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主因子即备选因子集中与预报对象相关性最好的因子。对与主因子相关性较好而与预报对象相关性较差因子对回归方程效果的影响进行对比试验,并讨论了各部分因子集间的数量关系。 相似文献
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从物理量因子场与云南盛夏（７－８月）大雨作为预报量之间的相关系数计算入手，通过相关场分析来提取因子信息，经过不同组合试验，选出新的预报因子，检验表明，新的组合因子与预报量之间的相关性有明显提高。由此而建立的预报方程有较好的历史拟合率和较稳定的实际预报能力。 相似文献
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从物理量因子场与云南盛夏（7－8月）大雨作为预报量之间的相关系数计算入手，通过相关场分析来提取因子信息，经过不同组合试验，选出新的预报因子。检验表明，新的组合因子与预报量之间的相关性有明显提高。由此而建立的预报方程有较好的历史拟合率和较稳定的实际预报能力。 相似文献
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用达县地区盛夏降水强度指数，计算与其它物理量因子的相关性，通过回归分析，达到预报达县地区盛夏旱涝趋势。 相似文献
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秋冬气压与夏季月雨量分布的关系吕发泰（锡盟气象处）在选择长期预报因子时，不仅需要考虑因子的物理意义，相关性和稳定性，还要注意预报因子和预报对象之间的分布规律，根据它们的分布情况，选用适当的分析方法，才能取得较好预报效果。我台从１９６９年开始应用气压做... 相似文献
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在气象统计预报中,时常涉及到因子和预报对象之间的相关性问题。一般说来,因子与预报对象之间的相关性越好,则因子对预报对象的指示性也越好。然而,由于因子和预报对象之间还有一个相关稳定性的问题,所以,只有在因子和预报对象之间的相 相似文献
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通过对河南省1951～2000年1月份降雪量及其影响因子的分析发现,降雪偏多的主要气候成因与太阳黑子活动高峰期及赤道东太平洋偏低的海温具有明显的相关性,与其它物理因子相关性较差. 相似文献
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我国近30年龙卷风研究进展 总被引：5，自引：3，他引：2
从3方面总结了龙卷风研究成果:①研究概况,最初的龙卷风灾后调查到开展天气气候特征分析至近年来开展龙卷风本体结构、产生机制的探讨,获得了丰硕成果;②研究方法提高,从事实调查到利用统计方法,从利用台站常规观测资料到运用卫星、多普勒雷达、风廓线仪等非常规资料开展分析,近年数值模式WRF、ARPS等也被用来研究龙卷风,研究的方法手段不断得到改进;③龙卷风研究、预报面临的困难和未来展望。 相似文献
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为研究干旱农业区农耕季节气溶胶的基本光学特性,2014年4月利用地面气溶胶移动集成系统在甘肃武威黄羊镇农场开展气溶胶综合观测试验。结果表明,河西走廊黄羊镇农场PM2.5和PM1.0的散射系数以及PM2.5的吸收系数分别为98.2±38.3、74.6±29和8.8±6.3 Mm-1,均小于中东部地区观测值。气溶胶单次散射反照率为0.90±0.03,PM2.5和PM1.0的Angstrom指数分别为1.31±0.29和2.10±0.24。散射系数和吸收系数的日变化具有明显的双峰特征,单次散射反照率在散射系数出现峰值的时间段出现谷值。黄羊镇农场受人为气溶胶影响较大,西、西南和东南方向来的气溶胶散射系数和吸收系数值较大,西北方向传输过来的气溶胶主要是农业生产活动产生的。 相似文献
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根据武汉市1951—2007年间年平均、最高、最低气温与8类年极端天气日数的序列,计算分析其变化趋势及年平均气温与极端天气日数的相关性,引入格兰杰因果性检验法,探讨气候变暖与极端天气事件之间的因果关系。结果发现:(1)近57年来武汉市年平均最低气温增幅为0.45℃/10a,明显高于年平均最高气温0.19℃/10a的增幅,可见气候变暖主要是由夜间气温升高所致;(2)高温和闷热天气事件为增多趋势,其中闷热天气事件最明显,达到2.8 d/10a,而年雷暴、降雪、低温、大风、雾日则均为下降趋势,雷暴、雾和低温事件降幅明显,每10年减少3.0 d、4.0 d和2.1 d。大风和降雪事件,每10年减少1.8 d和1.5 d。暴雨事件波动幅度较小。(3)年平均气温与当年及超前、滞后1～2年的极端天气事件具有高相关性;(4)格兰杰因果性检验结果发现,气候变暖是闷热天气增多和降雪事件减少的原因,同时亦是大风和低温减少的结果。这种因果关系的存在对极端天气事件预测和预估有重要的价值。 相似文献
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城市气象研究进展 总被引：5，自引：0，他引：5
中国数十年来在城市气象研究这一新兴学科领域开展了大量研究并获得了多方面的丰硕成果。文中从城市气象观测网与观测试验、城市气象多尺度模式、城市气象与大气环境相互影响、城市化对天气气候的影响等4个方面论述了城市气象的主要研究进展:中国各大城市已建立或正在完善具有多平台、多变量、多尺度、多重链接、多功能等特点的城市气象综合观测网;北京、南京、上海等地开展了大型城市气象观测科学试验,被世界气象组织列入研究示范项目;成功开展了风洞实验、缩尺度外场实验研究;建立了多尺度城市气象和空气质量预报数值模式,并应用于业务;在城市热岛效应、城市对降水影响、城市气象与城市规划、城市化对区域气候及空气质量的影响、城市气象与大气环境相互作用等研究领域取得长足进展。最后指出,未来需要重点从新观测技术及观测资料同化应用、城市系统模式研究、城市化对天气气候的影响机理、城市化对大气环境和人体健康的影响、城市水文气象气候与环境综合服务等方面开展科学研究与应用,为中国城市化、生态文明建设、防灾减灾和应对气候变化等国家需求提供科技支撑。 相似文献
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Trends in Temperature Extremes in Association with Weather-Intraseasonal Fluctuations in Eastern China 总被引：3，自引：0，他引：3
