Other Environmental Sciences Commons^™

Unraveling Crop Nitrogen-Water Dynamics With Hyperspectral-Thermal Sensing In Northern Central Valley, California, Shahryar Fazli, Surendra Maharjan, Wenzhao Li, Joshua B. Fisher, Rejoice Thomas, Fernando Romero Galvan, Gabriela Shirkey, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Ensuring global food security in the face of climate change requires optimizing crop water use and nutrient management. This study investigates the relationship between canopy nitrogen (N) and evapotranspiration (ET) across sunflower, rice, walnut, alfalfa, and plum crops using advanced remote sensing technologies. High-resolution hyperspectral data from NASAs Earth Surface Mineral Dust Source Investigation (EMIT) and thermal multispectral data from the Landsat-based OpenET system were analyzed over 1,135 km² in California. Regression analysis revealed strong spatial association between canopy N and ET for sunflower (R² = 0.82), rice (R² = 0.71), and walnut (R² = 0.68), …

The Flash Droughts Across The South-Central United States In 2022: Drivers, Predictability, And Impacts, J. I. Christian, T. M. Grace, B. J. Fellman, D. F. Meshaske, S. G. Edris, H. O. Olayiwola, J. B. Basara, Brian Fuchs, J. C. Furtado

School of Natural Resources: Faculty Publications

No abstract provided.

Multivariate Evaluation Of Flash Drought Across The United States, J. A. Otkin, Y. Zhong, T. W. Ford, M. C. Anderson, C. Hain, A. Hoell, Mark D. Svoboda, H. Wang

School of Natural Resources: Faculty Publications

No abstract provided.

A Comparative Analysis Of Openet For Evaluating Evapotranspiration In California Almond Orchards, K. Knipper, M. Anderson, N. Bambach, F. Melton, Z. Ellis, Y. Yang, J. Volk, A. J. Mcelrone, W. Kustas, M. Roby, W. Carrara, S. Castro, Ayse Kilic

School of Natural Resources: Faculty Publications

No abstract provided.

Understanding The Soil Water Dynamics During Excess And Deficit Rainfall Conditions Over The Core Monsoon Zone Of India, Mangesh M. Goswami, Milind Mujumdar1, Bhupendra Bahadur Singh, Madhusudan Ingale, Naresh Ganeshi, Manish Ranalkar, Trenton E. Franz, Prashant Srivastav, Dev Niyogi, R Krishnan, S N. Patil

School of Natural Resources: Faculty Publications

Observations of soil moisture (SM) during excess and deficit monsoon seasons between 2000 to 2021 present a unique opportunity to understand the soil water dynamics (SWD) over core monsoon zone (CMZ) of India. This study aims to analyse SWD by investigating the SM variability, SM memory (SMM), and the coupling between surface and subsurface SM levels. Particularly intriguing are instances of concurrent monsoonal extremes, which give rise to complex SWD patterns. Usually, it is noted that a depleted convective activity and persistence of higher temperatures during the pre-monsoon season leads to lower SM, while monsoon rains and post-monsoon showers support …

Development Of A Benchmark Eddy Flux Evapotranspiration Dataset For Evaluation Of Satellite-Driven Evapotranspiration Models Over The Conus, John M. Volk, Justin Huntington, Forrest S. Melton, Richard Allen, Martha C. Anderson, Joshua B. Fisher, Ayse Kilic, Gabriel Senay, Gregory Halverson, Kyla Knipper, Blake Minor, Christopher Pearson, Tianxin Wang, Yun Yang, Steven Evett, Andrew N. French, Richard Jasoni, William Kustas

School of Natural Resources: Faculty Publications

A large sample of ground-based evapotranspiration (ET) measurements made in the United States, primarily from eddy covariance systems, were post-processed to produce a benchmark ET dataset. The dataset was produced primarily to support the intercomparison and evaluation of the OpenET satellite-based remote sensing ET (RSET) models and could also be used to evaluate ET data from other models and approaches. OpenET is a web-based service that makes field-delineated and pixel-level ET estimates from well-established RSET models readily available to water managers, agricultural producers, and the public. The benchmark dataset is composed of flux and meteorological data from a variety of …

Assessment Of An Evapotranspiration Algorithm Accounting For Land Cover Types And Photosynthetic Perspectives Using Remote Sensing Images, C. Sur, W. H. Nam, X. Zhang, Tsegaye Tadesse, Brian D. Wardlow

School of Natural Resources: Faculty Publications

No abstract provided.

