闪电活动的气候学特征研究进展

综述了闪电活动与气候和气候变化相关研究的一系列最新进展。这些研究表明全球闪电活动可以通过卫星光学方法、地面的单站舒曼共振法以及低频多站时差法进行观测,其结果指出全球闪电密度高值区主要分布在海岸地区、山地地区、中尺度气旋多发地区以及热带辐合带的辐合区内,大陆、海岛、沿海地区所发生的闪电占全球的88%,全球3个闪电密度极大值依次出现在赤道地区的非洲刚果、南美洲大陆和东南亚。大量的研究结果表明全球闪电活动是与气候和气候变化相关的,在日、5d、季、半年、年、ENSO、10a多个时间尺度上,闪电活动对温度做出了一定的正响应,但在更长时间尺度上这种敏感性似乎是减弱的。闪电活动因易于被持续监测而可以作为监测气候一些重要参数变化的有利工具。闪电活动是氮氧化物(NOx)的重要产生源,这与臭氧等温室气体以及地球辐射之间存在密切关系。在短时间尺度上,对流层上层水汽和全球闪电活动之间存在非常好的相关性。气溶胶对雷暴以及闪电活动的影响还不明确。气候变化与雷暴和闪电活动之间的相互耦合机制还有待于更多的观测和深入的研究。     

Lightning and climate: A review

Research on regional and global lightning activity and the global electrical circuit is summarized. This area of activity has greatly expanded through observations of lightning by satellite and through increased use of the natural (Schumann) resonances of the Earth–ionosphere cavity. The global electrical circuit provides a natural framework for monitoring global change on many time scales. Lightning is responsive to temperature on many time scales, but the sensitivity to temperature appears to diminish at the longer time scales.     

基于卫星遥感的植被NDVI对气候变化响应的研究进展

回顾了以往植被对气候响应的有关研究,从此类研究常使用的数据、方法及获取的结论3个方面进行了分析,重点阐述了归一化植被指数（Normalized Difference Vegetation Index,NDVI）对降水、温度和辐射等气候因子的响应特征,并探讨了未来的发展趋势。结果表明,植被NDVI对降水的显著响应往往出现在干旱半干旱地区和干湿季气候差异明显地区,且具有一定的滞后特征,滞后的时间尺度与局地条件关系密切;温度成为植被NDVI 控制因子的情况常出现在温带或寒温带地区,与对降水的滞后响应相比,植被对于温度的滞后响应并不是特别明显;辐射对于植被的主导影响主要出现在低纬度的部分区域、高云量区域和高纬度地区的特定时间段内。认为量化人类在植被对气候变化响应过程中的作用,全球变暖情形下植被对气候响应特征的深入分析,以及植被受气候影响的多尺度特征可能是以后此类研究的发展方向。     

全球闪电活动与气候变化

全球闪电活动与气候变化关系的研究正受到越来越多的重视,该文从卫星上观测到的全球闪电活动、闪电活动和全球电路对温度的响应,闪电和对流层上部水汽的联系,闪电和N0,等几方面进行了阐述,指出了闪电活动在气候变化研究中的重要性。同时,文中还对影响闪电活动和起电过程的热力动力作用以及气溶胶的作用等进行了分析。     

Will a drier climate result in more lightning?

With recent projections of a warmer climate in the future, one of the key questions is related to the impact of global warming on thunderstorms, and severe weather. Will lightning activity increase in a warmer world? Since the majority of global lightning activity occurs in the tropics, changes in future global lightning activity will depend on changes in the tropical climate. The latest IPCC [Intergovernmental Panel on Climate Change (IPCC). 2007] projections show a partial drying out of the tropical landmasses as the global climate gets warmer. This is caused by both changes in rainfall patterns, but also due to increases in evapo-transpiration. We would expect a drier climate to produce fewer thunderstorms, and less lightning. However, experimental and modeling studies have shown that as tropical regions dry in the present climate, they experience greater lightning activity. This paradox may be explained by noting that while drier climate conditions result in fewer thunderstorms and less rainfall, the thunderstorms that do occur are more explosive, resulting in more lightning activity.     

气候变化背景下陆地季风与非季风区极端降水特征对比

利用月平均地表气候要素数据集(CRUTS 4.02)的逐月降水和逐月日平均气温资料,采用线性趋势分析、滑动平均和相关分析等方法,研究了 1901-2017年气候变化背景下全球陆地季风区与非季风区的极端降水特征.结果表明:我国所处的亚洲季风区的极端降水频率分布较为稳定,仅在变暖减缓时段出现大范围小值区;非季风区在急剧加速...     

