天气变化下预测PM2.5.pptx

Forecasting fine particulate matter (PM2.5) across the United States in a changing climate;2;Surface ozone and particulate matter are harmful to human health.;4;5;6;Coming climate change will likely affect PM2.5 concentrations. Models disagree on the sign and the magnitude of the impacts ; Hayman fire, June 8-22, 2002 56,000 ha burned 30 miles from Denver and Colorado Springs ;Gillett et al., 2004;First, a few slides on chemistry + climate models.;11;Simulations of future climate depend on the path of socio-economic development.;IPCC AR4 models show increasing temperatures across North America by 2100 in A1B scenario.;14;Two constellations of studies Sensitivity of PM2.5 to changing meteorology in the East. Sensitivity of wildfires to changing climate in the West and the consequences for PM2.5. ;Surface ozone levels are sensitive to cold-front passage.;Multiple linear regression coefficients for total PM2.5 on meteorological variables. Units: μg m-3 D-1 (p-value 0.05);We used Principal Component Analysis to define the main meteorological modes driving PM2.5 variability over the US. Models show increased duration of stagnation in the East, with corresponding increases in annual mean PM2.5. This approach could provide a useful tool to assess climate penalty on PM2.5. We use observed relationships + climate models, no chemistry models. ;How do we predict fires in a future climate?We don’t have a good mechanistic approach for modeling wildfires. ;Predictions of area burned are made for large eco-regions for the fire season;Regression matches observed area burned, except for California coastal shrub;;Effect of future fires in a future climate on organic carbon in the western U.S.;Results shown so far were driven by one climate model. But models show large variation in response to changing greenhouse gases.;Wildfires in western US are predicted to increase by ~60% by 2050s.;Median GCM results show an increase in area burned in all regions.;Yue et al., ms.;