Chemistry Across Multiple Phases (CAMP) version 1.0: An integrated multi-phase chemistry model

Abstract. A flexible treatment for gas- and aerosol-phase chemical processes has been developed for models of diverse scale, from box models up to global models. At the core of this novel framework is an "abstracted aerosol representation" that allows a given chemical mechanism to be solved in atmospheric models with different aerosol representations (e.g., sectional, modal, or particle-resolved). This is accomplished by treating aerosols as a collection of condensed phases that are implemented according to the aerosol representation of the host model. The framework also allows multiple chemical processes (e.g., gas- and aerosol-phase chemical reactions, emissions, deposition, photolysis, and mass-transfer) to be solved simultaneously as a single system. The flexibility of the model is achieved by (1) using an object-oriented design that facilitates extensibility to new types of chemical processes and to new ways of representing aerosol systems; (2) runtime model configuration using JSON input files that permits making changes to any part of the chemical mechanism without recompiling the model; this widely used, human-readable format allows entire gas- and aerosol-phase chemical mechanisms to be described with as much complexity as necessary; and (3) automated comprehensive testing that ensures stability of the code as new functionality is introduced. Together, these design choices enable users to build a customized multiphase mechanism, without having to handle pre-processors, solvers or compilers. Removing these hurdles makes this type of modeling accessible to a much wider community, including modelers, experimentalists, and educators. This new treatment compiles as a stand-alone library and has been deployed in the particle-resolved PartMC model and in the MONARCH chemical weather prediction system for use at regional and global scales. Results from the initial deployment to box models of different complexity and MONARCH will be discussed, along with future extension to more complex gas--aerosol systems, and the integration of GPU-based solvers.

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libcloudph++ 2.0: aqueous-phase chemistry extension of the particle-based cloud microphysics scheme

Geoscientific Model Development ◽

10.5194/gmd-11-3623-2018 ◽

2018 ◽

Vol 11 (9) ◽

pp. 3623-3645 ◽

Cited By ~ 4

Author(s):

Anna Jaruga ◽

Hanna Pawlowska

Keyword(s):

Aqueous Phase ◽

Numerical Models ◽

Cloud Condensation Nuclei ◽

Cloud Microphysics ◽

Chemical Processes ◽

Cloud Droplets ◽

Microphysics Scheme ◽

Phase Oxidation ◽

Phase Chemistry ◽

Phase Chemical

Abstract. This paper introduces a new scheme available in the library of algorithms for representing cloud microphysics in numerical models named libcloudph++. The scheme extends the particle-based microphysics scheme with a Monte Carlo coalescence available in libcloudph++ to the aqueous-phase chemical processes occurring within cloud droplets. The representation of chemical processes focuses on the aqueous-phase oxidation of the dissolved SO2 by O3 and H2O2. The particle-based microphysics and chemistry scheme allows for tracking of the changes in the cloud condensation nuclei (CCN) distribution caused by both collisions between cloud droplets and aqueous-phase oxidation. The scheme is implemented in C++ and equipped with bindings to Python. The scheme can be used on either a CPU or a GPU, and is distributed under the GPLv3 license. Here, the particle-based microphysics and chemistry scheme is tested in a simple 0-dimensional adiabatic parcel model and then used in a 2-dimensional prescribed flow framework. The results are discussed with a focus on changes to the CCN sizes and comparison with other model simulations discussed in the literature.

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Gaseous chemistry and aerosol mechanism developments for version 3.5.1 of the online regional model, WRF-Chem

Geoscientific Model Development ◽

10.5194/gmd-7-2557-2014 ◽

2014 ◽

Vol 7 (6) ◽

pp. 2557-2579 ◽

Cited By ~ 30

Author(s):

S. Archer-Nicholls ◽

D. Lowe ◽

S. Utembe ◽

J. Allan ◽

R. A. Zaveri ◽

...

