NOAA Technical Report NESDIS 79

QUALITY CONTROL AND PROCESSING OF HISTORICAL

OCEANOGRAPHIC NUTRIENT DATA

Margarita E. Conkright

Timothy P. Boyer

Sydney Levitus

National Oceanographic Data Center

Ocean Climate Laboratory

Washington, D.C. April 1994

U.S. DEPARTMENT OF COMMERCE Ronald H. Brown, Secretary

National Oceanic and Atmospheric Administration D. James Baker, Under Secretary

National Environmental Satellite, Data, and Information Service Robert S. Winokur, Assistant

Administrator
National Oceanographic Data Center

USER SERVICES

This publication, as well as detailed information about NODC data holdings, products, and

services, is available from the:

National Oceanographic Data Center

User Services Branch

NOAA/NESDIS E/OC21

1825 Connecticut Avenue, NW

Washington, DC 20235

 Telephone: (202) 606-4549

 Fax: (202) 606-4586

 Omnet:NODC.WDCA

 Internet: services@nodc.noaa.gov
CONTENTS

List of tables..........................................................................................................................iv

List of figures ......................................................................................................................vii

Acknowledgements...............................................................................................................ix

Abstract..................................................................................................................................1

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

Data sources and distributions ...............................................................................................2

Quality control .......................................................................................................................3

A. Preliminary quality control .......................................................................................4

B. Range check on the observed level data ....................................................................4

(a) Phosphate .......................................................................................................5

(b) Nitrate ............................................................................................................6

(c) Silicate............................................................................................................6

C. Interpolation from observed to standard depth levels.................................................7

D. Statistical analysis of data at standard depth levels....................................................8

E. Objective analysis.....................................................................................................8

Summary and future work ......................................................................................................9

References............................................................................................................................11

Appendix 1. Data flags and data availability.........................................................................14

A. Depth error flags..............................................................................................................14

B. Profile error flags.............................................................................................................14

Appendix 2. Fortran program to read and write observed level and standard level

vertical profile data ..............................................................................................................16

Appendix 3. Sample output of observed level nutrient data...................................................21

Appendix 4. One-degree square horizontal co-ordinate system of the analyzed fields ..........22

Appendix 5. Five-degree square horizontal co-ordinate system of the analyzed fields...........23

Appendix 6. WMO square chart ...........................................................................................24

iii
LIST OF TABLES

Table 1. Distribution with depth of phosphate, nitrate and silicate observations.

Table 2. Number of phosphate, nitrate and silicate profiles for each season in the SD and SD2 files.

Table 3. Frequency distribution (in percent) of phosphate values in the North Pacific Ocean

Table 4. Phosphate ranges for the Atlantic Ocean as a function of depth.

Table 5. Phosphate ranges for the Pacific Ocean as a function of depth.

Table 6. Phosphate ranges for the Indian Ocean as a function of depth.

Table 7. Phosphate ranges for the Southern and Arctic Oceans as a function of depth.

Table 8. Number of phosphate range outliers as a function of depth in the Atlantic Ocean. (N=

number of observations, High= outliers exceeding high range values, Low= outliers below

the low range values).

Table 9. Number of phosphate range outliers as a function of depth in the Pacific Ocean. (N=

number of observations, High= outliers exceeding high range values, Low= outliers below

the low range values).

Table 10. Number of phosphate range outliers as a function of depth in the Indian Ocean. (N=

number of observations, High= outliers exceeding high range values, Low= outliers

below the low range values).

Table 11. Number of phosphate range outliers as a function of depth in the Southern and

Arctic Oceans. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values).

Table 12. Nitrate ranges for the Atlantic Ocean as a function of depth.

Table 13. Nitrate ranges for the Pacific Ocean as a function of depth.

Table 14. Nitrate ranges for the Indian Ocean as a function of depth.

Table 15. Nitrate ranges for the Southern and Arctic Oceans as a function of depth.

Table 16. Number of nitrate range outliers as a function of depth in the Atlantic Ocean. (N=

number of observations, High= outliers exceeding high range values, Low= outliers

below the low range values).

iv
Table 17. Number of nitrate range outliers as a function of depth in the Pacific Ocean. (N= number

of observations, High= outliers exceeding high range values, Low= outliers below the low

range values).

Table 18. Number of nitrate range outliers as a function of depth in the Indian Ocean. (N= number of

observations, High= outliers exceeding high range values, Low= outliers below the low

range values).

Table 19. Number of nitrate range outliers as a function of depth in the Southern and Arctic Oceans.

(N= number of observations, High= outliers exceeding high range values, Low= outliers

below the low range values).

Table 20. Silicate ranges for the Atlantic Ocean as a function of depth.

Table 21. Silicate ranges for the Pacific Ocean as a function of depth.

Table 22. Silicate ranges for the Indian Ocean as a function of depth.

Table 23. Silicate ranges for the Southern and Arctic Oceans as a function of depth.

Table 24. Number of silicate range outliers as a function of depth in the Atlantic Ocean. (N= number

of observations, High= outliers exceeding high range values, Low= outliers below the low

range values).

Table 25. Number of silicate range outliers as a function of depth in the Pacific Ocean. (N= number

of observations, High= outliers exceeding high range values, Low= outliers below the low

range values).

Table 26. Number of silicate range outliers as a function of depth in the Indian Ocean. (N= number

of observations, High= outliers exceeding high range values, Low= outliers below the low

range values).

Table 27. Number of silicate range outliers as a function of depth in the Southern and Arctic Oceans.

(N= number of observations, High= outliers exceeding high range values, Low= outliers

below the low range values).

Table 28. Acceptable distances for "inside" and "outside" values used in the Reiniger-Ross scheme

for interpolating observed level data to standard levels.

Table 29. Number of observations interpolated from observed levels to standard levels using the

different interpolation schemes (numbers in parenthesis are percent of standard levels filled

using each method).

Table 30. Cruises flagged due to nitrate errors in the SD file (F.S.U. refers to the Former Soviet

Union).

v
Table 31. Cruises flagged due to silicate errors in the SD file (F.S.U. refers to the Former

Soviet Union).

Table 32. Number of flagged observations for each step of the quality control of phosphate data.

Table 33. Number of flagged observations for each step of the quality control of nitrate data.

Table 34. Number of flagged observations for each step of the quality control of silicate data.

Table 35. Number of profiles (N) containing observations flagged during the range check, and the

percentage of low and high outliers (% Low and % High) for each basin.

vi
LIST OF FIGURES

Figure 1. Seasonal distribution of (a) phosphate, (b) nitrate and (c) silicate profiles as a function of

year for each season.

Figure 2. Division of world ocean into individual basins.

Figure 3. Total number of (a) phosphate, (b) nitrate and (c) silicate observations for each basin used

in this study.

Figure 4a. Location of phosphate range check flags in the SD file

Figure 4b. Location of phosphate range check flags in the SD file

Figure 5. Total number of phosphate range outliers from the ranges check, and the number of values

above (high outliers) and below (low outliers) the ranges set for each basin used in this

sturdy.

Figure 6a. Location of nitrate range check flags in the SD file

Figure 6b. Location of nitrate range check flags in the SD2 file

Figure 7. Total number of nitrate range outliers from the ranges check, and the number of values

above (high outliers) and below (low outliers) the ranges set for each basin used in this

study.

Figure 8a. Location of silicate range check flags in the SD file

Figure 8b. Location of silicate range check flags in the SD2 file

Figure 9. Total number of silicate range outliers from the ranges check, and the number of values

above (high outliers) and below (low outliers) the ranges set for each basin used in this

study.

Figure 10a. Location of phosphate statistical check flags in the SD file

Figure 10b. Location of phosphate statistical check flags in the SD2 file

Figure 11. Phosphate outliers with depth from the standard deviation check

Figure 12a. Location of nitrate statistical check flags in the SD file

Figure 12b. Location of nitrate statistical check flags in the SD2 file

Figure 13. Nitrate outliers with depth from the standard deviation check

Figure 14a. Location of silicate statistical check flags in the SD file

Figure 14b. Location of silicate statistical check flags in the SD2 file

Figure 15. Silicate outliers with depth from the standard deviation check

vii
Figure 16a. Silicate annual mean at 1000 m depth (no check for unrealistic features)

Figure 16b. Silicate annual mean at 1000 m depth (after check for unrealistic features)

Figure 17a. Phosphate outliers from the unrealistic feature check of the SD file

Figure 17b. Phosphate outliers from the unrealistic feature check of the SD2 file

Figure 18a. Nitrate outliers from the unrealistic feature check of the SD file

Figure 18b. Nitrate outliers from the unrealistic feature check of the SD2 file

Figure 19. Silicate outliers from the unrealistic feature check of the SD file

viii
ACKNOWLEDGEMENTS

This work was made possible by a grant from the NOAA Climate and Global Change Program which

established a research group at the National Oceanographic Data Center to focus on the preparation of

research quality oceanographic data sets, objective analyses and diagnostic studies with these data sets.

Substantial amounts of historical oceanographic data used in this study were located and digitized with

support from several agencies. Data Archaeology and Rescue projects were supported with funding from

the NOAA Climate and Global Change Program, the NOAA Environmental Science Data ance

Information Management Program, the National Science Foundation, and the Office of Naval Research.

The data used are the master oceanographic data archives maintained by NODC/WDC-A as well as data

acquired as a result of the NODC Data Archaeology and Rescue (NODAR) project and the IODE/IOC

Global Oceanographic Data Archaeology and Rescue (GODAR) project. We would like to acknowledge

the scientists who have submitted their data to national and regional data centers and the data managers at

the various data centers.

We would like to thank Doug Hamilton and Linda Stathoplos for reviewing this manuscript.

ix
ABSTRACT

This paper is a description of the procedures used by the Ocean Climate Laboratory (OCL) in the quality

control of the historical oceanographic nutrient data archived at the National Oceanographic Data Center

(NODC). These procedures involve: (1) range checks of the observed level data for each major ocean

basin as a function of depth; (2) statistical check of the interpolated standard level data; and (3) a check

for unrealistic features after an initial computation of the objective analysis. Data were flagged along each

step of the quality control and the flagged data excluded from further checks. The flagged observed and

standard level data are available on CD-ROM.

INTRODUCTION

Oceanographers need quality data in order to understand the temporal and spatial variability of physical,

chemical and biological parameters in the oceans. A high quality database requires development of

procedures which insure the integrity of the data. The Ocean Climate Laboratory at the National

Oceanographic Data Center (NODC) is supported by the NOAA Climate and Global Change program to

produce scientifically quality controlled databases. This paper describes the quality control procedures

used to identify erroneous or non-representative measurements of phosphate, nitrate and silicate contained

in the NODC Oceanographic Station Data archives (SD file) plus additional data not yet archived (SD2

file).

Analysis of historical nutrient data involves combining data collected and processed using different

methodologies and precisions. Reliable methods for the measurement of low concentrations of nutrients

in seawater were not used until the 1920’s (Riley and Chester, 1971; Raymont, 1980). Historically,

nutrients have been measured manually using spectrophotometric methods such as those described by

Stricklan6 and Parsons (1972). These methods have generally been replaced by automated methods such

as the Technicon Autoanalyzer (Technicon Industrial Methods, 1969) and the chemiluminescence

analyzer for measuring nanomolar concentrations of nitrate (Garside, 1982). Further descriptions of

methods can be found in Wood et al. (1967), Technicon Industrial Methods (1969, 1972), Coote et al.

(1970, 1973), Stephens (1970), Atlas et al. (1971), Strickland and Parsons (1972), Pilson et al. (1973) and

Parsons et al. (1984). Sapozhnikov et al. (1988) describe the methods used in the Former Soviet Union

for the analysis of micronutrients as well as other seawater components.

A major concern is whether data collected using manual vs. automated methods can be combined into one

coherent dataset as is the case in the NODC SD file. A comparison study between automated and manual

methods based on the CSIRO Marine Laboratory data bank concluded there was good agreement between

the two methods for phosphate but not silicate or nitrate (Airey, 1987; Airey and Sandars, 1987). Further

investigation showed higher values in the manual measurement of nitrate between 1975-1984 were due to

incorrect use of the standard curve; the discrepancy in silicate results was due to the use of silicatecontaining artificial water in the preparation of the reagent blanks. Intercalibration experiments by the

International Council for the Exploration of the Seas (ICES) in the late 1960’s found the differences in

results between
laboratories due to problems in the standardization procedures (Koroleff et al.,1977).

In general, comparison between methods for all three nutrients show that results from both methods are

within the experimental deviations (Berberian and Barcelona, 1979; Airey and Sandars, 1987) except at

low concentrations where there is a loss of sensitivity in the automated methods. Berberian and Barcelona

(1979) conclude the advantage of the AutoAnalyzer methods (economy and speed of sample) make up for

the loss of sensitivity in low concentration areas.

The quality control of historical nutrient data was undertaken to prepare objective analysis maps of the

annual mean distribution of nutrients in the world oceans (Conkright et al., 1994).

DATA SOURCES AND DISTRIBUTIONS

The data used in this project are all the data found in the National Oceanographic Data Center’s archived

Oceanographic Station Data (SD file) as of the first quarter of 1993. Levitus and Gelfeld (1992) show

global distribution maps of the data held in this file for all years (1900-1992). In addition, data gathered

as a result of the NODC’s National Oceanographic Data Archaeology and Rescue (NODAR) and the

IODE/IOC Global Oceanographic Data Archaeology and Rescue (GODAR) projects were included in

this study. A description of the NODAR and GODAR projects can be found in Levitus et al (1994). The

NODAR and GODAR data sets are in a separate file named SD2 (since they have not yet been archived)

and will be referred to as such throughout the text. Data in the SD2 file includes the following:

1. Australian Station Data

2. German Station Data

3. Icelandic Station Data

4. ICES (International Center for the Exploration of the Sea) Station Data

5. Japanese NODC Station Data

6. Korean NODC Station Data

7. Combined Mediterranean Station Data

8. Miscellaneous ship of opportunity Station Data

9. Pacific Institute of Oceanology (Russia) South China Sea Station Data

10. SIO (Scripps Institute of Oceanography) Southtow cruise Station Data.

The unit used for nutrients is micromolar (μM).

