共查询到19条相似文献,搜索用时 140 毫秒
1.
冬季局地大气SO_2浓度变化的天气气候学方法研究 总被引:1,自引:1,他引:0
本文根据一种气团客观分类方案,在对研究区域气团类型进行分类的基础上,研究了局地SO_2浓度随气团类型的变化。结果表明,SO_2浓度值作为气团类型的函数变化是显著的;较高的SO_2浓度值出现在那些变胜深、移动慢、持续时间长的反气旋中;个例分析揭示了一次持续时间较长的高SO_2浓度事件的出现与对流层中层的一次中期天气过程的发生、发展、崩溃过程间的良好对应关系。 相似文献
2.
本文根据一种气团客观分类方法,在对研究区域气团类型进行分类的基础上,研究了局地SO2浓度随气团类型的变化。结果表明,SO2浓度值作为气团类型的函数变化是显著的;较高的SO2浓度值出现在那些变性深、移动慢、持续时间长的反气旋中;个例分析了揭示了一次持续时间长较的高SO2浓度事件的出现与对流层中层的一次中期天气过程的发生、发展、崩溃过程间的良好对应关系。 相似文献
3.
4.
对AMT模式的气团回溯轨迹计算方案进行了改进,用该模式在不同的天气条件下,制作了层结曲线预报,并与实况进行了比较,指出该模式对边界层要素有较好的预报能力。 相似文献
5.
分析了长春市气温日变化的气候和天气特征,将统计方法与天气学方法相结合建立了长春市气温逐时预报方法。该方法在考虑不同季节太阳和地面辐射对气温日变化影响的基础上,同时还考虑了气团替换对气温变化的影响,给出了转折性天气气温变化的天气概念模型,可供预报人员参考。对实际预报结果的检验表明,该客观预报方法的准确性和稳定性均显著超过主观经验预报,与日极端气温主观预报水平接近。 相似文献
6.
我们应当努力用统计学理论,使统计气候学发展为气候学的主要理论基础,因为统计气候学在气候数值化过程中所起的重要作用最为重要。气候学和天气学的数值化理论与方法有根本性的差异。短期的天气变化可主要依据确定性动力方程对高层天气变化进行数值模拟,而气候变化的数值模拟应主要依据随机动力模式为宜,因为气候变量是随机变量。在气候应用方面只有地面气候变化规律最为重要,而且长期(逐年、逐月、甚或逐日)气候时空各种变化特征、分型分类以及分区长期预报,也正是统计气候学研究的任务,所以气候学数值化的任务应以统计气候学为主… 相似文献
7.
揭示了2000年6月贵州降水及环流的主要特征,并从天气气候学的观点出发,对强降水的主要气候因子进行分析,结果表明该月降水异常是在极有利的气候背景下发生的。 相似文献
8.
江西省冬季异常气候特征分析 总被引:3,自引:3,他引:3
引入异常度的概念,对江西省48a冬季气候进行分析,建立了冬季异常气候(干湿冷暖)划分的客观标准,并根据天气气候学原理对形成干湿冷暖异常冬季气候的成因进行了对比分析,得出了一些有意义的结果。这些结果在冬季气候预测中有参考价值。 相似文献
9.
分析了宜宾地区产生冰雹天气的大气环流形势及其不同环流型下的能量场结构和特点,天气尺度影响系统的物理机制和相互作用。我区降雹主要产生在西风大槽和阶梯槽型下,由其性质可分为冷锋雹暴和暖气团雹暴两类,冰雹天气的产生需要气团内部具备强不稳定层结,动力扰动触发不稳定能量释放产生强烈的上升运动和有利的环境温湿条件.采用潜在性不稳定度和物理量诊断值定量反映降雹前的气团内部不稳定能量结构和影响系统的强度,能较好地客观反映降雹天气的特点,具有较高的预报准确率。 相似文献
10.
11.
A common method of automated synoptic typing for climatological investigations involves data reduction by principal component analysis followed by the application of a clustering method. The number of eigenvectors kept in the principal component analysis is usually determined by a threshold value of relative variance retained, typically 85% to 95%, under the implicit assumption that varying this relative variance will not affect the resultant synoptic catalogue. This assumption is tested using daily 500-mb geopotential heights over northwest Canada during the winter period (December to February) from 1948 to 2006. Results show that the synoptic catalogue and associated surface climatological characteristics undergo changes for values of relative variance retained over 99%, indicating the typical thresholds are too low and calling into question the validity of performing principal component analysis prior to objective clustering. 相似文献
12.
对我国短期气候业务预测方法的综合分析表明 :我国现有的短期气候业务预测经验和统计方法仍是主要的 ;物理因子和前兆强信号结合天气气候学分析的概念预测模型方法在业务预测中发挥重要作用 ;动力模式预测方法在业务预测中取得一定效果 .随着动力模式的进一步发展 ,短期气候业务预测将逐步走向以动力模式客观预报为指导预报的新阶段 相似文献
13.
J. S. Greene L. S. Kalkstein H. Ye K. Smoyer 《Theoretical and Applied Climatology》1999,62(3-4):163-174
Summary An evaluation of the impacts of weather on pollution, specifically, ozone and total suspended particulates concentration
for Summer, is examined in four cities in the U.S.: Birmingham, Cleveland, Philadelphia, and Seattle. These cities were selected
because of their different climate regimes and their generally good pollutant and meteorological datasets. This paper uses
a synoptic climatological approach, which combines a number of atmospheric factors, to better identify the relationships between
atmospheric pollution and climatological conditions. Synoptic events represent holistic units of atmospheric conditions which
commonly occur at a given locale, and possess specific weather and pollution characteristics. A number of weather variables,
including temperature, are used in the development of a synoptic index, which can be used to identify synoptic events associated
with specific pollution episodes. Results from the analysis illustrate that there is a substantial difference in pollution
loads under different synoptic patterns, and that the cities do have substantially different relationships.
