Asian Long-Range Transport Linkage to Atmospheric River Events in California

California attributes most of its rainfall to atmospheric river (AR) events during the cool months (October- March). 2017, in particular, is one of the wettest years to date and brought California out of its State of Emergency drought. While the recent rain alleviated drought conditions, the intense precipitation resulted in flooding of cities and freeways, mudslides and mountain trail erosions, destruction of property, and contamination of water supplies; all of which threaten public safety. In order to improve precipitation forecasts and prepare for such disasters, it is essential to understand the dynamics and characteristics of atmospheric phenomena that contribute to these precipitation amounts. The proposed study will examine the properties of the last three AR events (1/8/2017, 1/10/2017, and 2/19/2017) to quantify the uncertainty and ask to what degree can the correlation of precipitation intensity from these ARs be attributed to the long-range transport of aerosols and greenhouse gases from the Asian continent across the Northern Pacific Ocean. Satellite data from MODIS and CALIPSO will be used for AR and aerosol observations, as well as distinguishing between aerosol layers. WRF-Chem will be used to model forward aerosol trajectories from the Asian continent to California, while MERRA2 and NCEP reanalysis data will be used for back trajectories of aerosols and greenhouse gases from California.