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Southern Illinois University Carbondale

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Articles 1 - 8 of 8

Full-Text Articles in Physical and Environmental Geography

Dynamically And Statistically Downscaled Seasonal Simulations Of Maximum Surface Air Temperature Over The Southeastern United States, Young-Kwon Lim, D W. Shin, Steven Cocke, T E. Larow, Justin T. Schoof, James J. O'Brien, Eric P. Chassignet Jan 2007

Dynamically And Statistically Downscaled Seasonal Simulations Of Maximum Surface Air Temperature Over The Southeastern United States, Young-Kwon Lim, D W. Shin, Steven Cocke, T E. Larow, Justin T. Schoof, James J. O'Brien, Eric P. Chassignet

Publications

Coarsely resolved surface air temperature (2 m height) seasonal integrations from the Florida State University/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU/COAPS GSM) (~1.8º lon.-lat. (T63)) for the period of 1994 to 2002 (March through September each year) are downscaled to a fine spatial scale of ~20 km. Dynamical and statistical downscaling methods are applied for the southeastern United States region, covering Florida, Georgia, and Alabama. Dynamical downscaling is conducted by running the FSU/COAPS Nested Regional Spectral Model (NRSM), which is nested into the domain of the FSU/COAPS GSM. We additionally present a new statistical downscaling method. The rationale …

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Downscaling Daily Maximum And Minimum Air Temperature In The Midwestern Usa: A Hybrid Empirical Approach, Justin T. Schoof, S C. Pryor, S M. Robeson Jan 2007

Downscaling Daily Maximum And Minimum Air Temperature In The Midwestern Usa: A Hybrid Empirical Approach, Justin T. Schoof, S C. Pryor, S M. Robeson

Publications

A new hybrid empirical downscaling technique is presented and applied to assess 21st century projections of maximum and minimum daily surface air temperatures (Tmax, Tmin) over the Midwestern USA. Our approach uses multiple linear regression to downscale the seasonal variations of the mean and standard deviation of daily Tmax and Tmin and the lag-0 and lag-1 correlations between daily Tmax and Tmin based on GCM simulation of the large-scale climate. These downscaled parameters are then used as inputs to a stochastic weather generator to produce time series of the daily Tmax and Tmin at 26 surface stations, in three time …

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Winds Of Change?: Projections Of Near-Surface Winds Under Climate Change Scenarios, S C. Pryor, Justin T. Schoof, R J. Barthelmie Jan 2006

Winds Of Change?: Projections Of Near-Surface Winds Under Climate Change Scenarios, S C. Pryor, Justin T. Schoof, R J. Barthelmie

Publications

Changes in near–surface wind speeds due to global climate change may have profound geophysical and societal impacts. However, Global Climate Models (GCMs) are unable to replicate the historically observed magnitude and spatial variability of wind speeds, so we apply a downscaling technique to generate probability distributions of wind speeds at sites in northern Europe for historical periods (1961–1990 and 1982–2000) and two future periods (2046–2065, 2081–2100). Projections for the twenty-first century (C21st) indicate no evidence of substantial evolution relative to the end of the twentieth century (C20th), although there is increased divergence of results from downscaling of different GCMs toward …

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An Evaluation Of Two Gcms: Simulation Of North American Teleconnection Indices And Synoptic Phenomena, Justin T. Schoof, S C. Pryor Jan 2006

An Evaluation Of Two Gcms: Simulation Of North American Teleconnection Indices And Synoptic Phenomena, Justin T. Schoof, S C. Pryor

Publications

We evaluate the ability of two coupled atmospheric–oceanic GCMs – the Hadley Center’s third generation coupled climate model (HadCM3) and the Canadian Center for Climate Modeling and Analysis second-generation coupled model (CGCM2) – to simulate the North Atlantic Oscillation (NAO), the Pacific North American teleconnection pattern (PNA), and map patterns in the Midwest region of the United States, relative to NCEP/NCAR reanalysis (NNR) data. The observed (NNR-derived) and GCM-derived probability distributions and temporal behavior of the daily teleconnection indices exhibit agreement over the 1990–2001 reference period, and both GCMs successfully reproduce the range of 500-hPa map patterns over the study …

