Oceanography and Atmospheric Sciences and Meteorology Commons^™

Understanding And Predicting Precipitation Characteristics In The United States Through Machine Learning, Numerical Modeling And Measurements, Cody Luther Ratterman

All Graduate Theses and Dissertations, Fall 2023 to Present

Precipitation is one of the most important yet uncertain variables in the climate system. It varies dramatically in terms of timing, accumulation, rate, and phase, depending on location, season, circulation patterns, and atmospheric conditions. Precipitation forecasts, especially snowfall, are essential to supporting drought mitigation and water management in the Intermountain West. Because rainfall and snowfall lead to opposite effects on snowpack, accurately partitioning rain and snow is important to estimate snowpack levels, winter recreation, mountain ecosystems and runoff. The research findings in this dissertation have advanced the understanding and prediction of precipitation and snowpack in the U.S. by addressing the …

Hydroclimatic Whiplash Across The Contiguous United States: Characterizing Wet–Dry Transitions In Pdsi And Phdi, James Lam, Thomas Christopher Piechota

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Hydroclimatic whiplash, characterized by rapid transitions between wet and dry conditions, poses a growing challenge for water resource management and ecosystem stability. However, the spatial and statistical characteristics of wet–dry transitions across the contiguous United States are not fully understood. This study analyzed Palmer Drought Severity Index (PDSI) and Palmer Hydrological Drought Index (PHDI) records from 344 NOAA climate divisions spanning 1895–2024. Whiplash was defined as a transition between severe drought and severe wetness within 12-month rolling windows. Statistical descriptors including lag-1 autocorrelation, variance, and skewness were evaluated for whiplash and non-whiplash windows to assess differences between them. Whiplash hotspots …

Examining Extremes: A Comparison Between Machine Learning Based Southwestern Conus Seasonal Drought And High Fire Risk Event Synoptic Climatologies, Ethan M. Greenberg

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

The Southwestern United States (SW CONUS), comprised of California, Arizona, Nevada, and Utah, is a vast region that tens of millions of people call home. Hosting ecosystems ranging from grasslands and shrublands to temperate forests and climate zones ranging from Mediterranean climates to arid deserts, the region is nearly unanimously prone to intense droughts and devastating wildfires. While fire weather conditions and drought are often studied separately or mentioned as background conditions for the other, there are relatively few studies that compare the typical meteorological conditions between the two. This study aims to more closely understand the meteorological relationship between …

Dynamics, Predictability And Impacts Of Multi-Year La Niña Event, Nahid A. Hasan

All Graduate Theses and Dissertations, Fall 2023 to Present

This dissertation investigates the dynamics, predictability, and impacts of multi-year La Niña events. Multi-year La Niña events are referred to as extended periods of unusually cooler tropical Pacific that persist for two or more consecutive winters. These prolonged events can increase the risk of natural hazards such as droughts, floods, and heatwaves in the western US and around the world. Despite their worldwide significance, questions remain about the mechanisms driving their initiation, their predictability, and regional hydroclimate impacts.

The first chapter of the dissertation introduces what scientists currently believe causes them, and how well different types of climate models can …

Understanding Hydroclimate In The Contiguous United States: Roles Of Temperature Vs Precipitation And Subtropical Pacific Warming, Grace Esenam Affram

All Graduate Theses and Dissertations, Fall 2023 to Present

This study investigates the physical drivers and mechanisms of hydroclimate variability across the Contiguous United States (U.S.), using a combination of observable data, reanalysis data, land modeling, and coupled climate model experiments. One of the major findings is that the historic 2021 drought event across the Western U.S. was primarily driven by a severe lack of precipitation rather than increased temperatures. The study further finds that anthropogenic forcing has substantially increased the risk of this extreme drought by approximately 26 times relative to a world without the influence.

