HR: 0800h
AN: B41A-0163    [Abstracts]
TI: Observations of orographic Cloud Base Heights from satellite and in-situ measurements at the Monteverde Cloud Mist Forest Reserve, Costa Rica
AU: * Asefi, S
EM: asefi@nsstc.uah.edu
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Zeng, J
EM: Jian.Zeng@noaa.gov
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Han, Q
EM: han@nsstc.uah.edu
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Welch, R M
EM: welch@nsstc.uah.edu
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Lawton, R O
EM: lawtonr@email.uah.edu
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Nair, U S
EM: nair@nsstc.uah.edu
AF: Department of Biological Sciences, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Ray, D
EM: dkray@purdue.edu
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: McCarty, W R
EM: Will.McCarty@msfc.nasa.gov
AF: Department of Atmospheric Science, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AU: Jedlovec, G
EM: gary.jedlovec@nasa.gov
AF: NASA Marshall Space Flight Center, National Space Science and Technology Center University of Alabama in Huntsville , Huntsville, AL 35805
AB: Tropical montane cloud mist forests are among the most biologically rich and diverse ecosystems, providing habitats for many of the world's endangered species. Survival of these habitats depends strongly on regular and frequent immersion in orographic clouds. At the Monteverde Cloud Mist Forest Reserve in Costa Rica, the bases of the clouds have shifted upslope, leading to anuran population crashes, an increase in the upper elevation of bird ranges on the Pacific slope, and longer dry season mist-free intervals. Satellite remote sensing techniques have been developed to determine the orographic cloud base heights; these are tested for the dry season month of March 2003 over the Monteverde cloud forests. The approach derives MODIS cloud top pressures and then converts them to cloud top heights using geopotential height profiles. The NCAR Land Use and Cloud Interaction Experiment (LUCIE), consisting of paired mobile radiosonde systems deployed in Costa Rica, provided the means for validating the retrievals. Results show that the four MODIS CO2 slicing channels do not provide sufficiently accurate cloud top height values, although some of the differences are due to a mismatch in the observational periods. In order to improve the results, two alternative approaches are examined. Simulated geopotential height profiles from the CSU Regional Atmospheric Modeling System (RAMS) initialized with soundings provided superior results. Another approach investigated the utility of multiple combinations of channels in the CO2 slicing technique using Atmospheric Infrared Sounder (AIRS) data for cloud height assignment. Using AIRS a more accurate determination of cloud top height is achieved. Cloud thicknesses are estimated using three different approaches: 1) constant liquid water content (CLWC); 2) an empirical relationship; and 3) an adiabatic model. The CLWC approach provided the most consistent results. Cloud base heights are computed from subtracting cloud thickness from cloud top height. Orographic cloud base heights derived from the combined MODIS/RAMS approach and AIRS were then compared with values observed at the study sites. Differences between the observed and remotely sensed values were on the order of 200-300m for MODIS/RAMS. The results suggest that it is possible to monitor global cloud mist forest cloud base heights using the combination of MODIS satellite imagery combined with AIRS and model simulations.
DE: 0466 Modeling
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: Fall Meeting 2005