Table 1 lists the number of phosphate, nitrate and silicate observations as a function of observed depth

levels for the combined SD and SD2 files. Shown in this table is the number of observed data points that

occur in the depth range centered around each standard level. The depth range for the sea surface is 0-5

m. At all other standard levels, the depth range is defined as the region between the midpoints of the

standard level being considered and the adjacent standard levels above and below. The standard levels

used in this study are listed in Table 1.

The terms "standard level data" and "observed level data" are required to understand the data distribution

and tables we present in this paper. We refer to the actual measured value of an in

2
situ oceanographic parameter as an "observation", and to the depth at which such a measurement was

made as "observed level depth". We may refer to such data as "observed level data". Before the advent

of oceanographic instrumentation that measure at high frequencies in the vertical, oceanographers often

attempted to make measurements at selected "standard levels" in the water column. For many analysis

purposes observed level data are interpolated to standard observation levels, if they do not occur exactly

at a standard observation level. The standard depths selected for this sturdy are listed in Table 1 and

include the 30 NODC standard depths and three additional levels at 3500, 4500 and 5500 meters depth.

Table 2 shows there are a total of 184,153 phosphate profiles, 75,403 nitrate profiles, and 110,413

silicate profiles. The greater number of samples for phosphate results from the fact that rapid and

accurate measurements of low nutrient concentrations phosphate were possible earlier for phosphate

than for nitrate and silicate (1920’s to early 1960’s). Rapid and convenient shipboard techniques for

nitrate measurements were not developed until 1963 (Morris and Riley, 1963). Global distribution maps

of these data are shown in Conkright et al. (1994). These maps are useful for identifying possible bias in

the data analysis due to missing data or few values.

The seasonal distribution of phosphate, nitrate and silicate profiles as a function of year is shown in Figs.

la, 1b and 1c respectively. These figures show possible bias in using an all-season database to examine

properties which have strong seasonal signals. For example, most expeditions to high latitudes are in the

summer season, so a bias towards low nutrient values (due to uptake by phytoplankton) is expected

when compositing these data. Nutrient measurements peaked during the mid-1960’s and early 1970’s,

particularly in the spring and summer months. Table 2 summarizes the number of profiles for each

season in the SD and SD2 files.

Because of differences in the horizontal and vertical distribution of nutrients in different ocean basins

(Levitus et al., 1993; Conkright et al., 1994), the oceans were divided into eleven separate basins as

shown in Fig. 2. Fig. 3 shows the total number of phosphate, nitrate and silicate observations in each of

these basins.

QUALITY CONTROL

The quality control procedures used by the NODC on the SD file parameters are described in the NODC

User’s Guide (1993). These procedures focus on problems such as valid ship speeds and correct latitudes

and longitudes. Quality control of the data is limited to determining consistency between related fields

(such as T-S diagrams) and range checking. The remainder of this paper will describe additional quality

control procedures applied to the NODC historical nutrient data by the NODC Ocean Climate

Laboratory. This is an ongoing and iterative process which will be updated as more data are incorporated

into the files and as a result of knowledge gained by this first pass through these procedures. These

methods apply to open ocean waters only and ignore coastal regions.

The additional steps used in the quality control (QC) of historical nutrient data are the following: (1)

preliminary QC; (2) range checks on the observed level data; (3) statistical checks on the

3
standard level data; and (4) unrealistic feature check based on the objectively analyzed data fields. Each

of these steps will be described in detail. The steps are cumulative: for each step of the QC process,

profiles or observations which fail a QC test are flagged and excluded from the next step in the procedure.

The flags identify the reason the profile or observation was excluded from further analysis. Rather than

delete erroneous or suspicious data, we simply tag them with a flag indicating they Have "failed" some

test. Each profile in our database is identified by a unique number, thus comments and discussion about

data flagged or otherwise is facilitated. Both the observed level and standard level profile data sets being

made available as a result of this project contain flags that indicate the status of various quality control

procedures. Appendix A contains a description of the various quality control flags used in this study.

A. Preliminary quality control

Preliminary check involves procedures common to all the SD and SD2 parameters such as a check for

duplicate depths, depth inversion checks, and duplicate profile checks. All data sets were checked against

themselves and other data sets to eliminate replicate profiles. A replicate profile is defined as a profile

which contains exactly the same information as another profile including position, date and parameter

values. The criteria for finding replicates was strict so as not to eliminate acceptable data. Two profiles

which appear to be duplicates may both bc saved if one profile contains interpolated data while the other

does not, or if one profile includes minutes in the latitude and longitude fields while a similar profile

canoes not. Approximately 20,000 duplicate profiles were identified in the NODC data base.

A depth inversion error occurs when a reading has a shallower depth than the reading directly above it. A

depth duplication is a reading which has the same depth as the reading above it. The second reading is the

flagged depth. If, after an inversion or duplication check, the next depth reading is still shallower than the

first reading, this and all subsequent depths are flagged. This usually occurs when two or more profiles

are entered together with no separating header information. A total of 10,202 profiles were flagged for

depth inversions or as depth duplicates.

B. Range check on the observed level data

Range checks screen the data for extreme minimum and maximum values. Coarse ranges were set for the

annual (ie. all-seasons) data as a function of depth (depths listed in Table 1) and basin (basins shown in

Fig. 2) for each parameter. The following steps were used to set the ranges:

(1) The first step was to examine the frequency distribution of values for each parameter. The observed

level data were first converted to the closest standard depth level in order to facilitate the computation of

the frequency distributions. The depth range for this conversion is determined as the region three-fourths

of the distance between the shallower standard level and the next deeper level. This depth conversion is

biased toward deeper values. For example, using standard level 26 (2000 m), the observed depths would

fall between 1812.5 m (3/4 of the distance between

4
levels 25 (1750 m) and 26) and 2125 m (1/4 the distance between levels 26 and 27 (2S00 m)). Initial

ranges were set to include values with a frequency greater than 0.5%. This approach leaches to very

4roac1 ranges in surface waters, narrowing down with increasing depths. Broad ranges were set since one

set of ranges was used for all seasons. Table 3 shows the percentage of phosphate values in the North

Pacific which fall within 15 phosphate class intervals as a function of depth. The shaded area represents

the range of acceptable phosphate values in the North Pacific as a function of depth.

(2) Statistical analysis of the data for each depth anti basin was performers to determine the mean and the

range of values which fall within one, two, and three standard deviations away from the mean. In most

cases, these results were used to set an upper limit of acceptable values.

(3) Comparison of the output from the frequency distribution and statistical analysis to literature values

and atlases primarily GEOSECS (Bainbridge, 1977; Craig et al., 1981, Spencer et al., 1982), Southern

Ocean Atlas (Gorcion et al., 1982), Wyrtki (1988) and Levitus et al. (1993) were used to set the final

ranges.

(4) Based on the results from steps 1-3, ranges were set and applied to the observed level data.

The following section will discuss the ranges set for each ocean basin, the location of the outliers, and the

number of outliers as a function of depth for each parameter in both the SD and SD2 files. An outlier is

defined as an observation or entire profile which is flagged because it failed a particular QC check. This

section will be lengthy since most of the observations were flagged by the range check. The defined

ranges are for open ocean waters and ignore coastal regions where the nutrient concentrations can greatly

exceed concentrations found in open ocean waters. Coastal areas are defined as any one-degree grid point

adjacent to a land grid point or any one-Degree grid point which Has a bottom depth of less than 200 m.

Unrealistic extreme ranges were set for coastal regions to avoid setting flags to these data. In some areas,

the range was not set high enough and data from coastal areas were flagged. In addition, no attempt was

made to set realistic ranges for waters below 5500 m depth because of lack of data (see Table 1).

(a) Phosphate

The ranges set for phosphate are presented in Tables 4-7 for each ocean basin as a function of depth. The

location of the outliers which result from these range checks are presented in Figs. 4a and 4b for the SD

and SD2 file. For the SD file, there are 9,254 profiles which contain observations that (to not fit within

the ranges defined, mostly in coastal regions. The SD2 file has 1,913 flagged observations, mostly in

coastal areas and the North and Equatorial Atlantic Oceans.

Fig. 5 and Tables 8-11 show the distribution of the outliers as a function of basin and depth. The

designation "High" refers to the number of observations which exceed the upper range limit, and "Low"

refers to those observations which have lower values than those listed in Tables 4-7. For phosphate, most

of the outliers are a result of extreme high values, particularly in the North and

5
Equatorial Atlantic, the South Pacific and the South Indian Oceans. Most of the high outliers are found in

the upper 300 m of the water column in the Atlantic and Pacific Oceans, and the upper 100 m for the

Indian Ocean. In contrast, most of the low outliers are found below 400 m except in the Equatorial Pacific

Ocean where they are below 200 m.

In addition, for depths below 5500 m, the phosphate upper limit was set at 6.0 μM. There are 118

observations exceeding this value.

(b) Nitrate

The ranges set for nitrate are listed in Tables 12-15 for each ocean basin. Note the minimum value for

nitrate was set at 0.01 μM to compensate for the fact that 0.0 appears to have been used as a missing

value by many investigators. Setting a minimum value of 0.01 μM also eliminates valid zero surface

water values. Procedures to identify valid zero values in the profiles containing nitrate data are underway.

The location of outliers from the nitrate range check is shown in Figs. 6a and 6b for the SD and SD2 files.

For the SD file, there are 9,352 profiles containing observations that do not fit within the ranges defined.

The SD2 file has 535 profiles containing outliers. Fig. 7 and Tables 16-19 show the distribution of the

outliers as a result of setting ranges as a function of basin and depth per basin. The upper range for waters

exceeding 5500 m depth was set at 60.0 μM, which results in 54 observations exceeding this value.

Unlike phosphate, most nitrate range outliers are due to the lower limit set, specifically setting the

minimum range value to 0.01 μM instead of zero in order to flag missing data values of zero. Tables 16-

19 show most "low" outliers are in the upper 50-100 m of the water column, particularly in the North

Pacific, Equatorial Indian and South Indian Oceans. Most observations exceeding the high range value

are also found in surface waters, particularly in the North and Equatorial Atlantic Oceans.

(c) Silicate

The ranges set for silicate are shown in Tables 20-23 for each ocean basin. The location of outliers which

result from the range check is shown in Figs. 8a and 8b for both the SD and SD2 files. For the Station

Data file, there are 11,464 profiles containing flagged observations. The SD2 file has 1,502 profiles

containing outliers. Most of these outliers are located around Australia and Japan. Fig. 9 and Tables 24-27

show the distribution of the outliers as a function of basin and depth. Most of the outliers are values

which exceed the limit set for silicate in all ocean basins. The high outliers are distributed with depth. The

low outliers are found at depths where the minimum range is no longer a zero value.

The deep water (> 5500 m depth) upper limit for silicate was set at 150 μM. There are 119 observations

which exceed this value.

6
C. Interpolation from observed to standard depth levels

Prior to the next step in the quality control, the data are interpolated from observed levels to standard

levels. The interpolation scheme used is a modification from that described by Reiniger and Ross (1968)

and noted by UNESCO (1991) as being in common usage. Their scheme uses four observed values

surrounding the standard level in question, the two closest shallower values and the two closest deeper

values. The closest shallower and deep values ("inside" values) and the two farthest shallow and deep

values ("outside" values) must be within the depth difference criteria shown in Table 28. The first set of

depths in this table is the maximum distance between the closest or "inside" observed reading depth. The

second set of depths applies to the maximum distances to the two observed levels further from the

standard level in question. This interpolation scheme has the advantage over three point Lagrangian

interpolation of being less susceptible to extremes when a large gradient is encountered since two separate

three-point Lagrangian interpolations are averaged and then fit to a reference curve.

If all the above criteria are met, the standard depth value is set by the Reiniger and Ross (1968)

interpolation. If there are not enough surrounding values within acceptable distances, three point

Lagrangian interpolation is performed on the value above and two values below the level in question or

on the two values above and one value below:

X(z) = x1

(z-z2)(z-z3)

(z1-z2)(z1-z3)

 + x2

(z-z1)(z-z3)

(z2-z1)(z2-z3)

 + x3

(z-z1)(z-z2)

(z3-z1)(z3-z2)

 (1)

where z1 ,z2, and z3 are the shallowest, middle and deepest observed depths respectively, z is the desired

level for interpolation, and x1 ,x2, and x3 are the values associated with the shallowest, middle and deepest

depths; X(z) is the interpolated value.

If there are insufficient data points to perform the above calculations, straight linear interpolation is used:

X(z) = x1 + 

(z-z1)

(z2-z1)

 * (x2-x1) (2)

where x1 and x2 are the observed data values, z1 and z2 are the shallowest and deepest depths, z is the

desired level for interpolation and X(z) is the desired interpolated value.

Modifications to the Reiniger and Ross (1968) method are the following:

1. If the Reiniger and Ross interpolated value does not fall between the observed values directly above

and below it, linear interpolation is substituted.

2. If any value is recorded within 5 meters of the surface, this value is directly used as the

7
surface value.

