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1.
ZHAO Tian-Bao 《大气和海洋科学快报》2014,(4):369-375
Diurnal temperature range （DTR） is an im- portant measure in studies of climate change and variability. The changes of DTR in different regions are affected by many different factors. In this study, the degree of correlation between the DTR and atmospheric precipitable water （PW） over China is explored using newly homogenized surface weather and sounding observations. The results show that PW changes broadly reflect the geographic patterns of DTR long-term trends over most of China during the period 1970-2012, with significant anticorrelations of trend patterns between the DTR and PW, especially over those regions with higher magnitude DTR trends. PW can largely explain about 40% or more （re 0.40） of the DTR changes, with a d（PW）/d（DTR） slope of -2% to -10% K^-1 over most of northwestern and southeastern China, despite certain seasonal dependencies. For China as whole, the significant anticorrelations between the DTR and PW anomalies range from -0.42 to -0.75, with a d（PW）/d（DTR） slope of-6% to -11% K^-1. This implies that long-term DTR changes are likely to be associated with opposite PW changes, approximately following the Clausius-Clapeyron equation. Furthermore, the relationship is more significant in the warm season than in the cold season. Thus, it is possible that PW can be considered as one potential factor when exploring long-term DTR changes over China. It should be noted that the present study has a largely statistical focus and that the underlying physical processes should therefore be examined in future work. 相似文献
2.
2007年6月27日上午10：30左右,沧州市出现强雷雨天气过程。沧州供电公司2条高压线路被雷电击断,造成2人死亡的事故。 相似文献
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根据湖北省雷电定位系统（Lightning Location System,LLS）2007年1月1日至2016年12月31日监测资料,采用数理统计方法,对湖泊和陆地区域的地闪频次、极性、地闪密度、雷电流幅值和波头陡度等雷电参数分布特征进行了对比研究。结果表明：湖泊与陆地的雷电参数时间变化趋势基本一致。近10 a闪电频次呈明显减少趋势,正地闪比例呈上升趋势;陆地比湖泊区域的闪电频次多,春夏季湖泊和陆地闪电频次差异明显,其中,夏季陆地闪电频次比湖泊多21.1%;湖泊和陆地闪电频次日变化大致呈单峰型,13-18时陆地闪电频次比湖泊多39.7%。湖泊地闪密度比陆地小,湖泊和陆地平均地闪密度分别为2.96次·（km-2·a-1）和3.47次·（km-2·a-1）。湖泊的平均雷电流幅值较陆地大;湖泊和陆地的平均雷电流波头陡度变化不大,相差一般在1 kA·（μs）-1以下。 相似文献
5.
Kathrin Wapler 《Meteorology and Atmospheric Physics》2013,122(3-4):175-184
A 6-year analysis (including data of 36 million strokes) of the spatial and temporal occurrence of lightning strokes in Germany and neighbouring areas is presented. The analysis on a high-resolution grid with spatial resolution of 1 km allows assessing the local risk of lightning and studying local effects, e.g. the influence of orography on the occurrence of thunderstorms. The analysis reveals spatial and temporal patterns: the highest number of lightning strokes occurs in the pre-alpine region of southern Germany, further local maxima exists in low mountain ranges. The lowest number of lightning strokes is present in areas of the North Sea and Baltic Sea. Despite a high year-to-year variability of lightning rates, on average a clear annual cycle (maximum June to August) and diurnal cycle (maximum in the afternoon) are present. In addition to this well-known annual and diurnal pattern, the analysis shows that those are intertwined: the diurnal cycle has an annual cycle, visible in the time of daily maximum which occurs later in the afternoon in summer compared to spring and autumn. Furthermore, the annual cycle of lightning is varying geographically, e.g. offshore and coastal regions show a lower amplitude of the annual cycle and a later maximum (autumn) compared to inland (mountainous) regions. In addition, the annual and diurnal cycles of lightning attributes are analysed. The analysis reveals rising height of inner-cloud lightning during the year with a maximum in late summer. 相似文献
6.
