NOAA Polar Orbiter Data User's Guide

Section 5.4

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5.4 Radiation Budget Products

There are six types of digital Radiation Budget products that were archived by SSB for the NOAA Polar Orbiting Satellites through May 1999. For any data after May 1999, including some NOAA-14 data, please see Section 9.3.1 of the NOAA KLM User's Guide for the archive format. All radiation budget products are currently produced by the NOAA/NESDIS Office of Satellite Data Processing and Distribution's Product Systems Branch (OSDPD/PSB).

The first type is the Monthly Radiation Budget. This data has eleven fields per day and one calendar month per IBM 3480 cartridge. Archival of these tapes began in January 1979 and continues through the present. See Section 5.4.1 for a full description and format of this product.

The second type of Radiation Budget product is known as the Seasonal Radiation Budget. There are twenty fields per day and three calendar months per IBM 3480 cartridge, stacked by season (i.e., Winter - December through February, Spring - March through May, Summer - June through August, and Autumn - September through November). These twenty fields include everything that is contained on the Monthly Radiation Budget tapes plus more. Archival began with the June through August 1974 season and continues through the present. See Section 5.4.2 for a description and format of this product.

The third type of Radiation Budget product is the 10-year Mercator Radiation Budget product which is a subset of the Seasonal Radiation Budget. There are four fields per day mapped into a Mercator array and three IBM 3480 cartridges contain 10 years of non-contiguous data. The 10-year period includes from June 1974 through March 1978 (which uses the VHRR instrument from NOAA-3, 4, and 5), and January 1979 through February 1986 (using the AVHRR instrument on the TIROS-N series).

The fourth type of Radiation Budget product is the Monthly Mean Radiation Budget. There are forty-five months (June 1974 through February 1978) of mean radiation budget data (which were generated from the VHRR instrument on-board NOAA-3, -4, and -5) which are contained on two IBM 3480 cartridges. One cartridge contains data on Mercator grids and the other cartridge contains the same data on Polar Stereographic grids. The algorithm used to compute radiation budget parameters was changed after the generation of these tapes and these are the only RA/ASB Radiation Budget products which have not been corrected. The monthly mean data for the TIROS-N series are available from January 1979 through the present. See Section 5.4.3 for a description and format of this product.

The fifth and sixth types of radiation budget products are the seasonal mean and the annual mean. The seasonal mean consists of averages over each season while the annual mean consists of averages calculated over each calendar year. Both types of data have the same format as the monthly mean radiation budget product described in Section 5.4.3.

5.4.1 Monthly Radiation Budget Product

The format of the monthly radiation budget data has evolved over the years since it was first offered in January 1979 with the onset of TIROS-N polar orbiter data. The data between January 1979 and the end of September 1988 were created with a certain format and blocking scheme (herein referred to as the "Old" format). These data are described in Section 5.4.1.1. Beginning in July 1987, a new format accompanied by a new blocking scheme was introduced (herein referred to as the "New" format). These data are described in Section 5.4.1.2. However, there was a certain time period in which both formats were mixed on the archive tapes (July 1987 - September 1988) depending on whether the satellite was designated primary or secondary. Eventually, the "New" format was replaced with the NOAA KLM format after May 1999 (see Section 9.3.1.2 of the NOAA KLM User's Guide for the archive format). The following documentation attempts to record the logical progression of the monthly radiation budget data formats.

5.4.1.1 Old Monthly Radiation Budget format

The monthly radiation budget archive tape contains daily sets of radiation budget data fields for a calendar month. A daily set consists of both Polar Stereographic and 2.5 x 2.5 degree gridded mercator arrays of Nighttime Longwave Radiation, Daytime Longwave radiation, and Absorbed Solar Radiation. Polar Stereographic arrays of Available Solar Energy are also included.

Each daily set of data fields contains the following arrays stacked in the file in this order:

  1. Nighttime Longwave Radiation Northern Hemisphere Polar Stereo (125 x 125)
  2. Nighttime Longwave Radiation Southern Hemisphere Polar Stereo (125 x 125)
  3. Nighttime Longwave Radiation 2.5 x 2.5 degree (144 x 72)
  4. Daytime Longwave radiation Northern Hemisphere Polar Stereo (125 x 125)
  5. Daytime Longwave radiation Southern Hemisphere Polar Stereo (125 x 125)
  6. Daytime Longwave radiation 2.5 x 2.5 degree (144 x 72)
  7. Available Solar Energy Northern Hemisphere Polar Stereo (125 x 125)
  8. Available Solar Energy Southern Hemisphere Polar Stereo (125 x 125)
  9. Absorbed Solar Radiation Northern Hemisphere Polar Stereo (125 x 125)
  10. Absorbed Solar Radiation Southern Hemisphere Polar Stereo (125 x 125)
  11. Absorbed Solar Radiation 2.5 x 2.5 degree (144 x 72)

These daily sets of data fields are stacked chronologically on the tape, day by day (up to 31 days worth of data). All data values are contained in 2-byte integer words and are in units of W/m2 x 10. Missing data values are indicated by a value of -9999. The data values of Available Solar Energy are flagged with a minus sign at those grid points where the corresponding values of Absorbed Solar Energy are missing.

Each monthly radiation budget tape contains two files. The first file contains the data for the primary operational satellite and the second file contains data for the secondary operational satellite. The block size is 4000 bytes with record format VS (variable length records spanning block boundaries) and all records are 4000 bytes in length except for the records containing the remaining data in each array. Since the tape is written with the IBM VS option, the first 8 bytes of each 4000-byte physical record contain VS information and should be skipped by the non-IBM user. Table 5.4.1.1-1 shows the expected record lengths (which includes the 8-bytes of VS information) for the first three data arrays.

Table 5.4.1.1-1. Record length for first three data arrays in the Old Monthly Heat Budget data.
Record # # of Bytes Type of data array
1 4000 Nighttime Longwave Radiation Polar Stereo Northern Hemisphere (125 x 125)
2 4000
3 4000
4 4000
5 4000
6 4000
7 4000
8 3314
9 4000 Nighttime Longwave Radiation Polar Stereo Southern Hemisphere (125 x 125)
10 4000
11 4000
12 4000
13 4000
14 4000
15 4000
16 3314
17 4000 Nighttime Longwave Radiation Mercator (144 x 72)
18 4000
19 4000
20 4000
21 4000
22 784

In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125 array written row by row. These data are contained in 31,250-byte logical records. The data values fit the intersections of a square mesh overlaid on a Polar Stereographic projection. Array (63,63) lies on the Pole. The arrays for both hemispheres are oriented such that Array (63,1) represents the data at 0.4N, 100E in the Northern Hemisphere array and 0.4S, 80W in the Southern Hemisphere array.

Documentation for the Polar Stereographic arrays is contained in Table 5.4.1.1-2.

Table 5.4.1.1-2. Documentation for the Polar Stereographic arrays.
Location Contents
Array (1,1) Month
Array (2,1) Day
Array (3,1) Year
Array (4,1) Data type:
1=day flux
2=night flux
4=Available Solar Energy
5=Absorbed Solar Radiation
Array (5,1) Hemisphere:
1=Northern
2=Southern

The 2.5 x 2.5 degree gridded Mercator arrays contain data values that fit the intersection of a 2.5 degree latitude/longitude mesh that covers the globe. These arrays are contained in 20,736-byte logical records. The top row of 144 words contains documentation and the data values for the Poles. In the Absorbed Solar Radiation array, Array (27,1) through Array (99,1) contain values of Available Solar Energy for each 2.5 degree interval of latitude from 90N to 90S. The remaining 71 rows of 144 words each contain data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 data values in each row fit a latitude circle in which the first word contains the data value for 0E, the second word 2.5E, etc. Missing data have been filled in by interpolation and these values are flagged with a minus sign.

Documentation for the 2.5 x 2.5 degree Mercator arrays is contained in Table 5.4.1.1-3.

Table 5.4.1.1-3. Documentation for the 2.5 x 2.5 degree Mercator arrays.
Location Contents
Array (3,1) Year
Array (4,1) Month
Array (5,1) Day
Array (6,1) Data type:
1=day flux
2=night flux
4=Available Solar Energy
5=Absorbed Solar Radiation
Array (25,1) North Pole data value
Array (26,1) South Pole data value

5.4.1.2 New Monthly Radiation Budget Format

The monthly radiation budget (also known as the Radiation Budget monthly) data contains daily sets of Radiation Budget data fields for a calendar month. The data fields are copied from the Radiation Budget 37-day file in chronological order.

