A5024705669- Hydrology and Watershed Management Studies
- Climate variability and models
- Hydrology and Drought Analysis
- Tree-ring climate responses
- Groundwater and Isotope Geochemistry
- Plant Water Relations and Carbon Dynamics
- Groundwater flow and contamination studies
- Flood Risk Assessment and Management
- Cryospheric studies and observations
- Hydrological Forecasting Using AI
- Meteorological Phenomena and Simulations
- Hydrology and Sediment Transport Processes
- Fish Ecology and Management Studies
- Precipitation Measurement and Analysis
- Water Systems and Optimization
- Reservoir Engineering and Simulation Methods
- Water resources management and optimization
- Dam Engineering and Safety
- Water Quality Monitoring and Analysis
- Spatial and Panel Data Analysis
- Water Quality and Resources Studies
- Soil Geostatistics and Mapping
- Hydraulic flow and structures
- Karst Systems and Hydrogeology
- demographic modeling and climate adaptation
United States Bureau of Reclamation
2011-2024
Denver Federal Center
2010-2017
Amec Foster Wheeler (United States)
2009
University of Colorado Boulder
2003-2007
Cooperative Institute for Research in Environmental Sciences
2004-2005
UNESCO
2001
Asian Institute of Technology
1995-1999
Geological Survey of India
1979-1982
A number of statistical methods that are used to provide local-scale ensemble forecasts precipitation and temperature do not contain realistic spatial covariability between neighboring stations or temporal persistence for subsequent forecast lead times. To demonstrate this point, output from a global-scale numerical weather prediction model is in stepwise multiple linear regression approach downscale individual located around four study basins the United States. Output downscaled times up 14...
A K‐ nearest neighbor ( K ‐ nn ) resampling scheme is presented that simulates daily weather variables, and consequently seasonal climate spatial temporal dependencies, at multiple stations in a given region. strategy introduced uses the algorithm to produce alternative data sets conditioned upon hypothetical scenarios, e.g., warmer‐drier springs, warmer‐wetter winters, so on. This technique allows for creation of ensembles scenarios can be used integrated assessment water resource...
Across the Upper Missouri River Basin, recent drought of 2000 to 2010, known as “turn-of-the-century drought,” was likely more severe than any in instrumental record including Dust Bowl drought. However, until now, adequate proxy records needed better understand this event with regard long-term variability have been lacking. Here we examine 1,200 y streamflow from a network 17 new tree-ring–based reconstructions for gages across upper basin and an independent reconstruction warm-season...
Statistical downscaling provides a technique for deriving local‐scale information of precipitation and temperature from numerical weather prediction model output. The K ‐nearest neighbor ( ‐nn) is new analog‐type approach that used in this paper to downscale the National Centers Environmental Prediction 1998 medium‐range forecast ‐nn algorithm queries days similar given feature vector archive using empirical orthogonal function analysis identifies subset ) day. These are then weighted...
Abstract. Future flood frequency for the upper Truckee River basin (UTRB) is assessed using non-stationary extreme value models and design-life risk methodology. Historical floods are simulated at two UTRB gauge locations, Farad Reno, Variable Infiltration Capacity (VIC) model Generalized Extreme Value (GEV) models. The GEV fit to cool season (November–April) monthly maximum flows historical precipitation totals average temperature. distributions subsequently calculated downscaled...
Abstract The ongoing 22‐year drought in the Upper Colorado River Basin (UCRB) has been extremely severe, even context of longest available tree‐ring reconstruction annual flow at Lees Ferry, Arizona, dating back to 762 CE. While many southwestern assessments have limited past 1,200 years, longer paleorecords moisture variability do exist for UCRB. Here, gridded drought‐atlas data UCRB domain along with naturalized streamflow from instrumental period (1906–2021) are used a K ‐nearest neighbor...
Abstract Principal component analysis is a data reduction technique used to identify the important components or factors that explain most of variance system. This was extended evaluating ground water monitoring network where variables are wells. The objective wells in predicting dynamic variation potentiometric head at location. demonstrated through an application Bangkok area. carried out for all aquifer, and ranking scheme based on frequency occurrence particular well as principal...
Abstract Process-based hydrologic models require extensive meteorological forcing data, including data on precipitation, temperature, shortwave and longwave radiation, humidity, surface pressure, wind speed. Observations of precipitation temperature are more common than other variables; consequently, speed often must be either estimated using empirical relationships with or obtained from numerical weather prediction models. This study examines two climate datasets different methods to...