Additionally, the study reveals that the Pacific Meridional Mode (PMM) characterized by …

Atmospheric Teleconnection Patterns And Hydrological Whiplashes In The Western U.S., Wenzhao Li, Surendra Maharjan, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Western U.S. is undergoing notable transformations in its hydrological patterns, distinguished by rising variability and recurrent “whiplash” shifts between extreme wet and dry phases. Our comprehensive analysis of 469 streamflow stations from 1981 to 2023 reveals a substantial increase in hydrological whiplash events, with a peak of 206 stations experiencing dry-to-wet whiplash in the early 1990s. We establish strong links between these streamflow extremes and sub-seasonal to seasonal teleconnection factors, particularly the Western Pacific Oscillation (WP) and Eastern Pacific/North Pacific Oscillation (EPO). Additionally, we demonstrate the combined impacts of the El Niño-Southern Oscillation (ENSO) and the Madden-Julian Oscillation (MJO), …

A Climatological Analysis Of Drought And Flood In California, Kristen Faith Coston

Masters Theses

This research is investigating the climate states that produce droughts and floods and seeks to explain how a sudden shift from persistent drought to drought-alleviating flood is possible. Objectives include investigating how drought and flood in California are influenced by temperature and climate patterns, whether there are any correlation between climate/ocean indices and the Standardized Precipitation Index (SPI), and whether Atmospheric Rivers (ARS) are influenced by certain atmospheric/oceanic states.

All data is collected for 41 years, between 1983 and 2024. The SPI dataset is obtained by coding to filter for the mean value of all pixels in Sacramento County. Monthly …

Farm Profit Impacts Of Consecutive Drought Years Under Climate Scenarios In Southwestern Australia, Sud Kharel, Kevin J. Foster, Meredith M. Guthrie, Ross Kingwell

Climate Science Research Articles

Climate projections for southern Australia indicate an increased likelihood of years of consecutive droughts. How resilient are farm businesses and their farming systems to recover from episodic drought? This study assesses the farm economic and financial impacts of consecutive droughts in southwest Australia. Bioeconomic simulation modelling of farm businesses with different farming systems at three locations is used to examine the long-term financial consequences of consecutive droughts. Various key factors affecting those consequences are examined. Farm location, farming system and starting equity are found to be the main determinants of how quickly a farm business can financially recover from the …

Extraordinary 21st Century Drought In The Po River Basin (Italy), Abel Andrés Ramírez Molina, Glenn Tootle, Giuseppe Formetta, Thomas Piechota, Jiaqi Gong

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Recent research identified 2022 as being the year of lowest seasonal April–May–June–July (AMJJ) observed streamflow for the Po River Basin (PRB) in the past two centuries. Expanding upon this research, we applied filters (2-year to 30-year filters) to the AMJJ observed streamflow and identified the late 20th and 21st century as displaying extreme drought. In this study, we introduce PALEO-RECON, an automated reconstruction tool developed to leverage tree ring-based proxies and streamline regression processes. Using PALEO-RECON, we reconstructed the AMJJ streamflow, applying traditional regression techniques and using a nested approach in which 30-, 40-, and 50-year windows within the ~200-year …

Low-Emission Beef Production In The Southern Rangelands Of Western Australia: An Analysis Of Herd Structure And Stocking Rate Experiencing Droughts, Christophe D'Abbadie

Animal production and livestock research articles

Reconciling profitable cattle production with rangeland health and reduced emissions is a key challenge in the southern rangelands of Western Australia (WA). Stocking rate and herd structure selection are crucial decisions to achieve this balance. This study assessed the emission profiles of three contrasting herd structures (weaner production, live export, and slaughter production), and three stocking rates within a herd–carbon accounting modelling framework. The analysis considers the impact of varying drought frequencies on these cattle production systems. Herd models were developed for the semiarid southern WA rangelands. Stocking rates were set at 100%, 80% and 66% of the government recommended …

Applications Of Artificial Intelligence On Drought Impact Monitoring And Assessment, Beichen Zhang

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Drought, a prevalent and consequential natural disaster, poses widespread, indirect challenges across environmental and societal dimensions. Despite considerable focus on monitoring meteorological and hydrological drought and studying their characteristics, there is a gap in assessing its multifaceted impacts, especially on societal sectors. The dissertation comprises three research essays utilizing artificial intelligence to quantitatively study multi-dimensional drought impacts. The first essay leveraged deep learning and natural language processing to predict multi-dimensional drought impacts from textual datasets, including social media, news media, and citizen scientist reports. The findings demonstrate superior performance over traditional methods and unveil the spatial and temporal heterogeneity of …