Keyword(s):

Gas Phase ◽

Chemical Mechanism ◽

Reduced Form ◽

Sea Spray ◽

Wind Fields ◽

Aerosol Composition ◽

Aerosol Emission ◽

Sea Spray Aerosol ◽

The Impact ◽

Phase Chemical

Abstract. We have made a number of developments to the Weather, Research and Forecasting model coupled with Chemistry (WRF-Chem), with the aim of improving model prediction of trace atmospheric gas-phase chemical and aerosol composition, and of interactions between air quality and weather. A reduced form of the Common Reactive Intermediates gas-phase chemical mechanism (CRIv2-R5) has been added, using the Kinetic Pre-Processor (KPP) interface, to enable more explicit simulation of VOC degradation. N2O5 heterogeneous chemistry has been added to the existing sectional MOSAIC aerosol module, and coupled to both the CRIv2-R5 and existing CBM-Z gas-phase schemes. Modifications have also been made to the sea-spray aerosol emission representation, allowing the inclusion of primary organic material in sea-spray aerosol. We have worked on the European domain, with a particular focus on making the model suitable for the study of nighttime chemistry and oxidation by the nitrate radical in the UK atmosphere. Driven by appropriate emissions, wind fields and chemical boundary conditions, implementation of the different developments are illustrated, using a modified version of WRF-Chem 3.4.1, in order to demonstrate the impact that these changes have in the Northwest European domain. These developments are publicly available in WRF-Chem from version 3.5.1 onwards.

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Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-5289-2009 ◽

2009 ◽

Vol 9 (2) ◽

pp. 5289-5320 ◽

Cited By ~ 1

Author(s):

D. Lowe ◽

D. Topping ◽

G. McFiggans

Keyword(s):

Boundary Layer ◽

Gas Phase ◽

Condensed Phase ◽

Significant Influence ◽

Marine Boundary Layer ◽

Turnover Rates ◽

Gas Phase Chemistry ◽

Size Dependent ◽

Multi Phase ◽

Phase Chemistry

Abstract. A coupled box model of photochemistry and aerosol microphysics which explicitly accounts for size-dependent chemical properties of the condensed-phase has been developed to simulate the multi-phase chemistry of chlorine, bromine and iodine in the marine boundary layer (MBL). The model contains separate seasalt and non-seasalt modes, each of which may be composed of 1–16 size-sections. By comparison of gaseous and aerosol compositions predicted using different size-resolutions with both fixed and size-dependent aerosol turnover rates, it was found that, for halogen-activation processes, the physical property initialisation of the aerosol-mode has a significant influence on gas-phase chemistry. Failure to adequately represent the appropriate physical properties can lead to substantial errors in gas-phase chemistry. The size-resolution of condensed-phase composition has a less significant influence on gas-phase chemistry.

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Radical mechanisms of methyl vinyl ketone oligomerization through aqueous phase OH-oxidation: on the paradoxical role of dissolved molecular oxygen

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-2913-2013 ◽

2013 ◽

Vol 13 (1) ◽

pp. 2913-2954 ◽

Cited By ~ 2

Author(s):

P. Renard ◽

F. Siekmann ◽

A. Gandolfo ◽

J. Socorro ◽

G. Salque ◽

...

Keyword(s):