Trends in the frequencies of four temperature extremes (the occurrence of warm days, cold days, warm nights and cold nights) with respect to a modulated annual cycle (MAC), and those associated exclusively with weather-intraseasonal fluctuations (WIF) in eastern China were investigated based on an updated homogenized daily maximum and minimum temperature dataset for 1960–2008. The Ensemble Empirical Mode Decomposition (EEMD) method was used to isolate the WIF, MAC, and longer-term components from the temperature series. The annual, winter and summer occurrences of warm (cold) nights were found to have increased (decreased) significantly almost everywhere, while those of warm (cold) days have increased (decreased) in northern China (north of 40°N). However, the four temperature extremes associated exclusively with WIF for winter have decreased almost everywhere, while those for summer have decreased in the north but increased in the south. These characteristics agree with changes in the amplitude of WIF. In particular, winter WIF of maximum temperature tended to weaken almost everywhere, especially in eastern coastal areas (by 10%–20%); summer WIF tended to intensify in southern China by 10%–20%. It is notable that in northern China, the occurrence of warm days has increased, even where that associated with WIF has decreased significantly. This suggests that the recent increasing frequency of warm extremes is due to a considerable rise in the mean temperature level, which surpasses the effect of the weakening weather fluctuations in northern China. 相似文献
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由于全球变暖,极地地区的气候经历了明显的变暖放大.在本项研究中,我们根据CMIP6模式的三种变暖情景(SSP1-2,6,SSP2-4.5和SSP5-8.5)下,极地放大变化对各个反馈机制(包括普朗克,温度递减率,云,水蒸气,反照率反馈,CO2强迫,海洋热吸收和大气热传输)的响应进行了分析.结果表明,通过用“辐射核”方法量化不同反馈机制对地表温度的增温贡献,北极放大(AA)强于南极放大(ANA),由温度递减率反馈主导,其次是反照率和普朗克反馈.此外,海洋的热吸收导致冬季比夏季有更强的极地变暖.在冬季,温度递减率反馈主导了AA大于ANA.AA和ANA的模式间差异随着全球变暖的增强而减小. 相似文献
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我国东部地区冬季模式边界层探空效果评估 总被引：1，自引：0，他引：1
应用中尺度气象模式MM5对2006年和2007年12月东部地区进行逐日模拟,并用地面常规观测资料及南京和安庆12h一次的逐日探空资料对模拟的地面及边界层内气象要素进行检验,计算地面和边界层内不同高度的温度、湿度、风向和风速等要素的多种常用统计参数;并分别评估雾发生前和发生时边界层探空的模拟效果。结果表明:(1)MM5模式模拟的地面温度和湿度均较理想,但风速误差较大。温度、相对湿度、风速的观测与模拟的偏差概率分布均呈近正态分布,峰值中心分别为-1.52℃、4.59%和1.92m·s-1,白天模拟效果优于夜间。(2)以南京、安庆两站为例,模拟的08:00(北京时,下同)和20:00边界层内探空基本可靠,但20:00的效果比08:00好;模拟效果均随高度上升而变好;且南京站边界层内温度、湿度的模拟效果优于安庆站,但安庆站风的模拟效果优于南京站。(3)以南京站为例,雾发生前和发生时温度、湿度模拟效果较平均情况差,风速模拟较其他模拟时段无明显变化。(4)南京、安庆冬季近地层逆温发生频率都比较高,常见多层逆温,MM5模式能再现近地层逆温,但有高估的倾向,且对边界层中上部逆温模拟效果不佳。此外,敏感性试验的结果表明,模拟方案中地面负的温度偏差不是由近地层高垂直分辨率所致。 相似文献
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Recent advances in monsoon studies in China 总被引：8，自引：0，他引：8
