NSIDC NOTES  -  Issue No. 48 SUMMER 2004


In this Issue:


Products & Services

NSIDC's Snow Extent Data Used to Assess Water Resources in Afghanistan

Researchers at the U.S. Geological Survey (USGS) Earth Resources Observation System (EROS) Data Center are using remote sensing data from NSIDC to monitor snow cover depletion for Afghanistan. This work supports the International Program Famine Early Warning System Network (FEWS NET) activities in the region.

FEWS NET is a U.S. Agency for International Development (USAID)-funded activity that collaborates with international, national, and regional partners to provide early warning and vulnerability information on food security issues. FEWS NET professionals in the U.S., Africa, Afghanistan, Central America, and the Caribbean work together to monitor remote sensing data and meteorological, crop, and rangeland conditions, as early indicators of potential threats to food security.

Approximately 80% of Afghanistan's annual wheat crop is dependent on irrigation, largely supplied through seasonal snowmelt. The ability to monitor both the extent of snow cover and the timing of depletion has proven invaluable in identifying areas that may experience reductions or surpluses in available irrigation water. Ground-based meteorological observations are often sparse or difficult to obtain in remote areas within Afghanistan. The key to measuring snow extent across a continuous spatial and temporal scale in these regions lies in satellite remote sensing.

USGS researchers calculated a short-term average of snow extent from three years (2001 through 2003) of 8-day snow extent data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard NASA's Terra satellite. The "MODIS/Terra Snow Cover 8-Day L3 Global 500m Grid" data set is available from NSIDC. Project staff pointed out that the improved spatial resolution of the MODIS snow extent products, combined with an algorithm that identifies snow by direct visible reflectance properties, helped them monitor cover depletion with greater accuracy. In addition, the 8-day product provides an adequate time step for minimizing cloud contamination while still providing a timely assessment of current conditions. In the case of Afghanistan, the relatively short temporal extent of the MODIS time series is still adequate for comparing near-term conditions with recent years that are still fresh in the minds of local people.

Using a basin delineation derived from the USGS HYDRO 1K Global Topographic Database, the researchers’ analysis concentrated on watersheds upstream of important irrigation areas. The MODIS 8-day data were used to identify areas above 2500 m within each basin, where historical average snow extent is approximately 100 percent in March.

The researchers construct standard snow depletion curves from the MODIS data that relate the percent of a basin or zone covered by snow to elapsed time during the snow melt season. These depletion curves provide an indication of the temporal and spatial extent of seasonal snow pack available for irrigation. MODIS snow data are also being used to refine the FEWS NET snow water equivalent model, and they are input to a snow extent and depth product that incorporates Air Force Weather Agency (AFWA) snow depths with MODIS-derived snow extent. The snow extent/depth product is mapped with a detailed road network to show areas that may be inaccessible due to snow; the map is distributed online as an Adobe PDF file.

Upper Kandahar Basin

Example of a snow accumulation/depletion curve for a southern (Kandahar) basin, illustrating the early depletion for the current year. Courtesy Michael Budde, USGS.

USGS researchers also compiled monthly averages of snow extent in Afghanistan at 25 km resolution from 1966 through 2001 from the "Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent Version 2" data set, available from NSIDC. This data set provides 36 years of snow extent data and monthly climatologies of average extent, prossbability of occurrence, and variance. Monthly averages of this time series are used as an historical marker of snow extent as well as snow accumulation and depletion.

The MODIS snow products will be used for continued monitoring of snow seasons in Afghanistan, but with the global scope of FEWS NET activities these same techniques may be applied in other regions where the availability of water for irrigation is critical to food security. Another application that will be further investigated is monitoring of permanent snowfield extents during the non-snow season. Visit the FEWS NET-Afghanistan site for more information and maps of snow extent.

Contact information: Michael E Budde (605) 594-2619; mbudde@usgs.gov.


New CD on Inuit Observations of Environmental Change

NSIDC and the Arctic System Science (ARCSS) Data Coordination Center have released a new multimedia, interactive CD, entitled When the Weather is Uggianaqtuq: Inuit Observations of Environmental Change. Uggianaqtuq (pronounced OOG-gi-a-nak-took) is a North Baffin Inuktitut word that means to behave unexpectedly, or in an unfamiliar way. From the perspective of many Inuit in the Arctic, the weather has been uggianaqtuq in recent years. In this CD, Inuit from two communities (Baker Lake and Clyde River) in Nunavut, Canada, share their observations and perspectives on recent environmental changes. Maps, text, photos, video and music are integrated to help illustrate the changes Inuit have observed in their environment and the impacts on their livelihoods.

The CD, authored by Shari Fox Gearheard, is available free of charge. To read more about the project or to order a copy of the CD, please visit the product web site.


NSIDC GLAS Altimetry elevation extractor Tool (NGAT)

This new software tool developed at NSIDC allows users to extract elevation and geoid data from ICESat/GLAS altimetry products (GLA06, 12, 13, 14, 15) in an easy-to-use ASCII-column output format. The NGAT runs under Interactive Data Language (IDL, 6.0 or greater) or the free IDL Virtual Machine (IDLVM). For access and information, please see NGAT tool page.


New and Improved ICESat/GLAS Altimetry Data

As of 07 April 2004, Release-13 data are available for GLA01 (Level-1A altimetry), and Release-14 data are available for GLA05 (Level-1B waveform corrections), GLA06 (Level-1B elevation), and GLA12-15 (Level-2 ice sheet, sea ice, land surface, and ocean altimetry) from 15 October 2003 through 18 November 2003 (19 November for GLA01).

