The processing code was originally written in a combination of RATFOR, FORTRAN 77 and C. However, to meet EOSDIS requirements, the code was converted to FORTRAN 90 and C using an automated translator. The implication of this is that the resulting code may be difficult to follow.
A number of toolkits are required to accompany the MODIS Ocean processing code :
The SDP toolkit may be obtained via anonymous ftp to edhs1.gsfc.nasa.gov (password required); to enquire about obtaining the password, please email: pgstlkit@eos.hitc.com. This toolkit is currently compatible with the Silicon Graphics IRIX 6.5.3.
The program was designed (at RSMAS, Miami) for use with Silicon Graphics IRIX 6.5.3 Power Challenge, 200 MHz, R10,000 processor, 1 CPU computers, using version 7.2.1.3 IDO of the compilers. The program is expected to be portable to other platforms (such as Digital UNIX and SUN), however complete testing has not yet been made. The type of floating point number usage can be changed in ocean_build.csh or ocean_build.ksh by setting the variable BRAND to sgi (old-style 32 bit), sgi32 (new-style 32 bit) or sgi64 (64 bit). The memory requirement is 70 Mb for processing visible wavelength data, 360 Mb for the level 2 binning, and 580 Mb for the level 4 mapping.
The MODIS ocean processing will take place at the Goddard DAAC. This facility will be used to perform standard, real-time processing. Facilities also exist at RSMAS, Miami, for ocean processing. The RSMAS facility will be used to perform vicarious calibration and algorithm testing.
The delivered routines uncompress and untar to 4.5 Gb (130 Mb in STORE, 4.4 Gb in RUN).
Data is processed in 5 minute satellite data granules. The table below (from ATBD 26, Apr 99) summarizes the processing times for the different components of the code.
| Process | CPU hours per data-day produced | number of processors |
| Ocean color: Level 2 and space binning | 20 | 8 |
| Sea surface temperature: Level 2 and space binning | 20 | 2 |
| Level 3 40 daily binned products and 3 map resolutions | 20 | 3 |
| De-cloud 40 daily products and creation of 3-week reference | 20 | 3 |
The following table summarizes the output files generated by the code each day (adapted from ATBD 26, Apr 99).
| files/day | Mb/file | Gb/day | |
|---|---|---|---|
| Level 2 | |||
| ocean color data | 432 | 160 | 68 |
| ocean color QC | 144 | 198 | 29 |
| SST data | 288 | 44 | 13 |
| SST QC | 288 | 124 | 36 |
| Level 3 (daily, 4.6 km) | |||
| ocean color 36 products | 36 | 620 | 22 |
| SST 2 products (day and night) | 4 | 640 | 3 |
| Level 3 (weekly, 4.6 km) | |||
| ocean color | 5 | 620 | 3 |
| SST | 1 | 640 | 0.3 |
| Level 4 (EOS grid) | |||
| 4.6 km daily | 293 | 134 | 22 |
| 36 km daily | 293 | 2 | 0.3 |
| 1 degree daily | 293 | 0.3 | 0.05 |
| 4.6 km weekly | 37 | 134 | 3 |
| 36 km weekly | 37 | 2 | 0.05 |
| 1 degree weekly | 37 | 0.3 | 0.01 |
| Total | 2188 | 197 |
This documentation refers to version 2.0 of the software. This version of the code is delivered to NASA/GSFC, a Distributed Active Archive Center (DAAC) and is the at-launch version (internally, they refer to this version as version 2.1.0 for MODCOL and MODSST). For the current delivery status of this code, please see the Code Status web page. Minor revisions to the software may be made before launch. The entries in the lookup tables (ancillary data of the algorithm coefficients, etc.) may also be changed as required.
If you would like to obtain a copy of the MODIS ocean processing code, please contact Bob Evans at RSMAS, University of Miami.
Documented by Jasmine S. Bartlett, COAS, Oregon State University.