Further Developing Drought Early Warning Information Systems Using Mixed-Methods And Multiple Streams Of Data, Caily Claire Schwartz

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Drought is a complex phenomenon with varying degrees of impacts and monitoring methods. No drought is alike, creating a challenge for both water managers and communities. No area is immune to a drought. Due to the cyclical nature of drought events, clear information to those impacted is necessary to reduce risk and move towards proactive responses, as opposed to reactive responses. To better provide communication and mitigation tools, Drought Early Warning Information Systems (DEWIS) have been developed in various regions and contexts. To improve early warning, an understanding of the end user’s perceptions of risk, and the applicability of data …

Assessment And Prediction Of Meteorological Drought Using Machine Learning Algorithms And Climate Data, Khalid En-Nagre, Mourad Aqnouy, Ayoub Ouarka, Syed Ali Asad Naqvi, Ismail Bouizrou, Jamal Eddine Stitou El Messari, Aqil Tariq, Walid Soufan, Wenzhao Li, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Monitoring drought in semi-arid regions due to climate change is of paramount importance. This study, conducted in Morocco’s Upper Drâa Basin (UDB), analyzed data spanning from 1980 to 2019, focusing on the calculation of drought indices, specifically the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at multiple timescales (1, 3, 9, 12 months). Trends were assessed using statistical methods such as the Mann-Kendall test and the Sen’s Slope estimator. Four significant machine learning (ML) algorithms, including Random Forest, Voting Regressor, AdaBoost Regressor, and K-Nearest Neighbors Regressor, were evaluated to predict the SPEI values for both three …

Heavy Steers And Heifers Run At Low Stocking Rates Enhance Drought Resilience In A Pastoral Region Of Australia, Christophe D'Abbadie, Ross Kingwell, Philip E. Vercoe, Bradley Plunkett, Alan Peggs

Animal production and livestock research articles

CONTEXT

The semi-arid mulga lands of the Southern Rangelands of Western Australia experience frequent droughts. Maintaining a profitable animal grazing enterprise whilst preserving rangeland condition requires selecting an appropriate stocking rate and herd structure.

OBJECTIVE

We construct and apply bioeconomic models of beef enterprises for the semi-arid Southern Rangelands of Western Australia, to assess the profitability and relative riskiness of three different livestock production systems and three different stocking rates when exposed to different frequencies of drought.

METHODS

We construct bio-economic models of herd structures that separately focus on producing either: (i) 200 kg heifers and 210 kg steers (ii) …

Water Whiplash In Mediterranean Regions Of The World, Citlalli Madrigal, Rama Bedri, Thomas Piechota, Wenzhao Li, Glenn Tootle, Hesham El-Askary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The presence of weather and water whiplash in Mediterranean regions of the world is analyzed using historical streamflow records from 1926 to 2023, depending on the region. Streamflow from the United States (California), Italy, Australia, Chile, and South Africa is analyzed using publicly available databases. Water whiplash—or the rapid shift of wet and dry periods—are compared. Wet and dry periods are defined based on annual deviations from the historical record average, and whiplash occurs when there is an abrupt change that overcomes an accommodated deficit or surplus. Of all the stations, there are more dry years (56%) than wet years …

Response Of Helenium Amarum To Environmental Stressors In The Presence Of Mycorrhizal Fungi And Its Role As A Pollinator Resource, Austin Jameson, Lisa Horth

Biological Sciences Faculty Publications

Globally, climate change is causing shifts in precipitation patterns. Shifting precipitation patterns can be a stressor for many species. One species that is experiencing such stress is Helenium amarum Raf (H. Rock). H. amarum, thrives in dry upland pastures and low-lying grassy and sandy habitat in the mid-Atlantic (USA), where it persists despite storm-driven standing water. Helenium amarum is a species that is toxic to livestock and has been found outside its native range. Temperature and light impacts on germination are already known, but the role of water availability and potential ameliorating effects of mycorrhizae during water stress have …

