Novel Use of Satellite Data to Explore Relationships between Land Surface Conditions and Air Quality

Various natural and anthropogenic factors modify land surface conditions which redefine the sources of natural emissions, and alter the variability in atmospheric weather and chemistry. In selected cases, we show that novel use of satellite land products can help interpret the variability in atmospheric composition, as well as improve weather and air quality modeling analyses through better representing the land-atmosphere interactions. First, for the western US (particularly in Arizona), we extend the records of dynamic dust emission source areas based on satellite land cover and vegetation index products, as well as the frequency and intensity of dust events based on in-situ and satellite aerosol measurements. The temporal changes of dust emission source areas and dust activity are interpreted by the dynamics of land surface (e.g., soil moisture and vegetation) and atmospheric weather conditions (e.g., winds). We then show first results of assimilating NASA's Soil Moisture Active-Passive (SMAP) soil moisture data to benefit the coupled NUWRF-Chem (NASA Unified Weather Research and Forecasting model with Chemistry) air quality modeling, during the Korea-US Air Quality Field Study (KORUS-AQ) over East Asia in Spring 2016. With SMAP assimilation included, water vapor and air pollution transport from northern-central China "transitional climate zones" to South Korea is better represented in NUWRF-Chem during two studied pollution events. The magnitude and spatial distribution of improvement vary under different synoptic conditions. Future directions on investigating land-atmospheric weather-composition interactions will be discussed, including feedback from the recent International Surface Working Group meeting.