IMPACTS OF PROJECTED CLIMATE SCENARIOS ON FUTURE AIR QUALITY AND WATER-CARBON CYCLE IN THE UNITED STATES
Y. ZHANG, K. WANG, C. JENA, K. DUAN, G. SUN, S. MCNULTY, F. YAN, Z.-F. LU, D. STREETS
ABSTRACT. – Impacts of projected climate scenarios on future air quality and water-carbon cycle in the United States. Projected changes in anthropogenic emissions and climate changes will impact future air quality, water and carbon cycles, as well as human and environmental health in the United States. In this work, we applied an advanced online-coupled meteorology and chemistry model and an ecohydrological model to simulate such impacts on future air quality, water supplies, and carbon cycles over the continental U.S. for current (2001-2010) and future (2046-2055) years under four climate and emission scenarios including the Representative Concentration Pathways (RCP) 4.5 and 8.5 and the Technology Driver Model (TDM) 1B and B2. A comprehensive evaluation of atmospheric predictions for the current decade using available observations shows an overall good model performance. Future air quality features greater reduction in PM2.5 by RCP 4.5/8.5 than TDM B2/A1B and decreased ozone (O3) over most areas by RCP4.5 and TDM B2, indicating the benefits of carbon policy and technology improvements with greater emission reductions. The climate warming and reduction in precipitation induced by air pollution are projected to lead to a reduction in water yield under both RCP scenarios but an increase in gross ecosystem productivity in some areas under the RCP8.5 scenario. The results show that air pollution is an important factor to be considered in projecting the impacts of climate change on water and carbon cycles at the continental scale.
Keywords: air quality modeling, water-carbon cycle modeling, climate and emission scenarios, WRF/Chem, WaSSI.