Storm-related sea level variations along the North Sea coast as simulated by a high-resolution model 1958–2002     

Ralf Weisse  Andreas Plüβ 《Ocean Dynamics》2006,56(1):16-25

Storm-related sea level variations 1958–2002 along the North Sea coast from a high-resolution numerical hindcast are investigated and compared to the results of earlier studies. Considerable variations were found from year to year and over the entire period. The large-scale pattern of these variations is consistent with that derived from previous studies, while the magnitudes of the long-term trends differ. The latter is attributed to different analysis periods, improvements in the atmospheric forcing, and the enhanced spatial resolution of the numerical simulation. It is shown that the different analysis periods, in particular, represent an issue as the increase in storm-related sea levels was found to be weaker over the last few years that have not been included in earlier studies. These changes are consistent with observed changes of the storm climate over the North Sea. It is also shown that observed and hindcast trends may differ significantly. While the latter are in agreement with observed changes in the storm climate, it may be concluded that observed sea level changes along the North Sea coast comprise a considerable fraction that cannot be attributed to changes in the large-scale atmospheric circulation.

Ralf WeisseEmail:

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大气Rossby波动力学的研究进展   总被引：5，自引：0，他引：5  

谭本馗 《气象学报》2008,66(6):870-879

Rossby波是旋转大气和海洋中的一类重要波动,在天气和气候演变中起有重要的作用。该文介绍了北半球中纬度地区的两类重要Rossby波——斜压不稳定波和准定常行星波,在最近20余年来取得的一些重要研究进展。文中涉及的主要研究领域有:斜压不稳定波包动力学、湿斜压过程对斜压不稳定波的作用、北半球风暴轴动力学、斜压波包与高影响天气的预报、准定常行星波的形成机理、准定常行星波的水平传播与能量频散、准定常行星波的垂直传播与能量频散、三维准定常行星波的传播与能量频散。  相似文献   

都安一次特大暴雨过程卫星和雷达图像特征分析   总被引：1，自引：1，他引：0  

唐新  林宗桂  黎家宜  林墨  罗红磊 《气象研究与应用》2010,31(3)

利用彩色增强显示的卫星云图、雷达和自动气象站资料对2010年5月31日22时至6月1日11时都安县出现的特大暴雨进行分析,发现这次暴雨过程由2个强降雨阶段组成,造成都安县特大暴雨的原因是1个形成于滇黔桂交界处的低涡在南移过程中,低涡东边缘对流强烈发展,对流云团主体移过都安而产生了强降雨,对应着这2个强降雨阶段,在卫星云图上分析出是由2个对流云团前后移过所造成的,在雷达回波图上可分析出对流云团中又先后有多个对流单体移过都安县上空,所以造成了这次特大暴雨过程  相似文献   

2008年7月14—15日川西暴雨过程的温度层结变化分析     

肖递祥  顾清源  祁生秀 《湖北气象》2009,28(1)

2008年7月14-15日,四川盆地西部"5.12"汶川大地震重灾区在非典型热力条件下出现了一次暴雨天气过程.本文利用常规观测资料和NCEP 1°×1°再分析资料,对其天气形势及温度层结变化特征进行了详细分析.结果表明:(1)暴雨发生在副热带高压不断西伸的环流背景下,低层偏南气流及其风速脉动对暴雨产生具有重要作用.(2)暴雨开始于850hPa θse下降及大气层结为弱稳定的非典型热力条件下,但700 hPa θse突增使得700-500 hPa对流性不稳定层建立,从而利于对流运动发展;暴雨过程后期,因850 hPa和700 hPa θse急剧下降和大气层结稳定度增大,对流上升受到明显抑制.(3)低层θse锋区和水汽辐合对强降水具有指示意义,暴雨落区位于850 hPa和700 hPa θse锋区前沿,降水中心位于水汽汇合中心附近.  相似文献   

一次华南暴雨过程中不同区域降水特征的模拟分析   总被引：6，自引：5，他引：1  

史荟燕  潘晓滨  谢海军  臧增亮  何亿强 《气象科学》2009,29(1):58-63

通过对2005年6月19-20日的一次华南大暴雨过程的诊断分析表明,本次降水过程的水汽来源有两个,一是来自于印度洋上的印度季风,另一个是来自于澳大利亚的东南信风.对不同暴雨中心的分析表明,福建北部的降水带为华南准静止锋锋面上的系统性降水,假相当位温的经向垂直剖面呈明显的Ω型结构,而广东河源附近的暴雨中心为暖区对流性降水,低层为强的不稳定.利用ARPS模式对这次暴雨过程进行了数值模拟,结果表明,锋面雨带主要来自于网格降水的贡献,而对流性降水主要来自于次网尺度降水的贡献.  相似文献   

