中国东部雨季降水事件的静默时间特征及内在动力学机制初探

为了挖掘降水的内在非线性动力学机制,基于1960—2017年4—9月的中国日降水数据,利用百分位阈值法确定不同强度的降水事件,定义相邻同强度降水事件之间的间隔时间为“静默时间”,描述同阈值降水事件再次发生的历时长短。“平均静默时间”可以表征不同强度降水事件的群发性特征,即某一时段内,平均静默时间越短（长）,同类型降水事件再次发生的历时越短（长）,其群发性程度越强（弱）。分析不同强度降水事件的平均静默时间在中国东部地区的空间分布和时间演变特征表明: 1960—2017年,一般强度降水事件在长江中游地区较其余地区群发性强,而东北南部地区则较弱; 极端降水事件在中国东部北方地区群发性较强,而在南方地区则偏弱。就气候态演化过程而言,一般强度降水事件的群发性在长江以南地区有所增强,在东北南部地区则呈减弱趋势;极端降水事件的群发性特征在中国东部北方地区不断减弱,但在南方地区持续增强。各站点降水事件静默时间的概率密度函数均呈幂律分布,且时、空上呈无标度特征,表明日降水系统为现实世界中的自组织临界系统,为时间序列分析角度理解降水事件内在非线性动力学机制提供了新的视角。      

气候变化背景下湖北省高温干旱复合灾害变化特征

全球气候变化造成的极端气候事件频发已成为科学界和人类社会共同面临的挑战。气候变化驱动因素多样,时空过程复杂,全球不同区域存在显著差异。基于1961—2022年湖北省76个国家气象站逐日降水、气温等观测数据,根据区域性高温过程监测指标和区域性干旱过程监测评估方法,对湖北省1961年以来的区域性高温和干旱事件进行识别,在此基础上分析事件发生频率、持续时间、强度及其影响的变化特征。结果表明：区域性高温事件趋多增强且有连年发生的趋势;区域性干旱事件频次变化趋势不显著,但呈现群发、连发和重发特征;高温干旱复合事件有显著增加、间隔缩短的趋势。2022年夏季高温过程综合强度为1961年以来最强,与长江流域性干旱叠加,产生了从气象干旱到水文干旱、农业干旱和社会经济干旱的链式复杂影响。在全球变暖背景下,湖北省极端高温和干旱及其复合事件频发可能成为气候新常态,亟需加强极端事件的成因及其灾害风险评估研究,提高应对极端和复合型灾害的能力。     

安徽省近40a极端温度事件的气候特征分析

利用1975—2014年安徽省77个观测站的日最高温度、最低温度和平均气温资料,对近40 a极端温度事件的时空分布特征进行分析。结果表明:安徽省冬季极端低温事件的发生频次分布,总体呈北多南少,地区差异较大,极端低温事件发生次数最多的是宿州萧县。近40 a间冬季的极端低温事件发生减少趋势显著,与冬季平均温度的显著上升相对应。年极端最低温度年际变化趋势不明显,且极端低温的发生频次与强度并不对应。夏季极端高温事件发生频次较多区域为江南。1975—2014年,夏季极端高温事件发生呈整体增多趋势,但趋势不显著。年极端最高温度的时间序列,与极端高温事件发生频次的时间序列是相对应的,呈现明显的正相关。从MK突变上看,年极端低温和高温事件发生均存在突变。分析合成环流场发现,冬季极端冷事件发生时,亚洲中高纬度环流的经向度明显增强;夏季极端暖事件的发生与副高的明显西伸增强维持有关。     

近70a来中亚极端高温事件时空分布

基于NCEP/NCAR 1948—2017年逐日平均气温资料,利用百分位阈值法确定中亚地区极端高温事件的阈值,进而分析该地区近70 a极端高温事件强度、频次时空分布特征。结果表明:中亚地区暖季平均气温的空间分布受地形影响显著,从西南向东北逐渐降低。极端高温事件的强度和频次在1967年前后发生年代际转折,其中强度在转折后要显著高于转折前,频次在转折前呈现负趋势、转折后转变为正趋势。极端高温事件发生的区域也存在显著的年代际变化特征。极端高温事件强度趋势增加最显著的地区位于乌兹别克斯坦西部,负趋势最显著的区域位于中国南疆;频次趋势增加最显著区域位于哈萨克斯坦西部的乌拉尔地区,负趋势显著区域则位于帕米尔高原。     

