John Wesley Powell Center for Analysis and Synthesis

All Working Groups

Filter Total Items: 65
Date published: October 28, 2013
Status: Active

Exploiting high-resolution topography for advancing the understanding of mass and energy transfer across landscapes: Opportunities, challenges, and needs

One of the grand challenges of Earth Surface Science and Natural Resource Management lies in the prediction of mass and energy transfer for large watersheds and landscapes. High resolution topography (lidar) datasets show potential to significantly advance our understanding of hydrologic and geomorphic processes controlling mass and energy transfer because they represent features at the...

Date published: October 25, 2013
Status: Active

Dam removal: synthesis of ecological and physical responses

Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular,...

Date published: October 25, 2013
Status: Active

Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models

Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines...

Date published: October 25, 2013
Status: Active

Broader view of North American climate over the past two millennia: Synthesizing paleoclimate records from diverse archives

Regional- to continental-scale paleoclimate syntheses of temperature and hydroclimate in North America are essential for understanding long-term spatiotemporal variability in climate, and for properly assessing risk on decadal and longer timescales. However, existing syntheses rely almost exclusively on tree-ring records, which are known to underestimate low-frequency variability and rarely...

Date published: October 22, 2013
Status: Active

Forecasting forest response to N deposition: integrating data from individual plant responses to soil chemistry with a continental-scale gradient analysis

Nitrogen deposition is altering forest dynamics, terrestrial carbon storage, and biodiversity. However, our ability to forecast how different tree species will respond to N deposition, especially key response thresholds, is limited by a lack of synthesis across spatial scales and research approaches. To develop our best understanding of N deposition impact on tree growth and survival, we will...

Date published: October 22, 2013
Status: Active

Water availability for ungauged rivers: an integrative, multi-model approach to estimate water availability at ungauged rivers across the United States

There has been increasing attention placed on the need for water availability information at ungauged locations, particularly related to balancing human and ecological needs for water. Critical to assessing water availability is the necessity for daily streamflow time series; however, most of the rivers in the United States are ungauged. This proposal leverages over $1M currently allocated to...

Date published: October 22, 2013
Status: Active

Integrating modeling and empirical approaches to improve predictions of tropical forest responses to global warming

Tropical forests contain > 50% of the world’s known species (Heywood 1995), 55% of global forest biomass (Pan et al. 2011), and exchange more carbon (C), water and energy with the atmosphere than any other ecosystem type (e.g., Saugier et al. 2001). Despite their importance, there is more uncertainty associated with predictions of how tropical forests will respond to warming than for any...

Date published: October 22, 2013
Status: Active

Potential Impacts of Prospective Climate Change on Groundwater Recharge in the Western United States

Groundwater withdrawals in the western US are a critical component of the water resources strategy for the region. Climate change already may be substantially altering recharge into groundwater systems; however, the quantity and direction (increase or decrease) of changes are relatively unknown as most climate change assessments have focused on surface water systems. We propose to conduct a...

Date published: October 22, 2013
Status: Active

Advancing understanding of ecosystem responses to climate change with warming experiments: what we have learned and what is unknown?

Advancing our mechanistic understanding of ecosystem responses to climate change is critical to improve ecological theories, develop predictive models to simulate ecosystem processes, and inform sound policies to manage ecosystems and human activities. Manipulation of temperature in the field, or the “ecosystem warming experiment,” has proved to be a powerful tool to understand ecosystem...

Date published: October 21, 2013
Status: Active

Joint USGS - GEM Group on Global Probabilistic Modeling of Earthquake Recurrence Rates and Maximum Magnitudes

Despite the best monitoring networks, the highest rate of earthquakes and the longest continuous recorded history in the world, this year’s M=9.0 Tohoku, Japan, earthquake was completely unforeseen. The Japanese had expected no larger than a M=8 quake in the Japan trench, 1/30 th the size of the Tohoku temblor. This year also saw the devastating M=6.3 Christchurch, New Zealand earthquake and...

Date published: October 21, 2013
Status: Active

Transport of dissolved organic matter by river networks from mountains to the sea: a re-examination of the role of flow across temporal and spatial scales

The transport of dissolved organic matter (DOM) by rivers is an important component of the global carbon cycle, affects ecosystems and water quality, and reflects biogeochemical and hydrological processes in watersheds. Understanding the fundamental relationships between discharge and DOM concentration and composition reveals important information about watershed flow paths, soil flushing,...

Date published: October 21, 2013
Status: Active

Modeling species response to environmental change: development of integrated, scalable Bayesian models of population persistence

Estimating species response to environmental change is a key challenge for ecologists and a core mission of the USGS. Effective forecasting of species response requires models that are detailed enough to capture critical processes and at the same time general enough to allow broad application. This tradeoff is difficult to reconcile with most existing methods. We propose to extend and combine...