Information from this study could be used to assist in the analysis of the differential impacts of weather and pollution upon
human morbidity. Specific information as to the linkages between the synoptic weather patterns, pollution concentrations,
and human health could be used in the development of weather/health watch-warning systems to alert the public that a synoptic
episode is imminent.
Received September 18, 1998 相似文献
14.
南岭山地高速公路雾区能见度预报系统 总被引:9,自引:4,他引:9
在研究南岭山地浓雾的气候规律,开展了2次多学科综合野外观测,对典型个例进行了天气学分析、雾的宏观结构特征分析、雾的微物理特征分析,在利用数值试验分析了雾生成的物理机制等研究的基础上,研制开发了4种南岭山地京珠高速公路云岩雾区的能见度预报方法,包括:中尺度数值模式产品释用方法、结构预测方法、天气学指标预报方法和动态统计预报方法;并研制了相应的自动化程度高的预测预报系统,与京珠高速公路粤境北段通车同步投入准业务运行,使用雾区路段的5套自动气象站和能见度仪资料,制作的集成预报结果为高速公路行车安全提供服务,经过各种方法的独立预报检验和准业务运行服务的预报结果检验,预报准确率比较高,提供服务的集成预报准确率可达83.3%。 相似文献
15.
16.
17.
R. Suppiah 《Climate Dynamics》1994,10(8):395-405
Synoptic climatological patterns that produce anomalous wet conditions in central Australia during the period from September to April have been studied. The analysis was done by using observed daily rainfall data at a number of stations, wind and mean sea level pressure from the European Centre for Medium Range Weather Forecasts (ECMWF), Tropical Ocean and Global Atmosphere (TOGA) data from 1985 to 1991, and the CSIRO 9-level (CSIR09) global climate model (GCM) simulated data for 1 × CO2 and 2 × CO2 experiments. On the basis of rainfall values above 99.5 percentile in observed and simulated data, wet days have been selected to study the synoptic-scale weather systems that produce anomalous wet events in central Australia. As the vast majority of days in central Australia are dry, the same number of days with no rainfall for both observed and simulated conditions have been selected randomly. The observed synoptic climatological patterns have been compared with the results of the control simulation of CSIRO9. A comparison between CSIRO9 simulated synoptic patterns and observed synoptic patterns reveals that the model fairly well captures the synoptic climatological characteristics which produce anomalous wet and contrasting dry weather conditions during the period from September to April. Under enhanced greenhouse experiments, the main features of the synoptic patterns are intensified both for wet and dry conditions, which result in an increase in extreme weather conditions, an increase in rainfall intensity, a spatial expansion of the heavy rainfall region during wet days, and an expansion of the dry area during dry days. During anomalous wet conditions, the low pressure area is intensified, monsoonal winds and southeasterlies are strengthened and strong wind shear over tropical Australia is simulated. During this condition, the monsoon shear line moves poleward particularly over the Northern Territory. In contrast, during dry conditions, the anticyclonic circulation over the continent is strengthened. 相似文献
18.
对流天气预报中的环境场条件分析 总被引:4,自引:0,他引:4
中尺度对流天气的分析包括以天气型识别和中尺度过程分析为主的主观分析,以及以动力热力物理参数诊断为主的客观分析。利用"配料法"预报的思路,通过诊断有组织的深厚中尺度对流系统发生、发展的4个条件(水汽、不稳定、抬升和垂直风切变),开发了中尺度对流天气的环境场条件分析技术(对流天气图分析和客观物理量诊断技术),并应用于中国国家气象中心的强对流天气预报。以中尺度对流天气的天气图分析方法为例,介绍如何利用高低空观测资料,分析对流天气发生发展的环境场条件;并以数值模式释用为主的强对流特征物理量诊断分析为例,介绍如何动态诊断对流天气的动力热力条件演变。 相似文献
19.
The effect of the high frequency (synoptic) variability of wind and heat fluxes upon the surface ocean off south-central Chile (west coast of South America) is investigated using a regional ocean model. We focus our analysis in austral summer, when the regional wind experiences significant day-to-day variability superimposed on a mean, upwelling favorable flow. To evaluate the nature and magnitude of these effects, we performed three identical simulations except for the surface forcing: the climatological run, with long-term monthly mean wind-stresses and heat fluxes; the wind-synoptic run, with daily wind stresses and climatological heat fluxes; and the full-synoptic run, with daily wind-stresses and daily fluxes. The mean currents and surface geostrophic EKE fields show no major differences between simulations, and agree well with those observed in this ocean area. Nevertheless, substantially more ageostrophic EKE is found in the simulations which include synoptic variability of wind-stresses, impacting the total surface EKE and diffusivities, particularly south of Punta Lavapie (37° S), where the lack of major currents implies low levels of geostrophic EKE. Summer mean SSTs are similar in all simulations and agree with observations, but SST variability along the coast is larger in the runs including wind-stress synoptic variability, suggesting a rather linear response of the ocean to cycles of southerly wind strengthening and relaxation. We found that coastal SST variability does not change significantly in the first tenths of kilometers from the shore when including daily heat fluxes, highlighting the prominent role of wind-driven upwelling cycles. In contrast, in the offshore region situated beyond the 50 km coastal strip, it is necessary to include synoptic variability in the heat fluxes to account for a realistic SST variability. 相似文献