**National Climatic Data Center**

**DATA DOCUMENTATION**

**FOR**

**DATA SET 6150 (DSI-6150)**

# Climate Analysis Center (CAC) Sea Surface Temperature (SST) Analyses

# 

# December 6, 2002

National Climatic Data Center

151 Patton Ave.

Asheville, NC 28801-5001 USA

**Table of Contents**

[Topic Page Number]{.underline}

1\.
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3

2\. Element Names and Definitions**:**
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3\. Start
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4\. Stop
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5\.
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6\. How to order
data\...\...\...\...\...\...\...\...\...\...\...\...\...\... 5

7\. Archiving Data Center.
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8\. Technical
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9\. Known Uncorrected
Problems\...\...\...\...\...\...\...\...\...\...\... 6

10\. Quality
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11\. Essential Companion Data
Sets\...\...\...\...\...\...\...\...\...\... 6

12\.
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6

**1. [Abstract]{.underline}:** The Climate Analysis Center\'s Sea
Surface Temperature Data Set, referred to as \"CAC SSTs\", contains in
situ SSTs, blended SSTs (in situ SSTs blended with AVHRR derived SSTs),
blended anomalies, COADS/Ice SST Climatology, and Land/Sea Mask. The
blended anomalies are produced by GSFC DAAC from the SST Climatology
data provided by the Climate Analysis Center (renamed CPC - Climate
Prediction Center). The in situ analyses cover 40 degrees south to 60
degrees north. All other gridded analyses are global. The values for
Land/Sea Mask are available on a 0.5 X 0.5 degree latitude/longitude
grid; all other gridded values are available on a 2 X 2 degree
latitude/longitude grid. The in situ analyses grids are available from
January, 1970, to December, 1981, inclusive. The blended analyses grids,
derived from in situ SSTs and AVHRR derived SSTs, are available from
January, 1982, to present. With the exception of the Land Mask, all
gridded values are monthly means. The SST field is the analyzed SST
which is obtained by solving Poison\'s equation forced by satellite
analyzed field with internal and external boundary values anchored by an
in situ analysis. The climatology used here was computed using the
two-degree resolution COADS data for the period (1950-1979). To improve
the coverage, SST\'s were inferred from monthly climatological ice
limits and obtained from monthly satellite SST fields. A summary of
these results have been included in Reynolds (1988). The monthly
climatological fields can be determined from these data by subtracting
the monthly anomaly field from the monthly mean. Climatological SST
values north of 80 degrees North and South of 80 degrees South should be
set to -1.8 degrees C (the freezing point temperature of sea water) for
all months. The CAC sea surface temperature (SST) data described in this
document are of two types: (1) Sea Surface Temperature [in]{.underline}
[SITU]{.underline} Analysis and (2) Sea Surface Temperature Blended
Analysis. There are two file types.

In Sea Surface Temperature (SST) [in]{.underline} [SITU]{.underline}
Analysis are from [in]{.underline} [SITU]{.underline} (ship and buoy)
data only. These data are contained in files 1 and 2 discussed below.

The monthly optimum interpolation (OI) fields are derived by a linear
interpretation of the weekly OI fields to daily fields, then averaging
the daily fields over a month. The monthly fields are in the same format
and spatial resolution as the weekly fields.

The first file contains monthly mean analyzed SST fields -- the land
mask used for the blended SST analysis. The second file contains the
monthly-analyzed anomaly SST field (the monthly temperature has been
subtracted from the means of the first file). The climatology was based
on a combination of [in]{.underline} [situ]{.underline} and satellite
SST observations, and includes SST\'s inferred from climatological ice
limits. A complete description of the analysis procedures is given by
Reynolds (1988, [Journal]{.underline} [of]{.underline}
[Climate]{.underline}, [1]{.underline}, 75-86).

Both files consist of monthly fields from January 1970 through December
1984. Each field is divided into two regions called ATLANTIC and
PACIFIC. The two regions overlap and have been interpolated over land.

