(1:00-1:15)
[15]: Coastal Marine Heatwaves Inside and Outside of an Upwelling Bay
Isabelle Cobb★, Ryan WalterDepartment of Physics, ★Speaker
The frequency, intensity, and duration of marine heatwaves (MHWs) have increased over the last several decades, impacting the health of marine ecosystems. MHW characterization in shallow coastal environments remains a challenge due to the lack of long term in-situ measurements and satellite biases near the coastline. In coastal upwelling systems, shallow embayments (upwelling bays) may be particularly susceptible to MHWs due to their retentive nature and could act as sentinel systems for adjacent coastal environments in a warming planet. In this study, we take advantage of nearly two decades of temperature data from inside (using an automated vertical profiling instrument) and outside (using a single-depth mooring) of San Luis Obispo Bay to examine MHW patterns between the two sites. We report MHW metrics across seasonal time scales and compare differences in individuals events across depths, including the effects of coastal upwelling variability. Additionally, we compare upwelling conditions during the initiation and termination of MHWs at both sites. Our results indicate that seasonal temperature climatologies are consistently higher inside the bay, where MHW events tend to occur in greater numbers and intensities. Furthermore, while there is no distinct difference between upwelling patterns at MHW initiation between the sites, measured upwelling anomalies are statistically different for MHW termination between the sites at various depths, highlighting the important role of upwelling forcing in this region. These findings show that small-scale processes can modify MHW risk over small distances in shallow coastal environments, which could lead to improved forecasting and management of valuable coastal resources. |
(1:15-1:30)
[16]: Looking For Very-High Energy Gamma-Rays From a Seyfert Galaxy With VERITAS
Isha Thoreson†★, Jodi Christiansen†Department of Physics, †Frost Support, ★Speaker
The Very Energetic Radiation Imaging Telescope Array System (VERITAS), located in Tucson, Arizona, detects very-high energy gamma-rays. Our research group typically uses gamma-rays to study blazars. For this project, we have been using VERITAS to study a Seyfert galaxy that unexpectedly emits TeV photons. In this talk, I will report the result of our studies. |
(1:30-1:45)
[17]: Ice Melt Plume Dynamics in a Two-Layer Stratified Tank
Jack Agnell1†★, Finn Carpenter1†, Khalid Abbed2†, Ryan Walter1†1 Department of Physics, 2 Marine Sciences, †Frost Support, ★Speaker
Anthropogenic climate change is causing sea ice and ice sheets to melt at unprecedented rates globally. An improved understanding of the mechanisms involved in the ice melt process is essential to predicting the fate of sea ice and the potential impact on global circulation processes. Glaciers and icebergs within fjords are of keen interest because they represent a significant portion of the ice threatened by warming oceans. The Cal Poly Stratified Fluids Tank can emulate the vertical density stratification common in fjord systems, where fresh and brackish water from inland sources and ice melt sits on top of denser seawater intruding into the fjord from the ocean. We performed a series of experiments where we introduced a block of dyed ice to a two-layer vertically stratified system and compared the melt dynamics between systems with differing stratification strengths, determined by the density difference across the interface, and layer heights. We found that a smaller vertical density difference corresponds to a weaker barrier to vertical motions and a decreased melt time, while a larger vertical density difference leads to a stronger barrier, prevents mixing at the interface, and increases the melt time. However, we found that layer thicknesses have the greatest effect on the melt-time because they more directly determine the size of the convection cell formed by the melt-plume, and by extension, the amount of heat transfer at the ice-water interface. Future work will expand the parameter space to include a greater range of densities and layer height thicknesses, and create more complex systems using internal waves, surface waves, and different ice configurations.
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(1:45-2:00)
[18]: Unraveling ecological hotspots using Lagrangian Coherent Structures in the central California Wind Energy Area
Luoma Corbin1†★, Rapha Coutin1†★, Andres Rocha Jayasinha1★, Mazen Idriss2, Casper Pratt2, Leah Hoogstra1, Ian Robbins3, Paul Choboter1, Ryan Walter41 Department of Mathematics, 2 Civil and Environmental Engineering , 3 Department of Biological Sciences, 4 Department of Physics, †Frost Support, ★Speaker
Ocean surface currents are complicated structures governed by processes that operate over a broad range of space and time scales and significantly impact various biological and ecological processes. One area of present and high interest is the newly leased Wind Energy Area (WEA) off the central coast of California, which has been identified for the development of an offshore wind energy farm. Using a decade of data collected by high-frequency radar antennas along the California coast, we present the first ever characterization of surface current patterns and spatiotemporal variability in the WEA. We characterized seasonal patterns in surface current directions and magnitudes to highlight the strong influence of upwelling seasonality. We also assessed seasonal patterns of current trajectories by performing particle tracking both forwards and backwards in time from the WEA to identify the spatial extent of surface current influence. Additionally, through Finite-Time Lyapunov Exponents (FTLEs), which have previously been shown to be linked with ecological hotspots for marine mammals and fisheries, we calculated regions where adjacent fluid particles maximally separate and regions where adjacent fluid particles accumulate. The findings here are critical for environmental assessment, site characterization, and conservation efforts in the vicinity of the WEA.
