Comparative Evaluation Of Ice Cloud Properties Of Different Passive Sensors In China

The horizontal distribution of ice clouds affects the Earth-atmosphere radiation system,causing differences in radiation balance,an important factor in radiative forcing,and a major source of understanding of climate uncertainty.In order to evaluate the differences and causes of ice cloud data of different passive polar orbiting satelite sensors,find out the products that are closer to the actual characteristics of ice clouds,and improve the utilization of satellite data in the cloud area,this paper selects the L3 of MODIS,AIRS,AIRS/AMSU-A from January 2013 to December 2015,referencing to the DARDAR L2 products,taking the overall horizontal migration of the ice cloud characteristics,the numerical value of the small scale range and the annual change and seasonality of the three-year period in China as a research condition.According to the thermodynamic phase and satellite data,the ice clouds occurrence frequency,ice clouds optical thickness,ice clouds effective particle radius and ice clouds top temperature were calculated,and the differences of four data ice cloud characteristics under different research conditions are compared and analyzed.And draws the following conclusions:The research results of the ice cloud occurrence frequency of the four data are consistent with the increase of China land with the increase of latitude,the sea decreases with the increase of latitude,and there is a high value area on the eastern slope of the Qinghai-Tibet Plateau.It is more reasonable to select MODIS to describe the overall change in China;In all small terrestrial areas of China land,the numerical values of AIRS/AMSU-A are closer to DARDAR data,MODIS can be used to describe the ice clouds occurrence frequency in eastern sea,while the southern sea is AIRS/AMSU-A;Whether in the land or sea,three-year changes and seasonal laws of ice clouds occurrence frequency should choose MODIS passive sensors.The ice clouds optical thickness in China by DARDAR data is between 2-8,AIRS and AIRS/AMSU-A are in 4-6,MODIS is mostly within 6-16,a little even reached 20.Four data in China land are characterized by large south and small north,and the sea is slightly larger than land.It is suitable to select AIRS/AMSU-A data to describe the overall horizontal distribution of ice clouds optical thickness;In China land and eastern sea,AIRS/AMSU-A with microwaves is closer to DARDAR data with the numerical value,while the southern sea is better for MODIS;Whether land or sea in China,the annual variation extent of AIRS and AIRS/AMSU-A are too small so that can only fluctuate between 3-5,MODIS is closer to active products.With AIRS,AIRS/AMSU-A and DARDAR data,the variation of ice particle radius in southern land is higher and lower in north.The opposite of MODIS is smaller in southwest land and larger in northeast.And the sea is slightly smaler than land,particularly in the southern sea.AIRS should be selected to analyze the overall distribution of the ice clouds effective particle radius in China;However,in the study of the numerical magnitude in all smal-scale areas,MODIS passive sensor is closer to active products;The annual variation of ice radius is still closest to active product with MODIS,and AIRS/AMSU-A which integrates microwave in China land,can improve the annual change and seasonality law than signal infrared research.From the southern sea to the northern land,the ice clouds top temperature of the DARDAR first increases and then decreases.In the southern sea is about 210 K,the southwest,the south,and the middle China are up to 245 K,and the north land is smaler about 235 K.it is more appropriate to select the AIRS for the overall ice clouds top temperature change in China;The numerical study in different small scale regions is suitable for the selection of passive sensors: AIRS is suitable for the northwest,Qinghai-Tibet Plateau,southern land and southern sea,while in north,southwest land and eastern sea MODIS is closer to DARDAR data;MODIS is suitable for studying the years' change and analyzing the overall time trend in China,and seasonal features is better for AIRS passive sensors.