Sea Surface Emissivity, Temperature and Atmospheric Measurements from the M-AERI During the ACAPEX Campaign

Description

The ARM Cloud Aerosol Precipitation Experiment (ACAPEX) took place in early 2015 to study atmospheric rivers in the Pacific Ocean and their impacts on the western United States. The second ARM mobile facility (AMF-2) was deployed on board the NOAA Ship Ronald H. Brown for this campaign, which included a new Marine Atmospheric Emitted Radiance Interferometer (M-AERI) to measure the atmospheric downwelling and reflected infrared radiance spectrum at the Earth's surface with high absolute accuracy. The M-AERI measures spectral infrared radiance between 520–3020 cm-1 (3.3–19 μm) at a resolution of 0.5 cm-1. The M-AERI can selectively view the atmospheric scene at zenith, and ocean/atmospheric scenes over a range of ±45° from the horizon. The AERI uses two high-emissivity blackbodies for radiometric calibration, which in conjunction with the instrument design and a suite of rigorous laboratory diagnostics, ensures the radiometric accuracy to be better than 1% (3σ) of the ambient radiance. The M-AERI radiance spectra can be used to retrieve profiles of temperature and water vapor in the troposphere, as well as measurements of trace gases, cloud properties, surface emissivity and ocean skin temperature. We present results on retrievals of ocean skin temperature, ocean emissivity properties as a function of view angle and wind speed, as well as comparisons with radiosondes and satellite observations.