| CHARACTERISTICS OF SEASONAL VARIATION OF RAINFALL OVER THE TIBETAN PLATEAU DURING SUMMER 1998 AND ITS IMPACT ON EAST ASIAN WEATHER |
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| 作者姓名： | 李薇 陈隆勋 |
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| 作者单位： | Chinese Academy of Meteorological Sciences Beijing 100081，Chinese Academy of Meteorological Sciences，Beijing 100081 |
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| 摘 要： | The seasonal variation of rainy season over the Tibetan Plateau in summer 1998 is analyzed byusing daily observational rainfall data for Lhasa from 1955 to 1996,and rainfall data at 70 stationsfrom January to August of 1998 over the Tibetan Plateau (TP) and adjacent regions,as well asTBB data from May to August of 1998.The onset date of rainy season for Lhasa is climatologically6 June.Among the analyzed years,the earliest onset date is 6 May,while the latest may delay to2 July.The obvious inter-decadal variation can be found in the series of onset date.The onset dateof summer 1998 over middle TP (onset date of Lhasa) is 24 June,which is relatively later than thenormal case.The onset for rainy season of 1998 started over southeast and northeast parts of TP and thenpropagated westward and northward.The convection over east and west parts of TP shows thatthere is a quasi 12-15 day oscillation.In June,the convection over middle and lower reaches ofYangtze River is formed by the westward propagation of convection over subtropical westernPacific.while in July.it is formed by the eastward propagation of convection over TP.Besides,it is also found that there exists good negative and obvious advance and lagcorrelation between the convection over the middle and western TP and that over the subtropicalwestern Pacific and southern China.Therefore it can be inferred that a feedback zonal circulationwith a quasi two-three week oscillation exists between the ascending region of TP and descendingregion of subtropical western Pacific,i.e.the convection over TP may affect the subtropical highover western Pacific and vice versa.
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CHARACTERISTICS OF SEASONAL VARIATION OF RAINFALL OVER THE TIBETAN PLATEAU DURING SUMMER 1998 AND ITS IMPACT ON EAST ASIAN WEATHER |
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| LI Wei CHEN Longxun Chinese Academy of Meteorological Sciences,Beijing.CHARACTERISTICS OF SEASONAL VARIATION OF RAINFALL OVER THE TIBETAN PLATEAU DURING SUMMER 1998 AND ITS IMPACT ON EAST ASIAN WEATHER[J].Acta Meteorologica Sinica,2001(3). |
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| Authors: | LI Wei CHEN Longxun Chinese Academy of Meteorological Sciences Beijing |
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| Institution: | LI Wei CHEN Longxun Chinese Academy of Meteorological Sciences,Beijing 100081 |
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| Abstract: | The seasonal variation of rainy season over the Tibetan Plateau in summer 1998 is analyzed by using daily observational rainfall data for Lhasa from 1955 to 1996,and rainfall data at 70 stations from January to August of 1998 over the Tibetan Plateau (TP) and adjacent regions,as well as TBB data from May to August of 1998.The onset date of rainy season for Lhasa is climatologically 6 June.Among the analyzed years,the earliest onset date is 6 May,while the latest may delay to 2 July.The obvious inter-decadal variation can be found in the series of onset date.The onset date of summer 1998 over middle TP (onset date of Lhasa) is 24 June,which is relatively later than the normal case. The onset for rainy season of 1998 started over southeast and northeast parts of TP and then propagated westward and northward.The convection over east and west parts of TP shows that there is a quasi 12-15 day oscillation.In June,the convection over middle and lower reaches of Yangtze River is formed by the westward propagation of convection over subtropical western Pacific.while in July.it is formed by the eastward propagation of convection over TP. Besides,it is also found that there exists good negative and obvious advance and lag correlation between the convection over the middle and western TP and that over the subtropical western Pacific and southern China.Therefore it can be inferred that a feedback zonal circulation with a quasi two-three week oscillation exists between the ascending region of TP and descending region of subtropical western Pacific,i.e.the convection over TP may affect the subtropical high over western Pacific and vice versa. |
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| Keywords: | ORS(onset of rainy season) monsoon Tibetan Plateau(TP) TBB quasi twothree week oscillation |
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