Seasonal Prediction of Spring Dust Weather Frequency in Beijing          下载免费PDF全文

LANG Xianmei 《Acta Meteorologica Sinica》2011,25(5):682-690

In this paper, seasonal prediction of spring dust weather frequency (DWF) in Beijing during 1982-2008 has been performed. First, correlation analyses are conducted to identify antecedent climate signals during last winter that are statistically significantly related to spring DWF in Beijing. Then, a seasonal prediction model of spring DWF in Beijing is established through multivariate linear regression analysis, in which the systematic error between the result of original prediction model and the observation, averaged over the last 10 years, is corrected. In addition, it is found that climate signals occurring synchronously with spring dust weather, particularly meridional wind at 850 hPa over western Mongolian Plateau, are also linked closely to spring DWF in Beijing. As such, statistical and dynamic prediction approaches should be combined to include these synchronous predictors into the prediction model in the real-time operational prediction, so as to further improve the prediction accuracy of spring DWF in Beijing, even over North China. However, realizing such a prediction idea in practice depends essentially on the ability of climate models in predicting key climate signals associated with spring DWF in Beijing.  相似文献   

Regional Temperature Forecast for the Next Day in Hong Kong          下载免费PDF全文

LAM Hil  SHUM Karen Kit-ying  TANG Julian Shu-yan 《Acta Meteorologica Sinica》2011,25(6):725-733

For a century or so, the Hong Kong Observatory (HKO) has been providing temperature forecast for the whole of Hong Kong with the HKO Headquarters as the reference location. In recent decades, due to spreading of population from the main urban center to satellite towns, there is an increasing demand for regional temperature forecasts. To support such provision, the HKO has developed a regression model to provide objective guidance to forecasters in formulating forecasts of maximum and minimum temperatures for the next day at various locations in Hong Kong. In this paper, the regression model is presented, together with the assessment of its performance. Based on the verification of one year of forecasts, it is found that the root mean square errors (RMSEs) of maximum (minimum) temperature forecasts are from about 1.3 to 2.1 (1.1 to 1.4) degrees, respectively. The regression model is shown to have generally out-performed the operational regional spectral model then operated by HKO. Regional temperature forecast methods of other meteorological or research centers are also surveyed. Equipped with the regression model, the HKO has launched an online regional temperature forecast service for the next day in Hong Kong since March 2008.  相似文献   

Assessing the effectiveness of non-structural flood management measures in the Thames Estuary under conditions of socio-economic and environmental change   总被引：1，自引：0，他引：1  

Richard J. Dawson  Tom Ball 《Global Environmental Change》2011,21(2):628-646

Risk analysis and appraisal of the benefits of structural flood risk management measures such as embankments is well established. Here, a method to quantify, over extended timescales, the effectiveness of non-structural measures such as land use spatial planning, insurance and flood resilient construction is presented. The integrated approach couples socio-economic and climate change scenarios with long term land use modelling and flood risk analysis to generate maps and time series of expected annual damages. The analysis has been applied on a case study in the Thames Estuary in the UK. Stakeholders helped develop a number of scenarios that might lead to substantial changes in existing planning and insurance policies in the UK. The effectiveness of these changes was analysed and showed the substantial benefits in terms of reduction of future flood risks that are achievable with changes in planning policy, financial incentives and resilient property construction in the floodplain. Moreover, the reward can be increased through earlier action. Subsequently, the benefits of a range of policies are explored under the UK Foresight socio-economic scenarios. Different structural and non structural flood management interventions are tested and the results demonstrate that despite the potential for large increases in flood risk in the Thames Estuary, in all scenarios substantial flood risk reductions are possible. The effectiveness of non-structural measures is however sensitive to socio-economic changes and governance arrangements. The analysis described here will help to identify portfolios of non-structural and structural options that are robust to uncertainties.  相似文献   

Testing resilience thinking in a poverty context: Experience from the Niger River basin     