Each daily set of data contains Polar Stereographic hemispheric arrays and 2.5 x 2.5 degree global mercator arrays. The arrays contain data parameters which describe the three Radiation Budget quantities: Daytime Longwave Radiation, Nighttime Longwave Radiation, and Absorbed Solar Radiation. There are also Polar Stereographic hemispheric arrays of Available Solar Energy.

In addition to the arrays containing average values of the Radiation Budget quantities, there are arrays of Class Interval Populations and arrays of the variances of the values making up the averages.

A daily set of fields is made up of three subsets of arrays. Each subset contains data parameters which describe one of the Radiation Budget quantities. A daily set contains the following subsets:

  1. Nighttime Longwave Radiation
  2. Daytime Longwave Radiation
  3. Absorbed Solar Radiation
Each subset contains the following arrays:
  1. Northern Hemisphere Polar Stereo array of data values (125 x 125)
  2. Southern Hemisphere Polar Stereo array of data values (125 x 125)
  3. 2.5 x 2.5 degree Mercator array of data values (144 x 72)
  4. Northern Hemisphere Polar Stereo array of 1st Class Interval Pop. (125 x 125)
  5. Southern Hemisphere Polar Stereo array of 1st Class Interval Pop. (125 x 125)
  6. Northern Hemisphere Polar Stereo array of 2nd Class Interval Pop. (125 x 125)
  7. Southern Hemisphere Polar Stereo array of 2nd Class Interval Pop. (125 x 125)
  8. Northern Hemisphere Polar Stereo array of 3rd Class Interval Pop. (125 x 125)
  9. Southern Hemisphere Polar Stereo array of 3rd Class Interval Pop. (125 x 125)
  10. Northern Hemisphere Polar Stereo array of variances (125 x 125)
  11. Southern Hemisphere Polar Stereo array of variances (125 x 125)
  12. 2.5 x 2.5 degree Mercator array of variances (144 x 72)
The subset containing Absorbed Solar Radiation data differs from the others in that there are the following arrays at the beginning of the subset:
  1. Northern Hemisphere Polar Stereo array of Available Solar Energy (125 x 125)
  2. Southern Hemisphere Polar Stereo array of Available Solar Energy (125 x 125)
In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125 array written row by row. The data values fit the intersections of a square mesh overlaid on a Polar Stereographic projection. Array (63,63) lies on the Pole. The arrays for both hemispheres are oriented such that Array (63,1) represents the data at 0.4N, 100E in the Northern hemisphere array and 0.4S, 80W in the Southern Hemisphere array.

Documentation for the Polar Stereographic arrays is contained in Table 5.4.1.2-1.

Table 5.4.1.2-1. Documentation for the Monthly Polar Stereographic arrays.
Location Description
Array (1,1) Month
Array (2,1) Day
Array (3,1) Year
Array (4,1) Data Type:
1st digit (or only digit)
1 = Daytime Longwave Radiation
2 = Nighttime Longwave Radiation
4 = Available Solar Energy
5 = Absorbed Solar Radiation
2nd digit
6 = Class Interval Population
7 = Variance
3rd digit
1 = 1st Class Interval
2 = 2nd Class Interval
3 = 3rd Class Interval

The 2.5 x 2.5 degree arrays contain data values that fit the intersections of a 2.5 degree latitude/longitude mesh that covers the globe. The top row of 144 contains documentation and the values for the Poles. The remaining 71 rows, of 144 words each, contain data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 data values in each row fit a latitude circle where the first word contains the value for 0E longitude, the second word contains the value for 2.5E longitude, etc. In all the 2.5 x 2.5 degree arrays, missing data has been filled in by interpolation and all interpolated values are flagged with a minus sign.

The format for the documentation of the 2.5 by 2.5 degree arrays is contained in Table 5.4.1.2-2.

Table 5.4.1.2-2. Documentation in the Monthly 2.5 x 2.5 degree Mercator arrays.
Location Description
Array (3,1) Year
Array (4,1) Month
Array (5,1) Day
Array (6,1) Data type:
1 = Daytime Longwave Radiation
2 = Nighttime Longwave Radiation
3 = Absorbed Solar Radiation
Array (25,1) North Pole value
Array (26,1) South Pole value

The 2.5 x 2.5 degree array of Absorbed Solar Radiation contains values of Available Solar Energy in the top row. Beginning in Array (27,1) through Array (99,1) are the values of Available Solar Energy for each 2.5 degrees of latitude from 90N to 90S.

