Investigation of subcloud precipitation sublimation and evaporation with active remote sensing in Ny-Ålesund

Precipitation is an essential component of the Arctic climate system as part of the hydrological cycle, linking the atmosphere and cryosphere. Much of the Arctic precipitation sublimates or evaporates before it reaches the ground due to dry sub-cloud layers. The processes are thus controlling the input of the surface mass balance.

We use long-term atmospheric observations at Ny-Ålesund, Svalbard, with vertically-pointing cloud radars and backscattering lidars to identify and quantify atmospheric sublimation/evaporation. Radar observation-based sub-cloud precipitation profiles are studied by employing a virga detection tool, the so-called Virga-Sniffer (Kalesse-Los et al., 2023). The quantification of the sublimation/evaporation is based on sub-cloud vertical gradients of radar moments. First statistical results of precipitation thermodynamical phase, virga depth, and full sublimation/evaporation altitude above ground will be shown.

We will show investigations on wind direction dependence on virga statistics. Air masses advected from the Arctic Ocean are more humid and lead to more precipitation reaching the ground and thus less virga. Air masses advected over Ny-Ålesund from Easterly directions are often characterized by low-humidity subcloud layers leading to more evaporation/ sublimation and hence a higher fraction of virga. Furthermore, the occurrence frequency of virga and surface precipitation observed during different weather regimes such as cyclones, fronts, and atmospheric rivers is contrasted.

This work was supported by the DFG funded Transregio-project TRR 172 “Arctic Amplification (AC)³“.

Refernces:

Kalesse-Los, H., Kötsche, A., Foth, A., Röttenbacher, J., Vogl, T., and Witthuhn, J.: The Virga-Sniffer – a new tool to identify precipitation evaporation using ground-based remote-sensing observations, Atmos. Meas. Tech., 16, 1683–1704, https://doi.org/10.5194/amt-16-1683-2023, 2023.