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Full-Text Articles in Geography
Trends In Land Surface Phenology Across The Conterminous United States (1982-2016) Analyzed By Neon Domains, Liang Liang, Geoffrey M. Henebry, Lingling Liu, Xiaoyang Zhang, Li-Chih Hsu
Trends In Land Surface Phenology Across The Conterminous United States (1982-2016) Analyzed By Neon Domains, Liang Liang, Geoffrey M. Henebry, Lingling Liu, Xiaoyang Zhang, Li-Chih Hsu
Geography Faculty Publications
Tracking phenological change in a regionally explicit context is a key to understanding ecosystem status and change. The current study investigated long-term trends of satellite-observed land surface phenology (LSP) in the 17 National Ecological Observatory Network (NEON) domains across the conterminous United States (CONUS). Characterization of LSP trends was based on a high temporal resolution (3-d) time series of the two-band enhanced vegetation index (EVI2) derived from a long-term data record (LTDR) of the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS). We identified significant trend patterns in LSP and their seasonal climate and land …
Detecting Recent Crop Phenology Dynamics In Corn And Soybean Cropping Systems Of Kentucky, Yanjun Yang, Bo Tao, Liang Liang, Yawen Huang, Christopher J. Matocha, Chad D. Lee, Michael Sama, Bassil El Masri, Wei Ren
Detecting Recent Crop Phenology Dynamics In Corn And Soybean Cropping Systems Of Kentucky, Yanjun Yang, Bo Tao, Liang Liang, Yawen Huang, Christopher J. Matocha, Chad D. Lee, Michael Sama, Bassil El Masri, Wei Ren
Geography Faculty Publications
Accurate phenological information is essential for monitoring crop development, predicting crop yield, and enhancing resilience to cope with climate change. This study employed a curve-change-based dynamic threshold approach on NDVI (Normalized Differential Vegetation Index) time series to detect the planting and harvesting dates for corn and soybean in Kentucky, a typical climatic transition zone, from 2000 to 2018. We compared satellite-based estimates with ground observations and performed trend analyses of crop phenological stages over the study period to analyze their relationships with climate change and crop yields. Our results showed that corn and soybean planting dates were delayed by 0.01 …
Rock Glaciers Of The Beartooth And Northern Absaroka Ranges, Montana, Usa, Zachary M. Seligman, Anna E. Klene, Frederick E. Nelson
Rock Glaciers Of The Beartooth And Northern Absaroka Ranges, Montana, Usa, Zachary M. Seligman, Anna E. Klene, Frederick E. Nelson
Geography Faculty Publications
Six hundred sixty‐one rock glaciers in the northern Absaroka and Beartooth Ranges of south‐central Montana were digitized and evaluated using geographic information systems technology and an array of topographic and environmental parameters. Beartooth rock glaciers are larger, occur at higher elevations, receive more precipitation, and are subject to lower temperatures than northern Absaroka rock glaciers. Elevation is strongly correlated with rock glacier activity. Comparative analysis of these adjacent mountain ranges indicates that Beartooth geomorphic landscapes are shifting from predominantly glacial to periglacial regimes, and that the northern Absarokas have largely completed this transition. Because glaciers are declining in response to …
Mapping Temperate Vegetation Climate Adaptation Variability Using Normalized Land Surface Phenology, Liang Liang, Mark D. Schwartz, Xiaoyang Zhang
Mapping Temperate Vegetation Climate Adaptation Variability Using Normalized Land Surface Phenology, Liang Liang, Mark D. Schwartz, Xiaoyang Zhang
Geography Faculty Publications
Climate influences geographic differences of vegetation phenology through both contemporary and historical variability. The latter effect is embodied in vegetation heterogeneity underlain by spatially varied genotype and species compositions tied to climatic adaptation. Such long-term climatic effects are difficult to map and therefore often neglected in evaluating spatially explicit phenological responses to climate change. In this study we demonstrate a way to indirectly infer the portion of land surface phenology variation that is potentially contributed by underlying genotypic differences across space. The method undertaken normalized remotely sensed vegetation start-of-season (or greenup onset) with a cloned plants-based phenological model. As the …
Networks Of European Cities In Worlds Of Global Economic And Environmental Change, Stanley D. Brunn, Lomme Devriendt, Andrew Boulton, Ben Derudder, Frank Witlox
Networks Of European Cities In Worlds Of Global Economic And Environmental Change, Stanley D. Brunn, Lomme Devriendt, Andrew Boulton, Ben Derudder, Frank Witlox
Geography Faculty Publications
Geographers have a long tradition of classifying cities using a number of criteria. Population size, industrial production, capital city functions, airline connections, sites of sporting events and major headquarters and banks are among them. While these studies are useful in looking at cities in an economy and population at a given point of time, they are less useful in assessing rapidly occurring changes within a regional or global system. Our research represents a new approach to classify cities and urban systems; we use the volume and networks/linkages or flows associated with electronic Information or “Knowledge worlds.” We argue that in …