Research

My research broadly focuses on studying how ecosystems are adapting and changing in response to climate. This covers a broad range of topics, from long-term landscape evolution to seasonal-scale discharge variability to the resilience of vegetated ecosystems.

Quantifying the Stability of Global Ecosystems

I am interested in the stability of natural systems from a dynamical systems perspective, particularly within the framework of critical slowing down. I have worked extensively on mapping global vegetation resilience, and looked in detail at how to account for multi-satellite data and other data issues in assessments of global vegetation resilience. Much of my current work on dynamical systems approaches focuses on how to deal with seasonality or other non-stationary signals within environmental time series. To this end, I’ve developed new, eigenvalue-based and regression-based methods which can handle non-stationary time series. These methods can also motivate spatially-aware early-warning signals for oncoming ecosystem changes, and extend the study of critical slowing down to new systems, such as predicting mountain glacier surges.

Understanding Changes in Alpine Hydrology

I am currently running my own DFG-funded project which builds upon much of my previous work, particularly that which focused on monitoring snow. The “Quantifying the Influence of Snowmelt on River Hydrology in High Mountain Asia (STRIVE)” project focuses on mapping where, when, and how water enters river systems in Nepal. This work uses a combination of GNSS Reflectometry, satellite data, and in-situ river monitoring. Here is an example time lapse from one of my river monitoring stations, showing the rise and fall of the water throughout the year:

More detailed instructions on how to construct the environmental sensors I design and deploy can be found here: https://github.com/UP-RS-ESP/LowCostSensors.

In the context of this work, I am also interested in changing discharge variability and its link to climatic and land cover changes. Of particular interest is how sediment budgets are responding to increases in precipitation variability throughout High Mountain Asia.

Snow-Water Storage in High Mountain Asia

I have several ongoing research projects based on high-resolution passive microwave data for High Mountain Asia with the goal of producing updated estimates of snow depth and changes in the cyrosphere over the past ~30 years, both following on previous methodologies and developing new ones based on novel clustering techniques for dealing with high-dimensional topographic and climatic data. I am also interested in how these changes link to regional climate, and how snow-water changes propagate downstream into alpine rivers.