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Drought

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Full-Text Articles in Geography

Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome, Andrew Felton, Gregory R. Goldsmith Feb 2023

Timing And Magnitude Of Drought Impacts On Carbon Uptake Across A Grassland Biome, Andrew Felton, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Although drought is known to negatively impact grassland functioning, the timing and magnitude of these impacts within a growing season remains unresolved. Previous small-scale assessments indicate grasslands may only respond to drought during narrow periods within a year; however, large-scale assessments are now needed to uncover the general patterns and determinants of this timing. We combined remote sensing datasets of gross primary productivity and weather to assess the timing and magnitude of grassland responses to drought at 5 km2 temporal resolution across two expansive ecoregions of the western US Great Plains biome: the C4-dominated shortgrass steppe and …


A Century Of Drought In HawaiʻI: Geospatial Analysis And Synthesis Across Hydrological, Ecological, And Socioeconomic Scales, Abby G. Frazier, Christian P. Giardina, Thomas W. Giambelluca, Laura Brewington, Yi Leng Chen, Pao Shin Chu, Lucas Berio Fortini, Danielle Hall, David A. Helweg, Victoria W. Keener, Ryan J. Longman, Matthew P. Lucas, Alan Mair, Delwyn S. Oki, Julian J. Reyes, Stephanie G. Yelenik, Clay Trauernicht Oct 2022

A Century Of Drought In HawaiʻI: Geospatial Analysis And Synthesis Across Hydrological, Ecological, And Socioeconomic Scales, Abby G. Frazier, Christian P. Giardina, Thomas W. Giambelluca, Laura Brewington, Yi Leng Chen, Pao Shin Chu, Lucas Berio Fortini, Danielle Hall, David A. Helweg, Victoria W. Keener, Ryan J. Longman, Matthew P. Lucas, Alan Mair, Delwyn S. Oki, Julian J. Reyes, Stephanie G. Yelenik, Clay Trauernicht

Geography

Drought is a prominent feature of Hawaiʻi’s climate. However, it has been over 30 years since the last comprehensive meteorological drought analysis, and recent drying trends have emphasized the need to better understand drought dynamics and multi-sector effects in Hawaiʻi. Here, we provide a comprehensive synthesis of past drought effects in Hawaiʻi that we integrate with geospatial analysis of drought characteristics using a newly developed 100-year (1920–2019) gridded Standardized Precipitation Index (SPI) dataset. The synthesis examines past droughts classified into five categories: Meteorological, agricultural, hydrological, ecological, and socioeconomic drought. Results show that drought duration and magnitude have increased significantly, consistent …


A Process-Model Perspective On Recent Changes In The Carbon Cycle Of North America, Guillermo Murray-Tortarolo, Benjamin Poulter, Rodrigo Vargas, Daniel Hayes, Anna M. Michalak, Christopher A. Williams, Lisamarie Windham-Myers, Jonathan A. Wang, Kimberly P. Wickland, David Butman, Hanqin Tian, Stephen Sitch, Pierre Friedlingstein, Mike O’Sullivan, Peter Briggs, Vivek Arora, Danica Lombardozzi, Atul K. Jain, Wenping Yuan, Roland Séférian, Julia Nabel, Andy Wiltshire, Almut Arneth, Sebastian Lienert, Sönke Zaehle, Vladislav Bastrikov, Daniel Goll, Nicolas Vuichard, Anthony Walker, Etsushi Kato, Xu Yue, Zhen Zhang Jan 2022

A Process-Model Perspective On Recent Changes In The Carbon Cycle Of North America, Guillermo Murray-Tortarolo, Benjamin Poulter, Rodrigo Vargas, Daniel Hayes, Anna M. Michalak, Christopher A. Williams, Lisamarie Windham-Myers, Jonathan A. Wang, Kimberly P. Wickland, David Butman, Hanqin Tian, Stephen Sitch, Pierre Friedlingstein, Mike O’Sullivan, Peter Briggs, Vivek Arora, Danica Lombardozzi, Atul K. Jain, Wenping Yuan, Roland Séférian, Julia Nabel, Andy Wiltshire, Almut Arneth, Sebastian Lienert, Sönke Zaehle, Vladislav Bastrikov, Daniel Goll, Nicolas Vuichard, Anthony Walker, Etsushi Kato, Xu Yue, Zhen Zhang

