# Presentation: 830268

## MODIS and SeaWiFS Data at Diagnostic Data Sites From GES DAAC

- I

**Ocean Color Diagnostic Data Sites**

- In January 2001, about 23 diagnostic data sites for space borne ocean color sensors were selected at the 4th  Sensor Intercomparison and Merger for Biological and Interdisplinary Oceanic Studies (SIMBIOS) meeting, based on discussions in previous meetings to aid in data comparison and algorithm development.  In addition, diagnostic data was designated for collection at the CIMEL sun-photometer sites, as well as at selected Atmospheric Radiation Measurement (ARM) sites.  The spatial size of the diagnostic sites varies from about 50km x 100km to 400km x 400km.  MODIS and SeaWiFS Cutouts were created by SIMBIOS Project as inputs to the diagnostic data sets.  The Cutouts are subsets of MODIS (Level 1B and Level 2) and SeaWiFS (Level 1A and Level 2) data products that cover each diagnostic data site.  The data are currently archived at the GSFC Earth Sciences Distributed Active Archive Center (GES DAAC).

**Suhung Shen ****1****,   Andrey Savtchenko ****2**** ,   James G. Acker ****3****,   Irina Gerasimov ****3****,   SIMBIOS ****4**
- 1 George Mason University/GES DAAC             2 L3 Communications/GES DAAC	3 Science System Application Inc./GES DAAC            4 NASA SIMBIOS Project

**SS7.01 333**
**ASLO/TOS  2004**

**SITE LOCATIONS**

- Six MODIS and SeaWiFS Cutouts are archived at the GES DAAC. Although the nadir spatial resolution is 1 km, spatial resolution in the Cutouts varies due to the variable position of the diagnostic site in the satellite’s scan swath. The subset formats of MODIS and SeaWiFS products are geographically different. MODIS Cutouts were created from the original 5-minute data granules, so subset boundaries are aligned with longitude and latitude lines.  SeaWiFS Cutouts were created from Local Area Coverage (LAC) products acquired from HRPT stations or the on-board data recorder,  so that the subset boundaries will be aligned with the satellite scanning direction and orbital inclination. The following table gives a brief summary of  the Earth Science Data Type (ESDT) name of the Cutouts, sensors, data format, and original product name.  Detailed information about MODIS and SeaWiFS data are available at: **http://daac.gsfc.nasa.gov**

**HDFLook**  is a new multifunctional GES DAAC data processing and visualization tool for MODIS Radiometric and Geolocation, Atmosphere, Ocean and Land data. The main features of HDFLook are visualization and remapping swath data to world map;  geo-projection; spatial, parameter, and channel subsetting; multiple granule mosaic and stitch capabilities; data conversion from HDF-EOS to HDF, ASCII, Binary, JPEG, and Geo-TIFF.  It is developed for XWindows computer environment and has been tested on SGI and Linux systems. Latest update and information about this product is available at: **http://daac.gsfc.nasa.gov/MODIS/HDFLook**
**SeaDAS** is a comprehensive ocean color data visualization and analysis package and is originally designed for the processing, display, analysis, and quality control of all SeaWiFS data products. The SeaDAS software has been enhanced recently to display MODIS ocean color products for all levels and to process MODIS-Aqua Level 1A and Level 1B data to Level 2 and Level 3 “SeaWiFS like” products. The most new release can be downloaded from:
**http://seadas.gsfc.nasa.gov/**
**SIMAP**** **is an GES DAAC-developed, IDL based script that is designed to read and map MODIS Level 1B and Level 2 Ocean and Atmosphere products.  One strength of SIMAP is the composition of global maps, or a stitching multiple granules onto a single world map. The software can be found at:
**http://daac.gsfc.nasa.gov/MODIS/simap/**
**HDFView**  is a Java-based tool for browsing and editing NCSA HDF4 and HDF5 files.  It was implemented by using JavaTM 2 Platform that is designed to be machine-independent.  The document and software can be downloaded from:
**http://hdf.ncsa.uiuc.edu/hdf-java-html/hdfview/**
**HEG**** **is a data format converter, which converts many EOS products written in HDF-EOS to GeoTIFF, native binary or HDF-EOS Grid. It also has reprojection, resampling, subsetting, stitching (mosaics), and metadata creation capabilities. The tool is accessible via a command line interface or by a GUI. The tool is operable on Sun, SGI, Windows, and Linux platforms.  The detailed information and latest update is available at:
**http://hdfeos.gsfc.nasa.gov/hdfeos/details.cfm?swID=59**

