Job Description

Would you like to help to address some of the biggest uncertainties in climate projections, do you have an established background in clouds and aerosol research and do you want to further your career in a one of the world’s leading atmospheric science institutes? 

You will become a key team member of the Ice Nucleation group in Leeds who are playing a leading role in NERC’s CloudSense programme (https://cloudsense.ac.uk/). You will be responsible for making measurements of ice-nucleating particles in two international field projects within the CloudSense programme: DCMEX: (Deep convective microphysics experiment) and M-Phase (Resolving climate sensitivity associated with shallow mixed phase cloud in the oceanic mid- to high-latitudes. In both of these projects you will make use of the newly developed Portable Ice Nucleation Experiment (PINE) instrument which is a new instrument for semi-autonomously measuring the concentration of atmospheric INP.

Resolving climate sensitivity associated with shallow mixed phase cloud in the oceanic mid- to high-latitudes (M-Phase)

Shallow mixed phase clouds are a critical, but poorly understood part of the climate system (Murray et al. 2021). M-Phase aims to address this deficit through a combination of lab, field and modelling work. It is a major £3 Million project funded by NERC with multiple partners including the University of Manchester and the UK Met Office. The overarching objective of M-Phase is to reduce the uncertainty in how mixed-phase clouds will respond to changes in climate, and thereby reduce uncertainty in climate sensitivity. We will do this by improving our understanding of the physical processes that determine the properties of mixed-phase clouds and their response to climate drivers (sea-surface temperatures and aerosols). M-Phase will include ship and aircraft campaigns in the region of the Labrador Sea.

M-Phase builds on a previous work where we demonstrated that shallow clouds are extremely sensitive to INP concentrations (Vergara-Temprado et al., 2018), with high INP leading to low amounts of supercooled water and lower albedo. In a warmer future world, these clouds will contain less ice and will therefore be more reflective, which represents a strong negative climate feedback (Storelvmo et al. 2015). It has been shown that improving the representation of ice in clouds increases the equilibrium climate sensitivity (the amount the planet will warm with a doubling of CO₂) by 2 K (Tan et al., 2016). Hence, the present day INP concentration directly impacts the extent to which our planet will warm and the work you will do within M-Phase will therefore be critically important.

Deep convective microphysics experiment (DCMEX)

The microphysical processes, including ice nucleation, in deep convective clouds play a key role in defining their properties and role in cloud climate feedbacks. For example recent modelling in Leeds clearly demonstrates that the amount and temperature dependence of ice-nucleating particles defines the properties of the anvil cirrus cloud (Hawker et al. 2021). DCMEX is focused on measurements of cloud microphysics in real-world laboratory type cumulonimbus clouds that form on an almost daily basis above the Magdelana mountains in New Mexico. Because it is a predictable cloud, it is an ideal t case for making measurements aimed at improving the representation of cumulonimbus clouds in global climate models around the world. The FAAM aircraft will be deployed with state-of-the-art aerosol and cloud physics instruments, along with remote sensing and ground based measurements.

The common uncertain link

Core to both DCMEX and M-Phase are the measurements of the number concentration of ice-nucleating particles (INPs) that become active as a function of temperature. In the absence of INPs cloud droplets can supercool to well below -35°C and the prediction of primary ice crystals on INPs can trigger a cascade of microphysical properties which can completely alter the properties of a cloud and even interact with dynamics. In this position you will make measurements of INP in two distinct ways. Firstly, you will collect aerosol onto filters from the FAAM aircraft and use cold stage assays to quantify the INP spectra (e.g. Sanchez-Marroquin et al., 2020). Alongside this you will make use of electron microscopy to examine the size resolved aerosol composition.

The second technique you will use is for long term monitoring of INP using the new PINE chamber (Möhler et al. 2021). This instrument was developed in a collaboration between Leeds-KIT (Karlsruhe Institute of Technology) and offers an unprecedented level of automation. We intend to get use it for long term measurements from the Langmuir lab for the entire 2023 summer season (in the Magdelena Mountains). Finally, you will be responsible for overseeing ground based measurements of INP at the Langmuir lab during the FAAM flights in 2022.

Your primary role will be as the DCMEX postdoc who is responsible for the INP measurements (on FAAM in July-August 2022, at the Langmuir lab in July-August 2022 and at the Langmuir Lab over summer 2023). You will also assist the M-Phase INP postdoc (Dr Mark Tarn) in the FAAM flights (Oct 2022 in the Labrador Sea region) and to prepare the PINE chamber and inlet system for the M-Phase cruise (May 2022). The involvement in M-Phase will not only be invaluable support for the project, but will also offer an excellent opportunity to learn how to make the necessary measurements.

An important part of your job will be to interact with the CloudSense modellers in order that we make the most useful measurements possible and also to ensure that the results are used correctly.

In Leeds we have a long history of modellers and experimentalists working together and this has resulted in a number of major influential publications where new physical insights have been used to define processes on a global scale leading to first order discoveries.

To explore the post further or for any queries you may have, please contact: 

Ben Murray, Professor of Atmospheric Science (lead on M-Phase)

Email: [email protected] 

Alan Blyth, Professor of Atmospheric Science (lead on DCMEX)

Email: [email protected]