All data values and variances are in units of W/m2. All data values have been multiplied by 10. In all fields, missing data are indicated by -9999. All fields reside in INTEGER*2 (FORTRAN 77) arrays.

The data values in the Polar Stereographic arrays of Available Solar Energy are flagged with a minus sign at those grid points where the corresponding values of Absorbed Solar Radiation are missing.

In the Class Interval Population arrays of Outgoing Longwave radiation, the populations represent the following:

1st Class Interval = Values greater than 174
2nd Class Interval = Values from 136 through 174
3rd Class Interval = Values less than 136

In the Class Interval Population arrays of Absorbed Solar Radiation, the populations represent the following:

1st Class Interval = Values greater than 150
2nd Class Interval = Values from 100 through 150
3rd Class Interval = Values less than 100

The Class Interval Populations are biased with a value of -9000. Missing data is indicated with a value of -9999. A value of 9000 must be added to all values greater than -9999 in order to obtain the true population.

Each 125 x 125 Polar Stereographic array is written to tape in six segments. The first five segments contain 21 rows (5,250 bytes), and the sixth segment contains 20 rows (5,000 bytes).

Each 144 x 72 mercator array is written to tape in four segments of 18 rows each (5,184 bytes).

Table 5.4.1.2-3 shows how the data in the New format are blocked on the tape.

Table 5.4.1.2-3. Blocking of data for the Monthly Radiation Budget.
Record # # of Bytes
Nighttime Longwave radiation Polar Stereo Northern Hemisphere (125 x 125)
1 4000
2 1266
3 4000
4 1266
5 4000
6 1266
7 4000
8 1266
9 4000
10 1266
11 4000
12 1016
Nighttime Longwave Radiation Polar Stereo Southern Hemisphere (125 x 125)
13 4000
14 1266
15 4000
16 1266
17 4000
18 1266
19 4000
20 1266
21 4000
22 1266
23 4000
24 1016
Nighttime Longwave Radiation Mercator (144 x 72)
25 4000
26 1200
27 4000
28 1200
29 4000
30 1200
31 4000
32 1200

Radiation budget data collected between July 1987 and July 1988, had two files which were not only blocked differently, but were also formatted differently. File 1 contained radiation budget data for the primary satellite (NOAA-9) in the old format and was blocked as shown in Table 5.4.1.1-1, while File 2 which contained radiation budget data for the secondary satellite (NOAA-10) in the new format was blocked as shown in Table 5.4.1.2-3. This confusing situation finally ended when NOAA-9 was replaced by NOAA-11 as the primary satellite in October 1988. At that time, the new format was used for both operational satellites.

From October 1988 through May 1999, monthly radiation budget data have had both files blocked as shown in Table 5.4.1.2-3.

5.4.2 Seasonal Radiation Budget Product

The Seasonal Radiation Budget archive tape contains 90 - 92 daily data sets. A daily data set consists of four radiation fields written in the following order: 1) Daytime Outgoing Longwave, 2) Absorbed Solar Energy, 3) Available Solar Energy, and 4) Nighttime Outgoing Longwave. Each radiation field consists of five arrays in the following order: 1) Northern hemisphere Polar Stereographic, 2) Southern Hemisphere Polar Stereographic, 3) Northern Hemisphere Polar Chip, 4) Southern Hemisphere Polar Chip, and 5) a latitude/longitude Mercator grid. These data are available from June 1974 through May 1999.

Each daily data set contains the following arrays in the indicated order:

