Lawrence Martz | University of Saskatchewan (original) (raw)
Papers by Lawrence Martz
North American Water and …
Numerical algorithms are presented to estimate the length, width and slope of rectangular planes ... more Numerical algorithms are presented to estimate the length, width and slope of rectangular planes representing irregularly shaped overland contributing areas defined on raster Digital Elevation Models (DEM). The strength of the procedure lies in that each flow path on the raster overland area is considered in the determination of the representative value for the entire rectangular plane as opposed to relying on a lumped, single flow path approach. The flow path parameters required by the algorithms are derived from raster maps of elevation (DEM) , flow direction
AGU Fall Meeting Abstracts, Dec 1, 2019
AGU Fall Meeting Abstracts, Dec 1, 2018
this thesis freely available for inspection. Moreover, the author has agreed that permission for ... more this thesis freely available for inspection. Moreover, the author has agreed that permission for extensive copying of this thesis for scholarly purposes may be granted by the professor or professors who supervised the thesis work recorded herein or, in their absence, by the Head of the Department or the Dean of the College in which the thesis work was done. It is understood that due recognition will be given to the author of this thesis and to the University of Saskatchewan in any use of the material in this thesis. Copying or publication or any other use of the thesis for financial gain without approval by the University of Saskatchewan and the author's written permission is prohibited.
Prairie Women's Centre of Excellence, …, 2007
estimation methods in a Canadian prairie landscape. Hydrol. Processes, 22, 2801-2815.
In July 2005, several scientists from the Mackenzie GEWEX (Global Energy and Water Cycle Experime... more In July 2005, several scientists from the Mackenzie GEWEX (Global Energy and Water Cycle Experiment) Study, known as MAGS, met with aboriginal people in Deline on the shore of Great Bear Lake to exchange information on climate and water in the region. Topics discussed pertained directly to the northern environment, and they included climate variability and change, wind, lightning, lake ice, lake level, and streamflow. The traditional knowledge shared by the residents is a rich source of local expertise about the landscape and climate systems of the Deline area, while the scientific knowledge provided by MAGS presents a scientific basis for many observed climate and water phenomena, particularly on a broad regional scale. Through cordial and open discussions, the meeting facilitated the sharing of traditional knowledge and scientific results. The meeting enhanced the potential for traditional knowledge to help direct and validate scientific investigations and for scientific knowledge...
GIScience & Remote Sensing
Remote Sensing
Drought is a significant climatic disturbance in grasslands, yet the impact drought caused by glo... more Drought is a significant climatic disturbance in grasslands, yet the impact drought caused by global warming has on grassland phenology is still unclear. Our research investigates the long-term variability of grassland phenology in relation to drought in the Canadian prairies from 1982 to 2014. Based on the start of growing season (SOG) and the end of growing season (EOG) derived from Global Inventory Modeling and Mapping Studies (GIMMS) NDVI3g datasets, we found that grasslands demonstrated complex phenology trends over our study period. We retrieved the drought conditions of the prairie ecozone at multiple time scales from the 1-to 12-month Standardized Precipitation Evapotranspiration Index (SPEI). We evaluated the correlations between the detrended time series of phenological metrics and SPEIs through Pearson correlation analysis and identified the dominant drought where the maximum correlations were found for each ecozone and each phenological metric. The dominant drought over preceding months account for 14-33% and 26-44% of the year-to-year variability of SOG and EOG, respectively, and fewer water deficits would favor an earlier SOG and delayed EOG. The drought-induced shifts in SOG and EOG were determined based on the correlation between the dominant drought and the year-to-year variability using ordinary least square (OLS) method. Our research also quantifies the correlation between precipitation and the evolution of the dominant droughts and the drought-induced shifts in grassland phenology. Every millimeter (mm) increase in precipitation accumulated over the dominant periods would cause SOG to occur 0.06-0.21 days earlier, and EOG to occur 0.23-0.45 days later. Our research reveals a complex phenology response in relation to drought in the Canadian prairie grasslands and demonstrates that drought is a significant factor in the timing of both SOG and EOG. Thus, it is necessary to include drought-related climatic variables when predicting grassland phenology response to climate change and variability.
