Kevin Shook

Bio: Kevin Shook is an academic researcher from University of Saskatchewan. The author has contributed to research in topics: Snow & Surface runoff. The author has an hindex of 13, co-authored 30 publications receiving 1062 citations.

An evaluation of snow accumulation and ablation processes for land surface modelling

Abstract: This paper discusses the development and testing of snow algorithms with specific reference to their use and application in land surface models. New algorithms, developed by the authors, for estimating snow interception in forest canopies, blowing snow transport and sublimation, snow cover depletion and open environment snowmelt are compared with field measurements. Existing algorithms are discussed and compared with field observations. Recommendations are made with respect to: (a) density of new and aged snow in open and forest environments; (b) interception of snow by evergreen canopies; (c) redistribution and sublimation of snow water equivalent by blowing snow; (d) depletion in snow-covered area during snowmelt; (e) albedo decay during snowmelt; (f) turbulent transfer during snowmelt; and (g) soil heat flux during meltwater infiltration into frozen soils. Preliminary evidence is presented, suggesting that one relatively advanced land surface model, CLASS, significantly underestimates the timing of snowmelt and snowmelt rates in open environments despite overestimating radiation and turbulent contributions to melt. The cause(s) may be due to overestimation of ground heat loss and other factors. It is recommended that further studies of snow energetics and soil heat transfer in frozen soils be undertaken to provide improvements for land surface models such as CLASS, with particular attention paid to establishing the reliability of the models in invoking closure of the energy equation. #1998 John Wiley & Sons, Ltd.

Memory effects of depressional storage in Northern Prairie hydrology

Abstract: The hydrography of the Prairies of western Canada and the north-central United States is characterized by drainage into small depressions, forming wetlands rather than being connected to a large-scale drainage system. In droughts, many of these water bodies completely dry up, while in wet periods, their expansion can cause infrastructure damage. As wetlands expand and contract with changing water levels, connections among them are formed and broken. The change in hydrographic connectivity dynamically changes the hydrological response of basins by controlling the area of the basin which contributes discharge to local streams.The objective of this research was to determine the behaviour of prairie basins dominated by wetlands through two sets of simulations. The first consisted of application and removal of water (simulating runoff and evaporation) from a LiDAR digital elevation model (DEM) of a small basin in the south-east of the Canadian Province of Saskatchewan. Plots of water surface area and of contributing area against depressional storage showed evidence of hysteresis, in that filling and emptying curves followed differing paths, indicating the existence of memory of prior conditions. It was demonstrated that the processes of filling and emptying produced differing changes in the frequency distributions of wetland areas, resulting in the observed hysteresis.Because the first model was computationally intensive, a second model was built to test the use of simpler wetland representations. The second model used a set of interconnected wetlands, whose frequency distribution and connectivity were derived from the original LiDAR DEM. When subjected to simple applications and removal of simulated water, the second model displayed hysteresis loops similar to those of the first model. The implications for modelling prairie basins are discussed. Copyright © 2011 John Wiley & Sons, Ltd.

Storage dynamics simulations in prairie wetland hydrology models: evaluation and parameterization

Abstract: The contributing areas of streams in the Prairie regions of Canada and the northern U.S. are dominated by complexes of wetlands which store and release water. Prior research has suggested the existence of hysteresis between the total volume of water stored in prairie wetlands within a drainage basin and the basin's contributing area. To simulate the relationship between storage and contributing area in a way that accounts for hysteresis, two wetland hydrology models with vastly different levels of complexity were devised. The fully distributed Wetland Digital Elevation Model (DEM) Ponding Model (WDPM) applies simple fluxes of runoff and evaporation to a DEM of a prairie wetland complex. The parameterized Pothole Cascade Model (PCM) applies simulated fluxes of water to collections of conceptual models of wetlands and is less demanding in computations and data. Prior research showed that both models produced hysteretic relationships between water storage and contributing area, but the PCM produced smaller estimates of contributing area than did the WDPM, likely due to its spatial simplification. Using sequential remote sensing observations of wetland area after snowmelt, this study shows that the frequency distribution of the open water areas of prairie wetlands is similar to that produced by the WDPM when the wetlands are close to being completely filled. The remotely sensed observations show evidence of hysteresis in the open water area frequency distributions, as predicted by the fully distributed WDPM. To enable the parameterized PCM to produce the same type of hysteretic relationships as the WDPM, scaling relationships between the maximum area of a wetland and the area of upland draining into it were included. The parameterized PCM is suitable for application with prairie snow redistribution, snowmelt, infiltration, runoff and evapotranspiration routines as part of semi-distributed hydrological modelling of prairie wetland basins such as that implemented in the Cold Regions Hydrological Model. Copyright © 2013 John Wiley & Sons, Ltd.

