Open Access. Powered by Scholars. Published by Universities.®

Physical and Environmental Geography Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 13 of 13

Full-Text Articles in Physical and Environmental Geography

Sequias En El Sur De La Peninsula De Yucatan: Analisis De La Variabilidad Anual Y Estacional De La Precipitacion (Droughts In The Southern Yucatan Peninsula: Analysis Of The Annual And Seasonal Precipitation Variability), Sofia Mardero, Elsa Nickl, Birgit Schmook, Laura Schneider, John Rogan, Zachary Christman, Deborah Lawrence Dec 2016

Sequias En El Sur De La Peninsula De Yucatan: Analisis De La Variabilidad Anual Y Estacional De La Precipitacion (Droughts In The Southern Yucatan Peninsula: Analysis Of The Annual And Seasonal Precipitation Variability), Sofia Mardero, Elsa Nickl, Birgit Schmook, Laura Schneider, John Rogan, Zachary Christman, Deborah Lawrence

Zachary Christman

Paper is in Spanish. English abstract: This study analyzes the spatial and temporal variability of precipitation across the Southern Yucatán Peninsula in Mexico, addressing the anomalies and trends of annual and seasonal precipitation as well as the occurrence of meteorological droughts, using rainfall data from nine weather stations during the period 1953-2007. Linear regression in the annual and seasonal rainfall were used to analyze the increase or decrease in precipitation trends over this period. Precipitation anomalies enabled the evaluation of the stability, deficit, or surplus of precipitation for each year or season, and a quintile method was used to …


Prototype For Monitoring And Forecasting Fall Foliage Coloration In Real Time From Satellite Data, Xiaoyang Zhang, Mitchell D. Goldberg, Yunyue Yu Sep 2016

Prototype For Monitoring And Forecasting Fall Foliage Coloration In Real Time From Satellite Data, Xiaoyang Zhang, Mitchell D. Goldberg, Yunyue Yu

Xiaoyang Zhang

While determining vegetation phenology from the time series of historical satellite data has been widely investigated throughout the last decade, little effort has been devoted to real-time monitoring and short-term forecasting. The latter is more important for numerical weather modeling, ecosystem forecasting, forest and crop management, and health risk warning. In this study we developed a prototype approach for the real-time monitoring and short-term forecasting of fall foliage status (including low coloration, moderate coloration, near-peak coloration, peak coloration, and post-peak coloration) using temporal satellite observations. The algorithm combined the climatology of vegetation phenology and temporally available satellite observations to establish …


Interannual Variations And Trends In Global Land Surface Phenology Derived From Enhanced Vegetation Index During 1982–2010, Xiaoyang Zhang, Bin Tan, Yunyue Yu Sep 2016

Interannual Variations And Trends In Global Land Surface Phenology Derived From Enhanced Vegetation Index During 1982–2010, Xiaoyang Zhang, Bin Tan, Yunyue Yu

Xiaoyang Zhang

Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel …


Daily Modis 500 M Reflectance Anisotropy Direct Broadcast (Db) Products For Monitoring Vegetation Phenology Dynamics, Yanmin Shuai, Crystal Schaaf, Xiaoyang Zhang, Alan Strahler, David P. Roy, Jeffery Morisette, Zhuosen Wang, Joanne Nightingale, Jaime Nickerson, Andrew D. Richardson, Donghui Xie, Jindi Wang, Xiaowen Li, Kathleen Strabala, James E. Davies Sep 2016

Daily Modis 500 M Reflectance Anisotropy Direct Broadcast (Db) Products For Monitoring Vegetation Phenology Dynamics, Yanmin Shuai, Crystal Schaaf, Xiaoyang Zhang, Alan Strahler, David P. Roy, Jeffery Morisette, Zhuosen Wang, Joanne Nightingale, Jaime Nickerson, Andrew D. Richardson, Donghui Xie, Jindi Wang, Xiaowen Li, Kathleen Strabala, James E. Davies

