MODIS/Aqua CLD Mask Spect. Results 250m and 1km 5-Min L2 Narrow Swath Subset along CloudSat V2 (MAC35S0) at GES DISCEntry ID: GES_DISC_MAC35S0_v2
Abstract: This is the narrow-swath MODIS/Aqua subset along CloudSat field of view track.
The goal of the narrow-swath subset is to select and return MODIS data that are
within +-5 km across the CloudSat track. I.e. the resultant MODIS subset swath
is sought to be about 10 km cross-track. Geolocations in the original product,
however, are subsampled at 5-km, and thus the crosss-track width of the subset
... geolocations is 3 pixels. The subset Cloud Mask has 11 pixels across-track.
However, some of the Cloud Mask information is at bit level, thus allowing
storing actually 250-m information in seemingly 1-km pixels. This is achieved
by reserving 2 bytes (the last two out of six) of every 1-km pixel as 16
yes/no-cloud bits. Each one of these 16 bits flags a corresponding 250-m tile
inside the 1-km pixel. Their state is described in the local attributes to the
Cloud_Mask HDF data set, and accordingly must be interprated as 0=YES, 1=NO.
Thus the effective cross-track width, for these two bytes only, is 44 tiles of
Along-track, all MODIS pixels from the original product are preserved.
In the standard product, 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
"Two day repeat observations with a repeat orbit pattern every 16 days. The
locales where the ascending and descending modes are close or intersect can
have two observations per day."
(The shortname for this product is MAC35S0).
For more data set information:
A-Train Data Depot homepage: http://disc.sci.gsfc.nasa.gov/atdd/
MODIS Science Team homepage: http://modis.gsfc.nasa.gov/data/dataprod/
MODIS-Atmosphere homepage: http://modis-atmos.gsfc.nasa.gov/
Data Set Citation
Dataset Originator/Creator: GES DISC/MODIS
Dataset Title: MODIS/Aqua CLD Mask Spect. Results 250m and 1km 5-Min L2 Narrow Swath Subset along CloudSat
Dataset Release Date: October 2006
Dataset Release Place: Greenbelt, MD, USA
Dataset Publisher: Goddard Earth Science Data and Information Services Center (GES DISC)
Issue Identification: MAC35S0_2
Data Presentation Form: Digital Science DataOnline Resource: http://disc.sci.gsfc.nasa.gov/atdd/data_products.shtml
Start Date: 2000-03-01
Latitude Resolution: 1 km at nadir
Longitude Resolution: 1 km at nadir
Horizontal Resolution Range: 1 km - < 10 km or approximately .01 degree - < .09 degree
Temporal Resolution: Two day repeat observations with a repeat orbit pattern every 16 days.
Temporal Resolution Range: Daily - < Weekly
ISO Topic Category
Quality The following web site provides quality information on the MYD35_L2 product:
Access Constraints None
Use Constraints None
Data Set Progress
Distribution Media: Online (FTP)
Distribution Size: 0.253MB
Distribution Format: HDF
Role: DIF AUTHOR
Role: TECHNICAL CONTACT
Email: gsfc-help-disc at lists.nasa.gov
Goddard Earth Sciences Data and Information Services Center Code 610.2 NASA Goddard Space Flight Center
Province or State: MD
Postal Code: 20771
Creation and Review Dates
DIF Creation Date: 2006-09-22
Last DIF Revision Date: 2011-07-28