The lightning activity and precipitation in two 3-hour time intervals in the grid boxes of 0.25 × 0.25° over East and Central Mediterranean during the summer of 2005 and 2006 are analysed. The results show that the frequency distribution of the precipitation amount is shifted towards larger values for the cases with lightning as compared with the cases without lightning. It was found that the number of cases with 3-hour accumulated rainfall greater than 10 mm was bigger when lightning occurred (65%) than when it was absent (35%). Investigation of diurnal and spatial distributions of lightning shows that the afternoon flash density peak is associated mainly with lightning over the land, which is in accordance with the results of earlier works. The early morning flash density peak is associated mainly with flashes over the sea. High correlation coefficients (0.89 during the morning hours and 0.98 during afternoon) were found between rain rate (mm/h) and average flash density (fl/km2) when flash density is averaged in logarithmic intervals of rain rate. 相似文献
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北京市自然雷电与雷电灾害的时空分布 总被引：9，自引：1，他引：8
利用1995-2002的LIS/OTD卫星雷电资料(以下称自然雷电)及1995-2005年北京市18个区县的雷电灾害资料,对北京市自然雷电和雷电灾害的时空分布特征进行对比分析.结果表明,北京市雷电灾害的日变化与自然雷电的日变化趋势大体一致,两者不一致处主要与人们的出行生活规律以及电子设备与仪表的启用、关闭等有关.雷电灾害与自然雷电的季节变化大体一致,春、秋、冬三季较少,夏季较为集中.北京市自然雷电与雷电灾害的区域分布很不一致.自然雷电较多的北部偏远郊区雷电灾害并不频繁,相反,自然雷电较少的城区反而是雷电灾害的多发区域.结合北京市各区县的人口和经济资料进一步分析表明:自然雷电只是北京市雷电灾害的致灾因子之一,北京市雷电灾害的发生还受到人口密度及经济特征等因素的制约. 相似文献
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利用雷州半岛2007年7、8月常规地面气象观测资料和闪电定位资料,分析了闪电活动与24 h降水量及雨强的关系,结果表明:雷州半岛盛夏地闪频数的最大值中心在其东侧海面上,地闪高发带沿海岸线呈南北向分布;地闪频次存在明显的日变化特征,13:00～18:00为闪电高发时段;无闪电时,有41.3%的降水事件24 h降水量≤1 mm,61.5%的降水事件雨强≤1 mm·h-1;有闪电时相应的事件概率分别为25.9%和37.7%;24 h降水量>30 mm的事件大多发生在有闪电的情况下,无闪电时极少发生;雨强概率分布的日变化特征不明显;有闪电活动时,雨强均值变化幅度加大. 相似文献
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基于国家雷电定位网2010—2014年雷电定位数据和2010—2013年地面气象资料,分析了北京地区各季地闪活动时空分布特征及其与降水量的关系。结果表明,北京地区雷电活动具有明显的日变化特征;雷电发生频次随季节变化明显,负闪和全地闪在秋季变化幅度最大;雷电发生频次最大值和最小值出现时间随季节变化,春季、夏季日循环峰值出现时间在22∶00—23∶00(北京时间),秋季日循环峰值出现时间在01∶00,冬季则为15∶00且不具有显著性;从空间分布上看,可以看出雷电活动分布具有局地性特征,北京地区雷电活动最频繁的地区集中在密云县和平谷区的迎风坡一带、通州区与市辖区交界处,高雷暴日区域位于延庆县、昌平区和平谷西部,延庆县和怀柔区的北部及房山区和门头沟交界处的西部,雷暴发生频次和雷暴日空间分布不完全吻合。通过各季雷电发生频次日变化序列的谐波分析可知,日循环为日变化的主要信号。春季、夏季、秋季雷电发生频次和降水量两者整体变化趋势一致,降水量较雷电发生频次变化缓慢。 相似文献
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利用湖北省2013—2018年6—8月ADTD闪电探测数据对该地区的闪电活动进行特征分析后发现, 地闪密度和日变化特征与地形密切相关, 其中, 闪电密度高值区出现在海拔500~1 500 m的中尺度山脉向平原的过渡地带以及山脉之间的平原(河谷)地区; 山区的地闪集中在午后至傍晚时段, 具有明显的单峰特征, 平原的地闪日变化相对平缓, 虽然主峰值同样出现在午后, 但夜间地闪活动依然活跃。基于2015—2016年6—8月逐6 min雷达组合反射率拼图产品和地闪资料挑选了94例伴有显著闪电活动的雷暴系统个例, 经统计分析后发现, 雷暴系统的初次地闪、峰值地闪和末次地闪均集中出现在13:00—18:00, 其中, 山区雷暴的地闪持续时间较短, 地闪频数峰值较小; 平原雷暴的地闪持续时间更长, 地闪频数峰值也更大; 山麓雷暴的特征则介于两者之间。利用ERA-Interim再分析资料进行成因分析后可知, 地形强迫和局地热力不稳定是影响湖北山区夏季闪电密度分布和日变化特征的关键因子。 相似文献
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选取了青藏高原东北侧临夏站1980—2010年的雷暴观测资料和陇中地区闪电定位仪2006—2010年的闪电观测资料,利用统计学手段对该地区雷电的年际变化、年变化、日变化、首次发生雷暴方向、地闪密度等进行了分析.基本揭示了该地区雷电的发生特征,发现一年中雷电主要发生在夏季,一天中雷电主要发生在下午及傍晚,地闪密度高于中国平均密度.对该地区雷电灾害防灾减灾工作有一定的促进意义. 相似文献
12.
Marine-Atmospheric Boundary Layer Characteristics over the South China Sea During the Passage of Strong Typhoon Hagupit 
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下载免费PDF全文 CHENG Xueling WU Lin SONG Lili WANG Binglan ZENG Qingcun 《Acta Meteorologica Sinica》2014,28(3):420-429
