中国黄海西岸海陆风循环结构研究          下载免费PDF全文

Yongxiang Ma  Jinyuan Xin  Xiaoling Zhang  Lindong Dai  Klaus Schaefer  Shigong Wang  Yuesi Wang  Zifa Wang  Fangkun Wu  Xinrui Wu  Guangzhou Fan 《大气和海洋科学快报》2021,14(1):14-21

陆海风是由于海陆表面之间的比热容不同而导致的昼夜热量分布差异,从而在海岸附近引发的大气中尺度循环系统.本文利用多普勒风激光雷达Windcube100s首次对黄海西海岸的海陆风的循环结构进行了观测研究.在2018年8月31日至9月28日观测期间发现,海陆风发展高度一般在700 m至1300 m.海陆风转化持续的时间为6小时至8小时.在425m高度,海风水平风速出现最大值,平均为5.6 m s-1.陆风最大水平风速出现在370m,约为4.5 m s-1.最大风切变指数在1300m处,为2.84;在陆风向海风转换过程中,最大风切变指数在700m处,为1.28.在同一高度上,风切变指数在海风盛行和陆风盛行时的差值范围为0.2-3.6,风切变能反映出海陆风的发展高度.  相似文献   

贵州省2002年秋风特点及成因          下载免费PDF全文

李启芬  汪卫平  胡秋红  蒙军  王兴菊 《中低纬山地气象》2022,46(2):82-87

使用1980到2016年的月平均NCEP再分析资料、贵州省84个国家观测站8月至9月逐日气候态要素值（1981年至2010年的三十年平均）以及贵州省2002年8月至9月气温、降水逐日资料对2002年贵州省出现的特重秋风过程进行分析。结果表明：8月9日至8月23日期间,贵州中西部地区秋风持续时间在9天以上,大部分地区在12天以上,而威宁站长达15天,达特重秋风过程。从春季开始,赤道太平洋地区海表温度自西向东异常偏暖,Nino3.4区持续时间最长,8月份到达最强,导致欧亚大陆中高纬地区经向环流明显且稳定维持,欧洲西海岸、欧亚大陆东北部经贝加尔湖至我国北方地区高度场偏高,欧洲中部明显偏低,我国东北偏低,槽后冷空气较强并南下;孟加拉湾及南海地区的气旋性环流的偏南风与北方南下的冷空气交汇于贵州省,形成静止锋并持续较长时间;8月9日至23日期间的四个台风有利于水汽的输送和环流的维持,使得我省2002年8月低温多雨,秋风灾害严重,尤其造成了8月9日至23日持续时间最长的秋风过程。  相似文献   

Retrieval of Sea Surface Wind Speed by One-Dimensional Synthetic Aperture Microwave Radiometer     

艾未华  冯梦延  陆文  马烁  陈冠宇 《热带气象学报(英文版)》2021,27(1):62-69

One-dimensional synthetic aperture microwave radiometers have higher spatial resolution and record measurements at multiple incidence angles. In this paper, we propose a multiple linear regression method to retrieve sea surface wind speed at an incidence angle between 0° ~65°. We assume that a one-dimensional synthetic aperture microwave radiometer operates at frequencies of 6.9, 10.65, 18.7, 23.8 and 36.5 GHz. Then, the microwave radiative transfer forward model is used to simulate the measured brightness temperatures. The sensitivity of the brightness temperatures at 0°~65° to the sea surface wind speed is calculated. Then, vertical polarization channels(VR), horizontal polarization channels(HR) and all channels(AR) are used to retrieve the sea surface wind speed via a multiple linear regression algorithm at 0° ~65°, and the relationship between the retrieval error and incidence angle is obtained. The results are as follows:(1) The sensitivity of the vertical polarization brightness temperature to the sea surface wind speed is smaller than that of the horizontal polarization.(2) The retrieval error increases with Gaussian noise. The retrieval error of VR first increases and then decreases with increasing incidence angle, the retrieval error of HR gradually decreases with increasing incidence angle, and the retrieval error of AR first decreases and then increases with increasing incidence angle.(3) The retrieval error of AR is the lowest and it is necessary to retrieve the sea surface wind speed at a larger incidence angle for AR.  相似文献   