Xiaoyang Zhang

Land surface vegetation phenology is an efficient bio-indicator for monitoring ecosystem variation in response to changes in climatic factors. The primary objective of the current article is to examine the utility of the daily MODIS 500 m reflectance anisotropy direct broadcast (DB) product for monitoring the evolution of vegetation phenological trends over selected crop, orchard, and forest regions. Although numerous model-fitted satellite data have been widely used to assess the spatio-temporal distribution of land surface phenological patterns to understand phenological process and phenomena, current efforts to investigate the details of phenological trends, especially for natural phenological variations that occur on …


A Cross Comparison Of Spatiotemporally Enhanced Springtime Phenological Measurements From Satellites And Ground In A Northern U.S. Mixed Forest, Liang Liang, Mark D. Schwartz, Zhuosen Wang, Feng Gao, Crystal B. Schaaf, Bin Tan, Jeffrey T. Morisette, Xiaoyang Zhang Sep 2016

A Cross Comparison Of Spatiotemporally Enhanced Springtime Phenological Measurements From Satellites And Ground In A Northern U.S. Mixed Forest, Liang Liang, Mark D. Schwartz, Zhuosen Wang, Feng Gao, Crystal B. Schaaf, Bin Tan, Jeffrey T. Morisette, Xiaoyang Zhang

Xiaoyang Zhang

Cross comparison of satellite-derived land surface phenology (LSP) and ground measurements is useful to ensure the relevance of detected seasonal vegetation change to the underlying biophysical processes. While standard 16-day and 250-m Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation index (VI)-based springtime LSP has been evaluated in previous studies, it remains unclear whether LSP with enhanced temporal and spatial resolutions can capture additional details of ground phenology. In this paper, we compared LSP derived from 500-m daily MODIS and 30-m MODIS-Landsat fused VI data with landscape phenology (LP) in a northern U.S. mixed forest. LP was previously developed from intensively observed …


Bringing Football Back To Los Angeles, Gabriel Leiner Jul 2015

Bringing Football Back To Los Angeles, Gabriel Leiner

Gabriel Leiner

Identifying a suitable parcel for a large scale professional football stadium in the greater Los Angeles, CA area, which does not conflict with current uses, environmental protection codes, or airspace rights, and also has adequate transportation access and nearby populated neighborhoods.


Socio-Environmental Considerations At The Usuma Reservoir In Abuja, Nigeria, Fanan Ujoh Mr, James Ikyernum Mr, Olarewaju O. Ifatimehin Dr Dec 2012

Socio-Environmental Considerations At The Usuma Reservoir In Abuja, Nigeria, Fanan Ujoh Mr, James Ikyernum Mr, Olarewaju O. Ifatimehin Dr

Dr. Fanan Ujoh

Reservoirs are Man’s attempt towards water re-distribution from regions/seasons of abundance/surplus to regions/seasons of scarcity. This study focuses on socio-environmental impacts of the Lower Usuma dam in Abuja, on its four surrounding communities. Stratified random sampling technique was employed in the administration of a questionnaire to 200 respondents. Using descriptive statistics and the student t-test for the analysis, the study discovered that: (i) there has been no significant improvement in infrastructure provision by Government; (ii) cases of water-borne diseases are high; (iii) the communities have lost land for cultivation; and, (iv) the communities believe that the resettlement scheme is not …


Geomorphic Determinants Of Species Composition Of Alpine Tundra, Glacier National Park, U.S.A., George P. Malanson Dec 2011

Geomorphic Determinants Of Species Composition Of Alpine Tundra, Glacier National Park, U.S.A., George P. Malanson

George P Malanson

Because the distribution of alpine tundra is associated with spatially limited cold climates, global warming may threaten its local extent or existence. This notion has been challenged, however, based on observations of the diversity of alpine tundra in small areas primarily due to topographic variation. The importance of diversity in temperature or moisture conditions caused by topographic variation is an open question, and we extend this to geomorphology more generally. The extent to which geomorphic variation per se, based on relatively easily assessed indicators, can account for the variation in alpine tundra community composition is analyzed versus the inclusion of …


Mountain Treelines: A Roadmap For Research Orientation, George P. Malanson Dec 2010

