Premium
A potential vorticity‐based index for the East Asian winter monsoon
Author(s) -
Huang Wenyu,
Wang Bin,
Wright Jonathon S.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd025053
Subject(s) - climatology , arctic oscillation , potential vorticity , siberian high , east asia , east asian monsoon , snow , monsoon , environmental science , intrusion , vorticity , geology , china , atmospheric sciences , meteorology , geography , northern hemisphere , geochemistry , vortex , archaeology
A novel dynamically based index that reflects the strength of the regional potential vorticity (PV) intrusion on the 300 K isentropic surface is proposed as a reliable measure of East Asian winter monsoon (EAWM) intensity. The index captures essential aspects of the EAWM, including its climatic influences on East Asia, its continuous weakening trend since the 1980s, and its close relationships with the Siberian high, Arctic Oscillation, and El Niño. The use of a potential vorticity framework enables the definition of a new metric called continuous PV intrusion duration (CPVID), which can be used to monitor and explain wintertime weather extremes like the extreme snowfall event that occurred in south China during January 2008. The CPVID of March is comparable to that of December, indicating that data from this month should be included in estimates of the strength of the EAWM.