Geography

Continental North America has been found to be a carbon (C) sink over recent decades by multiple studies employing a variety of estimation approaches. However, several key questions and uncertainties remain with these assessments. Here we used results from an ensemble of 19 state-of-the-art dynamic global vegetation models from the TRENDYv9 project to improve these estimates and study the drivers of its interannual variability. Our results show that North America has been a C sink with a magnitude of 0.37 ± 0.38 (mean and one standard deviation) PgC year−1 for the period 2000–2019 (0.31 and 0.44 PgC year−1 in each …


Human Influences And Decreasing Synchrony Between Meteorological And Hydrological Droughts In Wisconsin Since The 1980s, Woonsup Choi, Susan Ann Borchardt, Jinmu Choi Apr 2021

Human Influences And Decreasing Synchrony Between Meteorological And Hydrological Droughts In Wisconsin Since The 1980s, Woonsup Choi, Susan Ann Borchardt, Jinmu Choi

Geography Faculty Articles

Hydrological droughts are important for agriculture and other human activities such as navigation and groundwater pumping, so it is necessary to understand their characteristics at various temporal and spatial scales. This study aims to examine the characteristics of hydrological droughts and their propagation from meteorological droughts across Wisconsin. Hydrological droughts were identified for twenty-four U.S. Geological Survey streamflow monitoring sites using the 20th percentile threshold level for each calendar day. Meteorological droughts were identified in the same way using daily precipitation data. Drought events of both types were identified for the period from 1980 to 2018, and the drought in …


Assessing And Mapping The Spatial-Temporal Change In Forest Phenology Of Arabuko-Sokoke Forest Using Moderate Resolution Satellite, Bailey Ytterdahl Apr 2021

Assessing And Mapping The Spatial-Temporal Change In Forest Phenology Of Arabuko-Sokoke Forest Using Moderate Resolution Satellite, Bailey Ytterdahl

Independent Study Project (ISP) Collection

This study focuses on coastal forests in Kenya that have some of the highest variety of flora and fauna, specifically Arabuko Sokoke Forest. Arabuko Sokoke Forest is located 110 miles north of Mombasa and 18 kilometers south of Malindi. This forest is known to be a worldwide biodiversity hotspot that is home to endemic and rare plants and animals. Within the Arabuko Sokoke Forest ecosystem, there are two main issues that challenge the conservation of the area. First, there has been more competition for land, primarily for agriculture and development. Second, there is an increase demand for forest resources due …


Field-Scale Soil Moisture Bridges The Spatial-Scale Gap Between Drought Monitoring And Agricultural Yields, Noemi Vergopolan, Sitian Xiong, Lyndon Estes, Niko Wanders, Nathaniel W. Chaney, Eric F. Wood, Megan Konar, Kelly Caylor, Hylke E. Beck, Nicolas Gatti, Tom Evans, Justin Sheffield Jan 2021

Field-Scale Soil Moisture Bridges The Spatial-Scale Gap Between Drought Monitoring And Agricultural Yields, Noemi Vergopolan, Sitian Xiong, Lyndon Estes, Niko Wanders, Nathaniel W. Chaney, Eric F. Wood, Megan Konar, Kelly Caylor, Hylke E. Beck, Nicolas Gatti, Tom Evans, Justin Sheffield

Geography

Soil moisture is highly variable in space and time, and deficits (i.e., droughts) play an important role in modulating crop yields. Limited hydroclimate and yield data, however, hamper drought impact monitoring and assessment at the farm field scale. This study demonstrates the potential of using field-scale soil moisture simulations to support highresolution agricultural yield prediction and drought monitoring at the smallholder farm field scale. We present a multiscale modeling approach that combines HydroBlocks a physically based hyper-resolution land surface model (LSM) with machine learning. We used HydroBlocks to simulate root zone soil moisture and soil temperature in Zambia at 3 …


Long-Term, Gridded Standardized Precipitation Index For Hawai‘I, Matthew P. Lucas, Clay Trauernicht, Abby G. Frazier, Tomoaki Miura Dec 2020

Long-Term, Gridded Standardized Precipitation Index For Hawai‘I, Matthew P. Lucas, Clay Trauernicht, Abby G. Frazier, Tomoaki Miura

