RESEARCH STATEMENT 1. OVERVIEW My research group studies the impacts of atmospheric aerosols on air quality, weather, and climate. My research approaches include satellite remote sensing, meteorology-chemistry coupled numerical modeling, data assimilation, statistical analysis, and integration of these elements. Aerosols, such as wind-blown dust particles and those particulate matters emitted from power plants, car engines, industrial manufactories, volcanic eruptions, and wildfires, degrade the air quality and visibility. They also affect climate by reflecting sunlight, and by their microphysical impact on cloud formation and precipitation. Quantifying aerosol radiative effects are important for prediction of surface temperature, solar input to the biosphere (such as photosynthesis of crops), photochemical processes, and climate changes at both regional and global scales. In addition, aerosols play an important role in atmospheric heterogeneous chemistry and serve as a carrier to supply nutrients (such as dust) to the biosphere (such as forests). Quantifying the role of aerosols in the Earth system is a challenging task, because atmospheric aerosols have much shorter lifetimes (hours to days) and much larger spatiotemporal variations than greenhouse gases (such as well-mixed CO2 with a lifetime of hundred years in the atmosphere). Indeed, the latest report by the Intergovernmental Panel on Climate Change (IPCC, 2007) identifies the aerosol effect on climate as the source for the largest uncertainties in the climate models. The aerosol microphysical variability in space and time as well as its connections to the air quality and climate system is the central theme of my research at UNL. What makes my research unique is that I combine both satellite/ground remote sensing and meteorology-chemistry coupled models to understand the aerosol processes from emission and atmospheric transport to aerosol chemistry and the interaction of aerosols with sunlight and clouds. Quantitative description of aerosols from space (such as the NASA’ Earth Observation System) only began in the early 21st century. Therefore, my proposed research program addresses a recognized national priority that is likely to increase in importance in the future. This conjecture is supported by my research outcomes in the last 5 years at UNL. Through competition to win proposals and collaborations with researchers in NASA, Navy, and other universities, my research group has secured a total external research funding of ~2.2 million dollars to UNL. The funding has provided full or partial financial support for 2 postdoctoral researchers, 5 M.S. students, 3 Ph.D. students, and 10+ undergraduates. The research program has also attracted two 1-year visiting scholars that have been working at UNL since early 2012, respectively under the support from the Hong Kong Polytechnic University and Chinese Research Council under the management of Chinese National Science Foundation. 2. RESEARCH ACCOMPLISHMENT 2.1 Satellite/Ground-based Remote Sensing I have been using a variety of satellite sensors and ground-based measurements to characterize the aerosol optical properties, radiative forcing, and atmospheric radiative transfer [Wang et al., 2004a; Wang and Martin, 2007]. Because the number of routine measurements of aerosols is limited, satellite remote sensing is the only feasible tool to monitor globally the source, movement, and distribution of atmospheric aerosols. I have developed algorithms and numerical tools for retrieval of aerosol optical thickness from geostationary satellites operated by the U.S. and Japan [Wang et al., 2003a; 2003b], as well as from polar orbiting satellites aboard the NASA’s Earth Observation System platform [Wang et al., 2010]. Aerosol optical thickness, in the first order, is an indicator of the 1/14 columnar mass of atmospheric particulates. I was among the first to use satellite data to monitor the air quality from space, as shown in Wang and Christopher [2003], a paper that has received 100+ citations to date. One novel concept that I developed of using geostationary satellite to study the phase function and shape of atmospheric particles [Wang et al., 2003c] is also of high research interest in the preparation of one of NASA’s decadal missions, the Geostationary Coastal and Air Pollution Events mission (GEO-CAPE). 