Defenses for Spring 2025
Constraining Satellite Precipitation Biases Through Geophysical Arguments
July 15, 2025
Eric Goldenstern
Passive microwave satellite precipitation products provide crucial information on global rainfall and the only source of such information over much of the world. These products operate under the assumption that microwave brightness temperature (TB) is sufficient to constrain rainfall. This information, however, often represents multiple rain states, resulting in substantial and highly variable…
Studying Climate Intervention Scenarios with Data Science Methods
July 07, 2025
Charlotte Connolly
Stratospheric aerosol injection (SAI) is a proposed climate intervention strategy that may temporarily alleviate the most severe climate change impacts. The ways in which a possible SAI deployment may occur are vast and often require social, environmental, and political consideration. To help scientists decide which of the many possible futures to study, scenario design methods are often used.…
Dynamics of Convective Organization in African Easterly Waves observed during the NAMMA and CPEX-CV Field Campaigns
June 26, 2025
Delián Colón-Burgos
The mechanisms that govern the organization of moist convection in weakly rotating flows such as tropical easterly waves are not fully understood. In this study we aim to better understand the dynamical processes that govern the convective organization at the meso-alpha scale, including the location, and intensity of deep convection, using NASA airborne field campaign and satellite…
From Sailors to Satellites: Investigating the Maritime Mystery of Bioluminescent Milky Seas
June 25, 2025
Justin Hudson
Bioluminescence, the ability of living organisms to produce and emit light, has been a topic of human imagination and scientific study for millennia. Bioluminescence is observed in a myriad of forms in the ocean, among these bioluminescent displays milky seas stand out as perhaps one of the rarest, most poorly understood, and most awe-inspiring forms of bioluminescence. Milky seas are…
Future Projections of the 2011 Super Tornado Outbreak Under Global Warming and Stratospheric Aerosol Injection
June 20, 2025
Bali Summers
Disasters associated with hazardous convective weather including severe thunderstorms, tornadoes, strong winds, large hail, and flooding, have been increasing in both frequency and cost. Previous studies using convection-permitting regional models show that climate change is likely to produce a future with fewer weak thunderstorms but more strong storms through increases in both convective…
Turning Up the Heat: Assessing 2-m Temperature Forecast Errors in AI Weather Prediction Models During Heat Waves
June 12, 2025
Kelsey Ennis
Extreme heat is the deadliest weather-related hazard in the United States. Furthermore, it is increasing in intensity, frequency, and duration, making skillful forecasts vital to protecting life and property. Traditional numerical weather prediction (NWP) models struggle with extreme heat for medium-range and subseasonal-to-seasonal (S2S) timescales. Meanwhile, artificial intelligence-based…
An Object-Based Analysis of Lightning Characteristics in a Pre-Tropical Cyclogenesis Environment
June 12, 2025
Nick Mesa
This work utilizes the continuous, high-resolution data provided by the Geostationary Lightning Mapper (GLM) on GOES-16 to investigate lightning attributes in a pre-tropical cyclogenesis environment in the North Atlantic. An object-based framework providing additional spatiotemporal characteristics was used to evaluate the area and optical energy of binned GLM lightning groups through the…
Evaporative Moisture Sources of Colorado’s Front Range: A Case Study of the Exceptionally Wet May-July Season of 2023
June 09, 2025
Kat Humphreys
In 2023, most of Colorado’s eastern plains experienced its wettest four-month period (May - August) out of 129 years of record (NOAA’s Monthly U.S. Climate Gridded Dataset). This extreme precipitation led to flash flooding, road washouts, and significant property damage among Colorado communities along the Front Range including Denver, Boulder, and Fort Collins. Although much is known…
Conditions leading to extrinsic and intrinsic ecosystem change across large ensembles of climate futures
June 03, 2025
Daniel Hueholt
Natural climate variability and forced change influence ecosystems through the direct impacts of changing environmental conditions ("extrinsic change''), and by altering internal ecosystem dynamics ("intrinsic change''). While explicit representation of ecosystems remains challenging, Earth system models are often capable of capturing patterns of the regional-scale climate conditions which…
AI-Informed Model Analogs for Subseasonal-to-Seasonal Prediction
May 12, 2025
Jacob Landsberg
Subseasonal-to-seasonal forecasting is crucial for public health, disaster preparedness, and agriculture, and yet it remains a particularly challenging timescale to predict. We explore the use of an interpretable AI-informed model analog forecasting approach, previously employed on longer timescales, to improve S2S predictions. Using an artificial neural network, we learn a mask of weights to…
Understanding the Ability of the Southern Ocean to Influence the Southeastern Tropical Pacific
May 09, 2025
Yiyu Zheng
