Vegetation dielectric constant as a measure of water stress

Research interest

Microwave emission and backscatter of vegetated surfaces are influenced by the dielectric constant of vegetation, which is a function of vegetation water content. The variation in vegetation water content is highly depending on the available moisture in the root zone. Understanding the effect of changing root zone water availability on the vegetation dielectric constant could therefore improve soil moisture retrieval using microwaves above vegetated areas.

In the years to come, my research will focus on understanding the effects of water stress on vegetation water content, vegetation dielectric constant and emission/backscatter of microwaves. How? Spend many a day modeling changing dielectric properties of maize plants, and measuring water stressed leaves in the field!


Tim started his Ph.D. in July 2013. Before, he finished both his B.Sc. and M.Sc. in Civil Engineering at Delft University of Technology. For his BSc thesis, Tim investigated how the design of small scale irrigation systems could improve agricultural activities in Kilole, Kenya. This included a month long fieldwork campaign. From August 2012 to March 2013, Tim worked on his MSc thesis: “Diurnal differences in vegetation dielectric constant as a measure of water stress”.

Over the years, Tim worked on various projects, covering many fields of hydrology and water resources management. In the fall of 2011, he designed a new method to measure the temperature in the upper layer of lakes using Distributed Temperature Sensing, which was successfully tested in Israel and Ghana. During the spring of 2012, Tim spent three months in an ungauged basin in Cambodia, to develop an approach to quantify annual water availability, to be used for agriculture. From April to July 2013, Tim was a visiting scientist at the University of Illinois at Urbana-Champaign, where he made the first steps in developing a distributed socio-hydrologic model.

In 2012, Tim was the co-founder of the Young Hydrologic Society, an organization to connect young hydrologists all over the world and thereby stimulating scientific collaboration. 

Besides water resources and hydrology, Tim is very passionate about traveling in strange places, CouchSurfing, learning languages, Italian cuisine, slow food, and thinking about ways to make this world a better place.

WRM Issues

Relevant Tools