Geography

Spatially explicit, wall-to-wall rainfall data provide foundational climatic information but alone are inadequate for characterizing meteorological, hydrological, agricultural, or ecological drought. The Standardized Precipitation Index (SPI) is one of the most widely used indicators of drought and defines localized conditions of both drought and excess rainfall based on period-specific (e.g., 1-month, 6-month, 12-month) accumulated precipitation relative to multi-year averages. A 93-year (1920–2012), high-resolution (250 m) gridded dataset of monthly rainfall available for the State of Hawai‘i was used to derive gridded, monthly SPI values for 1-, 3-, 6-, 9-, 12-, 24-, 36-, 48-, and 60-month intervals. Gridded SPI data were …


Integrated Approaches To Understanding And Reducing Drought Impact On Food Security Across Scales, Xiaogang He, Lyndon Estes, Megan Konar, Di Tian, Daniela Anghileri, Kathy Baylis, Tom P. Evans, Justin Sheffield Oct 2019

Integrated Approaches To Understanding And Reducing Drought Impact On Food Security Across Scales, Xiaogang He, Lyndon Estes, Megan Konar, Di Tian, Daniela Anghileri, Kathy Baylis, Tom P. Evans, Justin Sheffield

Geography

Understanding the cross-scale linkages between drought and food security is vital to developing tools to reduce drought impacts and support decision making. This study reviews how drought hazards transfer to food insecurity through changes in physical processes and socio-environmental systems across a wide range of spatial and temporal scales. We propose a multi-scale, integrated framework leveraging modeling advances (e.g. drought and crop monitoring, water-food-energy nexus, decision making) and increased data availability (e.g. satellite remote sensing, food trade) through the lens of the coupled human–natural system to support multidisciplinary approaches and avoid potential policy spillover effects. We discuss current scale-dependent challenges …


A Sediment-Based Reconstruction Of Caribbean Effective Precipitation During The ‘Little Ice Age’ From Freshwater Pond, Barbuda, Michael J. Burn, Jonathan Holmes, Lisa M. Kennedy, Allison Bain, Jim D. Marshall, Sophia Perdikaris Jan 2016

A Sediment-Based Reconstruction Of Caribbean Effective Precipitation During The ‘Little Ice Age’ From Freshwater Pond, Barbuda, Michael J. Burn, Jonathan Holmes, Lisa M. Kennedy, Allison Bain, Jim D. Marshall, Sophia Perdikaris

School of Global Integrative Studies: Faculty Publications

Contemporary climate dynamics of the circum-Caribbean Region are characterized by significant precipitation variability on interannual and interdecadal timescales controlled primarily by El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO). However, our understanding of pre-industrial climate variability in the region is hampered by the sparse geographic distribution of paleoclimate archives. Here, we present a high-resolution reconstruction of effective precipitation for Barbuda since the mid-16th Century, based on biostratigraphic and stable isotope analyses of fossil ostracods and gastropods recovered from lake sediment cores from Freshwater Pond, the only freshwater lake on the island. We interpret episodic fluctuations in shell …


Aridity, Bert Chapman May 2013

Aridity, Bert Chapman

Libraries Faculty and Staff Scholarship and Research

Provides an overview of how aridity in the American West has influenced that region's economic, environmental, and political development and U.S. Government policies in this region.


Late Holocene Activation History Of The Stanton Dunes, Northeastern Nebraska, Rebecca A. Puta, Paul R. Hanson, Aaron R. Young Apr 2013

Late Holocene Activation History Of The Stanton Dunes, Northeastern Nebraska, Rebecca A. Puta, Paul R. Hanson, Aaron R. Young

Great Plains Research: A Journal of Natural and Social Sciences

The Nebraska Sandhills have been an important resource for better understanding dune activation and the nature of prehistoric Great Plains drought events. However, until recently, few studies have focused on documenting the activation histories of smaller dune fields found along the Great Plains' eastern margin. This study focuses on the Stanton dune field, which lies about 145 km east of the Nebraska Sandhills on an alluvial terrace of the Elkhorn River in northeastern Nebraska. Sediments in the Stanton Dunes were dated with optically stimulated luminescence (OSL) to determine when these dunes were active. The ages indicate three activation periods that …


Roles Of Perceived Control And Planning In Ranch Drought Preparedness, Tonya Haigh, Cody Knutson Apr 2013

