1971—2015年辽宁省海岸带大风时空分布特征及成因分析
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摘要
利用1971—2015年辽宁省海岸带气象站逐日最大风速风向观测资料,分析了辽宁省海岸带大风日数的时空变化特征。结果表明:1971—2015年辽宁省海岸带春季大风高发,冬季次之,夏季大风发生最少;渤海北部地区和渤海海峡大风日数月变化均呈双峰型,4月为大风活动高峰期;海岸带大风主要以偏北风和偏南风为主,东西风出现次数较少;除盖县外其他海岸带气象站点的大风日数均呈显著减少的趋势,渤海海峡平均大风日数减少最明显,减少速率为19.3 d/10 a,其次为渤海北部地区,黄海北部地区大风日数减少速率相对缓慢。渤海北部地区和渤海海峡大风日数主要存在7 a左右的主周期,并从20世纪80年代开始发生突变减少;黄海北部地区大风日数则以11 a的变化周期为主,且从20世纪70年代开始发生突变减少。近45 a辽宁省海岸带年平均大风日数存在3个高值中心和3个低值中心,高值中心分别位于旅顺口和大连地区、长海、锦州盘山一带;低值中心主要分布在东港、绥中、普兰店附近,大风高发区和低发区交叉分布。西风指数增强导致经向环流减弱,不利于冷暖空气交换;亚洲区极涡面积和北半球极涡面积指数显著下降,且极涡中心位置呈北进状态,说明冷空气活动强度和发生频率有所减少;西伯利亚高压强度减弱,降低了东西方向的气压梯度;寒潮和强冷空气出现次数逐渐减少,气温日较差显著减小,可能是辽宁省海岸带大风日数减少的重要原因。
Based on the daily maximum wind speed and wind direction data of coastal zone weather stations in Liaoning province from 1971 to 2015,the temporal and spatial distribution characteristics of gale days and its variation were analyzed.The results show that the number of gale days is highest in spring and followed by winter and summer.The monthly variation of the number of gale days is a bimodal type in the northern part of Bohai Sea and Bohai Strait with a peak value in April.The northerly and southerly winds dominate in the coastal zone and the east and west winds occur infrequently.The number of gale days in most of weather stations of coastal zone shows a decreasing trend except the Gai county.The decreasing trend in the Bohai strait is most significant with a rate of 19.3 d/10 a,f ollowed by the northern part of the Bohai Sea.The decrease rate in the northern part of the Yellow Sea is relatively smaller.In addition,the number of gale days in the northern part of Bohai Sea and the Bohai Strait show a main cycle of about 7 years,and a decreasing climate abrupt change occurs in the 1980s.Besides an 11-year cycle occurs in the northern part of the Yellow Sea and an abrupt decreasing appears after the 1970s.There are three high-value centers including Lüshunkou-Dalian,Changhai and Jinzhou-Panshan and three low-value centers such as Donggang,Suizhong and Pulandian area for the averaged annual gale days in the coastal zone of Liaoning province in recent 45 years.The high and low incidence areas demonstrate a cross-distribution.The zonal index enhancement leads to a weakening of meridional circulation,which is not favorable to the exchange between cold and warm air.The Asia polar Vortex Area Index and the Northern Hemisphere Polar Vortex Area Index decrease significantly and the polar vortex central position is northward propelling,implying that the intensity and frequency of the cold air activity are reducing.The weakening Siberia high intensity cuts down the pressure gradient in the east-west direction.As a result,the decreasing frequencies of cold wave and strong cold air and the daily range of temperature may be the important reason for decreasing the number of gale days in the coastal zone.
