Cloud and precipitation properties from ground-based remote-sensing instruments in East Antarctica

Abstract

Abstract. A new comprehensive cloud–precipitation–meteorological observatory has been established at Princess Elisabeth base, located in the escarpment zone of Dronning Maud Land (DML), East Antarctica. The observatory consists of a set of ground-based remote-sensing instruments (ceilometer, infrared pyrometer and vertically profiling precipitation radar) combined with automatic weather station measurements of near-surface meteorology, radiative fluxes, and snow height. In this paper, the observatory is presented and the potential for studying the evolution of clouds and precipitating systems is illustrated by case studies. It is shown that the synergetic use of the set of instruments allows for distinguishing ice, liquid-containing clouds and precipitating clouds, including some information on their vertical extent. In addition, wind-driven blowing snow events can be distinguished from deeper precipitating systems. Cloud properties largely affect the surface radiative fluxes, with liquid-containing clouds dominating the radiative impact. A statistical analysis of all measurements (in total 14 months mainly during summer–beginning of winter) indicates that these liquid-containing clouds occur during as much as 20% of the cloudy periods. The cloud occurrence shows a strong bimodal distribution with clear-sky conditions 51% of the time and complete overcast conditions 35% of the time. Snowfall occurred during 17% of the cloudy periods with a predominance of light precipitation and only rare events with snowfall >1 mm h−1 water equivalent (w.e.). Three of such intense snowfall events occurred during 2011 contributing to anomalously large annual surface mass balance (SMB). Large accumulation events (>10 mm w.e. day−1) during the radar-measurement period of 26 months were always associated with snowfall, but at the same time other snowfall events did not always lead to accumulation. The multiyear deployment of a precipitation radar in Antarctica allows for assessing the contribution of the snowfall to the local SMB and comparing it to the other SMB components. During 2012, snowfall rate was 110 ± 20 mm w.e. yr−1, from which surface and drifting snow sublimation removed together 23%. Given the measured yearly SMB of 52 ± 3 mm w.e., the residual term of 33 ± 21 mm w.e. yr−1 was attributed to the wind-driven snow erosion. In general, this promising set of robust instrumentation allows for improved insight into cloud and precipitation processes in Antarctica and can be easily deployed at other Antarctic stations.

Evaluation of current and projected Antarctic precipitation in CMIP5 models

“…Furthermore, field observations are sparse and rare in Antarctica, which prevents a robust evaluation of remote sensing retrievals. For instance, determining the contribution of shallow precipitation to total precipitation remains an issue, and in-situ observations, as those presented by Gorodetskaya et al (2015), should provide new informations for assessing the contribution of shallow precipitation. New in-situ observations of precipitation are needed in Antarctica to evaluate and improve remote sensing retrievals, and thus for more robust evaluation of climate model simulations.…”

Improving satellite-retrieved surface radiative fluxes in polar regions using a smart sampling approach

“…van den Broeke, 2004;Sedlar et al, 2011;Gorodetskaya et al, 2015) and evaluation purposes of climate models (e.g. Gallée and Gorodetskaya, 2010;King et al, 2015;English et al, 2015).…”

“…For developing the methodology and evaluation purposes, retrieved radiative fluxes from CloudSat and CALIPSO are compared to ground-based fluxes measured by AWSs, including five stations from the Baseline Surface Radiation Network (BSRN) (Ohmura et al, 1998) and an AWS at the Princess Elisabeth (PE) station in Antarctica (Gorodetskaya et al, 2013(Gorodetskaya et al, , 2015 (Fig. 2).…”

A New Regional Climate Model for POLAR‐CORDEX: Evaluation of a 30‐Year Hindcast with COSMO‐CLM2 Over Antarctica

“…In austral winter, however, there is a structural underestimation of the longwave incoming radiation in the model simulation, which equals on average 20 W/m 2 . Based on cloud (phase) observations at the Princess Elisabeth station (71°57 ′ S, 23°21 ′ E; Figure ), located in Dronning Maud Land, it is hypothesized that this could be attributed to an underestimation in the amount of (liquid‐containing) clouds over the station during austral winter (Gorodetskaya et al, ). Clouds have a large radiative effect on the ice sheet and significantly contribute to the amount of incoming longwave radiation (Van Tricht et al, ).…”

“…During the austral winter of 2015, ceilometer observations are available at the Princess Elisabeth station. This instrument can detect cloud base heights and is able to make a distinction between liquid and ice clouds using the approach of Gorodetskaya et al () and Van Tricht et al (). In austral winter 2015, the ceilometer observed overcast conditions 77% of the time.…”