短期集合预报技术在梅雨降水预报中的试验研究

数值预报的误差来源于初始场和模式的误差,集合预报技术是减小这些误差的有效方法。该文以MM5模式作为试验模式框架,模式的积云参数化方案分别取Anthes-Kuo、Grell、Kain-Fritsch和Betts-Miller方案,边界层参数化方案分别取MRF和Eta方案,通过组合4种积云参数化方案和两种边界层参数化方案产生8个集合成员,对1999年华东地区梅雨期间3个降水个例进行48 h集合预报试验。结果显示不同集合成员的预报结果各不相同,积云参数化方案对降水的影响比边界层参数化方案对降水的影响大;不同集合成员预报降水的偏差也各不相同,大多存在湿偏差,量级小的降水的湿偏差程度比量级大的降水的湿偏差程度小;对于不同个例,各成员中预报效果相对较好的成员是不同的,集合平均后可以得到一个比较稳定的预报结果;从集合预报结果中还能得到客观化和定量化的降水概率预报,它能对可能发生的天气现象发出信号。     

新疆巴楚凸起奥陶系潜山气藏形成的主要控制因素及区域预测

塔里木盆地巴楚凸起奥陶系潜山天然气勘探前景广阔,已发现和田河气田和山1井气藏。该区烃源岩好,储层盖层组合匹配完好,圈闭面积大,是有利的油气勘探区域。通过对和田河气田和山1井气藏特征的综合研究,发现气藏的形成主要受控于烃源岩、断裂、不整合面和岩溶作用,只要4个控制因素相匹配,就可形成大型天然气藏。结合国内外碳酸盐岩气藏的勘探实践,对该区碳酸盐岩气藏的形成和分布规律进行了总结,其规律是：沿古隆起分布,沿断裂带分布,沿不整合面分布,近烃源岩分布。根据潜山气藏的主要控制因素和分布规律,该区应选择志留系和奥陶系尖灭线以南以西的和山1井与玛参1井一线和色力布亚断裂带为主要勘探目标,应对岩溶较为发育的卡拉沙依断裂带进行系统研究。     

哈密地区南部一次大降水机制分析

对造成哈密南部"2000·6·23"大降水的主要影响系统南疆低槽、北方冷空气、中低层切变等进行了描述,并从热力因素、动力因素两方面对其特征予以剖析,得到哈密南部大降水预报的某些着眼点.     

The Major Snow Avalanche Cycle of February 1986 in the Western United States

Snow avalanches are a significant hazard in mountainous environments around the world. This paper investigates the major February 1986 avalanche cycle that occurred in the western United States, and broadly analyzes the avalanche, snowpack, and weather conditions at twenty sites. These analyses suggest that the avalanche cycle resulted from the interaction of a relatively `normal' snowpack with an exceptional storm event, which was particularly noteworthy for the amount of precipitation it produced. Composited 500-hPa anomaly maps show the event resulted from an uncommonly persistent blocking pattern that resulted in a strong zonal flow and copious moisture being funneled over the western United States. Understanding severe and widespread avalanche cycles may improve our long-term forecasting of these events, and help mitigate theresulting avalanche activity.     

