利用中国华东六省一市13个探空站1961-2017年高空温度数据,对850 h Pa、500 h Pa、200 h Pa高空温度的时间变化特征和空间变化特征进行分析,结果表明:1961-2017年中国华东区域对流层中下层增温趋势明显,向上增温趋势减弱,对流层顶增温...利用中国华东六省一市13个探空站1961-2017年高空温度数据,对850 h Pa、500 h Pa、200 h Pa高空温度的时间变化特征和空间变化特征进行分析,结果表明:1961-2017年中国华东区域对流层中下层增温趋势明显,向上增温趋势减弱,对流层顶增温趋势有所增强。850 h Pa、500 h Pa温度的年代际变化均呈现出先降低后升高的趋势,而200 h Pa温度的年代际变化则呈现持续升高的趋势。秋、冬季在各个层次上均为显著的增温趋势,冬季的增温趋势明显大于其他季节,500 h Pa春季和200 h Pa夏季有微弱的降温趋势。不同层次年平均气温的空间分布均有明显的南北差异,且随着高度的增加,南北平均温差先增大后减小。850 h Pa、500 h Pa年平均温度的空间变化趋势一定程度上呈现出华东沿海地区增温趋势大于内陆的特征,200 h Pa则呈现华东南部的增温趋势大于北部的特征。850 h Pa各季节呈现出中国华东沿海地区增温、内陆增温趋势不如沿海地区或内陆呈现降温趋势,500 h Pa的春季和200 h Pa的夏、秋季则呈现出中国华东南部地区增温、北部地区降温的趋势。展开更多
通过直接数值求解Navier-Stokes方程,研究了入流激励下可压缩剪切层中Kelvin-Helmholtz(KH)涡结构的响应特性,结果清晰地展示了KH涡的独特演化方式.基于流动可视化数据,采用两点相关性分析获得了流场拟序结构的空间尺寸和结构角分布.通...通过直接数值求解Navier-Stokes方程,研究了入流激励下可压缩剪切层中Kelvin-Helmholtz(KH)涡结构的响应特性,结果清晰地展示了KH涡的独特演化方式.基于流动可视化数据,采用两点相关性分析获得了流场拟序结构的空间尺寸和结构角分布.通过分析不同激励频率下涡结构的动态特性,揭示了入流激励下可压缩剪切层中KH涡结构的独特演化机理.研究结果表明,低频入流激励(f=5 k Hz)下KH涡尺寸在远场区域达到饱和后呈现锁频状态,KH涡量厚度稳定在12-14 mm之间;与自由剪切层涡结构通过配对合并的方式实现生长的机理不同,低频入流激励下剪切层的发展是通过中间涡核顺时针吞噬KH不稳定波诱导的一串外围小涡结构来实现生长.此外,针对高频激励(f=20 k Hz)下的剪切层流动,研究了涡结构特性和入流激励参数之间的定量关系,发现均匀分布涡结构的尺寸近似等于对流速度与入流激励频率之比.展开更多
[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statisti...[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statistical analysis of the O3 concentration near the ground in Pudong District of Shanghai from 2006 to 2008, by considering meteorological condition, a kind of simple and practical new method suiting for forecast of the O3 concentration and pre-warning of the high-concentration O3 pollution event in whole year was established. [Result] Meteorological condition had obvious influence on O3 concentration near the ground. O3 concentration was the biggest in sunny day, followed by cloudy day. O3 concentration near the ground had typical seasonal change characteristics, and high value mainly happened in summer. Meteorological condition generating high-concentration O3 included sunny day, strong UV radiation, low relative humidity, high temperature and small wind speed, etc. By surveying historical weather chart, 10 kinds of main weather situations affecting Shanghai were summed. Under each weather situation, occurrence probability of the high-concentration O3 near the ground and average O3 concentration were conducted statistics. We found that occurrence probability of the high-concentration O3 was the biggest under northwest side of the subtropical high type, followed by internal type of the subtropical high. By introducing HPPI and WDI and comprehensively considering various meteorological factors, forecasting equation of the O3 concentration was established based on stepwise regression. The equation had good fitting effect and predictability on the daily maximum O3 concentration. [Conclusion] The method also could provide reference for O3 forecast in other areas.展开更多
基于上海地区2006~2016年逐日PM10浓度数据以及同期气象要素(风、气温等)、大气稳定度、逆温数据和高空大气环流数据,分析了2007~2016年上海地区颗粒物浓度变化特征和冬季气候背景的异同,并建立多元线性逐步回归方程,同时选取颗粒物高...基于上海地区2006~2016年逐日PM10浓度数据以及同期气象要素(风、气温等)、大气稳定度、逆温数据和高空大气环流数据,分析了2007~2016年上海地区颗粒物浓度变化特征和冬季气候背景的异同,并建立多元线性逐步回归方程,同时选取颗粒物高浓度年份和低浓度年份,对比分析高空大气环流形势的差异.结果表明,上海地区颗粒物年平均浓度呈现波动式下降趋势,而冬季呈现出两头高、中间低形态.PM10与平均风速、20:00混合层高度负相关,与偏西北风、20:00稳定类、20:00逆温的出现频率及平均气温正相关.当冬季我国北部500 h Pa高度场合成为正距平,容易形成暖冬,从而引起高浓度颗粒物污染;而当500 h Pa高度场为负距平,容易引起冷空气频繁南下,导致气温偏低,容易造成PM10浓度相对偏低.850 h Pa风场异常为偏东风,且风速偏大,容易造成PM10浓度相对偏低.展开更多