Cartographic Perspectives, 2003
GIS for Water Resource and Watershed Management, 2002
Page 24. CHAPTER 1 Channel Network Delineation and Watershed Segmentation in the TOPAZ Digital La... more Page 24. CHAPTER 1 Channel Network Delineation and Watershed Segmentation in the TOPAZ Digital Landscape Analysis System Lawrence W. Martz and Jurgen Garbrecht INTRODUCTION Research over the past decade ...
GIS for Water Resource and Watershed Management, 2002
Page 238. CHAPTER 17 Technological Advances in Automated Land Surface Parameterization from Digit... more Page 238. CHAPTER 17 Technological Advances in Automated Land Surface Parameterization from Digital Elevation Models Jurgen Garbrecht, Lawrence W. Martz, and Patrick J. Starks INTRODUCTION Topography plays ...
GIS for Water Resource and Watershed Management, 2002
Page 34. CHAPTER 2 Assessing the Performance of Automated Watershed Segmentation from Digital Ele... more Page 34. CHAPTER 2 Assessing the Performance of Automated Watershed Segmentation from Digital Elevation Models By Jurgen Garbrecht and Lawrence W. Martz INTRODUCTION Watershed segmentation and channel ...
Canadian Water Resources Journal, 1988
Sub-watershed contributions to the suspended sediment yield of Spring Creek Watershed, a 113 km2 ... more Sub-watershed contributions to the suspended sediment yield of Spring Creek Watershed, a 113 km2 forested area in northwestern Alberta, were examined. The analysis was based on a five year record of suspended sediment and water discharge from Spring Creek Watershed and five of its sub-watersheds, compiled as part of the Canadian contribution to the International Hydrological Decade Programme. The gauged sub-watersheds accounted lor 76 percent of the total area of Spring Creek Watershed, 82 percent of its total water yield, but only B percent of its total sediment yield. Annual sediment yield patterns and sediment rating curve analysis indicated that sediment discharge from Spring Creek Watershed was largely independent of the erosional processes operating in the sub-watersheds. A simple conceptual model is proposed which explains the interaction between the sediment discharge of the subwatersheds and that of Spring Creek Watershed by identifyrng the major sediment sinks and sources in the study area. The model suggests that runoff and sediment generation are not spatially coincident processes and that over 90 percent of the watershed sediment yield is derived from less than 1 percent of its area. The model is considered to be generally applicable to the sediment regime of other, similar watersheds in the region.
Canadian Water Resources Journal, 2004
This study was conducted to evaluate the accuracy of hydrological stream networks derived from tw... more This study was conducted to evaluate the accuracy of hydrological stream networks derived from two digital elevation models (DEM) and two remote sensing images for a tributary of the Frenchman River in southwest Saskatchewan. This project also provides practical insight into the use of Indian Remote Sensing (IRS) Satellite imaging for hydrological network delineation. IRS images and orthophotographs were used for manual network delineation. Canadian Digital Elevation Data (CDED) and a digital elevation model (DEM) constructed from point and line elevation information from the orthophotographs were used for automated network delineation in program TOPAZ (TOpographic PArameteriZation). Each delineated network was compared with the same National Topographic Series (NTS) blue-line network, as it was assumed the NTS network was the most accurate available representation of the actual drainage network. The networks were compared by visual overlay, Kappa Index of Agreement (KIA) and network statistics such as bifurcation and stream length ratios. The IRS, orthophotograph, and CDED networks were suitable data sources for network delineation, whereas the ortho DEM was not. The major differences between the networks were in the first order streams with consequent effects on higher order streams. First order streams are difficult to delineate in a consistent and accurate manner in a digital environment because of the nature of data sources and differences in the computation processes. As a result, it is concluded that field surveys should be considered in conjunction with digital manipulation for the accurate classification of first order streams.
