Dr Ruth Geen
Telephone: 01392 723612
Extension: (Streatham) 3612
My research aims to increase confidence in projections of future regional climate by building simple, conceptual pictures of the large-scale atmospheric dynamics governing climate phenomena.
In April 2021 I joined James Screen’s team investigating the various pathways by which warming of the Arctic has been suggested to influence European climate and extreme weather. We are using Exeter’s idealised climate modelling framework Isca to pick apart these different proposed mechanisms and identify if and how the Arctic plays a role in European climate.
- Dynamics of East Asian Monsoon Variability and Change (CSSP China)
State-of-the-art climate models show a variety of rainfall biases in the seasonality of the East Asian Summer Monsoon. Troublingly, in many cases these are similar or greater in size than the future rainfall changes the model predicts. Working with Hugo Lambert and Geoff Vallis, I am using simple understanding built up from idealised models to break down processes causing these biases and to try to improve our confidence in future change.
- Latent heat feedbacks onto climate
Before coming to Exeter, I studied for my PhD in the Space and Atmospheric Physics group at Imperial College London, supervised by Arnaud Czaja and Joanna Haigh. My work there investigated the effects of latent heat release by water vapour on the climate system in aquaplanet models, in particular the effects on heat transport by midlatitude storms. My PhD thesis can be found here.
- Simple radiation scheme
As part of my PhD work, I developed a simple three band radiation scheme for the MITgcm. This accounts for water vapour and carbon dioxide, and separates the spectrum into shortwave, longwave window, and longwave non-window components, providing a more realistic alternative to using fixed optical depths, while still being fast to run. During a visit to MIT, working with John Marshall, in November 2015 I helped to incorporate this into the model source code repository, and it is available here. An adapted version of this scheme is also available in Isca.
- Mutton, H., Collins, M., Lambert, H. F., Chadwick, R., Geen, R. and Todd, A., 2021, The Impact of the Direct Radiative Effect of Increased CO2 on the West African Monsoon. Journal of Climate, submitted.
- Scaife, A. A., Hermanson, L., van Niekerk, A., Baldwin, M. P., Belcher, S., Bett, P., Comer, R. E., Dunstone, N. J., Geen, R., Hardiman, S., Ineson, S., Knight, J., Nie, Y., Ren, H.-L. and Smith, D., 2021: Long Range Predictability of the Length of Day and Extratropical Climate. Nature Geoscience. - Under revision.
- Ruth Geen, F. H. Lambert and G. K. Vallis, 2021: The Asian Monsoons as a Unified System. Geophysical Research Letters. - Under revision.
- Xu, P., Wang, L., Vallis, G. K., Geen, R., Screen, J., Wu, P., Ding, S., Huang, P. and Chen, W., 2021: Amplified waveguide teleconnections along the polar front jet favor regional temperature extremes over Northern Eurasia. Geophysical Research Letters, e2021GL093735.
- Ruth Geen, 2021: Forecasting South China Sea Monsoon Onset Using Insight from Theory. Geophysical Research Letters, 48 e2020GL091444.
- Ruth Geen, S. Bordoni, D. S. Battisti and K. L. Hui, 2020: Monsoons, ITCZs and the Concept of the Global Monsoon. Reviews of Geophysics, 58, e2020RG000700.
- Ruth Geen, F. H. Lambert and G. K. Vallis, 2019: Processes and Timescales in Onset and Withdrawal of 'Aquaplanet Monsoons'. J. Atmos. Sci., 76:2357-2373
- Ruth Geen, F. H. Lambert and G. K. Vallis, 2018: Regime change behaviour during Asian monsoon onset. J. Clim., 31:3327-3348
- Geoffrey K. Vallis, Greg Colyer, Ruth Geen, Ed Gerber, Martin Jucker, Penelope Maher, Alex Paterson, Marianne Pietschnig, James Penn, and Stephen Thomson, 2018: Isca, v.1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity. Geosci. Model Dev., 11:843-859
- Gabriele Messori, Ruth Geen and Arnaud Czaja, 2017: On the spatial and temporal variability of atmospheric heat transport in a hierarchy of models. J. Atmos. Sci., 74:2163-2189
- Ruth Geen, Arnaud Czaja and Joanna D. Haigh, 2016: The effects of increasing humidity on heat transport by extratropical waves. Geophysical Research Letters, 43:8314-8321