| Autor: |
Xu, Xin1 (AUTHOR), Chen, Xuelong1 (AUTHOR) x.chen@itpcas.ac.cn, Zhao, Xi2 (AUTHOR), Cao, Dianbin1 (AUTHOR), Liu, Yajing1 (AUTHOR), Li, Luhan1 (AUTHOR), Ma, Yaoming1,3,4,5,6,7 (AUTHOR) |
| Předmět: |
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| Zdroj: |
Journal of Geophysical Research. Atmospheres. 10/27/2023, Vol. 128 Issue 20, p1-19. 19p. |
| Abstrakt: |
Snowfall on the Tibetan Plateau (TP) is crucially important to the hydrological cycle and glacier acceleration over the TP and surroundings. Climate and weather models are challenged by biases and uncertainties in representing microphysical characteristics of snowfall over TP. In order to bridge the gaps in our understanding of microphysical characteristics of snowfall on the southeastern TP (SETP), an integrated and systematic measurement is conducted at the South‐East Tibetan Plateau Station during the two winters of 2022–2023. It is the first time to conduct a long‐term measurement of microphysical characteristics of snowfall on the SETP. The major objective of this campaign was to collect cloud microphysical properties including, fall velocity, aspect ratio, and particle size distribution (PSD). The results show that the particle number concentration is less than 103 mm−1·m−3, which is one to two orders of magnitude smaller than that reported in low‐altitudes in eastern China. The shape parameter μ is mainly in the range 0–4, and the slope parameter λ is mainly in the range 3–7 mm−1, exceeding the values for eastern China. In heavy snowfall processes (snowfall rate (SR) exceeding 2 mm/hr), the collision‐coalescence process between snowfall particles is enhanced, and the number concentration of small particles decreases with SR, whereas that of large particles increases. A negative correlation was observed between the aspect ratio and the diameter of snowfall particles. The microphysical characteristics of snowfall will be used to improve the microphysical scheme and evaluate the representation of precipitation in the climate model. Plain Language Summary: Snowfall on the southeastern Tibetan Plateau (SETP) affects the mass change of glaciers, the energy balance, and precipitation patterns on the TP and their surrounding areas. However, a large part of the forecast bias for snowfall in climate and weather models comes from the representation of the microphysical characteristics of snowfall. In order to close the knowledge gap, we conducted a long‐term observation experiment of the microphysical characteristics of snowfall on the SETP for the first time. The research purpose of this experiment is to investigate the microphysical characteristics of snowfall on the southeastern TP, such as fall velocity, aspect ratio, particle size distribution, and its vertical variation. The results show that the particle size distribution of snowfall particles on the southeastern TP is lower than that in the low‐altitudes. With the increase of snowfall rate, the collision‐coalescence process between snowfall particles is enhanced, the number of small particles decreases, and the number of large particles increases. Observations of the microphysical characteristics of snowfall will help improve snowfall estimates in climate weather models. Key Points: The first time to conduct a long‐term measurement of microphysical characteristics of snowfall on the southeastern Tibetan Plateau (SETP)Comparing the particle number concentration of snowfall on the SETP with that in low‐altitudes areasThe microphysical processes that dominate snowfall under different snowfall rates are different [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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