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Ali Chase

Postdoctoral Scholar

Email

achase@apl.uw.edu

Phone

206-543-7836

Biosketch

Ali Chase joined APL-UW in the summer of 2020 as a Washington Research Foundation Postdoctoral Fellow. She is collaborating with oceanographers Kyla Drushka and Peter Gaube as a member of the (Sub)mesoscale Group on several projects related to observing phytoplankton in the open ocean using optics and linking phytoplankton community composition to physical ocean features. Before beginning postdoc research in the summer of 2020, Chase earned a PhD at the University of Maine. Working there in the MISC Lab with Emmanuel Boss and Lee Karp-Boss, her dissertation was on methods to observe phytoplankton in the open ocean using optics, flow cytometry, and pigments.

During postdoc studies, Chase is working on algorithm development to detect phytoplankton community composition from ocean color satellite measurements. The approach to this challenge has two components: 1) estimate phytoplankton accessory pigment concentrations from hyperspectral remote-sensing reflectance spectra, and 2) use phytoplankton group information from imaging-in-flow cytometry to determine predictive relationships via neural networks between phytoplankton communities and ocean environmental parameters.

Education

B.A. Geology and Environmental Studies, Bowdoin College, 2009

M.S. Oceanography, University of Maine, 2014

Ph.D. Oceanography, University of Maine, 2020

Ali Chase's Website

http://alichase.com

Publications

2000-present and while at APL-UW

Assessing the skill of a high-resolution marine biophysical model using geostatistical analysis of mesoscale ocean chlorophyll variability from field observations and remote sensing

Eveleth, R., D.M. Glover, M.C. Long, I.D. Lima, A.P. Chase, and S.C. Doney, "Assessing the skill of a high-resolution marine biophysical model using geostatistical analysis of mesoscale ocean chlorophyll variability from field observations and remote sensing," Front. Mar. Sci., 8, doi:10.3389/fmars.2021.612764, 2021.

More Info

6 Apr 2021

High-resolution ocean biophysical models are now routinely being conducted at basin and global-scale, opening opportunities to deepen our understanding of the mechanistic coupling of physical and biological processes at the mesoscale. Prior to using these models to test scientific questions, we need to assess their skill. While progress has been made in validating the mean field, little work has been done to evaluate skill of the simulated mesoscale variability. Here we use geostatistical 2-D variograms to quantify the magnitude and spatial scale of chlorophyll a patchiness in a 1/10th-degree eddy-resolving coupled Community Earth System Model simulation. We compare results from satellite remote sensing and ship underway observations in the North Atlantic Ocean, where there is a large seasonal phytoplankton bloom. The coefficients of variation, i.e., the arithmetic standard deviation divided by the mean, from the two observational data sets are approximately invariant across a large range of mean chlorophyll a values from oligotrophic and winter to subpolar bloom conditions. This relationship between the chlorophyll a mesoscale variability and the mean field appears to reflect an emergent property of marine biophysics, and the high-resolution simulation does poorly in capturing this skill metric, with the model underestimating observed variability under low chlorophyll a conditions such as in the subtropics.

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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