How Is Flash Drought Understood?—Experts’ Definitions And Decision-Makers’ Perceptions, Caily Schwartz, Tonya Haigh, Mark D. Svoboda, Madeline Goebel

National Drought Mitigation Center: Faculty Publications

Because flash drought is a relatively new phenomenon in drought research, defining the concept is critical for scientists and decision-makers. Having detrimental impacts on many sectors, it is important to have a consistent definition and understanding of flash drought, between experts and stakeholders, to provide early warning to the community. This study focuses on onset and progression of conditions and demonstrates the difference in flash drought identification for 15 events across six quantitative definitions of flash drought that use the U.S. Drought Monitor (USDM). Five flash drought events have been studied in the literature while 10 additional events have been …

The Patchwork Governance Of Ecologically Available Water: A Case Study In The Upper Missouri Headwaters, Montana, United States, Amanda E. Cravens, Julia B. Goolsby, Theresa Jedd, Deborah J. Bathke, Shelley Crausbay, Ashley E. Cooper, Jason Dunham, Tonya Haigh, Kimberly R. Hall, Michael J. Hayes, Jamie Mcevoy, Rebecca L. Nelson, Markéta Poděbradská, Aaron Ramirez, Elliot Wickham, Dionne Zoanni

National Drought Mitigation Center: Faculty Publications

Institutional authority and responsibility for allocating water to ecosystems (“ecologically available water” [EAW]) is spread across local, state, and federal agencies, which operate under a range of statutes, mandates, and planning processes. We use a case study of the Upper Missouri Headwaters Basin in southwestern Montana, United States, to illustrate this fragmented institutional landscape. Our goals are to (a) describe the patchwork of agencies and institutional actors whose intersecting authorities and actions influence the EAW in the study basin; (b) describe the range of governance mechanisms these agencies use, including laws, policies, administrative programs, and planning processes; and (c) assess …

Droughtscape, Summer 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Summer 2023

Hydroclimate Effects On Great Salt Lake Decline Since 1980, Siiri Joy Bigalke

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

As a terminal basin lake, the Great Salt Lake (GSL) is known to act as a barometer for low frequency climate variability for the Western United States. As thus, there are naturally occurring large changes to GSL elevation levels that vary on time scales from years to decades. However, amongst these naturally occurring interannual changes there has been a significant declining trend in the elevation levels since a string of anomalous pluvial years in the early 1980s. In the summer of 2022, the Great Salt Lake reached its lowest levels in recorded history, which coincided with a two-decades long regional …

The Last Drought Frontier: Building A Drought Index For The State Of Alaska, Olivia Campbell

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

Drought is characterized by periods of below average precipitation. There are five major types of drought recognized in the literature: meteorological, hydrological, agricultural, socioeconomic, and ecological. A relatively new concept in the drought literature is “snow drought.” A key part of the definition of drought is that it is not always accompanied by extreme heat. This means drought can occur even in cold climates, cold seasons, and higher latitudes and altitudes, like Alaska. Drought is a natural part of climate variability, but Alaska’s climate is changing faster than any other state in the United States. Alaska is no stranger to …

Physiological And Transcriptomic Responses Of Two Artemisia Californica Populations To Drought: Implications For Restoring Drought-Resilient Native Communities, Hagop S. Atamian Dr., Jennifer L. Funk

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

As climate change brings drier and more variable rainfall patterns to many arid and semi-arid regions, land managers must re-assemble appropriate plant communities for these conditions. Transcriptome sequencing can elucidate the molecular mechanisms underlying plant responses to changing environmental conditions, potentially enhancing our ability to screen suitable genotypes and species for restoration. We examined physiological and morphological traits and transcriptome sequences of coastal and inland populations of California sagebrush (Artemisia californica), a critical shrub used to restore coastal sage scrub vegetation communities, grown under low and high rainfall environments. The populations are located approximately 36 km apart but …

Droughtscape, Spring 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Spring 2023

