Sep 11 2007
Aerosol Measurements with the Glory Satellite
The Glory satellite should be launched sometime in 2008. When it does, it should provide some interesting aerosol data from the Aerosol Polarimetry Sensor (APS) onboard.
|
From Mishchenko et.al (2007).
That’s nice, but let’s look at that APS requirements.
|
In particular, look at the GIFOV. The Geometric Instantaneous Field of View is the “size” of a pixel in the dataset. In general, the lower GIFOV the better. This instrument will have a GIFOV of 6.6 kilometers. As a comparison, Quickbird has a GIFOV of 60 centimeters in its panchromatic band. That 11000 times smaller than for Glory (4 orders of magnitude).
A 6.6 kilometer GIFOV covers an area of 3600 km2. For reference, Rhode Island has an area of 3144 km2. This means that one Glory pixel will be larger than a US state. The area of Rhode Island is about the same as the area of Los Angelos, California. The entire United States has an area of 9631420 km2. This means that Glory will only have 2675 pixels covering the entire US.
Aerosols are incredibly variable in both time and space. I think it’s clear from the 6.6 km GIFOV that Glory will be unable to distinguish spatial variabilities in the aerosol properties. Glory will be a part of the “A-Train“.
The satellites in the A-train are maintained in orbit to match the World Reference System 2 (WRS-2) reference grid. This reference system was developed to facilitate regular sampling patterns by remote sensors in the Landsat program. Each satellite completes 14.55 orbits per day with a separation of 24.7 degrees longitude between each successive orbit at the equator. The orbit tracks at the equator progresses westward 10.8 degrees on succeeding days, which over a 16-day period, produces a uniform WRS grid over the globe.
So the temporal resolution won’t be very good either. It’s still exciting that there will be a new sensor devoted specifically for aerosols and clouds.
Maybe I’m reading those spatial numbers wrong somehow. I don’t think I am, unless they’re using a different definition of GIFOV. It would have been nice if the GIFOV could be less than 1 km, which is the spatial resolution of the MODIS aerosol data product.
References:
Mishchenko, M.I., B. Cairns, G. Kopp, C.F. Schueler, B.A. Fafaul, J.E. Hansen, R.J. Hooker, T. Itchkawich, H.B. Maring, and L.D. Travis, 2007: Accurate Monitoring of Terrestrial Aerosols and Total Solar Irradiance: Introducing the Glory Mission. Bull. Amer. Meteor. Soc., 88, 677–691.
(No Ratings Yet)
Loading ...Related Posts:
To reduce spam, comments are automatically closed 30 days after the last comment. If you would like to comment on any closed thread, please use the contact form at the top of this page.