Empirical Fitting Of Periodically Repeating Environmental Data, Pavel Bělík, Andrew Hotchkiss, Brandon Perez, John Zobitz

Spora: A Journal of Biomathematics

We extend and generalize an approach to conduct fitting models of periodically repeating data. Our method first detrends the data from a baseline function and then fits the data to a periodic (trigonometric, polynomial, or piecewise linear) function. The polynomial and piecewise linear functions are developed from assumptions of continuity and differentiability across each time period. We apply this approach to different datasets in the environmental sciences in addition to a synthetic dataset. Overall the polynomial and piecewise linear approaches developed here performed as good (or better) compared to the trigonometric approach when evaluated using statistical measures (R^{2 …}

Calibration-Free Complementary Relationship Estimates Terrestrial Evapotranspiration Globally, N. Ma, J. Szilagyi, Y. Zhang

School of Natural Resources: Faculty Publications

No abstract provided.

Connections Between The Hydrological Cycle And Crop Yield In The Rainfed U.S. Corn Belt, Wang Zhou, Kaiyu Guan, Bin Peng, Jiancheng Shi, Chongya Jiang, Brian Wardlow, Ming Pan, John S. Kimball, Trenton Franz, Pierre Gentine, Mingzhu He, Jingwen Zhang

School of Natural Resources: Faculty Publications

No abstract provided.

Water Balance Backward: Estimation Of Annual Watershed Precipitation And Its Long-Term Trend With The Help Of The Calibration-Free Generalized Complementary Relationship Of Evaporation, J. Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Current Frameworks For Reference Et And Crop Coefficient Calculation, R G. Allen, Ayse Kilic, Clarence W. Robison

School of Natural Resources: Faculty Publications

Estimation of evapotranspiration is under continual development and evolution, with significant developments and standardizations made during the past three decades for both reference ET (ETref) and for crop coefficients (Kc). These standardizations provide consistency and reproducibility in estimating ETref and a consistent basis for determining and expressing Kc curves, especially at the local scale. The application of the dual Kc procedure is growing, and has strong potential for improving accuracy of ET estimates as compared to the single Kc approach. This article describes current structures for estimating crop coefficients including the standardized FAO-56 dual Kc approach, with example applications. Emphasis …

Applying The Fao-56 Dual KC Method For Irrigation Water Requirements Over Large Areas Of The Western U.S., Richard Allen, Clarence W. Robison, Justin Huntington, James L. Wright, Ayse Kilic

School of Natural Resources: Faculty Publications

The FAO-56 dual crop coefficient procedure was used to determine evapotranspiration (ET) and net irrigation water requirements for all agricultural areas of the states of Idaho and Nevada and in a western U.S. study on effects of climate change on future irrigation water requirements. The products of the applications are for use by state governments for water rights management, irrigation system planning and design, wastewater application system design and review, hydrologic water balances, and groundwater modeling. The products have been used by the U.S. federal government for assessing impacts of current and future climate change on irrigation water demands. The …

A Review Of Landscape Water Requirements Using A Multicomponent Landscape Coefficient, R G. Allen, M. D. Dukes, R. L. Snyder, R. Kjelgren, Ayse Kilic

