Open AccessEffect of changing tropical easterly jet, low level jet and quasi‐biennial oscillation phases on Indian summer monsoon
Author(s) -
Rai P.,
Dimri A. P.
Publication year - 2017
Publication title -
atmospheric science letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.951
H-Index - 45
ISSN - 1530-261X
DOI - 10.1002/asl.723
Subject(s) - climatology , monsoon , environmental science , homogeneous , quasi biennial oscillation , african easterly jet , atmospheric sciences , jet (fluid) , tropical cyclone , geology , tropical wave , troposphere , physics , thermodynamics
Using the National Center for Environmental Prediction and National Center for Atmospheric Research ( NCEP / NCAR ) reanalysis wind and homogeneous Indian summer monsoon ( ISM ) rainfall data during June, July, August and September ( JJAS ) for the period of 1953–2012, a long‐term trend has been extracted in the tropical easterly jet ( TEJ ) and lower level jet (Somali jet/ LLJ ) along with the rainfall trend over Indian region using empirical mode decomposition ( EMD ) technique. The zonal wind speed at 100 hPa shows an increasing trend, while a decreasing trend is observed at 850 hPa . The quasi‐biennial oscillation ( QBO ) phases, i.e. west and east phase, show a clear difference in wind anomalies at 100 and 850 hPa . A good (bad) monsoon year during the west (east) phase is confirmed on the basis of wind anomalies, velocity potential and divergent wind.