MISR
by Mary Forsythe — last modified May 23, 2013 07:27 PM
Contents
MISR and the NWP Impact Study
MISR Level 2 Cloud product AMVs have been reformatted into a simpler text format for time spans associated with the NWP Impact Study. These are:
- 2010/08/15 - 2010/09/30
- 2010/12/01 - 2011/01/15
- 2011/06/01 - 2012/08/01
This format provides one MISR AMV per line in per-orbit gzipped text files labeled by date and time. An example AMV line would be:
type sat day hms lat lon height spd dir qi VIS MISR 20100930 2351 81.02 -112.06 3123 0.9 138 0.72
This text format data excludes lower quality retrievals present in the Level 2 Cloud product.
This data is now only available upon request. To obtain it, please contact Kevin Mueller at kmueller@jpl.nasa.gov.
The MISR Instrument
MISR continues to fly aboard the polar orbiting EOS-Terra platform launched in 1999, with operation expected to continue til at least 2020. It consists of nine pushbroom cameras with one camera pointing toward the nadir (designated An), one bank of four cameras pointing in the forward direction (designated Af, Bf, Cf, and Df in order of increasing off-nadir angle), and one bank of four cameras pointing in the aftward direction (similarly designated Aa, Ba, Ca, and Da). Each camera observes spectral bands centered at 446, 558, 672, and 866 nm, yielding Earth ellipsoid projected images sampled at up to 275 resolution over a 360 km swath common to all cameras.
The Multi-angle Imaging SpectroRadiometer (MISR) project site is http://www-misr.jpl.nasa.gov
Instrument parameters are described at http://www-misr.jpl.nasa.gov/Mission/misrInstrument/
AMV Derivation
MISR Level 2 Cloud product algorithms retrieve both cloud height and horizontal motion from the apparent displacement due to parallax and movement of cloud features in visible channel (670nm) camera views during a single overpass. Retrievals are redundantly derived from forward (An-Bf-Df) and aft (An-Ba-Da) sets of camera images, then synthesized into a final height-resolved AMV.
AMV derived from the MISR instrument hold a unique set of strengths. These are:
- Integrated height retrieval insensitive to radiometric calibration or atmospheric temperature profile.
- AMVs capture motion over a 200 second interval at 17.6 km gridded resolution.
- Global coverage (excluding latitudes above 85 degrees)
- Observation record dating back to 2000 and projected to last until 2019.
The sampling and accuracy of the MISR Level 2 Cloud product is discussed in the MISR Level 2 Cloud Quality Statement
Documentation of the MISR Level 2 Cloud retrieval is provided by the Algorithm Theoretical Basis
Advice for research users
Real-time plots
MISR Level 2 Cloud data is not made available in real-time, but typically has a sensing-to-availability latency less than 24 hours. The MISR project expects to being offering wind data with roughly 3 hour latency by 2014.
NWP usage and impact
MISR data is not operationally assimilated. Preliminary (unpublished) studies of the new MISR wind product have shown significant positive impact.