The structures and characteristics of the marine-atmospheric boundary layer over the South China Sea during the passage of strong Typhoon Hagupit are analyzed in detail in this paper. The typhoon was generated in the western Pacific Ocean, and it passed across the South China Sea, finally landfalling in the west of Guangdong Province. The shortest distance between the typhoon center and the observation station on Zhizi Island(10 m in height) is 8.5 km. The observation data capture the whole of processes that occurred in the regions of the typhoon eye, two squall regions of the eye wall, and weak wind regions,before and after the typhoon's passage. The results show that:(a) during the strong wind(average velocityˉu 10 m s-1) period, in the atmospheric boundary layer below 110 m, ˉu is almost independent of height,and vertical velocity ˉw is greater than 0, increasing with ˉu and reaching 2–4 m s-1in the squall regions;(b) the turbulent fluctuations(frequency 1/60 Hz) and gusty disturbances(frequency between 1/600 and1/60 Hz) are both strong and anisotropic, but the anisotropy of the turbulent fluctuations is less strong;(c) ˉu can be used as the basic parameter to parameterize all the characteristics of fluctuations; and(d) the vertical flux of horizontal momentum contributed by the average flow(ˉu ·ˉw) is one order of magnitude larger than those contributed by fluctuation fluxes(u w and v w), implying that strong wind may have seriously disturbed the sea surface through drag force and downward transport of eddy momentum and generated large breaking waves, leading to formation of a strongly coupled marine-atmospheric boundary layer. This results in ˉw 0 in the atmosphere, and some portion of the momentum in the sea may be fed back again to the atmosphere due to ˉu ·ˉw 0. 相似文献
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车载应急气象台防雷设计 总被引：1，自引：0，他引：1
车载应急服务移动气象台主要用于突发性事件、重大气象灾害、重大社会活动等应急气象保障工作,使抢险救灾和重大社会活动现场气象服务更直接、更及时、更有效。体现了气象工作在不同环境和恶劣自然条件下开展气象观测、探测、天气预报预测,提供准确的气象预报服务能力。 相似文献
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Hourly lightning data were obtained from the Tropical Rainfall Measuring Mission dataset collected through the Lightning Imaging Sensor instrument from 1998 to 2011 to analyze the diurnal pattern of lightning activity in the tropical and subtropical northern hemispheric Americas. The majority of the lightning strikes occurred over land, with relatively lower strike rates over the oceanic areas. The results of our studies showed substantial spatial variations in the time of maximum and strength of the diurnal cycle in the study area. A clockwise progression in the time of maximum was observed across most of the study area, particularly over North America where an east–west orientation was observed. The findings of our study were mainly a result of the interaction between local topography such as the Andes and Rocky mountains, and surface level atmospheric circulations. The strength of the observed diurnal cycle was greatest in the Gulf of Mexico region. 相似文献
