共查询到20条相似文献，搜索用时 187 毫秒
1.
2.
应用Lamb-Jenkinson大气环流分型法对渤海海峡1979—2013年逐日海平面气压场进行大气环流客观分型,分析了渤海海峡大风天气与大气环流型的关系;以长岛气象站在渤海海峡大风天气中的指示作用为基础,分析了主要环流型下大风天气的气候特征。结果表明：渤海海峡大风天气以平直环流型为主,偏北型明显多于偏南型;春（夏）季是发生大风天气最多（少）的季节,以西南（SW）型出现频率最高,秋、冬季大风天气的环流型频率分布基本相同,均以偏北型为主;不同环流型下出现大风天气的概率及大风天气的气候特征也有明显不同。 相似文献
3.
该文利用三明市1960-2010年共51 a的冰冻天气记录和历史气象资料,着重分析了三明市冰冻天气时空分布及气候特征,并对冰冻天气进行天气型分析.结果表明：三明市冰冻天气发生时间集中在11月—次年2月,从冰冻频率和强度上看,1月和2月均高于11月和12月.三明市冰冻天气分布主要集中在西北部,东南部基本无冰冻天气（除高海拔山区）,冰冻天气中心位于建宁.51 a来三明市平均冰冻日数及站次表现为显著地减少趋势,其气候倾向减少率为1.0 d/10 a.根据500 hPa乌拉尔山槽脊和南支槽的活跃程度,可将三明市冰冻天气分为3种类型,即北脊南槽型、乌拉尔山脊型、横槽南支型. 相似文献
4.
5.
为提高相关业务技术人员的科技论文选题能力及其写作质量，给出天气气候诊断型论文的定义，指出此型论文的研究对象与研究目的，论述了作为天气气候诊断型论’文研究对象的天气个例的罕见性、极端性、特殊性、危害性特征；依据天气个例数量，将天气气候诊断型论文分为单个例诊断分析型、双个例诊断分析型和多个例诊断分析型三种类型，在此基础上，细分为若干小类，并结合论文实例，分别对实现其选题的前提和着眼点进行了探讨。 相似文献
6.
7.
8.
本文通过对济南近十年大风资料的分析和统计，总结了春季西南大风的气候概况和天气特征，并将影响系统分为低压型、高压后部型和南高北低型，依照天气学观点找出预报因子，采用０－１型分析中的条件频率差方法建立预报方程。 相似文献
9.
综合极端气候指数的定义和趋势分析 总被引：6，自引：1，他引：5
综合极端气候指数对于极端气候变化监测、整体认识区域极端气候变化趋势及其原因和影响,具有实际意义。根据中国常年极端气候特点和不同种类极端气候事件的经济社会影响,选取全国平均高温日数、低温日数、强降水日数、沙尘天气日数、大风日数、干旱面积百分率和登陆热带气旋频数等7种极端气候指标,定义两个综合极端气候指数,分别为7种极端气候指标简单(等值权重)合成的综合指数I和加权(差异权重)合成的综合指数II。综合指数II主要依据各种极端气候事件引发的灾害严重程度及其社会影响大小,分别确定其对应指标的相对重要性和权重系数。分析结果表明:1956～2008年,综合指数I序列表现出明显的下降趋势,说明中国地区常见的极端气候事件总体有不断减少、减弱的趋势;同期综合指数II序列没有表现出明显的升降趋势变化,说明对中国地区具有重大经济和社会影响的极端气候事件频率总体上没有发生明显变化。就各个单项极端气候指数变化来看,全国平均年高温日数、强降水日数和干旱面积百分率呈上升趋势,但除高温日数外,其他指数趋势变化均不显著;全国平均年低温日数、沙尘天气日数和大风日数呈下降趋势,且趋势性均很显著;登陆中国大陆的热带气旋频数有所减少,但趋势不很明显。因此,在全球气候显著变暖的半个多世纪内,中国地区多数常见的极端气候事件发生频率,或者显著减少,或者变化不明显;而对全国经济和社会具有重大影响的主要极端气候事件,其频率总体上未见明显趋势变化。 相似文献
10.
11.