Air Quality as a Meteorological Hazard

Meteorological hazards are usually considered to be tropical cyclones, droughts, hail-storms, severe storms and their effects such as tsunamis, storm surges, wildfire, and floods. Urban air pollution is not normally considered to be a meteorological hazard. This view has arisen because the causes of urban air pollution – industrial and motor vehicleemissions – are not meteorological in nature. Air pollution episodes, however, are sporadic in nature and their occurrence depends on a particular combination of meteorological factors. This is true even in megacities such as Mexico City, Manila, and Los Angeles that have acquired a reputation for polluted air. Analyses of air pollution episodes and hospital admissions from many countries indicate that thereis a significant increase in morbidity and mortality as a result of such episodes.Time-series studies undertaken in Sydney have shown that particulate matter, ozone and nitrogen dioxide are the pollutants that are primarily responsible for adverse health effects in that city.Air pollution, and in particular particulate matter, is believed to be responsible for just under 400 premature deaths per year in Sydney alone. This death rate is over twenty times larger than deaths due to other meteorological hazards. Part of the reason for the low death rate for the more traditional meteorological hazards is that the provision of high quality numerical weather prediction, coupled with modern communications technology, has enabled emergency service personnel to take appropriate action.Air quality forecasting systems can play an important role in mitigating the adverse effects of air pollution. The forecasts will affect the behaviour of susceptible individuals, and thus reduce adverse health effects. The outputs from forecasting systems can also be used to provide improved estimates of the total exposure to air pollutants of the inhabitants who areat risk. Such improved estimates can then be used in conjunction with longitudinal studies ofhealth effects to obtain better understanding of the complex interaction between air quality and health.     

GM（1，1）优化模型在滑坡预测预报中的应用

灰色模型在社会科学、自然科学的许多方面已得到广泛的应用，并取得了一系列重大成果。在斜坡(滑坡)地质灾害研究方面，灰色模型多用于斜坡(滑坡)变形的中长期预测预报，且精度较高；但对滑坡短临预测预报精度较差，甚至不能适用，有待改进。滑坡变形预测预报的实际算例表明，以优化灰色模型背景值为基础的优化GM(1，1)模型。具有对建模结果进行优化的能力，即能用于斜坡变形的中长期预测预报，又能适于滑坡短临预测预报。且都能获得较高的模拟和预测精度。应用传统线性GM(1，1)模型和非线性Verhulst模型进行对比分析，检验了优化GM(1，1)模型的正确性和较广泛的适用性。     

用T42产品试作安徽12-36小时暴雨预报

采用逐步回归和三级判别方案，以Ｔ４２４８小时预报资料代替实况诊断量作汛期安徽分区暴雨预报。通过１９９３年和１９９４年试验结果表明：（１）两方案预报暴雨的ＣＳＩ评分为０．３０—０．７１，对省级分区暴雨预报有一定的参考价值；（２）逐步回归方案的预报效果优于三级判别；（３）丰梅年Ｔ４２模式的预报效果好干枯梅年。     

湖北省梅雨期分级降水预报试验

以武汉中心气象台日常业务降水预报项目为研究对象，选择梅雨期１２－３６小时预报时段，以灰色系统理论的生成函数为基础，运用灰色预测模型将ＬＡＦＳ模式等降水量预报集成，制作了武汉单站降水量分级（弱降水，中等强度降水和强降水）预报。运用回归分析方法，将ＬＡＦＳ资料的降水量预告场订正到湖北省５个自然区，制作湖北省区域降水分级预报。经过１９９３年、１９９４年准业务试验，获得了较好的效果。     

春季低温阴雨中期预报系统

该系统是以数值预报产品为基础而建立的春季低温阴雨中期预报业务系统。系统含较完善的低温阴雨和连晴天过程资料，采用逐步回归、逐步判别、相似预报等方法，将数值预报产品与天气学原理及预报员经验相结合，实现了从资料采集到预报制作自动化和客观化。系统采用模块结构和批处理技术，操作简便，资料和图形显示快捷。经３年试报结果表明，系统对春季低温阴雨有较强的预报能力，在实际预报服务中取得显著的社会经济效益。     

修正的ECMWF质量通量积云参数化方案的预报试验

用一个有限区域业务预报模式，以１９９５年７—８月西北地区几次大范围的降水天气过程为试验个例，对经过修改的ＥＣＭＷＦ质量通量积云参数化方案和模式中的原Ｋｕｏ型积云参数化方案进行了共１３例４８ｈ的批量对比预报试验。结果显示：质量通量方案能给出比Ｋｕｏ型方案更合理的积云降水落区；质量通量方案对模式预报≥１０．０ｍｍ的降水有一定的改进，并提高了各种降水等级的预报效率评分值