David is based in the Climate Research Lab at the School of Geography and the Environment, University of Oxford. His doctoral research focuses on improving scientific understanding about the seasonality of Congo Basin evaporation. He holds an MSc in Applied Meteorology (Distinction) from the University of Reading, where he specialised in climate change, tropical meteorology and environmental data analysis. He also holds a BA in Geography (First Class) from the University of Oxford, where he specialised in physical geography and climate variability.
Alongside his doctoral research, David contributes to the routine observation carried out at the Radcliffe Meteorological Station, which holds the longest single-site set of temperature and rainfall records in the United Kingdom. He undertook a three month summer internship at the Centre for Ecology and Hydrology in Wallingford in 2019, funded by Hydro-JULES. Working within the team responsible for the COSMOS-UK environmental monitoring network, he wrote the code underpinning a new actual evaporation (AET) data system, which is now deriving AET in near real time for 50 COSMOS-UK sites around the UK as a residual of the surface energy balance. He also undertook a three month summer internship at the Met Office in Exeter in 2017. Working in the OSTIA sea surface temperature analysis group, he set up a new night-time only configuration of the OSTIA system, and evaluated the benefits of this system compared to the existing one in a technical report.
Current Research
Evaporation (sometimes referred to as ‘evapotranspiration’) is the transfer of water vapour from the land surface into the atmosphere. Evaporation drives weather patterns, affecting cloud formation, convection and rainfall. In the Congo Basin, evaporation from the tropical rainforest to the north and from the deciduous savannah to the south is believed to provide up to 50% of the moisture that is returned to the surface as rainfall. Understanding the processes responsible for the annual cycle of evaporation is desirable, as these processes are likely to have important consequences for the seasonal differences in rainfall amount and distribution across the basin. However, the processes controlling this seasonality have been understudied, owing to a lack of available observational data from flux towers.
In his DPhil project, David aims to evaluate global climate model, reanalysis and satellite data to determine, in the absence of in situ observations, the most likely set of dynamics which control the seasonality of Congo Basin evaporation. His first publication in Journal of Geophysical Research: Atmospheres examined the credibility of the evaporation produced in the Congo Basin by eleven global climate models. He found that the models which produce evaporation realistically against reliable reference data consistently produce less evaporation at the peak of the second rainy season (November) than the peak of the first (March) on the basin-wide average, because the models release less transpiration from the vegetation. In follow up work, David aims to continue exploring the climatology of Congo Basin evaporation using reanalysis and satellite data, in order to move towards a more complete understanding of why the annual cycle of evaporation behaves as it does.
Publications
Crowhurst, D.M., Dadson, S.J. and Washington, R. (2020) Evaluation of Evaporation Climatology for the Congo Basin Wet Seasons in 11 Global Climate Models. Journal of Geophysical Research: Atmospheres, 125(6). doi: 10.1029/2019JD030619
