Sensitivity of mesoscale modeling of smoke direct radiative effect to the emission inventory: A case study in northern sub-Saharan African region

Authors:

Feng Zhang^1,2, Jun Wang¹, Charles Ichoku³, Edward J. Hyer³, Zhifeng Yang¹, Cui Ge^1,6, Shenjian Su⁵, Xiaoyang Zhang⁷, ShobhaKondragunta⁸, Johannes W. Kaiser^9,10,11, Christine Wiedinmyer ¹², Arlindo da Silva³

¹ Department of Earth and Atmospheric Sciences, University of Nebraska – Lincoln, Lincoln, NE, USA

² International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029

³ NASA Goddard Space Flight Center, Greenbelt, Maryland, USA

⁴ Naval Research Lab- Monterey, CA, USA.

⁵ Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA

⁶ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

⁷ Geospatial Science Center of Excellence (GSCE), South Dakota State University, SD, USA.

⁸ NOAA/NESDIS Center for Satellite Applications, Research College Park, MD, USA.

⁹ King’s College London, London WC2R 2LS, United Kingdom

¹⁰ European Centre for Medium-range Weather Forecasts, Reading RG2 9AX, United Kingdom

¹¹ Max Planck Institute for Chemistry, 55128 Mainz, Germany

¹² Atmospheric Chemistry Division, NCAR Earth System Laboratory, National Center for Atmospheric Research, Boulder, CO 80301, USA

Abstract:

An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of 7 or less are found in the simulated regional (15°W–42°E, 13°S–17°N) and monthly averages of column PM2.5loading, surface PM2.5concentration, aerosol optical depth (AOD), smoke radiative forcing at the top-of-atmosphere and at the surface, and air temperature at 2 m and at 700 hPa. The smaller differences in these simulated variables may reflect the atmospheric diffusion and deposition effects to dampen the large difference in smoke emissions that are highly concentrated in areas much smaller than the regional domain of the study. Indeed, at the local scale, large differences (up to a factor of 33) persist in simulated smoke-related variables and radiative effects including semi-direct effect. Similar results are also found for November 2010, despite differences in meteorology andfire activity. Hence, biomass burning emission uncertainties have a large influence on the reliability of model simulations of atmospheric aerosol loading, transport, and radiative impacts, and this influence is largest at local and hourly-to-daily scales. Accurate quantification of smoke effects on regional climate and air quality requires further reduction of emission uncertainties, particularly for regions of highfire concentrations such as NSSA.

Key words:

fire emission inventory, Sahel and northern sub-Saharan African region, smoke radiative effect, mesoscale modeling, air quality

Citation:

Feng Zhang, Jun Wang, Charles Ichoku, Edward J. Hyer, Zhifeng Yang, Cui Ge, Shenjian Su, Xiaoyang Zhang, ShobhaKondragunta, Johannes W. Kaiser, Christine Wiedinmyer , Arlindo da Silva

2014 Environ. Res. Lett. 9 075002 (http://iopscience.iop.org/1748-9326/9/7/075002)