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Filters: Types: Journal Citation (X) > partyWithName: Piechota, Thomas C (X)

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This research investigates the interannual variability of soil moisture as related to large-scale climate variability and also evaluates the spatial and temporal variability of modeled deep layer (40?140 cm) soil moisture in the Upper Colorado River Basin (UCRB). A three layers hydrological model VIC-3L (Variable Infiltration Capacity Model ? 3 layers) was used to generate soil moisture in the UCRB over a 50-year period. By using wavelet analysis, deep layer soil moisture was compared to the Palmer Drought Severity Index (PDSI), precipitation, and streamflow to determine whether deep soil moisture is an indicator of climate extremes. Wavelet and coherency analysis for the UCRB indicated a strong relationship between...
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The study presented here utilized long-term streamflow records (over 500 years) to investigate the influence of interannual/interdecadal climate variability on the Colorado River basin. 19 unimpaired water year streamflow stations were reconstructed utilizing partial least square regression using standard tree ring chronologies. The spatial and temporal variability of drought was evaluated for all the stations for the different centuries in the record. Finally, the relationship between individual impact of ENSO, PDO, and AMO and its combined effect on streamflow was determined using the non parametric Rank Sum test for different lag years (0, +1, +2, and +3) of streamflow. This research also determined the change...
This study focuses on regionalization and reconstruction of April 1 snow water equivalent (SWE) of snow courses stations located in the Upper Colorado River basin (UCRB) and evaluates regional drought scenarios for the last 480 years. Rotated principal component analysis (PCA) and cluster analysis were used to regionalize the snow course stations in the UCRB. Both methods of regionalization identified four regions of snow course stations, which were spatially distributed in the regions (east, west, north and south). Then, partial least squares regression (PLSR) was used to reconstruct three regional SWE time series in the UCRB based on residual tree-ring chronologies. Tree-ring chronologies that were positively...
Historical stream flow records and the forecast for 2004 make the current (1999?2004) drought in the southwestern United States the worst one in the past 80 years for portions of the Upper Colorado River Basin (UCRB). For the Colorado River (near Cisco, Utah), the cumulative stream flow deficit (departure from long-term mean) for the current drought is almost 11 km3, or approximately 2 years of average stream flow.Although the current drought is the most significant,based on historical stream flow records, is it the worst ever? Published in Eos, Transactions, American Geophysical Union, volume 85, issue 32, on pages 301 - 308, in 2004.
Pacific and Atlantic Ocean sea surface temperatures (SSTs) were used as predictors in a long lead-time streamflow forecast model in which the partial least squares regression (PLSR) technique was used with over 600 unimpaired streamflow stations in the continental United States. Initially, PLSR calibration (or test) models were developed for each station, using the previous spring-summer Pacific (or Atlantic) Ocean SSTs as predictors. Regions were identified in the Pacific Northwest, Upper Colorado River Basin, Midwest, and Atlantic states in which Pacific Ocean SSTs resulted in skillful forecasts. Atlantic Ocean SSTs resulted in significant regions being identified in the Pacific Northwest, Midwest, and Atlantic...
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Given the importance of Upper Colorado River Basin (UCRB) snowpack as the primary driver of streamflow (water supply) for the southwestern United States, the identification of Pacific Ocean climatic drivers (e.g., sea surface temperature (SST) variability) may prove valuable in long-lead-time forecasting of snowpack in this critical region. Previous research efforts have identified El Ni�o?Southern Oscillation (ENSO) and Pacific Decadel Oscillation (PDO) as the main drivers for western U.S. snowpack, but these drivers have limited influence on regional (Utah and Colorado) UCRB snowpack. The current research applies for the first time the Singular Value Decomposition (SVD) statistical method to Pacific Ocean SSTs...
    map background search result map search result map Identification of Pacific Ocean sea surface temperature influences of Upper Colorado River Basin snowpack Associations of interdecadal/interannual climate variability and long-term colorado river basin streamflow Identification of Pacific Ocean sea surface temperature influences of Upper Colorado River Basin snowpack Associations of interdecadal/interannual climate variability and long-term colorado river basin streamflow