FREQUENTLY ASKED QUESTIONS (FAQ)

All of the questions listed here are linked directly to the answers on the respective FAQ pages. Just click on the question to access the answer. To go to the full FAQ page, click on the title.

AIRS

• What do the time values in AIRS L1 and L2 data products represent?
• Why can't I get monthly AIRS data the day after the month is over?

General Questions (User Services)

• How much does it cost to get data from the GES DISC?
• Where are the MODIS NDVI / Land/ Fire data?
• Where are the AVHRR NDVI data?
• I cannot find the MODIS atmospheric data. Can you tell me their location?
• Do the answers to these FAQ entries represent the official position or opinion of NASA?
• What is Mirador for? Is it better than Google?
• Where are the MODIS ATBDs? Are they current and still useful?

Giovanni

• Why are there gaps in a daily Level 3 data file?
• How can I put a Giovanni output image into Google Earth?
• How do I acknowledge the use of Giovanni in a research paper? If I use Giovanni should I have someone on the GES DISC staff as a co-author?
• How do I subscribe to the Giovanni-News mailing list?

Hydrology DISC

• What are the GLDAS products?
• What are the differences among LDAS, NLDAS, and GLDAS?
• What is the GRIB format? How can I interpret it?
• Why should I use GRIBTAB files to decode the GRIB files?
• What are the land surface models used in GLDAS?
• Can I obtain the source codes for the land surface models?
• Can I obtain the forcing dataset that was used in GLDAS?
• Can I obtain the land surface parameter data sets used in GLDAS?
• What’s the GrADS Data Server?
• Can you give an example of retrieving GLDAS data via GDS?

Laboratory for Ocean Color Users (LOCUS)

• I am looking for all the MODIS Ocean data products. Why doesn't the GES DISC have them, and can I get them anywhere else?
• Can I see a tsunami in ocean color data from SeaWiFS or MODIS?

Precipitation

• I am using the 3-hourly 3B42-V6 rainfall rates from TRMM. How can I convert these 3-hourly rainfall rate (mm/hour) to total daily rainfall (mm/day)?
• What are the values for latitude and longitude in TRMM 3B42 and 3B43 HDF data files?
• Where can I find more information on the TRMM Data Set?
• How current are the TRMM data?
• What is the GES DISC/DAAC Search and Order Web Interface?
• Where can I find some documentation describing TRMM and TRMM data?
• Where can I find some information describing the TRMM algorithms?
• I would like to receive all new files generated for a data product, over a given time period, at a specified time interval (e.g., weekly). Can I set up a procedure by which specified data will be sent to me automatically?
• How are the daily products computed from 3B42RT and Version 6 3B42 in TOVAS (the TRMM Online Visualization and Analysis System)?
• What’s the key documentation describing the 3B42RT and Version 6 3B42 products?
• What’s the difference between the real time and research products of the TRMM Multi-satellite Precipitation Analysis (TMPA)?
• What are the caveats in using TRMM Multi-satellite Precipitation Analysis (TMPA) products?

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