Extended Abstract (272K)6A.1
Estimation of Convective Planetary Boundary Layer Evolution and Land-Atmosphere Interactions from MODIS and AIRS
Joseph A. Santanello Jr., NASA/GSFC, Greenbelt, MD; and M. A. Friedl
Land-atmosphere interaction and coupling remain weak links in current observational and modeling approaches to understanding and predicting the Earth-Atmosphere system. The degree to which the land impacts the atmosphere (and vice-versa) is difficult to quantify given the disparate resolutions and complexity of land surface and atmospheric models. Remote sensing offers the ability to monitor PBL and land surface properties semi-continuously over time and space, and has the potential to provide valuable information on energy and water balances across a range of scales. While well-established satellites such as HIRS and GOES have been providing atmospheric profile data for decades, they are distinctly lacking in temporal and vertical resolution necessary to capture the diurnal evolution of the convective planetary boundary layer. In this study, atmospheric profiles retrieved from high-spectral resolution measurements made by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra and Aqua spacecraft and the Atmospheric Infrared Sounder (AIRS) aboard Aqua. The coverage of these sensors greatly improves upon the coarse network of synoptic radiosonde and intermittent satellite coverage available, and MODIS and AIRS are the first sensors that potentially allow for PBL structure and evolution to be in the context of its relationship and interactions with the land surface.
An evaluation of MODIS and AIRS retrievals is performed for 44 days at the ARM-SGP site using radiosonde data, focusing on how well PBL properties can be discerned from each sensor under a range of conditions. PBL structure and evolution from these profiles is assessed at the multiple overpass times of the MODIS and AIRS sensors, and previously developed methods to estimate PBL structure and infer surface conditions are applied using the remote sensing data. To circumvent biases found in the retrieval process, cloud-cleared radiances measured by AIRS in 2085 infrared channels are then examined in the context of PBL and surface property retrievals using statistical techniques. By exploiting strong absorption and window regions of the infrared spectrum, the response of relatively few AIRS channels can be used to describe land surface and PBL conditions on daily to seasonal timescales. Overall, this study highlights the current ability of remote sensing to estimate land-atmosphere interactions, as well as provides guidance for future sensor specification in order to improve our understanding of these processes on a global scale.
Session 6A, Land-Atmosphere Interactions 3
Thursday, 18 January 2007, 1:30 PM-4:30 PM, 209
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