Abstract:
MODIS was launched aboard the Aqua satellite on May 4, 2002 (1:30 pm
equator crossing time) as part of NASA's Earth Observing System (EOS)
mission. MODIS with its 2330 km viewing swath width provides almost
daily global coverage. It acquires data in 36 high spectral resolution
bands between 0.415 to
... 14.235 micron with spatial resolutions of
250m(2 bands), 500m(5 bands), and 1000m (29 bands). MODIS sensor
counts, calibrated radiances, geolocation products and all derived
geophysical atmospheric and ocean products are archived at NASA
Goddard DAAC and has been made available to public since April 2000.
The MODIS level-2 cloud mask product is a global product generated for
both daytime & nighttime conditions at 1-km spatial resolution (at
nadir) and for daytime at 250-m resolution. The algorithm employs a
series of visible and infrared threshold and consistency tests to
specify confidence levels that an unobstructed view of the Earth's
surface is observed. An indication of shadows affecting the scene
is also provided. The 250-m cloud mask flags are based on the
visible channel data only. Radiometrically accurate radiances are
required, so holes in the cloud mask will appear wherever the input
radiances are incomplete or of poor quality. The shortname for
this Level-2 MODIS cloud mask product is MYD35_L2 and the principal
investigator for this product is MODIS scientist Dr. Paul Menzel (
paulm@ssec.wisc.edu).
MYD35_L2 product files are stored in Hierarchical Data Format
(HDF-EOS). Each of the 9 gridded parameters is stored as a Scientific
Data Set (SDS) within the HDF-EOS file. The Cloud Mask and Quality
Assurance SDS's are stored at 1 kilometer pixel resolution. All other
SDS's (those relating to time, geolocation, and viewing geometry) are
stored at 5 kilometer pixel resolution. Each file is roughly 47.5 MB
in size, and the total data volume is approximately 13.7 GB/day. For
browsing and extracting data from these files, some software are made
available at the site.
MYD35_L2 Data Group & Parameters
Spatial & Temporal Resolution:
Latitude & Longitude
Scan start time
Solar and Sensor Viewing Geometry:
Solar zenith & Solar azimuth angle
Sensor zenith & Sensor azimuth angle
Science Parameters
Cloud Mask (1km)
Cloud Mask (250 m)
Quality Assurance Parameters:
Quality Assurance Flags (1km)
For more information about the MYD35_L2 product, visit the
MODIS-Atmosphere site at:
http://modis-atmos.gsfc.nasa.gov/MOD35_L2/ 