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Climatological patterns in wind fluctuations on time scales of 1-10 h are analyzed at a meteorological mast at the Yangmeishan wind farm, Yunnan Province, China, using a 2-yr time series of 10-min wind speed ob- servations. For analyzing the spectral properties of non- stationary wind fluctuations in mountain terrain, the Hil- bert-Huang transform （HHT） is applied to investigate climatological patterns between wind variability and sev- eral variables including time of year, time of day, wind direction, and pressure tendency. Compared with that for offshore sites, the wind variability at Yangmeishan wind farm has a more distinct diurnal cycle, but the seasonal discrepancies and the differences according to directions are not distinct, and the synoptic influences on wind vari- ability are weaker. There is enhanced variability in spring and winter compared with summer and autumn. For flow from the main direction sector, the maximum wind vari- ability is observed in spring. And the severe wind fluctua- tions are more common when the pressure tendency is rising. 相似文献
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Seasonal Prediction of the Global Precipitation Annual Modes with the Grid-Point Atmospheric Model of IAP LASG 下载免费PDF全文
下载免费PDF全文 A right annual cycle is of critical importance for a model to improve its seasonal prediction skill. This work assesses the performance of the Grid-point Atmospheric Model of IAP LASG （GAMIL） in retrospective prediction of the global precipitation annual modes for the 1980 2004 period. The annual modes are gauged by a three-parameter metrics： the long-term annual mean and two major modes of annual cycle （AC）, namely, a solstitial mode and an equinoctial asymmetric mode. The results demonstrate that the GAMIL one-month lead prediction is basically able to capture the major patterns of the long-term annual mean as well as the first AC mode （the solstitial monsoon mode）. The GAMIL has deficiencies in reproducing the second AC mode （the equinoctial asymmetric mode）. The magnitude of the GAMIL prediction tends to be greater than the observed precipitation, especially in the sea areas including the Arabian Sea, the Bay of Bengal （BOB）, and the western North Pacific （WNP）. These biases may be due to underestimation of the convective activity predicted in the tropics, especially over the western Pacific warm pool （WPWP） and its neighboring areas. It is suggested that a more accurate parameterization of convection in the tropics, especially in the Maritime Continent, the WPWP and its neighboring areas, may be critical for reproducing the more realistic annual modes, since the enhancement of convective activity over the WPWP and its vicinity can induce suppressed convection over the WNP, the BOB, and the South Indian Ocean where the GAMIL produces falsely vigorous convections. More efforts are needed to improve the simulation not only in monsoon seasons but also in transitional seasons when the second AC mode takes place. Selection of the one-tier or coupled atmosphere-ocean system may also reduce the systematic error of the GAMIL prediction. These results offer some references for improvement of the GAMIL seasonal prediction skill. 相似文献
17.
In May 2008, ScienceWatch.com named Advances in Atmospheric Sciences a Rising Star among Geosciences journals. According to Essential Science IndicatorsSM from Thomson Reuters, the journal＇s cur-rent citation record includes 764 papers cited a total of 1,658 times between January 1, 1998 and February 29 2008. 相似文献
18.
