89th American Meteorological Society Annual Meeting

Monday, 12 January 2009
Enhanced satellite cloud products for climate studies
Hall 5 (Phoenix Convention Center)
Tom Greenwald, CIMSS/Univ. of Wisconsin, Madison, WI; and R. Bennartz
Satellite-based climate studies of clouds rarely take advantage of the complimentary information provided by microwave and solar/infrared observations. The few studies that have used these observations often combine them in a non-optimal way using coarse time/space criteria. The down side of this approach is that the cloud conditions occurring within the microwave instrument's relatively wide field-of-view (FOV) cannot be adequately characterized, which can greatly influence the interpretation of microwave-derived cloud products and their direct comparison with similar solar/infrared products.

To address this problem, new enhanced products are being developed that combine nearly instantaneous microwave-derived liquid water path (LWP) products with solar/infrared cloud products using detailed collocation methods. As a demonstration of the approach, Level 2 products from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and the MODerate resolution Imaging Spectroradiometer (MODIS) measurements on Aqua are combined. The AMSR-E data used are the Version 2 Level 2B ocean swath products that include the LWP, total precipitable water, surface wind speed, and sea surface temperature. The MODIS cloud products (MYD06 Collection 5) include the cloud mask, visible optical depth, particle effective radius, cloud phase, detection of multi-level clouds, and cloud top pressure and temperature. The data collocation method used is a fast algorithm that predicts the scan line and element number for the MODIS pixel closest to the centroid of the AMSR-E FOV. Once this pixel is known, all MODIS data that fall within the AMSR-E footprint can be easily determined. The new Level 2 collocated products will be full-resolution swath data with various cloud statistics provided within each AMSR-E FOV. Additional products, which are not part of the MYD06 or ocean swath products, will also be included. These new products are MODIS-derived geometric thickness and droplet number concentration for water clouds and flags for precipitation occurring within the AMSR-E FOV. Level 3 products will also be produced, consisting of monthly 0.5-degree gridded datasets for both cloud-cleared and cloudy sky data. Cloud-cleared microwave-derived LWP products are included because of their usefulness in quantifying minimum errors in microwave-derived LWP products when clouds are present. Results will be presented at the conference.

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