HR: 08:45h
AN: H51G-04    [Abstracts]
TI: Spatial Structure of Cloudiness Associated with the Mid-Summer Drought from MODIS and GOES Imagery
AU: * Douglas, M W
EM: Michael.Douglas@noaa.gov
AF: National Severe Storms Laboratory, 120 David L. Boren Blvd, Norman, OK 73072, United States
AU: Mejia, J
EM: John.Mejia@noaa.gov
AF: CIMMS/University of Oklahoma, 120 David L. Boren Blvd, Norman, OK 73072, United States
AU: Murillo, J
EM: Javier.Murillo@noaa.gov
AF: CIMMS/University of Oklahoma, 120 David L. Boren Blvd, Norman, OK 73072, United States
AU: Orozco, R
EM: Raquel.orozco@noaa.gov
AF: CIMMS/University of Oklahoma, 120 David L. Boren Blvd, Norman, OK 73072, United States
AB: The Mid-Summer Drought (MSD), a dry period within the overall rainy season, affects a region extending from southern Mexico, through parts of Central America, and into parts of northern South America. Studies based on rainfall data have shown that the MSD has a complex spatial structure. This talk will highlight some aspects of the local- and regional-scale aspects of the MSD using cloudiness data from both MODIS and GOES imagery. The MSD onset and demise dates for the past 6 years are identified from both North American Regional Reanalysis (NARR) winds and special pilot balloon observations made in two gaps in the Central American cordillera. By comparing the mean cloudiness prior to the MSD and during the MSD we show the spatial structure and intensity of the MSD from a cloud field perspective. A large decrease in cloudiness is seen on the Pacific side of the Isthmus of Tehuantepec during the onset of the MSD, while increasing cloudiness occurs to the north. There is an extremely sharp transition between the cloudiness regimes. We will show that this also agrees with detailed rainfall climatologies of the region. In general, the MODIS imagery, with 250m resolution, show the very close relationship between the underlying topography and the geographical variations of the MSD. GOES imagery, with coarser 10km resolution (but with the full diurnal cycle), has been used to depict the larger-scale aspects of the cloudiness changes associate with the onset and decay of the drought over different parts of Central America and the surrounding oceanic regions.
UR: http:www.nssl.noaa.gov/projects/pacs/web/MODIS/
DE: 1807 Climate impacts
DE: 1812 Drought
DE: 1840 Hydrometeorology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: 2007 Joint Assembly