Climate and air quality impacts of high latitude vegetation fires

Supervisors: Dr. Steve Arnold(SEE), Prof. Dominick Spracklen(SEE), Dr. Mark Parrington (ECMWF)

The Arctic has warmed rapidly over recent decades, at around twice the rate of global mean temperature increases, resulting in rapid changes to the high latitude Earth system. Changes in the high latitude terrestrial environment include observed increases in temperature extremes and precipitation patterns, which are contributing to positive trends in wildfires. Recent years have seen unprecedented landscape fire activity at Arctic latitudes, leading to the release of substantial quantities of particulate matter and gas-phase pollutants. These emissions lead to unhealthy air quality in high latitude settlements, and have the potential to affect climate through changing the distribution of short-lived climate pollutants (SLCPs), such as particulate matter, tropospheric ozone and methane. The summers of 2019 and 2020 have seen a large increase in the occurrence of fire activity at Arctic latitudes (> 60N) in Russia, releasing quantities of smoke directly into the Arctic atmosphere that are unprecedented over the satellite era. The potential for a climate change-driven long-term shift towards increased fire activity in the Arctic poses urgent questions regarding resultant environmental and societal impacts, and about their context alongside other drivers of Arctic change.

Fig 1: NASA Terra satellite image of fires and smoke across a large area of Siberia on July 21, 2020. c/o nasa.gov

This PhD project will focus on improving understanding of emissions from vegetation fires at high latitudes, and their impacts on atmospheric composition, climate and air quality. The studentship will explore the impacts of changes in the prevalence and distribution of high latitude fires over the past two decades. The project will exploit 18 years of reanalysis data from the Copernicus Atmosphere Monitoring Service (CAMS) system, incorporating emission data from the Global Fire Assimilation System (GFAS). The student will use these datasets to explore linkages between observed high latitude fire activity and emissions, between fire emissions and atmospheric SLCPs, and between fire-driven perturbations to high latitude SLCP distributions and climate forcing. Additional analysis using offline chemical transport model simulations will be used to further probe processes, which the student will run locally on the Leeds ARC4 high performance computing system.

Fig 2: Fire-sourced aerosol optical depth showing extensive smoke plumes from high latitude fires in July 2019, based on output from the Copernicus Atmosphere Monitoring Service (CAMS) forecast. c/o Mark Parrington, ECMWF.

The student will benefit from training in expertise in both numerical atmospheric chemistry-climate modelling and analysis of large geophysical datasets. The student will be involved in analysis of a large suite of  reanalysis model simulations, and there will be the opportunity to design and run their own chemistry transport model experiments on the local ARC4 high performance computing facility. The student will benefit from working with the Centre for Environmental Modelling and Computation (CEMAC) within the School, who can provide expertise and support in running and analyzing model simulations.

Aims and Objectives

The overall aim of the project is to better quantify the role of high latitude fire in affecting atmospheric composition and climate,  and recent changes in these impacts.

The project will address the following research questions:

  • How do uncertainties in emission estimates specifically associated with Siberian fires impact simulated atmospheric composition at high latitudes?
  • How have spatial patterns and seasonality in emissions and smoke transport, and resultant patterns of climate forcing, changed over time over the CAMS reanalysis period (18 years)?
  • How do air qualityimpacts of high latitude fires vary as a function of fire location and timing of emissions, and how have these impacts changed over time?
  • What are competing influences from smoke aerosol and non-CO2trace gases in driving cooling or warming influences (radiative forcings) due to fire emissions at high latitudes? How do the latitude of fire locations and chemical composition of emissions affect the efficacy of these forcings?
  • Is there evidence for a potential fire / climate feedback at high latitudes, driven by emissions from fires and resultant climate response?

Research Group and Collaborations

The student will join a group of around 10 students and postdoctoral researchers working on projects in atmospheric composition and its links to climate, air quality and the biosphere. For more information about our research and recent publications, see: https://environment.leeds.ac.uk/see/staff/1135/dr-steve-arnold. We encourage interested applicants to get in touch and arrange an informal visit to Leeds to meet and talk informally with the group.

The student will collaborate closely with the CAMS team at ECMWF, and will partake in regular meetings and scientific community events with ECMWF staff, and will have the opportunity to make regular research visits to ECMWF. The project will be closely aligned to the ACRoBEAR(Arctic Community Resilience to Boreal Environmental change: Assessing Risks from fire and disease) project, which aims to predict and understand health risks from and societal resilience to wildfire air pollution and natural-focal disease at high latitudes. The student will be integrated within the ACRoBEAR research and stakeholder communities, and will benefit from engagement with a broad interdisciplinary and international project team. In particular, it is expected that the student will collaborate closely with the ACRoBEAR modelling team, involved in regional air quality simulations and fire emission modelling for the pan-Arctic region.