Physical Sciences and Mathematics Commons^™

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

Papers in Natural Resources

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 …

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

Papers in Natural Resources

No abstract provided.

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

Papers in Natural Resources

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 …

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

Papers in Natural Resources

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) …

Uncertainty In Simulating Gross Primary Production Of Cropland Ecosystem From Satellite-Based Models, Wenping Yuan, Wenwen Cai, Anthony L. Nguy-Robertson, Huajun Fang, Andrew E. Suyker, Yang Chen, Wenjie Dong, Shuguang Liu, Haicheng Zhang

Papers in Natural Resources

Accurate estimates of gross primary production (GPP) for croplands are needed to assess carbon cycle and crop yield. Satellite-based models have been developed to monitor spatial and temporal GPP patterns. However, there are still large uncertainties in estimating cropland GPP. This study compares three light use efficiency (LUE) models (MODIS-GPP, EC-LUE, and VPM) with eddy-covariance measurements at three adjacent AmeriFlux crop sites located near Mead, Nebraska, USA. These sites have different croprotation systems (continuous maize vs. maize and soybean rotated annually) and water management practices (irrigation vs. rainfed). The results reveal several major uncertainties in estimating GPP which need to …

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

Papers in Natural Resources

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(WDRVI_green), and the green band Chlorophyll Index (CI_green) 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, WDRVI_green, or CI_green). 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

Papers in Natural Resources

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 (CI_green), and the green band wide dynamic range vegetation index (WDRVI_green) 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 …

Estimation Of Crop Gross Primary Production (Gpp): FaparChl Versus Mod15a2 Fpar, Qingyuan Zhang, Yen-Ben Cheng, A. I. Lyapustin, Yujie Wang, Feng Gao, Andrew E. Suyker, Shashi B. Verma, Elizabeth M. Middleton

Papers in Natural Resources

Photosynthesis (PSN) is a pigment level process in which antenna pigments (predominately chlorophylls) in chloroplasts absorb photosynthetically active radiation (PAR) for the photochemical process. PAR absorbed by foliar non-photosynthetic components is not used for PSN. The fraction of PAR absorbed (fAPAR) by a canopy/vegetation (i.e., fAPAR_canopy) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) images, referred to as MOD15A2 FPAR, has been used to compute absorbed PAR (APAR) for PSN (APAR_PSN) which is utilized to produce the standard MODIS gross primary production (GPP) product, referred to as MOD17A2 GPP. In this study, the fraction of PAR …

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

Papers in Natural Resources

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 …

Monitoring Live Fuel Moisture Using Soil Moisture And Remote Sensing Proxies, Yi Qi, Philip E. Dennison, Jessica Spencer, David Riano

Papers in Natural Resources

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 …

Assessing Net Ecosystem Carbon Exchange Of U.S. Terrestrial Ecosystems By Integrating Eddy Covariance Flux Measurements And Satellite Observations, Jingfeng Xiao, Qianlai Zhuang, Beverly E. Law, Dennis D. Baldocchi, Jiquan Chen, Andrew D. Richardson, Jerry M. Melillo, Kenneth J. Davis, David Y. Hollinger, Sonia Wharton, Ram Oren, Asko Noormets, Marc L. Fischer, Shashi Verma, David R. Cook, Ge Sun, Steve Mcnulty, Steven C. Wofsy, Paul V. Bolstad, Sean P. Burns, Peter S. Curtis, Bert G. Drake, Matthias Falk, David R. Foster, Lianhong Gu, Julian L. Hadley, Gabriel G. Katul, Marcy Litvak, Siyan Ma, Timothy A. Martin, Roser Matamala, Tilden P. Meyers, Russell K. Monson, J. William Munger, Walter C. Oechel, U. Kyaw Tha Paw, Hans Peter Schmid, Russell L. Scott, Gregory Starr, Andrew E. Suyker, Margaret S. Torn

Papers in Natural Resources

More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr⁻¹ with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and …

A Continuous Measure Of Gross Primary Production For The Conterminous United States Derived From Modis And Ameriflux Data, Jingfeng Xiao, Qianlai Zhuang, Beverly E. Law, Jiquan Chen, Dennis D. Baldocchi, David R. Cook, Ram Oren, Andrew D. Richardson, Sonia Wharton, Siyan Ma, Timothy A. Martin, Shashi Verma, Andrew E. Suyker, Russell L. Scott, Russell K. Monson, Marcy Litvak, David Y. Hollinger, Ge Sun, Kenneth J. Davis, Paul Bolstad, Sean Burns, Peter S. Curtis, Bert G. Drake, Matthias Falk, Marc L. Fischer, David R. Foster, Lianhong Gu, Julian L. Hadley, Gabriel G. Katul, Roser Matamala, Steve Mcnulty, Tilden P. Meyers, J. William Munger, Asko Noormets, Walter Oechel, Kyaw Tha Paw U, Hans Peter Schmid, Gregory Starr, Margaret S. Torn, Steven C. Wofsy

Papers in Natural Resources

The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements of ecosystem-level exchange of carbon dioxide spanning diurnal, synoptic, seasonal, and interannual time scales. However, these measurements only represent the fluxes at the scale of the tower footprint. Here we used remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to upscale gross primary productivity (GPP) data from eddy covariance flux towers to the continental scale. We first combined GPP and MODIS data for 42 AmeriFlux towers encompassing a wide …

Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi

Papers in Natural Resources

We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the reflectance at red and …

Estimating Spatially Distributed Monthly Evapotranspiration Rates By Linear Transformations Of Modis Daytime Land Surface Temperature Data, J. Szilagyi, J. Jozsa

Papers in Natural Resources

No abstract provided.

Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley J. Moses, Anatoly A. Gitelson, V. Povazhnyy

Papers in Natural Resources

We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the …

Multi-Platform Comparisons Of Modis And Avhrr Normalized Difference Vegetation Index Data, Kevin P. Gallo, Lei Ji, Brad Reed, Jeffrey Eidenshink, John Dwyer

Papers in Natural Resources

The relationship between AVHRR-derived normalized difference vegetation index (NDVI) values and those of future sensors is critical to continued long-term monitoring of land surface properties. The follow-on operational sensor to the AVHRR, the Visible/Infrared Imager/ Radiometer Suite (VIIRS), will be very similar to the NASA Earth Observing System’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. NDVI data derived from visible and near-infrared data acquired by the MODIS (Terra and Aqua platforms) and AVHRR (NOAA-16 and NOAA-17) sensors were compared over the same time periods and a variety of land cover classes within the conterminous United States. The results indicate that the …

Regional Modis Analysis Of Abandoned Agricultural Lands In The Kazakh Steppes, Kirsten M. De Beurs, Geoffrey M. Henebry, Anatoly A. Gitelson

Papers in Natural Resources

The institutional consequences of the Soviet Union’s collapse in 1991 have been greatly underestimated as a significant forcing on the boundary layer through changes in land surface phenology. Upon independence, Kazakhstan lost the centralized agricultural planning, crop subsidy system, and access to international markets that the Soviet Union had been providing. These institutional changes led to substantial decreases in livestock populations, especially sheep, and in arable land area cultivated, especially rain-fed spring wheat in northern Kazakhstan. As a result the fallow fields reverted to weedy species and idle pastures produced denser grass cover.

In this case study we used MODIS …