排序方式： 共有48条查询结果，搜索用时 15 毫秒
41.
通过分析1995~2011年间中国学者在中国学术期刊网络出版总库（简称CAJD）收录期刊上发表的气象服务效益评估的论文,了解我国气象服务效益评估领域科研状况。通过对气象服务效益评估论文数量、期刊来源、作者分布、关键词及基金等分布情况进行文献统计分析。结果表明,在CAJD数据库收录气象服务效益评估的论文达110篇,作者合著率74.5%,合作度2.6,关键词中词频最高的是＂经济效益＂,涉及各类基金项目资助40项。同时发现,尽管中国气象服务效益评估研究发展迅速,但核心作者群有待加强,研究内容集中在评估实践方面,缺少在评估理论和技术上有所创新的论文。 相似文献
42.
The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project 总被引：4，自引：1，他引：3
Robert Vautard Andreas Gobiet Daniela Jacob Michal Belda Augustin Colette Michel Déqué Jesús Fernández Markel García-Díez Klaus Goergen Ivan Güttler Tomáš Halenka Theodore Karacostas Eleni Katragkou Klaus Keuler Sven Kotlarski Stephanie Mayer Erik van Meijgaard Grigory Nikulin Mirta Patarčić John Scinocca Stefan Sobolowski Martin Suklitsch Claas Teichmann Kirsten Warrach-Sagi Volker Wulfmeyer Pascal Yiou 《Climate Dynamics》2013,41(9-10):2555-2575
The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly. 相似文献
43.
基于NCEP再分析资料和常规气象观测资料,采用数值模拟方法,从大尺度环流、中尺度系统和对流能量三方面,对2016年5月7—8日江西省抚州地区的一次连续性对流天气过程的两个阶段暴雨进行了对比分析。结果表明,对流层高层辐散气流、中层短波槽前正涡度平流、低层切变线和低空急流的良好配置以及系统长时间的稳定维持,是造成此次连续性对流过程的主要原因。阶段一,对流在切变线附近产生,对流产生后形成的中尺度锋区又使得新对流在锋区附近激发,形成列车效应,造成了暴雨的发生;阶段二,对流位于暖区,由降水区上游移来的对流系统在低层暖中心附近得到发展加强,暖中心的长时间维持造成了暴雨的发生。阶段一的能量主要来源于前期大气积累的不稳定能量;阶段二的能量则是在西南气流输送下数小时内快速累积。 相似文献
44.
基于高分辨率高程数据统计分析新一代天气雷达组网的地形遮挡影响 总被引：1，自引：0，他引：1
新一代天气雷达由于受到地形限制产生波束遮挡导致波束能量衰减,从而造成雷达探测回波强度偏弱、雷达定量估测降水结果失真,因此对于雷达波束遮挡情况的统计和分析是一项重要的基础研究工作。利用SRTM （Shuttle Radar Topography Mission）数字高程数据对中国目前业务运行的212部新一代天气雷达波束遮挡情况进行模拟计算分析。计算结果包括雷达单站遮蔽角、VCP21模式0.5°、1.5°、2.4°、3.4°、4.3°仰角波束遮挡率、混合扫描及分区混合扫描波束遮挡率、雷达单站探测范围覆盖情况;计算并绘制全国天气雷达组网遮挡率拼图,统计全国天气雷达组网遮挡情况;利用2019年8月广东省11部天气雷达基数据对比验证单站及组网遮挡计算结果。结果表明雷达组网探测面积覆盖率超过70%,整体覆盖效果较好,遮挡计算结果与实际数据对比验证结果高度一致,对雷达数据订正、降水估测等产品具有正贡献。 相似文献
45.
利用常规探空和地面观测资料、卫星雷达资料以及NCEP再分析数据,应用非地转湿Q矢量和湿位涡理论,诊断分析了2018年第4号台风"艾云尼"登陆后的倒槽暴雨过程。结果表明,台风倒槽东侧偏南气流为暴雨区温湿能量的主要来源,倒槽顶部的暖式切变和倒槽西侧高值湿位涡的下传,使大气斜压性和低层不稳定度增强。倒槽附近温度场与风场的不平衡配置易于激发次级环流,有利于潜热能的释放和暴雨的增幅。暴雨区对流层低层(925 hPa)湿位涡分量总满足MPV10,MPV20。中层非地转湿Q矢量散度与未来6 h降水落区对应较好,对此类台风倒槽类暴雨预报具有一定的指示意义。 相似文献
46.
基于2014—2016年京津冀地区学龄前儿童流感发病人数和气象观测数据,研究了学龄前儿童流感发病与单个气象要素以及综合气象条件的关系,结果表明:该地区学龄前儿童流感发病人数与一周以内的气温、相对湿度、气压和综合气象条件指标—大气环境人体感知度（BPWI）存在显著线性相关。大气环境人体感知度与学龄前儿童流感具有更稳定的暴露-反应关系:当BPWI≤?11或0≤BPWI<10 时,随着BPWI减小,流感发病风险增大。气压是另一个显著影响流感发病的气象要素:当本站气压>905 hPa,随着气压的升高,流感发病人数增多;当本站气压达到1007 hPa时,流感发病风险达到峰值。在厘清暴露-反应关系的基础上,采用机器学习方法进行预报建模,发现超前3天的BPWI对流感发病人数贡献最大。通过历史回报检验,得到了较好的学龄前儿童流感发病回报效果,为流感的分类人群干预提供了预报依据和科学参考。 相似文献
47.
本文以新疆麦盖提灰枣为例,在基于气象观测资料开展气候品质评价的基础上,将FY-4A卫星遥感数据、高分辨率多源融合实况格点产品(ART-1km、CLDAS-V2.0、Laps)应用于农产品气候品质评价,研制了点面结合的网格化农产品气候品质评价模型,阐述了基于多源数据融合的农产品气候品质评价方法。结果表明,通过该方法可明显提高农产品气候品质评价结论的可靠性和精细化程度,同时也可解决无观测资料地区农产品气候品质评价问题。 相似文献
48.
基于1961-2018年1 057个地面气象站均一化气温日值数据和通过均一化检验的日降水量资料,统计得到冬春季低温连阴雨过程,分析其时空分布及变化特征。结果表明,湖南、贵州、江西三省为低温连阴雨集中发生地区,连续最长低温连阴雨超过15 d的台站集中在25°~31°N之间的区域。由经验正交函数方法分析表明,南方地区低温连阴雨日数总体上表现为一致偏多或偏少的分布型,且具有东北部与西南部反相变化、东部与西部反相变化的分布型。南方冬春季平均低温连阴雨日数总体呈减少趋势,约为-0.17 d/(10 a)。1960s末期至1990s低温连阴雨日数以偏多为主,从2000年开始以偏少为主。 相似文献