Roles Of Perceived Control And Planning In Ranch Drought Preparedness, Tonya Haigh, Cody Knutson

Great Plains Research: A Journal of Natural and Social Sciences

Ranchers in the Great Plains and across the United States face the threat of periodic drought. Though ranchers might minimize losses through drought-preparedness activities, many do not adequately prepare for drought, in part because of perceptions that the outcomes of drought management are not controllable. We explore how drought planning activities affect ranchers' perceptions of control and drought preparedness using the theories of planned behavior and goal attainment as guiding frameworks. Ten Great Plains ranchers who had engaged in drought management activities were interviewed about their plans. From the interviews, three activities emerged that appeared to increase ranchers' perceived control …


Sequias En El Sur De La Peninsula De Yucatan: Analisis De La Variabilidad Anual Y Estacional De La Precipitacion (Droughts In The Southern Yucatan Peninsula: Analysis Of The Annual And Seasonal Precipitation Variability), Sofia Mardero, Elsa Nickl, Birgit Schmook, Laura Schneider, John Rogan, Zachary Christman, Deborah Lawrence Aug 2012

Sequias En El Sur De La Peninsula De Yucatan: Analisis De La Variabilidad Anual Y Estacional De La Precipitacion (Droughts In The Southern Yucatan Peninsula: Analysis Of The Annual And Seasonal Precipitation Variability), Sofia Mardero, Elsa Nickl, Birgit Schmook, Laura Schneider, John Rogan, Zachary Christman, Deborah Lawrence

School of Earth & Environment Faculty Scholarship

Paper is in Spanish. English abstract: This study analyzes the spatial and temporal variability of precipitation across the Southern Yucatán Peninsula in Mexico, addressing the anomalies and trends of annual and seasonal precipitation as well as the occurrence of meteorological droughts, using rainfall data from nine weather stations during the period 1953-2007. Linear regression in the annual and seasonal rainfall were used to analyze the increase or decrease in precipitation trends over this period. Precipitation anomalies enabled the evaluation of the stability, deficit, or surplus of precipitation for each year or season, and a quintile method was used to …


Evaluating Vegetation Response To Water Stress Using Close-Range And Satellite Remote Sensing, Sharmistha Swain May 2012

Evaluating Vegetation Response To Water Stress Using Close-Range And Satellite Remote Sensing, Sharmistha Swain

Department of Geography: Dissertations, Theses, and Student Research

Drought is a weather related natural disaster that occurs in virtually all climatic zones of the world. In the last century, almost all parts of the contiguous United States have experienced several prolonged drought events with considerable impacts on the agricultural economy and environment. With changing climates, the droughts are expected to be more severe, longer, and widespread in many parts of the world including sections of the United States. Understanding the response of vegetation to water stress using remote sensing technologies will enhance our ability to detect and monitor drought. This research evaluates the response of vegetation to drought-related …


Does Terrestrial Drought Explain Global Co 2 Flux Anomalies Induced By El Niño?, C. R. Schwalm, Christopher A. Williams, K. Schaefer, I. Baker, G. J. Collatz, C. Rödenbeck Jan 2011

Does Terrestrial Drought Explain Global Co 2 Flux Anomalies Induced By El Niño?, C. R. Schwalm, Christopher A. Williams, K. Schaefer, I. Baker, G. J. Collatz, C. Rödenbeck

Geography

The El Niño Southern Oscillation is the dominant year-to-year mode of global climate variability. El Niño effects on terrestrial carbon cycling are mediated by associated climate anomalies, primarily drought, influencing fire emissions and biotic net ecosystem exchange (NEE). Here we evaluate whether El Niño produces a consistent response from the global carbon cycle. We apply a novel bottom-up approach to estimating global NEE anomalies based on FLUXNET data using land cover maps and weather reanalysis. We analyze 13 years (1997-2009) of globally gridded observational NEE anomalies derived from eddy covariance flux data, remotely-sensed fire emissions at the monthly time step, …


Reanalysis Data Underestimate Significant Changes In Growing Season Weather In Kazakhstan, C. K. Wright, K. M. De Beurs, Z. K. Akhmadiyeva, P. Y. Groisman, G. M. Henebry Oct 2009

Reanalysis Data Underestimate Significant Changes In Growing Season Weather In Kazakhstan, C. K. Wright, K. M. De Beurs, Z. K. Akhmadiyeva, P. Y. Groisman, G. M. Henebry

