Extended Abstract (1.9M)P1.28
Using A-train to establish the effects of Saharan Dust on the development and intensity of tropical cyclones
Thomas A. Kovacs, Eastern Michigan University, Ypsilanti, MI
A number of satellite data studies have shown that aerosols created from wind-blown dust off the Saharan Desert can impact tropical convection and particularly affect the development and intensity of tropical cyclones in the North Atlantic Ocean. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on-board the Aqua and Terra satellites provide cloud top temperature and aerosol optical depth to correlate the presence of aerosols with the intensity of convection within a tropical cyclone. This paper uses MODIS and new satellite data from the A-train constellation of satellites to further study these effects. These data will provide the first simultaneous measurements of the vertical distribution of cloud water and aerosol particles within a tropical cyclone. The Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar provides measurements of aerosol optical properties such as aerosol extinction and backscatter at wavelengths of 0.532 µm and 1.064 µm in a vertical column of the atmosphere The vertical profile of clouds within tropical storms is obtained from the cloud radar on-board the CloudSat satellite, which obtains vertical profiles 15 seconds after CALIPSO. The combination of these data will allow a direct relationship to be established between the presence of these aerosols and the horizontal and vertical distribution of the convective clouds that make up the tropical cyclone.
The initial study presented in this paper will show the ability of CALIPSO to capture an image of aerosol layers in the environment of tropical systems and the ability of CloudSat and MODIS to show convective cloud structure and structural changes within the tropical cyclone. On 2 August 2006, Tropical Storm Chris, seen as a circularly-symmetric mass of clouds in the MODIS visible image, approaches a thick aerosol layer seen to the west of the storm. The storm quickly dissipates within the next 24-48 hours. CloudSat cloud radar reflectivity plotted perpendicular to MODIS true-color visible reflection and CALIPSO aerosol backscatter plotted perpendicular to MODIS aerosol optical depth shows the extent of the interaction. The high resolution of cloud water and aerosol vertical cross-sections can provide input data into cloud scale and mesoscale models to further study and understand this interaction.
Poster Session 1, Recent Developments in Atmospheric Applications of Radar and lidar
Tuesday, 22 January 2008, 9:45 AM-11:00 AM, Exhibit Hall B
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