  1. Day Flux Northern Hemisphere. 125 x 125 array
  2. Day Flux Southern Hemisphere. 125 x 125 array
  3. Day Flux Northern Hemisphere. Chip 45 x 45 array
  4. Day Flux Southern Hemisphere. Chip 45 x 45 array
  5. Day Flux Mercator 144 x 72 array
  6. Absorbed Solar Energy Northern Hemisphere. 125 x 125 array
  7. Absorbed Solar Energy Southern Hemisphere. 125 x 125 array
  8. Absorbed Solar Energy Northern Hemisphere. Chip 45 x 45 array
  9. Absorbed Solar Energy Southern Hemisphere. Chip 45 x 45 array
  10. Absorbed Solar Energy Mercator 144 x 72 array
  11. Available Solar Energy Northern Hemisphere. 125 x 125 array
  12. Available Solar Energy Southern Hemisphere. 125 x 125 array
  13. Available Solar Energy Northern Hemisphere. Chip 45 x 45 array
  14. Available Solar Energy Southern Hemisphere. Chip 45 x 45 array
  15. Available Solar Energy Mercator 144 x 72 array
  16. Nighttime Flux Northern Hemisphere. 125 x 125 array
  17. Nighttime Flux Southern Hemisphere. 125 x 125 array
  18. Nighttime Flux Northern Hemisphere. Chip 45 x 45 array
  19. Nighttime Flux Southern Hemisphere. Chip 45 x 45 array
  20. Nighttime Flux Mercator 144 x 72 array
In the Polar Stereographic form, each hemisphere of data is contained in a 125 x 125 array written row by row. The data values fit the intersections of a square mesh overlaid on a Polar Stereographic projection. Array (63,63) lies on the Pole. The arrays for both hemispheres are oriented such that array (63,1) is at latitude 0.4N and longitude 100E in the Northern Hemisphere array and at latitude 0.4S and longitude 80W in the Southern Hemisphere array.

The documentation in the Polar Stereographic arrays is contained in Table 5.4.2-1.

Table 5.4.2-1. Documentation in the Seasonal Polar Stereographic arrays.
Location Description
Array (1,1) Month
Array (2,1) Day
Array (3,1) Year
Array (4,1) Data type:
1 = Day Flux
2 = Night Flux
4 = Available Solar Energy
5 = Absorbed Solar Energy
Array (5,1) Hemisphere:
1 = Northern
2 = Southern

The Polar Stereographic chips are the center portion of the complete 125 x 125 Polar Stereographic arrays. The 45 x 45 chip arrays are written row by row and oriented in the same manner as the larger Polar Stereographic arrays. The chips contain no documentation. Missing data have been filled in by interpolation and all interpolated values are flagged with a minus sign.

The Mercator arrays contain data values that fit the intersections of a 2.5 degree latitude/longitude mesh that covers the globe. The top row of 144 words (1 word = 2 bytes) contains documentation. The remaining 71 rows of 144 words each contain data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 word data values in each row fit a latitude circle where the first word contains the data value for 0E, the second word 2.5E, etc. Missing data are handled in the same manner as described in the Polar Stereographic chips.

The documentation in the 144 X 72 Mercator arrays is contained in Table 5.4.2-2.

Table 5.4.2-2. Documentation in the Seasonal 144 x 72 Mercator arrays.
Location Description
Array (3,1) Year
Array (4,1) Month
Array (5,1) Day
Array (6,1) Data type
Array (7,1) - (10,1) Satellite name in BCD
Array (25,1) North Pole data value
Array (26,1) South Pole data value

All data are stored in 2 byte (16 bit) words and recorded in binary. All data values are in units of W/m2 and have been multiplied by 10 before they are stored. The data values of Available Solar Energy are flagged with a minus sign at those grid points where the corresponding values of Absorbed Solar Energy are missing or have been interpolated. Missing data is indicated by a value of -999910. Note: the record format VS option was used to create the CCT (See Section 5.4.1 for further explanation).

5.4.2.1 10-Year Mercator Radiation Budget Product

The 10-Year Mercator Radiation Budget product consists of daily data sets in Mercator form spanning approximately ten-years (non-contiguous). This product is a subset of the Seasonal Radiation Budget product. The daily data contain the following arrays in the indicated order:

  1. Day flux Mercator 144 x 72 array
  2. Absorbed Solar Energy Mercator 144 x 72 array
  3. Available Solar Energy Mercator 144 x 72 array
  4. Nighttime Flux Mercator 144 x 72 array
The Mercator arrays and data values are structured exactly the same as the Mercator arrays described in Section 5.4.2. However, the documentation in the 144 x 72 Mercator arrays differs slightly and has the format shown in Table 5.4.2.1-1.

Table 5.4.2.1-1. Format of documentation for the 144 x 72 Mercator Arrays.
Location Content
Array (3,1) Year
Array (4,1) Month
Array (5,1) Day
Array (6,1) Data Type:
1=Day Flux
2=Night Flux
4=Available Solar Energy
5=Absorbed Solar Energy
Array (25,1) North Pole data value
Array (26,1) South Pole data value

Three IBM 3480 cartridges contain the data as follows:

  1. June 1, 1974 - March 16, 1978 (Pre TIROS-N satellites, NOAA-3, 4, 5)
  2. January 1, 1979 - November 30, 1982 (TIROS-N series)
  3. December 1, 1982 - February 28, 1986 (TIROS-N series)
These non-labeled archive tapes were created using the record format VS option and a block size of 4000.

