On the relationship between winter thunder and the climatic change in China in the past 2200 years

An analysis of winter thunder records in China from 250 B.C. to A.D. 1900 shows that there is a relationship between the pattern of winter thunder frequency fluctuation with that of temperature fluctuation. We hypothesized that such a temperature—thunder relationship may possibly be due to the strong frontal movement by cold air masses of well-defined low temperature.     

Transient twenty-first century changes in daily-scale temperature extremes in the United States

A key question for climate mitigation and adaptation decisions is how quickly significant changes in temperature extremes will emerge as greenhouse gas concentrations increase, and whether that emergence will be uniform between hot and cold extremes and across different geographic areas. We use a high-resolution, multi-member ensemble climate model experiment over the United States (U.S.) to investigate the transient response of the annual frequency, duration and magnitude of 8 daily-scale extreme temperature indices during the twenty-first century of the A1B emissions scenario. We evaluate the time of emergence of a permanent exceedance (PE) above the colder part of the historical (1980–2009) extremes distribution, and the time of emergence of a new norm (NN) centered on the historical maxima (for hot extremes) or minima (for cold extremes). We find that during the twenty-first century, hot extremes permanently exceed the historical distribution’s colder half over large areas of the U.S., and that the hot extremes distribution also becomes centered on or above the historical distribution’s maxima. The changes are particularly robust for the exceedance of the annual 95th percentile of daily maximum temperature over the West and the Northeast (with the earliest emergence of a PE by 2030 and of a NN by 2040), for warm days over the Southwest (with the earliest emergence of a PE by 2020 and of a NN by 2030), and tropical nights over the eastern U.S. (with the earliest emergence of a PE by 2020 and of a NN by 2030). Conversely, no widespread emergence of a PE or a NN is found for most cold extremes. Exceptions include frost day frequency (with a widespread emergence of a PE below the historical median frequency by 2030 and of a NN by 2040 over the western U.S.), and cold night frequency (with an emergence of a PE below the historical median frequency by 2040 and of a NN by 2060 in virtually the entire U.S.). Our analysis implies a transition over the next half century to a climate of recently unprecedented heat stress in many parts of the U.S., along with cold extremes that, although less frequent, remain at times as long and as severe as are found in the current climate.     

Thunder Events in China: 1980-2008

Using data collected at 517 weather stations in contiguous China over the period 1980-2008,characteristics of thunder events have been investigated.These characteristics include geographical distribution,interdecadal variation,annual variation,and seasonal variation.The areas with the highest frequencies of thunder events are located in the central Tibetan Plateau,Yunnan,Guangxi,and Guangdong.The annual number of thunder days increases from northern to southern China.But the frequency of thunder events over mountains and plateaus is much higher than the frequency of events over plains in the same latitude.The interdecadal variation of events shows that the frequency of thunder occurrences was highest during the 1980s,decreased during the 1990s,and increased slightly afterwards.Thunder occurrences vary with the season,northward in May and retreating southward in September.     

Atlantic Basin Hurricanes: Indices of Climatic Changes

Accurate records of basinwide Atlantic and U.S. landfalling hurricanes extend back to the mid 1940s and the turn of the century, respectively, as a result of aircraft reconnaissance and instrumented weather stations along the U.S. coasts. Such long-term records are not exceeded elsewhere in the tropics. The Atlantic hurricanes, U.S. landfalling hurricanes and U.S. normalized damage time series are examined for interannual trends and multidecadal variability. It is found that only weak linear trends can be ascribed to the hurricane activity and that multidecadal variability is more characteristic of the region. Various environmental factors including Caribbean sea level pressures and 200mb zonal winds, the stratospheric Quasi-Biennial Oscillation, the El Niño-Southern Oscillation, African West Sahel rainfall and Atlantic sea surface temperatures, are analyzed for interannual links to the Atlantic hurricane activity. All show significant, concurrent relationships to the frequency, intensity and duration of Atlantic hurricanes. Additionally, variations in the El Niño-Southern Oscillation are significantly linked to changes in U.S. tropical cyclone-caused damages. Finally, much of the multidecadal hurricane activity can be linked to the Atlantic Multidecadal Mode - an empirical orthogonal function pattern derived from a global sea surface temperature record. Such linkages may allow for prediction of Atlantic hurricane activity on a multidecadal basis. These results are placed into the context of climate change and natural hazards policy.     

基于雷声到达时间差的单站闪电通道三维定位系统

利用麦克风阵列采集雷声信号,设计了一套由麦克风阵列和便携式数据采集存储设备组成的单站闪电通道三维定位系统,采用CCF相关函数法计算了雷声脉冲信号到达不同麦克风的时间差,通过最小二乘法获得声源的方向角和仰角信息,并结合声源与麦克风阵列的距离定位声源的三维位置。对一次包括8次回击的人工触发闪电过程进行了观测,得到多个声源点的三维定位信息。系统的定位结果与高速摄像的观测结果具有较好的一致性,定位方法合理、可行,为进一步研发便携式闪电通道三维定位系统奠定了基础。     

RELATIONSHIPS BETWEEN ZONAL WIND ANOMALIES IN HIGH AND LOW TROPOSPHERE AND ANNUAL FREQUENCY OF NW PACIFIC TROPICAL CYCLONES

Relationships between large-scale zonal wind anomalies and annual frequency of NW Pacific tropical cyclones and possible mechanisms are investigated with the methods of correlation and composition.It is indicated that when △ U200-△U850 ＞0 in the eastern tropical Pacific and △ U200- △U850 ＜0 in western tropical Pacific, the Walker cell is stronger in the Pacific tropical region and the annual frequency of NW Pacific tropical cyclone are above normal. In the years with zonal wind anomalies, the circulation of high and low troposphere and the vertical motions in the troposphere have significant characteristics. In the time scale of short-range climate prediction, zonal wind anomalies in high and low troposphere are useful as a preliminary signal of the annual frequency prediction of NW Pacific tropical cyclones.     

TBB资料揭示的热带大气低频振荡周期的年变化特征

１９８０－１９９２年ＧＭＳＴＢＢ格点资料，分析了１３年平均的ＴＢＢ功率谱随时间的变化，讨论了低频振荡周期的年变化特征及其可能的成因。结果表明，热带大气低频振荡周期有很明显的年变化。北半球热速睦区比赤道附近和南半球热带地区的周期变化幅度更大。总体上，冬季比夏，秋季低频振荡周期更长。     

Impacts of SST and SST Anomalies on Low-Frequency Oscillation in the Tropical Atmosphere

Considering the multiscale character of LFO effects of SST on LFO in the tropical atmosphere （low-frequency oscillation） in the tropical atmosphere, the are discussed by using an absolute ageostrophic, baroclinic model. Here, SST effects include sea surface heating and forcing of SST anomalies （SSTAs）. Studies of the influences of sea surface heating on LFO frequency and stability show that sea surface heating can slow the speed of waves and lower their frequency when SST is comparatively low; while higher SST leads to unstable waves and less periods of LFO. Since the impact of a SSTA on ultra-long waves is more evident than that on kilometer-scale waves, long-wave approximation is used when we continue to study the effect of SSTAs. Results indicate that SSTAs can lead to a longer period of LFO, and make waves unstable. In other words, positive （negative） SSTAs can make waves decay （grow）.     

Impacts of SST and SST Anomalies on Low-Prequency Oscillation in the Tropical Atmosphere

Considering the multiscale character of LFO (low-frequency oscillation) in the tropical atmosphere, the effects of SST on LFO in the tropical atmosphere are discussed by using an absolute ageostrophic, baroclinic model. Here, SST effects include sea surface heating and forcing of SST anomalies (SSTAs). Studies of the influences of sea surface heating on LFO frequency and stability show that sea surface heating can slow the speed of waves and lower their frequency when SST is comparatively low; while higher SST leads to unstable waves and less periods of LFO. Since the impact of a SSTA on ultra-long waves is more evident than that on kilometer-scale waves, long-wave approximation is used when we continue to study the effect of SSTAs. Results indicate that SSTAs can lead to a longer period of LFO, and make waves unstable. In other words, positive (negative) SSTAs can make waves decay (grow).     

雷电过程中大气电场信号处理方法探究

基于天津市蓟州区大气电场探测数据和闪电定位数据，利用功率谱分析、小波降噪和快速傅里叶变换等信号处理方法，分析了雷电天气过程中地面大气电场变化特征。结果表明，雷电过程中大气电场能量主要集中在低频部分，利用sym5小波函数进行7层或8层分解，提取的低频信号能够反映大气电场的主要变化特征。在首次闪电发生前1小时，大气电场的频谱幅值起伏变化明显，且远高于非雷电天气电场频谱幅值。通过欧氏距离判别法，判断大气电场频谱特征更接近雷电天气还是非雷电天气，可为雷电预报预警提供参考。     

云南两次中尺度对流雷暴系统演变和地闪特征

在利用NCEP/NCAR再分析资料诊断分析2010年9月21—23日中尺度对流雷暴系统形成的环流背景基础上,通过云南省闪电定位系统地闪监测资料和FY-2E卫星云图资料的同步叠加, 分析两个中尺度雷暴系统的演变和地闪特征。结果表明:台风凡亚比 (1011) 西行减弱的热带低压为中尺度对流雷暴系统提供有利的暖湿和抬升动力环流背景,促使中尺度弧状对流云带、中尺度雷暴云团和中尺度对流复合体生成和发展。雷暴云团结构和地闪活动空间分布不均匀并随时间变化,且正、负地闪频数与云顶亮温 (TBB) 相关,当TBB降低和等值线密度变大,雷暴云团发展,低TBB中心偏于云团的前部云区,负地闪频数剧增;当TBB达最低值时,雷暴云团成熟,负地闪频数达峰值,正地闪出现;当TBB升高且等值线密度变小时,雷暴云团减弱,低TBB中心靠近云团中心,负地闪频数迅速减小,正地闪频数达到峰值;密集的负地闪出现在雷暴云团前部大的TBB梯度区和TBB不大于-56℃的低值中心附近,正地闪分散在TBB不大于-56℃的低值中心附近,偏于负地闪区域后部发生。     

某通讯基站对炸药库雷击风险的影响分析

以移动通讯基站为例,从基站“引雷”作用的角度,通过理论和计算分析,认为基站能使周边环境雷击频率和雷电强度增加,但基站周边建筑物自身受直击雷危害的影响远大于受基站雷击感应的影响,所以基站周边建筑物自身要有完善的防雷装置才能保证其安全。     

某通讯基站对炸药库雷击风险的影响分析

以移动通讯基站为例，从基站“引雷”作用的角度，通过理论和计算分析，认为基站能使周边环境雷击频率和雷电强度增加，但基站周边建筑物自身受直击雷危害的影响远大于受基站雷击感应的影响，所以基站周边建筑物自身要有完善的防雷装置才能保证其安全。     

Intense tropical cyclogenesis over the northwest Australian region in 1998/1999: Causal factors

Summary The 1998/99 tropical cyclone (TC) season over northwest Australia was notable for an above average number of TCs (seven compared to five on average) and a number of unusually intense TCs making landfall (three category 5 TCs). The active 1998/99 TC season is attributed here to a combination of a number of broad-scale features over the south east Indian Ocean and the Australian region, with identifiable precursors favoring tropical cyclogenesis. These precursors include: below normal MSLP, abnormally warm ocean temperatures, above average relative humidity in the low- to mid-tropospheric levels and weak wind shears in the genesis region under study, that is, between 10° S to 20° S and 105° E to 135° E. These favorable conditions first appeared as early as August 1998. The appearance of favorable conditions so far ahead of the TC season indicates that they are the likely cause of the enhanced TC activity rather than simply an effect. Although the season as a whole was an active one, strong intra-seasonal variability was evident in that there were two named TCs in December 1998, forming within three days of each other. Only one formed in January 1999 and none in February. By contrast, in March and April 1999, TC activity was enhanced once again, with four named TCs, three of which attained category 5 status. The importance of the above-mentioned precursors in favoring tropical cyclogenesis during the 1998/99 season is discussed in terms of seasonal time scales of the preceding spring and down to synoptic and mesoscale time scales ranging from several days to 48 hours or less. Received October 5, 2001 Revised December 28, 2001     

