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Dynamic and thermodynamic contributions to Northern China dryness in El Niño developing summer
Author(s) -
Liu Shujie,
Wen Na,
Li Laurent
Publication year - 2021
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6995
Subject(s) - dryness , climatology , advection , environmental science , water vapor , precipitation , energy budget , moisture , atmospheric sciences , meteorology , geology , physics , thermodynamics , medicine , surgery
In El Niño developing summer, Northern China shows reduced precipitation. The underlying mechanism is investigated through an analysis on the regional moisture and moist static energy budget. It is shown that the thermodynamic effect in relation to water vapour changes increases the regional wetness, but it is much smaller than the dynamic effect in relation to anomalies of atmospheric circulation. The anomalous vertical descent term is particularly pronounced. This anomalous vertical motion is mainly constrained by the horizontal advection of climatological moist enthalpy by anomalous wind, with a deficit of moist static energy in the region. A descent is then produced to compensate the energy lose and leads to dryness. Further investigation shows that an El Niño‐induced anomalous cyclone over Northeast Asia is the main ingredient in controlling the dynamic effect for both water vapour budget and moist static energy budget.