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Articles 1 - 11 of 11
Full-Text Articles in Natural Resources Management and Policy
Machine Learning Algorithms Improve Modis Gpp Estimates In United States Croplands, D. Menefee, T. O. Lee, K. C. Flynn, J. Chen, M. Abraha, J. Baker, A. Suyker
Machine Learning Algorithms Improve Modis Gpp Estimates In United States Croplands, D. Menefee, T. O. Lee, K. C. Flynn, J. Chen, M. Abraha, J. Baker, A. Suyker
School of Natural Resources: Faculty Publications
No abstract provided.
Assessing Responses Of Betula Papyrifera To Climate Variability In A Remnant Population Along The Niobrara River Valley In Nebraska U.S. Through Dendroecological And Remote Sensing Techniques, Evan Bumann, Tala Awada, Brian Wardlow, Michael Hayes, Jane A. Okalebo, C. Helzer, Anastasios Mazis, J. Hiller, Paolo Cherubini
Assessing Responses Of Betula Papyrifera To Climate Variability In A Remnant Population Along The Niobrara River Valley In Nebraska U.S. Through Dendroecological And Remote Sensing Techniques, Evan Bumann, Tala Awada, Brian Wardlow, Michael Hayes, Jane A. Okalebo, C. Helzer, Anastasios Mazis, J. Hiller, Paolo Cherubini
School of Natural Resources: Faculty Publications
Remnant populations of Betula papyrifera have persisted in the Great Plains after the Wisconsin Glaciation along the Niobrara River Valley, Nebraska. Population health has declined in recent years, and has been hypothesized to be due to climate change. We used dendrochronological techniques to assess the response of B. papyrifera to microclimate (1950-2014), and satellite imagery [Landsat 5 TM (1985-2011) and MODIS (2000-2014)] derived NDVI as a proxy for population health. Growing-season streamflow and precipitation were positively correlated with raw and standardized tree-ring widths and basal area increment increase. Increasing winter and spring temperatures were unfavorable for tree growth while increasing …
A Modis Photochemical Reflectance Index (Pri) As An Estimator Of Isoprene Emissions In A Temperate Deciduous Forest, Iolanda Filella, Chao Zhang, Roger Seco, Mark Potosnak, Alex Guenther, Thomas Karl, John A. Gamon, Stephen Pallardy, Lianhong Gu, Saewung Kim, Manuela Balzarolo, Marcos Fernandez-Martinez, Josep Penuelas
A Modis Photochemical Reflectance Index (Pri) As An Estimator Of Isoprene Emissions In A Temperate Deciduous Forest, Iolanda Filella, Chao Zhang, Roger Seco, Mark Potosnak, Alex Guenther, Thomas Karl, John A. Gamon, Stephen Pallardy, Lianhong Gu, Saewung Kim, Manuela Balzarolo, Marcos Fernandez-Martinez, Josep Penuelas
School of Natural Resources: Faculty Publications
The quantification of isoprene and monoterpene emissions at the ecosystem level with available models and field measurements is not entirely satisfactory. Remote-sensing techniques can extend the spatial and temporal assessment of isoprenoid fluxes. Detecting the exchange of biogenic volatile organic compounds (BVOCs) using these techniques is, however, a very challenging goal. Recent evidence suggests that a simple remotely sensed index, the photochemical reflectance index (PRI), which is indicative of light-use efficiency, relative pigment levels and excess reducing power, is a good indirect estimator of foliar isoprenoid emissions. We tested the ability of PRI to assess isoprenoid fluxes in a temperate …
Assessing Responses Of Betula Papyrifera To Climate Variability In A Remnant Population Along The Niobrara River Valley In Nebraska, U.S.A., Through Dendroecological And Remote-Sensing Techniques, E. Bumann, T. Awada, B. Wardlow, M. Hayes, J. Okalebo, C. Helzer, A. Mazis, J. Hiller, P. Cherubini
Assessing Responses Of Betula Papyrifera To Climate Variability In A Remnant Population Along The Niobrara River Valley In Nebraska, U.S.A., Through Dendroecological And Remote-Sensing Techniques, E. Bumann, T. Awada, B. Wardlow, M. Hayes, J. Okalebo, C. Helzer, A. Mazis, J. Hiller, P. Cherubini
School of Natural Resources: Faculty Publications
No abstract provided.
