广州高建筑物雷电观测与研究10年进展

作为中国气象局雷电野外科学试验基地(CMA_FEBLS)的重要组成部分,广州高建筑物雷电观测站(TOLOG)始建于2009年,迄今已积累数百次高建筑物雷电资料。对于雷电连接过程,高建筑物会起到“放大镜”的作用：TOLOG的观测在国际上首次发现了连接过程中负-正先导之间“头部-侧面”连接的现象,给出了先导连接行为的两种基本形态;揭示了负先导梯级发展过程的精细化结构,给出了下行先导和上行先导的二维/三维发展特征;估算了不同高度建筑物上雷电的闪击距离。高建筑物对雷电电磁场具有“放大器”的作用,且建筑物越高增强效应越显著。高建筑物是下行和上行闪电的“汇集点”：对下行闪电的吸引作用可保护高建筑物附近的其他物体免遭雷击;正地闪的回击、延续电流和云内放电过程均可在高建筑物上触发负极性上行闪电。另外,高建筑物区域可作为闪电监测系统的“标校场”,TOLOG的观测资料在地闪定位系统探测效率和定位精度的评估方面也得到了应用。     

近十年数值天气预报的回顾和展望

对近十年来数值天气预报总的趋势,以及在业务预报、模式和模式设计、物理过程、资料四维同化和有关计算方法等方面的进展进行了评述,并指出了其中存在的问题,作了展望。     

A review of advances in lightning observations during the past decade in Guangdong,China

This paper reviews recent advances in understanding the physical processes of artificially triggered lightning and natural lightning as well as the progress in testing lightning protection technologies, based on a series of lightning field campaigns jointly conducted by the Chinese Academy of Meteorological Sciences and Guangdong Meteorological Bureau since 2006. During the decade-long series of lightning field experiments, the technology of rocket-wire artificially triggered lightning has been improved, and has successfully triggered 94 lightning flashes. Through direct lightning current waveform measurements, an average return stroke peak current of 16 kA was obtained. The phenomenon that the downward leader connects to the lateral surface of the upward leader in the attachment process was discovered, and the speed of the upward leader during the connection process being significantly greater than that of the downward leader was revealed. The characteristics of several return strokes in cloud-to-ground lighting have also been unveiled, and the mechanism causing damage to lightning protection devices (i.e., ground potential rise within the rated current) was established. The performance of three lightning monitoring systems in Guangdong Province has also been quantitatively assessed.     

全球雷电活动研究进展

雷电是发生在大气圈中伴随雷暴天气出现的一种瞬时高电压、大电流、强电磁辐射的灾害性天气现象。雷电活动对航空、航天、石油、化工、通讯等关系着国计民生的行业有着重要影响,因此越来越受到人们的关注。本文是关于近年来全球雷电专家对雷电活动研究成果的总结与归纳,主要是对雷电活动的探测手段、全球雷电活动特征、各种天气背景条件下（台风及中尺度对流系统等）雷电活动特征、雷电活动对气候变化的响应与影响等方面的研究进展,尽量完整及时的呈现出学界对雷电活动的最新研究进展。     

卫星观测的西南地区闪电的时空分布

利用TRMM卫星上携带的闪电探测仪（LIS）所获取的10 a闪电资料（1998—2007年）对西南地区闪电活动的时空分布特征进行了分析。结果表明：该地区闪电次数的年差异较大,最多年份是最少年份的2倍多,闪电活动季节性特征非常明显,闪电主要集中在春末仲夏发生,呈现单峰值特征,4—8月是闪电高发期（约占全年总闪电活动的84.83%）。闪电活动的日变化表明,闪电峰值区集中在傍晚、午夜前后两个时段,闪电谷值区出现在09：00—12：00,夜雷暴多,这是与其他地区闪电日变化显著不同的地方。在对闪电次数进行了探测效率订正后,根据LIS注视时间,计算了闪电密度。西南地区闪电密度分布大体呈现：东部高,西部低;南部高,北部低。闪电密度较高、面积较大的高值中心位于中越交界的老山一带,非常明显的大片低发区主要位于西南西部地区。研究表明：西南地区闪电时空分布与当地的地形地势、水汽和地理环境条件等诸多因素有关。     

Seasonal Forecast of South China Sea Summer Monsoon Onset Disturbed by Cold Tongue La Niña in the Past Decade

It has been suggested that a warm(cold)ENSO event in winter is mostly followed by a late(early)onset of the South China Sea(SCS)summer monsoon(SCSSM)in spring.Our results show this positive relationship,which is mainly determined by their phase correlation,has been broken under recent rapid global warming since 2011,due to the disturbance of cold tongue(CT)La Ni?a events.Different from its canonical counterpart,a CT La Ni?a event is characterized by surface meridional wind divergences in the central-eastern equatorial Pacific,which can delay the SCSSM onset by enhanced convections in the warming Indian Ocean and the western subtropical Pacific.Owing to the increased Indian?western Pacific warming and the prevalent CT La Ni?a events,empirical seasonal forecasting of SCSSM onset based on ENSO may be challenged in the future.     

Recent Advances in Research of Lightning Meteorology

Lightning meteorology focuses on investigating the lightning activities in different types of convective weather systems and the relationship of lightning to the dynamic and microphysical processes in thunder- storms. With the development and application of advanced lightning detection and location technologies, lightning meteorology has been developed into an important interdiscipline between atmospheric electricity and meteorology. This paper mainly reviews the advances of lightning meteorology research in recent years in China from the following five aspects： 1） development of advanced lightning location technology, 2） char- acteristics of lightning activity in different convective systems, 3） relationship of lightning to the dynamic and microphysical processes in thunderstorms, 4） charge structure of thunderstorms, and 5） lightning data assimilation techniques and application to severe weather forecasting. In addition, some important aspects on future research of the lightning meteorology are proposed.     

Strengthened Regulation of the Onset of the South China Sea Summer Monsoon by the Northwest Indian Ocean Warming in the Past Decade

Traditionally,a delayed(early)onset of the South China Sea summer monsoon(SCSSM)has been observed to follow a warm(cold)El Ni?o-Southern Oscillation(ENSO)event in winter,supporting high seasonal predictability of SCSSM onset.However,the empirical seasonal forecasting skill of the SCSSM onset,solely based on ENSO,has deteriorated since 2010.Meanwhile,unexpected delayed onsets of the SCSSM have also occurred in the past decade.We attribute these changes to the Northwest Indian Ocean(NWIO)warming of the sea surface.The NWIO warming has teleconnections related to(1)suppressing the seasonal convection over the South China Sea,which weakens the impacts of ENSO on SCSSM onset and delays the start of SCSSM,and(2)favoring more high-frequency,propagating moist convective activities,which enhances the uncertainty of the seasonal prediction of SCSSM onset date.Our results yield insight into the predictability of the SCSSM onset under the context of uneven ocean warming operating within the larger-scale background state of global climate change.     

雷电监测预警预报技术简述

从监测、预警和预报3个方面介绍了雷电研究的技术方法,目前国内外最新面向业务应用的研究表明:不同技术共存的多源化观测设备,有效地提高了雷电探测效率;以天气形势分型为主的雷电潜势预报,其预报结果具有很大的不确定性,且其预报精细化程度不够,引入适合本地的物理量参数实现对其结果校准,可以有效地提高雷电潜势预报的准确率;随着数值模式预报向全球化、精细化的发展,基于数值模式的雷电潜势预报是未来的一个重点发展方向;建立在多种高观测频次资料融合和有效外推基础上的临近预报,可提高雷电活动预警预报的准确性,大幅提高雷电预警的提前时间。     

Enhancement of Winter Arctic Warming by the Siberian High over the Past Decade

In recent decades the Arctic surface air temperature(SAT) in autumn has been increasing steadily. In winter, however, instead of a linear trend, the Arctic SAT shows an abrupt change that occurred in 2004. During the years from 1979 to 2003, the first principle component(PC1) of winter Arctic SAT remains stable, and no significant increasing trend is detected. However, the PC1 changes abruptly from negative to positive phase in the winter of 2004. The enhanced Siberian high may have contributed to this abrupt change because the temporal evolution of Arctic temperature correlates significantly with sea level pressure variation in the northern Eurasian continent, and the atmospheric circulation anomaly related to the Siberian high from 2004 to 2013 favors a warmer Arctic. With the help of the meridional wind anomaly around the Siberian high, warmer air is transported to the high latitudes and therefore increases the Arctic temperature.     

近10a西北太平洋海域登陆台风的环境场特征分析

对1995~2004年5~10月西北太平洋海域登陆台风的大尺度环境场的特征进行了分析。结果表明:海表温度(SST)在台风发生的区域要高于周围其它区域,而且都在26.5℃以上,即高的海表温度有利于台风的发展;在台风的发现点主要集中的区域范围,相对涡度几乎都为正值,正的相对涡度有利于台风的发展;对流层中层相对湿度大,有利于上升浮力和潜热释放的维持,使热带气旋得以发展;弱的环境风垂直切变有利于台风强度的增大,并且两者之间的影响存在着一定的时间滞后。     

近10a西北太平洋海域登陆台风的环境场特征分析

对1995～2004年5～10月西北太平洋海域登陆台风的大尺度环境场的特征进行了分析。结果表明：海表温度（SST）在台风发生的区域要高于周围其它区域,而且都在26.5℃以上,即高的海表温度有利于台风的发展;在台风的发现点主要集中的区域范围,相对涡度几乎都为正值,正的相对涡度有利于台风的发展;对流层中层相对湿度大,有利于上升浮力和潜热释放的维持,使热带气旋得以发展;弱的环境风垂直切变有利于台风强度的增大,并且两者之间的影响存在着一定的时间滞后。     

Optical Observations on Propagation Characteristics of Leaders in Cloud-to-Ground Lightning Flashes

Using 2 high-speed cameras, we have recorded 14 negative cloud-to-ground (CG) lightning flashes, half of which are natural and the others are artificially triggered. The two-dimensional (2D) propagation speed of different type leaders and the luminosity of lightning channel are analyzed in detail. Bidirectional leader processes are observed during the initial processes of two altitude triggered negative lightning (ATNL)flashes. The analysis shows: the propagation speed of the upward positive leader (UPL) before the initiation of the downward negative leader (DNL) is at the order of 104-105 m s-1; the UPL can be intensified by the initiation and development of the DNL in the way that the luminosity is enhanced and the speed is sped up; after initiation, the DNL in one ATNL flash propagates downward three times intermittently with interval of about 1 ms, while that in the other ATNL flash propagates downward continuously with a speed at the order of 105 m s-1. In the five classical triggered negative lightning (CTNL) flashes, the propagation speeds of the UPLs vary between 0.35×105 and 7.71×105 m s-1, and the variations of their luminosities and speeds are quite complex during the development processes. Among the four observed natural negative lightning flashes occurred on the land, three have only one return stoke (RS) each and all of their DNLs have many branches with an average speed at the order of 105 m s-1; while the another one has 13 RSs.In the CG flash with 13 RSs, the DNL before the first RS has no obvious branch below 1.4 km above the ground, and its speed ranges from 2.2×105 to 2.3×105 m s-1 between the heights of 0.7 and 1.4 km and exceeds 3.9×106 m s-1 below 0.7 km; preceding the 4th RS, an attempted leader is observed with a speed ranging from 1.1×105 to 1.1×106 m s-1 between 0.8 and 1.5 km. As for the three observed natural negative lightning flashes occurred on the sea, each has only one RS, and each DNL preceding the RS has a few branches, two of which have an average propagation speed at the order of 105 m s-1, and the other of 106m s-1, respectively. All the DNLs contained in the observed natural negative lightning flashes, except the attempted leader, propagate with gradually increasing luminosity and increasing speed in whole.     

上海市两套闪电定位系统探测能力对比分析

为综合评价上海市两套闪电定位系统(Vaisala和Earth Network Total Lightning System)对上海及周边地区地闪的探测能力,利用2015 2016年两套闪电定位系统数据,从地闪数据量、雷电强度、时空分布、空间匹配度和定位精度等多个方面展开对比。结果表明,在上海市范围内相同时间段内Vaisala探测到的地闪频次稳定大于Entls的,但在上海市区域外则相反。两套系统探测到地闪雷电流强度呈单峰分布,以10~20 k A区间内的雷电居多。从数据空间匹配度来看,上海北部地区及杭州湾南岸,Entls相对Vaisala地闪探测的匹配度达70%以上,在上海市范围内该匹配度降至20%左右。两套系统探测到的地闪定位误差大部分集中在5 km以内,且以0~2 km为主。雷暴过程中两套系统探测的地闪随时间变化趋势较为一致,且与雷达回波有一定的匹配度。因此,两套系统都能实现对上海及周边地区地闪的探测,但由于设备型号、探测技术和自身误差等方面的差异,数据量上有差异,需要长时间积累数据进行对比分析,才能更好地利用数据,为防雷减灾服务。     

中国雷电活动特征分析

雷电活动资料在国民经济和国防建设中涉及防雷减灾问题上有重要的应用价值,本文对中国672个地面站点1961～2006年的雷暴日资料进行处理分析,同时利用星载闪电探测器(OTD/LISOptical Tran Sient Detector/Lightning Imaging Sensor)的闪电观测资料集(1995～2005年),对中国雷电活动的时空特征进行了再分析,得到以下结果①中国雷暴活动的时空分布;②闪电密度和雷暴日在中国的空间分布存在差异性;③中国和中国不同地区闪电活动的年变化和日变化特征;④中国不同地区包括各省、直辖市、自治区闪电密度的各种特征.     

东北地区降水日数、强度和持续时间的年代际变化

利用93站1951—2002年逐日降水资料,分析了东北地区不同强度降水事件的时空演变特征及其对旱涝的影响。结果表明：52年来,东北地区小雨事件对年降水量的贡献率呈显著增加趋势,中雨的贡献率略为减少,大雨和暴雨的贡献率变化不大;东北年总雨日减少趋势非常明显,雨日的减少主要体现在小雨日数的减少;年降水强度表现为明显的增强趋势,主要体现为小雨和暴雨强度增强;20世纪80年代中期之前多小雨事件,80年代中期之后多中雨以上强度的降水,特别是90年代中期之后多暴雨事件。在显著变暖的20世纪90年代,降水日数明显减少,但暴雨日数基本不变,强度明显增强。对东北地区降水量、降水变幅、降水事件的变化特征分析表明：该区域降水有向不均衡、极端化发展的趋势,旱涝灾害也有加重趋势。     

我国热带气旋研究十年进展

90年代初,国内外开展了几次大规模的热带气旋现场试验,取得了许多宝贵的加 密观测资料。利用这些资料,对热带气旋尤其是异常热带气旋开展了一系列的研究。我国科学家在国家科技攻关85-906项目中的“台风科学、业务试验和天气动力学理论的研究”等与热带气旋有关的课题和国际热带气旋研究合作项目“SPECTRUM(SpecialExperimentConcerningTyphoonRecurvatureandUnusualMovement)”中对台风的突变现象和预报技术进行了重点研究。从而在过去10年中,在台风运动突变、结构和强度突变、台风暴雨的突然增幅、热带气旋路径预报方法研究等方面都取得了新的进展。作者将对这些进展作简要综述。     

世界各国静止气象卫星发展综述

首先阐述了美国、欧洲气象卫星组织(EUMETSAT)、日本静止气象卫星的发展历史,从自旋稳定到三轴稳定,从单一载荷到多载荷并行工作,新一代的静止气象卫星的时间、空间和光谱分辨率都大幅提高,然后重点介绍了我国静止气象卫星风云二号和风云四号,相比于自旋稳定的风云二号气象卫星,风云四号卫星的功能和性能实现了跨越式的发展,接着简单介绍了俄罗斯、印度和韩国等其他国家静止气象卫星的发展状况,最后总结了不同时期各国静止气象卫星的发展特点,这对我国后续静止气象卫星的规划和研制有重要参考意义。     

国际行业温室气体减排方法最新进展评述

由于《巴厘行动计划》中明确提出"合作的行业方法"以及发达国家的积极推动,所谓国际行业减排方法正受到越来越多的关注。在对此类方法的定义、分类和提出背景进行简要介绍的基础上,总结了该类方法的最新进展和发展动向。最后对近期发展的特点进行了归纳与评述,指出了发展中国家尤其是我国在国家和行业发展层面所面临的挑战和亟待解决的问题。     

中国近50a来度日变化的研究

采用中国1951—2006年的气象观测资料,在运用度日分析法分析全国、各省及省会城市近50 a的平均温度变化的基础上,系统分析全国的度日变化情况;研究了中国六大区省会城市热度日（Heating Degree-day,HDD）和冷度日（Cooling Degree-day,CDD）的变化情况;分析了典型城市北京、上海、广州CDD的上升趋势和上升率,并求得相关方程。结果表明,北京、上海、广州CDD的长期变化都呈上升趋势,上升率分别为11.7℃/（10 a）、10.4℃/（10 a）、25.1℃/（10 a）。