The SST climatology of Reynolds (1982, NOAA Technical Report NWS 31) was
originally used as climatology for these analyses. However, differences
between this climatology and other SST climatologies have been noted.
These differences were not primarily due to analysis methods but due to
the use of data from different periods of time. The Reynolds (1982)
climatology includes data from the 1850\'s through 1970\'s; the other
climatologies used no data prior to 1950.

The climatology used here was computed using the two-degree resolution
COADS data for the period (1950-1979). To improve the coverage, SST\'s
were inferred from monthly climatological ice limits and obtained from
monthly satellite SST fields. A summary of these results have been
included in Reynolds (1988, [Journal]{.underline} [of]{.underline}
[Climate,]{.underline} [1]{.underline}, 75-86.) The monthly
climatological fields can be determined from these data by subtracting
the monthly anomaly field from the monthly mean. Climatological SST
values north of 80^o^N and south of 80^o^S should be set to -1.8^o^C
(the freezing point temperature of sea water) for all months.

This data set is considered "inactive" as it has had no data added in 7
years.

**2. [Element Names and Definitions]{.underline}:**

Both files consist of monthly fields from January 1970 through December
1984. Each field is divided into two regions called ATLANTIC and
PACIFIC. The two regions overlap and have been interpolated over land.
If the SST array is dimensioned SST (101,51) the SST field can be read
by two reads.

READ (1,1) IMO,IYR,IX,IY

1 FORMAT (4I20)

READ (1,2) ((SST(I,J),I=1,101, J=1,51)

2 FORMAT (16F5.1)

IMO = month (1-12) IX=1 for ATLANTIC, 2 for PACIFIC

IYR = year (70-84) IY=1 for mean SST and 2 for anomaly SST

The first index, I, defines the longitude and J defines the latitude of
the location of the SST field.

For all fields: J-1 is centered at 40^o^S, J-2 is at 38^o^S and so on to
J=51 at 60^o^N. For the ATLANTIC fields I-1 is centered at 100^o^W, I-2
is at 98^o^W and so on to I-101 at 100^o^E. For the PACIFIC fields, I=1
is centered at 100^o^E, I-2 is at 102^o^E, and so on to I-101 at 60^o^W.

The Sea Surface Temperature (SST) Blended Analyses are contained in the
third and fourth files. The third file contains the monthly-analyzed SST
fields; the fourth file contains the monthly anomaly SST fields (the
monthly climatology has been subtracted from the fields in the third
file).

The monthly data is available from January 1982 to present on a
two-degree latitude and longitude grid. These fields are analyzed from a
blend of [in]{.underline} [situ]{.underline} and AVHRR (advanced very
high resolution radiometer) satellite data. A complete description of
the analysis procedures is given by Reynolds (1988,
[Journal]{.underline} [of]{.underline} [Climate]{.underline},
[1]{.underline}, 75-86).

The following statements can read files three and four if the arrays SST
and IFLAG are dimensioned (180,90):

READ (1,1) IDA,IMO,IYR,IY

1 FORMAT (4I20)

READ (1,2) (SST(I,J),I=1,180), J=1,91)

2 FORMAT (16F5.1)

READ (1,3) ((IFLAG (I,J), I=1,180), J=1,91)

3 FORMAT (80I1)

IDA= number of days of data analyzed

IMO= month (1-12)

IYR= year (82 to present)

IY= 1 for mean SST, 2 for anomaly SST

The SST field is the analyzed SST, which is obtained by solving
Poison\'s equation forced by a satellite-analyzed field with internal
and external boundary values anchored by an [in]{.underline}
[situ]{.underline} analysis. The IFLAG array gives information about
each analyzed array as follows:

IFLAG = 0: The blended value has been anchored by the satellite
analysis; there are [at]{.underline} [least]{.underline}
[10]{.underline} satellite observations per month.

IFLAG = 1: The blended value has been anchored by the [in]{.underline}
[situ]{.underline} analysis; there are [at]{.underline}
[least]{.underline} [5]{.underline} [in]{.underline} [situ]{.underline}
observations per month.

IFLAG = 2: The blended value has been anchored by the satellite
analysis; there are [less]{.underline} [than]{.underline}
[10]{.underline} satellite observations per month.

