GRAD STUDENTS & POSTDOCS

University of Alaska Fairbanks | University of Washington | Oregon State University

Hauke Schulz

University of Alaska Fairbanks | University of Washington | Oregon State University

Marine mesoscale observation network

Hauke Schulz

Observations for the next generation of climate models

• Next generation of climate simulations aim towards higher spatial resolutions than most dense observing networks and satellite missions.
• Measurements of the ocean, the atmosphere above and their interaction are particularly lacking on these scales.
• Denser networks of observations are needed to develop and evaluate higher resolution simulations

haschulz@uw.edu

Hauke Schulz - University of Washington

Stevens et al. (2019)

Correct representation of mesoscale structures is crucial for an accurate cloudiness in the tropics

• How marine, tropical shallow clouds change with warming remains uncertain
• Recent studies emphasize the influence of mesoscale structures and processes on the cloud fraction
• High resolution simulations of mesoscale extent indicate current challenges in representing the macrophysical characteristics
• Precipitation and their temperature anomalies on the ocean surface are particularly important to represent mesoscale features correctly

Animation of surface temperature in the tropical North Atlantic with frequent cold pools

Capturing mesoscale processes with the help of the sailing community

• Conventional research vessels are expensive and not available at scale
• 300+ sailboats cross the Atlantic each year in close proximity
• Equiping majority of boats with basic meteorological sensors to capture mesoscale variability
• First test phase planned for the coming winter season

haschulz@uw.edu

Hauke Schulz - University of Washington

Curious? Like to get the data for your own project? Contact me!

Shuting Zhai

University of Alaska Fairbanks | University of Washington | Oregon State University

Email: stzhai@uw.edu

Implications of Snowpack Reactive Bromine Production for Arctic Ice Core Bromine Preservation

Email: stzhai@uw.edu

Email: stzhai@uw.edu

Yang Xiang

University of Alaska Fairbanks | University of Washington | Oregon State University

Subtropical gyre nutrient cycling in the upper ocean: Insights from a nutrient-ratio budget method

Yang Xiang*, Paul D. Quay, Rolf E. Sonnerup, Andrea J. Fassbender

yaxiang@uw.edu

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An updated nutrient-ratio budget method

yaxiang@uw.edu

Classic view of surface nutrient budgets

Updated view of surface nutrient budgets

N_exp = N_sup + N_src

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P_exp = P_sup

N_exp = N_sup + N_src

​

P_exp = P_sup

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Quantify the relative importance of P sources and sinks

yaxiang@uw.edu

Station ALOHA

P sources

P sinks

• Importance of vertical inorganic nutrients in P sources

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• Importance of DOM and zooplankton in P sinks

A more quantitative understanding of biological pump

yaxiang@uw.edu

C sinking flux (mol/m²/y)

Depth (m)

Martin Curve

Martin et al., 1987; Siegel et al., 2023

Megan Feddern

University of Alaska Fairbanks | University of Washington | Oregon State University

Non-stationary relationships between climate and fisheries in the California Current and Gulf of Alaska�Megan L. Feddern, Eric J. Ward, Mary Hunsicker, William H. Satterwaite, Curry J. Cunningham

Stationarity: the idea that natural system fluctuate within an unchanging envelope of variability

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Challenge: how do we incorporate physical-biological relationships into forecasts when relationships are varying?

Step 1.  Investigate relationship between atmospheric processes and biologically meaningful climate dynamics that may have contributed to the marine heatwave “era”

Spring PDO - upwelling

Data:

Sea level pressure, SST, PDO, NPGO, upwelling, freshwater discharge, wind

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Analysis:

Bayesian linear model,

Dynamic factor analysis (HMM),

self-organizing maps

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Challenge: how do we incorporate physical-biological relationships into forecasts when relationships are varying?

Data:

Chinook salmon indicator stocks, CalCOFI juvenile fish, Newport hydrologic line, RREAS, groundfish

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Analysis:

Multivariate dynamic linear modelling

Step 3: Identify future forecast ability of best predictive models using alternative measures for cross validation (LFOCV)

Genoa Sullaway

University of Alaska Fairbanks | University of Washington | Oregon State University

Genoa Sullaway

Genoa Sullaway

Genoa Sullaway

Veronica Farrugia Drakard

University of Alaska Fairbanks | University of Washington | Oregon State University

Email: vhfarrugiadrakard@alaska.edu

Alexandra McInturf

University of Alaska Fairbanks | University of Washington | Oregon State University

Alexandra McInturf

Alexandra McInturf

Alexandra McInturf

Samuel May

University of Alaska Fairbanks | University of Washington | Oregon State University

Growing concerns over impacts of salmon hatcheries to wild populations

• Billions of juvenile salmon released each year
• Some hatchery salmon stray into wild populations
• Hatchery fish have fewer offspring
• Hatchery fish are less phenotypically variable
• Are hatchery fish negatively impacting wild population recruitment and resilience?

Release Year

Sockeye

Chum

Pink

Juveniles Released (Millions)

Samuel May

Individual-based simulations to examine evolutionary and demographic effects of strays to wild populations

Results suggest that greater hatchery straying:

• Increases wild recruitment
• Causes rapid introgression of hatchery-origin alleles into wild populations
• Increases synchrony among populations
• Reduces portfolio effects and therefore resilience

May et al. (2023) Evolutionary Applications

github.com/SMay1

Proportion Hatchery-Origin Spawners

Mean Return Day

Generation

Samuel May

Simulations help to explore management options for reducing impacts

• Reduce the number of hatchery fish in the wild
• Reduce release sizes
• Decrease straying
• Change run timing of hatchery fish
• Parameterize with empirical data to predict outcomes of proposed changes

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Thank You!�samay3@alaska.edu�github.com/SMay1

Samuel May

Next: NOAA Leadership

University of Alaska Fairbanks | University of Washington | Oregon State University