基于地面观测与CrIS卫星反演的数据,分析了我国2015年9月—2016年8月的大气氨(NH_(3))浓度在时空上的变化特征,并评估了这两类数据之间存在的差异.结果表明:基于CrIS卫星反演的数据能够很好地识别我国NH_(3)浓度在时空上的变化趋势,但...基于地面观测与CrIS卫星反演的数据,分析了我国2015年9月—2016年8月的大气氨(NH_(3))浓度在时空上的变化特征,并评估了这两类数据之间存在的差异.结果表明:基于CrIS卫星反演的数据能够很好地识别我国NH_(3)浓度在时空上的变化趋势,但同地面观测相比,存在数值上的低估.我国的NH_(3)浓度总体上呈现出“夏高冬低”的特点.就空间分布而言,华北、华东和中南地区是我国目前NH_(3)浓度相对较高的地区.在温度较高的时段,城市地区的NH_(3)浓度与农村地区的浓度水平相当,表明非农业源排放对城市地区NH_(3)浓度的贡献是不可忽视的.在对先验廓线进行分类时,CrIS卫星的快速物理检索算法(CrIS Fast Physical Retrieval algorithm,简称CFPR)对我国不同区域NH_(3)的实际浓度水平有所低估.因此,提高CrIS卫星反演NH_(3)浓度的能力可考虑对先验廓线进行重新分类.展开更多
Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfil...Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this purpose.In this study,the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS)full spectrum resolution is used to select and pair channels from longwave(~15μm)and shortwave(~4.3μm)CO2 absorption bands under stricter conditions,so as to better detect ice clouds.Besides,the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be minimized.The training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS)cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO2 absorption channels.From the linear relationship,the so-called cloud emission and scattering index(CESI)is derived to detect ice clouds.CESI clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h Pa.Moreover,the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers.展开更多
CRIS的全称是近期科研情报系统(Current Research Information System)。这是个进展中的农业研究情报存贮与检索系统,是了解美国当前农业科研进展情况的情报数据库。1988年我馆引进了这个数据库的光盘检索系统后,在校内开展了检索服务,...CRIS的全称是近期科研情报系统(Current Research Information System)。这是个进展中的农业研究情报存贮与检索系统,是了解美国当前农业科研进展情况的情报数据库。1988年我馆引进了这个数据库的光盘检索系统后,在校内开展了检索服务,受到广大师生普遍欢迎。大家一致认为这个系统提供的科研情报新、信息量大。展开更多
The world in 2019 was generally peaceful and stable.For major countries,despite more confrontations and frictions among them,there was also contact through competition as well as selective cooperation,and the bottom l...The world in 2019 was generally peaceful and stable.For major countries,despite more confrontations and frictions among them,there was also contact through competition as well as selective cooperation,and the bottom line of no military conflict or war was not crossed.Nevertheless,the global security in 2019 was also marked by chaos and crisis.There were more sources of upheavals and risks,the regional security situations were more complex and severe,and progress of global security governance was obstructed by difficulties.Political and social turmoils in some countries were threatening to spill over to the whole region,even to the whole world.展开更多
文摘大气温湿廓线是数值预报中最基本的气象参数，高光谱红外卫星可以观测到较高垂直分辨率的大气信息，为了准确获取廓线信息，利用搭载于美国对地观测卫星Suomi NPP（national polar-orbiting partner-ship）平台上的CrIS（cross-track infrared sounder）红外高光谱观测资料，讨论了通道选取方法，采用特征向量统计法反演法得到初始大气廓线，利用非线性牛顿迭代法进一步提高反演精度。将反演结果和全球数据同化系统GDAS（global data assimilation system ）模式分析数据以及配对的无线探空值进行比较，发现反演结果与真值趋势一致，较之初始廓线有显著提高，在100～700 hPa之间，温度廓线反演精度最高，均方差小于1 K ，在300～900 hPa之间，湿度廓线反演精度最高，均方差小于20％，与所选取通道的雅各比峰值区间一致。
文摘基于地面观测与CrIS卫星反演的数据,分析了我国2015年9月—2016年8月的大气氨(NH_(3))浓度在时空上的变化特征,并评估了这两类数据之间存在的差异.结果表明:基于CrIS卫星反演的数据能够很好地识别我国NH_(3)浓度在时空上的变化趋势,但同地面观测相比,存在数值上的低估.我国的NH_(3)浓度总体上呈现出“夏高冬低”的特点.就空间分布而言,华北、华东和中南地区是我国目前NH_(3)浓度相对较高的地区.在温度较高的时段,城市地区的NH_(3)浓度与农村地区的浓度水平相当,表明非农业源排放对城市地区NH_(3)浓度的贡献是不可忽视的.在对先验廓线进行分类时,CrIS卫星的快速物理检索算法(CrIS Fast Physical Retrieval algorithm,简称CFPR)对我国不同区域NH_(3)的实际浓度水平有所低估.因此,提高CrIS卫星反演NH_(3)浓度的能力可考虑对先验廓线进行重新分类.
基金National Key R&D Program(2018YFC1506904)Natural Science Foundation of China(41590873,41705089)。
文摘Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this purpose.In this study,the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS)full spectrum resolution is used to select and pair channels from longwave(~15μm)and shortwave(~4.3μm)CO2 absorption bands under stricter conditions,so as to better detect ice clouds.Besides,the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be minimized.The training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS)cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO2 absorption channels.From the linear relationship,the so-called cloud emission and scattering index(CESI)is derived to detect ice clouds.CESI clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h Pa.Moreover,the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers.
文摘CRIS的全称是近期科研情报系统(Current Research Information System)。这是个进展中的农业研究情报存贮与检索系统,是了解美国当前农业科研进展情况的情报数据库。1988年我馆引进了这个数据库的光盘检索系统后,在校内开展了检索服务,受到广大师生普遍欢迎。大家一致认为这个系统提供的科研情报新、信息量大。
文摘The world in 2019 was generally peaceful and stable.For major countries,despite more confrontations and frictions among them,there was also contact through competition as well as selective cooperation,and the bottom line of no military conflict or war was not crossed.Nevertheless,the global security in 2019 was also marked by chaos and crisis.There were more sources of upheavals and risks,the regional security situations were more complex and severe,and progress of global security governance was obstructed by difficulties.Political and social turmoils in some countries were threatening to spill over to the whole region,even to the whole world.