Quantifying Changes in Extreme Weather Events in Response to Warmer Global Temperature

Global warming is expected to affect both the frequency and severity of extreme weather events, though projections of the response of these events to climate warming remain highly uncertain. The range of changes reported in the climate modelling literature is very large, sometimes leading to contradictory results for a given extreme weather event. Much of this uncertainty stems from the incomplete understanding of the physics of extreme weather processes, the lack of representation of mesoscale processes in coarse-resolution climate models, and the effect of natural climate variability at multi-decadal time scales. However, some of the spread in results originates simply from the variety of scenarios for future climate change used to drive climate model simulations, which hampers the ability to make generalizations about predicted changes in extreme weather events. In this study, we present a meta-analysis of the literature on projected future extreme weather events in order to quantify expected changes in weather extremes as a function of a common metric of global mean temperature increases. We find that many extreme weather events are likely to be significantly affected by global warming. In particular, our analysis indicates that the overall frequency of global tropical cyclones could decrease with global warming but that the intensity of these storms, as well as the frequency of the most intense cyclones could increase, particularly in the northwestern Pacific basin. We also found increases in the intensity of South Asian monsoonal rainfall, the frequency of global heavy precipitation events, the number of North American severe thunderstorm days, North American drought conditions, and European heatwaves, with rising global mean temperatures. In addition, the periodicity of the El Niño–Southern Oscillation may decrease, which could, in itself, influence extreme weather frequency in many areas of the climate system.     

我国地闪活动和降水关系的区域差异

利用我国部分地区2005年的地闪定位资料和气象台站雨量观测资料,由南向北选取我国四个不同气候带区域(区域1～4),分析了这些区域的地闪活动与降水的相关关系。结果表明,由南向北及气候特征由潮湿趋于干旱的区域的地闪活动和降水相关性增强。闪电活动与有闪电降水(即对应闪电的降水)日变化的线性相关系数在由南向北的区域分别为0.56、0.46、0.56、0.80,旬变化的线性相关系数分别为0.73、0.86、0.89、0.92,月变化的线性相关系数分别为0.74、0.88、0.965、0.99;较干旱的区域3和区域4的地闪活动与所有降水的时间序列有较强的相关性,其线性相关系数日变化分别为0.31、0.41,旬变化分别为0.84,0.52,月变化分别为0.93、0.80;地闪与降水的空间线性关系相对复杂,但也表现出由南向北和气候趋于干旱对应关系增强的特征,区域4的闪电和降水相关性达到0.54。分析区域中较干旱地区的雷暴活动产生机制(主要受热力抬升作用)相比潮湿地区(既受热力抬升作用,又受大尺度系统相互作用)更为单一,这可能是干旱地区的闪电活动与降水有较好相关的重要原因。     

卫星观测的我国近海海域闪电分布特征

利用星载闪电探测仪OTD(optical transient detecter)和LIS(lightning imaging sensor)所获取的1995年6月—2006年4月的卫星闪电资料,结合NOAA Optimum Interpolation SST海温资料,分析我国近海海域的闪电分布时空特征以及闪电活动与该海域海温之间的相关性。结果表明:我国近海闪电密度平均值为3.39 fl·km~(-2)·a~(-1),其中,南海和渤海的闪电活动相对频繁,随着与海岸线间距离以及纬度的增加,该海域闪电密度逐渐下降;在春季和冬季,黑潮主干海域的海温值相对较高,该处闪电活动也明显强于同纬度的东海近海和太平洋海域,表明黑潮海域是强闪电活动区;在季节变化上,我国近海海域闪电活动与同海域海温呈明显正相关,相关系数达0.797,闪电活动与海温变化体现出了一致的变化趋势;而在年际变化上,我国近海海域闪电活动与该海域海温的线性相关不显著,说明我国近海海域海温的年际变化并不是引起该海域闪电活动年际变化的主要原因。     

中国地表月平均反照率的遥感反演

地表特征和下垫面物理性质在时空分布上的差异 ,造成地表能量分布的不均 ,地球表面的半球反射在气候领域是一个非常重要的参数 ,它在地 气能量交换中决定着能量在地 气之间的分配比率。反照率随地表覆盖类型的变化具有很大的差异 ,而这往往是形成区域小气候差异的原因。文中通过统计和双向反射模型 ,应用NOAA14 AVHRR数据并结合地理信息系统 ,反演计算了 1997年中国月平均反照率的分布 ,并对结果做了分析检验。     

On the relation between ENSO and global climate change

Summary Two lines of research into climate change and El Niño/Southern Oscillation (ENSO) converge on the conclusion that changes in ENSO statistics occur as a response to global climate (temperature) fluctuations. One approach focuses on the statistics of temperature fluctuations interpreted within the framework of random walks. The second is based on the discovery of correlation between the recurrence frequency of El Niño and temperature change, while developing physical arguments to explain several phenomena associated with changes in El Niño frequency. Consideration of both perspectives leads to greater confidence in, and guidance for, the physical interpretation of the relationship between ENSO and global climate change. Topics considered include global dynamics of ENSO, ENSO triggers, and climate prediction and predictability.Revised November 14, 2002; accepted November 28, 2002 Published online: June 12, 2003     

