National Severe Storms Laboratory Seminar Series presents...
Developing visible-imagery cloudiness “climatologies” for diverse applications
Michael Douglas
NOAA/National Severe Storms Laboratory
Norman, OK
03 March 2009, 3:30 PM
National Weather Center, Room 1313
120 David L. Boren Blvd.
University of Oklahoma
Norman, OK
Directions to the NWC (.pdf, 60 kb)
Despite the wide use of visible-band satellite imagery for routine weather interpretation and forecasting, such imagery is much less used for quantitative research in meteorology. The difficulty of distinguishing clouds from snow or ice, in distinguishing thin or patchy clouds from the underlying land surface, the inability to determine cloud heights, and the lack of nighttime imagery can discourage quantitative work. Despite these problems, visible imagery usually has substantially better horizontal resolution (250m – 1 km pixel size) than the more widely-used infrared wavelengths.
We have been developing multi-year archives of visible imagery from both the GOES visible imager (~1 km pixels) and the NASA MODIS (~250m pixels) instruments to aid in interpreting climate over different parts of the tropics and subtropics. Despite the importance of this imagery for our specific research topics (not discussed in this talk) the greatest value of these cloud frequency “climatologies” may be in two very different applications. One is in the detection of systematic forecast errors in high-resolution numerical weather prediction models. The other application is in mapping and explaining of detailed variations in vegetation (and biodiversity) across the global tropics and subtropics at resolutions in excess of what can be mapped by land-based means. The latter application is actually considerably more urgent than the former, for reasons that will be mentioned.
Despite the limitations of our approach the results can be quite spectacular to meteorologists who may be accustomed to coarse-resolution climatologies and are likely to be even more dramatic to non-meteorologists.
The latter half of the talk will highlight different geographical regions around the world where the visible-imagery cloud climatologies can be particularly useful in interpreting/explaining the underlying vegetation patterns. Come and learn something about (bio)geography and climatology on very fine spatial scales!
This talk will be aimed towards a mixed audience (meteorologists, geographers, biologists-zoologists, botanists, ecologists etc). Raw imagery composites and some limited background material can be found at: http://www.nssl.noaa.gov/projects/pacs/web/MODIS/.