Observing upper troposphere–lower stratosphere climate with radio occultation data from the CHAMP satellite

摘要: High quality observations of the atmosphere are particularly required for monitoring global climate change. Radio occultation (RO) data, using Global Navigation Satellite System (GNSS) signals, well suited this challenge. The special utility RO data arises from their long-term stability due to self-calibrated nature. German research satellite CHAllenging Minisatellite Payload geoscientific (CHAMP) continuously records profiles since August 2001 providing first opportunity create based climatologies a multi-year period more than 5 years. A missing CHAMP July 3, 2006 8, can be bridged with GRACE (Gravity Recovery and Climate Experiment). We have built seasonal zonal mean atmospheric (dry) temperature, microwave refractivity, geopotential height pressure 10° latitudinal resolution. show representative results focus on dry temperatures compare them analysis European Centre Medium-Range Weather Forecasts (ECMWF). Although we available only about 150 per day (compared millions entering ECMWF analyses) overall agreement between 8 30 km altitude is in general very good systematic differences <0.5 K most parts domain. Pronounced (exceeding 2 K) tropical tropopause region above Antarctica southern winter almost entirely attributed errors analyses. Errors resulting uneven sampling space time potential error source single-satellite climatologies. average means <0.2 K, higher values occur restricted regions intervals which clearly identified by estimation approach introduced (which fields). total new type temperature estimated below km. recently launched Taiwan/U.S. FORMOSAT-3/COSMIC constellation 6 satellites started provide thousands day, but already now improve upon modern operational upper troposphere–lower stratosphere act as absolute reference validation bias-sensitive datasets models.