Some observed level data were "lost" in the interpolation process because they were too far from a

standard level (and therefore not used), or there were other closer observations available. A summary of

the number of observations which met the criteria for the different interpolation methods is presented in

Table 29. Direct substitution and the Reiniger and Ross interpolation account for most of the standard

level values.

D. Statistical analysis of data at standard depth levels

Once observed level data were interpolated to standard levels, the two data files, SD and SD2, were

merged and statistical checks were performed to flag data which exceeded the standard deviation criteria.

All non-flagged data were first averaged by five-degree-squares to produce the number of observations,

mean, and standard deviation for each square. Each five degree square box was designated coastal, near

coastal, or open ocean, depending on the number of one-degree by one-degree latitude-longitude

gridboxes in the five-degree box which were land (0 m depth) areas. Profiles were flagged if: (a) a fivedegree square containing a land point exceeded 5 standard deviations in the upper 50 m; (b) near-coastal

regions with values exceeding 4 standard deviations in the upper 50 m; (c) values exceeding three

standard deviations for all other data except when a profile was at or below the average depth level for the

one-degree box in which it was contained, or any of the adjacent one degree boxes, then 4 standard

deviations were used. The reason for varying the number of standard deviations allowed is the high

variability in shallow coastal areas due to river runoff, upwelling and other factors. High variability

within a five-degree box near the ocean bottom can occur if the five-degree square box contains portions

of two basins: i.e. the mid-Atlantic ridge separating east and west Atlantic waters. This check was only

performed if there were five or more profiles in the grid box. If more than two observations in a profile

exceeded the selected criteria, the profile was flagged and not included in further analysis.

The standard deviation check was applied twice to the data and then new five-degree square statistics

were computed to produce a new "clean" data set. Results from the standard deviation check show 5764

phosphate profiles containing outliers, 2105 nitrate profiles with outliers and 346S silicate outliers. The

number of outliers decreases rapidly as a function of depth. Figures 10-15 show the location of profiles

which were flagged during the statistical check for the SB and SD2 files and the distribution of these

outliers with depth.

Five-degree square statistics are an additional product from this analysis. The five-degree statistics

available are the number of observations, mean, and root-mean-square deviation.

K. Objective analysis

Following the statistical check, data were averaged by one-degree squares for input to the objective

analysis. The objective analysis is described by Levitus and Boyer (1994) and Conkright et al (1994).

After the initial objective analyses was computed for each standard

8
level, there were still erroneous values which resulted in rapid concentration changes within an area

appearing as a "bull’s-eye" or some other unrealistic feature. Figure 16a shows an unrealistic feature

("bullseye") still present after the range and statistical checks (Figure 16b shows the same figure after the

unrealistic features have been flagged). These features occur because of the difficulty in identifying nonrepresentative values in data sparse areas. Figures 17-19 show the location of data which were flagged

due to unrealistic or erroneous values found in contour plots of the initial objectively analyzed fields. All

these data were identified by investigating suspicious features and identifying the profile or individual

data points which created each unrealistic feature. In some cases, entire cruises were flagged. Tables 30

and 31 list the cruises which were flagged as containing unrepresentative data for nitrate and silicate

respectively. No cruises were flagged for phosphate. In addition, no cruises were flagged in the SD2 file.

SUMMARY AND FUTURE WORK

Tables 32, 33 and 34 list the total number of profiles containing flagged observations for each QC step.

The summary listed in these figures does not include the outliers from the preliminary check (duplicates,

depth errors, position errors). Most of the observations were flagged during the range check. Table 35 is a

summary of the number of profiles containing flagged observations from the range check of phosphate,

nitrate and silicate as a function of ocean basin. The majority of the outliers for phosphate and silicate

were observations exceeding the ranges set, unlike nitrate where the largest number of outliers were due

to zero values. As previously noted, the high percentage of low outliers for nitrate is due to using 0.01 μM

as a lower limit to avoid using missing values of zero as data. One reason for the large number of range

outliers is that the ranges set must include seasonal and geographical variability.

Future work will include the following:

(1) identify profiles where zero is used as a missing value and conversion to -99.999 as a new

missing value - this work is already in progress,

(2) develop ranges for each season at each basin as a function of depth,

(3) geographic expansion of the range definition process to include coastal regions and some of

the major inland seas such as the Mediterranean, Baltic and Black Sea,

(4) improve the vertical interpolation scheme by developing criteria for the depth of the "inner"

points based on the geographical location of the profile as well as the time of year,

(5) incorporate feedback from data managers and scientists who have utilized the data sets

distributed by the NODC and have identified additional problems with the data.

The flagged observed and standard level data used in this study and in the preparation of the World Ocean

Atlas 1994, Volume 1: Nutrients (Conkright et al., 1994) are available on CD-ROM. Appendix 1 is a

description of the flags used to identify erroneous data in the SD and SD2 files. Appendix 2 is a sample

program which reads the CD-ROM data. A sample output of the flagged observed level nutrient data is

shown in Appendix 3.

In addition to the observed and standard level data, one-degree latitude-longitude objective

9
analyzed values for phosphate, nitrate and silicate and five-degree square statistics will be available on

CD-ROM. The one-degree and five-degree horizontal co-ordinate systems used for the analyzed fields are

shown in Appendices 4 and 5. The data on the CD-ROM are sorted using the geographic grid numbering

system of World Meteorological Organization (WMO) where ten-degree by ten-degree latitude-longitude

squares are assigned a unique number (WMO squares are shown in Appendix 6).

10
REFERENCES

Airey, D. 1987. Errors in the values for nitrate and silicate concentrations in seawater, as listed in the

CSIRO and world data banks. CSIRO Mar. Lab. Report 181, 18 pps.

______ and G. Sandars. 1987. Automated Analysis of Nutrients in Seawater. CSIRO Mar. Lab. Report

166, 95 pps.

Atlas, E. L., S. W. Hager, L. I. Gordon and P. K. Park. 1971. A practical manual for use of theTechnicon

Autoanalyzer in seawater nutrient analyses; revised. Oregon State Univ. Tech.Rep., 215 pps.

Bainbridge, A. E. 1977. GEOSECS Atlantic Expedition, Vol. 2, Sections and Profiles. U.S.Government

Printing Office, Washington, D.C., 198 pps.

Berberian, G. A. and M. Barcelona. 1979. Comparison of Manual and Automated Methods of Inorganic

Micro-Nutrient Analysis. NOAA Tech. Mem. ERL AOML-40, 26 pps.

Conkright, M.E., S. Levitus and T. Boyer. 1994. World Ocean Atlas 1993, Vol 1: Nutrients.NOAA Atlas

Series. National Oceanic and Atmospheric Administration, Washington,B.C. In press.

Coote, A. R., C.R. Mann, A. Walton and J.M. Edmond. 1973. A correction to CIRCE silicate values for

the South Atlantic; comparison with HUDSON-70 silicates. Deep-Sea Res. 20: 579-581.

_______, I.W. Duedall and R.S. Hiltz. 1970. Automatic Analysis at sea. Industrial Analysis. Technicon

International Congress: Advances in Automated Analysis Vol 2. Thurman Assoc. Publ. pps. 347-

351.

Craig, H., W. S. Broecker and D. Spencer. 1981. GEOSECS Pacific Expedition, Vol. 4, Sections and

Profiles. U.S. Government Printing Office, Washington, D.C., 251 pps.

Garside, C. 1982. A chemiluminescent technique for the determination of nanomolar concentrations of

nitrate and nitrite in seawater. Mar. Chem. 11: 159-167.

Gordon, A. L., E.J. Molinelli, and T.N. Baker. 1982. Southern Ocean Atlas. Columbia Univ.Press, New

York, 266 pps.

Koroleff, F., K.H. Palmork, O. Ulltang and J.M. Gieskes. 1977. The International Intercalibration

Exercise for Nutrient Methods. ICES/SCOR Cooperative Research Report

67, 44 pps.

Levitus, S. and T. Boyer. World Ocean Atlas 1994, Vol 2: Oxygen. 1994. NOAA Atlas Series, National

Oceanic and Atmospheric Administration, Washington, D.C. In preparation

11
________, R. Geldfeld, T. Boyer and D. Johnson. 1994. Results of the NODC Oceanographic Data

Archaeology and Rescue Projects. Key to Oceanographic Records Documentation No. 19, NODC,

Washington, B.C.

________, M. E. Conkright, J.L. Reid, R. Najjar and A. Mantyla. 1993. Distribution of nitrate, phosphate

and silicate in the world ocean. Progr. Oceanogr. 31: 245-273.

_________ and R. Geldfeld. 1992. National Oceanographic Data Center Inventory of Physical

Oceanographic Profiles - Global Distributions by Year for All Countries. Key to Oceanographic

Records Documentation No. 18, NODC, Washington, D.C., 242 pps.

_________ 1982. Climatological Atlas of the World Ocean. NOAA Professional Paper 13, Rockville,

Md, 173 pps.

Morris, A.W. and J.P. Riley. 1963. The determination of nitrate in sea-water. Analytica Chim. Acta 29:

272-279.

NODC. 1993. National Oceanographic Data Center User’s Guide. National Oceanic and Atmospheric

Administration, Washington, D.C. Key to Oceanographic Records Documentation No. 18, NODC,

Washington, D.C.

Parsons, T.R., Y. Maita and C.M. Lalli. 1984. A Manual of Chemical and Biological Methods for

Seawater Analysis. Pergamon Press, New York, 173 pps.

Pilson, M.E.Q., K.A. Fanning and K. Hinga. 1973. The Determination of Dissolved Silica. Graduate

School of Oceanography, Univ. Rhode Island, 12 pps.

Raymont, J.E.G. 1980. Plankton and Productivity in the Oceans Volume 1 - Phytoplankton. Pergamon

Press, New York, 489 pps.

Reiniger, R. F. and C.K. Ross. 1968. A method for interpolation with application to oceanographic data.

Deep-Sea Res. 15: 185-193.

Riley, J.P. and R. Chester. 1971. Introduction to Marine Chemistry. Academic Press, New York, 46S pps.

Sapozhnikov, V.V., A.I. Agatova, N.V. Arzhanova, I.A. Naletova, N.V. Mordasova, V.L. Zubarevich,

S.S. Vladimirskij, N.I. Torgunova and A.I. Bondarenko. 1988. Methods oils hydrochemical

analysis of the major nutrients. VNIRO, MOSCOW (USSR), 119 pps.

Spencer, D., W.S. Broecker, H. Craig and R.F. Weiss. 1982. GEOSECS Indian Ocean Expedition, Vol. 6,

Sections and Profiles. U.S. Government Printing Office, Washington, B.C., 140 pps.

Stephens, K. 1970. Automated measurement of dissolved nutrients. Deep-Sea Res. 11: 393-396.

12
Strickland, J. D. H. and T.R. Parsons. 1972. A practical handbook of seawater analysis. Fisheries

Research Board of Canada Bull. No. 167, 310 pps.

Technicon Industrial Methods. 1972. Autoanalyzer II. Technicon Instruments Corp., Tarrytown, New

York.

Technicon Industrial Methods. 1969. Ortho-phosphate in seawater, 36-69W; Silicate in Seawater, 57-

70W . Technicon Instruments Corp., Tarrytown, New York.

UNESCO. 1991. Processing of Oceanographic Station Data. Imprimerie des Presses Unibversitaires de

France, Vendome, 138 pps.

Wood, E. D., F.A.J. Armstrong and F.A. Richards. 1967. Determination of nitrate in seawater by

cadmium-copper reduction to nitrite. J. Mar. Biol. Assoc. V.K. 47: 23.

Wyrtki, K. 1971. Oceanographic Atlas of the International Indian Ocean Expedition. National Science

Foundation, Washington, B.C., 531 pps.

13
APPENDIX 1. DATA FLAGS AND DATA AVAILABILITY

The flagged observed and standard level nutrient profiles are available from the National

Oceanographic Data Center on CD-ROM, exabyte tape and other media. Data were flagged at

each quality control step and the flagged data excluded from further checks. The flags were added

to the header data (0 for a good profile and 1 if the entire profile was excluded from further quality

control) and for each parameter at every depth in the profile. The following is a description of the

flags which are used to identify errors in the nutrient data.

A. Depth error flags

If the second of two successive depths is shallower than the first (a depth inversion), the second

depth is marked with a flag value = 1. Each depth following the second depth, which is also

shallower than the first depth is flagged with a value = 1. If three successive depths are shallower

than the first depth, every depth reading following the first will be marked with a value = 1.

Likewise, if two successive depth readings are equal, the second reading will be marked with a

value = 1. All useable depths are marked with a value = 0.

B. Profile error flags

Flags on all values of an individual parameter in a profile as well as flags applied to individual

observations of a parameter pertain to the quality control done to create the analyzed fields

(climatologies). Standard deviation checks are done only on standard level data. This check

calculates the mean and standard deviation of each parameter for 5 degree square latitude

longitude boxes and flags values which are more than 3-5 standard deviations from the mean. (3

for open ocean, 5 for coastal, 4 for near coastal.) If a profile contains two or more standard

deviation failures, the whole profile is flagged. This is done for annual (all parameters), seasonal

(temperature, salinity, oxygen) and monthly (temperature, salinity) periods. Density stability

checks are only for temperature and salinity profiles. The criteria for an instability is described by

Levitus (1982). Two or more instabilities cause a profile to be flagged. Although stability checks

are performed on standard level data, the observed profile is flagged as follows. While observed

level density inversions are flagged at individual depths, no observed level profiles were flagged

for having two or more inversions, this flag although included in observed level whole profile

flag, pertains to the standard level profile. Flags such as Density and temperature inversions are

placed at both observed and standard levels. The cruise flag denotes a cruise with consistently

anomalous data. Bullseye flags apply to depths with anomalous data which cause ripple effects, or

bullseyes in analyzed data.