Changes in the hydrological character of rainfall on the Canadian prairies

Abstract: Many studies have examined trends in the amount and phase of precipitation on the Canadian prairies over the period of record but without considering the unusual hydrology and hydrography of the region. On the Canadian prairies, runoff is primarily due to spring snowmelt over frozen soils but can also be caused by intense rainfall from summer thunderstorms. The fraction of spring snowmelt forming runoff is strongly influenced by the rate of melt and the presence of ice layers near the surface in frozen soils or at the base of the snowpack, all of which can be influenced by rainfall in the spring and late fall. Precipitation intensities sufficient to cause runoff are generally due to small, intense convective storms, which are prevalent during the summer months. Historical records of the fraction of monthly precipitation falling as rain, obtained from the Historical Adjusted Climate Database for Canada (HACDC), were found to display statistically significant increasing trends over the periods 1901–2000 and 1951–2000 at many locations on the Canadian prairies. The fraction of stations showing significant trends, and the importance of the trends, were strongly dependent on the month of the year. Single-day summer rainfalls are believed to be primarily convective in the Canadian prairies. Historical records obtained from HACDC indicate that the hydrological importance of single-day summer rainfalls has not increased and has shown significant decreases at many locations over the periods 1901–2000 and 1951–2000. Conversely, the hydrological importance of summer multiple-day rain events has not decreased and has significantly increased at many locations over the periods analysed. Multiscaling analyses of summer rainfall events demonstrated that the temporal uniformity of rainfall on the Canadian prairies has increased over the periods 1901–2000 and 1951–2000. Analyses of the ratios of rainfall over multiple days demonstrate significant trends over the same periods, confirming the general tendency to temporal uniformity over scales between 1 and 32 days. Longer rain events strongly suggest greater spatial extents for storms and therefore the potential for increasing tendencies to promote basin-scale rainfall–runoff events such as seen in 2011 in the region. Copyright © 2012 John Wiley & Sons, Ltd.

Small-Scale Spatial Structure of Shallow Snowcovers

Abstract: The results of a field study of the small-scale spatial structure of the depth of shallow seasonal snowcovers in prairie and arctic environments are presented. It is shown that the spatial distribution of snow depth is fractal at small scales, becoming random at scales beyond some limiting length. This is due to the autocorrelation of depth at small sampling distances. The transition of fractal to random behaviour is indexed by a 'cutoff length', which is defined by the intersection of the 'fractal' slope and horizontal tangent of a logarithmic plot of the standard deviation of depth versus sampling distance. The magnitude of the cutoff length is related to the degree of macroscopic variability of the underlying topography. An increase in length due to the effects of macroscopic topographic variability on snowcover accumulation is confirmed by de-trending field measurements. The de-trended data shown a cutoff length for wheat stubble and fallow surfaces of approximately 30 m, which is consistent with the distance determined from measurements on 'flat' fields. The implications of the transition of snow depth from fractal to random structure on the scales of snow sampling and modelling are presented. The cutoff length may provide a statistic for stratifying shallow snowcovers, by linking snowcover properties to the underlying topography.

Remote Sensing And Image Interpretation

Abstract: Thank you very much for downloading remote sensing and image interpretation. As you may know, people have look hundreds times for their favorite novels like this remote sensing and image interpretation, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they are facing with some malicious virus inside their computer. remote sensing and image interpretation is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the remote sensing and image interpretation is universally compatible with any devices to read.

RAMS 2001: Current status and future directions

Abstract: ¶An overview of the Regional Atmospheric Modeling System (RAMS) is presented. We focus on new developments in the RAMS physics and computational algorithms since 1992. We also summarize some of the recent applications of RAMS that includes synoptic-scale weather systems and climate studies, to small-scale research using RAMS configured as a large eddy simulation model or to even flow around urban buildings. The applications include basic research on clouds, cloud systems, and storms, examination of interactions between tropical deep convective systems and ocean circulations, simulations of tropical cyclones, extreme precipitation estimation, regional climatic studies of the interactions between the atmosphere and the biosphere or snow-covered land-surfaces, prototype realtime mesoscale numerical weather prediction, air pollution applications, and airflow around buildings.

A decade of Predictions in Ungauged Basins (PUB)—a review

Abstract: The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS), launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23–25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power. This paper reviews the work that has been done under the six science themes of the PUB Decade and outlines the challenges ahead for the hydrological sciences community.Editor D. KoutsoyiannisCitation Hrachowitz, M., Savenije, H.H.G., Bloschl, G., McDonnell, J.J., Sivapalan, M., Pomeroy, J.W., Arheimer, B., Blume, T., Clark, M.P., Ehret, U., Fenicia, F., Freer, J.E., Gelfan, A., Gupta, H.V., Hughes, D.A., Hut, R.W., Montanari, A., Pande, S., Tetzlaff, D., Troch, P.A., Uhlenbrook, S., Wagener, T., Winsemius, H.C., Woods, R.A., Zehe, E., and Cudennec, C., 2013. A d...

Mountain Weather and Climate

Abstract: Prefaces Acknowledgements 1. Mountains and their climatological study 2. Geographical controls of mountain meteorological elements 3. Circulation systems related to orography 4. Climatic characteristics of mountains 5. Regional case studies 6. Mountain bioclimatology 7. Changes in mountain climates Appendix General index Author index.

Is this a practical approach

Abstract: 1. Health care is a human right. 2. The care of the individual is at the center of health care, but the whole system needs to work to improve the health of populations. 3. The health care system must treat illness, alleviate suffering and disability, and promote health. 4. Cooperation with each other, those served, and those in other sectors is essential for all who work in health care. 5. All who provide health care must work to improve it. 6. Do no harm.