5.4.3 Monthly Mean Radiation Budget Products

Two formats exist for the Monthly Mean Radiation Budget Products. Basically, the only difference is that the older format separated the two projections (Mercator and Polar Stereographic) onto two different archive tapes, while the current format combines both projections on the same archive tape. The current format began on October 1, 1987 and continued through May 1999. This format is described in Section 5.4.3.1. The one used for the period ending on September 30, 1987, is described in Section 5.4.3.2.

5.4.3.1 Monthly Mean Radiation Budget Products (October 1, 1987 through May 1999)

The Monthly Mean Radiation Budget archives contain Monthly Mean data in 2.5 x 2.5 degree latitude/longitude grid called a Mercator Array and a 45 x 45 grid on a Polar Stereographic map base. The mean data are derived from the daily archived arrays for each calendar month. The Monthly Mean data set begins with November 1988. A Monthly Mean data set consists of four groups of three (12 total) Radiation Fields. The groups are written in the following order: Daytime Outgoing Longwave Radiation, Nighttime Outgoing Longwave Radiation, Absorbed Solar Energy and Available Solar Energy. Each group of three fields consist of a Northern Hemisphere polar stereo (45 x 45) chip, a Southern Hemisphere chip, and a 144 x 72 Mercator field.

Thus, the twelve Radiation Fields are stored in the following order:

1. Daytime Flux Northern Hemisphere 45 x 45 Array
2. Daytime Flux Southern Hemisphere 45 x 45 Array
3. Daytime Flux Mercator 144 x 72 Array
4. Nighttime Flux Northern Hemisphere 45 x 45 Array
5. Nighttime Flux Southern Hemisphere 45 x 45 Array
6. Nighttime Flux Mercator 144 x 72 Array
7. Absorbed Solar Energy Northern Hemisphere 45 x 45 Array
8. Absorbed Solar Energy Southern Hemisphere 45 x 45 Array
9. Absorbed Solar Energy Mercator 144 x 72
10. Available Solar Energy Northern Hemisphere 45 x 45 Array
11. Available Solar Energy Southern Hemisphere 45 x 45 Array
12. Available Solar Energy Mercator 144 x 72 Array

The 45 x 45 Polar Stereographic Array covers the area of 50N to 90N and 50S to 90S. The 45 x 45 Arrays are written row by row. The data values fit the intersections of a square mesh overlaid on a Polar Stereographic projection. Array (23,23) lies on the Pole. The arrays for both hemispheres are oriented such that Array (23,1) is at latitude 50.4N and longitude 80W in the Northern Hemisphere Array and at latitude 50.4S and longitude 80W in the Southern Hemisphere Array. The chips contain no documentation. Missing data have been filled in by interpolation and all interpolated values are flagged with a minus sign.

The Mercator Arrays contain data values that fit the intersections of a 2.5 degree latitude/longitude mesh that covers the globe. The top row of 144 words (1 word = 2 bytes) contains documentation. The remaining 71 rows of 144 words each contain data for the latitude circles at 2.5 degree intervals from 87.5N to 87.5S. The 144 word data values in each row fit a latitude circle where the first word contains the data value for 0E, the second word 2.5E, etc. Missing data are handled in the same manner as described for the Polar Stereographic Arrays.

The documentation in the 144 x 72 Mercator Arrays is contained in Table 5.4.3.1-1.

Table 5.4.3.1-1. Format of documentation for the 144 x 72 Mercator Arrays.
Location Content
Array (3,1) Year
Array (4,1) Month
Array (5,1) Day
Array (6,1) Data Type:
1=Day Flux
2=Night Flux
4=Available Solar Energy
5=Absorbed Solar Energy
Array (7,1) Number of days averaged
Array (25,1) North Pole data value
Array (26,1) South Pole data value

All data are stored in IBM 4 byte (REAL*4) words and recorded in binary on IBM 3480 cartridges. All data values are in units of W/m2. The data values of Available Solar Energy are flagged with a minus sign at those grid points where the corresponding values of Absorbed Solar Energy are missing or have been interpolated.