Climatic Changes in Thermal Conditions of Marginal Seas in the Western Pacific

Observational data from the Roshydromet hydrometeorological stations for 1978–2017, global meteorological network, and objective analysis and reanalysis (NOAA) are used to study the interannual variability of sea surface temperature and air temperature in the coastal and marine areas of the Okhotsk, Japan, Yellow, East China, and South China seas at the modern stage of the warming. Based on the EOF, cluster, and correlation analysis, the spatiotemporal pattern of temperature variations is analyzed and the zoning of sea areas according to the features of modern climate change is performed. The possible cause-and-effect relationships between these changes and the variations in wind components and climate indices are investigated. The studies revealed, specified, and quantified the modern trends and regional features of interannual variability of thermal conditions in the distinguished areas.     

上海气温与太平洋海温的相关关系及年代际差异

利用上海1873—2001年的冬、夏季平均温度和太平洋海温资料，通过计算两者之间的同期和超前相关以及滑动相关系数，讨论了上海冬（夏）季温度与太平洋海温场相关关系的年代际差异。结果发现，上海冬（夏）季温度存在明显的年代际变化的阶段性特征和总体增暖的趋势，而且与太平洋海温场在不同时间尺度和空间区域的相关关系差异显著，这种相关关系的差异可能是造成用统计方法做短期气候预测产生不确定性的主要原因之一，因此应用太平洋海温场进行统计预报的过程中，适当考虑不同时间尺度上的相关差异，将有利于提高预测的准确性和减少统计预测方法中的不确定性。     

MM5 Simulations of the China Regional Climate During the LGM.Ⅰ: Influence of CO2 and Earth Orbit Change

Using a regional climate model MM5 nested to an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate the relative Last Glacial Maximum (LGM) climate response to different mechanisms over China. Model simulations of the present day (PD) climate and the LGM climate change are in good agreement with the observation data and geological records, especially in the simulation of precipitation change. Under the PD and LGM climate, changes of earth orbital parameters have a small influence on the annual mean temperature over China.However, the magnitude of the effect shows a seasonal pattern, with a significant response in winter. Thus,this influence cannot be neglected. During the LGM, CO2 concentration reached its lowest point to 200 ppmv. This results in a temperature decrease over China. The influences of CO2 concentration on climate show seasonal and regional patterns as well, with a significant influence in winter. On the contrary, CO2concentration has less impact in summer season. In some cases, temperature even increases with decreasing in CO2 concentration. This temperature increase is the outcome of decrease in cloud amount; hence increase the solar radiation that reached the earth's surface. This result suggests that cloud amount plays a very important role in climate change and could direct the response patterns of some climate variables such as temperature during certain periods and over certain regions. In the Tibetan Plateau, the temperature responses to changes of the above two factors are generally weaker than those in other regions because the cloud amount in this area is generally more than in the other areas. Relative to the current climate, changes in orbital parameters have less impact on the LGM climate than changes in CO2 concentration. However,both factors have rather less contributions to the climate change in the LGM. About 3%-10% changes in the annual mean temperature are contributed by CO2.     

MM5 Simulations of the China Regional Climate During the LGM.I: In uence of CO2 and Earth Orbit Change

Using a regional climate model MM5 nested to an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate the relative Last Glacial Maximum (LGM) climate response to different mechanisms over China. Model simulations of the present day (PD) climate and the LGM climate change are in good agreement with the observation data and geological records, especially in the simulation of precipitation change. Under the PD and LGM climate,changes of earth orbital parameters have a small influence on the annual mean temperature over China.However, the magnitude of the effect shows a seasonal pattern, with a significant response in winter. Thus,this influence cannot be neglected. During the LGM, CO2 concentration reached its lowest point to 200 ppmv. This results in a temperature decrease over China. The influences of CO2 concentration on climate show seasonal and regional patterns as well, with a signi cant influence in winter. On the contrary, CO2 concentration has less impact in summer season. In some cases, temperature even increases with decreasing in CO2 concentration. This temperature increase is the outcome of decrease in cloud amount; hence increase the solar radiation that reached the earth's surface. This result suggests that cloud amount plays a very important role in climate change and could direct the response patterns of some climate variables such as temperature during certain periods and over certain regions. In the Tibetan Plateau, the temperature responses to changes of the above two factors are generally weaker than those in other regions because the cloud amount in this area is generally more than in the other areas. Relative to the current climate, changes in orbital parameters have less impact on the LGM climate than changes in CO2 concentration. However,both factors have rather less contributions to the climate change in the LGM. About 3%-10% changes in the annual mean temperature are contributed by CO2.     

