Physical and Environmental Geography | Open Access Articles

Pronounced Increases In Nitrogen Emissions And Deposition Due To The Historic 2020 Wildfires In The Western U.S., Patrick C. Campbell, Daniel Tong, Rick Saylor, Yunyao Lii, Siqi Ma, Xiaoyang Zhang, Shoba Kondragunta, Fangjun Li

GSCE Faculty Publications

Wildfire outbreaks can lead to extreme biomass burning (BB) emissions of both oxidized (e.g., nitrogen oxides; NOx= NO+NO2) and reduced form(e.g., ammonia; NH3) nitrogen (N) compounds. High N emissions aremajor concerns for air quality, atmospheric deposition, and consequential human and ecosystemhealth impacts. In this study, we use both satellite-based observations and modeling results to quantify the contribution of BB to the total emissions, and approximate the impact on total N deposition in the western U.S. Our results show that during the 2020 wildfire season of August–October, BB contributes significantly to the total emissions, with a satellite-derived fraction of NH3 to …

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How Much Variation In Land Surface Phenology Can Climate Oscillation Modes Explain At The Scale Of Mountain Pastures In Kyrgyzstan?, Monika A. Tomaszewska, Geoffrey M. Henebry

NASA Land-Cover Land-Use Change Data Sets

Climate oscillation modes can shape weather across the globe due to atmospheric teleconnections. We built on the findings of a recent study to assess whether the impacts of teleconnections are detectable and significant in the early season dynamics of highland pastures across five rayons in Kyrgyzstan. Specifically, since land surface phenology (LSP) has already shown to be influenced by snow cover seasonality and terrain, we investigated here how much more explanatory and predictive power information about climatic oscillation modes might add to explain variation in LSP. We focused on seasonal values of five climate oscillation indices that influence vegetation dynamics …

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Land Surface Phenology In The Highland Pastures Of Montane Central Asia: Interactions With Snow Cover Seasonality And Terrain Characteristics, Monika A. Tomaszewska, Lan H. Nguyen, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

Many studies have shown that high elevation environments are among very sensitive to climatic changes and where impacts are exacerbated. Across Central Asia, which is especially vulnerable to climate change due to aridity, the ability of global climate projections to capture the complex dynamics of mountainous environments is particularly limited. Over montane Central Asia, agropastoralism constitutes a major portion of the rural economy. Extensive herbaceous vegetation forms the basis of rural economies in Kyrgyzstan. Here we focus on snow cover seasonality and the effects of terrain on phenology in highland pastures using remote sensing data for 2001–2017. First, we describe …

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Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

Few studies have examined changing snow seasonality in Central Asia. Here, we analyzed changes in the seasonality of snow cover across Kyrgyzstan (KGZ) over 14 years from 2002/03–2015/16 using the most recent version (v006) of MODIS Terra and Aqua 8 day snow cover composites (MOD10A2/MYD10A2).We focused on three metrics of snow seasonality—first date of snow, last date of snow, and duration of snow season—and used nonparametric trends tests to assess the significance and direction of trends. We evaluated trends at three administration scales and across elevation. We used two techniques to assure that our identification of significant trends was not …

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Northern Eurasia Future Initiative (Nefi): Facing The Challenges And Pathways Of Global Change In The Twenty-First Century, Pavel Groisman, Herman Shugart, David Kicklighter, Geoffrey Henebry, Nadezhda Tchebakova, Shamil Maksyutov, Erwan Monier, Garik Gutman, Sergey Gulev, Jiaguo Qi, Alexander Prishchepov, Elena Kukavskaya, Boris Porfiriev, Alexander Shiklomanov, Tatiana Loboda, Nikolay Shiklomanov, Son Nghiem, Kathleen Bergen, Jana Albrechtová, Jiquan Chen, Maria Shahgedanova, Anatoly Shvidenko, Nina Speranskaya, Amber Soja, Kirsten De Beurs, Olga Bulygina, Jessica Mccarty, Qianlai Zhuang, Olga Zolina

GSCE Faculty Publications

During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments …

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Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy

GSCE Faculty Publications

The Landsat 5 Thematic Mapper (TM) sensor provided the longest single mission terrestrial remote sensing data record but temporally sparse station keeping maneuvers meant that the Landsat 5 orbit changed over the 27 year mission life. Long-term Landsat 5 TM reflectance inconsistencies may be introduced by orbit change induced solar zenith variations combined with surface reflectance anisotropy, commonly described by the Bi-directional Reflectance Distribution Function (BRDF). This study quantifies the local overpass time and observed solar zenith angle changes for all the Landsat 5 TM images available at two latitudinally separated locations along the same north-south Landsat path (27) in …

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Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li

GSCE Faculty Publications

: Biomass burning is a global phenomenon and systematic burned area mapping is of increasing importance for science and applications. With high spatial resolution and novelty in band design, the recently launched Sentinel-2A satellite provides a new opportunity for moderate spatial resolution burned area mapping. This study examines the performance of the Sentinel-2A Multi Spectral Instrument (MSI) bands and derived spectral indices to differentiate between unburned and burned areas. For this purpose, five pairs of pre-fire and post-fire top of atmosphere (TOA reflectance) and atmospherically corrected (surface reflectance) images were studied. The pixel values of locations that were unburned in …

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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

GSCE Faculty Publications

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 …

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Detecting The Influence Of Best Management Practices On Vegetation Near Ephemeral Streams With Landsat Data, Matthew Rigge, Alexander Smart, Bruce Wylie, Kendall De Van Kamp

