Chemistry-climate working group2013-2017 Co-chairs: Hong Liao, Shiliang Wu

The 7th International GEOS-Chem Meeting (IGC7)

Chemistry-climate interactions

ClimateAtmospheric

Chemistry

Ecosystems

Interactions on interannual, decadal, or centennial time scales

Radiative forcing by GHGs,O3, and aerosols

Changes in emissions,chemical reactions, transport,and deposition

Depositionof O3, N, S, etc.

Biogenic VOCs,fire emissions, etc.

Impacts on landcover, etc.

Carbon cycle, etc.

Assimilated meteorologyGEOS-4, GEOS-5, MERRA

GEOS-Chem

Land cover model

Archived meteorology

Fire prediction model

Climate models

Model frameworks

1. Standard

2. Global Change and Air Pollution (GCAP)

Impacts of climate change on land cover (biogenic emissions),fire emissions, and atmospheric chemistry.

Impacts of climate variability on atmospheric chemistry on interannual to decadal time scales.

GEOS-Chem

The standard GEOS-Chem has been used to understand historical changes in atmospheric Chemistry

• To quantify the variations in chemical species;

• To understand the drivers (meteorological parameters vs. emissions) of the variations of different species;

• To help with the interpretation of year-by-year variations in measurements;

• To assess the effectiveness of short-term air quality control strategies.

Mu and Liao, 2014Yang et al., 2014Yang et al., 2015

The GCAP model framework can be used to investigate past and future atmospheres

Three versions of GCAP are available:

1. GISS Model 3 + GEOS-Chem (4o x 5o, by Loretta Mickley in year 2003)

2. GISS Model E + GEOS-Chem (2o x 2.5o or 4o x 5o, by L. T. Murray and E. M. Leibensperger in year 2014)

3. CESM + GEOS-Chem (2o x 2.5o, by Rokjin Park in year 2014)

GCAP has been used extensively for projection of future air quality

1. GCAP: Future changes in air quality and tranboundary transport

Wang et al., 2013; Jiang et al., 2013; Wai et al., 2014

2. GCAP + changes in land cover

Wu et al., 2012; Tai et al., 2013.

3. GCAP + changes in fire emissions

Yue et al., 2013; 2014

2000-2050 increase in surface ozone over Asia due to changes in emissions + climate. Wang et al., 2013.

2050s – present-day

Past fire emissions

Sensitivity of biogenic isoprene emissions to atmospheric [CO2]

Isoprene photochemistry

HO2 uptake by aerosols

Lightning NOx emissions

Murray et al., 2014; Achakulwisut, in review.

[GHGs] Orbital parameters Topography Sea ice extent Sea surface temp.

Climate

GISS Model E GCM

Meteorological fields for 4 time-slices: Present day: ca. 1990sPre-industrial: ca. 1770swarm LGM: ~21kacold LGM: ~21ka

GCAP2 has been applied to paleo- and preindustrial simulations

GCAP3

GACP 3 has been used to study future O3 and oxidants under the RCPs

Kim et al., 2015

RCP2.6 O3 2050-2000 RCP4.5 O3 2050-2000

RCP6.0 O3 2050-2000 RCP8.5 O3 2050-2000

Updates in GEOS-Chem that are important for chemistry-climate

Online radiative transfer model --- The Rapid Radiative Transfer Model for GCMs (RRTMG) has been coupled online with the GEOS-Chem model as described by Heald et al. (2014);

--- The RRTMG solves the radiative transfer equation in shortwave bands and 16 longwave bands that cover from 230 nm through 56 μm.

RCP future emission scenarios in GEOS-Chem (Holmes et al., 2013)

Heald et al. (2014)

Future directions: The two-way coupling of chemistry-climate

1. Coupling of the grid-independent GEOS-Chem with climate models will allow us to easily link chemistry with climate, vegetation, ocean biology, fire, carbon cycle .

2. On-line interface between GEOS-Chem and the Goddard Earth Observing System (GEOS) Earth System Model from the NASA Global Modeling and Assimilation Office (GMAO) is ready, using the Earth System Modeling Framework (ESMF);

3. Can the GEOS-Chem simulations be conducted on any model grid and interfaced with any ESM?