Chemistry-climate interactions: a new direction for GEOS-CHEM GEOS-CHEM research to date GCAP project 1993 2003 2050 Current project: drive GEOS-CHEM into the future with GISS GCM III.
Previous chemistry-climate work at Harvard used the CACTUS model. CACTUS (Chemistry, aerosol, climate: Tropospheric unified simulation)Collaborators: Caltech, GISS, Irvine, Carnegie Mellon, Georgia Tech GHGs, solar flux, land surface, etc. GISS GCM II’ meteorology aerosol ozone CalTech aerosol module Harvard chemistry module aerosol oxidants, nitric acid emissions emissions
GEOS-CHEM studies of natural emissions are consistent with studies of preindustrial ozone in CACTUS model. Standard model Observations Adjusted model • Best match with observed surface ozone: • Increased isoprene emissions by 50% • Lightning NOx scaled to 1.0 Tg/y Mickley et al., 2001
Number of summer days with 8-hour ozone > 84 ppbv, average for northeast U.S. sites days 1988, hottest on record In 2003, we started GCAP (Global Climate and Air Pollution).collaborators: David Streets, John Seinfeld, David Rind, Joshua Fu Basic question: how will surface air quality respond as climate changes? • Many meteorological factors control air quality, e.g.: • Temperature • Ventilation • Circulation patterns • Rainfall • Cloudiness Lin et al., 2001 Work so far: CACTUS model with tracers of anthropogenic pollution.
GCAP approach: archive met fields from GISS GCM and apply to GEOS-CHEM 23L GISS GCM (Model 3), with changing GHGs 1950 2000 2025 2050 2075 2100 Spin-up of ocean archived temperatures, humidity, winds, etc GEOS-CHEM Calculates chemistry, aerosol CMAQ regional model precursor emissions
Interface completed Validation ongoing GCAP Progress New version frozen 23L GISS GCM (Model 3), with changing GHGs 1950 2000 2025 2050 2075 2100 Spin-up of ocean archived temperatures, humidity, winds, etc Interface ~done Future emissions prepared GEOS-CHEM CMAQ regional model Interface completed precursor emissions
New EPA-STAR project, 2005: “GCAP + Fire”collaborators: Jennifer Logan, David Diner, Daewon Byun How will changing fire frequency in the future affect surface air quality? 23L GISS GCM withfire prediction scheme 1950 2000 2025 2050 2075 2100 Spin-up of ocean archived met fields and areas burned GEOS-CHEM Calculate chemistry, aerosol CMAQ regional model precursor emissions
Progress so far • New version of GISS GCM 23-layer received (Model III), includes new boundary layer scheme. (David Rind). • Tracers tested in Model III (David Rind). • GISS meteorological fields implemented into GEOS-CHEM. (Loretta Mickley, Shiliang Wu) • GEOS-CHEM results for present-day validated. (Shiliang Wu). • Interface between GEOS-CHEM and CMAQ tested. (Joshua Fu). • Future emission inventories completed. (David Streets).
1950 2000 2025 2050 2075 2100 Spin-up of ocean GCAP continued. . . 23L GISS GCM, with changing GHGs archived met fields 2. Recalculate meteorology with ozone, aerosol trends GEOS-CHEM 1. Develop future climatology for ozone and aerosols 2000 2025 2050 2075 2100