Utrecht University

The water cycle in the Himalaya is poorly understood because of its extreme topography that results in complex interactions between climate and water stored in snow and glaciers. Hydrological extremes in the greater Himalayas regularly cause great damage, e.g. the Pakistan floods in 2010, while the Himalayas also supply water to over 25% of the global population. So, the stakes are high and an accurate understanding of the Himalayan water cycle is imperative. The discovery of the monumental error on the future of the Himalayan glaciers in the fourth assessment report of the IPCC is exemplary for the scientific misconceptions which are associated to the Himalayan glaciers and its water supplying function. The underlying reason is the huge scale gap that exists between studies for individual glaciers that are not representative of the entire region and hydrological modelling studies that represent the variability in Himalayan climates. In CAT, I will bridge this knowledge gap and explain spatial differences in Himalayan glacio-hydrology at an unprecedented level of detail by combining high-altitude observations, the latest remote sensing technology and state-of-the-art atmospheric and hydrological models. I will generate a high-altitude meteorological observations and will employ drones to monitor glacier dynamics. The data will be used to parameterize key processes in hydro-meteorological models such as cloud resolving mechanisms, glacier dynamics and the ice and snow energy balance. The results will be integrated into atmospheric and glacio-hyrological models for two representative, but contrasting catchments using in combination with the systematic inclusion of the newly developed algorithms. CAT will unambiguously reveal spatial differences in Himalayan glacio-hydrology necessary to project future changes in water availability and extreme events. As such, CAT may provide the scientific base for climate change adaptation policies in this vulnerable region.

Savannas occupy about one-eighth of the land surface worldwide but the vegetation distribution in this biome is not properly understood. Furthermore, land use and climate change are propelling shifts in vegetation characteristics and their spatial distribution. Also, at the savanna-forest boundary, where the two biomes are known to exist as alternative states for same climatic conditions, the importance of spatial heterogeneity has been recognized but not well understood. This project will study how the dynamic interaction of vegetation with its environment leads to spatial organization of vegetation in the savannas including at the savanna-forest transition zone. Motivated by recent findings, it will further explore the significance of these patterned structures in increasing ecosystem resilience and reversing transition of ecosystem states. The research will use multidisciplinary knowledge from ecology and applied mathematics. The fellow, Mr. Swarnendu Banerjee, being from a mathematical background but with experience in ecological modelling has the most appropriate foundations to carry out the proposed research. This project will aptly complement his skills by training him in tropical ecology, spatial modelling and state-of-the-art mathematical methods, which will help him grow as an independent scientist in the field. During this project, he will also develop his transferrable skills in terms of writing and communication, project management, language acquisition and networking. The research that will be carried out will provide fundamental insights into the savanna dynamics potentially opening up novel avenues in savanna conservation research. The results generated from the project will be disseminated to the scientific community via scientific conferences and journal publications. Various means like popular science articles, animated videos and social media platforms will be used to communicate the ideas to the general public.

Dissolved oxygen is an essential substance for a large portion of marine biota. Hypoxia, the reduction of dissolved oxygen concentrations to levels which are detrimental to the health of aerobic organisms, is currently expanding throughout the world's coastal areas, creating a negative impact from both the environmental (e.g. reduced biodiversity, reduced population growth, formation of 'dead zones') and economical (loss of fisheries) perspectives. Through the development and usage of local to global scale biogeochemical models, this research addresses past, present, and future formation of hypoxic 'dead zones' as a result of human-induced nutrient loadings and climate change. These topics are relevant for both industry and society, as they include the effects of changing river nutrient export to coastal marine ecosystems on the increasing frequency, extent, and duration of hypoxia. These studies will serve to further constrain nutrient reduction strategies and their effect on the amelioration of hypoxia in various coastal environments.