Climate Change Detection And Attribution Using GPS Radio Occultation And CMIP5 GCM Data

General circulation models (GCMs) show a distinct anthropogenic fingerprint - the thermal expansion of Hadley Cell. This response to the increase of atmospheric concentration of greenhouse gases (GHG) is evident under a variety of forcing scenarios. However the investigation of the anthropogenic signal in the real climate system is challenging because anthropogenic signal is immersed in the natural variability and it requires highly quality data to separate signal from background variability. GPS Radio Occultation (GPS RO) technique becomes close to meeting all of the quality requirements, enabling it to become the benchmark for the climate data. The analysis was implemented for upper troposphere - lower stratosphere (UTLS) region between 50°N and -50°S latitudes. Vertical profiles of temperature and geopotential heights from 2001-2006 CHAMP and 2006-2011 COSMIC missions and CMIP5 GCM data for the same variables and time period were used in this study. Whether the anthropogenic signal is distinguishable from natural variability of the climate is being investigated using optimal fingerprinting technique. Temperature trend patterns allow the detection of climate change on 90% significance level but not the attribution, while the geoptential height trend patterns show that the detection of anthropogenic climate influence is achieved on more than 99% significance level.