中国极端温度的群发性研究

从极端事件再现时间的角度研究了中国极端高、低温事件再现时间序列的长程相关性、群发性以及二者的关系。发现极端温度事件再现时间序列具有长程相关性,表征长程相关性的标度指数分布存在着明显的区域性特征,并与大气环流有关,当中国大陆在盛夏或隆冬稳定的西风环流控制下,极端温度的长程相关性较好,标度指数较大。通过定义极端事件的群发指数,对极端高、低温进行研究,发现具有长程相关性再现时间序列的极端温度呈现群发现象,且极端温度再现时间序列的标度指数和群发指数二者在空间分布上有较好的对应,极端温度再现时间序列的长程相关性可能是导致极端温度群发性的原因。从年际变化的角度看,极端高温Ⅰ级群发区域的群发指数增长趋于平缓,而极端低温Ⅰ级群发区域的群发指数有下降趋势,这与近几十年来全球变暖一致。在年代际尺度上,群发指数分布的演变特征明显,极端高温Ⅰ级群发区域总体面积变化不大,而极端低温Ⅰ级群发区域面积明显减少。因此,极端低温事件群发性减弱很可能是年代际气候变暖的主要原因。     

丘陵地区降水诱发滑坡地质灾害的阈值分析——以巴中市恩阳区为例

利用降水阈值模型对典型丘陵地区的227个滑坡点进行降水诱发滑坡地质灾害的分析。结果表明：2009—2018年227例降水型滑坡中,降水引起当日发生2起及2起以上滑坡事件的共143起滑坡,约占总滑坡起数的63%;降水引起当日发生3起及3起以上滑坡事件的共99起,约占总滑坡起数的43%。因此,恩阳区受降水影响的滑坡事件具有群发性特征。利用降雨和滑坡数据可以获得恩阳区降水诱发滑坡的降水强度—降水历时阈值曲线和具有滑坡群发性特征的降水强度—降水历时阈值曲线。此外,当0 2时,选择群发性的降水阈值曲线进行预警,以此得到组合模型;组合模型解决了常规的滑坡降水阈值曲线对降水是否诱发滑坡的预警空报率较高,而群发性的滑坡降水阈值曲线的漏报率较高的问题。     

石羊河流域中下游高温事件气候特征

根据石羊河流域中游(武威)和下游(民勤)气象站1960—2015年逐日最高、平均气温观测数据,采用固定阈值法(天气标准)和百分位阈值法(平均标准)定义了高温事件,运用气候统计学方法分析了该区域高温事件强度、日数和极值的变化特征。统计结果显示,中、下游年代、年天气标准和平均标准高温事件强度总体上呈增强和日数呈增多趋势,2010—2015年高温事件强度增强和日数增多趋势明显,高温事件极值也呈增强趋势。高温事件出现在5—9月,高温事件强度和日数的高峰值均在7月,依次向两端递减。高温事件强度和日数均为下游>中游,说明闷热天气持续时间下游比中游更长。高温事件中、下游年天气标准强度和日数时间序列没有发生周期性变化,平均标准强度和日数时间序列均存在着5～7 a的准周期变化。高温事件中、下游天气标准强度和日数以及平均标准强度均没有发生气候突变,平均标准日数发生了气候突变,突变时间中游在1997年、下游在1996年。年高温事件存在一定的异常性,高温事件强度和日数正常年份概率在58.9%～73.2%,对生命健康和安全生产造成危害的强度偏强和特强年份概率在14.3%～16.9%、日数偏多和特多年份概率在14.3%～21.4%。     

石羊河流域中下游高温事件的气候特征

根据石羊河流域中游(武威)和下游(民勤)气象站1960—2015年逐日最高、平均气温观测数据,采用固定阈值法(天气标准)和百分位阈值法(平均标准)定义了高温事件,运用气候统计学方法分析了该区域高温事件强度、日数和极值的变化特征。统计结果显示,中、下游年代、年天气标准和平均标准高温事件强度总体上呈增强和日数呈增多趋势,2010—2015年高温事件强度增强和日数增多趋势明显,高温事件极值也呈增强趋势。高温事件出现在5—9月,高温事件强度和日数的高峰值均在7月,依次向两端递减。高温事件强度和日数均为下游中游,说明闷热天气持续时间下游比中游更长。高温事件中、下游年天气标准强度和日数时间序列没有发生周期性变化,平均标准强度和日数时间序列均存在着5～7 a的准周期变化。高温事件中、下游天气标准强度和日数以及平均标准强度均没有发生气候突变,平均标准日数发生了气候突变,突变时间中游在1997年、下游在1996年。年高温事件存在一定的异常性,高温事件强度和日数正常年份概率在58.9%～73.2%,对生命健康和安全生产造成危害的强度偏强和特强年份概率在14.3%～16.9%、日数偏多和特多年份概率在14.3%～21.4%。     

