Measurements and Retrievals from a New 183-GHz Water Vapor Radiometer in the Arctic

A new G-band (183.31-GHz) vapor radiometer (GVR) developed and built by Prosensing Inc. (http://www.prosensing.com), was deployed in Barrow, Alaska, in April 2005. The radiometer is part of a suite of instruments maintained by the Atmospheric Radiation Measurement (ARM) program. The instrument measures brightness temperatures from four double sideband channels centered at plusmn1, plusmn3, plusmn7, and plusmn14 GHz from the 183.31-GHz water vapor line. Atmospheric emission in this spectral region is primarily due to water vapor, with some influence from liquid water. The GVR will remain in Barrow through the winter and will collect data for several months in a dry and cold environment, when its sensitivity is best. In this paper, data collected in November 2005, December 2005, and January 2006 are shown. Measurements are compared with simulations obtained using a radiative transfer model. We show that the measurements agree well with model simulations. Biases and standard deviations of the measurement-model differences are smaller than those reported in previous comparisons. Precipitable water vapor (PWV) and liquid water path (LWP) are retrieved with a non-linear physical algorithm and results are compared with those from the co-located dual-channel microwave radiometer (MWR) and radiosondes