Mountain Treelines: A Roadmap For Research Orientation, George P. Malanson

George P Malanson

For over 100 years, mountain treelines have been the subject of varied research endeavors and remain a strong area of investigation. The purpose of this paper is to examine aspects of the epistemology of mountain treeline research—that is, to investigate how knowledge on treelines has been acquired and the changes in knowledge acquisition over time, through a review of fundamental questions and approaches. The questions treeline researchers have raised and continue to raise have undoubtedly directed the current state of knowledge. A continuing, fundamental emphasis has centered on seeking the general cause of mountain treelines, thus seeking an answer to …


Anthropogenic Landform Modeling Using Gis Techniques Case Study: Vrancea Region, Adrian Ursu, Dan A. Chelaru, Florin C. Mihai Dec 2010

Anthropogenic Landform Modeling Using Gis Techniques Case Study: Vrancea Region, Adrian Ursu, Dan A. Chelaru, Florin C. Mihai

Florin C MIHAI

Anthropogenic landforms are the result of significant changes in the Earth's crust due to technological development of human society, guided by its economic, social and cultural needs. nthropogenic landforms of the studied area was analyzed using GIS techniques at the general scale, conducting the entire study area maps, and detailed modeling of representative samples in detail. Representing the anthropogenic landforms on the digital elevation model can be very important in studying natural hazards, such as hydrological modeling on flood plains, which could influence the direction of the flood wave. The digital elevation model (DEM) made by traditional methods can not …


An Analysis Of Temperature Variations Using Remote Sensing Approach In Lokoja Area, Fanan Ujoh Mr, Olarewaju O. Ifatimehin Mr, Sunday Ishaya Mr Jan 2010

An Analysis Of Temperature Variations Using Remote Sensing Approach In Lokoja Area, Fanan Ujoh Mr, Olarewaju O. Ifatimehin Mr, Sunday Ishaya Mr

Dr. Fanan Ujoh

This study investigates the thermal variations of the different land use/cover types in urban Lokoja town retrieved from Landsat TM imagery of 1987. Band 2, 3, 4 and 6 of the imagery were used in the classification, estimation of NDVI, land surface emissivity values, and satellite sensor temperature. The Qin et al’s mono window algorithm was employed to obtain the land surface temperatures of the different land use/cover types classified. The results indicate that there is a significant variation in temperatures among the different land use/cover types in Lokoja. The built up area and the vacant area have the highest …


A Plotless Density Estimator Based On The Asymptotic Limit Of Ordered Distance Estimation Values, Barry J. Kronenfeld Jan 2009

A Plotless Density Estimator Based On The Asymptotic Limit Of Ordered Distance Estimation Values, Barry J. Kronenfeld

Barry J. Kronenfeld

Estimation of tree density from point-tree distances is an attractive option for quick inventory of new sites, but estimators that are unbiased in clustered and dispersed situations have not been found. Noting that bias of an estimator derived from distances to the kth nearest neighbor from a random point tends to decrease with increasing k, a method is proposed for estimating the limit of an asymptotic function through a set of ordered distance estimators. A standard asymptotic model is derived from the limiting case of a clustered distribution. The proposed estimator is evaluated against 13 types of simulated generating processes, …


An Evaluation Of The Effect Of Land Use/Cover Change On The Surface Temperature Of Lokoja Town, Nigeria, Fanan Ujoh Mr, Olarewaju O. Ifatimehin Mr, John Y. Magaji Dr Jan 2009

An Evaluation Of The Effect Of Land Use/Cover Change On The Surface Temperature Of Lokoja Town, Nigeria, Fanan Ujoh Mr, Olarewaju O. Ifatimehin Mr, John Y. Magaji Dr

Dr. Fanan Ujoh

This research integrated remote sensing and Geographic Information Systems (GIS) to identified land use/cover types in Lokoja, including their temporal transformation and association with surface temperatures from the LandSat TM and LandSat ETM imageries of 1987 and 2001 respectively. As the built-up area increased in size (2667.6%) so was the surface temperature (6.48oC), vacant land (872%: 9.65oC), cultivated land (104.4%: 1.2oC) and water bodies (64.3%:0.94oC) while vegetation cover increased by 2.44oC while its area extent decreased (316.7%). These changes were responsible for the rise in the mean surface temperature from 38.39oC in 1987 to 42.61oC in 2001, indicating a 4.22oC …