North American Water and …
Numerical algorithms are presented to estimate the length, width and slope of rectangular planes ... more Numerical algorithms are presented to estimate the length, width and slope of rectangular planes representing irregularly shaped overland contributing areas defined on raster Digital Elevation Models (DEM). The strength of the procedure lies in that each flow path on the raster overland area is considered in the determination of the representative value for the entire rectangular plane as opposed to relying on a lumped, single flow path approach. The flow path parameters required by the algorithms are derived from raster maps of elevation (DEM) , flow direction
AGU Fall Meeting Abstracts, Dec 1, 2019
AGU Fall Meeting Abstracts, Dec 1, 2018
this thesis freely available for inspection. Moreover, the author has agreed that permission for ... more this thesis freely available for inspection. Moreover, the author has agreed that permission for extensive copying of this thesis for scholarly purposes may be granted by the professor or professors who supervised the thesis work recorded herein or, in their absence, by the Head of the Department or the Dean of the College in which the thesis work was done. It is understood that due recognition will be given to the author of this thesis and to the University of Saskatchewan in any use of the material in this thesis. Copying or publication or any other use of the thesis for financial gain without approval by the University of Saskatchewan and the author's written permission is prohibited.
Prairie Women's Centre of Excellence, …, 2007
estimation methods in a Canadian prairie landscape. Hydrol. Processes, 22, 2801-2815.
In July 2005, several scientists from the Mackenzie GEWEX (Global Energy and Water Cycle Experime... more In July 2005, several scientists from the Mackenzie GEWEX (Global Energy and Water Cycle Experiment) Study, known as MAGS, met with aboriginal people in Deline on the shore of Great Bear Lake to exchange information on climate and water in the region. Topics discussed pertained directly to the northern environment, and they included climate variability and change, wind, lightning, lake ice, lake level, and streamflow. The traditional knowledge shared by the residents is a rich source of local expertise about the landscape and climate systems of the Deline area, while the scientific knowledge provided by MAGS presents a scientific basis for many observed climate and water phenomena, particularly on a broad regional scale. Through cordial and open discussions, the meeting facilitated the sharing of traditional knowledge and scientific results. The meeting enhanced the potential for traditional knowledge to help direct and validate scientific investigations and for scientific knowledge...
GIScience & Remote Sensing
Remote Sensing
Drought is a significant climatic disturbance in grasslands, yet the impact drought caused by glo... more Drought is a significant climatic disturbance in grasslands, yet the impact drought caused by global warming has on grassland phenology is still unclear. Our research investigates the long-term variability of grassland phenology in relation to drought in the Canadian prairies from 1982 to 2014. Based on the start of growing season (SOG) and the end of growing season (EOG) derived from Global Inventory Modeling and Mapping Studies (GIMMS) NDVI3g datasets, we found that grasslands demonstrated complex phenology trends over our study period. We retrieved the drought conditions of the prairie ecozone at multiple time scales from the 1-to 12-month Standardized Precipitation Evapotranspiration Index (SPEI). We evaluated the correlations between the detrended time series of phenological metrics and SPEIs through Pearson correlation analysis and identified the dominant drought where the maximum correlations were found for each ecozone and each phenological metric. The dominant drought over preceding months account for 14-33% and 26-44% of the year-to-year variability of SOG and EOG, respectively, and fewer water deficits would favor an earlier SOG and delayed EOG. The drought-induced shifts in SOG and EOG were determined based on the correlation between the dominant drought and the year-to-year variability using ordinary least square (OLS) method. Our research also quantifies the correlation between precipitation and the evolution of the dominant droughts and the drought-induced shifts in grassland phenology. Every millimeter (mm) increase in precipitation accumulated over the dominant periods would cause SOG to occur 0.06-0.21 days earlier, and EOG to occur 0.23-0.45 days later. Our research reveals a complex phenology response in relation to drought in the Canadian prairie grasslands and demonstrates that drought is a significant factor in the timing of both SOG and EOG. Thus, it is necessary to include drought-related climatic variables when predicting grassland phenology response to climate change and variability.