Aqueous Phase ◽

High Resolution Mass Spectrometry ◽

Organic Aerosol ◽

Vinyl Ketone ◽

Methyl Vinyl Ketone ◽

Chemical Mechanism ◽

Methyl Vinyl ◽

Phase Chemistry ◽

Dissolved O2

Abstract. It is now accepted that one of the important pathways of Secondary Organic Aerosol (SOA) formation occurs through aqueous phase chemistry in the atmosphere. However, the liquid phase chemical mechanisms leading to macromolecules are still not well understood. For α-dicarbonyl precursors, such as methylglyoxal and glyoxal, radical reactions through OH-oxidation produce oligomers, irreversibly and faster than accretion reactions. Methyl vinyl ketone (MVK) was chosen in the present study as it is an α, β-unsaturated carbonyl that can undergo such reaction pathways in the aqueous phase and forms even high molecular weight oligomers. We present here experiments on the aqueous phase OH-oxidation of MVK, performed under atmospheric relevant conditions. Using NMR and UV absorption spectroscopy, high and ultra-high resolution mass spectrometry, we show that the fast formation of oligomers up to 1800 Da is due to radical oligomerization of MVK, and 13 series of oligomers (out of a total of 26 series) are identified. The influence of atmospherically relevant parameters such as temperature, initial concentrations of MVK and dissolved oxygen are presented and discussed. In agreement with the experimental observations, we propose a chemical mechanism of OH-oxidation of MVK in the aqueous phase that proceeds via radical oligomerization of MVK on the olefin part of the molecule. This mechanism highlights the paradoxical role of dissolved O2: while it inhibits oligomerization reactions, it contributes to produce oligomerization initiator radicals, which rapidly consume O2, thus leading to the supremacy of oligomerization reactions after several minutes of reaction. These processes, together with the large ranges of initial concentrations investigated (60–656 μM of dissolved O2 and 0.2–20 mM of MVK) show the fundamental role that O2 likely plays in atmospheric organic aerosol.

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Incorporation and evaluation of the CRI v2.2 chemical mechanism in UKESM1: An alternative mechanism with updated isoprene chemistry for investigating the influence of BVOCs on atmospheric composition and climate.

10.5194/egusphere-egu21-1236 ◽

2021 ◽

Author(s):

James Weber ◽

Scott Archer-Nicholls ◽

N. Luke Abraham ◽

Youngsub M. Shin ◽

Thomas Bannan ◽

...

Keyword(s):

Peroxy Radical ◽

Tropospheric Chemistry ◽

Chemical Mechanism ◽

Atmospheric Composition ◽

Radiation Budget ◽

Alternative Mechanism ◽

Mixing Ratios ◽

The United Kingdom ◽

Surface Mixing ◽

Phase Chemistry

We present the first incorporation and evaluation of the Common Representative Intermediates version 2.2 chemistry mechanism, CRI v2.2, for use in the United Kingdom Earth System Model (UKESM1). Tuned against the MCM v3.3.1, the CRI v2.2 mechanism builds on the previous CRI version, CRI v2.1, in UKESM1 (Archer-Nicholls et al., 2020) by updating isoprene chemistry and offers a more comprehensive description of tropospheric chemistry than the standard chemistry mechanism STRAT-TROP (ST).CRI v2.2 adds state-of-the-art isoprene chemistry with the introduction of HOx-recycling via the isoprene peroxy radical isomerisation pathway, making UKESM1 one of the first CMIP6 models to include this important chemistry. HOx-recycling has noticeable effects on oxidants in regions with large emissions of biogenic volatile organic compounds (BVOCs). Low altitude OH in tropical forested regions increases by 75-150% relative to ST, reducing the existing model low bias compared to observations. Consequently, isoprene surface mixing ratios decrease considerably (25-40%), significantly improving the model high bias relative to ST. Methane lifetime decreases by 2% and tropospheric ozone burden increases by 4%. Aerosol processes also differ between CRI v2.2 and ST, resulting in changes to the size and number distributions. Relative to ST, CRI v2.2 simulates an 8% decrease in the sulphate aerosol burden with 20% decreases in the nucleation and Aitken modes. By contrast, the secondary organic aerosol (SOA) nucleation mode burden increases by 11%. Globally, the average nucleation and Aitken mode aerosol number concentrations decrease by 20%.The differences in aerosol and gas phase chemistry between CRI v2.2 and ST are likely to have impacts on the radiation budget. We plan to use CRI v2.2 and ST to investigate the influence that the chemical mechanism has on the simulated chemistry-climate feedbacks from BVOCs. In addition, CRI v2.2 will serve as the basis for the addition of a scheme describing the formation of highly oxygenated organic molecules (HOMs) from BVOCs, facilitating a semi-explicit mechanism for new particle formation from organic species.

