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GENERAL (USER SERVICES) FAQ


How much does it cost to get data from the GES DISC?

All of the data products and services provided by the GES DISC are available free of any charges.


Where are the MODIS NDVI / Land/ Fire data?

MODIS land surface data are archived at the Land Processes DAAC (LPDAAC). Here is the contact information for the LPDAAC:

http://edcdaac.usgs.gov/main.asp

LP DAAC User Services
U.S. Geological Survey (USGS)
Center for Earth Resources Observation and Science (EROS)
47914 252nd Street
Sioux Falls, SD 57198-0001 USA
605-594-6116 voice
605-594-6963 fax

email: LPDAAC@eos.nasa.gov


Where are the AVHRR NDVI data?

The GES DISC AVHRR data products are no longer supported nor distributed by the GES DAAC facility. This includes all HDF tape products and FTP binary products. We are pleased to inform you that the Global Land Cover Facility (GLCF) at the University of Maryland is now the public site for providing AVHRR data and support services. URL: http://glcf.umiacs.umd.edu/data/gimms/.


II cannot find the MODIS atmospheric data. Can you tell me their location?

MODIS atmospheric data are now available from the LAADS Web, http://ladsweb.nascom.nasa.gov/. Note the differences in spelling between LAADS Web and "ladsweb" in the URL.


Do the answers to these FAQ entries represent the official position or opinion of NASA?

No. The answers to these questions are provided to assist you with the use of the data in the GES DISC archives, and the related tools we provide. Many of these answers will guide you to other NASA Web sites and data archives, which are part of the NASA network. For our users, we strive to provide pertinent and correct information to assist with their scientific research.


What is Mirador for? Is it better than Google?

Mirador is a simplified interface for finding Earth science data files at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Because Mirador is dedicated to and designed for the data archived at the GES DISC, it works better than a general Google search to find data files in the GES DISC system, especially for specific space or time criteria. You can find some answers to questions about Mirador at the URL below:

http://mirador.gsfc.nasa.gov/cgi-bin/mirador/help.pl

Mirador actually employs Google search technology for keyword-based searches.


Where are the MODIS ATBDs? Are they current and still useful?

The MODIS ATBDs (Algorithm Theoretical Basis Documents) can still be found on the MODIS Web:

http://modis.gsfc.nasa.gov/data/atbd/index.php

Under each discipline, the latest revision date is listed next to the ATBD title in the table listing. Some of the ATBDs have been revised; others have not been revised, but the basic algorithm described in the document is still in use. Other ATBDs (notably for the MODIS Ocean products) may no longer apply to the products which are available, but the ATBD may still contain useful reference information. If the information in an ATBD is to be utilized for research, it would be wise to contact the authors (if possible) to determine the current status of the algorithms used to generate MODIS geophysical data products.


How can I make the "DownThemAll" Mozilla plugin work effectively for downloads of GES DISC data?

Users attempting to employ the "DownThemAll" Mozilla plug-in who are experiencing difficulties with data downloads should consider the following suggested changes to the default preferences for this plug-in:

  • The Multipart download capability should be disabled.  Set Max. number of segments per download to 1 in the Multipart download item, under the Advanced tab in the Preferences window.
 
  • Concurrent downloads should be disabled.  Set max concurrent downloads to 1 in the Download item, under the Main tab of the Preferences window.
 
  • Users experiencing network dropouts might consider enabling Auto Retries (also under the Main tab of the Preferences window) by setting Retry each to 30 minutes, and Max. Retries to 10.

Do you have maps or data regarding surface solar radiation or solar irradiance?

The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) archives satellite-based observations as well as model-assimilated surface solar irradiance data or shortwave radiation (also referred as 'insolation'). The model data on our site refers to the assimilation data product of atmospheric, land, and ocean observations from satellites, aircraft, ships, and other sources that are assimilated at various time scales.

The GES DISC has model-assimilated surface solar radiation data products from the Global Land Data Assimilation models (GLDAS):

http://disc.sci.gsfc.nasa.gov/hydrology/data-holdings/parameters

http://disc.sci.gsfc.nasa.gov/hydrology/data-holdings/hydro_get_data.shtml

and from atmospheric reanalysis and assimilation model runs (e.g MERRA): http://disc.sci.gsfc.nasa.gov/mdisc/

For user convenience, most of the satellite and model-assimilated data have been made available from our Web-based, on-line visualization system called Giovanni.

Giovanni users can display global or selected regional data as color images, generate time series, correlate different parameters using scatter plots and download the results. For visualization of incoming surface solar flux, utilize the MERRA Giovanni instance.

Even though the GES DISC has surface solar data from model assimilation (GLDAS and MERRA), we also recommend:

Surface radiation budget (SRB) data, available from NASA Langley Research Center.

Another source of these data is NASA Langley's Surface meteorology and Solar Energy (SSE) site:

http://eosweb.larc.nasa.gov/sse/.

The SSE data set contains parameters formulated for assessing and designing renewable energy systems. Parameter definitions are available from the site (search for surface insolation)

http://www.geocities.com/~dmdelaney/Ottawa-solar-data/NASA-SSE-parameter-definitions.htm.

On-line plotting capabilities allow quick evaluation of potential renewable energy projects for any region of the world. The SSE data set is formulated from NASA satellite- and reanalysis-derived insolation and meteorological data for the 22-year period of July 1983 - June 2005.  The SSE site also provides data and maps for almost 1200 ground sites with visualization capabilities.

It is also possible to generate time series of radiation for Tilted Flat-Plate Collectors from the Solar and Wind Energy Resource Assessment (SWERA) project site, funded by NASA, the United Nations and other international organisations.  Data mapping capabilities are available at the following location:  http://na.unep.net/swera_ims/map/

 


 

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  • Last updated: August 11, 2009 19:46:43 GMT