TY - JOUR TI - Local ecological knowledge and incremental adaptation to changing flood patterns in the Amazon delta T2 - Sustainability Science DA - 2016/7// PY - 2016/7// DO - 10.1007/s11625-015-0352-2 UR - http://dx.doi.org/10.1007/s11625-015-0352-2 ER - TY - JOUR TI - Evaluation of a High-Resolution SPI for Monitoring Local Drought Severity AU - Cumbie-Ward, Rebecca V. AU - Boyles, Ryan P. T2 - Journal of Applied Meteorology and Climatology AB - Abstract A standardized precipitation index (SPI) that uses high-resolution, daily estimates of precipitation from the National Weather Service over the contiguous United States has been developed and is referred to as HRD SPI. There are two different historical distributions computed in the HRD SPI dataset, each with a different combination of normals period (1971–2000 or 1981–2010) and clustering solution of gauge stations. For each historical distribution, the SPI is computed using the NCEP Stage IV and Advanced Hydrologic Prediction Service (AHPS) gridded precipitation datasets for a total of four different HRD SPI products. HRD SPIs are found to correlate strongly with independently produced SPIs over the 10-yr period from 2005 to 2015. The drought-monitoring utility of the HRD SPIs is assessed with case studies of drought in the central and southern United States during 2012 and over the Carolinas during 2007–08. A monthly comparison between HRD SPIs and independently produced SPIs reveals generally strong agreement during both events but weak agreement in areas where radar coverage is poor. For both study regions, HRD SPI is compared with the U.S. Drought Monitor (USDM) to assess the best combination of precipitation input, normals period, and station clustering solution. SPI generated with AHPS precipitation and the 1981–2010 PRISM normals and associated cluster solution is found to best capture the spatial extent and severity of drought conditions indicated by the USDM. This SPI is also able to resolve local variations in drought conditions that are not shown by either the USDM or comparison SPI datasets. DA - 2016/10// PY - 2016/10// DO - 10.1175/jamc-d-16-0106.1 VL - 55 IS - 10 SP - 2247-2262 UR - http://dx.doi.org/10.1175/jamc-d-16-0106.1 ER - TY - JOUR TI - The Impact of Incongruous Lake Temperatures on Regional Climate Extremes Downscaled from the CMIP5 Archive Using the WRF Model T2 - Journal of Climate AB - Abstract The impact of incongruous lake temperatures is demonstrated using the Weather Research and Forecasting (WRF) Model to downscale global climate fields. Unrealistic lake temperatures prescribed by the default WRF configuration cause obvious biases near the lakes and also affect predicted extremes hundreds of kilometers from the lakes, especially during winter. Using these default temperatures for the Great Lakes in winter creates a thermally induced wave in the modeled monthly average sea level pressure field, which reaches southern Florida. Differences of more than 0.5 K in monthly average daily maximum 2-m temperature occur along that wave during winter. Noteworthy changes to temperature variability, precipitation, and mesoscale circulation also occur when the default method is used for downscaling. Consequently, improperly setting lake temperatures for downscaling could result in misinterpreting changes in regional climate and adversely affect applications reliant on downscaled data, even in areas remote from the lakes. DA - 2016/1// PY - 2016/1// DO - 10.1175/jcli-d-15-0233.1 UR - http://dx.doi.org/10.1175/jcli-d-15-0233.1 KW - Circulation KW - Dynamics KW - Lake effects KW - Stationary waves KW - Physical Meteorology and Climatology KW - Mass fluxes KW - transport KW - Models and modeling KW - Climate models KW - Mesoscale models KW - Regional models ER - TY - JOUR TI - The Sensitivity of WRF Downscaled Precipitation in Puerto Rico to Cumulus Parameterization and Interior Grid Nudging T2 - Journal of Applied Meteorology and Climatology AB - Abstract The sensitivity of the precipitation over Puerto Rico that is simulated by the Weather Research and Forecasting (WRF) Model is evaluated using multiple combinations of cumulus parameterization (CP) schemes and interior grid nudging. The NCEP–DOE AMIP-II reanalysis (R-2) is downscaled to 2-km horizontal grid spacing both with convective-permitting simulations (CP active only in the middle and outer domains) and with CP schemes active in all domains. The results generally show lower simulated precipitation amounts than are observed, regardless of WRF configuration, but activating the CP schemes in the inner domain improves the annual cycle, intensity, and placement of rainfall relative to the convective-permitting simulations. Furthermore, the use of interior-grid-nudging techniques in the outer domains improves the placement and intensity of rainfall in the inner domain. Incorporating a CP scheme at convective-permitting scales (<4 km) and grid nudging at non-convective-permitting scales (>4 km) improves the island average correlation of precipitation by 0.05–0.2 and reduces the island average RMSE by up to 40 mm on average over relying on the explicit microphysics at convective-permitting scales with grid nudging. Projected changes in summer precipitation between 2040–42 and 1985–87 using WRF to downscale CCSM4 range from a 2.6-mm average increase to an 81.9-mm average decrease, depending on the choice of CP scheme. The differences are only associated with differences between WRF configurations, which