STUDY ON THE MAIN CLIMATE MODES OF SHANDONG PRECIPITATION AND THEIR RELATIONS WITH THE EAST ASIAN WESTERLY JET

YU Qun; WU Wei; ZHOU Fa-xiu; WANG Qi; LIU Yan

Abstract:

Summer precipitation patterns of Shandong Province are relatively independent with regard to the whole eastern China region. To study the rules and causes of precipitation variations, three main climate modes―on the annual, seasonal, and climatic intra-seasonal oscillation (CISO) scales―are extracted using a harmonic analysis method based on daily precipitation of Shandong during 1965-2009 and multi-year averaged pentad precipitation at 722 stations in China during 1971-2000. Among the three precipitation climate modes, the annual mode is closely related to the annual cycle of Earth-Atmosphere thermal system, which is characterized by the periodic dry and wet seasons. The seasonal mode reflects the monsoon effect on precipitation and the main flood season's contribution to annual precipitation variations. As an important climatic signal, the CISO mode is more evident during summer monsoon. The gradual modulations of the CISO mode, seasonal mode, and annual mode control the annual variation of precipitation. To study the relationship between precipitation climate modes and atmospheric circulations, an East Asian Westerly Jet Index (EAWJI) is defined in this paper. It is revealed that precipitation of Shandong is closely related to EAWJI in all climate modes. A wet or dry phase of each climate mode corresponds to a specific atmospheric circulation pattern. The phase of the annual mode is reverse to that of EAWJI. During the wet phase of the seasonal mode (weak phase of EAWJI), the atmospheric circulation in and around Shandong is characterized by upper-level divergence and low-level convergence. A reversed atmospheric circulation exists for the dry phase (strong phase for EAWJI). In the summer wet phase of CISO mode (strong phase of EAWJI), Shandong is controlled by upper-level divergence and low-level convergence. Again, the dry phase is corresponding to a reversed circulation structure. The methodology employed in this research, i.e. studying the precipitation climatic variations in terms of independent components of different temporal scales, provides a new approach for annual and seasonal precipitation prediction.

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YU Qun, WU Wei, ZHOU Fa-xiu, et al. STUDY ON THE MAIN CLIMATE MODES OF SHANDONG PRECIPITATION AND THEIR RELATIONS WITH THE EAST ASIAN WESTERLY JET [J]. Journal of Tropical Meteorology, 2012, 18(1): 72-80.

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STUDY ON THE MAIN CLIMATE MODES OF SHANDONG PRECIPITATION AND THEIR RELATIONS WITH THE EAST ASIAN WESTERLY JET

Laboratory of Ocean-Atmosphere Interaction and Climate OAC, Ocean University of China, Qingdao, 266100 China Shandong Meteorological Information Center, Ji'nan 250031 China

Shandong Meteorological Observatory, Ji'nan 250031 China

Laboratory of Ocean-Atmosphere Interaction and Climate OAC, Ocean University of China, Qingdao, 266100 China

Shandong Meteorological Service Center, Ji'nan 250031 China

Received Date: 2011-02-15

Rev Recd Date: 2011-12-07

Abstract: Summer precipitation patterns of Shandong Province are relatively independent with regard to the whole eastern China region. To study the rules and causes of precipitation variations, three main climate modes―on the annual, seasonal, and climatic intra-seasonal oscillation (CISO) scales―are extracted using a harmonic analysis method based on daily precipitation of Shandong during 1965-2009 and multi-year averaged pentad precipitation at 722 stations in China during 1971-2000. Among the three precipitation climate modes, the annual mode is closely related to the annual cycle of Earth-Atmosphere thermal system, which is characterized by the periodic dry and wet seasons. The seasonal mode reflects the monsoon effect on precipitation and the main flood season's contribution to annual precipitation variations. As an important climatic signal, the CISO mode is more evident during summer monsoon. The gradual modulations of the CISO mode, seasonal mode, and annual mode control the annual variation of precipitation. To study the relationship between precipitation climate modes and atmospheric circulations, an East Asian Westerly Jet Index (EAWJI) is defined in this paper. It is revealed that precipitation of Shandong is closely related to EAWJI in all climate modes. A wet or dry phase of each climate mode corresponds to a specific atmospheric circulation pattern. The phase of the annual mode is reverse to that of EAWJI. During the wet phase of the seasonal mode (weak phase of EAWJI), the atmospheric circulation in and around Shandong is characterized by upper-level divergence and low-level convergence. A reversed atmospheric circulation exists for the dry phase (strong phase for EAWJI). In the summer wet phase of CISO mode (strong phase of EAWJI), Shandong is controlled by upper-level divergence and low-level convergence. Again, the dry phase is corresponding to a reversed circulation structure. The methodology employed in this research, i.e. studying the precipitation climatic variations in terms of independent components of different temporal scales, provides a new approach for annual and seasonal precipitation prediction.