14
C. Definition of Flags

(1) FLAGS FOR ENTIRE PROFILE (AS A FUNCTION OF PARAMETER)

0 - accepted profile

1 - failed annual standard deviation check

2 - two or more density inversions (Levitus, 1982 criteria)

3 - flagged cruise

4 - failed seasonal standard deviation check

5 - failed monthly standard deviation check

6 - flag 1 and flag 4

7 - flag 1 and flag 5

8 - flag 4 and flag 5

9 - flag 1 and flag 4 and flag 5

(2) FLAGS ON INDIVIDUAL OBSERVATIONS

(a) Depth Flags

0 - accepted value

1 - error in recorded depth (same or less than previous depth)

2 - temperature inversion of magnitude > 0.3o/meter

3 - temperature gradient of magnitude > 0.7o/meter

4 - temperature gradient and inversion

(b) Observed Level Flags

0 - accepted value

1 - range outlier (outside of broad range check

2 - density inversion

3 - failed range check and density inversion check

(3) Standard Level Flags

0 - accepted value

1 - bullseye marker

2 - density inversion

3 - failed annual standard deviation check

4 - failed seasonal standard deviation check

5 - failed monthly standard deviation check

6 - failed annual and seasonal standard deviation check

7 - failed annual and monthly standard deviation check

8 - failed seasonal and monthly standard deviation check

9 - failed annual, seasonal and monthly standard deviation check

15
APPENDIX 2. FORTRAN PROGRAM TO READ AND WRITE OBSERVED LEVEL AND

STANDARD LEVEL VERTICAL PROFILE DATA

program OCLdemo

c program to print out 20 profiles for all parameters in one record

c from NODC’s Ocean Climate Laboratory quality controlled ASCII observed level

c or standard level data

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

c HEADER INFORMATION:

c

c cc - NODC country code, see country code list

c icruise - NODC cruise code (NODC files only)

c rlat - latitude in degrees down to thousandths

c rlon - longitude in degrees <town to thousandths

c NOTE: negative latitudes are south, negative longitudes are west

c iyear - year of profile

c month - month of profile

c iday - day of profile

c ctime - 6 characters representing GM time

c in hours, r3own to thousandths

c blanks mean time not recorded

c nprofile - OCL profile number

c numlevels - number of recorded levels

c isoor - 1 for standard levels 0 for observed levels

c nparm - number of parameters recorded in this entry

c

c PARAMETER FILE INFORMATION

c newfile - FORTRAN file number

c data - data array

c depth - observed depths

c maxlevel - maximum number of levels (6000)

c maxparm - maximum number of parameters (15)

c ierror - flag for all parameter values in a profile

c iderror - individual depth parameter flags

c ip2 - parameter codes

c

c These are the codes presently used

c PARAMETER # CODE

c Temperature 1

c Salinity 2

c Oxygen 3

c Phosphate 4

16
c TotalPhos 5

c Silicate 6

c Nitrite 7

c Nitrate 8

c pH 9

c

c bmiss - missing value indicator

c amiss - ASCII missing value indicator

c ieof - end of file marker (1 if end of file reached, otherwise 0)

c nfile, ifile - input and output files

c

ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

c

parameter maxleve1=6000, maxparm=15, kdim=33 parameter bmiss=-

1.E10, amiss=-99.99

c

character*2 cc

character*6 ctime

character*80 nfile, ifile

character*4 param(9)

c

dimension data(maxlevel,maxparm), depth(maxlevel),dz(kdim) dimension

ierror(maxparm),iderror(maxleve1,0:maxparm) dimension ip3(0:maxparm)

C

data dz/ 0., 10., 20., 30., 50., 75., 100., 125., 150.,

* 200., 250., 300., 400., 500., 600., 700., 800., 900.,

* 1000., 1100., 1200., 1300., 1400., 1500., 1750., 2000.,

* 2500., 3000., 3500., 4000., 4500., 5000., 5500./

c

data param/’Temp’,’Sal’,’02’,’PO4’,’tP’,’Si’,’NO2’,’NO3’,’ph’/

c

c Read and open input data file name

c

write(6,*) ’Input File Name’

read(5,’(a80)’) nfile

newfile=11 open(newfile,file=nfile,status=’old’)

c

c Read and open output file name

c

write(6,*) ’Input Output File Name’ read(5,’(a80)’)

ifile open(12,file=ifile,status=’unknown’)

C

c Begin loop to read and write 20 profiles

17
do 50 ij=1,20

c

c Call subroutine to read data

C

call OCLread(cc,icruise,rlat,rlon,iyear,month,

* iday,ctime,jjx,numlevels,isoor,nparm,newfile,data,

* depth,maxlevel,maxparm,ierror,iderror,ip3,bmiss,ieof)

c

c end of file statement

if ( ieof.gt.0 ) goto 4

C

c Read in depths if standard level data (isoor .eq. 1)

C

if ( isoor.eq.l.and.ij.eq.1) then

do 60 i=l,kdim

60 depth(i) =dz(i)

endif

C

c Write out header information to file

c

write(12,799)

write(12,800) cc,icruise,rlat,rlon,iyear,month,iday,

* ctime,jjx,numlevels,(ierror(np),np= 1,nparm)

799 format(’cc’,3x,’cruise’,4x,’lat’,Sx,’lon’,3x,’year’,1x,’mm’,1x, ’dd’,2x,’

* GMT’,3x,’profile’,1x,’depths’,2x,’flag’)

800 format(a2,1x,i8,1x,f7.2,1x,f8.2,2x,i4,1x,i2,1x,i2,

* 1x,a5,1x,i8,1x,i4,4x,i1)

c

c Write subtitle (depth, parameter, flag) to file

c

write(12,801)(param(ip3(mm)), mm=1,nparm)

801 format(2x,’Depth’,1x,’F’,10(4x,a4,1x,’F’))

C

c Write data to file

do 80 n=l,numlevels

write(12,802) depth(n),iderror(n,0),

* (data(n,ip3(j)),iderror(n,ip3(j)),j= 1,nparm)

80 continue

802 format(1x,f6.0,1x,i1,2x,10(f6.2,1x,i1,2x))

c

write(12,’(/)’)

c

50 continue

4 continue

C

stop

18
end

c

c

cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

subroutine OCLread(cc,icruise,rlat,rlon,iyear,month,

* iday,ctime,nprofile,numlevels,isoor,nparm,newfile,data,

* depth,maxlevels,maxparm,ierror,iderror,ip2,bmiss,ieof)

c

c subroutine to read OCL ascii format

c

c

parameter amiss=-99.99

character cc*2, cholder*80, ctime*6

c

dimension data(maxlevels,maxparm),iderror(maxlevels,O:maxparm) dimension

depth(maxlevels),ierror(maxparm),ip2(0:maxparm)

c

c read in header

if ( ieof .1t. 1 ) then

read(newfile,800,end=4) cc,icruise,rlat,rlon,iyear,month,iday,

* ctime,nprofile,numlevels,isoor,nparm,(ip2(i),ierror(ip2(i)),

* i=l,nparm)

c

800 format(a2,i5,f7.3,f8.3,i4,i2,i2,a6,i8,i3,il,i2,10(i2,i1))

c

c calculate how many lines this profile occupies

c

isoor2=0

iaddline=0

if ( isoor.eq.0 ) isoor2=1

nlines= ((nparm+isoor2)*numlevels)

if ( mod(nlines,10) .gt. 0 ) iaddline=1

nlines=(nlines/10)+iaddline

c

c read in data

c

levels=0

mread=nparm

iend=0

c

do 40 1=1,nlines

read(newfile,’(a80)’) cholder

c

19
do 45 n=1,10 m2=(n-1)*8+1

if ( mread .eq. nparm ) then

c

if ( levels .eq. numlevels ) then

iend=1

else

levels=levels+1

unread=0

idp=1

endif

endif

c

if ( iend .1t. 1 ) then

c

if ( idp .eq. 1 .and. isoor .eq. 0 ) then

read(cholder(m2:m2+7),’(f7.2,i1)’)

depth(levels),iderror(levels,0)

idp=0

else

mread = mread + 1

read(cholder(m2:m2+7),’(f7.3,i1)’)

data(levels,ip2(mread)),iderror(levels,ip2(mread))

c

if ( data(levels,ip2(mread)).lt.amiss+1. )

data(levels,ip2(mread)) = amiss

if ( data(levels,ip2(mread)).eq.bmiss)

data(levels,ip2(mread)) = amiss

endif

endif

c

45 continue

40 continue

c

endif

c

return

c

4 ieof = 3.

return

c

end

20
APPENDIX 3. SAMPLE OUTPUT OF OBSERVED LEVEL NUTRIENT DATA

cc cruise lat long year mm dd GMT profile depths flag

46 0 64.67 -27.60 1965 5 9 20.00 28333 14 0

Depth F PO4 F Si F NO3 F

0. 0 -99.99 0 4.90 0 11.20 0

10. 0 0.78 0 6.10 0 11.20 0

20. 0 0.77 0 6.10 0 11.60 0

30. 0 0.88 0 6.30 0 11.70 0

50. 0 0.77 0 6.10 0 11.60 0

75. 0 0.86 0 6.30 0 11.30 0

100. 0 0.79 0 6.30 0 12.00 0

200. 0 0.93 0 6.10 0 12.00 0

300. 0 0.91 0 6.50 0 11.90 0

400. 0 0.82 0 6.80 0 11.70 0

500. 0 -99.99 0 -99.99 0 -99.99 0

500. 1 0.96 0 5.90 0 12.30 0

600. 0 0.97 0 7.80 0 12.50 0

690. 0 -99.99 0 6.10 0 12.90 0

21
Appendix 4. One-degree horizontal co-ordinate system of the

analyzed fields

Each element of F(i,j) of an analyzed field F, where F is dimensioned F(360,180), is

considered to represent the value at the center of a one degree latitude- longitude

square

Longitude denoted by the variable "i", varies from 1 at 0.5 o E to 360 at 0.5oW

Latitude denoted by the variable "j", varies from 1 at 89.5 o S to 180 at 89.5o M

The point F(1,1) is the value at 0.5 oE, 89.5oW

The point F(218,20) is the value at 142.5oW, 70.5oS

The point F(360,91) is the value at 0.5oW, 0.5oN

22
Appendix 5. Five-degree horizontal co-ordinate system

of the analyzed fields

Each element of F(i,j) of an analyzed field F, where F is

dimensioned F(72,36), is considered to represent the value at the

center of a five degree latitude- longitude square

Longitude denoted by the variable "i", varies from 1 at 2.5 o

E to 72 at 2.5oW

Latitude denoted by the variable "j", varies from 1 at 87.5 o

S to 36 at 87.5o N

23
24
Table 1. Distribution with depth of phosphate, nitrate and silicate observations.

Depth Phosphate Nitrate Silicate

0 173484 68007 102890

10 156184 58789 88090

20 153475 61565 90865

30 144104 54897 82806

50 141130 53233 81579

75 116268 42701 65280

100 109022 41439 63678

125 93489 35670 54611

150 91286 35140 54410

200 81583 32028 47732

250 78056 29152 45471

300 75242 27988 42831

400 72411 26119 41625

500 64095 24395 37068

600 57649 19379 33317

700 53901 17684 31518

800 52163 17247 30347

900 50185 16152 29543

1000 47346 15403 27823

1100 39978 13200 23562

1200 36291 12343 21800

1300 32497 11167 19979

1400 29814 9949 18772

1500 26435 9238 16688

1750 21629 7765 13187

2000 18108 6679 11342

2500 11872 5712 8907

3000 9038 4424 6989

3500 7392 3618 5669

4000 5175 2937 4304

4500 3254 2036 2951

5000 1627 1096 1465

5500 562 397 497

25
Table 2. Number of phosphate, nitrate and silicate profiles for each season in the

SD and SD2 files

Season Phosphate Nitrate Silicate

SD SD2 SD SD2 SD SD2

Winter

(Jan-Mar)

35411 7442 15301 2518 20248 5199

Spring

(Apr-Jun)

43927 7169 18576 4021 24756 6619

Summer (JulSep)47794 6707 18429 2405 27285 5196

Fall

(Oct-Dec)

