EUMETSAT's Contribution to the Generation of High-Quality Climate Data Records
The detection of climate change and analysis of climate variability at inter-annual scales requires well calibrated observations and long-term homogeneity of time series of data. These time series can be utilised in direct analysis of the climate system but also within Numerical Weather Prediction (NWP) models to create a physically consistent reanalysis. EUMETSAT participates in the EU FP-7 project European Re-Analysis of global CLIMate observations (ERA-CLIM). This project has the major task to prepare all kinds of observations for a next major century long reanalysis. Within ERA-CLIM EUMETSAT is regenerating radiance data and a couple of geophysical products for almost all its instruments in geostationary and polar orbit. Particularly, the reprocessing of the radiance data has the goal to establish data records suitable for reanalysis and climate analysis. Instrument records are carefully analysed and where possible corrected for a number of deficiencies. The inter-calibration of instruments following the principles and methodologies of the international Global Space Based Inter-calibration System (GSICS) activity might alleviate the assimilation process by leading to a more homogeneous bias correction per instrument class in the NWP systems. This presentation gives an overview of EUMETSAT's activities to generate high-quality Climate Data Records. Examples of products such as reprocessed GOME-2 Level 1 data, ASCAT backscatter data and polar Atmospheric Motion Vectors derived from Metop-A AVHRR will be shown. Individual challenges such as the inter-satellite calibration of geostationary and polar orbiting data and the evaluation of CDR quality will be discussed in more detail. The first will give examples from studying the temporal stability of HIRS and Meteosat observations when compared to IASI and the latter will show summary results from an independent validation of the Meteosat First Generation surface albedo record.