2.2 Data-Assimilation Modeling oF Aerosols Satellite data can only tell us the current and past distribution of atmospheric aerosols. Key to the benefits of our daily lives (including the aviation, ground transportation, and public health) are the forecast of atmospheric aerosols, from which the visibility and air quality can be predicted. However, to predict aerosol distribution in tomorrow, we must first characterize how aerosols are distributed today. In this regard, it is a must to assimilate the satellite data into the air quality models, so that the today’s aerosol distribution can be well specified for model to make accurate forecast for tomorrow. To this end, I have developed the software named “Assimilation and Radiation Online Modeling of Aerosols (AROMA)” for the Regional Atmospheric Modeling System (RAMS). This module has been used to assimilate the satellite-derived aerosol optical thickness into the RAMS-AROMA to quantify the transport of Saharan dust to the each coast of the United States, the radiative effect of dust on surface temperature and marine meteorology [Wang et al., 2004b]. Funded by NASA, RAMS- AROMA model together with other aerosol products was also used to study the impact of air quality and climate of long-range transported Central American smoke aerosols over the southeastern U.S. [Wang et al., 2006; Wang and Christopher, 2006; Wang et al., 2009]. Recently, our group has also used the Weather Research and Forecasting model with Chemistry (WRF-Chem), the latest generation of meteorology-chemistry coupled numerical and regional model, in conduction with the space-borne lidar data to study the injection height of smoke particles during the biomass burning season in South Asia Maritime Continent [Wang et al., 2012b]. These modeling studies provided us an improved understanding of smoke transport pathway in the atmosphere, and suggested the importance of assimilating hourly emission into the model toward a more reliable prediction of smoke transport. In addition, a new approach are also developed that combines satellite observations with the inverse modeling technique to study the dust emission in the East Asia [Wang et al., 2012a]. Better estimate of dust emissions in Asia can help us to quantify the amount of the dust particles that are transported from Asia to the west coast of U.S., which has important implications for emission control policy and regional climate prediction. 2.3 CHemistry Transport Modeling oF Aerosols Atmospheric aerosols are not only affected by meteorology, but also regulated by the atmospheric chemistry. Gas-to-particle conversion is common in the atmosphere; for example, sulfur dioxide (in gas phase) emitted from power plants can be oxidized in the atmosphere to from sulfuric acid particles (in liquid phase) within a day. Ammonia gases from agriculture sources can meet with sulfuric acid and together form the ammonium sulfate particles (in solid phase in low relative humidity conditions). Hence, studying the chemical processes associated with the aerosols is also an integral part of my research. I have developed module to simulate the sulfate solid-aqueous phase transition in the atmosphere [Wang et al., 2008], and studied the impact of androgenic sulfate aerosols on climate [Wang et al., 2008b]. 2/14 2.4 Build A ResearcH Team At the time of this writing, my research group consists of 2 postdoctoral researchers, 9 graduate students (3 Ph.D. student), 2 undergraduates, and 2 visiting scholars. More than 10 undergraduate students were hired in last 3 years in my group as research assistants to support various research projects. It is of my highest research priority to attract talented undergraduates into science field, and to train the graduate students and build a research team to conduct the cutting-edge research here at UNL. In the last 5 years, 3 students under my supervision graduated with a M.S. degree, and two students under my supervision received the prestigious NASA graduate fellowship (through national competition) to support their Ph.D. work. 5 articles (either published, accepted, or submitted) are led by the graduate students under my supervision [Peterson et al., 2009, 2012; Peterson and Wang, 2012; Anderson et al., 2012; Holt and Wang, 2012], and other 3 peer-reviewed articles are coauthored by the graduate students [Wang et al., 2010; Wang et al., 2012a; Wang et al.; 2012b]. 3. ONGOING FUNEDED RESEARCH My current research not only continues in the area of combining satellite remote sensing and numerical models to study air quality, but also expands to the area of aerosol-cloud interaction, fire weather, radiative impact of volcanic aerosols, remote sensing of aerosols using data from ground- based network for the NASA’s Glory satellite mission (http://glory.gsfc.nasa.gov/) and the Suomi National Polar-orbiting Partnership (NPP) mission, a preparatory project for nation’s Joint Polar Satellite System (JPSS, http://www.nesdis.noaa.gov/jpss/ ). JPSS is planned to provide global satellite observation needed for weather and climate prediction in the next 10-20 years. 3.1 EFFect oF Smoke Aerosols on Regional Air Quality and Climate The projects are to conduct statistical