Performance Evaluation of the GRAPES Model in Wind Simulations Over South China     

钟水新  陈子通  丁伟钰  徐道生  张艳霞  吴凯昕  梁家豪  田群  王立稳 《热带气象学报(英文版)》2021,27(1):1-9

In the present study, the performance of the GRAPES model in wind simulation over south China was assessed. The simulations were evaluated by using surface observations and two sounding stations in south China. The results show that the GRAPES model could provide a reliable simulation of the distribution and diurnal variation of the wind. It showed a generally overestimated southerly wind speed especially over the Pearl River Delta region and the south of Jiangxi Province as well as the coastal region over south China. GRAPES also exhibited a large number of stations with the opposite surface wind directions over the east of Guangxi and the south of Jiangxi during the nocturnal- to-morning period, as well as an overall overestimation of surface wind over the coastal regions during the afternoon. Although GRAPES could simulate the general evolutional characteristics of vertical wind profile, it underestimated wind speed above 900 hPa and overestimated wind speed below 900 hPa. Though the parameterization scheme of gravity wave drag proved to be an effective method to alleviate the systematic deviation of wind simulation, GRAPES still exhibited large errors in wind simulation, especially in the lower and upper troposphere.  相似文献   

Factors influencing hazard management by municipalities: The case of coastal communities     

《Global Environmental Change》2022

As climate and anthropogenic changes increase the vulnerability of coastal areas around the world, the threat (and reality) of coastal hazards grows. These threats arise particularly at a local level, calling out for more knowledge on how to best support coastal municipalities to deal with natural and human-induced hazards. This study seeks to add to the understanding through an examination of local-level experience with hazard planning and responses carried out by coastal municipalities, producing insights on how to reduce their vulnerability and support their resilience. It explores the factors influencing coastal municipalities’ management of relevant hazards to achieve comprehensive multi-hazard risk reduction and adaptation. We do so through a national survey of Canada’s coastal municipalities which assessed experience with hazards, risk perception, hazard prioritization, and the extent and specifics of hazard responses. We characterize the determinants of coastal municipalities’ behaviour and intervening factors, and conduct regression analyses to explain coastal municipalities’ risk perception, hazard prioritization, implementation of management processes for dealing with hazards, and the number of implemented or planned hazard responses. Six key factors were identified that influence hazard responses at the municipal level: experience with hazards; competing priorities; hazard visibility; access to resources (financial and technical capacity) and governance (institutional setting and political capacity). We conclude that municipal hazard responses can be reinforced by increasing the effectiveness of risk communication, promoting participatory processes, providing support for municipalities’ identified needs and priorities, ensuring municipalities have access to relevant information and expertise, and implementing integrated coastal governance and management.  相似文献   

1961—2018年影响深圳市的台风特征分析     

尹宜舟 《气象科学进展》2022,(1)

采用ArcGIS空间分析技术、信息扩散技术等方法,统计分析了1961—2018年影响深圳市的台风特征。结果显示,进入深圳市300 km缓冲区(以下简称缓冲区)的台风频数呈现出明显的下降趋势,概率分析表明深圳市易受强热带风暴及以上等级的台风的影响;深圳市年台风降水量及其占年总降水的比例均呈现出明显的下降趋势,而极大风速呈现出弱的下降趋势;三类登陆台风分析表明,在深圳西侧一带登陆的台风往往会给深圳带来较强的风雨影响,在深圳东侧一带登陆的台风可产生较持续的影响,从深圳以南登陆的台风对深圳市的影响总体上偏小。  相似文献   

基于多源探测资料的“4.12”非典型冰雹特征分析     

孙伟  曹舒娅  沈建 《热带气象学报》2021,37(2):218-232

针对2020年4月12日发生在江苏苏州的一次大范围雷暴大风、局部伴有冰雹的强对流天气过程,基于常州S波段双线偏振多普勒天气雷达、湖州和青浦的单偏振雷达以及再分析资料,详细分析了此次过程的天气背景,不稳定机制、抬升条件和雷达回波及双偏振雷达参量演变特征,并结合双雷达风场反演技术分析超级单体的动力结构及云物理机制。结果表明此次过程发生在高空冷涡南掉、横槽南摆,上下层强烈不稳定的环流背景下,地面有辐合线提供了触发条件。苏南地面附近至600 hPa为θ_se随高度减小的对流不稳定层和0~6 km强烈的垂直风向切变分别为此次过程提供强热力和动力不稳定条件。此次降雹天气过程,雷达回波强度超过50 dBZ,有明显的三体散射、气旋式辐合、高层回波悬垂和强风暴顶辐散等特征;但是VIL和ET都很小,呈现非典型冰雹特征。双线偏振雷达各偏振参量(差分反射率Z_DR、差分相移率K_DP和相关系数CC)也都反映出冰雹云的典型特征:在Z_H大、Z_DR小、CC小的区域出现冰雹,Z_DR值通常为-1.0~0.2 dB,CC值普遍小于0.85。上述双偏振参量特征在强对流短时临近预报和冰雹识别方面具有很强的应用潜力。利用双雷达风场反演技术对降雹时段研究,发现1~5 km各层高度的风垂直切变、辐合的存在,有利于超级单体的发展和加强。双雷达能较好地反演雷暴大风的三维风场精细结构,有助于加深对冰雹云结构的认识进而提高冰雹等强对流天气的预报预警能力。   相似文献   

