A5029440292- Climate change and permafrost
- Atmospheric and Environmental Gas Dynamics
- Cryospheric studies and observations
- Marine and coastal ecosystems
- Arctic and Antarctic ice dynamics
- Water Quality and Pollution Assessment
- Methane Hydrates and Related Phenomena
- Soil and Water Nutrient Dynamics
- Indigenous Studies and Ecology
- Fish Ecology and Management Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Geochemistry and Geologic Mapping
- Water Quality Monitoring and Analysis
- Mercury impact and mitigation studies
- Remote-Sensing Image Classification
- Coastal and Marine Management
- Water Treatment and Disinfection
- Aquatic and Environmental Studies
- Geological Studies and Exploration
- Polar Research and Ecology
- Freezing and Crystallization Processes
- Landslides and related hazards
- Arctic and Russian Policy Studies
- Groundwater and Isotope Geochemistry
- Hydrology and Watershed Management Studies
University of Virginia
2020-2022
University of Minnesota
2017-2020
The University of Texas at Austin
2011-2017
Clark University
2011
Abstract Northern rivers connect a land area of approximately 20.5 million km 2 to the Arctic Ocean and surrounding seas. These account for ~10% global river discharge transport massive quantities dissolved particulate materials that reflect watershed sources impact biogeochemical cycling in ocean. In this paper, multiyear data sets from coordinated sampling program are used characterize organic carbon (POC) nitrogen (PN) export six largest within pan‐Arctic (Yenisey, Lena, Ob', Mackenzie,...
[1] The Kolyma River basin in northeastern Siberia, the sixth largest river draining to Arctic Ocean, contains vast reserves of carbon Pleistocene-aged permafrost soils. Permafrost degradation, as a result climate change, may cause shifts riverine biogeochemistry this old source organic matter is exposed. Satellite remote sensing offers an opportunity complement and extrapolate field sampling dissolved expansive region. We develop empirically based algorithms that estimate chromophoric...
Abstract Secchi depth (SD), a primary metric to assess trophic state, is controlled in many lakes by algal densities, measured as chlorophyll‐ (chl‐ ) concentration. Two other optically related water quality variables also directly affect SD : non‐algal suspended solids ( SS NA and colored dissolved organic matter CDOM , expressed the absorption coefficient at 440 nm, ). Using database of ~1,460 samples from ~625 inland lake basins Minnesota two Upper Midwest states, Wisconsin Michigan, we...
Abstract Across the globe, recent work examining state of freshwater resources paints an increasingly dire picture degraded water quality. However, much this either focuses on a small subset large waterbodies or uses in situ quality datasets that contain biases when and where sampling occurred. Using these unrepresentative samples limits our understanding landscape level changes aquatic systems. In lakes, overall clarity provides strong proxy for because it responds to surrounding...
Deep learning (DL) convolutional neural networks (CNNs) have been rapidly adapted in very high spatial resolution (VHSR) satellite image analysis. DLCNN-based computer visions (CV) applications primarily aim for everyday object detection from standard red, green, blue (RGB) imagery, while earth science remote sensing focus on geo and classification multispectral (MS) imagery. MS imagery includes RGB narrow spectral channels near- and/or middle-infrared regions of reflectance spectra. The...
Very high spatial resolution commercial satellite imagery can inform observation, mapping, and documentation of micro-topographic transitions across large tundra regions. The bridging fine-scale field studies with pan-Arctic system assessments has until now been constrained by a lack overlap in geographical coverage. This likely introduced biases climate impacts on, feedback from the Arctic region to global system. central objective this exploratory study is develop an object-based image...
Assessing permafrost-release signals in arctic rivers is challenging due to mixing of complex carbon components contrasting ages. Compound-specific 14C analysis terrestrially derived molecules may reduce the influence mixed sources and potentially provide a closer examination on dynamics permafrost-derived rivers. Here we employed recently modified method determine radiocarbon contents lignin phenols, as classic tracer for terrestrial carbon, isolated from dissolved organic matter (DOM) two...
Abstract This article presents a framework for integrating regional geographic information system ( GIS )‐based nitrogen dataset (Texas Anthropogenic Nitrogen Dataset, TX ‐ ANB ) and ‐based river routing model (Routing Application Parallel computation of Discharge) to simulate steady‐state riverine total TN transport in networks containing thousands reaches. A two‐year case study was conducted the San Antonio Guadalupe basins during dry wet years (2008 2009, respectively). investigates...
Colored dissolved organic matter (CDOM), a major component of the carbon (DOC) pool in many lakes, is an important controlling factor lake ecosystem functioning. Absorption coefficients at 440 nm (a440, m-1), common measure CDOM, exhibited strong associations with iron (Fediss) and DOC 280 lakes Upper Great Lakes States (UGLS: Minnesota, Wisconsin, Michigan), as has been found Scandinavia elsewhere. Linear regressions between three variables on UGLS data typically yielded R2 values 0.6-0.9,...