摘要
利用红外高光谱探测仪(Infrared Atmospheric Sounding Interferometer,IASI)在二氧化碳吸收带的长短波红外通道对云反应程度的不同来探测云。依据不同通道的权重函数峰值高度和云不敏感层高度将IASI长短波红外通道进行配对,成功配对的长短波红外通道晴空亮温之间建立线性回归模型,即通过长波红外通道亮温可以线性回归得到配对的短波通道亮温,将短波通道的晴空回归亮温和观测亮温之差定义为云指数。权重函数峰值高度位于383 hPa的云指数空间分布和云成分为冰的空间分布较为一致,尤其在赤道和低纬度地区。权重函数峰值高度位于790 hPa的云指数空间分布和低云云顶气压也有较好的一致性。
The Infrared Atmospheric Sounding Interferometer(IASI)is applied to perform cloud detection,by using the different responses to clouds between longwave and shortwave channels at CO 2 bands.First,IASI longwave channels are paired with shortwave channels based on weighing function altitudes and sensitivity to clouds.A linear relationship of the brightness temperatures between each pair of channels is then established to predict the shortwave channel from the longwave channel under clear sky conditions.Finally,a cloud emission and scattering index(CESI)can be defined as the difference in the paired shortwave channel between the regression model predicted and the observed brightness temperatures.The spatial distribution of the CESIs with weighting functions peaking at around 383 hPa is consistent with that of the cloud phase of ice,especially at the equator and low latitudes.The spatial distribution of CESIs with weighting functions peaking at around 790 hPa agrees well with the distribution of the low cloud top pressure.
作者
李琪
邹晓蕾
LI Qi;ZOU Xiaolei(Emergency Information Warning Center of Guangdong Province/Weather-Modification Center of Guangdong Province,Guangzhou 510640,China;Earth System Science Interdisciplinary Center,University of Maryland,College Park,MD 20742,USA)
出处
《大气科学学报》
CSCD
北大核心
2020年第5期856-866,共11页
Transactions of Atmospheric Sciences
基金
国家重点研发计划项目(2018YFC1506702)。
关键词
红外高光谱探测仪
长短波红外通道
权重函数
云不敏感层
云指数
infrared atmospheric sounding interferometer
longwave and shortwave infrared channels
weighting function
cloud-insensitive level
cloud emission and scattering index
