Embed Size (px)
Citation preview
Aerosol Working Group
The 6th International GEOS-Chem User’s Meeting May 6, 2013
Aerosol WG Co-Chairs: Colette L. Heald Jeff Pierce
([email protected]) ([email protected])
To join email list send email to: [email protected]
Why Aerosols in GEOS-Chem? Air Quality
Ecosystem Health
Climate
Local Visibility LRT
Acid Rain Nutrients
Why in GEOS-Chem rather than stand-alone aerosol model? Benefits from coupled oxidant simulation, enables multi-pollutant approach.
Why Aerosols (if I really only care about gas-phase)?
Heterogeneous Chemistry
Effect on Photolysis Rates [Martin et al., 2003]
Original: [Martin et al., 2003] N2O5: [Evans and Jacob, 2005] HO2: [Thornton et al., 2008]
Gas-Particle Partitioning ISORROPIA II: [Foutoukis and Nenes, 2007] Implementation in GC: [Pye et al., 2009]
The History of Aerosols in GEOS-Chem
Carbonaceous Aerosols and Sulfate-Nitrate Ammonium based on GOCART
[Park et al., 2003] [Park et al., 2004]
Sea Salt Dust (DEAD Scheme with SOA (2-product, biogenic GOCART source map) & anthropogenic)
[Alexander et al, 2005; Jaeglé et al., 2011]
[Fairlie et al., 2007] [Liao et al., 2007; Henze et al., 2008]
• mass based scheme, assumes log-normal size distributions • full-chemistry with or without SOA (only without is benchmarked), also aerosol-only
Sectional Scheme Option: TOMAS TwO-Moment Aerosol Sectional microphysics scheme
(maintained by Sal Farina, Dan Westervelt, Jeff Pierce and Peter Adams)
• Explicit simulation of the aerosol size distribution. • Aerosol/climate effects and aerosol-size/heath effects
Features •Aerosol number and mass simulated in 30 size sections, with explicit aerosol number balance (can construct number budget) •All GEOS-Chem aerosol species incorporated into size sections • Sulfate, primary OC, SOA, EC, sea salt, dust
In the Pipeline: • parallelization • tagging • different size-section versions: 12 (speed) and 40 (precision)
Sectional Scheme Option: APM Advanced Particle Microphysics scheme
(maintained by Gan Luo and Fangqun Yu)
Secondary particles (SP) : 40 bins
Sea salt particles: 20 bins
Dust: 15 bins
BC and Primary OC: 8 log-normal modes
Coating of primary particles by secondary species explicitly simulated.
Modeled particle size distribution at Hyytialla, Finland • Size-resolved microphysics with variable size resolution for particles of different types and sizes
• Computing cost (for 1 year simulation) (2ox2.5o, 47 layers, on 24-core workstation)
Original model, 59 tracers, ~ 5 day With APM, 59+88 = 147 tracers
no radiative forcing calculation: ~ 11 days with radiative forcing calculation: ~ 13.5 days
• Recent advances (1) Integrated AER RRTMG with GEOS-Chem/APM (2) Participated in AeroCom II aerosol direct
radiative forcing intercomparison (Myhre et al., ACP, 2013; Stier et al., ACP, 2013)
(3) Implemented schemes to calculate first aerosol indirect radiative forcing
• Plans (1) Move new features developed in a previous
version (v8.3.2) to new version and submit the code to the GEOC-Chem support team
(2) Continue to study aerosol-radiation-chemistry-cloud-climate interaction and evaluate results
Research Topics Being Investigated in the WG
• Aerosol chemistry (eg. sulfate formation, SOA) • Black carbon • Regional AQ • Historical aerosol trends, future aerosol projections (AQ and climate) • Satellite-based PM2.5 estimation • Long range transport and impacts • Precursor emission estimation, including for new satellite products (eg. NH3, SO2) • Estimating associated health impacts • Aerosol microphysics: new particle formation, indirect effect, geoengineering • Removal processes
GEOS-5 10km aerosol model
Progress since IGC5
Updated sea salt emission scheme [Jaeglé et al., 2011], v9-01-03
Dust sub-micron size for optics [Ridley et al., 2011], v9-01-03
Using GEOS-5 LWC for aqueous sulfate chemistry and NH3 seasonality for Asia [Fisher et al., 2011], v8-03-02
BC/OC emissions from Bond [Leibensperger et al., 2011], v8-03-02
Aerosol optics update: sizes [Drury et al., 2010; Jaeglé et al., 2011], 550 nm AOD, multi-wavelengths in jv_spec_aod.dat [Heald and Martin], v8-03-01
Implementation of ISORROPIA II [Pye et al., 2009], v8-03-01
Aromatic SOA [Henze et al., 2008], v8-03-01
+ other general emissions, deposition updates
Recent Progress: Integration of RRTMG
1750 Now
Clear-Sky TOA (SW+LW) Radiative Fluxes (2004), RF including FF only
Change in Aerosol = Radiative Forcing
~ -0.4 W/m2 Radiative Effect
~ -2.5 W/m2
[Heald, Ridley et al., in prep]
Online coupling: use of consistent optics & clouds at high temporal resolution Identified as a priority at IGC5, collaboration between MIT (Heald, Barrett) and AER LW, SW, clear-sky and all-sky forcing from speciated aerosols, O3 and methane
Important Capabilities in the Pipeline
• Updates to SOA simulation + option for semi-volatile POA and IVOC (Pye, v9-2) • Uptake of SO2, HNO3 and H2SO4 on mineral dust (Fairlie, v9-2) • Cloudwater pH for sulfate formation (Alexander, v9-2) • RRTMG online (Ridley/Heald, v9-3) • TOMAS parallelization (Pierce, v9-3)
Challenges Ahead, Topics for Discussion
• Maintaining 3rd party code (TOMAS, APM, RRTMG) • Full integration of gas and particle phase chemical mechanism • Modernizing aerosol optics • The future of SOA (multiple options?) • Others??