29061 6642 12123 2030 16425 4685

Total

profiles/file

156193 27960 64429 10974 88714 21699

Total

Profiles

184153 75403 110413

26
27
Table 4: Phosphate ranges for the Atlantic Ocean as a function of depth

Depth North Atlantic Eq. Atlantic South Atlantic

Low High Low High Low High

0 0.0 1.4 0.0 1.0 0.0 2.0

10 0.0 1.4 0.0 1.0 0.0 2.0

20 0.0 1.4 0.0 1.2 0.0 2.0

30 0.0 1.4 0.0 1.4 0.0 2.0

50 0.0 2.0 0.0 2.0 0.0 2.0

75 0.0 2.0 0.0 2.4 0.0 2.4

100 0.0 2.0 0.0 2.4 0.0 2.4

125 0.0 2.0 0.0 2.8 0.0 2.4

150 0.0 2.0 0.0 2.8 0.0 2.4

200 0.0 2.4 0.0 2.8 0.0 2.8

250 0.0 2.4 0.0 3.2 0.0 2.8

300 0.0 2.4 0.0 3.2 0.0 2.8

400 0.0 3.2 0.0 3.6 0.2 3.2

500 0.0 3.2 0.0 3.6 0.2 3.2

600 0.0 3.2 0.0 3.6 0.2 3.2

700 0.2 3.2 0.2 3.6 0.2 3.2

800 0.2 3.2 0.2 3.6 0.2 3.2

900 0.2 3.6 0.3 3.6 0.2 3.2

1000 0.2 3.6 0.3 3.6 0.4 3.2

1100 0.2 3.6 0.3 3.6 0.4 3.2

1200 0.2 3.6 0.3 3.6 0.4 3.2

1300 0.2 3.6 0.3 3.6 0.4 3.2

1400 0.2 3.6 0.6 3.2 0.4 3.2

1500 0.2 3.6 0.6 3.2 0.4 3.6

1750 0.2 3.6 0.6 3.2 0.4 3.6

2000 0.2 3.6 0.3 3.2 0.4 3.6

2500 0.2 3.4 0.3 3.2 0.4 3.6

3000 0.2 3.4 0.3 3.2 0.4 3.6

3500 0.2 3.4 0.3 3.2 0.6 3.2

4000 0.4 3.2 0.5 3.2 0.6 3.2

4500 0.4 3.2 0.6 2.8 0.6 3.2

5000 0.4 2.8 0.6 2.8 0.8 2.8

5500 0.4 2.8 0.6 2.8 0.8 2.8

28
Table 5. Phosphate ranges for the Pacific Ocean as a function of depth.

Depth North Pacific Eq. Pacific South Pacific

Low High Low High Low High

0 0.0 2.0 0.0 2.0 0.0 1.6

10 0.0 2.0 0.0 2.0 0.0 1.6

20 0.0 2.0 0.0 2.0 0.0 1.6

30 0.0 2.0 0.0 2.0 0.0 1.6

50 0.0 2.4 0.0 2.4 0.0 2.0

75 0.0 2.8 0.0 2.8 0.0 3.2

100 0.0 2.8 0.0 2.8 0.0 3.2

125 0.0 3.2 0.0 3.2 0.0 3.2

150 0.0 3.2 0.0 3.2 0.0 3.2

200 0.0 3.6 0.2 3.2 0.0 3.2

250 0.0 3.6 0.4 3.2 0.0 3.2

300 0.0 3.6 0.6 3.2 0.0 3.2

400 0.0 3.6 0.6 3.6 0.4 3.6

500 0.2 3.6 0.8 3.6 0.4 3.6

600 0.2 3.6 0.8 3.8 0.8 3.8

700 0.8 3.6 0.8 3.8 0.8 3.8

800 0.8 3.8 0.8 3.8 0.8 3.8

900 0.8 3.8 0.8 3.8 0.8 3.8

1000 0.8 3.8 0.8 3.8 0.8 3.8

1100 0.8 3.8 0.8 3.8 0.8 3.8

1200 0.8 3.8 0.8 3.8 0.8 3.6

1300 0.8 3.8 0.8 3.8 0.8 3.6

1400 0.8 3.6 0.8 3.8 0.8 3.6

1500 0.8 3.6 0.8 3.6 0.8 3.6

1750 0.8 3.6 0.8 3.6 0.8 3.6

2000 0.8 3.6 0.8 3.6 0.8 3.6

2500 0.8 3.6 0.8 3.6 0.8 3.6

3000 0.8 3.6 0.8 3.6 0.8 3.2

3500 0.8 3.2 0.8 3.2 0.8 3.2

4000 0.8 3.2 0.8 3.2 0.8 3.2

4500 0.8 3.2 0.8 3.2 0.8 3.2

5000 0.8 3.2 0.8 3.2 0.8 3.2

5500 0.8 3.2 0.8 3.2 0.8 3.2

29
Table 6. Phosphate ranges in the Indian Ocean as a function of depth.

Depth North Indian Eq. Indian South Indian

Low High Low High Low High

0 0.0 1.4 0.0 1.0 0.0 2.0

10 0.0 1.4 0.0 1.0 0.0 2.0

20 0.0 1.4 0.0 1.0 0.0 2.0

30 0.0 1.6 0.0 1.0 0.0 2.0

50 0.0 2.0 0.0 1.2 0.0 2.0

75 0.0 2.8 0.0 2.0 0.0 2.0

100 0.0 3.6 0.0 2.4 0.0 2.0

125 0.0 3.6 0.0 2.4 0.0 2.4

150 0.0 3.6 0.0 2.8 0.0 2.4

200 0.6 3.6 0.4 2.8 0.0 2.4

250 0.6 3.6 0.4 2.8 0.0 2.4

300 0.6 3.6 0.4 2.8 0.0 2.8

400 0.6 3.6 0.4 3.2 0.0 2.8

500 0.8 3.8 0.4 3.2 0.0 2.8

600 0.8 3.8 0.4 3.6 0.0 3.2

700 0.8 3.8 0.4 3.6 0.2 3.2

800 0.8 3.8 0.4 3.8 0.4 3.2

900 0.8 3.8 0.4 3.8 0.4 3.2

1000 0.8 3.8 0.4 3.8 0.4 3.2

1100 0.8 3.8 0.6 3.8 0.4 3.2

1200 0.8 3.8 0.6 3.8 0.4 3.2

1300 0.8 3.8 0.8 3.8 0.4 3.2

1400 0.8 3.8 0.8 3.6 0.4 3.2

1500 0.8 3.8 0.8 3.6 0.4 3.2

1750 0.8 3.8 0.8 3.6 0.4 3.2

2000 0.8 3.8 0.8 3.6 0.4 3.2

2500 0.6 3.8 0.8 3.6 0.4 3.2

3000 0.6 3.6 0.8 3.2 0.4 3.2

3500 0.6 3.6 0.8 32 0.4 3.2

4000 0.6 2.8 0.8 3.2 0.4 3.2

4500 0.6 2.8 0.8 3.2 0.4 3.2

5000 0.6 2.8 0.8 3.2 0.8 3.2

5500 0.6 2.8 0.8 3.2 0.8 3.2

30
Table 7. Phosphate ranges for the Southern and Arctic Oceans as a function of depth.

Depth Southern Ocean Arctic 0cean

Low High Low High

0 0.2 2.8 0.0 1.4

10 0.2 2.8 0.0 2.0

20 0.2 2.8 0.0 2.4

30 0.2 2.8 0.0 2.8

50 0.2 2.8 0.0 2.8

75 0.2 2.8 0.0 2.8

100 0.2 3.2 0.0 2.8

125 0.4 3.2 0.0 2.8

150 0.4 3.2 0.0 2.8

200 0.4 3.2 0.0 2.8

250 0.6 3.2 0.0 2.8

300 0.6 3.2 0.0 2.8

400 0.6 3.2 0.0 2.8

500 0.6 3.2 0.0 2.8

600 0.6 3.2 0.0 3.2

700 0.6 3.2 0.2 3.2

800 0.6 3.2 0.4 3.8

900 0.6 3.2 0.4 3.8

1000 0.6 3.2 0.4 3.8

1100 0.6 3.2 0.4 3.8

1200 0.6 3.2 0.4 3.8

1300 0.6 3.2 0.4 3.8

1400 0.8 3.2 0.4 3.8

1500 0.8 3.2 0.4 3.8

1750 0.8 3.2 0.4 3.8

2000 0.8 3.2 0.4 3.8

2500 0.8 3.2 0.4 3.8

3000 0.8 3.2 0.6 3.6

3500 0.8 3.2 0.6 3.6

4000 0.8 3.2 0.6 3.2

4500 0.8 3.2 0.6 2.8

5000 0.8 3.2 0.6 2.8

5500 0.8 2.8 0.6 2.8

31
Table 8. Number of phosphate range outliers as a function of depth in the Atlantic Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Atlantic Equatorial Atlantic South Atlantic

 Depth N High Low N High Low N High Low

 0 18376 632 0 4284 246 0 3,511 29 0

 10 13835 523 0 3026 175 0 2,274 23 0

 20 12073 515 0 2972 128 0 2,655 32 0

 30 11328 519 1 3828 120 0 2,790 21 0

 50 17006 287 0 4639 55 0 3,410 43 0

 75 13310 268 0 4429 44 0 2,282 10 0

 100 15664 245 0 4095 55 0 2,700 15 0

 125 5300 107 0 1785 18 0 770 3 0

 150 12030 238 0 3395 39 0 2 130 16 0

 200 11910 129 0 3602 42 0 2,824 9 0

 250 8517 107 0 2108 15 0 1,489 1 0

 300 12009 173 0 3455 34 0 2,337 13 0

 400 12048 20 0 3512 25 0 2,850 6 32

 500 11491 23 0 3200 22 0 2,287 12 19

 600 6939 14 0 2210 34 0 2,249 13 14

 700 4132 15 207 1451 24 9 1,688 13 21

 800 8785 48 277 1818 31 18 1,742 10 24

 900 3491 21 126 1052 19 6 1,204 6 11

 1000 8142 30 241 1541 14 13 1,500 11 32

 1100 2356 23 71 866 9 7 911 11 13

 1200 3890 20 151 910 3 12 1,038 7 26

 1300 1603 9 51 519 0 6 642 2 14

 1400 1977 4 43 633 4 12 845 3 10

 1500 5303 22 154 1147 6 41 1,322 2 20

 1750 2992 1 56 817 3 11 1,111 1 5

 2000 6589 1 139 1243 3 14 1,644 0 15

 2500 3433 2 44 880 1 11 1,758 1 2

 3000 2373 4 35 724 1 7 1,551 0 2

 3500 1675 0 26 587 2 3 1,347 3 7

 4000 1399 3 31 521 8 2 1,106 0 3

 4500 1129 4 13 385 10 0 803 0 4

 5000 733 3 7 205 4 0 484 1 0

 5500 220 5 0 74 1 0 164 0 0

32
 Table 9. Number of phosphate range outliers as a function of depth in the Pacific Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Pacific Equatorial Pacific South Pacific

 Depth N High Low N High Low N High Low

 0 24330 300 0 6439 118 0 5,033 471 0

 10 20273 252 0 4325 88 0 2,795 427 0

 20 17498 254 0 4598 109 0 3,742 444 0

 30 17860 278 0 3806 128 0 2,623 434 0

 50 25192 160 0 6305 76 0 4,345 326 0

 75 22379 57 0 6026 23 0 3,592 7 0

 100 22754 96 0 6487 26 0 3,787 16 0

 125 13424 19 0 4923 3 0 1,670 3 0

 150 22068 76 0 7916 6 0 3,569 17 0

 200 23285 34 0 8129 8 120 3,940 10 0

 250 14065 17 0 6609 6 90 2,345 Q 0

 300 19817 37 0 7071 22 211 3,677 20 0

 400 18895 67 0 6074 8 152 2,828 6 268

 500 18270 49 199 4792 14 164 2,617 11 232

 600 14243 53 104 3008 6 90 1,662 3 210

 700 9035 31 157 1856 11 66 1,707 5 171

 800 10777 66 237 2102 15 60 1,402 2 173

 900 6828 48 63 1640 8 33 1,326 5 95

 1000 9010 102 217 1901 14 76 1,363 2 161

 1100 5176 58 65 1207 10 30 1,088 10 82

 1200 6532 62 133 1097 4 47 954 7 123

 1300 3145 30 44 703 4 28 754 0 49

 1400 2852 26 47 533 2 17 455 0 46

 1500 4807 30 145 943 8 44 1,057 4 112

 1750 3719 43 59 618 9 20 584 0 41

 2000 4755 49 135 1087 10 45 1,069 2 71

 2500 4188 13 80 1030 6 33 1,077 0 31

 3000 3745 9 80 832 6 35 957 1 12

 3500 3033 28 56 639 3 32 820 1 16

 4000 2432 12 37 513 2 10 643 0 16

 4500 1776 9 23 320 0 8 433 0 8

 5000 1313 8 20 214 0 1 239 0 1

 5500 695 3 11 78 0 0 80 0 0

33
Table 10. Number of phosphate range outliers as a function of depth in the Indian Ocean. (N= number of observations, High= outliers exceeding high range values, Low= outliers below the

low range values)

 North Indian Equatorial Indian South Indian

 Depth N High Low N High Low N High Low

 0 504 7 0 1957 84 0 4 183 150 0

 10 247 0 0 1127 31 0 2,347 109 0

 20 418 5 0 1372 41 0 3,407 122 1

 30 285 5 0 1208 35 0 2,337 108 1

 50 498 10 0 1871 49 0 3,869 145 1

 75 458 4 0 2067 16 0 3,208 120 0

 100 472 1 0 2110 3 0 3,276 116 0

 125 191 0 0 1283 3 0 1,276 5 0

 150 463 1 0 1944 3 0 2,824 13 0

 200 455 5 4 1924 6 49 2,996 23 0

 250 205 0 2 1256 4 19 1,487 7 0

 300 433 1 0 1674 11 28 2,657 2 0

 400 438 2 2 1667 5 14 2,132 4 0

 500 411 5 1 1553 15 11 2,115 5 0

 600 282 1 0 1109 4 11 1,363 0 0

 700 181 2 0 726 4 12 1,228 2 59

 800 276 0 1 953 2 8 1,237 2 80

 900 148 2 0 476 2 8 1,031 3 58

 1000 306 6 1 998 7 6 1,196 7 63

 1100 91 5 0 439 4 6 850 2 48

 1200 146 3 0 585 1 6 726 3 35

 1300 67 2 0 345 2 4 797 2 39

 1400 85 1 0 272 1 4 566 9 28

 1500 184 8 0 553 7 6 1,006 5 23

 1750 164 6 0 458 2 2 603 2 13

 2000 217 1 0 719 3 5 1,145 3 34

 2500 176 3 1 688 1 7 994 2 26

 3000 148 1 1 537 9 6 820 2 27

 3500 73 0 0 373 4 3 609 1 15

 4000 46 9 0 368 7 4 541 1 6

 4500 4 0 0 209 8 3 356 0 4

 5000 1 0 0 65 1 3 174 0 7

 5500 0 0 0 10 0 1 40 0 0

34
Table 11. Number of phosphate range outliers as a function of depth in the Southern and Arctic Oceans(N= number of observations, High= outliers

exceeding high range values, Low= outliers below the low range values)