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Aerosol mass yields of selected biogenic volatile organic compounds – a theoretical study with nearly explicit gas-phase chemistry

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-13741-2019 ◽

2019 ◽

Vol 19 (22) ◽

pp. 13741-13758

Author(s):

Carlton Xavier ◽

Anton Rusanen ◽

Putian Zhou ◽

Chen Dean ◽

Lukas Pichelstorfer ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Gas Phase ◽

Organic Compounds ◽

Chemical Mechanism ◽

Biogenic Volatile Organic Compounds ◽

Gas Phase Chemistry ◽

Mass Load ◽

Volatile Organic ◽

Phase Chemistry ◽

Good Agreement

Abstract. In this study we modeled secondary organic aerosol (SOA) mass loadings from the oxidation (by O3, OH and NO3) of five representative biogenic volatile organic compounds (BVOCs): isoprene, endocyclic bond-containing monoterpenes (α-pinene and limonene), exocyclic double-bond compound (β-pinene) and a sesquiterpene (β-caryophyllene). The simulations were designed to replicate an idealized smog chamber and oxidative flow reactors (OFRs). The Master Chemical Mechanism (MCM) together with the peroxy radical autoxidation mechanism (PRAM) were used to simulate the gas-phase chemistry. The aim of this study was to compare the potency of MCM and MCM + PRAM in predicting SOA formation. SOA yields were in good agreement with experimental values for chamber simulations when MCM + PRAM was applied, while a stand-alone MCM underpredicted the SOA yields. Compared to experimental yields, the OFR simulations using MCM + PRAM yields were in good agreement for BVOCs oxidized by both O3 and OH. On the other hand, a stand-alone MCM underpredicted the SOA mass yields. SOA yields increased with decreasing temperatures and NO concentrations and vice versa. This highlights the limitations posed when using fixed SOA yields in a majority of global and regional models. Few compounds that play a crucial role (>95 % of mass load) in contributing to SOA mass increase (using MCM + PRAM) are identified. The results further emphasized that incorporating PRAM in conjunction with MCM does improve SOA mass yield estimation.

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Analytic solutions for gas-phase chemical mechanism compression

Atmospheric Environment ◽

10.1016/s1352-2310(96)00252-x ◽

1997 ◽

Vol 31 (7) ◽

pp. 1025-1039 ◽

Cited By ~ 8

Author(s):

P.A. Makar ◽

S.M. Polavarapu

Keyword(s):

Gas Phase ◽

Analytic Solutions ◽

Chemical Mechanism ◽

Phase Chemical

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Feasibility Study of Raman Spectroscopy as a Tool to Investigate the Liquid-Phase Chemistry of Aliphatic Organic Peroxides

Applied Spectroscopy ◽

10.1366/0003702971938795 ◽

1997 ◽

Vol 51 (1) ◽

pp. 74-80 ◽

Cited By ~ 8

Author(s):

Peter Jacob ◽

Bernhard Wehling ◽

Wieland Hill ◽

Dieter Klockow

Keyword(s):

Hydrogen Peroxide ◽

Raman Spectroscopy ◽

Liquid Phase ◽

Chemical Processes ◽

Organic Peroxides ◽

Time Resolved ◽

In Situ Investigation ◽

Phase Chemistry ◽

Kinetics Of

The described investigations are focused on peroxides occurring as products in atmospheric chemical processes, namely, hydrogen peroxide, methylhydroperoxide, hydroxymethylhydroperoxide, bis-(hydroxymethyl)peroxide, 1-hydroxyethylhydroperoxide, bis-(hydroxyethyl)peroxide, and hydroxymethylmethylperoxide. The compounds are identified and determined through the position and intensity of their characteristic O–O stretching bands in the range between 767 and 878 cm−1. Time-resolved Raman spectroscopy of peroxide solutions permits the in situ investigation of pathways and kinetics of reactions between peroxides and aldehydes.

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