CM SAF TOA Radiation GERB/SEVIRI Data Record - Edition 2

The TOA Radiation GERB/SEVIRI record from CM SAF provides estimates of the Top Of Atmosphere broadband radiative fluxes derived
from the Geostationary Earth Radiation Budget (GERB) and the Spinning Enhance Visible and InfraRed Imager (SEVIRI)
sensors onboard the Meteosat Second Generation satellites.
The outgoing radiation is reported in terms of TOA Reflected Solar (TRS) and TOA Emitted Thermal (TET) fluxes.
This second edition is the improved and extended follow-up of the first edition of the record available from CM SAF under DOI 10.5676/EUM_SAF_CM/TOA_GERB/V001.
The main improvements are:
(1) In addition to the all sky fluxes, the edition 2.0 also provides an estimate of the corresponding clear sky fluxes.
(2) A correction is applied for the GERB and SEVIRI sensor ageing.
(3) Data from the MSG1, MSG2 and MSG3 satellites have been homogenized.
(4) Data from the backup MSG satellite has been used to reduce the gaps in the data record.
(5) The temporal coverage is extended to 1st Feb. 2004 - 30th April 2015.

The original GERB level 2.0 High Resolution (HR) and SEVIRI level 1.5 observations have been processed to estimate solar and thermal fluxes
in hourly boxes on the GERB HR grid.
From the hourly values, the daily mean, the monthly mean and the monthly mean diurnal cycle are estimated.
Finally, the data is regridded on a regular latitude-longitude grid covering 70°N - 70° and 70°W-70°E, with a spatial resolution of 0.1°.
Being based on 15' geostationary observations, the data record is very well suited to study the diurnal cycle of atmospheric radiation, e.g. the effect of convection on the OLR.
The spatial resolution of the data, 0.1°, allows to study the effect on the radiation budget of processes taking place at fine spatial scale, e.g. valley fog.
Combining the all-sky and clear-sky allows quantifying the cloud radiative effects at high spatial and temporal resolution.

CM SAF发布的TOA辐射GERB/SEVIRI数据集，提供了基于静止地球辐射收支（Geostationary Earth Radiation Budget, GERB）与自旋增强型可见红外成像仪（Spinning Enhanced Visible and InfraRed Imager, SEVIRI）传感器反演得到的大气层顶宽带辐射通量估算结果，上述传感器搭载于Meteosat第二代（Meteosat Second Generation, MSG）卫星之上。
该数据集向外辐射通量分为大气层顶反射太阳辐射（TOA Reflected Solar, TRS）与大气层顶发射热辐射（TOA Emitted Thermal, TET）两类。
本第二版数据集是CM SAF此前发布的第一版数据集（DOI: 10.5676/EUM_SAF_CM/TOA_GERB/V001）的改进与扩展后继版本，其主要改进如下：
1. 除全天空辐射通量外，2.0版还新增了对应晴空条件下的辐射通量估算结果；
2. 针对GERB与SEVIRI传感器的老化效应完成了校正处理；
3. 对MSG1、MSG2及MSG3三颗卫星的观测数据进行了均一化校准；
4. 引入备份MSG卫星的观测数据，以填补原数据集的时间间隙；
5. 时间覆盖范围扩展至2004年2月1日至2015年4月30日。

研究团队以GERB高分辨率（High Resolution, HR）网格为基础，在小时级窗口内，基于原始GERB 2.0级高分辨率观测数据与SEVIRI 1.5级观测数据反演得到太阳与热辐射通量。基于逐小时通量数据，进一步计算得到日平均、月平均及月平均日循环周期通量。最终，所有数据被重采样至覆盖70°N~70°S、70°W~70°E的常规经纬网格，空间分辨率为0.1°。
由于该数据集基于15分钟间隔的静止卫星观测，十分适用于大气辐射日循环特征的相关研究，例如对流对长波辐射（Outgoing Longwave Radiation, OLR）的影响效应。其0.1°的空间分辨率则可支撑小尺度过程（如山谷雾）对辐射收支影响的相关研究。结合全天空与晴空通量数据，可实现高时空分辨率下云辐射效应的定量分析。