indicates the importance of CP scheme for projected precipitation change as well as historical accuracy. DA - 2016/10// PY - 2016/10// DO - 10.1175/jamc-d-16-0121.1 UR - http://dx.doi.org/10.1175/jamc-d-16-0121.1 ER - TY - JOUR TI - Co-benefits of global and regional greenhouse gas mitigation for US air quality in 2050 T2 - Atmospheric Chemistry and Physics AB - Policies to mitigate greenhouse gas (GHG) emissions will not only slow climate change, but can also have ancillary benefits of improved air quality. Here we examine the co-benefits of both global and regional GHG mitigation on U.S. air quality in 2050 at fine resolution, using dynamical downscaling methods, building on a previous global co-benefits study (West et al., 2013). The co-benefits for U.S. air quality are quantified via two mechanisms: through reductions in co-emitted air pollutants from the same sources, and by slowing climate change and its influence on air quality, following West et al. (2013). Additionally, we separate the total co-benefits into contributions from domestic GHG mitigation versus mitigation in foreign countries. We use the WRF model to dynamically downscale future global climate to the regional scale, the SMOKE program to directly process global anthropogenic emissions into the regional domain, and we provide dynamical boundary conditions from global simulations to the regional CMAQ model. The total co-benefits of global GHG mitigation from the RCP4.5 scenario compared with its reference are estimated to be higher in the eastern U.S. (ranging from 0.6-1.0 μg m-3) than the west (0-0.4 μg m-3) for PM2.5, with an average of 0.47 μg m-3 over U.S.; for O3, the total co-benefits are more uniform at 2-5 ppb with U.S. average of 3.55 ppb. Comparing the two mechanisms of co-benefits, we find that reductions of co-emitted air pollutants have a much greater influence on both PM2.5 (96% of the total co-benefits) and O3 (89% of the total) than the second co-benefits mechanism via slowing climate change, consistent with West et al. (2013). GHG mitigation from foreign countries contributes more to the U.S. O3 reduction (76% of the total) than that from domestic GHG mitigation only (24%), highlighting the importance of global methane reductions and the intercontinental transport of air pollutants. For PM2.5, the benefits of domestic GHG control are greater (74% of total). Since foreign contributions to co-benefits can be substantial, with foreign O3 benefits much larger than those from domestic reductions, previous studies that focus on local or regional co-benefits may greatly underestimate the total co-benefits of global GHG reductions. We conclude that the U.S. can gain significantly greater domestic air quality co-benefits by engaging with other nations to control GHGs. DA - 2016/8/1/ PY - 2016/8/1/ DO - 10.5194/acp-16-9533-2016 UR - http://dx.doi.org/10.5194/acp-16-9533-2016 ER - TY - JOUR TI - Interaction Between Two Distinct Mesoscale Circulations During Summer in the Coastal Region of Eastern USA AU - Sims, Aaron P. AU - Raman, Sethu T2 - BOUNDARY-LAYER METEOROLOGY DA - 2016/7// PY - 2016/7// DO - 10.1007/s10546-015-0125-6 VL - 160 IS - 1 SP - 113-132 SN - 1573-1472 KW - Circulations KW - Coastal Carolinas KW - Convection KW - Sandhills KW - Sea breeze ER - TY - JOUR TI - Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios AU - Glotfelty, Timothy AU - Zhang, Yang AU - Karamchandani, Prakash AU - Streets, David G. T2 - ATMOSPHERIC ENVIRONMENT AB - The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m−3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere’s near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth’s surface with a global average reduction in shortwave radiation of 1.2 W m−2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR’s CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed treatments. This study indicates that effective climate mitigation and emission control strategies are needed to prevent future health impact and ecosystem stress. Further, studies that are used to develop these strategies should use fully coupled models with sophisticated chemical and aerosol-interaction treatments that can provide a more realistic representation of the atmosphere. DA - 2016/8// PY - 2016/8// DO - 10.1016/j.atmosenv.2016.05.008 VL - 139 SP - 176-191 SN - 1873-2844 KW - Global climate and emissions change KW - Future air quality KW - Aerosol direct effect KW - Aerosol indirect effects KW - Online-coupled model KW - GU_WRF/Chem ER - TY - JOUR TI - Divergence of ecosystem services in US National Forests and Grasslands under a changing climate AU - Duan, Kai AU - Sun, Ge AU - Sun, Shanlei AU - Caldwell, Peter V. AU - Cohen, Erika C. AU - McNulty, Steven G. AU - Aldridge, Heather D. AU - Zhang, Yang T2 - SCIENTIFIC REPORTS AB - The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m(-2) yr(-1) (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr(-1) (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr(-1)). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services. DA - 2016/4/21/ PY - 2016/4/21/ DO - 10.1038/srep24441 VL - 6 SP - SN - 2045-2322 ER - TY - JOUR TI - Decadal evaluation of regional climate, air quality, and their interactions over the continental US and their interactions using WRF/Chem version 3.6.1 AU - Yahya, K. AU - Wang, K. AU - Campbell, P. AU - Glotfelty, T. AU - He, J. AU - Zhang, Y. T2 - Geoscientific Model Development DA - 2016/// PY - 2016/// VL - 9 IS - 2 SP - 671-695 ER -