This review provides a synopsis of the major progress that has been made in monsoon studies in China and to further bridge the gap between the Chinese and international meteorological community. It consists of seven major sections. After the introduction, the second section begins with the global monsoon systems and their seasonal variation, based on some new methods proposed in recent years. Besides, some major intraseasonal features of East Asian monsoon, including the onset of South China Sea summer monsoon are discussed. In the third section, we review the interactions between ENSO and the East Asian monsoon, focusing in particular on the results of Chinese meteorologists that indicate the influence of ENSO on the East Asian summer monsoon(EASM) is obviously different from that on the tropical monsoon. Besides the tropical Pacific,other ocean basins, such as the Indian Ocean and the Atlantic Ocean, are also important to the East Asian monsoon, and this topic is discussed in the fourth section. In the fifth section, we address the role of land surface processes in East Asian monsoon. For example, we describe work that has shown more snow cover in spring on the Tibetan Plateau is followed by a weakened EASM and more summer rainfall in the Yangtze River valleys. The sixth section focuses on the influence of atmospheric circulation in the Southern Hemisphere(SH) on EASM, demonstrating how the signal from the SH is likely to provide new clues for the seasonal forecasting of summer rainfall in China. Finally, in the seventh section, we concentrate on the interdecadal variations of EASM. In particular, we look at a significant interdecadal variation that occurred at the end of the 1970 s, and how our understanding of this feature could affect forecasting ability. 相似文献
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FAN Li-Jun 《大气和海洋科学快报》2014,(4):304-308
A number of recent studies have examined trends in extreme temperature indices using a linear regression model based on ordinary least-squares. In this study, quantile regression was, for the first time, applied to examine the trends not only in the mean but also in all parts of the distribution of several extreme temperature indices in China for the period 1960-2008. For China as a whole, the slopes in almost all the quantiles of the distribution showed a notable increase in the numbers of warm days and warm nights, and a significant decrease in the number of cool nights. These changes became much fas- ter as the quantile increased. However, although the number of cool days exhibited a significant decrease in the mean trend estimated by classical linear regression, there was no obvious trend in the upper and lower quantiles. This finding suggests that examining the trends in different parts of the distribution of the time-series is of great importance. The spatial distribution of the trend in the 90th quantile indicated that there was a pronounced increase in the numbers of warm days and warm nights, and a decrease in the number of cool nights for most of China, but especially in the northern and western parts of China, while there was no significant change for the number of cool days at almost all the stations. 相似文献