Physical and Environmental Geography Commons^™

Precipitation Intensity Trend Detection Using Hourly And Daily Observations In Portland, Oregon, Alexis Cooley, Heejun Chang

Geography Faculty Publications and Presentations

The intensity of precipitation is expected to increase in response to climate change, but the regions where this may occur are unclear. The lack of certainty from climate models warrants an examination of trends in observational records. However, the temporal resolution of records may affect the success of trend detection. Daily observations are often used, but may be too coarse to detect changes. Sub-daily records may improve detection, but their value is not yet quantified. Using daily and hourly records from 24 rain gages in Portland, Oregon (OR), trends in precipitation intensity and volume are examined for the period of …

The Cost Of Hauling Timber: A Comparison Of Raster- And Vector- Based Travel-Time Estimates In Gis, Sara M. Loreno

Geography Masters Research Papers

The cost of transporting forest products from harvest site to processing facility is a critical indicator of timber project feasibility. In order to accurately assess these timber haul costs, least-cost travel-time estimates among the site and the facility can be estimated using vector- or raster-based GIS methods. This study explores the applicability of both the raster- and vector-techniques within a variety of landscapes, including forested areas where comprehensive transportation data is limited. A comparison between the travel-time estimates derived from both methods was performed on three study sites using real-world data. The comparison also tested the effect of resolution on …

Western Juniper (Juniperus Occidentalis) Ecology With An Exercise In Remote Sensing Techniques, Elizabeth A. Goralski

Geography Masters Research Papers

Western juniper (Juniperus occidentalis var. occidentalis) has been expanding its biogeographic range since the mid-1800's, resulting in decreased biodiversity, altered wildlife habitat, increased soil erosion, reduced stream flows and reduced forage production. The direct causes of western juniper aforestation are unclear but appear to be related to altered fire regimes, over grazing, and climatic shifts.

This study seeks to determine how Landsat images combined with Digital Orthoquads (DOQs) can be used to examine the geographic distribution of western juniper. Satellite imagery has yet to be applied to the large scale mapping of western juniper aforestation, resulting in the lack of …

Methods For Correcting Topographically Induced Radiometric Distortion On Landsat Thematic Mapper Images For Land Cover Classification, David Michael Rosen

Geography Masters Research Papers

Satellite imagery is commonly used to study land-use, land-cover change in mountainous areas. Classification of land-cover types is particularly difficult in this type of terrain because topography affects the spectral response of surface features. Several techniques have been developed to help compensate for this topographic effect and to increase classification accuracy.

The purpose of this study is to compare topographic correction methods to determine which produces the most accurate results. Method 1 does not use any topographic correction, serving as a control. Method 2 is based on the Lambertian model, and uses topographical data as variables in an equation. Method …

Comparing Twenty-Four Years Of Forest Change In Two Communities Of Mexico's Meseta PuréPecha Using Multi-Spectral Satellite Imagery, Kevin Scott Martin

Dissertations and Theses

The Meseta Purépecha, a volcanic plateau in the Mexican state of Michoacan, is home to one of the most species-rich pine forests in the world. Recent increases in demand for forest products has put added pressure on these resources. Though existing research has suggested significant deforestation in the Meseta, there is little information identifying specific areas of decline. This study focuses on two indigenous communities in the Meseta--Pichátaro and Sevina. Both communities have long relied on wood as an economic resource. However, the two communities have reacted differently to increased demand for forest resources. The purpose of this study is …