Distinct Modes of the East Asian Winter Monsoon

Wu, Bingyi; Zhang, Renhe; D’Arrigo, Rosanne
August 2006
Monthly Weather Review;Aug2006, Vol. 134 Issue 8, p2165
Academic Journal
Two distinct modes of the East Asian winter monsoon (EAWM) have been identified, and they correspond to real and imaginary parts of the leading mode of the EAWM, respectively. Analyses of these modes used the National Centers for Environment Prediction (NCEP) and National Center for Atmospheric Research (NCAR) monthly mean reanalysis datasets for the period 1968–2003, as well as the Southern Oscillation index (SOI), North Atlantic Oscillation index, and eastern equatorial Pacific sea surface temperature (SST) data. Results were obtained by resolving a complex Hermite matrix derived from 850-hPa anomalous wind fields, and determining the resulting modes’ associations with several climate variables. The first distinct mode (M1) is characterized by an anomalous meridional wind pattern over East Asia and the western North Pacific. Mode M1 is closely related to several features of the atmospheric circulation, including the Siberian high, East Asian trough, East Asian upper-tropospheric jet, and local Hadley circulation over East Asia. Thus, M1 reflects the traditional EAWM pattern revealed in previous studies. The second distinct EAWM mode (M2), which was not identified previously, displays dominant zonal wind anomalies over the same area. Mode M2 exhibits a closer relation than M1 to sea level pressure anomalies over the northwestern Pacific southeast of Japan and with the SOI and equatorial eastern Pacific SST. Unlike M1, M2 does not show coherent relationships with the Siberian high, East Asian trough, and East Asian upper-tropospheric jet. Since atmospheric circulation anomalies relevant to M2 exhibit a quasi-barotropic structure, its existence cannot simply be attributed to differential land–sea heating. El Niño events tend to occur in the negative phase of M1 and the positive phase of M2, both corresponding to a weakened EAWM. The Arctic Oscillation does not appear to impact the EAWM on interannual time scales. Although the spatial patterns for the two modes are very different, the two distinct modes are complementary, with the leading EAWM mode being a linear combination of the two. The results herein therefore demonstrate that a single EAWM index may be inappropriate for investigating and predicting the EAWM.


Related Articles

  • Long-lead prediction of Indian summer monsoon rainfall from global SST evolution. Sahai, A. K.; Grimm, A. M.; Satyan, V.; Pant, G. B. // Climate Dynamics;May2003, Vol. 20 Issue 7/8, p855 

    A methodology is presented for making optimum use of the global sea surface temperature (SST) field for long lead prediction of the Indian summer monsoon rainfall (ISMR). To avoid the node phase of the biennial oscillation of El Niño Southern Oscillation (ENSO)-monsoon system and also to...

  • 1) PACIFIC. Mullan, A. B. // Bulletin of the American Meteorological Society;July 2014 Supplement, pS103 

    The article highlights the climatology of the intertropical convergence zones (ITCZ) in the Pacific in 2013. Topics discussed include the prevalence of the El Niño-Southern Oscillation (ENSO)-neutral conditions, the positions of the South Pacific convergence zones (SPCZ), and the skewed...

  • Extreme Wind Regime Responses to Climate Variability and Change in the Inner South Coast of British Columbia, Canada. Abeysirigunawardena, Dilumie S.; Gilleland, Eric; Bronaugh, David; Wong, Pat // Atmosphere -- Ocean (Canadian Meteorological & Oceanographic Soc;Mar2009, Vol. 47 Issue 1, p41 

    This study shows how information about climate variability can be valuable to the understanding of wind regime responses and improvement of wind forecasting skill. To this end we demonstrate the use and value of climate information in accurately determining extreme wind recurrences at three...

  • Extratropical Dry-Air Intrusions into the West African Monsoon Midtroposphere: An Important Factor for the Convective Activity over the Sahel. Roca, Rémy; Lafore, Jean-Philippe; Piriou, Catherine; Redelsperger, Jean-Luc // Journal of the Atmospheric Sciences;2/1/2005, Vol. 62 Issue 2, p390 

    This paper investigates the relationship between large-scale dynamics, water vapor, and organized convection over West Africa. Making use of a simplified condensation hypothesis, a back-trajectory model fed by NCEP-analyzed winds is used to reconstruct the midtropospheric humidity field over...

  • Southern hemisphere winter cold-air mesocyclones: climatic environments and associations with teleconnections. Claud, C.; Carleton, A. M.; Duchiron, B.; Terray, P. // Climate Dynamics;Aug2009, Vol. 33 Issue 2/3, p383 

    Cold-air mesocyclones remain a forecasting challenge in the southern hemisphere middle and higher latitudes, where conventional observations are lacking. One way to improve mesocyclone predictability is to determine their larger-scale circulation environments and associations with teleconnection...

  • Interactions among ENSO, the Monsoon, and Diurnal Cycle in Rainfall Variability over Java, Indonesia. Qian, Jian-Hua; Robertson, Andrew W.; Moron, Vincent // Journal of the Atmospheric Sciences;Nov2010, Vol. 67 Issue 11, p3509 

    Using a high-resolution regional climate model--the Abdus Salam International Centre for Theoretical Physics Regional Climate Model version 3 (RegCM3)--and station and satellite observations, the authors have studied the spatial heterogeneity of climate variability over Java Island, Indonesia....

  • The Indo-Australian monsoon and its relationship to ENSO and IOD in reanalysis data and the CMIP3/CMIP5 simulations. Jourdain, Nicolas C.; Gupta, Alexander Sen; Taschetto, Andréa S.; Ummenhofer, Caroline C.; Moise, Aurel F.; Ashok, Karumuri // Climate Dynamics;Dec2013, Vol. 41 Issue 11/12, p3073 

    A large spread exists in both Indian and Australian average monsoon rainfall and in their interannual variations diagnosed from various observational and reanalysis products. While the multi model mean monsoon rainfall from 59 models taking part in the Coupled Model Intercomparison Project...

  • ENSO modulation by mountain uplift. Kitoh, Akio // Climate Dynamics;Jul2007, Vol. 28 Issue 7/8, p781 

    How climate changes will modify the behavior of El Niño/Southern Oscillation (ENSO) is one of the important questions in future climate projections. An investigation under different climate forcing gives us a good insight on the mechanism of ENSO variability and its changes. In this paper,...

  • Variations of the SO Relationship with Summer and Winter Monsoon Rainfall over India: 1872-1993. Nageswara Rao, G. // Journal of Climate;12/1/99, Vol. 12 Issue 12, p3486 

    The lag correlations of the monthly and seasonal pressures at Darwin with the rainfall over India during summer (June-September) and winter (October-December) monsoons and their variations over 29 meteorological subdivisions in India are examined by using long time data for 122 yr (1872-1993). ...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics