Thomas M. Lillesand

Estimating the leaf area index of North Central Wisconsin forests using the landsat thematic mapper

Abstract Leaf area index (LAI) is an extremely important structural characteristic of vegetation because it is directly related to the exchange of energy, CO2 and mass from plant canopies at a variety of scales. Research investigating the relationship between forest LAI and satellite data for hardwood and mixed conifer-hardwood forests is lacking, however. The objective of this study was to explore the utility of Landsat-5 Thematic Mapper (TM) data for accurately estimating the LAI of conifer, hardwood, and mixed conifer-hardwood forests in north central Wisconsin. Individual bands and vegetation indices (VIs) calculated from satellite measures of exoatmospheric reflectance were related to the litterfall-estimated LAI of 24 stands. The results showed that individual bands or VIs containing at least one infrared (IR) band (either near- or mid-infrared) or a strong IR component divided data into at least two groups, with each group requiring a different regression line. The primary division was between conifer-dominated and hardwood-doin inated stands. Of the individual bands and VI.s considered, seven were strongly correlated to the LAI of conifer stands (r2=0.69–0.73). For the hardwoods, the best individual band or VI was Green/mid-IR#1 (r2=0.35), although an additional individual band and two VIs did much better using re subset of lower LAI stands (r2=0.60–0.75). For individual bands and VIs not requiring a conifer-hardwood distinction, the sixth Tasseled Cap component was most closely related to LAI (r2=0.60). Multiple-variable models (using LAI as the dependent variable) were found to offer substantial improvement over single-variable models, especially for hardwood stands. We recommend for further consideration a four-variable model for the conifers, and one four-variable and two eight-variable models for the hardwoods.

Mapping lake water clarity with Landsat images in Wisconsin, U.S.A.

Landsat thematic mapper (TM) and enhanced thematic mapper plus (ETM+) images are being used to map lake water clarity region-wide in the Upper Midwest states of Minnesota, Wisconsin, and Michigan using a standardized image processing protocol. In Wisconsin, lake clarity estimates have been produced for 8645 lakes in the 1999-2001 time period. In addition to satellite imagery, the protocol relies on Secchi disk data collected by a network of citizen volunteers for development and validation of models. The most significant term in the regression model relating the satellite imagery to the field data is the ratio of spectral radiance values in the blue and red bands (ratio of Landsat band 1 to Landsat band 3). The resulting database of satellite-derived lake water clarity estimates represents an important new resource for lake managers in the region, and for those studying the linkages between lakes and their surrounding landscapes.

Positional uncertainty in manually digitized map data

Digital map coordinates represent the locations of real world entities. As such, differences can exist between the ‘tru’ and digital database coordinates of those entities. This paper reports on a statistical characterization of positional error in manually-digitized and map-registered point data, the relative contribution of point type and operator to digitization error, and the effects of map media type on the positional uncertainty associated with registration. Manually-digitized point data were collected by four operators from mylar and paper maps. Point locations for a number of different feature types were sampled from United States Geological Survey (USGS) 1:24 000 scale maps. Linear models were used to estimate the variance components due to among-operator, map media, point type and registration effects. The statistical distribution of signed distance deviations for manually-digitized data was leptokurtic relative to a random normal variate. Unsigned deviations averaged 0-054 mm. Squared distance ...

Calibration of thematic mapper thermal data for water surface temperature mapping: Case study on the Great Lakes

Abstract The potential utility of Landsat-5 Thematic Mapper (TM) thermal IR (Band 6) data for measuring and mapping surface water temperatures of the Great Lakes is analyzed. Two contiguous TM scenes were collected on 18 July 1984 over the Green Bay-North Central Lake Michigan and Milwaukee-South Central Lake Michigan regions, respectively. The TM thermal IR data were empirically calibrated using surface reference data. The regression model so developed, was then used to map surface temperature (°C) over the entire TM coverage area. Surface reference data points not used in the original calibration were used to test the predictive capability of the model over a wider geographic area. As part of the Landsat Image Data Quality Analysis effort (LIDQA), Bartolucci et al. (1985) have investigated the absolute calibration of TM thermal IR data. Application of these calibration equations to our data set verified their accuracy, resulting in a root mean square error of less than I(/dg)C.

Monitoring River Plume Transport and Mesoscale Circulation in Green Bay, Lake Michigan, Through Satellite Remote Sensing

Abstract This study investigates the transport and fate of the Fox River plume and the general circulation patterns within Lake Michigans Green Bay utilizing satellite remote sensing imagery (Landsat TM and NOAA AVHRR). The calibrated satellite water color and thermal imagery shows the extreme lower portion of the bay as a distinct water mass (due to the influx of the Fox River) with a steep gradient in water transparency and surface temperature within the first 10 km from the river mouth. Fox River water and its heavy load of suspended and adsorbed material is advectively transported up along the bays eastern shore in the form of a plume. Thus significant mixing of Fox River water is not restricted to the extreme lower portion of the bay but also is occurring in the middle portions of the bay. Similar water transparency but a distinct difference in thermal structure at the frontal zone between the Green Bay and Lake Michigan water masses indicates materials entering from the Fox River are largely retained within the bay rather than transported to the open waters of Lake Michigan.

Nature, society and history in two contrasting landscapes in Wisconsin, USA: Interactions between lakes and humans during the twentieth century

Abstract Landscapes result from the interaction between nature and society. To understand current landscapes, it is essential to disentangle this interaction; to accomplish this, an historical approach is necessary. Here we focus on the interaction between humans and lakes during the last century in two sites in Wisconsin, USA, a state where lakes, in excess of 10,000, have played an important role in the evolution of the landscapes they belong to. We draw contrasts between the two localities, which are set in landscapes that differ in their physiographic setting, environmental history, and current structure. One, in northern Wisconsin, is a forested recreational lake district; the other, in southern Wisconsin, is dominated by agricultural uses and urban and suburban development. We contend that a common development in both localities has been the increase in the value that society attaches to lakes. As a consequence, lakes are playing a bigger role in the evolution of the terrestrial landscapes surrounding them.

Detection of Spatial and Temporal Trends in Wisconsin Lake Water Clarity Using Landsat-derived Estimates of Secchi Depth

Abstract The existence of large-scale spatial and temporal trends in Wisconsins lake water clarity is a topic that has not been thoroughly investigated. This study is an effort to reliably detect these trends by utilizing three inventories of satellite-derived lake water clarity predictions for over 2,000 lakes statewide. The data were analyzed statistically on a statewide, regional, lake type, and lake area basis. Statistically significant trends in clarity were found for the state overall, as well as for particular U.S. Environmental Protection Agency Ecoregions, Wisconsin Department of Natural Resources hydrologic lake types, and lake area categories. Results will aid in the establishment of a statewide lake water clarity database and demonstrate the effectiveness of satellite-based assessments in detecting trends in water transparency over the past three decades and into the future. Documenting such trends is essential to targeting and evaluating lake management practices as well as raising public awareness of lake clarity conditions throughout the state.

Land records modernization: Centers of excellence from a Wisconsin perspective

Abstract Faculty representing a variety of disciplines at the University of Wisconsin-Madison are planning for the establishment of a center of excellence in land information science, for the purpose of providing a program that develops scholars and professionals, as recommended in a recent report of the National Research Council. They have begun by identifying an interdisciplinary graduate program focused upon education, training, and research required for the development and implementation of large-scale, multipurpose land information systems within the Public Land Survey states. These discussions have identified (a) five reasons to support the concept of centers of excellence in land information studies; (b) five components that are important, if not essential, to the development of a center; and (c) three types of resources at the University of Wisconsin-Madison, including the academic resources of seven departments, institutes, or centers offering instruction in 45 existing courses that are central to or supportive of philosophical and theoretical as well as the technical and application aspects of land records modernization; seven facilities that could provide source materials, research, and technical assistance; and three institutional cooperators. This paper reviews why centers of excellence are needed now, outlines components such a center should include, and discuss current efforts at the University of Wisconsin-Madison that support the center of excellence concept.