Assessing the strength of regional changes in near-surface climate associated with a global warming of 2°C

In this study, the strength of the regional changes in near-surface climate associated with a global warming of 2°C with respect to pre-industrial times is assessed, distinguishing between 26 different regions. Also, the strength of these regional climate changes is compared to the strength of the respective changes associated with a markedly stronger global warming of 4.5°C. The magnitude of the regional changes in climate is estimated by means of a normalized regional climate change index, which considers changes in the mean as well as changes in the interannual variability of both near-surface temperature and precipitation. The study is based on two sets of four ensemble simulations with the ECHAM5/MPI-OM coupled climate model, each starting from different initial conditions. In one set of simulations (1860–2200), the greenhouse gas concentrations and sulphate aerosol load have been prescribed according to observations until 2000 and according to the SRES A1B scenario after 2000. In the other set of simulations (2020–2200), the greenhouse gas concentrations and sulphate aerosol load have been prescribed in such a way that the simulated global warming does not exceed 2°C with respect to pre-industrial times. The study reveals the strongest changes in near-surface climate in the same regions for both scenarios, i.e., the Sahara, Northern Australia, Southern Australia and Amazonia. The regions with the weakest changes in near-surface climate, on the other hand, vary somewhat between the two scenarios except for Western North America and Southern South America, where both scenarios show rather weak changes. The comparison between the magnitude of the regional changes in near-surface climate for the two scenarios reveals relatively strong changes in the 2°C-stabilization scenario at high northern latitudes, i.e., Northeastern Europe, Alaska and Greenland, and in Amazonia. Relatively weak regional climate changes in this scenario, on the other hand, are found for Eastern Asia, Central America, Central South America and Southern South America. The ratios between the regional changes in the near-surface climate for the two scenarios vary considerably between different regions. This illustrates a limitation of obtaining regional changes in near-surface climate associated with a particular scenario by means of scaling the regional changes obtained from a widely used “standard” scenario with the ratio of the changes in the global mean temperature projected by these two scenarios.     

Water Resources of the South Asian Region in a Warmer Atmosphere

The global mean surface temperature may rise by about 0.3oC per decade during the next Few decades as a result of anthropogenic greenhouse gas emissions in the earth’s atmosphere. The data generated in the greenhouse warming simulations (Business-as-Usual scenario of IPCC) with the climate models developed at Max Planck Institute for Meteorology, Hamburg have been used to assess future plausible hydrological scenario for the South Asian region. The model results indicate enhanced surface warming (2.7oC for summer and 3.6oC for winter) over the land regions of South Asia during the next hundred years. While there is no significant change in the precipitation over most of the land regions during winter, substantial increase in precipitation is likely to occur during summer. As a result, an increase in soil moisture is likely over central India, Bangladesh and South China during summer but a statistically sig-nificant decline in soil moisture is expected over central China in winter. A moderate decrease in surface runoff may occur over large areas of central China during winter while the flood prone areas of NE-India. Bangladesh and South China are likely to have an increase in surface runoff during summer by the end of next century.     

低纬高原地区短时强降水与雷电活动相关性研究

为了研究短时强降水过程与雷电活动过程的相关性,统计了 2012-2016年云南省126个国家级气象站的短时强降水次数和降水量,以及强降水时段内、强降水前1小时站点周边50公里、30公里、10公里半径范围内的地闪次数.运用概率统计理论分析强降水过程发生时、过程前1小时周边不同尺度范围内地闪发生的概率.同时应用相关回归方法...     

从全球到区域气候变化

尽管气候变化是全球性的现象,但其表现和结果随区域不同而不同,因此区域气候信息对于气候变化的作用和风险评估很重要.基于此,IPCC第六次评估报告(AR6)第一工作组(WGI)报告第十章对如何从全球链接到区域气候变化方面进行了评估.区域气候变化是对自然强迫和人类活动的区域响应、对大尺度气候系统内部变率的响应和区域气候本身反...     

北京地区雷暴过程闪电与地面降水的相关关系

该文选取北京地区2006年夏季的18次雷暴过程,利用SAFIR3000三维闪电定位系统观测到的总闪数据,分析了闪电与雷达反演的对流活动区降水量和对流活动区面积的相关关系,结果表明:北京地区的雷暴活动中,单个闪电所表征的降水量的范围在0.86×10~7～6.57×10~7kg/fl之间,平均值为2.65×10~7kg/fl;闪电活动与对流活动区降水量的线性相关关系显著,相关系数达到0.826;闪电活动与对流活动区面积也具有显著的线性关系,相关性系数达到0.846。文中给出了基于6 min闪电频次估算6 min对流降水量以及对流活动区面积的拟合方程。分析还发现,总闪活动与降水的关系要明显好于地闪,总闪信息的应用极大提高了分析结果的质量和可信性,分析结果对于利用闪电信息估测降水具有参考意义。