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(2:00-2:15)
[19]: Solving Ziggu Puzzles Using the Quaternary Gray Code
Madeleine Goertz1†★, Aaron Williams21 Department of Mathematics, 2 Department of Computer Science, Williams College, †Frost Support, ★Speaker
The Ziggu puzzles are a family of physical puzzles designed by Oskar van Deventer. The designs are inspired by Ziggurat, a frameless n-ary puzzle designed by Bram Cohen and Eitan Cher for the 2021 Design Competition. To solve Ziggurat, one fully disassembles the tower of identical pieces.
We investigate solutions to these Ziggu puzzles, which have $p$ pieces that form $m$ mazes.
We encode the state of each puzzle as an quaternary number (i.e., base $4$) with $n=m+1$ digits, where each digit gives the horizontal or vertical position in one maze. We show that the number of states on a shortest solution is $6 \cdot 2^n - 3n - 5$ (OEIS A101946).
There is only one solution of this length, and it is generated from the start configuration by a simple algorithm:
make the leftmost modification that doesn't undo the previous modification.
Replacing "leftmost" with "rightmost" instead generates the unique longest solution that visits all $(3^{n+1} - 1)/2$ states (OEIS A003462).
In this way, Ziggu puzzles can be viewed as $4$-ary, $3$-ary, or $2$-ary puzzles based on how the number of state encodings, valid states, or minimum states grow with each additional maze.
To help solve the puzzle from an arbitrary configuration, we provide $O(n)$-time ranking, comparison, and successor algorithms, which give the state's position along a solution, the relative order of two states, and the next state, respectively.
A preprint is available at arxiv.org/pdf/2411.19291.
This work was initiated at the 2024 NSF SMALL REU at Williams College and supported by NSF Grant DMS-2241623. The speaker would also like to thank the William and Linda Frost Fund in the Bailey College of Science and Mathematics for their generous support. |
(2:15-2:30)
[20]: Convex Lattice $n$-gons with $k\ge3$ Interior Points
Tri Tran★, Elli Sumera★, Dana PaquinDepartment of Mathematics, ★Speaker
We study the geometry of convex lattice $n$-gons with $n$ boundary lattice points and $k\geq 3$ collinear interior lattice points. We describe a process to construct a primitive lattice triangle from an edge of a convex lattice $n$-gon, hence adding one edge in a way so that the number of boundary points increases by $1$, while the number of interior points remains unchanged. We also present the necessary conditions to construct such a primitive lattice triangle, as well as an upper bound for the number of times this is possible. Finally, we apply the previous results to fully classify the positive integers for which there exists a convex $n$-gon with $k$ collinear and non-collinear interior points. |
(2:30-2:45)
[21]: Case study on Flora of San Luis Obispo Through Time and Space art piece
Annica Wu1★, Jeanine Scaramozzino21 CAFES, Plant Science, 2 Bailey College of Science and Math Librarian, ★Speaker
This project explores the intersection of botanical science, art, and community engagement through a case study focused on the flora of Poly Canyon. Over a ten-week period, native and non-native plants were collected weekly as they emerged, creating a temporal snapshot of local biodiversity. These specimens were used to construct a multi-layered botanical art installation that visually represents seasonal changes and plant community dynamics. The piece, titled “Flora of San Luis Obispo Through Time and Space”, is displayed in the Fisher Science Building and continues to evolve as new plant material is added, and is part of Where Science Meets Story, and Community Gets Curious, Spring 2025 Exhibit.
As a fourth-year Plant Science student and Student Curator at the Robert F. Hoover Herbarium, I created this project as both a scientific exploration and an artistic expression, grounded in my experience teaching others how to make art from plant materials. This work is part of the Coastal California Classroom Research Collective (CCCRC) and contributes to a broader effort to make ecological knowledge accessible through interdisciplinary storytelling. Future directions include gathering audience feedback to inform future exhibits and expanding collaborative art-science displays that foster ecological awareness across campus. The group will use this art piece to inform future exhibits.
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