Tides and Wind-Driven Circulation in the Tropical and Southern Atlantic Ocean:The BRAZCOAST System 下载免费PDF全文
下载免费PDF全文 The Brazilian coast is characterized by dif- ferent tidal regimes and distinct meteorological influ- ences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical distur- bances; the southern portion has smaller tidal amplitudes and is frequently influenced by extratropical cyclone ac- tivity. Besides these aspects, many features regarding current structure and behavior are also present, such as the equatorial system of currents, the subtropical gyre and the corresponding western boundary currents, and the Bra- zil-Malvinas confluence region. Within this context, ef- forts were made to develop the BRAZCOAST system, capable of describing the processes that determine the oceanic circulation from large to coastal scales. A cus- tomized version of the Princeton Ocean Model （POM） was implemented in a basin-scale domain covering the whole of the tropical and southern Atlantic Ocean, with 0.5° spatial resolution, as well as three nested grids with （1/12）° resolution covering the different parts of the Bra- zilian shelf, in a one-way procedure. POM was modified to include tidal potential generator terms and a par- tially-clamped boundary condition for tidal elevations. The coarse grid captured large-scale features, while the nested grids detailed local circulations affected by bathymetry and coastal restrictions. An interesting aspect at the coarse grid level was the relevance of the Weddell Sea to the location of the tidal amphidromic systems. 相似文献
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Case Study on the Impact of the Vortex in the Easterlies in the Tropical Upper Troposphere on the Western Pacific Subtropical Anticyclone 总被引：2，自引：0，他引：2 下载免费PDF全文
下载免费PDF全文 By employing the NCEP/NCAR reanalysis data （1000-10 hPa, 2.5°×2.5°）, the impact of the vortex in the easterlies （EV） over the tropical upper troposphere on the zonal movement of the western Pacific subtropical anticyclone （WPSA） during 19-25 June 2003 is analyzed in this paper. It is shown that the EV can extend from middle troposphere to the height of 50 hPa, reaching a maximum at 200 hPa. The vertical thermal distribution appears to be ＂warmer in the upper layer and colder in the lower layer＂. The WPSA retreats eastward abnormally when the EV and the vortex in the westerlies （WV） encounter around the same longitude while they move toward each other. It is also shown that the vorticity variation extends from the troposphere to the height of 50 hPa, with the most prominent change occurring at 200 hPa by the diagnostic analyses of the vertical vorticity equation. The WPSA appears to retreat abnormally eastward while the negative/positive vorticity change becomes stronger near the east/west side of the EV, and the areas with positive vorticity tendency both in the EV and WV join together into one belt along 130°E during the process of the EV and the WV moving toward each other. In the vorticity equation, the positive contribution caused by the horizontal advection term is the maximum, and the minimum is caused by theβ effect. It is also found that enhanced horizontal vorticity advection andβ effect, as well as the ＂barotropic development＂ resulted from the in-phase superposition of the southerly and the northerly winds in the easterlies and westerlies near 130~E, are in agreement with the WPSA eastward retreat. 相似文献
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利用DEM高程数据和2008—2020年重庆地区ADTD闪电定位资料,研究了重庆地区复杂地形影响下的地闪活动特征。结果表明:（1）重庆地区地闪活动空间分布具有明显的区域性差异,且与地形及海拔高度密切相关,整体表现为自西向东,由盆地、丘陵到高山山地区域地闪活动逐渐减弱,正地闪占比逐渐增大的特征;（2）重庆地区地闪活动年际变化分布不均,月变化呈单峰型,7月为峰值,主要集中在4—9月,占全年的96.3%,日变化呈双峰型,夜间峰值集中在00:00—04:00,白天峰值集中在14:00—18:00,08:00—12:00为地闪活动最弱时段;（3）地闪活动月、季节尺度变化主要受大尺度天气系统支配,地形及海拔高度对地闪活动影响主要体现在日变化的显著差异上,在海拔1 000 m以下的盆地、丘陵和低山区域,夜间地闪频数明显多于白天,具有夜间主导型特征,海拔1 000 m以上的高山山地区域,白天地闪频数多于夜间,具有白天主导型特征,海拔高度越高,闪电越易出现在白天;（4）正地闪强度明显大于负地闪,地形及海拔高度变化对地闪强度影响不明显。 相似文献