文摘利用中国华东六省一市13个探空站1961-2017年高空温度数据,对850 h Pa、500 h Pa、200 h Pa高空温度的时间变化特征和空间变化特征进行分析,结果表明:1961-2017年中国华东区域对流层中下层增温趋势明显,向上增温趋势减弱,对流层顶增温趋势有所增强。850 h Pa、500 h Pa温度的年代际变化均呈现出先降低后升高的趋势,而200 h Pa温度的年代际变化则呈现持续升高的趋势。秋、冬季在各个层次上均为显著的增温趋势,冬季的增温趋势明显大于其他季节,500 h Pa春季和200 h Pa夏季有微弱的降温趋势。不同层次年平均气温的空间分布均有明显的南北差异,且随着高度的增加,南北平均温差先增大后减小。850 h Pa、500 h Pa年平均温度的空间变化趋势一定程度上呈现出华东沿海地区增温趋势大于内陆的特征,200 h Pa则呈现华东南部的增温趋势大于北部的特征。850 h Pa各季节呈现出中国华东沿海地区增温、内陆增温趋势不如沿海地区或内陆呈现降温趋势,500 h Pa的春季和200 h Pa的夏、秋季则呈现出中国华东南部地区增温、北部地区降温的趋势。
文摘通过直接数值求解Navier-Stokes方程,研究了入流激励下可压缩剪切层中Kelvin-Helmholtz(KH)涡结构的响应特性,结果清晰地展示了KH涡的独特演化方式.基于流动可视化数据,采用两点相关性分析获得了流场拟序结构的空间尺寸和结构角分布.通过分析不同激励频率下涡结构的动态特性,揭示了入流激励下可压缩剪切层中KH涡结构的独特演化机理.研究结果表明,低频入流激励(f=5 k Hz)下KH涡尺寸在远场区域达到饱和后呈现锁频状态,KH涡量厚度稳定在12-14 mm之间;与自由剪切层涡结构通过配对合并的方式实现生长的机理不同,低频入流激励下剪切层的发展是通过中间涡核顺时针吞噬KH不稳定波诱导的一串外围小涡结构来实现生长.此外,针对高频激励(f=20 k Hz)下的剪切层流动,研究了涡结构特性和入流激励参数之间的定量关系,发现均匀分布涡结构的尺寸近似等于对流速度与入流激励频率之比.
基金Supported by Special Item of the Science Research for Public Service Industry (Meteorology) ,China (GYHY201206027,GYHY200906026)
文摘[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statistical analysis of the O3 concentration near the ground in Pudong District of Shanghai from 2006 to 2008, by considering meteorological condition, a kind of simple and practical new method suiting for forecast of the O3 concentration and pre-warning of the high-concentration O3 pollution event in whole year was established. [Result] Meteorological condition had obvious influence on O3 concentration near the ground. O3 concentration was the biggest in sunny day, followed by cloudy day. O3 concentration near the ground had typical seasonal change characteristics, and high value mainly happened in summer. Meteorological condition generating high-concentration O3 included sunny day, strong UV radiation, low relative humidity, high temperature and small wind speed, etc. By surveying historical weather chart, 10 kinds of main weather situations affecting Shanghai were summed. Under each weather situation, occurrence probability of the high-concentration O3 near the ground and average O3 concentration were conducted statistics. We found that occurrence probability of the high-concentration O3 was the biggest under northwest side of the subtropical high type, followed by internal type of the subtropical high. By introducing HPPI and WDI and comprehensively considering various meteorological factors, forecasting equation of the O3 concentration was established based on stepwise regression. The equation had good fitting effect and predictability on the daily maximum O3 concentration. [Conclusion] The method also could provide reference for O3 forecast in other areas.
文摘基于上海地区2006~2016年逐日PM10浓度数据以及同期气象要素(风、气温等)、大气稳定度、逆温数据和高空大气环流数据,分析了2007~2016年上海地区颗粒物浓度变化特征和冬季气候背景的异同,并建立多元线性逐步回归方程,同时选取颗粒物高浓度年份和低浓度年份,对比分析高空大气环流形势的差异.结果表明,上海地区颗粒物年平均浓度呈现波动式下降趋势,而冬季呈现出两头高、中间低形态.PM10与平均风速、20:00混合层高度负相关,与偏西北风、20:00稳定类、20:00逆温的出现频率及平均气温正相关.当冬季我国北部500 h Pa高度场合成为正距平,容易形成暖冬,从而引起高浓度颗粒物污染;而当500 h Pa高度场为负距平,容易引起冷空气频繁南下,导致气温偏低,容易造成PM10浓度相对偏低.850 h Pa风场异常为偏东风,且风速偏大,容易造成PM10浓度相对偏低.