利用2014—2016年辽宁省冬季高速公路事故记录,将多要素逐日气象观测数据与事故数据按照日期进行匹配,分析气象条件引发高速事故的空间分布特征。数据挖掘分析首先利用两步聚类方法确定辽宁地区冬季天气类型数量,再通过K-means方法对气象数据进行聚类处理。采用随机森林方法对不同天气类型搭建高速公路交通事故分类模型,并分析模型中气象要素的特征重要性。结果表明：受气象条件影响的高速事故数量辽南地区最多,其次是辽西地区,辽东、辽北地区占比较低。辽宁冬季天气可以分为四种类型,根据气象要素数据结构总结出的天气特征分别为：当日出现降水、前一日出现降水、寒冷干燥、潮湿回暖。有明显降水特征天气类型的事故率超过七成,降温、升温天气类型的事故率在两成左右。随机森林方法对前一日出现降水、寒冷干燥两种天气类型的分类精度更高,模型泛化能力也更好。4种天气类型中气象要素的特征重要性有明显差异,最高地温要素在事故高发天气类型中特征重要性排第1位,在潮湿回暖天气类型排第3位,对于冬季辽宁地区高速公路交通安全影响高于其他要素。 相似文献
12.
C. Michailidou P. Maheras A. Arseni-Papadimititriou F. Kolyva-Machera C. Anagnostopoulou 《Theoretical and Applied Climatology》2009,97(1-2):179-194
A discriminant analysis is applied in order to determine the relationships between circulation types in the middle troposphere and prevailing weather types over two major Greek cities, Athens and Thessaloniki. In order to describe the synoptic conditions, an automatic classification scheme for the Greek region is used. For each circulation type identified (14 in total), several meteorological parameters at the 500 hPa level are calculated such as geopotential heights and their anomalies, temperature and relative vorticity. Weather group-types that reflect the conditions at the surface, were previously defined using a two-step cluster analysis. These types result from a combination of five meteorological parameters—maximum temperature, precipitation amount, relative humidity, wind velocity and sunshine duration. The study period is 43 years long (1958–2000) and is restricted to the cold and wet period of the year, from December until March. For Athens, six weather types are developed, whereas for Thessaloniki five are produced. By means of a stepwise discriminant analysis (DA) model, the most important variables from the 500 hPa level are found and are used to generate the necessary functions that can discriminate weather types over the two stations. The aim of the present study is first to discriminate weather types effectively and to identify the most important discriminating variables, and second, to connect these weather types to elements of the prevailing synoptic pattern, through mathematical functions provided by DA. The results of the evaluation of the aforementioned procedure are considered to be very satisfactory. 相似文献
13.
14.
C. Michailidou P. Maheras A. Arseni-Papadimititriou F. Kolyva-Machera C. Anagnostopoulou 《Theoretical and Applied Climatology》2009,97(1-2):163-177
This paper presents a method for grouping weather types that occur over an area, which combines meteorological parameters, reflecting air mass characteristics at the surface, with synoptic conditions prevailing over an area. Five quantitative meteorological parameters are used in the procedure: temperature, precipitation, relative humidity, wind velocity and sunshine duration. In addition, two qualitative variables related to the prevailing circulation type and whether it is cyclonic or anticyclonic are also included. The study period is 43 years (1958–2000) and is restricted to the cold and wet sub-period of the year, December–March. Weather types are defined using a relatively new method of cluster analysis, two-step cluster analysis, which allows the simultaneous use of both quantitative and qualitative variables. The aim of the present study is to distinguish primary weather patterns so that the investigation into the relationship between weather patterns and circulation types will be more effective. For Athens, six weather types are created, whereas for Thessaloniki five are produced. For both stations, only two weather types are related to anticyclonic situations. The majority of the identified weather types correspond to a distinctive and well-defined synoptic situation. Each weather type differs from the others, not only in terms of the circulation conditions referring to it, but also with reference to meteorological variables such as temperature and precipitation. The results of the evaluation of the aforementioned procedure are considered to be highly satisfactory. 相似文献
15.
16.
17.
Summary An attempt has been made to relate a large-scale airflow classification to the local weather at two stations in Estonia.
To describe the features of the general circulation over Europe, the large-scale circulation patterns (Grosswetterlagen) of the German Weather Service have been chosen. Daily precipitation and temperature deviations from the monthly mean in
P?rnu and Tartu for 1961–1993 have been used. It can be said that the weather in Estonia shows a good relationship with the
general circulation types (Zirkulationsformen) that are defined by means of the Grosswetterlagen. Zonal circulation brings to Estonia wet weather that in winter is warmer than average and in summer cooler than average.
Mixed circulation is associated with warmer winters and average summers. Meridional circulation brings cold winters and variable
weather in summer. To explain the large dispersion of values of meteorological elements within any one circulation type, a
more detailed analysis of the relationships between circulation patterns and meteorological situation in Estonia is needed.
Received June 17, 1998 Revised January 13, 1999 相似文献
18.
19.
介绍了《山西省大同市专业专项气象预报系统》的研制及应用,包括系统主要技术要点,主要内容、系统运行情况,还介绍了专业专项气象指标的分析应用及用数值产品为基础多种预报方法相结合制作各种专业专项气象预报。 相似文献