SPRING 2026
Wednesdays at 3:00 pm, Seminar Room SLAB 103 / Virtual SLAB 103
Jan 14: Dr. Lauren Zamora
University of Maryland College Park / NASA Goddard Space Flight Center, Greenbelt, MD
Guest of Paquita Zuidema, Department of Atmospheric Sciences
To Arctic Clouds From Saharan Dust: An Alumnus Career Retrospective
Recording Available at COMPASS ON DEMAND
Aerosol-cloud interactions are one of the largest sources of uncertainty in climate projections for the rapidly warming Arctic, particularly through their influence on the radiative properties of mixed‑phase clouds containing both liquid water and ice. In this talk, I will present a retrospective of my research on aerosol impacts on the environment, tracing a trajectory from PhD work at Rosenstiel on Saharan dust and atmospheric nutrient deposition to the ocean to my current focus on Arctic aerosol-cloud interactions. I will talk about how my training in marine and atmospheric chemistry with Dennis Hansell and Joe Prospero continues to inform my research approach. The presentation will focus primarily on recent developments in understanding Arctic aerosol-cloud interactions, including new satellite observational methods, community scientific priorities identified at a recent QuIESCENT international workshop, and new observations from NASA's 2024 ARCSIX (Arctic Radiation-Cloud-Aerosol-Surface Interaction Experiment) field campaign. I will also discuss emerging satellite remote sensing approaches and recent work on polar mixed‑phase cloud thinning as a potential climate intervention strategy. I will conclude by briefly reflecting on career lessons learned that may be helpful for current graduate students, including managing research transitions, building diverse mentoring networks, and approaching complex scientific problems strategically.
Lauren Zamora is an Associate Research Scientist at the Earth System Science Interdisciplinary Center, University of Maryland, College Park. Since 2017, she has also been a cooperative agreement scientist partnering through the University of Maryland with NASA Goddard Space Flight Center. She obtained her PhD from the University of Miami Rosenstiel School in 2010 after studying atmospheric aerosol nutrient deposition to the ocean and its biogeochemical impacts. Her current work combines satellite observations, fieldwork, and modeling to investigate how aerosols affect cloud formation in polar regions. Dr. Zamora is on the leadership team for the NASA Arctic Radiation-Cloud-Aerosol-Surface Interaction EXperiment (ARCSIX) aircraft campaign and co-leads the QuIESCENT international scientific group, which coordinates global research efforts to quantify Arctic aerosol-cloud interactions.
Jan 21: SPECIAL ATM & OCE FACULTY PRESENTATION SERIES
Dr. Roland Romeiser
Department of Ocean Sciences, Rosenstiel School
SAR Remote Sensing of the Ocean
A General Overview and Update on Recent Projects
Recording Available at COMPASS ON DEMAND
The concept of synthetic aperture radar for high-resolution imaging of the Earth's surface was developed in the 1950s and tested on a first satellite in December 1964. Today, six decades later, we have about 100 operational SAR satellites available to acquire sub-meter-resolution images at almost any point on Earth within hours and to obtain repeated lower-resolution images of large land, coastal, and polar regions every few days. These capabilities, combined with advanced data processing and interpretation techniques and the fact that microwave radars can operate at day and night and see through clouds, have made the SAR satellites attractive and indispensable for a wide range of applications.
This seminar in the COMPASS Special ATM & OCE Faculty Presentation Series will begin with an overview of the history of SAR and of the presenter's own contributions to the field of ocean remote sensing in the last 40 years. The second part will be a sequel to the presentation from October 3, 2018. It was demonstrated how we can reprocess spotlight-mode SAR images into short video-like image sequences and use the theoretical dispersion relation of ocean waves as a filter to separate linear SAR signatures of moving waves from other contributions. The filtered wave signatures can then be inverted into waveheight spectra by applying a simple linear modulation transfer function. Now the latest version of our algorithm can account for changes of the dispersion relation in shallow water and in the presence of surface currents and estimate water depths and current vectors as byproducts of the filtering process. This technique has been used in the analysis of marine radar (ship radar) image sequences for many years, but the SAR-derived time series are too short for a full Fourier analysis in the time domain and required some new solutions, which will be discussed. Last but not least, examples of our team's contributions to the recent large collaborative project "NOPP Hurricane Coastal Impacts" will be shown.
