The Pinatubo Emulation in Multiple models (PoEMS) experiment
Abstract
The Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP) explores uncertainties in the processes that connect volcanic emission of sulfur gas species and the radiative forcing associated with the resulting enhancement of the stratospheric aerosol layer. The central aim of ISA-MIP is to constrain and improve interactive stratospheric aerosol models and reduce uncertainties in the stratospheric aerosol forcing. This poster focusses on one of four co-ordinated inter-model experiments designed to investigate key processes which influence the formation and temporal development of stratospheric aerosol.
The PoEMS experiment involves interactive stratospheric aerosol models running a perturbed parameter ensemble (PPE) of simulations through the 1991-1995 Pinatubo-perturbed period. Variation-based sensitivity analysis will derive a probability distribution function (PDF) for each model's predicted Pinatubo forcing, following techniques applied successfully to quantify and attribute sources of uncertainty in tropospheric aerosol forcings (e.g. Carslaw et al., 2013). The approach will teach us which aspects of the radiative forcing from major eruptions is most uncertain and will enable us to identify how sensitive model predictions of key features (e.g. timing and value of peak forcing and decay timescales) are to uncertainties in several model parameters. Following the sign-up phase, 12 interactive stratosphere aerosol models are running the ISA-MIP experiments, and aerosol module diversity comprises both microphysical representation (e.g. sectional and modal aerosol dynamics) and extended composition (some models include mixed organic-sulphuric and meteoric-sulphuric particles). The PoEMS experimental design seeks to compare the "uncertainty decomposition" in each model comparing between models with greater sophistication in chemistry and aerosol process, and/or improved resolution of stratospheric circulation/dynamics and exchange with the troposphere. We will show initial results from One-At-A-Time tests in the UM-UKCA model (Dhomse et al. 2014; Brooke et al., 2017; Marshall et al., 2018; 2019)process parameters such as coagulation efficiency, sedimentation rate (as a proxy for growth), and SO2 oxidation rate.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A51R2648L
- Keywords:
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- 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 3362 Stratosphere/troposphere interactions;
- ATMOSPHERIC PROCESSES