Presenter: Manish Shrivastava

Title: Development and evaluation of complex but computationally efficient treatments of secondary organic aerosols (SOA) within the Energy Exascale Earth System Model (E3SM)

Abstract: Secondary organic aerosols (SOA) are formed in the atmosphere by oxidation of organic gases emitted from natural biogenic, anthropogenic, and biomass burning sources. In many regions of the atmosphere, SOA greatly contributes to fine particle mass loadings and number concentrations and affects clouds and radiation. For computational efficiency, global models use simplified SOA treatments, which often do not capture the dynamics of SOA formation. Here we develop more complex but computationally efficient SOA treatments within the global Energy Exascale Earth System Model (E3SM) to investigate how simulated SOA spatial distributions respond to some of the important but uncertain processes affecting SOA chemical formation, removal, and lifetime. We evaluate model predictions with a suite of surface, aircraft, and satellite observations that span the globe and the full troposphere.

Integrating insights from global atmospheric modeling and measurements, we show that strong chemical production achieved by multigenerational chemistry including moderate fragmentation of SOA precursors and strong chemical sinks represented by particle-phase photolysis are needed to explain the aircraft-observed vertical profiles of SOA over multiple regions including North America, equatorial oceans, and the Southern Ocean. Photolysis reduces simulated global SOA lifetimes from 10 to 3 days. Within the same model physics and cloud treatments, we show that changes in SOA chemistry formulations change SOA wet removal lifetimes by a factor of 3. Simulations show that SOA exerts a strong effective radiative forcing (PD-PI) at the top of atmosphere ranging from −0.1 to −0.4 W m-2. Our work develops a framework that enables explicit coupling of complex SOA chemistry with processes related to energy and land use, which are missing in many global models, and is important to assess future aerosol impacts on clouds and radiative forcing.

Date

16 Sep 2021

Time

PT: 8:30 am
ET: 11:30 am

Call Info

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Attendees

Presentation

Time	Title	Presenter	Presentation	Recording	Notes
30 min	Development and evaluation of complex but computationally efficient treatments of secondary organic aerosols (SOA) within the Energy Exascale Earth System Model (E3SM)	Manish Shrivastava	Shrivastava_E3SM_BGC_Seminar.pptx	MP4 Movie (on the E3SM YouTube Channel)

Time

Title

Presenter

Presentation

Recording

Notes

30 min

Development and evaluation of complex but computationally efficient treatments of secondary organic aerosols (SOA) within the Energy Exascale Earth System Model (E3SM)

Manish Shrivastava

Shrivastava_E3SM_BGC_Seminar.pptx

MP4 Movie (on the E3SM YouTube Channel)