The GSFC Distributed Active Archive Center (DAAC) distributes MODIS Airborne Simulator (MAS) Level-1B HDF Data. Through the GSFC DAAC, one may order:
- Specific Straight-Line Flight Tracks (SLFT's)
- Specific Missions (All the SLFT's for a particular Flight)
- Specific Field Experiments (All the SLFT's for a particular Campaign)
Specified sets of MAS Level-1B HDF (SLFT) files are copied onto 8200 or 8500 density, 8mm Exabyte Tape or Digital Linear Tape (DLT) and distributed to users in the scientific community.
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To order MAS Level-1B MAS data, contact:
hrubiak@daac.gsfc.nasa.gov
Goddard Distributed Active Archive Center
(301) 614-5165 (voice) |
The MAS Level-1B Data Granule = 1 Straight-Line Flight Track (SLFT):
The smallest unit (granule) of MAS data which is archived and can be ordered is a single straight-line flight track (or flight line) from a specific MAS mission. An individual straight-line flight track (or flight line) of MAS Level-1B data, containing calibrated and geolocated radiances for 50 spectral bands as well as a myriad of additional scientific data fields, are stored in a Hierarchical Data Format (HDF) file. A single MAS Level-1B HDF file containing all the data from 1 straight-line flight track is generally 100 megabyes to 1 gigabyte in size. More information on HDF, and the structure of MAS HDF files, can be obtained from the MAS Unpacking Page.
Each MAS Mission (or Flight) contains a number of SLFT's:
MAS missions are defined as a single flight (from take-off to landing) of the ER-2 aircraft (with the MAS instrument onboard and operating) and are always assigned a unique Flight Number. The number of flight lines within a single MAS mission varies, but is generally between 10 and 30. The volume of data varies, but is generally 5 to 10 gigabytes per flight. Dates and times noted for each MAS mission are always based on Greenwich Mean Time (GMT). It should be noted that MAS missions sometimes span 2 GMT days, its also possible that two MAS missions may have the same take-off date, therefore best way to identify a single MAS mission is by its unique Flight Number.
Each MAS Campaign (Field Experiment) contains a number of MAS Missions:
A collection of MAS missions are typically grouped into a single Field Experiment (or Campaign). Each Field Experiment has unique science objectives and typically lasts from several days to several weeks.
Reading Data:
Note that detailed instructions for reading MAS tapes are contained in the MAS Level-1B Data User's Guide. Software to unpack MAS HDF granules is offered on the MAS Unpacking Software page.
Back to: [Field Experiment Data]
[Accessibility]