School of Natural Resources: Faculty Publications

Water requirements of landscapes are highly variable due to the heterogeneous natures of landscapes, vegetation types, influence of buildings, and nutrient and water management. Objectives for water management of landscapes are for general appearance and health rather than for maximum biomass production. A multi-component method developed for the Irrigation Association (IA) and extended from the California WUCOLS procedure is demonstrated in which the landscape coefficient (KL, equivalent to a crop coefficient) is broken down into four components: vegetation type, vegetation density, microclimate, and managed stress. Each of these components can be estimated using readily made descriptions of a landscaped area …

Global Production And Free Access To Landsat-Scale Evapotranspiration With Eeflux And Eemetric, Ayse Kilic, R G. Allen, Philip A. Blankenau, Peter Revelle, Doruk Ozturk, Justin L. Huntington

School of Natural Resources: Faculty Publications

EEFlux (Earth Engine Evapotranspiration Flux) is a version of the METRIC (mapping evapotranspiration at high resolution with internal calibration) application that operates on the Google Earth Engine (EE). EEFlux has a web-based interface and provides free public access to transform Landsat images into 30 m spatial evapotranspiration (ET) data for terrestrial land areas around the globe. EE holds the entire Landsat archive to power EEFlux along with NLDAS/CFSV2 gridded weather data for estimating reference ET. EEFlux is a part of the upcoming OpenET platform (https://openetdata.org/ ) that has leveraged nonprofit funding to provide ET information to all of the lower …

Metric-Gis: An Advanced Energy Balance Model For Computing Crop Evapotranspiration In A Gis Environment, J. M. Ramírez-Cuesta, R G. Allen, D. S. Intrigliolo, Ayse Kilic, Clarence W. Robison, Ricardo Trezza, C. Santos, I. J. Lorite

School of Natural Resources: Faculty Publications

A novel ArcGIS toolbox that applies the Mapping Evapotranspiration with Internalized Calibration model was developed and tested in a semi-arid environment. The tool, named METRIC-GIS, facilitates the pre-processing operations and the automatic identification of potential calibration and pixels review. The energy balance components obtained from METRIC-GIS were contrasted with those from the original METRIC version (R² = 1; RMSE = 0 W m^–2 or mm day^–1 for ET_c) Additionally, an irrigated scheme located at southern Spain was considered for assessing Kc variability in the maize fields with METRIC-GIS. The identified spatial variability was mainly due …

Annual, Seasonal, And Diel Surface Energy Partitioning In The Semiarid Sand Hills Of Nebraska, Usa, Nathan C. Healey, Timothy J. Arkebauer, David P. Billesbach, John D. Lenters

School of Natural Resources: Faculty Publications

Study Region: The Nebraska Sand Hills consisting of four major land cover types: (1) lakes and wetlands (∼5% for both), (2) subirrigated meadows (∼10%), (3) dry valleys (∼20%), and (4) upland dunes (∼65%).

Study Focus: Examination of surface energy and water balances on multiple temporal scales with primary focus on latent heat flux (λE), and evapotranspiration (ET), to gain a better understanding of the annual, seasonal, and diel properties of surface energy partitioning among different Sand Hills ecosystems to improve regional water resource management. New Hydrological Insights for the Region: Based on surface energy and water balance measurements using Bowen …

Evapotranspiration Trends (1979-2015) In The Central Valley Of California, Usa: Contrasting Tendencies During 1981-2007, Jozsef Szilagyi, Janos Jozsa

School of Natural Resources: Faculty Publications

No abstract provided.

A Calibration-Free, Robust Estimation Of Monthly Land Surface Evapotranspiration Rates For Continental-Scale Hydrology, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Feasibility Analysis Of Using Inverse Modeling For Estimating Field-Scale Evapotranspiration In Maize And Soybean Fields From Soil Water Content Monitoring Networks, Foad Foolad, Trenton E. Franz, Tiejun Wang, Justin Gibson, Ayse Kilic, Richard Allen, Andrew Suyker

School of Natural Resources: Faculty Publications

No abstract provided.

