Using the precipitation data at 124 stations of Yunnan and OLR data from NCAR/NCEP, the activity features and annual differences of Intra-Seasonal Oscillation (ISO) during main rainy season (June-August) in Yunan, and two paths along which tropic Indian ISO propagates to Yunnan and the impact of two Asian Summer Monsoon systems to ISO during main rainy season have been analyzed. The precipitation in main rainy season of Yunnan has prominent negative correlation with OLR averaged in Yunnan region. Summer monsoon ISO in Yunnan which is described as Low Frequency (LF) (30~60 d) OLR shows obvious intra-annual differences. In the stronger ISO years of main rainy season in Yunnan, LF convection propagates along two paths: One is strong westward propagation from tropic western Pacific ocean or southeastern China, which causing three times active LF convections during main rainy season of Yunnan; Another is propagation along southwest-northeast direction from tropic Indian ocean along the western bank of Bay of Bengal (BOB), which strengthens LF convection activities during main rainy season in Yunnan when it arrives in Yunnan. Otherwise, in the weak ISO years of main rainy season in Yunnan, just two times weak LF convections happen, which caused by two times weak zonal propagation of LF OLR from southern subtropical region: The first is westward propagation from subtropical western Pacific ocean, and the second is eastward propagation from Northern Arabian Sea. In the stronger ISO years, in developing process of tropic Indian LF convection, it propagates along southwest-northeast directions along the western bank of BOB, and excites the southwest Monsoon in BOB to propagates to Yunnan continually. On the another hand, it propagates eastward from BOB to South China Sea, and excites SCS Summer Monsoon (SCSSM) to propagate to subtropical eastern China and then turn to westward to Yunnan. When passing Yunnan, in northern BOB it meets LF convection that propagates northeastward from western bank of BOB, accomplishing a whole circle of relay propagation along zonal and meridional directions. Therefore, that is the excitation of ISO in tropic Indian to ISO in SCSSM and ISO in BOB southwest monsoon respectively along two paths, causes eastern Asian summer monsoon and southern Asian summer monsoon, these two Asian Monsoon systems impact together to ISO in main rainy season of Yunnan.
LI Ting
,
JU Jian-hua
. Impact of Intra-Seasonal Oscillation in Asian Summer Monsoon on Precipitation in Main Rainy Season of Yunnan I: Features and Propagation Processes of Intra-Seasonal Oscillation in Main Rainy Season of Yunnan[J]. Plateau Meteorology, 2013
, 32(3)
: 617
.
DOI: 10.7522/j.issn.1000-0534.2012.00060
[1]严华生, 鲁亚斌, 程建刚, 等.前期大气环流和海温变化对云南汛期雨量的影响[J]. 热带气象学报, 2005, 21(3): 248-256.
[2]严华生, 张青, 尤卫红.大气环流变化对云南5月雨量的影响及其预报[J]. 高原气象, 1994, 13(2): 217-222.
[3]琚建华, 李绚丽.云南初夏降水与前期大气环流的关系[J]. 高原气象, 1999, 18(1): 63-70.
[4]刘瑜, 马振锋, 陶云, 等. 云南2002年雨季偏旱的环流特征分析[J]. 高原气象, 2003, 22(增刊): 102-109.
[5]王宇. 云南气候变化概论[M]. 北京: 气象出版社, 1996: 118-133.
[6]段旭, 尤卫红, 郑建萌. 云南旱涝特征[J]. 高原气象, 2000, 19(1): 84-89.
[7]段旭, 陶云, 许美玲, 等. 西风带南支槽对云南天气的影响[J]. 高原气象, 2012, 31(4): 1059-1065.
[8]段长春, 朱勇, 尤卫红. 云南汛期旱涝特征及成因分析[J]. 高原气象, 2007, 26(2): 402-408.
[9]符传博, 吴涧, 丹利. 近50年云南省雨日及降水量的气候变化[J]. 高原气象, 2011, 30(4): 1027-1033.
[10]Madden R A, Julian P R. Detection of a 40~50 day oscillation in the zonal wind in the tropical Pacific [J]. J Atmos Sci, 1971, 28(5): 702-708.
[11]Madden R A, Julian P R. Description of global-scale circulation cells in the tropics with a 40~50-day period [J]. J Atmos Sci, 1972, 29(6): 1109-1123.
[12]Li C Y, Li G L. Evolution of intraseasonal oscillation over the tropical western Pacific/South China Sea and its effect to the summer precipitation in Southern China [J]. Adv Atmos Sci, 1997, 14(2): 246-254.
[13]李崇银. 大气低频振荡[M]. 北京: 气象出版社, 1991: 276.
[14]Madden R A, Julian P R. Observation of the 40~50 days tropical Oscillation A review[J]. Mon Wea Rev, 1994, 122: 814-837.
[15]Sperber K R. Propagation and the vertical structure of the Madden-Julian Oscillation[J]. Mon Wea Rev, 2003, 131: 3018-3037.
[16]李崇银, 龙振夏, 穆明权. 大气季节内振荡及其重要作用[J]. 大气科学, 2003, 27(4): 519-535.
[17]Yasunari T. A quasi-stationary appearance of 30 to 40 day period in the cloudiness fluctuations during the summer monsoon over India[J]. J Meteor Soc Japan, 1980, 58: 225-229.
[18]Yasunari T. Cloudiness fluctuations associated with the Northern Hemisphere summer monsoon[J]. J Meteor Soc Japan, 1979, 57(3): 227-242.
[19]Krishnamurti T N, Subrahmanyam D. 30~50-day mode at 850mb during MONEX[J]. J Atmos Sci, 1982, 39: 2088-2095.
[20]Wang Bin, Xu Xihua. Northern hemisphere summer monsoon singularities and climatological intraseasonal oscillation[J]. J Climate, 1997, 10: 1071-1085.
[21]张云瑾, 张成军. 云南夏季风振荡与降水的关系[J]. 热带气象学报, 1994, 10(3): 280-283.
[22]王恒康, 石昌惠. 云南夏季风振荡的初步分析[J]. 热带气象学报, 1987(2): 157-162.
[23]肖子牛, 温敏. 云南5月降水量与前期季节内振荡活动相互关系的分析研究[J]. 大气科学, 1999, 23(2): 177-183.
[24]琚建华, 叶乃青. 云南初夏雨量与前期热带OLR的联系[J]. 热带气象学报, 1999, 15(1): 76-80.
[25]解明恩, 鲁亚斌, 普贵明. 云南及其邻近地区OLR场的气候特征[J]. 高原气象, 1999, 18(2): 185-191.
[26]晏红明, 杞明辉, 肖子牛. 云南5月雨量与热带海温异常及亚洲季风变化的关系[J]. 应用气象学报, 2001, 12(3): 368-375.
[27]曹杰, 张小玲, 肖子牛. 云南5月强降水天气与亚洲季风变化的关系[J]. 云南大学学报(自然科学版), 2002, 24(5): 361-365.
[28]马峰波, 肖子牛, 李聪. 云南年降水与亚洲季风活动的关系[J]. 科技信息, 2009(2): 259-260.
[29]Liebmann B, Smith C A. Description of a complete (interpolated) outgoing long-wave radiation dataset[J]. Bull Amer Meteor Soc, 1996, 77: 1275-1277.
[30]Murakmi M. Large-scale aspects of deep convective activity over the GATE area[J]. Mon Wea Rev, 1979, 107: 994-1013.