Natural Resource Management Faculty Publications

Various best management practices (BMPs) have been implemented on rangelands with the goals of controlling nonpoint sourcepollution, reducing the impact of livestock in ecologically important riparian areas, and improving grazing distribution.Providing off-stream water sources to livestock in pastures, cross-fencing, and rotational grazing are common rangeland BMPsthat have demonstrated success in drawing livestock grazing pressure away from streams. We evaluated the effects of rangelandBMP implementation with six commercial-scale pastures in the northern mixed-grass prairie. Four pastures received a BMPsuite consisting of off-stream water, cross-fencing, and deferred-rotation grazing, and two pastures did not receive BMPs. Wehypothesized that the BMPs increased the quantity …

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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

GSCE Faculty Publications

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 …

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

GSCE Faculty Publications

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 …

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Radiative Forcing Over The Conterminous United States Due To Contemporary Land Cover Use Change And Sensitivity To Snow And Interannual Albedo Variability, Christoper A. Barnes, David P. Roy

GSCE Faculty Publications

Satellite‐derived land cover land use (LCLU), snow and albedo data, and incoming surface solar radiation reanalysis data were used to study the impact of LCLU change from 1973 to 2000 on surface albedo and radiative forcing for 58 ecoregions covering 69% of the conterminous United States. A net positive surface radiative forcing (i.e., warming) of 0.029 Wm−2 due to LCLU albedo change from 1973 to 2000 was estimated. The forcings for individual ecoregions were similar in magnitude to current global forcing estimates, with the most negative forcing (as low as −0.367 Wm−2) due to the transition to forest and the …

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Large Seasonal Swings In Leaf Area Of Amazon Rainforests, Ranga B. Myneni, Wenze Yang, Ramakrishna R. Nemani, Alfredo R. Huete, Robert E. Dickinson, Yuri Knyazikhin, Kamel Didan, Rong Fu, Robinson I. Negron Juarez, Sasan S. Saatchi, Hirofumi Hashimoto, Kazuhito Ichii, Nikolay V. Shabanov, Bin Tan, Piyachat Ratana, Jeffrey L. Privette, Jeffrey T. Morisette, Eric F. Vermote, David P. Roy, Robert E. Wolfe, Mark A. Friedl, Steven W. Running, Petr Votava, Nazmi El-Saleous, Sadashiva Devadiga, Yin Su, Vincent V. Salomonson

GSCE Faculty Publications

Despite early speculation to the contrary, all tropical forests studied to date display seasonal variations in the presence of new leaves, flowers, and fruits. Past studies were focused on the timing of phenological events and their cues but not on the accompanying changes in leaf area that regulate vegetation–atmosphere exchanges of energy, momentum, and mass. Here we report, from analysis of 5 years of recent satellite data, seasonal swings in green leaf area of ~25% in a majority of the Amazon rainforests. This seasonal cycle is timed to the seasonality of solar radiation in a manner that is suggestive of …

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Fire-Induced Albedo Change And Its Radative Forcing At The Surface In Northern Austrailia, Y. Jin, David P. Roy

GSCE Faculty Publications

This paper investigates the impact of fire on surface albedo and the associated radiative forcing over 56% of continental Australia encompassing the fire-prone northern tropical savanna. Fire-affected areas and albedos are derived for the 2003 fire season using daily Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. Near-infrared and total shortwave albedos are observed to generally decrease after fire occurrence. Regionally, the total shortwave albedo drops by an average of 0.024, with increasing reductions as the dry season progresses and larger reductions in grasslands than woody savannas. These fire-induced albedo changes exert a positive forcing at the surface that increases …

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Full-Text Articles in Physical and Environmental Geography

Pronounced Increases In Nitrogen Emissions And Deposition Due To The Historic 2020 Wildfires In The Western U.S., Patrick C. Campbell, Daniel Tong, Rick Saylor, Yunyao Lii, Siqi Ma, Xiaoyang Zhang, Shoba Kondragunta, Fangjun Li

GSCE Faculty Publications

How Much Variation In Land Surface Phenology Can Climate Oscillation Modes Explain At The Scale Of Mountain Pastures In Kyrgyzstan?, Monika A. Tomaszewska, Geoffrey M. Henebry

NASA Land-Cover Land-Use Change Data Sets

Land Surface Phenology In The Highland Pastures Of Montane Central Asia: Interactions With Snow Cover Seasonality And Terrain Characteristics, Monika A. Tomaszewska, Lan H. Nguyen, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

GSCE Faculty Publications

Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy

GSCE Faculty Publications

Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li

GSCE Faculty Publications

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

GSCE Faculty Publications

Detecting The Influence Of Best Management Practices On Vegetation Near Ephemeral Streams With Landsat Data, Matthew Rigge, Alexander Smart, Bruce Wylie, Kendall De Van Kamp

Natural Resource Management Faculty Publications

GSCE Faculty Publications

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

GSCE Faculty Publications

Radiative Forcing Over The Conterminous United States Due To Contemporary Land Cover Use Change And Sensitivity To Snow And Interannual Albedo Variability, Christoper A. Barnes, David P. Roy

GSCE Faculty Publications

GSCE Faculty Publications

Fire-Induced Albedo Change And Its Radative Forcing At The Surface In Northern Austrailia, Y. Jin, David P. Roy

GSCE Faculty Publications