Temperature dependence of precipitating ice particle number concentrations of Arctic mixed-phase clouds observed by continuous ground-based measurements

• Main Authors: Koike, M., Saito, T., Tobo, Y., Ebell, K., Moteki, N., Ohata, S., Mori, T., Yoshida, A., Adachi, K., Baumgardner, D., Ong, C., Hashino, T.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Arctic; Svalbard
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018673

Arctic low level clouds are considered to play a significant role in the Arctic climate system. In this study, we examined a temperature dependence of precipitating ice particle number concentrations of Arctic mixed-phase clouds observed by continuous ground-based in situ measurements. Precipitating particles were measured using an optical disdrometer (MPS, DMT Inc.) at Mt. Zeppelin Observatory in Ny-Alesund (78.9N, 11.9E), Svalbard between years of 2016 and 2020. Based on ground-based cloud radar and lidar observations, we selected a single layer mixed-phase cloud whose cloud-top height was less than 2.5 km. For the ice nucleating particles number concentration (N INP ), we adopted typical number concentrations observed at Mt. Zeppelin. Because N INP depends on temperature, we used the value corresponding to the cloud-top temperature. As a result, number concentration fluxes of precipitation particles (F ice ) tended to increase with decreasing temperature below approximately -15°C and they agreed with F INP within one order of magnitude. On the other hand, at temperatures above -10°C, F ice was several orders of magnitude higher than F INP. In this paper, we discuss possible reasons for these temperature dependences of F ice.