| Cutouts
ESDT | Sensor | Process
Level | Data 
Format | Original  ESDT |
| --- | --- | --- | --- | --- |
| MODOCCL2 | MODIS Terra | Level 2 | HDF-EOS | MODOCL2, MODOCL2A, MODOCL2B, MODOCQC, MOD28L2 |
| MOD02CL1 | MODIS Terra | Level 1B | HDF-EOS | MOD021KM |
| MYDOCCL2 | MODIS Aqua | Level 2 | HDF-EOS | MYDOCL2, MYDOCL2A, MYDOCL2B, MYDOCQC, MYD28L2 |
| MYD02CL1 | MODIS Aqua | Level 1B | HDF-EOS | MYD021KM
 |
| SWFOCCL2 | SeaWiFS | Level 2 | HDF | Level-2 LAC |
| SWFCL1A | SeaWiFS | Level 1A | HDF | Level-1A LAC |

**VISUALIZATION AND ANALYSIS TOOLS**

- The Cutouts data were created at 39 diagnostic data sites, as implemented by SIMBIOS, based on recommendations of the SIMBIOS Science Team and the IOCCG.

**DATA ACCESS**

**Diagnostic data sample images from SIMBIOS Diagnostic Data Set Browser http://seawifs.gsfc.nasa.gov/cgi/seawifs_region_extracts.pl?TYP=ocean**

**SeaWiFS Level 1A True Color**

**MODIS Terra Level 2 chlor_a_2 **

**SeaWiFS Level 2 chlor_a**

**MODIS Aqua Level 2chlor_a_2**

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- The MODIS and SeaWiFS diagnostic data sets can be ordered from the GES DAAC data search and order system at:
**http://daac.gsfc.nasa.gov/data/dataset/MODIS/03_Ocean/index.html**
**http://daac.gsfc.nasa.gov/data/dataset/MODIS-Aqua/03_Ocean/index.html**
- and from the Earth Observing System Data Gateway (EDG):
**http://redhook.gsfc.nasa.gov/~imswww/pub/imswelcome/**
- SeaWiFS diagnostic data sets are also available from the SIMBIOS Diagnostic Data Set Browser:
**http://seawifs.gsfc.nasa.gov/cgi/seawifs_region_extracts.pl?TYP=ocean**
- If you have any order problem or questions, please contact Goddard DAAC Help Desk at: **301-614-5224** or **1-877-422-1222** or
- e-mail: **help@daac.gsfc.nasa.gov**

- Besides MODIS and SeaWiFS Cutouts at diagnostic data sites, the GES DAAC ordering system provides other pre-subsetted products and on-demand subsetting services for some MODIS and SeaWiFS products. The original data file sizes are quite large, so these subsetting services will provide considerable time-savings in both data transfer and preprocessing.
**MODIS Level 3 and Level 4 Mapped Ocean Product Spatial Subsetting:**
- This is an on-demand subsetting service. Users can order data by specifying parameters and boundaries. The order system will subsample the data and send users only the data they need.  This function is available in ordering data from both archive and Data Pool. Subsampled data may be immediately downloaded if ordering from the Data Pool.
**MODIS Level 2 Ocean Product Parameter Subsetting:**
- This is another on-demand subsetting service.  By selecting physical parameters from the order page, users will receive data files with only parameters they have selected.
**MODIS Level 1A Ocean Bands Product:**
- This is a pre-subsetted product that contains data from ocean bands only.  The data were extracted from original MODIS Level 1 files. This product is available from both archive and Data Pool.
**SeaWiFS Level 1A HRPT Subsetted Data:**
- This is a pre-subsetted SeaWiFS HRPT product that  covers 14 popular areas of  interest, such as the U.S. Gulf Coast and Florida, Black Sea, Mediterranean Sea, Yellow Sea,  and others.

**INTRODUCTION**

**PRODUCT DESCRIPTION**

**OTHER SUBSETTING SERVICES at GES DAAC**