Atmospheric Measurement Techniques | 2019
Calibration of the 2007–2017 record of Atmospheric Radiation Measurements cloud radar observations using CloudSat
Abstract
Abstract. The U.S. Department of Energy (DOE) Atmospheric Radiation\nMeasurements (ARM) facility has been at the forefront of millimeter-wavelength radar development and operations since the late 1990s. The\noperational performance of the ARM cloud radar network is very high;\nhowever, the calibration of the historical record is not well established.\nHere, a well-characterized spaceborne 94\u2009GHz cloud profiling radar\n(CloudSat) is used to characterize the calibration of the ARM cloud radars.\nThe calibration extends from 2007 to 2017 and includes both fixed and mobile\ndeployments. Collectively, over 43 years of ARM profiling cloud radar\nobservations are compared to CloudSat and the calibration offsets are\nreported as a function of time using a sliding window of 6 months. The study\nalso provides the calibration offsets for each operating mode of the ARM\ncloud radars. Overall, significant calibration offsets are found that exceed\nthe uncertainty of the technique (1–2\u2009dB). The findings of this study are\ncritical to past, ongoing, and planned studies of cloud and precipitation\nand should assist the DOE ARM to build a legacy decadal ground-based cloud\nradar dataset for global climate model validation.