GNSS occultation sounding for climate monitoring

Considerable efforts are currently invested into the setup of a Global Clim ate Observing System (GCOS) for monitoring climate change over the coming d ecades, which is of high relevance given concerns on increasing human influ ences. A promising potential contribution to the GCOS is a suite of spacebo rne Global Navigation Satellite System (GNSS) occultation sensors for globa l long-term monitoring of atmospheric change in temperature and other varia bles with high vertical resolution and accuracy. Besides the great importan ce with respect to climate change, the provision of high quality data is es sential for the improvement of numerical weather prediction and for reanaly sis efforts. We review the significance of GNSS radio occultation sounding in the climate observations context. In order to investigate the climate change detection capability of GNSS occ ultation sensors, we are currently performing an end-to-end GNSS occultatio n observing system simulation experiment over the 25-year period 2001 to 20 25. We report on this integrated analysis, which involves in a realistic ma nner all aspects from modeling the atmosphere via generating a significant set of simulated measurements to an objective statistical analysis and asse ssment of 2001-2025 temporal trends. (C) 2001 Elsevier Science Ltd. All rig hts reserved.