Ultraviolet Radiation evolution during the 21st century

Abstract : In the context of a changing climate, the acceleration of the Brewer-Dobson circulation [Butchart 2014] leads to a decrease of the ozone total column in the tropics. This decrease affects directly surface ultraviolet radiation, which are already very high in this area. Following the work of (Bais et al., 2011), (Butchart, 2014) and (Hegglin & Shepherd, 2009) on the future evolution of surface irradiance derived from Chemistry Climate Models (CCM) projections, we projected here surface irradiance from 2010 to 2100 with focus on the tropics. We used the latest chemistry climate projection exercise ; Chemistry Climate Model Initiative (CCMI) coupled with a radiative transfer model (TUV (Madronich, 1993)) to calculate the evolution of surface Ultraviolet radiation throughout the 21st century. Ultraviolet Index (UVi) has been specifically considered (McKenzie, Matthews, & Johnston, 1991). At first, simulation from RefC2 Chemistry Climate Model Initiative have been coupled with a radiative transfer model, in order to obtained modeled UV index (UVi-M). UVi-M is then compared against available satellite ultraviolet radiation observations (OMI OMUVbd product) between 2005 and 2016. Statistical difference and variance have been analysed versus different parameters: geographical location, model or ensemble of model outputs used in the radiative transfer calculation.