DOI: 10.1007/s00382-015-2884-7
Scopus记录号: 2-s2.0-84946811600
论文题名: Intra-event isotope and raindrop size data of tropical rain reveal effects concealed by event averaged data
作者: Managave S.R. ; Jani R.A. ; Narayana Rao T. ; Sunilkumar K. ; Satheeshkumar S. ; Ramesh R.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 47, 期: 2017-03-04 起始页码: 981
结束页码: 987
语种: 英语
英文关键词: Convective rainfall
; d-excess
; Disdrometer
; Meteoric water line
; Stable isotopes
英文摘要: Evaporation of rain is known to contribute water vapor, a potent greenhouse gas, to the atmosphere. Stable oxygen and hydrogen isotopic compositions (δ18O and, δD, respectively) of precipitation, usually measured/presented as values integrated over rain events or monthly mean values, are important tools for detecting evaporation effects. The slope ~8 of the linear relationship between such time-averaged values of δD and δ18O (called the meteoric water line) is widely accepted as a proof of condensation under isotopic equilibrium and absence of evaporation of rain during atmospheric fall. Here, through a simultaneous investigation of the isotopic and drop size distributions of seventeen rain events sampled on an intra-event scale at Gadanki (13.5°N, 79.2°E), southern India, we demonstrate that the evaporation effects, not evident in the time-averaged data, are significantly manifested in the sub-samples of individual rain events. We detect this through (1) slopes significantly less than 8 for the δD–δ18O relation on intra-event scale and (2) significant positive correlations between deuterium excess (d-excess = δD – 8*δ18O; lower values in rain indicate evaporation) and the mass-weighted mean diameter of the raindrops (Dm). An estimated ~44 % of rain is influenced by evaporation. This study also reveals a signature of isotopic equilibration of rain with the cloud base vapor, the processes important for modeling isotopic composition of precipitation. d-excess values of rain are modified by the post-condensation processes and the present approach offers a way to identify the d-excess values least affected by such processes. Isotope-enabled global circulation models could be improved by incorporating intra-event isotopic data and raindrop size dependent isotopic effects. © 2015, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53582
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Earth Sciences, Pondicherry University, Pondicherry, India; Geoscience Division, Physical Research Laboratory, Ahmedabad, India; National Atmospheric Research Laboratory, Gadanki, India
Recommended Citation:
Managave S.R.,Jani R.A.,Narayana Rao T.,et al. Intra-event isotope and raindrop size data of tropical rain reveal effects concealed by event averaged data[J]. Climate Dynamics,2016-01-01,47(2017-03-04)