2025-L15 Geostationary monitoring of aerosols to further numerical weather prediction

Project highlights

Working with the Met Office to improve weather forecasts by creating next-generation satellite observations that track aerosols and clouds throughout the day

Joining an international team of satellite retrieval experts working with the European Space Agency and Copernicus Climate Change Service

Reducing a major source of uncertainty in climate forecasts by constraining the interactions between aerosols, clouds, radiation, and precipitation

Overview

Aerosols are particles or droplets suspended in the air for hours to weeks. They are often thought of as grains of pollen or sand (known as desert dust), though soot and droplets of acid are more numerous. Weather forecasting centres ingest observations of aerosol optical depth (AOD) from satellites to account for the impact of desert dust on weather and climate. These currently provide only one or two snapshots of the desert dust region per day, presenting a need for accurate, continuous measurements to improve predictions of plume evolution.

Aerosols alter weather directly by changing the atmosphere’s temperature profile through the scattering and absorption of sunlight. As the seeds of cloud droplet formation, aerosols can change the properties of clouds and, thus, indirectly affect the Earth’s energy budget. Near the surface, excess exposure to aerosols is detrimental to health, with poor air quality associated with millions of premature deaths every year.

Dust plumes evolve over hours but can extend over thousands of kilometres. Currently, only AOD data from NASA’s MODIS sensors are assimilated into the Met Office (MO) numerical weather prediction (NWP) model. Geostationary sensors collect imagery every 10-15 minutes, providing the continuous coverage needed, particularly after the Meteosat Third Generation satellites become operational. However, their data lacks the accuracy and uncertainty characterisation needed for assimilation, motivating the need for next-generation aerosol products.

This project will adapt the Optimal Retrieval of Aerosol and Cloud (ORAC) to provide the MO with operational aerosol measurements from geostationary sensors. ORAC is an internationally respected algorithm that provides aerosol and cloud climate data records to the European Space Agency and Copernicus Climate Change Service. Applicants should have a background in a quantitative physical science like physics, mathematics, or physical geography.

Figure 1: A plume of Saharan dust blown over western Europe on 15 Mar 2022 that resulted in sepia-toned skies across western Europe. This project will analyse similar images to determine dust properties such as the plume’s height and the size of the particles. Image by Joshua Stevens, using VIIRS data, for the NASA Earth Observatory at https://earthobservatory.nasa.gov/images/149588/an-atmospheric-river-of-dust.

CENTA Flagship

This is a CENTA Flagship Project

Case funding

This project is suitable for CASE funding

Host

University of Leicester

Theme

Climate and Environmental Sustainability

Supervisors

Project investigator

Adam Povey, University of Leicester, [email protected]

Co-investigators

Paul Monks, University of Leicester, [email protected]
Bob Tubbs, Met Office, [email protected]

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
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Methodology

The student will be given access to the MO’s research servers in order to deploy and test ORAC, comparing it to the current MO dust product over ocean. Informed by those results, the student will implement and evaluate various representations of how light scatters off the Earth’s surface to enable accurate measurements over land using geostationary imagery. They will determine how to use new observation modes to identify dust plumes, and determine their height, before optimising the code to achieve the MO’s operational requirements. The resulting aerosol products will be trialled within the forecast’s assimilation scheme, towards delivery of a new dust product by the end of the project. There are many areas for scientific exploration, depending on the interests of the student, such as the influence of desert dust on ice formation within anvil clouds or the role of dust in fertilising the central Pacific with iron.

Training and skills

DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.

Statistical analysis of climatological data will underpin the scientific studies. The student will use and modify ORAC codes, learning the methods of scientific programming in Python and Fortran through CENTA courses, alongside optimisation methods and radiative transfer at Leicester. Field work to collect additional ground observations, potentially at the Chilbolton Observatory, can be supported by the Field Spectroscopy Facility. Presentation and communication skills are taught at the Doctoral College and there will be opportunities to apply them at meetings of the ORAC team and NCEO research themes, as well as international conferences.

Partners and collaboration

The Met Office is the UK’s national weather and climate service, based in Exeter. Dr Tubbs leads the Satellite Imagery group, which develops derived products for situational awareness and nowcasting such as identifying convective systems, estimating cloud properties, and tracking mineral dust or volcanic ash. The MO will provide access to their cloud computing facilities and near-real time data so the student can demonstrate their aerosol products on the operational systems.

Further details

For any enquiries related to this project please contact Adam Povey, University of Leicester, [email protected]. 

Dr Povey’s personal website: https://le.ac.uk/people/adam-povey
Prof Monks’ university website: https://le.ac.uk/people/paul-monks
Earth Observation Science at Leicester: https://le.ac.uk/physics/research/earth-observation-science

The ORAC code base can be accessed at https://github.com/ORAC-CC/orac

To apply to this project: 

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2025.

You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.

Please submit your application and complete the host institution application process via: CENTA PhD Studentships | Postgraduate research | University of Leicester.  Please scroll to the bottom of the page and click on the “Apply Now” button.  The “How to apply” tab at the bottom of the page gives instructions on how to submit your completed CENTA Studentship Application Form 2025, your CV and your other supporting documents to your University of Leicester application. Please quote CENTA 2025-L15 when completing the application form.

Applications must be submitted by 23:59 GMT on Wednesday 8th January 2025. 

Possible timeline

Year 1

Deploy ORAC on MO servers for over-ocean retrievals; Evaluate data against MO, ESA, and NASA dust products; Investigate influence of seasonal cycles on mineralogy.

Year 2

Implement alternative surface reflectance scheme to permit retrievals over land; Quantify influence of dust on ice cloud properties; Assess impact of dust product on forecasts.

Year 3

Estimate flux of iron into tropical oceans; Update representation of dust within radiative transfer code; Optimise ORAC for MO operational systems to deliver a geostationary dust product.