Based on the daily maximum wind speed and wind direction data of coastal zone weather stations in Liaoning province from 1971 to 2015,the temporal and spatial distribution characteristics of gale days and its variation were analyzed.The results show that the number of gale days is highest in spring and followed by winter and summer.The monthly variation of the number of gale days is a bimodal type in the northern part of Bohai Sea and Bohai Strait with a peak value in April.The northerly and southerly winds dominate in the coastal zone and the east and west winds occur infrequently.The number of gale days in most of weather stations of coastal zone shows a decreasing trend except the Gai county.The decreasing trend in the Bohai strait is most significant with a rate of 19.3 d/10 a,f ollowed by the northern part of the Bohai Sea.The decrease rate in the northern part of the Yellow Sea is relatively smaller.In addition,the number of gale days in the northern part of Bohai Sea and the Bohai Strait show a main cycle of about 7 years,and a decreasing climate abrupt change occurs in the 1980s.Besides an 11-year cycle occurs in the northern part of the Yellow Sea and an abrupt decreasing appears after the 1970s.There are three high-value centers including Lüshunkou-Dalian,Changhai and Jinzhou-Panshan and three low-value centers such as Donggang,Suizhong and Pulandian area for the averaged annual gale days in the coastal zone of Liaoning province in recent 45 years.The high and low incidence areas demonstrate a cross-distribution.The zonal index enhancement leads to a weakening of meridional circulation,which is not favorable to the exchange between cold and warm air.The Asia polar Vortex Area Index and the Northern Hemisphere Polar Vortex Area Index decrease significantly and the polar vortex central position is northward propelling,implying that the intensity and frequency of the cold air activity are reducing.The weakening Siberia high intensity cuts down the pressure gradient in the east-west direction.As a result,the decreasing frequencies of cold wave and strong cold air and the daily range of temperature may be the important reason for decreasing the number of gale days in the coastal zone.
引文
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[15]高婧,井立军,井立红,等.新疆塔城地区大风年际振荡及环流背景[J].干旱区地理,2011,34(2):284-291.
[16]龚道溢,王绍武.西伯利亚高压的长期变化及全球变暖可能影响的研究[J].地理学报,1999,54(2):125-133.
[17]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.GB/T 20484-2006,冷空气等级[S].北京:中国标准出版社,2006.
[18]金巍,周广胜,曲岩.1971-2000年营口地区大风特征及其变化分析[J].气候变化研究进展,2009,5(4):237-240.
[19]Jiang Y,Luo Y,Zhao Z C,et al.Changes in wind speed over China during 1956-2004[J].Theoretical and Applied Climatology,2010,99(3/4):421-430.
[2]辛吉武,翁小芳,许向春,等.琼州海峡南北海岸带大风的天气气候特征[J].气象,2009,35(11):71-77.
[3]王慧,隋伟辉.基于CCMP风场的中国近海18个海区海面大风季节变化特征分析[J].气象科技,(4):720-725.
[4]高瑞华,申培鲁,高慧,等.渤海海峡大风日数的变化趋势分析[J].海洋预报,2010,27(1):39-43.
[5]宫攀,孙即霖,公延华.黄海大风日数长期变化特征研究[J].现代农业科技,2013(3):185-187.
[6]吴曼丽,陈宇,王瀛,等.黄渤海北部沿海大风时空变化特征[J].气象与环境学报,2012,28(6):65-71.
[7]魏凤英.现代气候统计诊断与预测技术(2版)[M].北京:气象出版社,2007:23-104.
[8]杨丽娟,张白桦,叶旭桢.快速傅里叶变换FFT及其应用[J].光电工程,2004,31(S1):1-3,7.
[9]高瑞华.渤海海峡大风气候特征的初步分析[D].兰州:兰州大学,2007.
[10]阎访,岳艳霞,张秉祥,等.石家庄地区大风日数气候变化特征[J].气象与环境学报,2013,29(2):81-88.
[11]Rossby C G.Relation between variations in the intensity of the zonal circulation of the atmosphere and the displacements of the semi-permanent centers of action[J].Journal of Marine Research,1939,2:38-55.
[12]龚道溢,王绍武.冬季西风环流指数的变率及其与北半球温度变化的关系研究[J].热带气象学报,2002,18(2):104-110.
[13]林振敏,施能.北半球冬季大气环流遥相关型特征与我国区域气候[J].气象科技,2004,32(5):333-337,342.
[14]邓伟涛,孙照渤.冬季北极涛动与极涡的变化分析[J].南京气象学院学报,2006,29(5):613-619.
[15]高婧,井立军,井立红,等.新疆塔城地区大风年际振荡及环流背景[J].干旱区地理,2011,34(2):284-291.
[16]龚道溢,王绍武.西伯利亚高压的长期变化及全球变暖可能影响的研究[J].地理学报,1999,54(2):125-133.
[17]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.GB/T 20484-2006,冷空气等级[S].北京:中国标准出版社,2006.
[18]金巍,周广胜,曲岩.1971-2000年营口地区大风特征及其变化分析[J].气候变化研究进展,2009,5(4):237-240.
[19]Jiang Y,Luo Y,Zhao Z C,et al.Changes in wind speed over China during 1956-2004[J].Theoretical and Applied Climatology,2010,99(3/4):421-430.