The De-Icing Comparison Experiment (D-ICE): a study of broadband radiometric measurements under icing conditions in the Arctic Journal Article uri icon

Overview

abstract

  • Abstract. Surface-based measurements of broadband shortwave (solar); and longwave (infrared) radiative fluxes using thermopile radiometers are; made regularly around the globe for scientific and operational environmental; monitoring. The occurrence of ice on sensor windows in cold environments –; whether snow, rime, or frost – is a common problem that is difficult to; prevent as well as difficult to correct in post-processing. The Baseline; Surface Radiation Network (BSRN) community recognizes radiometer icing as a; major outstanding measurement uncertainty. Towards constraining this; uncertainty, the De-Icing Comparison Experiment (D-ICE) was carried out at; the NOAA Atmospheric Baseline Observatory in Utqiaġvik (formerly; Barrow), Alaska, from August 2017 to July 2018. The purpose of D-ICE was to; evaluate existing ventilation and heating technologies developed to mitigate; radiometer icing. D-ICE consisted of 20 pyranometers and 5 pyrgeometers; operating in various ventilator housings alongside operational systems that; are part of NOAA's Barrow BSRN station and the US Department of Energy; Atmospheric Radiation Measurement (ARM) program North Slope of Alaska and; Oliktok Point observatories. To detect icing, radiometers were monitored; continuously using cameras, with a total of more than 1 million images of; radiometer domes archived. Ventilator and ventilator–heater performance; overall was skillful with the average of the systems mitigating ice formation; 77 % (many >90 %) of the time during which icing conditions; were present. Ventilators without heating elements were also effective and; capable of providing heat through roughly equal contributions of waste; energy from the ventilator fan and adiabatic heating downstream of the fan.; This provided ∼0.6 ∘C of warming, enough to subsaturate the; air up to a relative humidity (with respect to ice) of ∼105 %.; Because the mitigation technologies performed well, a near complete record; of verified ice-free radiometric fluxes was assembled for the duration of; the campaign. This well-characterized data set is suitable for model; evaluation, in particular for the Year of Polar Prediction (YOPP) first; Special Observing Period (SOP1). We used the data set to calculate short-; and long-term biases in iced sensors, finding that biases can be up to +60 W m−2 (longwave) and −211 to +188 W m−2 (shortwave). However,; because of the frequency of icing, mitigation of ice by ventilators, cloud; conditions, and the timing of icing relative to available sunlight, the; biases in the monthly means were generally less than the aggregate; uncertainty attributed to other conventional sources in both the shortwave; and longwave.;

publication date

  • February 16, 2021

Date in CU Experts

  • June 8, 2021 9:28 AM

Full Author List

  • Cox CJ; Morris SM; Uttal T; Burgener R; Hall E; Kutchenreiter M; McComiskey A; Long CN; Thomas BD; Wendell J

author count

  • 10

Other Profiles

Electronic International Standard Serial Number (EISSN)

  • 1867-8548

Additional Document Info

start page

  • 1205

end page

  • 1224

volume

  • 14

issue

  • 2