Investigation of the transport and fate of biomass burning aerosol particles in the global climate model HadGEM3-UKCA

Institution: University of Exeter

Lead Supervisor: Dr Daniel Partridge

Project Description

Reducing current uncertainty surrounding climate change projectionsis contingent on improving representation of small-scale cloud processes in global climate models (GCMs), in particular, the complex interactions between clouds and aerosols.One staple approach used to investigate aerosol sources/sinks in the atmosphere is the calculation of air-mass trajectories arriving at measurement stations using re-analysed fields from numerical weather prediction models.

This placement would constitute an independent component of an ongoing globaltrajectory-based assessment of aerosols in the Met Office GCM HadGEM3-UKCA. The student will focus onAscension Island (ASI) station, the location of theCLARIFY campaign. CLARIFY aims to improve current understanding of the transport, fate, and climate impact of biomass burning aerosols (BBA). First, an analysis of trajectories will be performed to trace transport patternsin HadGEM3-UKCAand determine when and how BBA are entrained into the south east Atlantic marine boundary layer. The student will investigate atmospheric sources and sinks processes controlling BBA along the trajectories to identify atmospheric signals for forecasting BBA plumes.

Subsequently the placement involvesparticipation during CLARIFY (funding is available to cover additional costs) toset model analysis in the context of real world observations.The student will assist the forecast process at ASI by liaising between the permanent Met Office, ARM Mobile Facility (AMF), and operations office. Lidar data from the AMF combined with forecast products and experience gained from trajectory analysis will aidputting the aircraft in the right place at the right time.

The work would take place under my direct supervision and s/he will benefit from interaction with Prof. Haywood (CLARIFY PI),and the UK Met Office. The student would gain experience via training in analysing and processing big data using Matlab, interpretation of model output, and practical experience in forecasting for the optimum deployment of aircraft for atmospheric research.

Indicative timescale for project (subject to change)

The student will perform analysis of pre-existing trajectories from HadGEM3-UKCA calculated for the ASI AMF measurement station during 2006-2016 to identify transport patterns of BBA during the first three weeks of the placement (July 3rd – July 14th). To prepare for contribution during the CLARIFY campaign the student will participate in a planned dry run for BBA plume forecastingat the UK Met Office July 17th – 21st using tools available in-situ at ASI.The following three weeks (July 24th – August 14th) will be spent investigating factors affecting climate modelsimulation of BBA using trajectory analysis. Statistical techniques will be demonstrated to the student to facilitate identification of key atmospheric processes controlling the presence of BBA in the south east Atlantic. The remaining placement time (August 15th – September 8th) will be split between participation at ASI for CLARIFY followed by final analysis of model data informed by first assessment of measurement data.

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