Projected Long-Term Climate Trends Reveal The Critical Role Of Vapor Pressure Deficit For Soybean Yields In The Us Midwest, Wenguang Sun, David Fleisher, Dennis Timlin, Chittaranjan Ray, Zhuangji Wang, Sahila Beegum, Vangimalla Reddy

Nebraska Water Center: Faculty Publications

Extreme climate events including heat waves and droughts are projected to become more frequent under future climate change conditions. However, the mechanisms between soybean yields and climate factors, specifically involving variable rainfall and high heat episodes, are still unclear, particularly with respect to spatial trends in the United States (US) Midwest. A recently modified version of the model GLYCIM was used to evaluate rainfed soybean production across 12 states at a 10 km spatial resolution for three time periods (2011–2020, 2051–2060, 2091–2099) under Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5. Results showed that except for the northernmost Midwest counties, …

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 Workshop On Using Nasa Airs Data To Monitor Drought For The U.S. Drought Monitor, Alireza Farahmand,, Sharon Ray, Heidar Thrastarson, Stephen Licata, Stephanie Granger, Brian Fuchs

National Drought Mitigation Center: Faculty Publications

Recent studies indicate that drought indicators based on near-surface air relative humidity (RH), air temperature (T), and air vapor pressure deficit (VPD), derived from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA’s Aqua satellite can detect the onset of drought earlier than other drought indicators, specifically standardized precipitation index (SPI), which is widely used for drought onset detection. A recent study showed that standardized relative humidity index (SRHI) can detect drought signals earlier than SPI (Farahmand et al. 2015). Relative humidity is a climate variable defined as the ratio of air vapor pressure to saturated vapor pressure. Precipitation and relative …

Droughtscape, Winter 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Winter 2023

Spatiotemporal Variability Of Drought And Its Relationships To Enso And Iod Indices In Somaliland, Mohamed S Bile, Paul Ts Limbu

Tanzania Journal of Science

Drought is one of Somaliland’s most prevalent natural hazards, causing serious socioeconomic and environmental harm. This study investigated the spatial and temporal variability of drought and its relationships with El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) indices using the Standardized Evapotranspiration Index (SPEI) from 1981 to 2020. The Mann-Kendall trend test and Sen's slope estimator were used to assess the trends of annual and seasonal SPEI time series. The Empirical Orthogonal Function (EOF) was employed to examine the dominant modes of the SPEI series, and Pearson and partial correlation analyses were performed to investigate the associations between …

Future Colorado River Basin Drought And Surplus, Rama Bedri, Thomas Piechota

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Historical and future drought and surplus periods in the Colorado River basin are evaluated based on eight climate scenarios. Unimpaired streamflow from 17 stations in the Colorado River are evaluated based on U.S. Geological Survey, Bureau of Reclamation, and Coupled Modeled Intercomparison Projection 5 downscaled data from 1950–2099. Representative Concentration Pathway (RCP) 4.5 and 8.5 emission scenarios are considered for four climate models (HadGEM2-ES, CNRM-CM5, CanESM2, MI-ROC5). Drought (surplus) quantities, magnitudes, severities, and water year flows are compared for the historical and future periods. Results indicate that there is a significant difference between the historical record and future projections. The …

Comparative Behavioral Ecotoxicology Of Inland Silverside Larvae Exposed To Pyrethroids Across A Salinity Gradient, Sara J. Hutton, Samreen Siddiqui, Emily I. Pedersen, Christopher Y. Markgraf, Amelie Segarra, Michelle L. Hladik, Richard E. Connon, Susanne M. Brander

United States Geological Survey: Staff Publications

Pyrethroids, a class of commonly used insecticides, are frequently detected in aquatic environments, including estuaries. The influence that salinity has on organism physiology and the partitioning of hydrophobic chemicals, such as pyrethroids, has driven interest in how toxicity changes in saltwater compared to freshwater. Early life exposures in fish to pyrethroids cause toxicity at environmentally relevant concentrations, which can alter behavior. Behavior is a highly sensitive endpoint that influences overall organism fitness and can be used to detect toxicity of environmentally relevant concentrations of aquatic pollutants. Inland Silversides (Menidia beryllina), a commonly used euryhaline model fish species, were exposed …