 Southern Ocean Arctic Ocean

 N High Low N High Low

 0 4035 9 16 10904 225 0

 10 3024 10 14 8383 117 0

 20 3023 12 11 9803 93 0

 30 3387 4 5 5497 28 0

 50 4721 14 14 9528 15 0

 75 3389 14 12 5546 7 0

 100 3407 0 12 8054 8 0

 125 956 1 5 2109 4 0

 150 3145 0 10 4299 8 0

 200 3302 6 15 5924 11 0

 250 1374 1 12 2740 5 0

 300 2945 8 26 4486 5 0

 400 2961 9 18 3021 0 0

 500 1961 7 19 3016 3 0

 600 2071 7 8 1807 0 0

 700 1162 1 17 798 1 24

 800 1815 5 10 2154 0 68

 900 810 3 4 569 0 45

 1000 1778 2 12 2003 0 61

 1100 683 2 4 360 0 39

 1200 839 2 7 662 0 47

 1300 511 2 3 274 0 29

 1400 633 1 10 279 0 27

 1500 1549 3 11 686 0 46

 1750 1112 0 9 466 0 13

 2000 2139 4 11 744 0 34

 2500 2335 2 12 579 0 16

 3000 1997 2 6 399 0 28

 3500 1464 6 2 142 0 15

 4000 879 1 1 9 0 7

 4500 487 0 0 8 0 7

 5000 248 0 0 7 0 5

 5500 31 0 0 1 0 0

35
Table 12. Nitrate ranges for the Atlantic Ocean as a function of depth.

Depth North Atlantic Eq. Atlantic South Atlantic

Low High Low High Low High

0 0.01 18.00 0.01 6.00 0.01 22.00

10 0.01 18.00 0.01 10.00 0.01 26.00

20 0.01 18.00 0.01 14.00 0.01 26.00

30 0.01 18.00 0.01 18.00 0.01 30.00

50 0.01 26.00 0.01 22.00 0.01 30.00

75 0.01 30.00 0.01 30.00 0.01 34.00

100 0.01 30.00 0.01 30.00 0.01 34.00

125 0.01 30.00 0.01 30.00 0.01 34.00

150 0.01 30.00 0.01 30.00 0.01 34.00

200 0.01 30.00 0.01 34.00 0.01 38.00

250 0.01 34.00 0.01 38.00 0.01 38.00

300 0.01 38.00 0.01 42.00 0.01 38.00

400 0.01 42.00 0.01 42.00 2.00 42.00

500 0.01 42.00 0.01 46.00 2.00 46.00

600 0.01 42.00 0.01 46.00 2.00 46.00

700 6.00 46.00 0.01 46.00 2.00 46.00

800 6.00 46.00 0.01 46.00 2.00 46.00

900 6.00 46.00 0.01 46.00 2.00 46.00

1000 6.00 46.00 0.01 46.00 2.00 46.00

1100 6.00 46.00 0.01 46.00 2.00 46.00

1200 6.00 48.00 0.01 42.00 6.00 42.00

1300 6.00 48.00 0.01 42.00 6.00 42.00

1400 6.00 48.00 2.00 42.00 6.00 42.00

1500 6.00 48.00 2.00 42.00 6.00 42.00

1750 6.00 48.00 10.00 42.00 6.00 42.00

2000 6.00 48.00 10.00 42.00 6.00 42.00

2500 6.00 48.00 10.00 42.00 6.00 42.00

3000 6.00 48.00 10.00 38.00 6.00 42.00

3500 10.00 48.00 10.00 38.00 6.00 42.00

4000 10.00 48.00 10.00 38.00 6.00 42.00

4500 10.00 46.00 10.00 38.00 6.00 42.00

5000 10.00 44.00 10.00 38.00 10.00 42.00

5500 14.00 42.00 10.00 38.00 14.00 34.00

36
Table 13. Nitrate ranges for the Pacific Ocean as a function of depth.

Depth North Pacific Eq. Pacific South Pacific

Low High Low High Low High

0 0.01 26.00 0.01 22.00 0.01 18.00

10 0.01 26.00 0.01 22.00 0.01 18.00

20 0.01 26.00 0.01 22.00 0.01 18.00

30 0.01 30.00 0.01 26.00 0.01 22.00

50 0.01 30.00 0.01 34.00 0.01 26.00

75 0.01 34.00 0.01 34.00 0.01 30.00

100 0.01 34.00 0.01 34.00 0.01 30.00

125 0.01 42.00 0.01 34.00 0.01 30.00

150 0.01 42.00 0.01 38.00 0.01 30.00

200 0.01 46.00 0.01 38.00 0.01 38.00

250 0.01 46.00 0.01 42.00 0.01 38.00

300 0.01 46.00 0.01 42.00 0.01 38.00

400 0.01 46.00 0.01 42.00 4.00 42.00

500 0.01 46.00 0.01 46.00 6.00 46.00

600 0.01 50.00 0.01 46.00 6.00 50.00

700 2.00 50.00 0.01 50.00 6.00 50.00

800 2.00 54.00 0.01 56.00 10.00 50.00

900 2.00 54.00 0.01 56.00 10.00 50.00

1000 2.00 54.00 0.01 56.00 10.00 50.00

1100 2.00 54.00 0.01 56.00 10.00 50.00

1200 2.00 54.00 0.01 56.00 10.00 54.00

1300 2.00 54.00 0.01 50.00 10.00 54.00

1400 2.00 54.00 2.00 50.00 10.00 54.00

1500 2.00 54.00 2.00 50.00 10.00 54.00

1750 2.00 54.00 2.00 50.00 10.00 54.00

2000 2.00 54.00 2.00 50.00 10.00 54.00

2500 2.00 54.00 2.00 50.00 10.00 54.00

3000 2.00 50.00 2.00 46.00 10.00 54.00

3500 2.00 46.00 2.00 46.00 10.00 54.00

4000 2.00 46.00 2.00 46.00 10.00 54.00

4500 2.00 42.00 2.00 46.00 10.00 42.00

5000 10.00 42.00 2.00 46.00 10.00 38.00

5500 14.00 42.00 2.00 46.00 14.00 38.00

37
Table 14. Nitrate ranges for the Indian Ocean as a function of depth.

Depth North Indian Eq. Indian South Indian

Low High Low High Low High

0 0.01 14.00 0.01 4.00 0.01 18.00

10 0.01 18.00 0.01 6.00 0.01 18.00

20 0.01 18.00 0.01 6.00 0.01 18.00

30 0.01 18.00 0.01 14.00 0.01 18.00

50 0.01 30.00 0.01 18.00 0.01 18.00

75 0.01 30.00 0.01 26.00 0.01 22.00

100 0.01 30.00 0.01 30.00 0.01 22.00

125 0.01 42.00 0.01 34.00 0.01 26.00

150 0.01 42.00 0.01 34.00 0.01 30.00

200 0.01 42.00 0.01 38.00 0.01 30.00

250 2.00 42.00 0.01 38.00 0.01 30.00

300 2.00 50.00 0.01 46.00 0.01 30.00

400 2.00 50.00 0.01 46.00 0.01 34.00

500 2.00 50.00 0.01 46.00 0.01 34.00

600 2.00 50.00 0.01 46.00 0.01 38.00

700 2.00 54.00 0.01 54.00 0.01 46.00

800 2.00 54.00 0.01 54.00 0.01 46.00

900 2.00 54.00 0.01 54.00 0.01 46.00

1000 2.00 54.00 0.01 54.00 0.01 46.00

1100 2.00 54.00 0.01 54.00 0.01 46.00

1200 2.00 54.00 0.01 54.00 0.01 46.00

1300 2.00 54.00 0.01 54.00 0.01 46.00

1400 2.00 54.00 0.01 54.00 0.01 46.00

1500 2.00 54.00 2.00 54.00 2.00 46.00

1750 2.00 54.00 2.00 54.00 2.00 46.00

2000 2.00 54.00 2.00 54.00 2.00 46.00

2500 4.00 54.00 2.00 54.00 2.00 46.00

3000 4.00 54.00 2.00 46.00 2.00 46.00

3500 4.00 54.00 2.00 46.00 2.00 46.00

4000 4.00 46.00 2.00 46.00 2.00 46.00

4500 4.00 46.00 2.00 46.00 2.00 46.00

5000 4.00 46.00 2.00 46.00 2.00 46.00

5500 10.00 46.00 2.00 46.00 10.00 46.00

38
Table 15. Nitrate ranges for the Southern and Arctic Oceans as a function of depth.

Depth Southern Ocean Arctic Ocean

Low High Low High

0 0.01 46.00 0.01 18.00

10 0.01 46.00 0.01 18.00

20 0.01 46.00 0.01 18.00

30 0.01 46.00 0.01 18.00

50 0.01 46.00 0.01 18.00

75 0.01 46.00 0.01 18.00

100 0.01 46.00 0.01 22.00

125 0.01 46.00 0.01 22.00

150 0.01 46.00 0.01 22.00

200 0.01 46.00 0.01 26.00

250 0.01 46.00 0.01 26.00

300 0.01 46.00 0.01 26.00

400 4.00 46.00 0.01 28.00

500 6.00 46.00 0.01 28.00

600 6.00 46.00 0.01 32.00

700 6.00 46.00 0.01 32.00

800 14.00 46.00 0.01 42.00

900 14.00 46.00 0.01 42.00

1000 14.00 50.00 0.01 46.00

1100 14.00 50.00 0.01 46.00

1200 14.00 50.00 0.01 46.00

1300 14.00 50.00 0.01 50.00

1400 14.00 50.00 0.01 50.00

1500 14.00 50.00 0.01 50.00

1750 14.00 50.00 0.01 50.00

2000 14.00 50.00 0.01 54.00

2500 14.00 50.00 0.01 54.00

3000 14.00 50.00 0.01 54.00

3500 14.00 46.00 2.00 54.00

4000 14.00 46.00 2.00 46.00

4500 14.00 42.00 2.00 46.00

5000 14.00 42.00 2.00 46.00

5500 18.00 42.00 2.00 46.00

39
Table 16.Number of nitrate range outliers as a function of depth in the Atlantic Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Atlantic Equatorial Atlantic South Atlantic

 Depth N High Low N High Low N High Low

 0 3979 270 619 1771 84 448 1924 27 82

 10 2793 255 430 1069 75 214 1261 11 40

 20 2920 246 328 1269 70 242 1457 15 43

 30 2269 272 291 1541 66 195 1373 6 52

 50 3715 129 386 1887 52 208 1810 11 59

 75 2740 55 246 1782 10 171 1502 6 40

 100 3519 48 208 1575 10 90 1675 8 24

 125 1044 13 67 891 2 27 626 1 17

 150 2522 41 94 1443 9 17 1522 6 7

 200 2965 47 78 1402 9 30 1857 5

 250 1295 10 58 1043 0 14 1219 2 0

 300 2684 9 74 1212 0 12 1552 10 2

 400 2440 10 58 1344 9 2 1983 2 21

 500 2174 11 48 1109 3 2 1718 2 17

 600 1835 5 42 851 1 0 1564 4 12

 700 1368 8 50 635 6 0 1336 1 12

 800 1668 1 90 641 2 0 1250 3 15

 900 1167 3 37 420 6 0 939 2 6

 1000 1641 8 86 496 5 1 952 4 18

 1100 614 4 37 343 0 1 761 1 3

 1200 1186 1 57 345 1 0 698 9 25

 1300 584 2 36 244 1 0 604 1 9

 1400 828 0 26 218 0 1 581 4 9

 1500 1467 0 80 404 0 1 820 5 41

 1750 1273 1 30 259 0 3 806 2 4

 2000 1632 0 26 329 0 3 961 2 6

 2500 1576 0 25 293 0 1 1122 2 9

 3000 1117 0 16 276 0 3 1049 3 7

 3500 852 0 20 240 0 1 943 3 5

 4000 711 0 11 243 0 0 786 5 6

 4500 591 0 10 189 0 0 579 1 8

 5000 412 0 11 119 0 0 394 0 6

 5500 129 0 3 43 0 0 148 10 0

40
Table 17. Number of nitrate range outliers as a function of depth in the Pacific Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Pacific Equatorial Pacific South Pacific