Cartographic Perspectives, 2003
GIS for Water Resource and Watershed Management, 2002
Page 24. CHAPTER 1 Channel Network Delineation and Watershed Segmentation in the TOPAZ Digital La... more Page 24. CHAPTER 1 Channel Network Delineation and Watershed Segmentation in the TOPAZ Digital Landscape Analysis System Lawrence W. Martz and Jurgen Garbrecht INTRODUCTION Research over the past decade ...
GIS for Water Resource and Watershed Management, 2002
Page 238. CHAPTER 17 Technological Advances in Automated Land Surface Parameterization from Digit... more Page 238. CHAPTER 17 Technological Advances in Automated Land Surface Parameterization from Digital Elevation Models Jurgen Garbrecht, Lawrence W. Martz, and Patrick J. Starks INTRODUCTION Topography plays ...
GIS for Water Resource and Watershed Management, 2002
Page 34. CHAPTER 2 Assessing the Performance of Automated Watershed Segmentation from Digital Ele... more Page 34. CHAPTER 2 Assessing the Performance of Automated Watershed Segmentation from Digital Elevation Models By Jurgen Garbrecht and Lawrence W. Martz INTRODUCTION Watershed segmentation and channel ...
Canadian Water Resources Journal, 1988
Sub-watershed contributions to the suspended sediment yield of Spring Creek Watershed, a 113 km2 ... more Sub-watershed contributions to the suspended sediment yield of Spring Creek Watershed, a 113 km2 forested area in northwestern Alberta, were examined. The analysis was based on a five year record of suspended sediment and water discharge from Spring Creek Watershed and five of its sub-watersheds, compiled as part of the Canadian contribution to the International Hydrological Decade Programme. The gauged sub-watersheds accounted lor 76 percent of the total area of Spring Creek Watershed, 82 percent of its total water yield, but only B percent of its total sediment yield. Annual sediment yield patterns and sediment rating curve analysis indicated that sediment discharge from Spring Creek Watershed was largely independent of the erosional processes operating in the sub-watersheds. A simple conceptual model is proposed which explains the interaction between the sediment discharge of the subwatersheds and that of Spring Creek Watershed by identifyrng the major sediment sinks and sources in the study area. The model suggests that runoff and sediment generation are not spatially coincident processes and that over 90 percent of the watershed sediment yield is derived from less than 1 percent of its area. The model is considered to be generally applicable to the sediment regime of other, similar watersheds in the region.
Canadian Water Resources Journal, 2004
This study was conducted to evaluate the accuracy of hydrological stream networks derived from tw... more This study was conducted to evaluate the accuracy of hydrological stream networks derived from two digital elevation models (DEM) and two remote sensing images for a tributary of the Frenchman River in southwest Saskatchewan. This project also provides practical insight into the use of Indian Remote Sensing (IRS) Satellite imaging for hydrological network delineation. IRS images and orthophotographs were used for manual network delineation. Canadian Digital Elevation Data (CDED) and a digital elevation model (DEM) constructed from point and line elevation information from the orthophotographs were used for automated network delineation in program TOPAZ (TOpographic PArameteriZation). Each delineated network was compared with the same National Topographic Series (NTS) blue-line network, as it was assumed the NTS network was the most accurate available representation of the actual drainage network. The networks were compared by visual overlay, Kappa Index of Agreement (KIA) and network statistics such as bifurcation and stream length ratios. The IRS, orthophotograph, and CDED networks were suitable data sources for network delineation, whereas the ortho DEM was not. The major differences between the networks were in the first order streams with consequent effects on higher order streams. First order streams are difficult to delineate in a consistent and accurate manner in a digital environment because of the nature of data sources and differences in the computation processes. As a result, it is concluded that field surveys should be considered in conjunction with digital manipulation for the accurate classification of first order streams.