Jan 28: Dr. Alexander Soloviev
Dept of Marine and Environmental Sciences, Halmos College of Arts and Sciences
Nova Southeastern University's Oceanographic Center, Dania Beach, FL
"Hidden" Upwelling on the Southeast Florida Shelf
Recording Available at COMPASS ON DEMAND
Classical wind-driven coastal upwelling is predominantly observed along the eastern ocean boundaries, such as the California Shelf. Along western ocean boundaries, including the Southeast Florida Shelf (SFS), wind-driven upwelling typically occurs only during extreme wind events, such as hurricanes. However, an alternative and potentially powerful form of coastal upwelling exists along western boundaries. This upwelling does not generally penetrate the strong near-surface stratification of the summertime coastal ocean but can substantially modify temperature and nutrient conditions within the benthic boundary layer, with important ecological consequences. In recent literature, this phenomenon has been termed "hidden" upwelling. Evidence for hidden upwelling on the SFS is supported by numerous diver observations of episodic cooling events confined to reef depths, occurring in the absence of any detectable surface signature. While western boundary currents are known to generate upwelling through multiple physical mechanisms, the dominant processes underlying hidden upwelling on the SFS have not been fully resolved. Analysis of 25 years of coastal ocean observations from acoustic Doppler current profiler (ADCP) moorings, supplemented by recent measurements from a Wirewalker and a Slocum 3 Glider equipped with an ADCP, helps to identify the dominant mechanisms driving hidden upwelling along the SFS. Because coral reef benthic communities are highly sensitive to changes in temperature and nutrient supply associated with coastal upwelling, this work provides new insight into subsurface physical drivers of reef variability and has direct relevance for coral reef management on the SFS.
Feb 04: SPECIAL ATM & OCE FACULTY PRESENTATION SERIES
Dr. Joseph Prospero
Professor Emeritus, Department of Atmospheric Sciences, Rosenstiel School
My Life Chasing Dust Over the Global Oceans
Most graduate students begin their studies with a hazy idea of where their studies might take them. Often, upon graduation, they find it necessary to adapt. That was true for me. I acquired a Ph.D. (Princeton, 1963) in nuclear chemistry and nuclear spectroscopy. In my fourth year I concluded that the field was approaching a dead-end and that I would have to switch to another field. By pure chance at a party, I learned of an opportunity to lead a project at the University of Miami "marine school". Despite knowing nothing about the school, I interviewed and was hired in 1963. Unfortunately, the project failed. Here I describe how my career evolved after that failure. In this presentation I review my journey and some of the science accomplished along the way.
I do not intend to present a survey of my research but rather to describe the context in which my program evolved. In 1965, I focused on aerosols in the ocean environment which at that time was relatively unexplored. My ultimate goal was to develop a global picture of marine aerosol concentrations and properties and their temporal and spatial distributions over the oceans. To this end and with a strong supporting group, I worked to create a global network of sampling stations on islands in the Atlantic, Pacific and Indian Oceans. Our primary interest was mineral dust because of its strong link to climate as a causative factor and also its role in ocean chemistry. However, we also measured many other species (e.g., nitrate, nss-sulfate, MSA, etc.) and also many important elements (e.g., Fe). These data were spatially integrated using a variety of remote sensing instruments, both ground-based and aboard satellites. These data are widely used to validate satellite aerosol retrieval algorithms. Participation in major field campaigns enabled synoptic observations and large-scale integration. Curiously, these data are now 25 to 50 years old but they remain the only synoptic ocean aerosol measurements. There is a clear need for the synoptic measurement of aerosols over the oceans because of the great variability in their concentrations and composition. Finally, as the result of this program, we (i.e., Cassie Gaston) have acquired an archive of over 60,000 filters that are available for study.