Estimation Of Energy Balance Components Over A Drip-Irrigated Olive Orchard Using Thermal And Multispectral Cameras Placed On A Helicopter-Based Unmanned Aerial Vehicle (Uav), Samuel Ortega-Farias, Samuel Ortega-Salazar, Tomas Poblete, Ayse Kilic, Richard Allen, Carlos Poblete-Echeverria, Luis Ahumada-Orellana, Mauricio Zuniga, Daniel Sepulveda

School of Natural Resources: Faculty Publications

A field experiment was carried out to implement a remote sensing energy balance (RSEB) algorithm for estimating the incoming solar radiation (Rsi), net radiation (Rn), sensible heat flux (H), soil heat flux (G) and latent heat flux (LE) over a drip-irrigated olive (cv. Arbequina) orchard located in the Pencahue Valley, Maule Region, Chile (35^◦25'S; 71^◦44'W; 90 m above sea level). For this study, a helicopter-based unmanned aerial vehicle (UAV) was equipped with multispectral and infrared thermal cameras to obtain simultaneously the normalized difference vegetation index (NDVI) and surface temperature (Tsurface) at very high resolution (6 cm …

Eeflux: A Landsat-Based Evapotranspiration Mapping Tool On The Google Earth Engine, Richard Allen, Charles Morton, Baburao Kamble, Ayse Kilic, Justin Huntington, David Thau, Noel Gorelick, Tyler Erickson, Rebecca Moore, Ricardo Trezza, Ian C. Ratcliffe, Clarence Robison

School of Natural Resources: Faculty Publications

“EEFlux” is an acronym for ‘Earth Engine Evapotranspiration Flux.’ EEFlux is based on the operational surface energy balance model “METRIC” (Mapping ET at high Resolution with Internalized Calibration), and is a Landsat-imagebased process. Landsat imagery supports the production of ET maps at resolutions of 30 m, which is the scale of many human-impacted and human-interest activities including agricultural fields, forest clearcuts and vegetation systems along streams. ET over extended time periods provides valuable information regarding impacts of water consumption on Earth resources and on humans. EEFlux uses North American Land Data Assimilation System hourly gridded weather data collection for energy …

Fitting Measured Evapotranspiration Data To The Fao56 Dual Crop Coefficient Method, R G. Allen, Ayse Kilic, Andrew Suyker, Jane A. Okalebo

School of Natural Resources: Faculty Publications

The FAO-56 publication of the UN Food and Agriculture Organization contains guidelines on constructing and applying a ‘dual crop coefficient’ method to characterize the behavior of evapotranspiration (ET) on a day to day basis. The dual crop coefficient (Kc) method substantially improves the ability to fit simulated with measured data, as compared to the ‘single’ Kc method, by partitioning evaporation from soil (Es) from transpiration from vegetation. This permits the separate estimation of Es when there are known wetting events from precipitation and irrigation and assists in explaining behavior of measured data. The application of the dual Kc method is …

Application Of Remote Sensing For Quantifying And Mapping Surface Energy Fluxes In South Central Nebraska: Analyses With Respect To Field Measurements, Vivek Sharma, Suat Irmak, Ayse Kilic, Denis Mutibwa

School of Natural Resources: Faculty Publications

Large-scale quantification of crop evapotranspiration (ETc) from various vegetation surfaces can aid in planning, managing, and allocating water resources. Field measurement of surface energy fluxes, including ETc, remains (and should remain) a crucial process for calibration and validation of satellite/remote sensing-based methods, which can provide important supporting information for water balance assessments and for analyzing the spatial distribution of energy fluxes on large scales. The Surface Energy Balance System (SEBS) was evaluated in estimating surface energy fluxes in south central Nebraska using Landsat imagery and meteorological data. SEBS-estimated surface energy fluxes were compared to Bowen Ratio Energy Balance System (BREBS) …

