Abstract:
The Near Real-Time SSM/I EASE-Grid Daily Global Ice Concentration and
Snow Extent product (Near real-time Ice and Snow Extent, NISE)
provides daily, global near real-time maps of sea ice concentrations
and snow extent. The National Snow and Ice Data Center (NSIDC) creates
the NISE product using passive microwave data from the
... Defense
Meteorological Satellite Program (DMSP) F13 Special Sensor
Microwave/Imager (SSM/I). Sea ice concentration and snow extent maps
are provided in two 25 km azimuthal, equal-area projections: the
Southern Hemisphere 25 km low resolution (Sl) and Northern Hemisphere
25 km low resolution (Nl) Equal-Area Scalable Earth-Grids
(EASE-Grids). Data in Hierarchical Data Format - Earth Observing
System (HDF-EOS) format, and browse files in GIF and HDF formats, are
updated daily and are available via ftp and NSIDC's Data Pool for two
weeks after initial posting. Users can also order HDF-EOS data files
from 01 January 2000 through present via the Web-based Earth Observing
System (EOS) Data Gateway.
Sea ice concentrations are mapped using the NASA Team algorithm. Snow
extent is mapped separately using an algorithm developed for Scanning
Multichannel Microwave Radiometer (SMMR) data and modified for use
with SSM/I data (Chang, Foster, and Hall 1987; Armstrong and Brodzik
2001). The NISE product is updated daily using the best available data
from the past five days. NASA provided funding for the production of
this data set through the NSIDC Distributed Active Archive Center
(DAAC). NSIDC requests that prospective data users explain how the
data will be used and agree to contribute comments regarding the
usefulness, relevance, and accuracy of the data. Such feedback is
essential to ensure ongoing product improvement. Publication of
research results must appropriately acknowledge use of the NISE
product.
Data set information:
http://modis.gsfc.nasa.gov/data/dataprod/ 
