Satellite remote sounding of atmospheric boundary layer temperature inversions over the subtropical eastern Pacific

We describe atmospheric temperature inversions and height-resolved water vapor fields over the wintertime subtropical northeastern Pacific Ocean in observations by the satellite-borne Atmospheric Infrared Sounder ( AIRS) experiment. A comparison with model analyses shows good agreement in temperature. Water vapor comparisons with operational radiosondes at four sites in California and Hawaii during December 2002-January 2003 have low biases in the 1000-700 and 700-500 hPa layers. Maps of inversion frequency, and, water vapor at 1000-700 and 700-500 hPa over the subtropical northeast Pacific during 1-16 January 2003 - when high pressure and clear conditions prevail - show inversions occurring at a local minimum in water vapor at 1000 - 700 hPa. Water vapor at 700 - 500 hPa has a broad minimum extending from Baja California to Hawaii, with inversions found on its eastern half. These observations illustrate the potential of the AIRS data for describing a climatology of temperature and water vapor in subtropical oceanic regions.