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Precipitation at Dumont D'urville, Adélie Land, East Antarctica: The

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Precipitation at Dumont D'urville, Adélie Land, East Antarctica: The Earth Syst. Sci. Data, 10, 1605–1612, 2018 https://doi.org/10.5194/essd-10-1605-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Precipitation at Dumont d’Urville, Adélie Land, East Antarctica: the APRES3 field campaigns dataset Christophe Genthon1, Alexis Berne2, Jacopo Grazioli3, Claudio Durán Alarcón1, Christophe Praz2, and Brice Boudevillain1 1Univ. Grenoble Alpes, CNRS, IRD, Grenoble INP, IGE, 38000 Grenoble, France 2Environmental Remote Sensing Laboratory, Environmental Engineering Institute, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland 3Federal Office of Meteorology and Climatology, MeteoSwiss, Locarno-Monti, Switzerland Correspondence: Christophe Genthon ([email protected]) Received: 12 March 2018 – Discussion started: 26 April 2018 Revised: 23 July 2018 – Accepted: 6 August 2018 – Published: 6 September 2018 Abstract. Compared to the other continents and lands, Antarctica suffers from a severe shortage of in situ obser- vations of precipitation. APRES3 (Antarctic Precipitation, Remote Sensing from Surface and Space) is a program dedicated to improving the observation of Antarctic precipitation, both from the surface and from space, to assess climatologies and evaluate and ameliorate meteorological and climate models. A field measurement campaign was deployed at Dumont d’Urville station at the coast of Adélie Land in Antarctica, with an intensive observa- tion period from November 2015 to February 2016 using X-band and K-band radars, a snow gauge, snowflake cameras and a disdrometer, followed by continuous radar monitoring through 2016 and beyond. Among other results, the observations show that a significant fraction of precipitation sublimates in a dry surface katabatic layer before it reaches and accumulates at the surface, a result derived from profiling radar measurements. While the bulk of the data analyses and scientific results are published in specialized journals, this paper provides a compact description of the dataset now archived in the PANGAEA data repository (https://www.pangaea.de, https://doi.org/10.1594/PANGAEA.883562) and made open to the scientific community to further its exploita- tion for Antarctic meteorology and climate research purposes. 1 Introduction tion from in situ observations are left blank only over Antarc- tica. Satellites offer rising prospects to monitor remote, dif- The Antarctic ice sheet is a huge continental storage of wa- ficult and/or uninhabited regions, but even then Antarctica ter which, if altered through climate change, has the potential tends to be excluded from comprehensive and/or global stud- to significantly affect global sea level. While climate models ies (e.g. Funk et al., 2015). Only those studies that specif- consistently predict an increase in precipitation in the future ically focus on the polar regions and Antarctica have pre- in Antarctica (e.g. Palerme et al., 2016), most of which falls sented and discussed aspects of the Antarctic precipitation in the form of snow that will not melt and thus will accu- by satellite (Palerme et al., 2014, 2016, 2017; Behrangi et al., mulate further ice, observational data to raise confidence in 2016). However, ground-based observations are still lacking the current precipitation in the models are still in demand. to suitably calibrate and validate the satellite products. Antarctica is the poor cousin of global continental precip- The measurement of solid precipitation is notoriously dif- itation observation and climatology building efforts: citing ficult (Goodison et al., 1998; Nilu, 2013). Difficulties are ex- Schneider et al. (2014) of the Global Precipitation Climatol- acerbated in Antarctica because access and operations are lo- ogy Center (GPCC), “The GPCC refrains from providing a gistically difficult and environmental conditions are extreme. (precipitation) analysis over Antarctica” because of poor data Antarctica is the driest continent on Earth in terms of pre- coverage. The GPCC’s global maps of continental precipita- Published by Copernicus Publications. 1606 C. Genthon et al.: APRES3 field campaigns dataset cipitation: satellite data estimate the mean precipitation at fr, last access: 1 August 2018), starting in November 2015 171 mm yr−1 of water equivalent north of 81◦ S, the latitude until February 2016 for the intense observing period but still reached by the polar orbiting satellites (Palerme et al., 2014). ongoing for some observations, an unprecedentedly compre- Low precipitation is supported by net accumulation mea- hensive field campaign was launched at the French Dumont surements at the surface using glaciological methods (Eisen d’Urville Antarctic scientific station at the coast of Adélie et al., 2007) which yield equally low numbers (Arthern et Land. The objective was to measure and monitor precipita- al., 2006). On the high Antarctic plateau, the accumulation tion not only in terms of quantity, but also of falling snow par- is only a few cm yr−1 annually (e.g. Genthon et al., 2015). ticle characteristics and microphysics. The range of instru- Such a low precipitation rate would be very hard to moni- ments included a profiling K-band and a polarimetric scan- tor even in more hospitable environments. It is not possible ning X-band radar, a multi-angle snowflake camera (MASC), with conventional instruments in Antarctica. Satellite data an OTT Pluvio2 weighing gauge, and a Biral VPF-730 dis- and glaciological reconstructions, as well as models and me- drometer. A weather station reporting temperature, moisture teorological analyses, support a dry interior but indicate that and wind conditions near the instruments was also deployed. precipitation is much larger at the peripheries of the Antarc- Finally, a depolarization lidar was tentatively operated but tic ice sheet, yearly reaching several tens of centimetres, or had problems and is not further mentioned here. All instru- even metres, locally (Palerme et al. 2014). However, strong ments were removed at the end of January 2016 except the katabatic winds frequently blow at the peripheries, which K-band radar, which remained in operation throughout 2016 adversely affect the conventional precipitation measurement and beyond. Grazioli et al. (2017a) provide a comprehen- methods. Collecting instruments (bucket-style instruments sive description of the data and analysis techniques and dis- that capture and collect to measure snowfall, typically by cuss scientific outcomes. Further work is ongoing to address weighing or tipping bucket counts) actually undercatch or the calibration and validation of meteorological and climate overcatch because of air deflection and turbulence caused by models and of satellite remote sensing techniques with the the instruments themselves. In addition, they catch not only data (snowfall occurrences and rates, but also vertical pro- fresh falling snow, but also drifting/blowing snow which was files). Meanwhile, because this is a unique dataset, dissem- previously deposited at the surface, and then eroded and re- ination to the wider community for similar use with other mobilized by the strong winds. Non-catching instruments, in- models and remote sensing processing approaches or other cluding in situ (disdrometer) and remote (radar, lidar) sens- research purposes is considered timely. This paper provides ing instruments, offer interesting prospects. Radars are par- a compact description of the dataset and dissemination. ticularly attractive because they can profile through the air layers. They can sense both horizontally to expand the spa- 2 Dataset description tial significance of the measurement and vertically to scan the origin and fate of precipitation since condensation in the Grazioli et al. (2017a) provide ample information on the ob- atmospheric column, from the clouds (see Witze, 2016, for servation site, most instruments and methods. A summary an application in Antarctica) and above to the surface, and and complementary information are provided below. separate blowing snow in the lower layers from precipitation higher up. 2.1 Site description However, while radars are customarily used in other re- gions to monitor liquid precipitation (e.g. Krajewski and The main APRES3 (austral) summer field campaign took Smith, 2002; Fabry, 2015), and many campaigns have also place at French Antarctic scientific station Dumont d’Urville been conducted in high-latitude and high-altitude regions (DDU) in Adélie Land (66.6628◦ S, 140.0014◦ E; 41 m a.s.l. to study snowfall (e.g. Schneebeli et al., 2013; Grazioli et on average). The station is on Petrel Island located only al., 2015; Medina and Houze, 2015; Moisseev et al., 2015; ∼ 5 km off the continent and the ice sheet proper: the ob- Kneifel et al., 2015), experience is still limited in the Antarc- servations are thus representative of the very coast of the tic environment (Gorodetskaya et al., 2015). Because such Antarctic ice sheet. Because the station was operated for instruments do not collect and directly measure the mass of more than 60 years uninterruptedly, the means and statistics falling precipitation, but rather measure the fraction of an of meteorology and climate are documented (König-Langlo emitted radiation which is reflected back by the hydrome- et al., 1998; Grazioli et al., 2017a). A main meteorological teors, quantification in terms of precipitation involves both feature is the strong katabatic winds that frequently blow physically based (electromagnetic
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