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Reference (20)

[1]	WANG Jian-guo. Climate in Shandong [M]. Beijing: China Meteorological Press, 2008: 20-21.
[2]	MURAKAMI T, CHEN L X, XIE A. Relationship amongseasonal cycles, low-frequency oscillations and transient disturbances as revealed from outgoing long-wave radiation data [J]. Mon. Wea. Rev., 1986, 114(8): 1456-1465.
[3]	LAU K M, YANG G J, SHEN S H. Seasonal and intraseasonal climatology of summer monsoon rainfall overEast Asia [J]. Mon. Wea. Rev., 1988, 116(1): 18-37.
[4]	WANG B, XU X. Northern hemisphere summer monsoonsingularities and climatological intraseasonal oscillation [J]. J.Climate, 1997, 10(5): 1071-1085.
[5]	YU Qun, HUANG Fei, WANG Qi, et al. IntraseasonalPrecipitation Patterns and Droughts-floods Coexistence and Abrupt Alternation in Shandong Province―Climatology [J].J.Trop. Meteor. , 2011, 27(5): 690-696.
[6]	CAI Er-cheng. Studies on Forerunner of Dryness/Wetnessin Summer in China During 1470-2006 [M]. Beijing: China Meteorological Press, 2009: 40-172.
[7]	ZHU Qian-gen, LIN Jin-rui, SHOU Shao-wen. Principles and Methods for Synoptic Meteorology [M]. Beijing: ChinaMeteorological Press, 1984: 194-198.
[8]	HUANG Jia-You, LI Huang. Spectral Analysis in Meteorology [M]. Beijing: China Meteorological Press, 1984:13-53.
[9]	PAN Shou-wen. Principles of Modern Climatology [M].Beijing: China Meteorological Press, 1994: 293-300.
[10]	LI Chong-yin, WANG Zuo-tai, LIN Shi-zhe, et al. The relationship between East Asian summer monsoon activity and northward jump of the upper westerly jet location[J].Chin. J.Atmos. Sci., 2004, 28(5): 641-658.
[11]	DONG Li-na, GUO Pin-wen, ZHANG Fu-ying.Relationship between variations of East Asian subtropical westerly jet from early summer to midsummer and withdrawalof Mei-Yu from Jianghuai region [J]. Trans. Atmos. Sci., 2010,33(1): 74-81.
[12]	KUANG Xue-yuan, ZHANG Yao-cun, LIU Jian.Relationship between subtropical upper-tropospheric westerlyjet and East Asian winter monsoon [J]. Plateau Meteor., 2008,27(4): 701-712.
[13]	YANG S , LAU K M , KIM K M. Variation of the EastAsian jet and Asian-Pacific-American winter climate anomalies[J]. J. Climate, 2002, 15(3): 306-325.
[14]	MAO Rui, GONG Dao-yi, FANG Qiao-min. Influences ofEast Asian jet on winter climate in China [J]. J. Appl. Meteor.Sci., 2007, 18(2): 137-145.
[15]	LI Chong-yin. Low-frequency Oscillation in theAtmosphere [M]. Beijing: China Meteorological Press, 1991:5-10.
[16]	LI Chong-yin, LONG Zhen-xia, MU Ming-quan.Atmospheric intraseasonal oscillation and its important effect[J]. Chin. J. Atmos. Sci., 2003, 27(4): 518-535.
[17]	YANG Hui, LI Chong-yin. The relation between atmospheric intraseasonal oscillation and summer severe floodand drought in the Changjiang-huaihe River basin [J]. Adv.Atmos. Sci., 2003. 20(4): 540-553.
[18]	JU Jian-hua，ZHAO Er-xu. Impacts of the low-frequency oscillation in East Asian summer monsoon on the drought andflooding in the middle and lower valley of the Yangtze River[J]. J. Trop. Meteor., 2005. 21(2): 163-171.
[19]	WANG Zun-ya, DING Yi-hui. Climatic characteristics ofrainy seasons in China [J]. Chin. J. Atmos. Sci., 2008, 32(1):1-13.
[20]	HUANG Fei, HUANG Shao-ni, ZHANG Xu. Study on theclimatological intraseasonal oscillation of Chinese rainfall [J]. J.Ocean Univ. China, 2008, 38(2): 173-177.

STUDY ON THE MAIN CLIMATE MODES OF SHANDONG PRECIPITATION AND THEIR RELATIONS WITH THE EAST ASIAN WESTERLY JET

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