5.4.3.2 Monthly Mean Radiation Budget Products (before October 1,1987)

The Monthly Mean Radiation Budget archive tapes consist of two CCTs, one CCT contains the monthly mean data in 2.5 x 2.5 degree Mercator form and the other contains the data in Polar Stereographic form. Section 5.4.3.1 describes the format of the Mercator form and Section 5.4.3.2 contains the format of the Polar Stereographic form.

5.4.3.2.1 Monthly Mean Radiation Budget (2.5 x 2.5 degree Mercator arrays before October 1, 1987)

The Monthly Mean Radiation Budget product in Mercator form contains 45 sets of monthly mean Radiation Budget data. The mean data are derived from the daily archived arrays for the calendar months. Each set consists of four arrays in the following order: 1) Day IR Flux, 2) Night IR Flux, 3) Absorbed Solar Energy, and 4) Available Solar Energy. Each array contains 144 X 72 words. The data are stored in one file consisting of 180 records (4 arrays x 45 sets). The documentation and data values for the Poles for each array are contained in the first row of 144 words as shown in Table 5.4.3.2.1-1.

Table 5.4.3.2.1-1. Documentation and data values for the poles for each array.
Location Contents
Array (1,1) Null
Array (2,1) Null
Array (3,1) Year of beginning date
Array (4,1) Month of beginning date
Array (5,1) Day of beginning date
Array (6,1) Data type:
1=Day IR Flux
2=Night IR Flux;
4=Available Solar Energy
5=Absorbed Solar Energy
Array (7,1) Number of days used to compute mean
Array (8,1) Month of ending date
Array (9,1) Day of ending date
Array (10,1) Year of ending date
Array (25,1) North Pole data value
Array (26,1) South Pole data value

The first set of data contains June 1974 and the 45th set contains February 1978 data with all data sets in between ordered chronologically. The data value for each location has been derived by a four-point smoothing routine from the 125 x 125 hemispheric arrays (See Section 5.4.1) to represent the center of a 2.5 x 2.5 degree grid square. All data are recorded as 32-bit floating point words and are in units of W/m2. Again, the record format VS option was used to create this CCT (See Section 5.4.1) for further explanation).

5.4.3.2.2 Monthly Mean Radiation Budget (Polar Stereographic arrays before October 1, 1987)

The Monthly Mean Radiation Budget product in Polar Stereographic form contains 45 set of monthly mean Radiation Budget data. A set consists of two hemispheric arrays for each of four data types. Each hemispheric array contains 125 words per row for 125 rows. The sequence of arrays per set is:

1. Day Flux, Northern Hemisphere
2. Day Flux, Southern Hemisphere
3. Night Flux, Northern Hemisphere
4. Night Flux, Southern Hemisphere
5. Absorbed Solar Energy, Northern Hemisphere
6. Absorbed Solar Energy, Southern Hemisphere
7. Available Solar Energy, Northern Hemisphere
8. Available Solar Energy, Southern Hemisphere

The documentation is contained in the first five words (16 bits) of the first row in each 125 x 125 array. Table 5.4.3.2.2-1 describes the documentation.

Table 5.4.3.2.2-1. Documentation in Polar Stereographic projection.
Location Contents
Array (1,1) Month
Array (2,1) Number of days in the mean
Array (3,1) Year, expressed in units and tens only
Array (4,1) Data Type:
1=Day Flux
2=Night Flux
4=Available Solar Energy (ASE)
5=Absorbed Solar Energy
Array (5,1) Hemisphere:
1= Northern
2=Southern

Each 125 x 125 array represents a square mesh overlaid on a Polar Stereographic projection of the relevant hemisphere. Array (63,63) lies on the pole of that hemisphere. Array (1,63) is located 0.4 degrees poleward of the equator and 170W, while Array (125,1) is 0.4 degrees poleward at longitude 10E. Array (63,1) is located at 0.4N, l00E for the Northern hemisphere array and at 0.4S, 80W for the Southern hemisphere array.

All data are 16-bit integer words and are in units of W/m2. The data and documentation words are multiplied by 10 before storing. All the data are contained in one file. Note: The record format VS option was used to create this CCT (see Section 5.4.1 for further explanation).

Amended June 17, 1999
Amended December 10, 1999



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