 Depth N High Low N High Low N High Low

 0 8243 150 2226 3246 22 787 1096 3 326

 10 6473 127 1904 2199 20 577 414 4 104

 20 5620 153 1552 2167 33 458 568 2 151

 30 6556 104 1533 1834 33 341 385 3 78

 50 9342 116 1880 3363 22 519 1086 1 289

 75 8990 80 1224 3434 29 295 1037 4 239

 100 8733 103 716 3831 16 127 1113 3 226

 125 6152 11 257 3324 20 37 690 5 100

 150 9358 36 171 5235 10 16 1216 7 129

 200 9804 28 57 5380 19 5 1350 1 37

 250 6111 15 26 4388 5 4 1002 1 2

 300 8033 26 48 4439 10 3 1378 7 2

 4oo 7175 33 24 3463 25 5 1151 4 8

 500 6838 48 34 2677 12 4 941 3 2

 600 5006 9 20 1635 21 4 732 1 2

 700 3018 10 60 1076 4 5 741 2 1

 800 3515 10 65 1139 4 3 591 6 4

 900 2490 5 32 931 2 2 595 4 2

1000 3001 11 46 1050 3 1 620 4 0

1100 1699 5 21 625 0 1 453 1 1

1200 2023 11 33 582 0 2 388 1 0

1300 1166 1 25 395 2 2 345 0 0

1400 1140 6 18 291 0 3 215 1 1

1500 1865 6 27 540 0 5 418 0 0

1750 1643 5 12 367 1 1 391 0 0

2000 2430 9 16 655 0 2 599 0 0

2500 2291 3 10 675 1 0 700 0 0

3000 2178 7 10 569 3 0 703 0 0

3500 1911 2 7 433 1 0 645 0 0

4000 1610 4 2 375 0 0 506 0 0

4500 1397 4 1 251 0 0 339 2 0

5000 1057 5 30 171 0 0 201 2 0

5500 591 0 12 59 1 0 74 1 0

41
Table 18. Number of nitrate range outliers as a function of depth in the Indian Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Indian Equatorial Indian South Indian

 Depth N High Low N High Low N High Low

 0 228 5 23 861 4 341 1187 5 441

 10 79 0 23 294 0 159 322 5 119

 20 217 2 27 702 1 341 1018 7 387

 30 103 1 21 413 0 157 391 5 153

 50 234 1 21 890 0 228 1257 6 392

 75 231 2 4 902 0 67 1064 3 250

 100 258 2 0 998 3 6 1307 8 136

 125 136 0 0 607 5 0 691 1 20

 150 254 0 0 877 5 0 1250 0 28

 200 258 3 0 908 3 0 1372 3 11

 250 88 0 1 617 3 2 752 5 2

 300 270 0 0 863 1 1 1348 6 1

 400 274 2 0 787 4 0 1068 4 3

 500 208 0 1 720 3 1 1130 9 4

 600 192 1 0 531 4 0 696 8 0

 700 95 2 0 204 3 0 650 2 1

 800 182 1 0 417 0 0 536 3 1

 900 93 1 1 126 3 0 538 1 0

 1000 182 1 0 429 2 0 521 5 0

 1100 25 0 0 120 1 0 464 4 0

 1200 90 1 1 268 2 1 377 4 0

 1300 38 0 0 151 1 0 454 2 0

 1400 54 0 0 135 0 0 242 3 0

 1500 89 1 0 248 0 3 563 1 7

 1750 78 1 0 173 1 0 272 7 1

 2000 130 0 0 331 2 0 587 5 4

 2500 98 1 0 286 0 1 510 4 4

 3000 90 1 0 213 0 0 388 1 3

 3500 53 0 0 153 1 1 313 2 0

 4000 28 0 0 165 1 1 286 1 0

 4500 1 0 0 91 0 0 200 1 1

 5000 0 0 0 22 0 0 98 0 2

 5500 0 0 0 5 0 0 20 0 0

42
Table 19. Number of nitrate range outliers as a function of depth in the Southern and Arctic Oceans. (N= number of observations, High= outliers exceeding

high range values, Low= outliers below the low range values)

 Southern Ocean Arctic Ocean

 N High Low N High Low

 0 1490 0 8 4198 5 447

 10 945 0 9 3401 8 335

 20 933 1 2 3360 8 178

 30 901 2 3 2593 17 84

 50 1451 3 1 3057 7 30

 75 1196 5 1 1889 5 9

 100 1266 4 0 2285 1 3

 125 543 1 0 436 0 2

 150 1160 4 1 1383 2 3

 200 1273 6 1 1538 1 1

 250 692 3 0 857 0 0

 300 1161 7 1 1135 0 2

 400 1263 6 3 926 0 0

 500 907 6 1 775 0 0

 600 943 10 0 458 0 0

 700 595 0 2 392 0 1

 800 749 4 4 346 0 2

 900 521 2 5 243 0 0

 1000 744 3 17 285 0 0

 1100 426 1 4 161 0 0

 1200 529 2 3 238 0 0

 1300 373 1 1 126 0 0

 1400 412 0 2 136 0 0

 1500 691 2 5 264 0 0

 1750 849 1 6 245 0 0

 2000 1198 0 13 356 0 0

 2500 1466 1 2 303 0 0

 3000 1246 0 4 233 0 0

 3500 919 2 2 90 0 4

 4000 527 0 1 6 0 3

 4500 296 1 0 4 0 1

 5000 185 0 0 5 0 1

 5500 19 0 0 1 0 0

43
Table 20. Silicate ranges for the Atlantic Ocean as a function of depth.

Depth North Atlantic Eq. Atlantic South Atlantic

Low High Low High Low High

0 0.0 50.0 0.0 40.0 0.0 30.0

10 0.0 50.0 0.0 40.0 0.0 30.0

20 0.0 50.0 0.0 40.0 0.0 30.0

30 0.0 50.0 0.0 40.0 0.0 30.0

50 0.0 60.0 0.0 50.0 0.0 30.0

75 0.0 60.0 0.0 50.0 0.0 30.0

100 0.0 60.0 0.0 50.0 0.0 40.0

125 0.0 60.0 0.0 60.0 0.0 40.0

150 0.0 60.0 0.0 60.0 0.0 40.0

200 0.0 80.0 0.0 60.0 0.0 40.0

250 0.0 80.0 2.0 60.0 2.0 40.0

300 0.0 80.0 2.0 80.0 2.0 40.0

400 0.0 100.0 2.0 80.0 2.0 40.0

500 2.0 100.0 2.0 80.0 2.0 80.0

600 2.0 100.0 2.0 80.0 2.0 80.0

700 2.0 120.0 2.0 80.0 2.0 80.0

800 2.0 120.0 2.0 80.0 2.0 80.0

900 2.0 120.0 2.0 80.0 5.0 120.0

1000 2.0 120.0 2.0 80.0 5.0 120.0

1100 2.0 120.0 2.0 80.0 5.0 120.0

1200 2.0 120.0 2.0 80.0 5.0 120.0

1300 2.0 120.0 2.0 80.0 5.0 120.0

1400 2.0 120.0 2.0 80.0 5.0 120.0

1500 2.0 120.0 2.0 80.0 5.0 120.0

1750 2.0 120.0 2.0 80.0 5.0 120.0

2000 5.0 130.0 5.0 80.0 5.0 120.0

2500 10..0 150.0 5.0 80.0 5.0 120.0

3000 10..0 150.0 5.0 80.0 5.0 140.0

3500 15.0 150.0 5.0 100.0 5.0 140.0

4000 15.0 150.0 10..0 100.0 10.0 160.0

4500 15.0 150.0 15.0 120.0 10.0 160.0

5000 15.0 150.0 30.0 160.0 20.0 160.0

5500 15.0 150.0 30.0 160.0 20.0 160.0

44
Table 21. Silicate ranges for the Pacific Ocean as a function of depth.

Depth North Pacific Equatorial Pacific South Pacific

Low High Low High Low High

0 0.0 60.0 0.0 80.0 0.0 80.0

10 0.0 60.0 0.0 80.0 0.0 80.0

20 0.0 60.0 0.0 80.0 0.0 80.0

30 0.0 60.0 0.0 80.0 0.0 80.0

50 0.0 60.0 0.0 80.0 0.0 80.0

75 0.0 80.0 0.0 80.0 0.0 80.0

100 0.0 80.0 0.0 80.0 0.0 80.0

125 0.0 80.0 0.0 80.0 0.0 80.0

150 0.0 80.0 0.0 80.0 0.0 80.0

200 2.0 80.0 2.0 80.0 0.0 80.0

250 2.0 80.0 2.0 80.0 1.0 100.0

300 2.0 80.0 2.0 80.0 1.0 100.0

400 2.0 100.0 2.0 80.0 1.0 100.0

500 5.0 140.0 5.0 100.0 1.0 120.0

600 5.0 140.0 5.0 120.0 1.0 120.0

700 10.0 140.0 5.0 120.0 1.0 120.0

800 10.0 140.0 5.0 120.0 1.0 120.0

900 10.0 160.0 5.0 140.0 2.0 120.0

1000 15.0 180.0 5.0 140.0 2.0 120.0

1100 15.0 180.0 10.0 180.0 2.0 120.0

1200 15.0 180.0 10.0 180.0 2.0 120.0

1300 15.0 180.0 10.0 180.0 5.0 160.0

1400 15.0 180.0 15.0 180.0 5.0 160.0

1500 15.0 200.0 15.0 180.0 10.0 160.0

1750 20.0 200.0 15.0 180.0 10.0 160.0

2000 20.0 200.0 15.0 180.0 15.0 160.0

2500 20.0 200.0 15.0 180.0 15.0 180.0

3000 20.0 200.0 15.0 180.0 15.0 180.0

3500 20.0 200.0 15.0 180.0 15.0 180.0

4000 20.0 200.0 15.0 180.0 15.0 180.0

4500 30.0 200.0 15.0 180.0 15.0 180.0

5000 30.0 200.0 20.0 180.0 15.0 180.0

5500 30.0 200.0 20.0 180.0 15.0 180.0

45
Table 22. Silicate ranges for the Indian Ocean as a function of depth.

Depth North Indian Equatorial Indian South Indian

Low High Low High Low High

0 0.0 30.0 0.0 50.0 0.0 80.0

10 0.0 30.0 0.0 50.0 0.0 80.0

20 0.0 30.0 0.0 50.0 0.0 80.0

30 0.0 30.0 0.0 50.0 0.0 80.0

50 0.0 30.0 0.0 50.0 0.0 80.0

75 0.0 30.0 0.0 50.0 0.0 80.0

100 0.0 60.0 0.0 50.0 0.0 80.0

125 0.0 60.0 0.0 50.0 0.0 80.0

150 0.0 60.0 2.0 60.0 0.0 80.0

200 5.0 80.0 2.0 60.0 0.0 80.0

250 10.0 80.0 2.0 60.0 2.0 80.0

300 10.0 80.0 2.0 60.0 2.0 80.0

400 10.0 80.0 2.0 60.0 2.0 80.0

500 10.0 80.0 5.0 80.0 2.0 80.0

600 10.0 80.0 5.0 80.0 2.0 100.0

700 10.0 80.0 10.0 80.0 2.0 100.0

800 10.0 80.0 10.0 80.0 2.0 100.0

900 15.0 120.0 15.0 120.0 5.0 120.0

1000 15.0 120.0 15.0 120.0 5.0 120.0

1100 20.0 120.0 15.0 120.0 5.0 120.0

1200 20.0 120.0 15.0 120.0 5.0 120.0

1300 20.0 120.0 15.0 120.0 10.0 120.0

1400 25.0 160.0 20.0 140.0 10.0 120.0

1500 25.0 160.0 20.0 140.0 15.0 140.0

1750 30.0 160.0 20.0 140.0 15.0 140.0

2000 30.0 160.0 30.0 160.0 20.0 160.0

2500 30.0 160.0 30.0 160.0 20.0 160.0

3000 30.0 180.0 30.0 160.0 20.0 160.0

3500 30.0 180.0 30.0 160.0 20.0 160.0

4000 30.0 180.0 30.0 160.0 20.0 160.0

4500 30.0 180.0 30.0 160.0 20.0 160.0

5000 30.0 180.0 30.0 160.0 20.0 160.0

5500 30.0 180.0 30.0 160.0 20.0 160.0

46
Table 23. Silicate ranges for the Southern and Arctic Oceans as a function of depth.

Depth Southern Ocean Arctic Ocean

Low High Low High

0 0.0 120.0 0.0 100.0

10 0.0 120.0 0.0 100.0

20 0.0 120.0 0.0 100.0

30 0.0 120.0 0.0 100.0

50 0.0 120.0 0.0 100.0

75 0.0 120.0 0.0 100.0

100 0.0 120.0 0.0 100.0

125 0.0 120.0 0.0 100.0

150 5.0 140.0 0.0 100.0

200 5.0 140.0 0.0 100.0

250 5.0 140.0 0.0 100.0

300 5.0 140.0 2.0 120.0

400 5.0 140.0 2.0 120.0

500 5.0 160.0 2.0 120.0

600 10.0 160.0 2.0 120.0

700 10.0 160.0 2.0 120.0

800 15.0 160.0 5.0 80.0

900 25.0 160.0 5.0 80.0

1000 25.0 160.0 5.0 80.0

1100 25.0 160.0 5.0 80.0

1200 25.0 160.0 5.0 80.0

1300 25.0 160.0 5.0 80.0

1400 25.0 160.0 5.0 80.0

1500 30.0 160.0 5.0 80.0

1750 30.0 160.0 5.0 80.0

2000 30.0 160.0 5.0 80.0

2500 35.0 160.0 5.0 80.0

3000 35.0 160.0 5.0 80.0

3500 35.0 160.0 5.0 80.0

4000 35.0 160.0 5.0 80.0

4500 35.0 160.0 5.0 80.0

5000 35.0 160.0 5.0 80.0

5500 35.0 160.0 5.0 80.0

47
Table 24. Number of silicate range outliers as a function of depth in the Atlantic Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Atlantic Equatorial Atlantic South Atlantic

