Influence of the freezing level on atmospheric rivers in High Mountain Asia: WRF case studies of orographic precipitation extremes.

Autor: Nash D; Center for Western Weather and Water Extremes, Scripps Institution of Oceanography, University of California, San Diego, CA 92093 USA., Carvalho LMV; Department of Geography and Earth Research Institute, University of California, Santa Barbara, CA 93106 USA., Rutz JJ; Center for Western Weather and Water Extremes, Scripps Institution of Oceanography, University of California, San Diego, CA 92093 USA., Jones C; Department of Geography and Earth Research Institute, University of California, Santa Barbara, CA 93106 USA.
Jazyk: angličtina
Zdroj: Climate dynamics [Clim Dyn] 2024; Vol. 62 (1), pp. 589-607. Date of Electronic Publication: 2023 Aug 28.
DOI: 10.1007/s00382-023-06929-x
Abstrakt: Atmospheric rivers (ARs) reach High Mountain Asia (HMA) about 10 days per month during the winter and spring, resulting in about 20 mm day -1 of precipitation. However, a few events may exceed 100 mm day -1 , providing most of the total winter precipitation and increasing the risk of precipitation-triggered landslides and flooding, particularly when the height of the height of the 0  ∘ C isotherm, or freezing level is above-average. This study shows that from 1979 to 2015, integrated water vapor transport (IVT) during ARs that reach Western HMA has increased 16% while the freezing level has increased up to 35 m. HMA ARs that have an above-average freezing level result in 10-40% less frozen precipitation compared to ARs with a below-average freezing level. To evaluate the importance of these trends in the characteristics of ARs, we investigate mesoscale processes leading to orographic precipitation using Advanced Weather Research and Forecasting (ARW-WRF) simulations at 6.7 km spatial resolution. We contrast two above- and below- average freezing level AR events with otherwise broadly similar characteristics and show that with a 50-600 m increase in freezing level, the above-average AR resulted in 10-70% less frozen precipitation than the below-average event. This study contributes to a better understanding of climate change-related impacts within HMA's hydrological cycle and the associated hazards to vulnerable communities living in the region.
Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest.
(© The Author(s) 2023.)
Databáze: MEDLINE
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