近49年来湖北省极端高温事件及其对区域增温的贡献

收集了湖北省1961—2009年76个站点的逐日温度数据,选择其中通过均一化检验的33个站点作为研究对象,分析了湖北省年极端高温的发生频率、强度变化及对区域性增温的贡献。研究表明:湖北省年极端高温发生频次与海拔高度相关性较好,极端高温发生频次呈东西减少、中部增加的趋势;极端高温发生频率的地理分布一致性较好,江汉平原及东北部易出现极端高温事件;西南部的极端高温强度较弱;极端高温事件的发生频率与夏季平均气温呈正相关,东北部的相关程度较西部显著。     

1961—2010年山西省极端气温年均发生频率的时空特征分析

利用山西省61个气象站点逐日最高温度、最低温度资料,采用百分位值定义法、Mann原Kendall突变检验法和Morlet小波变换等方法,分析了山西省近50 a极端温度事件年均发生频率的时空特征,结果表明：1961年以来,山西省极端高温事件年均发生频率呈显著增加趋势,趋势为6.1 d/10 a,与此同时,极端低温事件年均发生频率呈显著减少趋势,且极端气温事件的变化存在明显的区域差异;极端高温和极端低温年均发生频率均发生了突变现象,变化趋势均在20世纪90年代以来更加显著;极端高温和极端低温事件年均发生频率均呈显著波动变化,在整个研究期间极端高温存在5～6a、4～8a显著周期,极端低温存在4～5a显著周期。     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.     

A COMPARATIVE ANALYSIS OF ATMOSPHERIC AND OCEANIC CONDITIONS BEFORE THE OCCURRENCE OF TWO TYPES OF EL NIO EVENTS

The atmospheric and oceanic conditions before the onset of EP El Ni?o and CP El Ni?o in nearly 30 years are compared and analyzed by using 850 hPa wind, 20℃ isotherm depth, sea surface temperature and the Wheeler and Hendon index. The results are as follows: In the western equatorial Pacific, the occurrence of the anomalously strong westerly winds of the EP El Ni?o is earlier than that of the CP El Ni?o. Its intensity is far stronger than that of the CP El Ni?o. Two months before the El Ni?o, the anomaly westerly winds of the EP El Ni?o have extended to the eastern Pacific region, while the westerly wind anomaly of the CP El Ni?o can only extend to the west of the dateline three months before the El Ni?o and later stay there. Unlike the EP El Ni?o, the CP El Ni?o is always associated with easterly wind anomaly in the eastern equatorial Pacific before its onset. The thermocline depth anomaly of the EP El Ni?o can significantly move eastward and deepen. In addition, we also find that the evolution of thermocline is ahead of the development of the sea surface temperature for the EP El Ni?o. The strong MJO activity of the EP El Ni?o in the western and central Pacific is earlier than that of the CP El Ni?o. Measured by the standard deviation of the zonal wind square, the intensity of MJO activity of the EP El Ni?o is significantly greater than that of the CP El Ni?o before the onset of El Ni?o.     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

正ERRATUM to: Atmospheric and Oceanic Science Letters, 4(2011), 124-130 On page 126 of the printed edition (Issue 2, Volume 4), Fig. 2 was a wrong figure because the contact author made mistake giving the wrong one. The corrected edition has been updated on our website. The editorial office is sincerely sorry for any     

Index to Vol.31

正AN Junling;see LI Ying et al.;(5),1221—1232AN Junling;see QU Yu et al.;(4),787-800AN Junling;see WANG Feng et al.;(6),1331-1342Ania POLOMSKA-HARLICK;see Jieshun ZHU et al.;(4),743-754Baek-Min KIM;see Seong-Joong KIM et al.;(4),863-878BAI Tao;see LI Gang et al.;(1),66-84BAO Qing;see YANG Jing et al.;(5),1147—1156BEI Naifang;     

Information for Contributors

正Journal of Meteorological Research is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at introduction of the current advancements in atmospheric sciences in China.The journal columns include Articles.Note and Correspondence,and research letters.Contributions from all over the world are welcome.