Abstract Spatially distributed historical meteorological forcings (temperature and precipitation) are commonly incorporated into modeling efforts for long-term natural resources planning. For water management decisions, it is critical to understand the uncertainty associated with different choices made in hydrologic impact assessments (choice of model, choice forcing dataset, calibration strategy, etc.). This paper evaluates differences among four used datasets their impacts on streamflow...
Abstract Understanding groundwater‐budget components, particularly groundwater recharge, is important to sustainably manage both and surface water supplies in the Colorado River basin now future. This study quantifies projected changes upper (UCRB) recharge from recent historical (1950–2015) through future (2016–2099) time periods, using a distributed‐parameter model with downscaled climate data 97 Coupled Model Intercomparison Project Phase 5 projections. Simulated UCRB generally expected...
Abstract Drought has affected much of the western United States since about year 2000, including Upper Colorado River Basin (UCRB). Using a time series UCRB streamflow derived from tree‐ring based reconstruction for years 1 CE through 1905 CE, together with naturalized values 1906 2021 we identify 51 drought events, 2000–2021 drought. Although recent been relatively severe, it is not most severe events identified. Results also indicate that natural variability combined projected climate...
Abstract This study compares methods to incorporate climate information into the National Weather Service River Forecast System (NWSRFS). Three small-to-medium river subbasins following roughly along a longitude in Colorado basin with different El Niño–Southern Oscillation signals were chosen as test basins. Historical ensemble forecasts of spring runoff for each generated using modeled hydrologic states and historical precipitation temperature observations Ensemble Streamflow Prediction...
As multicentury records of natural hydrologic variability, tree ring reconstructions streamflow have proven valuable in water resources planning and management. All previous used parametric methods, most often regression, to develop a model relating set data target hydrology. In this paper, we present the first development application K nearest neighbor ( NN) nonparametric method reconstruct naturalized annual ensembles from chronology Upper Colorado River Basin region. The is developed...
Abstract We examine the characteristics of 3 day total extreme precipitation in western United States. Coherent seasonal spatial patterns timing and magnitude are evident data, motivating a seasonally based analysis. Using clustering method that is consistent with value theory, we identify coherent regions for extremes vary seasonally. Based on storm back trajectory analysis, demonstrate unique moisture sources dominant pathways each region. In winter Pacific Ocean source across west, but...
A method is introduced to generate conditioned daily precipitation and temperature time series at multiple stations. The resamples data from the historical record “nens” times for period of interest (nens = number ensemble members) reorders members reconstruct observed spatial (intersite) temporal correlation statistics. weather generator model applied 2307 stations in contiguous United States shown reproduce between neighboring stations, variables (e.g., temperature), subsequent days...
Management of water temperatures in the Columbia River Basin (Washington) is critical because projects have substantially altered habitat Endangered Species Act listed species, such as salmon, throughout basin. This most important tributaries to Columbia, Methow River, where spawning and rearing life stages these cold fishes occurs. Climate change projections generally predict increasing air across western United States, with less confidence regarding shifts precipitation. As rise, we...
Abstract. The current drought over the Colorado River Basin has raised concerns that US Department of Interior, Bureau Reclamation (Reclamation) may impose water shortages lower portion basin for first time in history. guidelines determine levels shortage are affected by relatively short-term (3 to 7 month) forecasts determined Forecast Center (CBRFC) using National Weather Service (NWS) Forecasting System (RFS) hydrologic model. While these CBRFC useful, managers within interested long-term...
Abstract We propose a Bayesian hierarchical model for spatial extremes on large domain. In the data layer Gaussian elliptical copula having generalized extreme value (GEV) marginals is applied. Spatial dependence in GEV parameters captured with latent regression spatially varying coefficients. Using composite likelihood approach, we are able to efficiently incorporate precipitation set, which includes stations missing data. The demonstrated by application fall at approximately 2600 covering...
There has been a considerable amount of research linking climatic variability to hydrologic responses in the western United States. Although much effort spent assess and predict changes surface water resources, little done understand how events affect groundwater resources. This study focuses on characterizing quantifying effects large, multiyear, quasi-decadal recharge northern Utah portion Great Basin for period 1960–2013. Annual level data were analyzed with characterize conditions...
Abstract This study introduces medium-range meteorological ensemble inputs of temperature and precipitation into the Ensemble Streamflow Prediction component National Weather Service River Forecast System (NWSRFS). The Climate Diagnostics Center (CDC) produced a reforecast archive model forecast runs from dynamically frozen version Medium-Range (MRF) model. was used to derive statistical relationships between MRF variables historical basin-average temperatures. latter are feed (ESP) NWSRFS....