56. Bottom temperature conditions along the Middle Atlantic Bight transect during 1999. A. Measured values (°C) in time

and space. B. Anomalies in time and space based on 1978-90 means. C. Standardized anomalies (i.e., standard 

deviations) in time and space based on 1978-90 means and variances (scale given in legend). (In panels A and B, 

values decline on those sides of contour lines with hachures.) 
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°

i.e.
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Page 92 
Publishing in NOAA Technical Memorandum NMFS-NE

Manuscript Qualification

This series represents a secondary level of scientific publishing

in the National Marine Fisheries Service (NMFS). For all issues, the

series employs thorough internal scientific review, but not necessarily external scientific review. For most issues, the series employs

rigorous technical and copy editing. Manuscripts that may warrant

a primary level of scientific publishing should be initially submitted

to one of NMFS’s primary series (i.e., Fishery Bulletin, NOAA

Technical Report NMFS, or Marine Fisheries Review).

Identical, or fundamentally identical, manuscripts should not

be concurrently submitted to this and any other publication series.

Manuscripts which have been rejected by any primary series strictly

because of geographic or temporal limitations may be submitted to

this series.

Manuscripts by Northeast Fisheries Science Center (NEFSC)

authors will be published in this series upon approval by the NEFSC's

Deputy Science & Research Director. Manuscripts by non-NEFSC

authors may be published in this series if: 1) the manuscript serves

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As much as possible, use traditional scientific manuscript organization for sections: “Introduction,” “Study Area,” “Methods &

Materials,” “Results,” “Discussion” and/or “Conclusions,” “Acknowledgments,” and “References Cited.”

Style: All NEFSC publication and report series are obligated

to conform to the style contained in the most recent edition of the

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manual is silent on many aspects of scientific manuscripts. NEFSC

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fifth edition.

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all necessary bibliographic information. For abbreviating serial titles

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address of source.

For spelling of scientific and common names of fishes,

mollusks, and decapod crustaceans from the United States and

Canada, use Special Publications No. 20 (fishes), 26 (mollusks), and

17 (decapod crustaceans) of the American Fisheries Society (Bethesda,

MD). For spelling of scientific and common names of marine

mammals, use Special Publication No. 4 of the Society for Marine

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the English Language Unabridged (Springfield, MA: G.&C.

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Send all materials and address all correspondence to:

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166 Water Street

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NORTHEAST FISHERIES SCIENCE CENTER

Dr. John G. Boreman, Acting Science & Research Director

Capt. John T. Moakley, Operations, Management & Information Services Chief

Teri L. Frady, Research Communications Chief

Jon A. Gibson, Biological Sciences Editor & Laura S. Garner, Editor
Research Communications Unit

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National Marine Fisheries Service, NOAA

166 Water St.

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The mission of NOAA's National Marine Fisheries Service (NMFS) is "stewardship of living marine resources for the benefit of the

nation through their science-based conservation and management and promotion of the health of their environment." As the research

arm of the NMFS's Northeast Region, the Northeast Fisheries Science Center (NEFSC) supports the NMFS mission by "planning,

developing, and managing multidisciplinary programs of basic and applied research to: 1) better understand the living marine resources

(including marine mammals) of the Northwest Atlantic, and the environmental quality essential for their existence and continued

productivity; and 2) describe and provide to management, industry, and the public, options for the utilization and conservation of living

marine resources and maintenance of environmental quality which are consistent with national and regional goals and needs, and with

international commitments." Results of NEFSC research are largely reported in primary scientific media (e.g., anonymously-peerreviewed scientific journals). However, to assist itself in providing data, information, and advice to its constituents, the NEFSC

occasionally releases its results in its own media. Those media are in four categories:

Northeast Fisheries Science Center Reference Document -- This series is issued irregularly. The series typically includes: data

reports on field and lab observations or experiments; progress reports on continuing experiments, monitoring, and assessments;

manuals describing routine surveying and sampling programs; background papers for, and summary reports of, scientific meetings;

and simple bibliographies. Issues receive internal scientific review, but no technical or copy editing.

Resource Survey Report (formerly Fishermen's Report) -- This information report is a quick-turnaround report on the distribution

and relative abundance of selected living marine resources as derived from each of the NEFSC's periodic research vessel surveys

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OBTAINING A COPY: To obtain a copy of a NOAA Technical Memorandum NMFS-NE or a Northeast Fisheries Science

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Editorial Office (166 Water St., Woods Hole, MA 02543-1026; 508-495-2228) or consult the NEFSC webpage on "Reports

and Publications" (http://www.nefsc.noaa.gov/nefsc/publications/).

ANY USE OF TRADE OR BRAND NAMES IN ANY NEFSC PUBLICATION OR REPORT DOES NOT IMPLY

ENDORSEMENT.

NOAA Technical Memorandum NMFS-NE -- This series is issued irregularly. The series typically includes: data reports of longterm or large-area studies; synthesis reports for major resources or habitats; analytical reports of environmental conditions or

phenomena; annual reports of assessment or monitoring programs; manuals describing unprecedented field and lab techniques;

literature surveys of major resource or habitat topics; proceedings and collected papers of scientific meetings; and indexed and/

or annotated bibliographies. All issues receive internal scientific review and most issues receive technical and copy editing.

The Shark Tagger -- This newsletter is an annual summary of tagging and recapture data on large pelagic sharks as derived from

the NMFS's Cooperative Shark Tagging Program; it also presents information on the biology (movement, growth, reproduction,

etc.) of these sharks as subsequently derived from the tagging and recapture data. There is internal scientific review, but no technical

or copy editing, of this newsletter.