|
Validation of AVHRR Cloud Retrievals with ARM NSA and SHEBA Data |
University of Alaska Fairbanks
Stevens Institute of Tech.
Stevens Institute of Tech.
Scripps Institution of Ocean.
University of Alaska Fairbanks
Retrieval of cloud optical depth and effective radius in the Arctic from satellite remote sensing data such as AVHRR is essential for studying the effects of clouds on the radiation budget on regional as well Arctic Basin wide scales. AVHRR data have been used in the past to retrieve cloud optical properties, but a comprehensive data set suitable for direct validation purposes has been lacking. Cloud discrimintation and retrieval in the Arctic is difficult due to (1) poor visible and thermal contrast between the cloud and the surface, (2) the multi-layered structure of the clouds, the (3) the presence of mixed-phase clouds, and (4) the abrupt change in surface conditions when the melt season starts. The ARM NSA and SHEBA programs provide a wealth of valuable data that are suitable for cloud retrieval validation in the Arctic. Here we use SHEBA data obtained during the April to August period to investigate the extent to which AVHRR data can be used to successfully retrieve cloud optical depth and effective radius.