防雷业务综合管理系统

利用网络技术,遵循TCP/IP协议,采用B/S结构的网络计算模式和 SQL Server 2000数据库及数据安全保护措施,研制防雷业务综合管理系统。系统可提供对防雷行政执法、新建建（构）筑防雷装置设计审核与竣工验收、防雷装置检测等方面相关信息的采集、整理,对防雷业务的各种用户信息资料进行远程传输及在线操作,实现防雷业务综合管理的网络化、自动化和科学化。     

The 1976/77 transition in precipitation over the Americas and the influence of tropical sea surface temperature

Most major features of the interdecadal shift in boreal winter-spring precipitation over the American continents associated with the 1976–1977 transition are reproduced in atmospheric general circulation model (GCM) simulations forced with observed sea surface temperature (SST). The GCM runs forced with global and tropical Pacific SSTs produce similar multidecadal changes in precipitation, indicating the dominant influence of tropical Pacific SST. Companion experiments indicate that the shift in mean conditions in the tropical Pacific is responsible for these changes. The observed and simulated “post- minus pre-1976” difference in Jan–May precipitation is wet over Mexico and the southwest U.S., dry over the Amazon, wet over sub-Amazonian South America, and dry over the southern tip of South America. This pattern is not dramatically different from a typical El Niño-induced response in precipitation. Although the interdecadal (post- minus pre-1976) and interannual (El Niño?La Niña) SST anomalies differ in detail, they produce a common tropics-wide tropospheric warmth that may explain the similarity in the precipitation anomaly patterns for these two time scales. An analysis of local moisture budget shows that, except for Mexico and the southwest U.S. where the interdecadal shift in precipitation is balanced by evaporation, elsewhere over the Americas it is balanced by a shift in low-level moisture convergence. Moreover, the moisture convergence is due mainly to the change in low-level wind divergence that is linked to low-level ascent and descent.     

近30年影响我国东南沿海的热带气旋降水强度变化特征分析

利用中国地面台站逐日降水资料和中国气象局上海台风研究所整编的热带气旋最佳路径资料研究了1978～2007年影响我国热带气旋降水强度的变化及其对我国东南沿海盛夏降水变化的影响.近30年影响我国东南沿海盛夏的热带气旋降水增加是导致我国东南沿海盛夏降水显著增加的主要原因.仅从热带气旋降水来看,东南沿海和内陆(包括江西、湖南东部和湖北南部)热带气旋降水强度显著增加,而影响热带气旋降水频次略有增加.通过对雨量站与引起降水热带气旋的中心距离的变化分析发现:内陆地区影响热带气旋距离显著下降,近距离热带气旋引起降水的增加,是该区域热带气旋降水强度增加的主要来源;而东南沿海地区近距离热带气旋降水增加不明显,热带气旋降水强度的增加主要由于同距离热带气旋降水强度的增加.热带气旋经过频次的空间的变化结果证实,近30年经过中国沿海的TC个数变化不大,仅福建沿海一带略有增加,而内陆地区则增加明显,且经过该区域时热带气旋移动速度变慢,这均与该区域近距离热带气旋降水的增加一致.     