Feb 11: STUDENT SEMINARS
Evan Wellmeyer (ATM)
Constraining Regional Projections of Precipitation Change With Machine Learning
Regional precipitation change remains a major source of uncertainty in climate projections. We develop a machine learning framework that learns a spatially structured mapping from historical precipitation climatology (PR) to precipitation change per degree of global warming (dPdK), enabling regional responses to be conditioned on present day mean state structure. We train a probabilistic neural network (NN) ensemble on three HadGEM perturbed-parameter ensembles (PPEs) and benchmark against ensemble mean, Gaussian-weighted model selection, and gridpoint regression baselines. In within-PPE tests, the NN reduces RMSE relative to the PPE mean by a median of 28%, with maximum reductions of 46% globally and 48% over land. To improve cross-model transfer, we use a prior–residual formulation in which the NN conditions on PR and a physically motivated prior dPdK (a weighted multi-model mean) and predicts the residual. Fine-tuning on CMIP6 response patterns improves performance for held-out models, though skill is constrained by the limited size of the training pool. Applied to 44 coupled CMIP6 models, this approach reduces RMSE by 7.5% on a held-out model (GFDL-ESM4) over the CMIP6 multi-model mean. Finally, we apply the fine-tuned ensemble to observations, producing observation-conditioned estimates of regional precipitation sensitivity with spatially resolved uncertainty.
Susan Harrison (OCE)
Feb 18: Dr. Andrew Dessler
Texas Center for Extreme Weather, Texas A&M University, College Station
Guest of the Department of Atmospheric Sciences
Climate Change, Renewables, and the Cost of Electricity
Electricity is one of the most important enablers of our modern lifestyle. Many Americans live in regions where electricity markets set prices, and this talk explains why renewable energy and battery storage reduce costs in these regions. To do this, we analyze ERCOT and CAISO market data to quantify the growing cost burden from climate change as well as the savings due to renewable energy and batteries. We show that renewables and energy storage deliver measurable savings by lowering prices, but climate change is simultaneously driving both cost and demand upward.
Feb 25: Chanyoung Park
Department of Atmospheric Sciences, Rosenstiel School
(1-hour ATM student seminar)
Mar 04: POSTER SESSION
Mar 11: NO SEMINAR (Spring Recess)
Mar 18: STUDENT SEMINARS
Theresia Phoa (ATM)
Lily Johnston (ATM)
Mar 25: STUDENT SEMINARS
Sophia DiPietro (ATM)
Phoebe Scharle (OCE)
Claire Fandel (OCE)
Apr 01: James Christie
Department of Atmospheric Sciences, Rosenstiel School
(1-hour ATM student seminar)
Apr 08: Madeleine Dawson
Department of Ocean Sciences, Rosenstiel School
(1-hour OCE student seminar)
Apr 15: Alexis Wilson
Department of Atmospheric Sciences, Rosenstiel School
(1-hour ATM student seminar)
Apr 22: Dr. Milan Curcic
Department of Ocean Sciences, Rosenstiel School
Wave Action Balance in Strongly Varying Currents
Wave action balance is the fundamental equation behind spectral wave models that are used for global wave forecasting. Originated in Whitham's [1965] variational method and generalized by Bretherton & Garrett [1968] to propagation over slowly-varying currents, wave action conservation has since been taken as accurate within the first order of the relative variation in the current field. Slow variation of currents has been assumed by most wave models to date. In this work, we analyze an expanded form of the wave action balance that includes 1st-order effects of current gradients within the wavetrain (this term was presented by Bretherton & Garrett but neglected as small). First, based on a month-long submesoscale (150-m resolution) simulation of ocean circulation, we demonstrate that the contribution of unresolved current gradients to the wave action tendency, at the 1st order, is ~6 times larger than the wave strain / convergence by wave grid-resolved currents, and ~1.2 times larger than the propagation term itself. Second, we perform numerical simulations of wave propagation over the 150-m resolution surface currents and quantify the adjustment of the wave field to the circulation. Not suprisingly, strong current gradients act to boost wave action gradients such that the propagation term becomes as dominant as the current strain terms. Although there has been increasing evidence in the past decade of strong impacts of the resolved currents on the wave fields, we believe that this is the first quantitative assessment of subgrid-scale current gradients on the wave field. We expect this effect to be important for the accuracy of swell propagation over large basins, as well as for wave amplification when crossing strong boundary currents.
Apr 29: Dr. Jane Baldwin
Department of Earth System Science, University of California Irvine
Guest of Amy Clement, Department of Atmospheric Sciences