Christophe Béné  Louisa Evans  David Mills  Solomon Ovie  Aminu Raji  Ahmadu Tafida  Amaga Kodio  Famory Sinaba  Pierre Morand  Jacques Lemoalle  Neil Andrew 《Global Environmental Change》2011,21(4):1173-1184

Resilience thinking is an important addition to the range of frameworks and approaches that can be used to understand and manage complex social–ecological systems like small-scale fisheries. However, it is yet to lead to better environmental or development outcomes for fisheries stakeholders in terms of food security, improved livelihoods and ecological sustainability. This paper takes an empirical approach by focusing on the fundamentals of resilience thinking to evaluate its usefulness in developing relevant management interventions in small-scale fisheries in the Niger River Basin in West Africa. The paper presents the outputs of a participatory assessment exercise where both fishery communities and local experts were involved at two different scales. The resilience frame used was designed to facilitate the identification of socially defined thresholds that help delineate the desirability of the current system configuration and provides a diagnosis framework that tailors management solutions to problems in local context. The analysis highlights some key contributions from resilience thinking to the challenge of diagnosis in small-scale fisheries management in developing countries, as well as important contributions that emerge from taking a pragmatic and critical approach to its application.  相似文献   

边界层风廓线仪多普勒频谱高度图综合应用初探   总被引：2，自引：2，他引：0  

吴志根  丁若洋  郑杰  陈浩君  查亚峰  李建成  胡平 《气象》2011,37(8):1006-1017

文章介绍了边界层风廓线仪多普勒频谱高度图的原理,并且给出了无降水、有降水、降雪、速度折叠、地物杂波、外界信号干扰等典型的多普勒频谱高度图型。研究发现,多普勒频谱高度图除了可以从中提取测风产品所需的数据外,该在线显示的图形还实时提供了许多其他潜在的气象信息,并可用于：连续监视测站上空天气;提前了解测站上空风的垂直切变;发现并确定降水起始时间;在线估测风向风速;实时判别降水云底高度和0°层的范围;验证和解释风羽剖面图产品中的奇异现象;帮助固定和移动风廓线仪选址;诊断风廓线仪系统故障;评价风廓线仪系统软/硬件性能优劣等。文章指出：深入发掘边界层风廓线仪在降水天气系统中进行高时间密度探测的潜力,使得它可以晴雨两用,对今后将边界层风廓线仪配备到一般气象观测站,提高单站天气监测/预警能力和开展精细化天气预报意义深远。文章还对当前商业化的边界层风廓线仪提出了具体的改进意见,以满足频谱在线分析的需要。  相似文献   

北京快速更新循环预报系统（BJ-RUC）要素预报质量评估   总被引：4，自引：2，他引：2  

魏东  尤凤春  杨波  范水勇  陈敏 《气象》2011,37(12):1489-1497

使用自动站观测资料对BJ-RUC系统预报的北京15个观测站的逐时2 m温度、相对湿度、1小时降水量和风速等地面要素质量进行检验评估。结果表明：BJ-RUC系统预报的2 m温度、相对湿度和风速与实况具有一致的变化趋势,但各要素的预报性能不尽相同。结果表明：（1）对于2 m温度的预报,±1℃误差的准确率为0.2～0.5,±2℃误差的准确率更高;预报性能与预报时效无明显关系;温度预报准确性与季节和日变化有关,春、秋季优于冬、夏季,夜间优于白天。（2）对相对湿度的预报整体偏低,夏季白天偏低、冬季白天偏高。（3）对1小时降水的预报,无论全年还是夏季,晴雨预报准确率很高;对0.1 mm降水的TS评分在0.2左右。（4）对不同站点的预报性能存在明显差异。对平原地区,即海拔高度较低的站点预报性能相对较好,15个站点中,对北京的代表站点（南郊观象台）的预报最为准确;对山区站点的预报性能相对较差,对海拔最高的延庆站的预报性能最差。总体来说,BJ RUC对站点要素预报的变化趋势较好,预报准确率较高,具有很好的参考价值,但要素预报与季节、日变化及海拔高度等因素有关.具体应用时还需做适当订正。  相似文献   

