The 2004 North Slope of Alaska Arctic Winter Radiometric Experiment: Overview and Recent Results

Accurate measurements of water vapor in the Arctic winter, either in situ or remote, are difficult to achieve. These measurements are important to studies in infrared radiative transfer. To focus on measurements during cold temperatures (< 20oC) and low amounts of vapor (Precipitable Water Vapor, 5 mm), an Intensive Operating Period (IOP) was conducted at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program’s field site near Barrow, Alaska, during March 9 to April 9 2004. In this paper we give an overview of the experiment and show some highlights of the data analysis. Other results from this experiment are provided in [1, 2]. The major goal was to demonstrate that millimeter wavelength radiometers can substantially improve water vapor observations during the Arctic winter. Secondary goals included forward-model studies over a broad frequency range, demonstration of recently developed calibration techniques, the comparison of several types of in situ water vapor sensors, and the application of infrared imaging techniques. During this IOP, radiometers were deployed over a broad frequency range (22.235 to 400 GHz), including several channels near the strong water vapor absorption lines at 183.31 and 380.2 GHz. These radiometers were