These new versions of data have significantly improved calibration. They are available through the Earth Observing System (EOS) Data Gateway (EDG) and the NSIDC Data Pool. Learn more about details regarding these data, their improvements and limitations, reference orbital tracks, software tools, and ordering information.

These products have not been fully calibrated, and certain limitations in accuracy and definition remain. Improvements continue and will be reflected in future data releases. Users are asked to report their findings about data quality to NSIDC User Services, to be forwarded to the ICESat/GLAS Science Team, for information and comment before publication or reporting elsewhere.

New software tools for visualizing ICESat data and for extracting the data from binary into ASCII format are also available. These tools require Interactive Data Language (IDL) and run on all platforms. Users must have IDL 5.5 or higher


Snow Data Assimilation System (SNODAS) Products Now Available

In cooperation with the National Weather Service's National Operational Hydrologic Remote Sensing Center (NOHRSC), NSIDC is providing archive, access, and user support for eight selected SNODAS fields. SNODAS is a modeling and data assimilation system that provides the best possible estimates of snow cover and associated variables to support hydrologic modeling and analysis. The NOHRSC products available from NSIDC are gridded data sets for the continental United States at 1 km spatial resolution and 24-hour temporal resolution. This product is unique in terms of its utility for hydrological modeling.


New AMSR-E Products Available

In March and April 2004, NSIDC released five new AMSR-E gridded products:

Beginning 12 May 2004, NSIDC began distributing AMSR-E Level-2B rain and Level-3 rain, sea ice, and snow data with improved algorithms. All AMSR-E products are currently being processed back to June 2002, the start of the mission. Data are available from NSIDC via the Data Pool, Search 'N Order Web Interface (SNOWI), and EOS Data Gateway.


Other Recent Data Set Releases


User Forum

On 29 March 2004, NSIDC released an electronic bulletin board for users. The NSIDC User Board is a forum for users to exchange information and experiences working with NSIDC’s data. (The NSIDC User Board was removed in May of 2006).



Conference News

First Announcement: Workshop on EOS Snow and Ice Products

The First Workshop on EOS Snow and Ice Products will be held near Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, 16-17 November 2004. The intent of the workshop is to bring together current and potential users of EOS snow and ice standard products from the Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Microwave Scanning Radiometer - EOS (AMSR-E), Ice, Cloud and land Elevation Satellite (ICESat), Enhanced Thematic Mapper Plus (ETM+), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors. The themes of the workshop center on snow and ice products, including validation results; integration of EOS snow and ice products into models; production of climate data records, and improvements to data access and availability. Data producers will make presentations and NSIDC and the GSFC Distributed Active Archive Centers (DAACs) will demonstrate the acquisition and use of the products. All users of EOS data are invited to present posters on their snow- and ice-related results. There will be ample time during the workshop for discussions relative to the workshop themes. If interested, please contact Dorothy Hall at NASA/GSFC (Dorothy.K.Hall@nasa.gov), or Marilyn Kaminski at NSIDC (marilynk@nsidc.org)


WMO and IICWG Meetings

The Joint World Meteorological Organization Intergovernmental Oceanographic Commission (WMO-IOC) Technical Commission for Oceanography and Marine Meteorology (JCOMM) Expert Team on Sea Ice (ETSI) met on 15-17 April in Hamburg, Germany. This group of international sea ice experts is chaired by Vasily Smolyanitsky, Arctic and Antarctic Research Institute (AARI), St. Petersburg, Russia, and contributes to the work of the WMO Global Digital Sea Ice Data Bank (GDSIDB). The Steering Committee for the GDSIDB, which met concurrently with ETSI, is chaired by Ivan Frolov, Director, AARI, and Roger Barry, Director, NSIDC. The primary objective of these groups over the next year will be to update, in four languages, the WMO Sea Ice Nomenclature. Operational ice services use this dictionary of sea ice terms to find definitive descriptions of sea ice in all its manifestations.

A meeting of the International Ice Charting Working Group (IICWG) followed, hosted by the Bundesamt für Seeschiffahrt und Hydrographie (Federal Maritime and Hydrographic Agency of Germany). This group developed a new vector (shapefile) archive standard for operational charts, SIGRID-3, which, through the efforts of JCOMM is now a WMO standard format. Some of the work to be conducted in the intersessional period will include summarizing the socioeconomic benefits of ice services, articulating analysis and forecasting requirements in order to enhance connections with the research community, and developing a common schema for ice mapping system databases. Considerable attention is being paid to interfacing effectively with the international Group on Earth Observations (GEO), and the European Global Monitoring of Environment and Security (GMES) initiatives, as well as with Sea Ice Monitoring in the Polar Regions (ICEMON), a GMES project.


Symposium to Honor Roger Barry

“A Chronicle of Distinction: From the Arctic to the Andes,” the Roger Barry Symposium, will be held in Old Main at the University of Colorado, Boulder, on 8-10 August 2004. The symposium goal is to recognize the significance of Barry's extensive accomplishments and contributions to the science of climatology, as well as his teaching and mentoring. Former students and colleagues of Roger Barry are encouraged to attend and submit science papers focusing on current work that has evolved from past and/or present interactions with him. These will be included in the symposium materials or presented during the symposium, as time permits.

The symposium agenda, with tentative presentation schedules, is available online.




The Day After Tomorrow at NSIDC

In response to the Hollywood movie about abrupt climate change, NSIDC released a series of Q&A web pages to address issues presented in the film. The site includes NASA’s official response, as well as additional details with links to relevant information from NSIDC.


New GIS Product Web Page

Please visit NSIDC’s new GIS Data and Resources web page, providing direct access to a sample of products that are directly compatible with and easily imported into geographic information systems (GIS) software.