In:
Journal of Hydrometeorology, American Meteorological Society, Vol. 24, No. 9 ( 2023-09), p. 1479-1490
Abstract:
The transport of atmospheric water vapor plays a crucial role in the production of precipitation and the variation of precipitation isotopic composition ( δ 18 O p ). This study investigates three precipitation events with extremely depleted heavy isotopes in the summer of Adelaide, Australia. Using fundamental water vapor diagnosis and moisture calculation method, this research analyzes the impact of rainout degrees along moisture transport paths, atmospheric circulation patterns, water vapor sources, and moisture transport on the extreme depletion of precipitation isotopes in the study area. The purpose of this study is to reveal the direct cause of extremely depleted δ 18 O p at the hourly time scale. The results show the diversity and complexity of δ 18 O p variation in summer precipitation events in Adelaide. The rainout caused by local and upstream large precipitation may be the main reason for extremely low values of δ 18 O p . The phenomenon of subcloud secondary evaporation, which is driven by the interaction between relatively low humidity and high temperature at near-surface levels, plays a pivotal role in the entire precipitation process. This mechanism is particularly pronounced during the onset or cessation of precipitation events, thereby resulting in the observed enrichment of δ 18 O p values. The oxygen stable isotopic composition of water vapor ( δ 18 O a ) would usually become higher, when the air mass mixes with new moisture with relatively high δ 18 O a , suppressing the influence of the previous rainout.
Type of Medium:
Online Resource
ISSN:
1525-755X
,
1525-7541
DOI:
10.1175/JHM-D-22-0228.1
Language:
Unknown
Publisher:
American Meteorological Society
Publication Date:
2023
detail.hit.zdb_id:
2042176-X