IFLAG = 3: Pole values; the SST mean has been set to -1.8^o^C; the SST
anomaly has been set to 0.

IFLAG = 5: The blended value has been determined by relaxation of the
[in]{.underline} [situ]{.underline} analysis with satellite forcing; the
number of satellite observations is [at]{.underline} [least]{.underline}
[10]{.underline} per month.

IFLAG = 6: The blended value has been determined by relaxation of the
[in]{.underline} [situ]{.underline} analysis with the satellite forcing
set to zero; the number of satellite observations is [less]{.underline}
[than]{.underline} [10]{.underline} per month.

IFLAG = 7: The blended value has been determined by extrapolation and is
unreliable. Data values north of 80^o^N and south of 80^o^S always
belong to this category.

The location of the SST and IFLAG arrays is defined by the first index,
I, for longitude and the second index J for latitude. For I=1 the grid
is centered at 0^o^, I=2 at 2^o^E and so on eastward to I=180 at 2^o^W
(358^o^E). For J=1 the grid is centered at 90^o^S, J=2 at 88^o^S and so
on northward to J=91 at 90^o^N.

[**http://www.cpc.ncep.noaa.gov/data/cddb/**](http://www.cpc.ncep.noaa.gov/data/cddb/)

**3. [Start Date]{.underline}:** 19500101

**4. [Stop Date]{.underline}:** 19951231

**5. [Coverage]{.underline}:** Atlantic and Pacific Oceans

**6. [How to Order Data]{.underline}:**

Ask NCDC's Climate Services about the cost of obtaining this data set.

Phone: 828-271-4800

FAX: 828-271-4876

E-mail: [**NCDC.Orders@noaa.gov**](mailto:NCDC.Orders@noaa.gov)

**7. [Archiving Data Center]{.underline}:**

National Climatic Data Center

Federal Building

151 Patton Avenue

Asheville, NC 28801-5001

Phone: (828) 271-4800**.**

**8. [Technical Contact]{.underline}:**

National Climatic Data Center

Federal Building

151 Patton Avenue

Asheville, NC 28801-5001

Phone: (828) 271-4800**.**

**9. [Known Uncorrected Problems]{.underline}:** None.

**10. [Quality Statement]{.underline}:** No specific information was
provided with original documentation. Verifications statistics are
provided in reference 2 below.

**11. [Essential Companion Datasets]{.underline}:** None.

**12. [References]{.underline}:**

Reynolds, R. W., and Roberts 1987: Tropical Ocean-Atmosphere Newsletter,
No. 37, 15-17, published by CIMAS, University of Miami, 4600
Rickenbacker Causeway, Miami, Fl 33149

Reynolds, R. W., 1988: A real-time global sea surface temperature
analysis. Journal of Climate, 1, 75-86.

Reynolds, R. W., and D. C. Marsico, 1993: An improved real-time global
sea surface temperature analysis. Journal of Climate, 6, 114-119.

Reynolds, R. W., and T.M. Smith, 1994: Improved global sea surface
temperature analyses using optimum interpolation. Journal of Climate, 7,
929-948.

Reynolds, R. W., and T.M. Smith, 1995: A high-resolution global sea
surface temperature climatology. Journal of Climate, 8, 1571-1583.

Slutz, R. J., S. J. Lubker, J. D. Hiscox, S. D. Woodruff, R. L. Jenne,
D. H. Joseph, P. M. Steuer, J. D. Elms, 1985: Comprehensive
Ocean-Atmosphere Data Set: Release 1. NOAA Environmental Research
Laboratory, Boulder, CO, 268 pp.

**[\"http://www.cdc.noaa.gov/cdc/data.reynolds_sst.html\"](http://www.cdc.noaa.gov/cdc/data.reynolds_sst.html)**

**[\"http://www.cdc.noaa.gov/cdc/reynolds_sst.info.html\"](http://www.cdc.noaa.gov/cdc/reynolds_sst.info.html)**

[**\"http://www.emc.ncep.noaa.gov/research/cmb/sst_analysis/\"**](http://www.emc.ncep.noaa.gov/research/cmb/sst_analysis/)