Near-Surface Air Temperature Retrieval Derived from AMSU-A and Sea Surface Temperature Observations

Abstract

Abstract A 10-m air temperature (Ta) retrieval using Advanced Microwave Sounding Unit A (AMSU-A) and satellite-derived sea surface temperature (Ts) observations is presented. The multivariable linear regression retrieval uses AMSU-A brightness temperatures from the 52.8- and 53.6-GHz channels and satellite-derived daily sea surface temperatures to determine Ta. A regression error of 0.83°C using 841 matched satellite and ship observations demonstrates a high-quality fit of the satellite observations with in situ Ta. Validation of the retrieval using independent International Comprehensive Ocean–Atmosphere Dataset (ICOADS) ship and buoy observations results in a bias of −0.21°C and root-mean-square (RMS) differences of 1.55°C. A comparison with previous satellite-based Ta retrievals indicates less bias and significantly smaller RMS differences for the new retrieval. Regional biases inherent to previous retrievals are reduced in several oceanic regions using the new Ta retrieval. Satellite-derived Ts–Ta data were found to agree well with ICOADS buoy data and were significantly improved from previous retrievals.