Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.5194/acp-19-747-2019 |
A new interpretative framework for below-cloud effects on stable water isotopes in vapour and rain | |
Graf, Pascal1; Wernli, Heini1; Pfahl, Stephan1,2; Sodemann, Harald1,3,4 | |
2019-01-22 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS |
ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2019 |
卷号 | 19期号:2页码:747-765 |
文章类型 | Article |
语种 | 英语 |
国家 | Switzerland; Germany; Norway |
英文摘要 | Raindrops interact with water vapour in ambient air while sedimenting from the cloud base to the ground. They constantly exchange water molecules with the environment and, in sub-saturated air, they evaporate partially or entirely. The latter of these below-cloud processes is important for predicting the resulting surface rainfall amount. It also influences the boundary layer profiles of temperature and moisture through evaporative latent cooling and humidity changes. However, despite its importance, it is very difficult to quantify this process from observations. Stable water isotopes provide such information, as they are influenced by both rain evaporation and equilibration (i.e. the exchange of isotopes between raindrops and ambient air). This study elucidates this option by introducing a novel interpretative framework for stable water isotope measurements performed simultaneously at high temporal resolution in both near-surface vapour and rain. We refer to this viewing device as the Delta delta Delta d-diagram, which shows the isotopic composition (delta H-2, d-excess) of equilibrium vapour from precipitation samples relative to the ambient vapour. It is shown that this diagram facilitates the diagnosis of below-cloud processes and their effects on the isotopic composition of vapour and rain since equilibration and evaporation lead to different pathways in the two-dimensional phase space of the Delta delta Delta d-diagram, as investigated with a series of sensitivity experiments with an idealized below-cloud interaction model. The analysis of isotope measurements for a specific cold front in central Europe shows that below-cloud processes lead to distinct and temporally variable imprints on the isotope signal in surface rain. The influence of evaporation on this signal is particularly strong during periods with a weak precipitation rate. After the frontal passage, the near-surface atmospheric layer is characterized by higher relative humidity, which leads to weaker below-cloud evaporation. Additionally, a lower melting layer after the frontal passage reduces time for exchange between vapour and rain and leads to weaker equilibration. Measurements from four cold frontal events reveal a surprisingly similar slope of Delta d/Delta delta = -0.30 in the phase space, indicating a potentially characteristic signature of below-cloud processes for this type of rain event. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000456317400001 |
WOS关键词 | DEUTERIUM EXCESS ; PRECIPITATION ; O-18 ; FRACTIONATION ; EVAPORATION ; MODEL ; DELTA-H-2 |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/30395 |
专题 | 地球科学 |
作者单位 | 1.Swiss Fed Inst Technol, Inst Atmospher & Climate Sci, Zurich, Switzerland; 2.Free Univ Berlin, Inst Meteorol, Berlin, Germany; 3.Univ Bergen, Geophys Inst, Bergen, Norway; 4.Bjerknes Ctr Climate Res, Bergen, Norway |
推荐引用方式 GB/T 7714 | Graf, Pascal,Wernli, Heini,Pfahl, Stephan,et al. A new interpretative framework for below-cloud effects on stable water isotopes in vapour and rain[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2019,19(2):747-765. |
APA | Graf, Pascal,Wernli, Heini,Pfahl, Stephan,&Sodemann, Harald.(2019).A new interpretative framework for below-cloud effects on stable water isotopes in vapour and rain.ATMOSPHERIC CHEMISTRY AND PHYSICS,19(2),747-765. |
MLA | Graf, Pascal,et al."A new interpretative framework for below-cloud effects on stable water isotopes in vapour and rain".ATMOSPHERIC CHEMISTRY AND PHYSICS 19.2(2019):747-765. |
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