The role of meltwater in reshaping the structures of icy porous media
Icy porous materials such as snow or firn are ubiquitous in both Earth and planetary settings. Their microstructures (e.g., porosity) play an important role in dictating the reflectivity, fluid storage capacity, thermal conductivity, and mechanical properties of the larger-scale systems. Thus, understanding the complex physics that control the microstructure evolution of icy porous media is an important component in creating robust predictions of Earth’s cryosphere in response to climate warming, and in...
Earth’s mantle has been oxidized compared to its cosmochemical building blocks since the earliest Hadean. This oxidation is linked to Earth’s initial differentiation, including processes in magma oceans, but these remain poorly understood. During its subsequent evolution to the present, Earth has developed a substantial oxidized surface reservoir that amounts to approximately 20% of the oxidative power of the accessible Earth, with the other 80% remaining in the mantle. This surface reservoir is essential to the modern surface environment, but...
Hurricanes are a major disturbance to tropical forests. We used census observations at Bisley Experimental Watersheds (BEW) in Puerto Rico to study the mortality after hurricane Hugo in 1989 and after hurricane Maria in 2017 and the subsequent recovery of the forest after hurricane Hugo between 1989 and 2014 (the last census before hurricane Maria). We found that hurricane-induced mortality varied with species/plant functional types (PFTs) and stem sizes. Specifically, palms had the lowest mortality, followed by mid and late...
Earthquake Insights From the Best Recorded Volcanic Caldera Collapse In History
Two outstanding problems in seismology are predicting the recurrence times of earthquakes and understanding the physical processes that immediately precede them. While geodetic measurements record elastic strain accumulation, most faults have recurrence intervals far longer than available measurements. Foreshocks provide the principal observations of processes prior to mainshocks, yet variability between sequences has limited generalizations of pre-failure behavior. In 2018 Kilauea volcano...
Surface Evaporation and Rainfall Partitioning in Arid Lands - Local and global perspectives
The presentation will explore two interconnected vignettes related to surface evaporation. In the first part we will review basic aspects of surface evaporation and discuss how soil type modulates evaporation dynamics via surface resistance and internal drainage that shelter infiltrated rainwater from evaporation losses (but not from plant water uptake). These basic elements offer a simple pathway for estimation of surface evaporation losses locally and globally. In the second part,...
Talk Title: Raising our expectations for DEI work in geoscience faculty evaluation systems: an insight into who sustains this work and how this labor is recognized and rewarded
Abstract: The geosciences have an ethical obligation to increase the low racial and...
Talk Title: Advances in Global Hydrology based on GRACE Satellite Gravimetry
Abstract: Two decades of GRACE (Gravity Recovery and Climate Experiment) satellite data have significantly advanced our understanding of global hydrology. GRACE satellites measure variations in Earth’s gravity which are controlled mostly by water storage changes, such as those related to...
Abstract: Abstract: Now more than ever we need to understand how peatlands are formed, how they thrive, and how they can be maintained to control CO2 emissions. I will describe results from a unique field program in Borneo designed to study the coupled ecological and hydrological processes that operate in tropical peatlands. We show how tropical peatlands exist because of a positive feedback between peat accumulation and water table rise. Organic material from tropical rain forests accumulates over millennia in...
Abstract: Abstract: Now more than ever we need to understand how peatlands are formed, how they thrive, and how they can be maintained to control CO2 emissions. I will describe results from a unique field program in Borneo designed to study the coupled ecological and hydrological processes that operate in tropical peatlands. We show how tropical...
Talk Title: Reconstructions of Cenozoic atmospheric CO2 and ocean carbon cycle perturbations
Abstract: My research interests focus on understanding the role of the ocean, and in particular the role of marine carbonate chemistry in global climate change. As I was originally trained as a (marine) biologist, my way of approaching paleoceanographic questions often...
Talk Title: Climatic effects of local land cover and land use change
Abstract:
Land cover on the Earth’s surface typically varies at spatial scales smaller than the grid size of a climate model. Similarly, contemporary land use activities, such as urbanization and deforestation, are occurring at local scales than cannot be resolved by climate models. Heterogeneity in land cover causes spatial variability in...
Talk Title: Carbon-Water cycle interactions from a measurement and modeling perspective
Abstract: Stomata act as the gate-keeper of carbon uptake and transpiration water losses and can control regional-scale fluxes. Recent studies have found that soil moisture variations are a dominant driver for inter-annual variations in the atmospheric CO2 growth rate, both...
Talk Title: Lessons Learned about the Breathing of the Biosphere, from a Californian Network of Greenhouse Gas Flux Measurement Towers
Abstract: This talk will revolve around lessons learned by collecting quasi-continuous and long term trace gas fluxes from a network of managed and natural fields sites across California. We will investigate if and how fluxes are...
Talk Title: Modeling Extreme Events and Their Future Changes
Abstract: Some of the most consequential outcomes of global warming for societies and ecosystems are changes in extreme events. Comparing 2000-2019 with 1980-1999, extreme temperature and flood events have more than doubled globally while the number of disastrous storms and droughts has increased by 30-50%. While the nonlinear increase in latent energy with warmer surface air temperature may explain the global increasing trends in weather...
Talk Title: Witnessing the Assembly of Planetary Systems
Abstract: We have observed a stunning diversity in the properties of exoplanetary systems which questions our understanding of planet formation. Does this diversity arise from differences in initial conditions? Are there multiple modes of planet formation which preferentially build different types of planets? Or does this diversity stem from the evolution of the newly born planetary system as the natal protoplanetary disk dissipates? Over the last several years we have gained an incredible...