The role of the Indian Ocean in determining the tropical pacific SST response to radiative forcing in an idealized model

The complexity of the tropical climate system demands the development of a hierarchy of models to ensure our understanding of its response to anthropogenic forcing. The response of the tropical Pacific Ocean to radiative forcing has been studied previously with a box model. The model has provided insights into the tropical Pacific climate change that are otherwise not easily attainable. But that model only encompasses the tropical Pacific region. Recent studies have also shown that the Indian Ocean (IO) may be important in the response of the Pacific Walker circulation to radiative forcing, raising the need to expand the model to take into account the role of IO. This study presents the results concerning the tropical Pacific response to radiative forcing from an expanded-box model that includes the tropical IO, which influences the tropical Pacific through an inter-basin SST gradient.The three-box model predicts an enhanced zonal SST gradient in tropical Pacific in response to the increased radiative forcing, similar to the previous two-box model. It is further noted that in the three-box model, a warmer IO relative to the Pacific enhances Pacific easterlies and subsequently strengthens the equatorial ocean circulation. Because of this ocean dynamical cooling, the warming response in the Pacific is effectively reduced in the three-box model that includes the role of IO compared with that in the two-box model. The role of the IO warming trend in enhancing the Pacific trade winds is confirmed using an atmospheric general circulation model experiment. These results may help to fully explain the relatively small observed warming trend in the tropical Pacific compared to that in the tropical IO evident in 20th century SST reconstructions.     

近71a影响黑龙江省热带气旋统计特征分析

利用中国气象局上海台风研究所整编的1949—2019年热带气旋数据,统计分析近71 a影响黑龙江省的热带气旋发生时间、频率、强度、移动路径等特征。结果表明：近71 a影响黑龙江的热带气旋共有77个,平均1.08个·a^-1,其中有28 a没有热带气旋影响黑龙江;近10 a是黑龙江受热带气旋影响的活跃期,西北太平洋生成的热带气旋频数与影响黑龙江的频数没有直接相关关系,出现El Ni1o或La Ni1a现象时对影响黑龙江的热带气旋起抑制作用;热带气旋影响黑龙江最早出现在5月,最晚出现在9月,8月出现频率最高,“七下八中下”是每年的活跃阶段;在强度上,影响黑龙江的超强台风居多,但近年趋于减少,更多低级别的热带气旋可维持较长生命史北上产生影响;牡丹江市为黑龙江最易受热带气旋影响的地区;按移动路径可将影响黑龙江的热带气旋分为两类,分别为北上热带气旋和偏东路径热带气旋,其中北上热带气旋又可进一步分为七类,其中经朝鲜半岛东转向出现的频次最多,但对黑龙江影响相对较小;经朝鲜半岛北上和高纬东转向更容易给黑龙江带来严重的风雨影响。     

Spatial and Temporal Variations of Tropical Cyclones at Different Intensity Scales over the Western North Pacific from 1945 to 2005

The tropical cyclone （TC） track data provided by the Joint Typhoon Warning Center （JTWC） of the U.S. Navy over the western North Pacific （including the South China Sea） from 1945 to 2005 are employed to analyze the temporal and spatial variations of TCs of different intensity scales. Most of the TCs occurred between 15° and 25°N, from the northern part of the South China Sea to the eastern part of the Bashi Channel until near 140°E. Most of the severe and super typhoons occurred over waters from the eastern part of the Bashi Channel to about 140°E. The TCs in a weakening or steady state take up a weak majority in the area west of 123°E and north of 20°N; those in an intensifying or steady state are mostly found in the area east of 123°E and south of 20°N. For severe tropical storms, typhoons, severe typhoons, and super typhoons, their average decaying rates are all greater than the respective average growing rates; for tropical storms, however, the average decaying rate is smaller than the average growing rate. Generally speaking, the stronger the TC, the faster the intensification （weakening） is. The percentage of weak TCs is higher in June to August while that of strong TCs is higher in September to November. There are annual, interannual, and interdecadal variations in the observed number （every 6 h） and frequency of TCs at different intensity scales. As far as the long-term trend is concerned, the frequency and observed number of tropical storms have a significant linear increase, but the averaged intensity and number of TCs of other intensity categories do not exhibit such a significant linear trend. In E1 Nifio years, the number and percentage of super typhoons are significantly higher, while the total number of tropical storms, severe tropical storms, typhoons, and severe typhoons is significantly lower, and the mean intensity of TCs is prominently stronger; in La Nifia years, however, the opposite comes true.