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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities
 

Lead Supervisor: Andrew Friend, Geography

Brief summary: 
The global land surface is a poorly understood component of the global carbon cycle - this project will investigate the mechanisms responsible for the observed spatial and temporal variability in global land-atmosphere CO2 exchange using a new terrestrial ecosystem and land use model.
Importance of the area of research concerned: 
The global land surface is a key and highly dynamic component of the global carbon cycle, sequestering c.31% of the combined industrial and land use C emissions over 2010-2019 in natural lands, greatly reducing the atmospheric CO2 accumulation rate and hence climate change. However, global models have poor agreement regarding the contributions of different mechanisms and regions to this uptake, and struggle to reproduce the observed interannual and spatial variability of net fluxes (Canadell et al., 2021). Current understanding, as formulated in these models, therefore limits our ability to quantify future atmospheric CO2 and hence climate, even if we knew anthropogenic emissions. New approaches are therefore required, preferably integrating biologically realistic approaches to physiological and ecological processes, with mechanistic formulations of surface dynamics such as soil water and energy, land use, fire, and permafrost.
Project summary : 
We are constructing a new global model based on novel concepts that promises to resolve at least some of the problems with existing approaches. Our model is formulated from the biological perspective of the plant, with mechanistic approaches to physiological processes and explicit competition between individuals for light, water, and nutrients. There are many possible avenues to explore with the model, and therefore the specific project can be developed around the particular interests of the student. Options include (i) further development of a model component (e.g. competition, fire, permafrost, soil respiration, land use); (ii) a focus on validation (e.g. using remote sensing); or (iii) a regional focus (e.g. Miombo savanna woodland or the subarctic). The model will contribute to annual assessments of the global carbon cycle (https://www.globalcarbonproject.org).
What will the student do?: 
This will depend on the details of the project they choose, but will likely involve further developing and running the global model, comparing its outputs with key validation datasets (e.g. from iLAMB), and writing and presenting results. The model is written in Fortran and runs on the Cambridge parallel computing cluster. Inputs and some outputs use netCDF and there are many tools and datasets for analysing and running the model available.
References - references should provide further reading about the project: 
Canadell, J.G., P. M. S. Monteiro, M. H. Costa, L. Cotrim da Cunha, P. M. Cox, A. V. Eliseev, S. Henson, M. Ishii, S. Jaccard, C. Koven, A. Lohila, P. K. Patra, S. Piao, J. Rogelj, S. Syampungani, S. Zaehle, K. Zickfeld, 2021, Global Carbon and other Biogeochemical Cycles and Feedbacks. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press.
Friend, A.D., Eckes-Shephard, A., Fonti, P., Rademacher, T.T., Rathgeber, C., Richardson, A.D. and Turton, R.H., 2019. On the need to consider wood formation processes in global vegetation models and a suggested approach. Annals of Forest Science, doi:10.1007/s13595-019-0819-x
Friend, A.D., Lucht, W., Rademacher, T.T., Keribin, R., Betts, R., Cadule, P., Ciais, P., Clark, D.B., Dankers, R., Falloon, P.D., Ito, A., Kahana, R., Kleidon, A., Lomas, M.R., Nishina, K., Ostberg, S., Pavlick, R., Peylin, P., Schaphoff, S., Vuichard, N., Warszawski, L., Wiltshire, A. and Woodward, F.I., 2014. Carbon residence time dominates uncertainty in terrestrial vegetation responses to future climate and atmospheric CO2. Proc Natl Acad Sci U S A, v. 111, p.3280-3285. doi:10.1073/pnas.1222477110
Applying
You can find out about applying for this project on the Department of Geography page.
Dr Andrew Friend
Department of Geography Graduate Administrator