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Empirical Downscaling Of Wind Speed Probability Distributions, S C. Pryor, Justin T. Schoof, R J. Barthelmie Jan 2005

Empirical Downscaling Of Wind Speed Probability Distributions, S C. Pryor, Justin T. Schoof, R J. Barthelmie

Publications

This paper presents a novel approach to developing empirically downscaled estimates of near-surface wind speed and energy density and results from application of the technique to multiple stations in northern Europe. The downscaling takes a probabilistic approach in that it uses the mean and standard deviation of relative vorticity at 500 hPa and mean sea level pressure gradients computed using output from the ECHAM4/OPYC3 atmosphere-ocean general circulation model as the predictors and parameters of the wind speed probability distribution at surface stations as the predictands.We demonstrate that this approach generates accurate depictions of the wind climate during the conditioning period …

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The Impact Of Non-Stationarities In The Climate System On The Definition Of "A Normal Wind Year": A Case Study From The Baltic, S C. Pryor, R J. Barthelmie, Justin T. Schoof Jan 2005

The Impact Of Non-Stationarities In The Climate System On The Definition Of "A Normal Wind Year": A Case Study From The Baltic, S C. Pryor, R J. Barthelmie, Justin T. Schoof

Publications

Wind speeds over the Baltic significantly increased over the second half of the 20th century (C20th), with the majority of the increase being focused on the upper quartile of the wind speed distribution and in the southwest of the region. These changes have potentially profound implications for the wind energy resource. For example, based on the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data it is shown that, owing to this non-stationarity, using the normalization period of 1987–98 to determine the wind resource (as in the Danish wind index) leads to overestimation of the wind energy …

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Evaluation Of The Ncep/Ncar Reanalysis In Terms Of Synoptic Scale Phenomea: A Case Study From The Midwestern Usa, Justin T. Schoof, S C. Pryor Jan 2003

Evaluation Of The Ncep/Ncar Reanalysis In Terms Of Synoptic Scale Phenomea: A Case Study From The Midwestern Usa, Justin T. Schoof, S C. Pryor

Publications

We evaluate the ability of the National Centers for Environmental Prediction (NCEP)–National Center for Atmosphere Research (NCAR) reanalysis to represent the synoptic-scale climate of the Midwestern USA relative to radiosonde data. Independent, automated synoptic classifications, based on rotated principal component analysis (PCA) of 500 hPa geopotential heights, 850 hPa air temperatures, and 200 hPa wind speeds and a two-step clustering algorithm, result in a 15-type NCEP–NCAR synoptic classification and a 14-type radiosonde classification. The classifications are examined in terms of similarities and differences in the modes of variance manifest in the PCA solutions, the spatial patterns and variability of input …

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Downscaling Temperature And Precipitation: A Comparison Of Regression-Based Methods And Artificial Neural Networks, Justin T. Schoof, S C. Pryor Jan 2001

Downscaling Temperature And Precipitation: A Comparison Of Regression-Based Methods And Artificial Neural Networks, Justin T. Schoof, S C. Pryor

Publications

A comparison of two statistical downscaling methods for daily maximum and minimum surface air temperature, total daily precipitation and total monthly precipitation at Indianapolis, IN, USA, is presented. The analysis is conducted for two seasons, the growing season and the non-growing season, defined based on variability of surface air temperature. The predictors used in the downscaling are indices of the synoptic scale circulation derived from rotated principal components analysis (PCA) and cluster analysis of variables extracted from an 18-year record from seven rawinsonde stations in the Midwest region of the United States. PCA yielded seven significant components for the growing …

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