概率密度匹配方法在我国近海海面10 m风速预报中的应用     

胡海川  赵伟  董林 《热带气象学报》2021,37(1):91-101

海面风速对航运及海上生产作业影响重大,但数值模式对于海面的风速预报仍存在较大误差。为降低数值模式海面10 m风速预报的系统性误差,提高海上大风预报准确率,基于2017—2019年中国气象局地面气象观测资料对ECMWF确定性模式的10 m风场预报结果进行检验评估,并采用概率密度匹配方法对模式误差进行订正。分析结果表明,概率密度匹配方法可有效地改善数值模式10 m风速预报的系统性误差,订正后风速在各个预报时效和风速量级的平均误差均较订正前有所降低。对于大量级风速的预报,经概率密度匹配方法订正后的风速预报的漏报率可减少10%以上。订正后12 h预报时效的8、9级风速预报的平均绝对误差分别由4.15 m/s、5.61 m/s降低至3.12 m/s、4.08 m/s,120 h预报时效的8、9级风速预报的平均绝对误差由7.38 m/s、9.35 m/s减小至6.46 m/s、8.07 m/s。在冷空气、台风大风天气过程中,基于概率密度匹配方法订正后的风速与实况观测更接近,能够为我国近海洋面10 m风速的预报提供更准确的参考。   相似文献   

飑线结构和强度对低层湿度和环境垂直风切变的敏感性研究          下载免费PDF全文

高彦青  孙璐  马旭林  孟泽华  程凯琪 《大气科学学报》2022,45(6):938-947

利用数值模式WRF进行二维飑线理想数值试验。通过改变初始场低层湿度和低层环境垂直风切变探讨了初始环境场对飑线在触发阶段与发展初期结构和强度的影响。低层湿度试验表明,增加低层湿度有利于初始启动阶段对流的发生从而使对流系统强度更强;飑线强度增加,对流上升运动增强,更有利于冷池前沿激发出新生对流单体,系统发展更快;同时激发更多降水,冷池强度增强。低层环境垂直风切变试验表明,在飑线触发阶段,更强的环境垂直风切变使对流主体前倾趋势更大,对对流的触发有阻碍作用;冷池和环境垂直风切变的相互作用被认为是飑线发展的重要机制,基于RKW理论,在飑线发展初期,近地面冷池相对较弱,在更弱的环境垂直风切变作用下更容易使对流结构呈直立状态从而产生更强和更深的上升运动,飑线强度增强。  相似文献   

基于三参数Weibull分布的安徽省年最大风速均一性检验     

温华洋  朱华亮  刘壮  孔芹芹  马文周  陈凤娇 《气象与环境学报》2021,37(2):77-83

以安徽省56个国家级气象站1980—2018年年最大风速序列为研究对象,采用基于三参数Weibull分布的变点检验方法对年最大风速序列均一性进行检验,以郎溪站数据为例,给出了检验和分析的具体过程,最后将该方法检验结果与PMFT法、SNHT法检验结果进行了对比分析。结果表明：56个站点的年最大风速序列均通过Weibull分布检验,而通过正态分布检验的年最大风速序列只有45个,表明年最大风速序列更符合Weibull分布;Weibull法检测出的18个非均一点中有15个得到印证,检验准确率为83.3%,PMFT法检测出的4个非均一点均由迁站造成,检验准确率为100%,SNHT检测出的20个非均一点中有15个得到印证,检验准确率为75%。造成序列非均一的主要原因是台站迁移、仪器换型、仪器高度调整和探测环境变化等;综合比较发现,PMFT法对年最大风速序列非均一点的敏感程度不如Weibull和SNHT,而SNHT法对待检序列要求较高,且检验准确率不及Weibull法,表明Weibull方法在年最大风速序列的均一性检验中更具有优势。  相似文献