| THE CONTRASTS BETWEEN STRONG AND WEAK MJO ACTIVITY OVER THE EQUATORIAL WESTERN PACIFIC IN
WINTER |
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| 作者姓名： | 陈 雄 李崇银 谭言科 郭文华 |
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| 摘 要： | This paper investigates the contrasts between strong and weak Madden-Julian
Oscillation (MJO) activity over the equatorial western Pacific during winter using the NCEP
reanalysis data. It is shown that the MJO over the equatorial western Pacific in winter shows
significant interannual and interdecadal variabilities. During the winters with strong MJO
activity, an anomalous cyclonic circulation lies east of the Philippines, strong anomalous
easterlies control the equatorial eastern Pacific, and anomalous westerlies extend from the
Indian Ocean to the western Pacific in the lower troposphere, which strengthens the
convergence and convection over the equatorial western Pacific. The moisture convergence in
the lower troposphere is also enhanced over the western Pacific, which is favorable to the
activity of MJO. Eastward propagation is a significant feature of the MJO, though there is
some westward propagation. The space-time spectral power and center period of the MJO are
higher during strong MJO activity winters. The anomalous activity of MJO is closely related to
the sea surface temperature (SST) and East Asian winter monsoon (EAWM). During strong MJO
activity winters, there are positive/negative anomalies at high/low latitudes in both sea
level pressure and 500 hPa geopotential height, and the temperature is lower over the central
part of the Chinese mainland, which indicates a strong EAWM. China experiences more rainfall
between the Yellow and Yangtze Rivers, but less rainfall south of the Yangtze River. The SSTA
is negative near the Taiwan Island due to the impact of strong EAWM and shows a La Ni?a
pattern anomaly over the eastern Pacific. During the weak MJO activity winters, the situation
is reversed.
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| 关 键 词： | weather and climate anomalous MJO activity EAWM ENSO anomalous temperature and precipitation in China |
| 修稿时间： | 2017/3/24 0:00:00 |
THE CONTRASTS BETWEEN STRONG AND WEAK MJO ACTIVITY OVER THE EQUATORIAL WESTERN PACIFIC IN
WINTER |
| |
| CHEN Xiong,LI Chong-yin,TAN Yan-ke and GUO Wen-hua.THE CONTRASTS BETWEEN STRONG AND WEAK MJO ACTIVITY OVER THE EQUATORIAL WESTERN PACIFIC IN
WINTER[J].Journal of Tropical Meteorology,2017,23(2):133-145. |
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| Authors: | CHEN Xiong LI Chong-yin TAN Yan-ke and GUO Wen-hua |
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| Institution: | College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing
211101 China |
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| Abstract: | This paper investigates the contrasts between strong and weak Madden-Julian Oscillation(MJO) activity over the equatorial western Pacific during winter using the NCEP reanalysis data. It is shown that the MJO over the equatorial western Pacific in winter shows significant interannual and interdecadal variabilities. During the winters with strong MJO activity, an anomalous cyclonic circulation lies east of the Philippines, strong anomalous easterlies control the equatorial eastern Pacific, and anomalous westerlies extend from the Indian Ocean to the western Pacific in the lower troposphere, which strengthens the convergence and convection over the equatorial western Pacific. The moisture convergence in the lower troposphere is also enhanced over the western Pacific, which is favorable to the activity of MJO. Eastward propagation is a significant feature of the MJO, though there is some westward propagation. The space-time spectral power and center period of the MJO are higher during strong MJO activity winters. The anomalous activity of MJO is closely related to the sea surface temperature(SST) and East Asian winter monsoon(EAWM).During strong MJO activity winters, there are positive/negative anomalies at high/low latitudes in both sea level pressure and 500 h Pa geopotential height, and the temperature is lower over the central part of the Chinese mainland, which indicates a strong EAWM. China experiences more rainfall between the Yellow and Yangtze Rivers, but less rainfall south of the Yangtze River. The SSTA is negative near the Taiwan Island due to the impact of strong EAWM and shows a La Nina pattern anomaly over the eastern Pacific. During the weak MJO activity winters, the situation is reversed. |
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| Keywords: | weather and climate anomalous MJO activity EAWM ENSO anomalous temperature and precipitation in China |
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