Study of the total lightning activity in a hailstorm   总被引：1，自引：0，他引：1  

Joan Montany  Serge Soula  Nicolau Pineda  Oscar van der Velde  Pere Clapers  Glria Sol  Joan Bech  D. Romero 《Atmospheric Research》2009,91(2-4):430-437

A thunderstorm that developed over northeastern Spain on 16 June 2006 is analyzed. This severe thunderstorm produced hailstones as large as 40 mm and had a lifetime of 3 h and 30 min. Radar cross-sections show strong vertical development with cloud echo tops reaching an altitude of 13 km. The specific characteristics of the lightning activity of this storm were: (i) a large amount (81%) of negative cloud-to-ground (−CG) flashes with very low peak currents (< 10 kA in absolute value), (ii) a very large proportion of intra-cloud (IC) flashes with an IC/CG ratio reaching about 400, (iii) a large number of “short” IC flashes (with only 1-VHF source according to SAFIR detection), (iv) a large increase of the −CG flash rate and of the CG proportion near the end of the storm. The rate of −CG flashes with a low peak current were observed to evolve similarly to the rates of IC flashes. Most of them have been assumed to be IC flashes misclassified by the Spanish Lightning Detection Network (SLDN). They have been filtered as it is usually done for misclassified +CG flashes. After this filtering, CG flash rates remained very low (< 1 min^− 1) with +CG flashes sometimes dominant. All the particular lightning activity characteristics similar to those observed in the Severe Thunderstorm Electrification and Precipitation Study (STEPS) campaigns support the hypothesis that this thunderstorm could have had an inverted-polarity or complex charge structure. The maximum IC flash rate (67 min^− 1) peaked 24 min before the presence of reflectivity higher than 60 dBZ. The IC activity abruptly decreased during the period when reflectivity was dramatically increasing. The time of maximum reflectivity observed by radar was consistent with the times of reported hail at the ground.  相似文献   

青草沙水库工程的风险识别     

邓鹏 《中国勘察设计》2010,(9):69-72

青草沙水库工程属大型水利工程。工程在施工阶段和运行期间,均存在不确定性因素多、风险因素和风险事件发生概率大的特点。本文利用风险识别方法,对青草沙水库工程不同阶段的风险进行了识别。  相似文献   

西南低涡暴雨的湿位涡诊断分析   总被引：29，自引：2，他引：29       下载免费PDF全文

李国平  刘行军 《应用气象学报》1994,5(3):354-360

文章分析了１９８１年７月１１－１５日的一次与西南低涡有关的四川特大暴雨过程中的湿位涡变化，发现湿位涡由负变正预示着暴雨的威弱和消失；同时利用湿位涡方程进行了诊断计算，结果表明:暴雨的发展趋势与位涡变率的变化趋势基本一致，位涡变率的正负转换对预报大暴雨的形成和减弱有一定的指示意义。   相似文献   

Suspended sediment in rapid subsurface stormflow on a large field plot     

David H. Pilgrim  Dale D. Huff 《地球表面变化过程与地形》1983,8(5):451-463

The occurrence of rapid movement of suspended sediment in subsurface stormflow on a large field plot in California is described. Concentrations of over 1000mgl^?1 were recorded in storms of only low to moderate intensity. The observed sediment was composed of uniformly fine-sized particles 4 to 8 μm in diameter. The mode of transport seems different from processes previously reported. Differences in sediment concentrations in different events, levels of ¹³⁷Cs on the sediment, and several other types of evidence indicate that the sediment was detached and entrained at the ground surface by raindrop impact and that the water and sediment flow occurred mainly through macropores in the soil. As conditions similar to those at the study site are not uncommon, it seems probable that the phenomenon may occur in many regions.  相似文献   

一次切变线暴雨过程的诊断研究和数值试验   总被引：3，自引：5，他引：3       下载免费PDF全文

郑钢  张铭 《气象科学》2004,24(3):294-302

本文对1998年6月12～13日的一次长江中下游切变线暴雨过程进行了诊断研究并使用一个η坐标细网格暴雨数值模式对其作了数值试验。结果发现，与该暴雨过程相联系的β中尺度系统主要表现在低层的切变线及地面的β中尺度气旋，气旋的东移和发展引起长江中下游大范围强降水，在启动该场暴雨过程中，位势不稳定起了决定性的作用；深厚的β中尺度“涡柱”是该暴雨雨团的明显特征；地形对暴雨的强度和范围均有重要影响，该切变线强度对暴雨过程的降水量也有明显影响。  相似文献