The tropical Pacific plays a central role in the climate system and is linked to two major challenges in climate modeling: persistent biases in simulations and large inter-model spread in projections. The Southern Ocean (SO) has a remote influence on sea surface temperatures (SST) in the southeastern tropical Pacific (SEP) through a teleconnection involving cloud feedbacks, oceanic upwelling,…
Smoky Skies and Polar Air: Aerosol Microphysics Across Scales
May 09, 2025
Nicole June
Atmospheric aerosol particles are important to understand as they have implications on climate and human health. These particles may be emitted directly or form in the atmosphere through secondary processes. In this dissertation, we focus on two systems of aerosol sources, microphysics, and chemistry: 1) wildfires and 2) the springtime marine Arctic. Biomass Burning Plume Injection Height:…
Aerosol and land surface impacts on tropical convective processes
April 30, 2025
Gabrielle “Bee" Leung
In this three-part dissertation, we investigate the dynamical and microphysical processes that determine how tropical convective clouds respond to changes in aerosols and land surface properties. We focus on the variability in such processes across thermodynamic environments and cloud types. Using a combination of large eddy simulations (LES), long-term satellite observations, and Lagrangian…
The Role of Internal Variability and External Forcing on the Emergence of Compound Events in the CESM2 Large Ensemble
April 15, 2025
Ashley Dwyer
Extreme hot and dry compound events pose significant hazards to human health, agriculture, and ecosystems, making it critical to better understand what drives their occurrence and spatiotemporal variability. Although the role of internal climate variability in driving compound events has been previously studied, we leverage a large ensemble to enable a more robust understanding of the response…
Improving Predictions and Generating Actionable Forecast Insights for Downslope Windstorms with Machine Learning
March 11, 2025
Casey Zoellick
Downslope windstorms are an extreme weather phenomenon characterized by accelerating winds down the lee slope of a mountain with gusts often exceeding 45 m s-1. These impact society through damage directly related to the high winds, ground transportation concerns in the vicinity of the windstorm, aviation impacts through the accompanying mountain wave turbulence, and fueling the rapid…
The Impact of Stratospheric Aerosol Injection: A Regional Case Study
March 10, 2025
Sabrina Cohen
Stratospheric aerosol injection (SAI) is a form of climate intervention that has been proposed to limit future warming and mitigate some of the adverse impacts of climate change while humanity continues efforts to reduce emissions and atmospheric concentrations of greenhouse gases. In this study, we use an Earth system model to compare the projected effects of a climate change scenario to…
Cold Pool Propagation and Cold Pool-Land Surface Interactions
February 24, 2025
Nicholas Falk
Convective cold pools are important components of the Earth system as they influence processes such as deep convective initiation, storm longevity and intensity, surface energy fluxes, and aerosol transport. The overarching goal of the research outlined in this dissertation is to investigate the propagation characteristics of cold pools, as well as the interactions between cold pools and the…
Comparison of Microphysical and Topographical Influences on Warm Season Storm Electrification Between Subtropical South America and Colorado
February 19, 2025
Mitchell Gregg
Sixteen years of observations from the Tropical Rainfall Measurement Mission (TRMM) satellite’s Precipitation Radar were key in identifying subtropical South America in the lee of the Andes as a global hotspot for convection, with frequent back-building over terrain producing intense convection yielding some of the highest lightning flash rates on Earth. These observations motivated the 2018…
Eulerian and Lagrangian Analyses of Bioaerosol Transport in Three Deep Convective Storm Morphologies
February 18, 2025
Charles Davis
In this thesis, we investigate the entrainment and transport of aerosol particles in a representative isolated deep convective storm, supercell, and squall line using idealized high-resolution mesoscale model simulations. We focus our investigation on the extent to which air from rainy surface regions, which have been noted in the literature to be sites of aerosolization of biological…
Data-Driven Improvements to GPROF-Based Satellite Snowfall Retrievals with a Focus on Mountain Snowfall
January 27, 2025
Ryan Gonzalez
Snowfall is a critical component of Earth's hydrological and climate system despite only 5% of Earth's annual precipitation falling as snow. Satellite-based snowfall estimates, particularly those obtained from the Global Precipitation Measurement (GPM) Microwave Imager (GMI), struggle to accurately estimate the total annual snowfall accumulations, especially in mountainous regions of the…
REGULARIZED LINEAR REGRESSION TO ESTIMATE THE SPATIAL SENSITIVITY GOVERNING THE PATTERN EFFECT, COMPARATIVE ANALYSIS TO CONTEMPORARY METHODS, AND OBSERVATIONAL APPLICATIONS
January 22, 2025
Leif Fredericks
How the spatially varying temperature field affects global radiation (i.e., the "pattern effect") is crucial to understanding how sensitive Earth’s temperature is to anthropogenic forcing. We capture this phenomenon in a sensitivity map using regularized linear regression. When trained on 1,000 simulated years in a climate model, the resulting sensitivity maps are consistently able to…