Natural Resource Management Faculty Publications

We present time series analyses of recently compiled climate station data which allowed us to assess contemporary trends in growing season weather across Kazakhstan as drivers of a significant decline in growing season normalized difference vegetation index (NDVI) recently observed by satellite remote sensing across much of Central Asia. We used a robust nonparametric time series analysis method, the seasonal Kendall trend test to analyze georeferenced time series of accumulated growing season precipitation (APPT) and accumulated growing degree-days (AGDD). Over the period 2000–2006 we found geographically extensive, statistically significant (p < 0.05) decreasing trends in APPT and increasing trends in AGDD. The temperature trends were especially apparent during the warm season and coincided with precipitation decreases in northwest Kazakhstan, indicating that pervasive drought conditions and higher temperature excursions were the likely drivers of NDVI declines observed in Kazakhstan over the same period. We also compared the APPT and AGDD trends at individual stations with results from trend analysis of gridded monthly precipitation data from the Global Precipitation Climatology Centre (GPCC) Full Data Reanalysis v4 and gridded daily near surface air temperature from the National Centers for Climate Prediction Reanalysis v2 (NCEP R2). We found substantial deviation between the station and the reanalysis trends, suggesting that GPCC and NCEP data substantially underestimate the geographic extent of recent drought in Kazakhstan. Although gridded climate products offer many advantages in ease of use and complete coverage, our findings for Kazakhstan should serve as a caveat against uncritical use of GPCC and NCEP reanalysis data and demonstrate the importance of compiling and standardizing daily climate data from data-sparse regions like Central Asia.


Dual Scale Trend Analysis Distinguishes Climatic From Anthropogenic Effects On The Vegetated Land Surface, K. M. De Beurs, C. K. Wright, G. M. Henebry Oct 2009

Dual Scale Trend Analysis Distinguishes Climatic From Anthropogenic Effects On The Vegetated Land Surface, K. M. De Beurs, C. K. Wright, G. M. Henebry

Natural Resource Management Faculty Publications

We present a dual scale trend analysis for characterizing and comparing two contrasting areas of change in Russia and Kazakhstan that lie less than 800 km apart. We selected a global NASA MODIS (moderate resolution imaging spectroradiometer) product (MCD43C4 and MCD43A4) at a 0.05◦ (∼5.6 km) and 500 m spatial resolution and a 16-day temporal resolution from 2000 to 2008. We applied a refinement of the seasonal Kendall trend method to the normalized difference vegetation index (NDVI) image series at both scales. We only incorporated composites during the vegetative growing season which was delineated by start of season and end …


Wither The Fruited Plain: The Long Expedition And The Description Of The "Great American Desert", Kevin Z. Sweeney Apr 2005

Wither The Fruited Plain: The Long Expedition And The Description Of The "Great American Desert", Kevin Z. Sweeney

Great Plains Quarterly

The view from Pikes Peak is breathtaking. Situated where the Great Plains meets the Rocky Mountains, one feels as if the whole nation is laid out before you. It is the perfect vantage point from which to write an inspirational anthem to the environmental magnificence of the United States. In the summer of 1893, Katherine Lee Bates, a Wellesley College English professor, sat on the summit of Pikes Peak, inspired by the panorama to pen the words to "America the Beautiful." Her poem was set to the tune "Materna" by Samuel Augustus Ward two years later to become one of …


Nebraska Droughts A Study Of Their Past Chronological And Spatial Extent With Implications For The Future, Merlin P. Lawson, Allan Reiss, Randy Phillips, Kenneth Livingston Jan 1971

Nebraska Droughts A Study Of Their Past Chronological And Spatial Extent With Implications For The Future, Merlin P. Lawson, Allan Reiss, Randy Phillips, Kenneth Livingston

Department of Geography: Faculty Publications

The purpose of this study was to measure the spatial and temporal dimensions of drought occurrence in Nebraska. Such interpretations were facilitated by the computer generation of 468 maps showing monthly values of drought in Nebraska, from 1931 through 1969. While it was found that the frequency of consecutive drought is least in the central portion of the state, the intensity of drought is greatest in this region. Maps of correspondence which relate the areal correlation between rural population density and precipitation also indicate high positive relationships for central Nebraska. Interpretation of tree ring growth values using moving t-test plots …