Decision Support Tools To Address Climate Change: Climate Model–Land Surface Models, Zea Mays L. (Corn) Phenology And Evapotranspiration–Yield Sensitivity Models For Nebraska, Usa, Jane A. Okalebo

School of Natural Resources: Dissertations, Theses, and Student Research

Nebraska's climate is highly variable and is expected to change in the future with anthropogenic global warming (AGW), resulting in warmer spring and summer temperatures coupled with more erratic rainfall events. This has strong implications for agriculture in the region, yet it is not clear that current modeling and decision-support tools are adequate to address these looming changes and provide planning, mitigation and adaptation strategies. To address climate change and its implications to agriculture in Nebraska, a set of robust decision support tools are very crucial. This study herein are divided into three chapters, with each chapter addressing a specific …

Parameterization Of The Satellite-Based Model (Metric) For The Estimation Of Instantaneous Surface Energy Balance Components Over A Drip-Irrigated Vineyard, Marcos Carrasco-Benavides, Samuel Ortega-Farias, Luis Octavio Lagos, Jan Kleissl, Luis Morales-Salinas, Ayse Kilic

School of Natural Resources: Faculty Publications

A study was carried out to parameterize the METRIC (Mapping EvapoTranspiration at high Resolution with Internalized Calibration) model for estimating instantaneous values of albedo (shortwave albedo) (αi), net radiation (Rni) and soil heat flux (Gi), sensible (Hi) and latent heat (LEi) over a drip-irrigated Merlot vineyard (location: 35°25′ LS; 71°32′ LW; 125 m.a.s. (l). The experiment was carried out in a plot of 4.25 ha, processing 15 Landsat images, which were acquired from 2006 to 2009. An automatic weather station was placed inside the experimental plot to measure αi, …

Recent Updates Of The Calibration-Free Evapotranspiration Mapping (Cremap) Method, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Modeling Rain-Fed Maize Vulnerability To Droughts Using The Standardized Precipitation Index From Satellite Estimated Rainfall-Southern Malawi Case Study, Harikishan Jayanthi, Gregory J. Husak, Chris Funk, Tamuka Magadzire, Adams Chavula, James P. Verdin

United States Geological Survey: Staff Publications

During 1990s, disaster risk reduction emerged as a novel, proactive approach to managing risks from natural hazards. The World Bank, USAlD, and other international donor agencies began making efforts to mainstream disaster risk reduction in countries whose population and economies were heavily dependent on rain-fed agriculture. This approach has more significance in light of the increasing climatic hazard patterns and the climate scenarios projected for different hazard prone countries in the world. The Famine Early Warning System Network (FEWS NET) has been monitoring the food security issues in the sub-Saharan Africa, Asia and in Haiti. FEWS NET monitors the rainfall …

Impacts Of Climate Change On The Surface Water Balance Of The Central United States, 1984–2007, Bo Dong

School of Natural Resources: Dissertations, Theses, and Student Research

The climate system and the hydrologic cycle are strongly connected with each other. Understanding the interactions between these two systems is important, since variations in climate can trigger extensive changes in the hydrologic cycle, with significant impacts on agriculture, ecosystems, and society. Observations over the central U.S. in recent decades show numerous changes in climatic variables. This includes decreases in cloud cover and wind speed, increases in air temperature, and seasonal shifts in precipitation rate and rain/snow fraction. To assess the impacts of these variations in climate on the regional water cycle, a terrestrial ecosystem/land surface hydrologic model (Agro-IBIS) is …

Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Vegetation and climate both play integral roles in water availability, particularly for arid to semi-arid regions. Changes in these variables can lead to extreme shortages in water for regions that rely on water for crop irrigation (i.e., the Great Plains). The objective of this study is to evaluate the impacts of vegetation on water availability in the Republican River basin in central Nebraska. Decreases in streamflow have been observed in the river basin for many years and, as a result, an invasive riparian plant species (Phragmites australis) is being removed in an effort to reduce evapotranspiration and reclaim …