Evaluation Of Modis Land Surface Temperature Data To Estimate Near-Surface Air Temperature In Northeast China, Yuan Z. Yang, Wen H. Cai, Jian Yang
Evaluation Of Modis Land Surface Temperature Data To Estimate Near-Surface Air Temperature In Northeast China, Yuan Z. Yang, Wen H. Cai, Jian Yang
Forestry and Natural Resources Faculty Publications
Air temperature (Tair) near the ground surface is a fundamental descriptor of terrestrial environment conditions and one of the most widely used climatic variables in global change studies. The main objective of this study was to explore the possibility of retrieving high-resolution Tair from the Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products, covering complex terrain in Northeast China. The All Subsets Regression (ASR) method was adopted to select the predictors and build optimal multiple linear regression models for estimating maximum (Tmax), minimum (Tmin), and mean (Tmean) air temperatures. …
Interannual Variability In Dry Mixed-Grass Prairie Yield: A Comparison Of Modis, Spot, And Field Measurements, Donald C. Wehlage, John A. Gamon, Donnette Thayer, David V. Hildebrand
Interannual Variability In Dry Mixed-Grass Prairie Yield: A Comparison Of Modis, Spot, And Field Measurements, Donald C. Wehlage, John A. Gamon, Donnette Thayer, David V. Hildebrand
School of Natural Resources: Faculty Publications
Remote sensing is often used to assess rangeland condition and biophysical parameters across large areas. In particular, the relationship between the Normalized Difference Vegetation Index (NDVI) and above-ground biomass can be used to assess rangeland primary productivity (seasonal carbon gain or above-ground biomass “yield”). We evaluated the NDVI–yield relationship for a southern Alberta prairie rangeland, using seasonal trends in NDVI and biomass during the 2009 and 2010 growing seasons, two years with contrasting rainfall regimes. The study compared harvested biomass and NDVI from field spectrometry to NDVI from three satellite platforms: the Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) …
Estimation Of Crop Gross Primary Production (Gpp): Ii. Do Scaledmodis Vegetation Indices Improve Performance?, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiaoyang Zhang, Andrew E. Suyker, Shashi Verma, Yanmin Shuai, Elizabeth M. Middleton
Estimation Of Crop Gross Primary Production (Gpp): Ii. Do Scaledmodis Vegetation Indices Improve Performance?, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiaoyang Zhang, Andrew E. Suyker, Shashi Verma, Yanmin Shuai, Elizabeth M. Middleton
School of Natural Resources: Faculty Publications
Satellite remote sensing estimates of gross primary production (GPP) have routinely been made using spectral vegetation indices (VIs) over the past two decades. The Normalized Difference Vegetation Index(NDVI), the Enhanced Vegetation Index (EVI), the green band Wide Dynamic Range Vegetation Index(WDRVIgreen), and the green band Chlorophyll Index (CIgreen) have been employed to estimate GPP under the assumption that GPP is proportional to the product of VI and photosynthetically active radiation (PAR)(where VI is one of four VIs: NDVI, EVI, WDRVIgreen, or CIgreen). However, the empirical regressions between VI*PAR and GPP measured locally …
Estimation Of Crop Gross Primary Production (Gpp): I. Impact Of Modisobservation Footprint And Impact Of Vegetation Brdf Characteristics, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiangming Xiao, Andrew E. Suyker, Shashi Verma, Bin Tan, Elizabeth M. Middleton
Estimation Of Crop Gross Primary Production (Gpp): I. Impact Of Modisobservation Footprint And Impact Of Vegetation Brdf Characteristics, Qingyuan Zhang, Yen-Ben Cheng, Alexei I. Lyapustin, Yujie Wang, Xiangming Xiao, Andrew E. Suyker, Shashi Verma, Bin Tan, Elizabeth M. Middleton
School of Natural Resources: Faculty Publications
Accurate estimation of gross primary production (GPP) is essential for carbon cycle and climate change studies. Three AmeriFlux crop sites of maize and soybean were selected for this study. Two of the sites were irrigated and the other one was rainfed. The normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), the green band chlorophyll index (CIgreen), and the green band wide dynamic range vegetation index (WDRVIgreen) were computed from the moderate resolution imaging spectroradiometer (MODIS) surface reflectance data. We examined the impacts of the MODIS observation footprint and the vegetation bidirectional reflectance distribution function …
Monitoring Live Fuel Moisture Using Soil Moisture And Remote Sensing Proxies, Yi Qi, Philip E. Dennison, Jessica Spencer, David Riano
Monitoring Live Fuel Moisture Using Soil Moisture And Remote Sensing Proxies, Yi Qi, Philip E. Dennison, Jessica Spencer, David Riano
School of Natural Resources: Faculty Publications
Live fuel moisture (LFM) is an important fuel property controlling fuel ignition and fire propagation. LFM varies seasonally, and is controlled by precipitation, soil moisture, evapotranspiration, and plant physiology. LFM is typically sampled manually in the field, which leads to sparse measurements in space and time. Use of LFM proxies could reduce the need for field sampling while potentially improving spatial and temporal sampling density. This study compares soil moisture and remote sensing data to field-sampled LFM for Gambel oak (Quercus gambelii Nutt) and big sagebrush (Artemisia tridentata Nutt) in northern Utah. Bivariate linear regression models were constructed …
An Alternative Method Using Digital Cameras For Continuous Monitoring Of Crop Status, Toshihiro Sakamoto, Anatoly A. Gitelson, Anthony L. Nguy-Robertson, Timothy J. Arkebauer, Brian D. Wardlow, Andrew E. Suyker, Shashi B. Verma, Michio Shibayama
An Alternative Method Using Digital Cameras For Continuous Monitoring Of Crop Status, Toshihiro Sakamoto, Anatoly A. Gitelson, Anthony L. Nguy-Robertson, Timothy J. Arkebauer, Brian D. Wardlow, Andrew E. Suyker, Shashi B. Verma, Michio Shibayama
School of Natural Resources: Faculty Publications
Crop physiological and phenological status is an important factor that characterizes crop yield as well as carbon exchange between the atmosphere and the terrestrial biosphere in agroecosystems. It is difficult to establish high frequency observations of crop status in multiple locations using conventional approaches such as agronomical sampling and also remote sensing techniques that use spectral radiometers because of the labor intensive work required for field surveys and the high cost of radiometers designed for scientific use. This study explored the potential utility of an inexpensive camera observation system called crop phenology recording system (CPRS) as an alternative approach for …
Estimating Spatially Distributed Monthly Evapotranspiration Rates By Linear Transformations Of Modis Daytime Land Surface Temperature Data, J. Szilagyi, J. Jozsa
Estimating Spatially Distributed Monthly Evapotranspiration Rates By Linear Transformations Of Modis Daytime Land Surface Temperature Data, J. Szilagyi, J. Jozsa
School of Natural Resources: Faculty Publications
No abstract provided.