梅雨准双周振荡的年际变化及其前期强信号分析   总被引：2，自引：2，他引：0  

尹志聪  王亚非  袁东敏 《南京气象学院学报》2011,34(3):297-304

利用1954—2005年中国740站逐日降水资料和NCEP/NCAR再分析资料,分析了江淮梅雨准双周振荡的年际变化,并讨论了异常年的海气背景特征。将滤波后的每个降水周期划分为8个位相,其中第3位相对应准双周降水正距平最大,而第7位相对应准双周降水负距平最大,在此基础上的诊断结果表明：1）振荡强弱偏差场,在梅雨降水偏多的第3位相,低层大气中类似Rossby波列从南海经日本海、鄂霍次克海和阿留申群岛延伸至阿拉斯加地区,其中南海上空的反气旋和日本上空的气旋相互配合,造成冷暖空气在江淮地区交汇,有利于准双周降水正距平的产生。在降水偏少的第7位相,波列位相基本反向,传播路径偏南。2）第3位相时高层环流显示,鄂霍次克海地区高度场正异常明显,和我国东北地区的负距平共同作用为梅雨降水提供了足够的干冷空气。第7位相分布相反。3）前期3月至同期的黑潮及其延伸区海表温度和梅雨的准双周振荡强强度之间呈很好的正相关关系。黑潮及其延伸区持续的正海温异常,通过影响西太平洋副热带高压的位置和强度的变化,进而增强梅雨降水的准双周振荡  相似文献   

基于ArcGIS Server和VML的气象信息发布平台   总被引：1，自引：1，他引：0       下载免费PDF全文

张永华  肖文名  何婉文  孙周军 《应用气象学报》2011,22(4)

该文采用ESRI公司的ArcGIS Server配合ArcSDE,Oracle数据库软件,结合ASP.NET,JavaSeript,VML,Ajax技术开发了基于ArcGIS Server和VML技术的气象信息发布系统.该系统将实时气象资料融入实际的地理信息环境,实现动态信息查询、统计及各种统计图表展示,并充分发挥GIS空间分析能力,实现等值面、面雨量、缓冲区和叠加分析,为气象预报工作提供及时、有效、科学的辅助决策支持,为社会提供优质气象服务.  相似文献   

WRF模式三维变分中背景误差协方差估计   总被引：2，自引：1，他引：1       下载免费PDF全文

王曼  李华宏  段旭  刘建宇  符睿  陈新梅 《应用气象学报》2011,22(4):482-492

利用WRF模式2008年5-10月逐日预报结果,通过NMC方法进行背景误差协方差(B)估计.给出其结构特征,进行单点数值试验,并利用不同B进行1个月的数值模拟试验,检验模拟降水效果.结果表明:通过单点数值试验验证估算的B结构合理.不同的B,资料同化过程差别较大,应用重新统计的B,同化效率更高,目标函数收敛更稳定.模式模...  相似文献   

华北一次强对流暴雨的湿位涡诊断分析     

高万泉  周伟灿  李玉娥 《辽宁气象》2011,(1):1-6

应用常规地面观测资料、区域加密站降水资料、NCEP再分析资料（水平分辨率为1°×1°,时间间隔为6 h）,对2009年6月8日发生在华北的一次强对流暴雨过程的湿位涡场进行了诊断分析。结果表明：湿位涡的分布对强对流暴雨的发生、落区有较强的指示性作用,MPV1＂正负值区垂直叠加＂的配置是强对流暴雨发生、发展的有利形势。暴雨出现在850 hPa上MPV、MPV1、MPV2正负值过渡带附近,是对流不稳定与斜压不稳定相结合的地区。θse等值线接近垂直的地区有利于垂直涡度的增长,亦有利于强降水发生。  相似文献