Grantee Research Project Results
2021 Progress Report: Improving chemical mechanisms for regional/global models in support of US air quality management: application to the GEOS-Chem model
EPA Grant Number: R840014Title: Improving chemical mechanisms for regional/global models in support of US air quality management: application to the GEOS-Chem model
Investigators: Jacob, Daniel J.
Institution: Harvard University
EPA Project Officer: Chung, Serena
Project Period: August 1, 2020 through July 31, 2023 (Extended to July 31, 2024)
Project Period Covered by this Report: August 1, 2020 through July 31,2021
Project Amount: $785,010
RFA: Chemical Mechanisms to Address New Challenges in Air Quality Modeling (2019) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:
This project will unify, improve, and condense the chemical mechanisms used in the GEOS-Chem global/regional model for air quality applications. Specific objectives include: (1) implementation of a common model framework for the different GEOS-Chem chemical mechanisms to facilitate their merging, subsetting, and updating; (2) improvement of current mechanisms for halogen, mercury, and volatile organic compounds (VOCs) chemistry; (3) speed-up of the chemical calculation through adaptive mechanism reduction and machine learning methods; (4) updated estimates of background influences on US air quality.
Progress Summary:
- We have developed, implemented into GEOS-Chem, and published (or submitted for publication) new model mechanisms for halogen chemistry [Wang et al., 2021], mercury chemistry [Shah et al., 2021], aromatic chemistry [Bates et al., 2021a], methanol chemistry [Bates et al., 2021b], and cloud acidity [Shah et al., 2020]. The halogen mechanism and the cloud acidity mechanisms were brought into standard GEOS-Chem version 12.9.0.
- We have developed and published a new adaptive implementation of the Kinetic Pre-Processor (KPP) numerical solver for chemical mechanisms that allows chemical transport models such as GEOS-Chem to select an appropriately compact submechanism locally and on the fly [Shen et al., 2021]. We have developed and published a prototype neural-network machine learning algorithm for numerical solution of chemical mechanisms [Kelp et al., 2020].
Future Activities:
- Implement the new mechcanisms for mercury, aromatic VOCs, and methanol in the standard GEOS-Chem model;
- Develop a new mechanism for isoprene SOA;
- Develop a new mechanism for chemical recycling of aerosol nitrate to NOx;
- Develop a more flexible version of the Shen et al. (2021) adaptive numerical solver and implement it in the standard GEOS-Chem model;
- Unify gas- and aerosol-phase GEOS-Chem chemistry under KPP;
- Modularize the GEOS-Chem version of KPP to enable independent use across models including adoption of the new mechanisms developed under this grant;
- Explore the stability of machine-learned chemical solvers for long-term global air quality simulations;
- Apply our new mechanisms to investigation of background influence on US air quality.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 13 publications | 13 publications in selected types | All 13 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Bates K, Jacob D, Li K, Ivatt P, Evans M, Yan Y, Lin J. Development and evaluation of a new compact mechanism for aromatic oxidation in atmospheric models. Atmospheric Chemistry and Physics 2021;21(24):18351-18374. |
R840014 (2021) R840014 (2023) |
Exit Exit |
|
Kelp M, Jacob D, Lin H, Sulprizio M. An online-learned neural network chemical solver for stable long-term gobal simulations of atmospheric chemistry. Journal of Advances in Modeling Earth Systems 2022;14(6). |
R840014 (2021) R840014 (2023) |
Exit Exit |
Supplemental Keywords:
Air quality modeling, GEOS-Chem, halogen chemistry, mercury chemistry, isoprene chemistry, numerical methods, chemical solvers, machine learning methods, backgroundRelevant Websites:
Atmospheric Chemistry Modeling Group - Harvard University Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.