 Depth N High Low N High Low N High Low

 0 7347 99 0 2509 11 0 2288 57 0

 10 4956 36 0 1904 6 0 1436 40 0

 20 4676 22 0 1851 5 0 1650 13 0

 30 4798 37 0 2300 8 0 1536 42 0

 50 7300 83 0 2691 4 0 2121 62 0

 75 5112 35 0 2584 5 0 1773 12 0

 100 7026 132 0 2469 7 0 1913 40 0

 125 2124 27 0 1308 2 0 732 7 0

 150 5017 140 0 2139 1 0 1824 34 0

 200 6354 111 0 2370 4 0 2177 56 0

 250 3222 67 0 1526 7 16 1393 25 78

 300 5885 141 0 2128 2 10 1959 92 52

 400 5275 117 0 2202 2 11 2386 125 36

 500 5221 135 405 2032 6 7 2014 30 16

 600 4110 169 214 1378 1 6 1845 41 15

 700 2821 102 61 879 1 1 1483 41 4

 800 3806 122 129 1081 11 4 1536 61 12

 900 2591 129 32 668 4 1 1065 26 6

 1000 3505 114 104 983 7 6 1211 66 10

 1100 1785 73 19 549 3 4 835 18 1

 1200 2372 78 45 615 2 1 830 43 10

 1300 1370 47 12 359 2 1 654 19 1

 1400 1508 42 13 336 0 1 710 16 2

 1500 2951 86 46 698 1 3 1020 54 7

 1750 2539 95 16 430 1 4 933 13 1

 2000 3291 150 59 589 0 2 1261 20 5

 2500 2967 131 149 469 1 3 1449 31 4

 3000 2289 150 97 452 3 0 1346 13 3

 3500 1734 132 101 404 0 0 1181 20 1

 4000 1536 124 34 396 1 0 997 11 1

 4500 1344 117 15 290 2 0 727 13 1

 5000 974 69 10 153 0 5 462 6 0

 5500 286 1 3 49 1 0 163 0 0

48
Table 25. Number of silicate range outliers as a function of depth in the Pacific Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Pacific Equatorial Pacific South Pacific

 Depth N High Low N high Low N High Low

 0 14525 117 0 3869 70 0 4188 229 0

 10 11090 104 0 2452 59 0 2545 195 0

 20 9444 116 0 2672 63 0 2931 190 0

 30 11277 111 0 2278 79 0 2703 188 0

 50 15613 150 0 3747 79 0 3349 178 1

 75 13111 58 0 3618 105 0 2889 156 0

 100 13866 79 0 3909 112 0 3013 135 1

 125 8438 43 0 2852 74 0 1664 55 0

 150 12862 193 0 4559 149 0 2852 117 0

 200 13986 402 550 4215 149 198 3351 107 0

 250 8382 264 180 3267 133 31 2317 52 125

 300 11453 622 170 3621 153 44 3076 76 198

 400 10634 398 69 2787 55 30 2254 47 112

 500 10644 105 129 2406 53 90 1818 12 99

 600 7546 107 53 1615 21 31 1428 9 64

 700 5060 137 38 1021 4 15 1231 10 72

 800 5584 365 50 1146 39 26 1216 5 38

 900 3591 71 22 862 8 9 852 7 64

 1000 4770 95 94 1137 30 19 1186 11 88

 1100 2765 51 37 519 10 9 593 4 45

 1200 3403 95 57 567 19 19 727 1 54

 1300 1631 49 17 267 1 12 305 0 48

 1400 1889 53 16 270 0 9 297 0 44

 1500 3449 72 22 579 12 11 547 0 84

 1750 2738 47 25 369 3 6 480 0 46

 2000 3666 75 65 693 19 12 719 2 83

 2500 3202 70 24 662 15 20 778 0 55

 3000 2950 27 29 549 2 20 785 0 44

 3500 2425 19 25 411 0 13 715 0 37

 4000 2090 16 39 339 2 5 537 0 15

 4500 1555 9 1 222 1 3 359 0 9

 5000 1252 1 1 166 0 0 210 0 3

 5500 688 2 0 54 0 0 74 0 1

49
Table 26. Number of silicate range outliers as a function of depth in the Indian Ocean. (N= number of observations, High= outliers exceeding high range

values, Low= outliers below the low range values)

 North Indian Equatorial Indian South Indian

 Depth N High Low N High Low N High Low

 0 393 3 0 1334 6 0 2213 78 0

 10 103 0 0 690 0 0 1547 57 0

 20 290 0 0 897 7 0 1696 53 0

 30 98 0 0 712 7 0 1456 52 0

 50 379 2 0 1166 4 0 2049 53 0

 75 294 5 0 997 1 0 1582 44 0

 100 362 3 0 1110 25 0 1730 45 0

 125 145 1 0 562 4 0 629 15 0

 150 309 6 0 1013 26 5 1539 35 0

 200 352 5 1 1131 33 7 1606 33 0

 250 105 7 0 679 27 3 773 16 55

 300 258 5 0 849 5 4 1333 31 99

 400 308 4 0 941 10 1 1294 38 51

 500 297 9 0 982 24 4 1097 33 31

 600 238 3 0 595 2 1 876 17 21

 700 145 8 0 379 10 5 513 15 13

 800 244 14 0 696 47 2 844 23 10

 900 122 4 0 306 5 6 450 13 27

 1000 261 3 0 731 25 3 820 29 26

 1100 74 3 0 264 13 5 334 13 16

 1200 127 4 0 390 27 3 472 24 15

 1300 56 1 0 271 12 4 299 13 11

 1400 64 0 0 224 5 4 325 15 9

 1500 157 5 0 472 24 3 606 33 19

 1750 123 1 0 387 19 0 476 14 6

 2000 165 4 0 559 6 6 849 13 16

 2500 123 3 0 499 1 5 674 13 4

 3000 113 1 0 413 3 0 541 15 4

 3500 52 1 0 272 3 0 368 10 2

 4000 36 0 0 263 3 0 318 10 2

 4500 2 0 0 149 0 0 205 5 0

 5000 1 0 0 39 0 0 100 4 1

 5500 0 0 0 3 0 0 25 0 0

50
Table 27. Number of silicate range outliers as a function of depth in the Southern and Arctic Oceans. (N= number of observations, High= outliers exceeding

high range values, Low= outliers below the low range values)

 Southern Ocean Arctic Ocean

 Depth N High Low N High Low

 0 3301 14 0 6919 279 0

 10 2400 12 0 4887 418 0

 20 2390 11 0 5758 220 0

 30 2385 2 0 3577 170 0

 50 3738 16 0 5504 82 0

 75 2842 20 0 2627 57 0

 100 2924 17 0 4692 51 0

 125 925 6 0 618 7 0

 150 2701 11 89 2285 36 0

 200 2918 16 73 3801 32 0

 250 1393 11 29 1642 13 0

 300 2639 21 32 3003 24 76

 400 2660 18 19 2048 28 41

 500 1840 14 13 2520 24 41

 600 1877 1 22 1342 22 36

 700 1048 5 7 568 15 18

 800 1676 9 11 1633 19 172

 900 826 4 22 386 11 29

 1000 1616 16 20 1577 15 132

 1100 696 3 8 223 4 14

 1200 889 8 12 387 8 20

 1300 560 1 5 160 1 8

 1400 667 6 0 185 0 14

 1500 1434 10 13 482 2 15

 1750 1188 9 13 328 2 7

 2000 2108 17 10 520 2 10

 2500 2367 18 18 408 0 10

 3000 2022 17 19 326 0 6

 3500 1514 9 10 126 2 5

 4000 936 8 7 6 0 3

 4500 521 8 0 4 0 2

 5000 264 5 0 3 0 0

 5500 31 0 0 2 0 0

51
Table 28. Acceptable distances for "inside" and "outside" values used in the ReinigerRoss scheme for interpolating observed level data to standard levels

Standard Levels Standard Depths Acceptable

distances for

inside values

Acceptable

distances for

outside values

1 0 5 200

2 10 50 200

3 20 50 200

4 30 50 200

5 50 50 200

6 75 50 200

7 100 50 200

8 125 50 200

9 150 50 200

10 200 50 200

11 250 100 200

12 300 100 200

13 400 100 200

14 500 100 400

15 600 100 400

16 700 100 400

17 800 100 400

18 900 200 400

19 1000 200 400

20 1100 200 400

21 1200 200 400

22 1300 200 1000

23 1400 200 1000

24 1500 200 1000

25 1750 200 1000

26 2000 1000 1000

27 2500 1000 1000

28 3000 1000 1000

29 3500 1000 1000

30 4000 1000 1000

31 4500 1000 1000

32 5000 1000 1000

33 5500 1000 1000

52
Table 29. Number of observations interpolated from observed levels to standard levels using the

different interpolation schemes (numbers in parenthesis are percent of standard levels

filled using each method).

SD file Phosphate Nitrate Silicate

Direct substitution 609013 (38.9%) 207865 (34.6%) 313825 (35.3%)

Reineger Ross 639378 (40.8%) 267368 (44.5%) 370043 (41.7%)

Two above one below

interpolation 99687 (6.4%) 38059 (6.3%) 61934 (7.0%)

One above two below

interpolation 55670 (3.5%) 26066 (4.3%) 38708 (4.3%)

Linear Interpolation 162765 (10.4%) 61227 (10.2%) 103651 (11.7%)

Total standard levels 1566513 600585 888161

SD2 file Phosphate Nitrate Silicate

Direct substitution 120398 (63.9%) 38867 (61.5%) 78008 (55.2%)

Reineger Ross 48693 (25.8%) 12439 (19.7%) 29410 (20.8%)

Two above one below

interpolation

6525 (3.5%) 4034 (6.4%) 10433 (7.4%)

One above two below

interpolation

5016 (2.7%) 2774 (4.4%) 9699 (6.8%)

Linear Interpolation 7697 (4.1%) 5045 (8.0%) 13891 (9.8%)

Total standard levels 188329 63159 141441

53
Table 30. Cruises flagged due to nitrate errors in the SD file (F.S.U. refers to the Former

Soviet Union)

NODC Cruise Country Date Location Profiles

88 South Africa March 1977 South Pacific 21

1182 U.S. Jan-Mar 1966 North Pacific 80

7064 F.S.U. May-Jun 1982 Equatorial Indian 37

7065 F.S.U. Jun-Jul 1982 Equatorial Indian 73

8638 U.S. Nov-Dec 1983 South Atlantic 84

Table 31. Cruises flagged due to silicate errors in the SD file (F.S.U. refers to the Former

Soviet Union)

NODC Cruise Country Date Location Profiles

44 F.S.U. Jul-Aug 1960 North Pacific 233

251 U.S. Feb-Mar 1964 North Atlantic 171

380 F.S.U. Jun-Sep 1972 North Atlantic 362

392 Canada Aug-Oct 1965 North Atlantic 147

8638 U.S. Nov-Dec 1983 South Atlantic 84

54
Table 32. Number of profiles containing flagged observations for each step of the quality control of phosphate data.

 QC PROCEDURE WINTER SPRING SUMMER FALL TOTAL

 SD SD2 SD SD2 SD SD2 SD SD2 SD SD2

RANGE CHECK 2332 550 2309 417 2874 502 1739 444 9254 1913

STATISTICAL CHECK 1130 191 1348 145 1750 134 935 131 5163 601

OBJECTIVE ANALYSIS 77 144 121 57 114 142 81 33 393 376

Table 33. Number of profiles containing flagged observations for each step of the quality control of nitrate data.

 QC PROCEDURE WINTER SPRING SUMMER FALL TOTAL

 SD SD2 SD SD2 SD SD2 SD SD2 SD SD2

RANGE CHECK 2118 137 2883 153 2853 121 1498 124 9352 535

STATISTICAL CHECK 565 16 545 19 573 19 354 19 2037 68

OBJECTIVE ANALYSIS 49 16 26 2 34 0 46 8 155 26

Table 34. Number of profiles containing flagged observations for each step of the quality control of silicate data.

 QC PROCEDURE WINTER SPRING SUMMER FALL TOTAL

 SD SD2 SD SD2 SD SD2 SD SD2 SD SD2

RANGE CHECK 2826 398 3013 317 3608 410 2017 317 11464 1502

STATISTICAL CHECK 670 1 772 0 1056 0 463 3 3193 272

OBJECTIVE ANALYSIS 451 0 76 0 114 0 161 0 451 0

55
Table 35. Number of profiles (N) containing observations flagged during the range check, and the

percentage of low and high outliers (% Low and % High) for each basin.

Basins Phosphate Nitrate Silicate

Total N % low % high Total N % low % high Total N % low % high

N. Atlantic 5688 0.7 1.7 5127 6.4 2.5 4677 1.3 2.6

Eq.Atlantic 1367 0.3 1.8 2108 6.5 1.6 197 0.2 0.3

S. Atlantic 591 0.5 0.6 780 1.6 0.5 1413 0.6 2.6

N. Pacific 4288 0.5 0.6 13242 8.2 0.8 5836 0.8 1.8

Eq. Pacific 2165 1.4 0.7 3527 5.3 0.5 2151 1.1 2.6

S. Pacific 4161 3.0 3.5 1777 7.5 0.3 3217 2.7 3.4

N. Indian 109 0.2 1.2 152 2.8 0.7 106 0.0 1.8

Eq. Indian 606 0.7 1.1 1361 9.0 0.4 455 0.4 1.9

S. Indian 1543 1.1 1.8 2092 9.0 0.6 1300 1.5 2.9

Antarctic 454 0.5 0.2 180 0.4 0.3 796 0.8 0.6

Arctic 1041 0.5 0.6 1160 3.5 0.2 2203 1.1 2.6

Total 22013 9.4 13.8 31506 60.2 8.4 22351 10.5 23.1

56
Fig 1 Seasonal distribution of (a) phosphate, (b) nitrate and (c) silicate profiles as a function of year

for each season

57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74

75