How important is tropospheric humidity for coastal rainfall in the tropics?

Abstract Climate models show considerable rainfall biases in coastal tropical areas, where approximately 33% of the overall rainfall received is associated with coastal land‐sea interaction. Building on an algorithm to objectively identify rainfall that is associated with land‐sea interaction we inv...

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Main Authors: Martin Bergemann, Christian Jakob
Format: Article
Language:English
Published: Wiley 2016-06-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL069255
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author Martin Bergemann
Christian Jakob
author_facet Martin Bergemann
Christian Jakob
author_sort Martin Bergemann
collection DOAJ
description Abstract Climate models show considerable rainfall biases in coastal tropical areas, where approximately 33% of the overall rainfall received is associated with coastal land‐sea interaction. Building on an algorithm to objectively identify rainfall that is associated with land‐sea interaction we investigate whether the relationship between rainfall in coastal regions and atmospheric humidity differs from that over the open ocean or over inland areas. We combine 3‐hourly satellite estimates of rainfall with humidity estimates from reanalyses and investigate if coastal rainfall reveals the well‐known relationship between area‐averaged precipitation and column‐integrated moisture. We find that rainfall that is associated with coastal land‐sea effects occurs under much drier midtropospheric conditions than that over the ocean and does not exhibit a pronounced critical value of humidity. In addition, the dependence of the amount of rainfall on midtropospheric moisture is significantly weaker when the rainfall is coastally influenced.
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spelling doaj-art-5148feca20744d46b4fc7270283d8fa72025-08-20T01:51:54ZengWileyGeophysical Research Letters0094-82761944-80072016-06-0143115860586810.1002/2016GL069255How important is tropospheric humidity for coastal rainfall in the tropics?Martin Bergemann0Christian Jakob1School of Earth, Atmosphere and Environment, Faculty of Science Monash University Melbourne Victoria AustraliaSchool of Earth, Atmosphere and Environment, Faculty of Science Monash University Melbourne Victoria AustraliaAbstract Climate models show considerable rainfall biases in coastal tropical areas, where approximately 33% of the overall rainfall received is associated with coastal land‐sea interaction. Building on an algorithm to objectively identify rainfall that is associated with land‐sea interaction we investigate whether the relationship between rainfall in coastal regions and atmospheric humidity differs from that over the open ocean or over inland areas. We combine 3‐hourly satellite estimates of rainfall with humidity estimates from reanalyses and investigate if coastal rainfall reveals the well‐known relationship between area‐averaged precipitation and column‐integrated moisture. We find that rainfall that is associated with coastal land‐sea effects occurs under much drier midtropospheric conditions than that over the ocean and does not exhibit a pronounced critical value of humidity. In addition, the dependence of the amount of rainfall on midtropospheric moisture is significantly weaker when the rainfall is coastally influenced.https://doi.org/10.1002/2016GL069255tropical rainfallhumiditytropical convection
spellingShingle Martin Bergemann
Christian Jakob
How important is tropospheric humidity for coastal rainfall in the tropics?
Geophysical Research Letters
tropical rainfall
humidity
tropical convection
title How important is tropospheric humidity for coastal rainfall in the tropics?
title_full How important is tropospheric humidity for coastal rainfall in the tropics?
title_fullStr How important is tropospheric humidity for coastal rainfall in the tropics?
title_full_unstemmed How important is tropospheric humidity for coastal rainfall in the tropics?
title_short How important is tropospheric humidity for coastal rainfall in the tropics?
title_sort how important is tropospheric humidity for coastal rainfall in the tropics
topic tropical rainfall
humidity
tropical convection
url https://doi.org/10.1002/2016GL069255
work_keys_str_mv AT martinbergemann howimportantistropospherichumidityforcoastalrainfallinthetropics
AT christianjakob howimportantistropospherichumidityforcoastalrainfallinthetropics