ACCLIP: Asian Summer Monsoon Chemical and CLimate Impact Project

Summary

The Asian Summer Monsoon (ASM) is the largest meteorological pattern in the Northern Hemisphere (NH) summer season. Persistent convection and the large anticyclonic flow pattern in the upper troposphere and lower stratosphere (UTLS) associated with ASM produces a prominent enhancement of chemical species of pollution and biomass burning origins in the UTLS. The monsoon convection occurs over South, Southeast, and East Asia, a region of uniquely complex and rapidly changing emissions tied to both its high population density and significant economic growth. The coupling of the most polluted boundary layer on Earth to the largest dynamical system in the summer season through the deep monsoon convection has the potential to create significant chemical and climate impacts. An accurate representation of the ASM transport, chemical and microphysical processes in chemistry-climate models is much needed for characterizing ASM chemistry-climate interactions and for predicting its future impact in a changing climate. ACCLIP will be focused on 1) investigating the transport pathway of the ASM uplifted air from inside of the anticyclone to the global UTLS, 2) sampling the chemical content of air processed in the ASM to ascertain its role in UTLS ozone chemistry, and in re-distributing active species and short-lived climate forcers (SLCFs), to examine the roles of Asian pollution and monsoon strength in chemistry and climate, and to understand two-way coupling between chemistry and climate, 3) obtaiing information on aerosol size, mass and chemical composition necessary for determining the radiative impact of the ASM, for constraining models of aerosol formation and for contrasting the organic-rich ASM UTLS aerosol population with that of sulfate-rich volcanic plumes and the background aerosol population, and 4) measuring the water vapor distribution associated with the monsoon dynamical structure to evaluate transport across the tropopause, and determine the role of the ASM in water vapor transport into the stratosphere.The NSF/NCAR GV and NASA WB-57 aircraft will be fully outfitted with the state-of-the-art sensors needed to collect the measurements to examine these issues.