Characteristic Features Observed in the East-Asian Cold Anomalies in January 2011

East Asia experienced extremely cold weather in January 2011, while the previousDecember and the following February had normal winter temperature. In this study NationalCenters for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data are used to investigate the characteristic features observed in the meteorologicalfields such as temperature, sea-level pressure, geopotential height, and wind duringthis winter period. In January the planetary-wave pattern is dominated by stationary-wave formin the mid-to-high latitude region, while transient waves are significant in the previous month.To understand the planetary-wave features quantitatively, harmonic analyses have been donefor the 500-hPa geopotential height field. In the climatological-mean geopotential heights thewave numbers 1, 2, and 3 are dominant during the whole winter. In January 2011 the waves ofnumber 1, 2, and 3 are dominant and stationary as in the climatological-mean field. In December2010 and February 2011, however, the waves of number 4, 5, and 6 play a major role andshow a transient pattern. In addition to the distinctive features in each month the planetarywavepatterns dependent on the latitude are also discussed.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000002478/2SEQ:2PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000002478ADJUST_YN:YEMP_ID:A004842DEPT_CD:3345CITE_RATE:0DEPT_NM:지구환경과학부SCOPUS_YN:NCONFIRM:

Relationship between the stratospheric quasi-biennial oscillation and the spring rainfall in the western North Pacific

©2013. American Geophysical Union. All Rights Reserved.The effects of the stratospheric quasi-biennial oscillation (QBO) on spring rainfall in the western North Pacific (WNP) are investigated using observational and reanalysis data for 1979-2012. After excluding the strong El Nino-Southern Oscillation events, composite analyses between opposite phases of the QBO are applied to the rainfall and related meteorological fields to show the differences in each QBO phase. In comparison with the easterly phase, during the westerly QBO, a midlatitude spring rainband extending from southeastern China to the east of the Japanese Islands is displaced southward, and thus, the spring rainfall over Korea and Japan exhibits a significant decrease. Such changes in the spring WNP rainfall are related to the location and intensity of the WNP subtropical high (WNPSH) and the East Asian jet (EAJ). The possible role of the QBO in modulating the WNPSH and the EAJ is discussed with regard to the strength of the Hadley circulation.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000002478/1SEQ:1PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000002478ADJUST_YN:YEMP_ID:A004842DEPT_CD:3345CITE_RATE:4.456DEPT_NM:지구환경과학부SCOPUS_YN:NCONFIRM:

Characteristic Features Observed in the East-Asian Cold Anomalies in January 2011

East Asia experienced extremely cold weather in January 2011, while the previousDecember and the following February had normal winter temperature. In this study NationalCenters for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data are used to investigate the characteristic features observed in the meteorologicalfields such as temperature, sea-level pressure, geopotential height, and wind duringthis winter period. In January the planetary-wave pattern is dominated by stationary-wave formin the mid-to-high latitude region, while transient waves are significant in the previous month. To understand the planetary-wave features quantitatively, harmonic analyses have been donefor the 500-hPa geopotential height field. In the climatological-mean geopotential heights thewave numbers 1, 2, and 3 are dominant during the whole winter. In January 2011 the waves ofnumber 1, 2, and 3 are dominant and stationary as in the climatological-mean field. In December2010 and February 2011, however, the waves of number 4, 5, and 6 play a major role andshow a transient pattern. In addition to the distinctive features in each month the planetarywavepatterns dependent on the latitude are also discussed.N