How does the spaceborne radar blind zone affect derived surface snowfall statistics in polar regions?

Maahn, Maximilian; Burgard, Clara; Crewell, Susanne; Gorodetskaya, Irina; Kneifel, Stefan; Lhermitte, Stef; Tricht, Kristof Van; Lipzig, Nicole Van

doi:10.1002/2014jd022079

Cited by 92 publications

(103 citation statements)

References 74 publications

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“…The influence of LSP on the vertical structure of precipitation raises the question of the interpretation of satellite-borne radar precipitation measurements over the Antarctica continent (23,24) that are currently the only model-free source of information able to cover the entire continent. These measurements must be discarded close to the surface because of ground clutter contamination of the radar signal (24), and the measurements at a certain height (1.2 km for CloudSat and around 0.8 km expected for EarthCare) above the surface are used as a proxy for near-ground precipitation.…”

Section: Discussionmentioning

confidence: 99%

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Katabatic winds diminish precipitation contribution to the Antarctic ice mass balance

Grazioli

Madeleine

Gallée

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

106

136

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Snowfall in Antarctica is a key term of the ice sheet mass budget that influences the sea level at global scale. Over the continental margins, persistent katabatic winds blow all year long and supply the lower troposphere with unsaturated air. We show that this dry air leads to significant low-level sublimation of snowfall. We found using unprecedented data collected over 1 year on the coast of Adélie Land and simulations from different atmospheric models that low-level sublimation accounts for a 17% reduction of total snowfall over the continent and up to 35% on the margins of East Antarctica, significantly affecting satellite-based estimations close to the ground. Our findings suggest that, as climate warming progresses, this process will be enhanced and will limit expected precipitation increases at the ground level.Antarctica | precipitation sublimation | katabatic wind P recipitation in Antarctica falls almost exclusively as snowfall (1). As the dominant input term, precipitation is a key component in the ice sheet mass balance, and changes to this balance can directly affect the sea level at the global scale (2-5). Over Antarctica, snowfall is still not well-quantified and less documented than elsewhere. This is partly because of the lack of measurements covering the processes from precipitation formation to ground deposition. After the recent momentum of atmospheric research in the polar regions (6) and thanks to the latest technological advances in the field of remote sensing, such measurements are starting to be regularly collected in various locations of the continent (7-9).The challenges affecting in situ snowfall observations are the extremely low temperatures and snowfall rates in the interior and the wind regime close to the coasts. Over the continental margins, persistent katabatic winds blow all year long (10, 11). They originate from the cold and dry inner continent and therefore, supply the lower troposphere with large masses of unsaturated air. Surface temperature inversion and the absence of orographic barriers allow katabatic winds to develop into some of the strongest, most persistent, and most directional near-surface winds on Earth (10-12). The effect of these winds on the transport and sublimation of snow after deposition at the surface has been studied, modeled, and quantified (13,14). This process turned out to be of primary importance for the ice sheet mass balance (3), in particular in the eastern part of the continent. The interaction of katabatic winds with snowfall, however, remains unknown, despite the importance of precipitation for the ice sheet mass balance.From November of 2015 to November of 2016, we conducted a field campaign dedicated to the monitoring of precipitation (9) at the Dumont d'Urville (DDU) station on the coast of East Antarctica (66.6628 S, 140.0014 E). We obtained unprecedented weather radar measurements of precipitation in Adélie Land by means of a scanning X-band polarimetric radar (deployed from December of 2015 to January of 2016) and a K-band vertically ...

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Section: Discussionmentioning

confidence: 99%

“…These measurements must be discarded close to the surface because of ground clutter contamination of the radar signal (24), and the measurements at a certain height (1.2 km for CloudSat and around 0.8 km expected for EarthCare) above the surface are used as a proxy for near-ground precipitation. The vertical structure in Fig.…”

Section: Discussionmentioning

confidence: 99%

Katabatic winds diminish precipitation contribution to the Antarctic ice mass balance

Grazioli

Madeleine

Gallée

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

106

136

View full text Add to dashboard Cite

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“…The processed data were col- lected with a temporal resolution of 1 min. The potential of the MRR to monitor polar regions has already been highlighted by the works of Maahn et al (2014) and Gorodetskaya et al (2015). The simplicity of its deployment and operation makes it an attractive tool for long-term measurements in places with complex logistics and with limited possibility of support, in the case of instrumental failures.…”

Section: Apres3 Instrumentsmentioning

confidence: 99%

Measurements of precipitation in Dumont d'Urville, Adélie Land, East Antarctica

et al. 2017

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“…A first estimate of snowfall rates over the AIS was derived from the Cloudsat satellite (Palerme et al, 2014). Its low overpass frequency, narrow swath width and ground clutter remains a limiting factor (Battaglia and Delanoë, 2013;Maahn et al, 2014;Casella et al, 2017). More locally, the operation of ground-based precipitation radars has proven to be an efficient way to detect snowfall over the AIS at several locations (Gorodetskaya et al, 2015;Souverijns et al, 2017;Grazioli et al, 2017a, b).…”

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confidence: 99%

How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

Souverijns¹,

Gossart²,

Gorodetskaya³

et al. 2017

Preprint

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Abstract. Local surface mass balance (SMB) measurements are crucial for understanding changes in the total mass of the Antarctic Ice Sheet, including its contribution to sea level rise. Despite continuous attempts to decipher mechanisms controlling the local SMB, a clear understanding of the separate components is still lacking, while snowfall measurements are almost absent. In this study, the different terms are quantified at the Princess Elisabeth (PE) station in Dronning Maud Land, East Antarctica. Furthermore, the relation between snowfall and accumulation at the surface is investigated. To achieve this, a 5 unique collocated set of remote sensing instrumentation (Micro Rain Radar, ceilometer, Automatic Weather Station, among others) was established operating for an unprecedented time period of 37 months. Snowfall originates mainly from moist and warm air advected from lower latitudes associated with cyclone activity. However, snowfall events are much more common than accumulation events. During 38 % of the snowfall cases observed, the freshly-fallen snow is ablated by the wind during the course of the event. Generally, snow storms of longer duration have a higher chance to attain for accumulation at the local scale, 10 while shorter events usually attain for ablation (on average 17 and 12 hours respectively). As such, SMB records cannot be considered a good proxy for snowfall at the local scale. Accumulation and ablation also occur during non-snowfall conditions. A large part of the accumulation at the station takes place when preceding snowfall events were occurring in upstream coastal areas. This fresh snow is easily picked up and transported in shallow drifting snow layers to more inland locations, even when wind speed is relatively low (< 7 ms −1 ). Ablation events are mainly related to katabatic winds originating from the Antarctic 15 plateau and the mountain ranges in the south. These dry winds are able to remove snow and lead to a decrease in the local SMB. This work highlights that, even though observations are local, the SMB is strongly influenced by synoptic upstream conditions.

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How does the spaceborne radar blind zone affect derived surface snowfall statistics in polar regions?

Cited by 92 publications

References 74 publications

Katabatic winds diminish precipitation contribution to the Antarctic ice mass balance

Katabatic winds diminish precipitation contribution to the Antarctic ice mass balance

Measurements of precipitation in Dumont d'Urville, Adélie Land, East Antarctica

How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

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