Nancy Louise Williams

Nancy Louise Williams
University of South Florida | USF · College of Marine Science

Ph.D. Ocean Ecology and Biogeochemistry, Oregon State University; M.S. Oceanography, University of Washington; B.S. Chemistry and Marine Science, University of Miami

About

31
Publications
7,323
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828
Citations
Introduction
I am an Assistant Professor at the University of South Florida College of Marine Science in St. Petersburg, Florida, USA. I use data from autonomous biogeochemical sensors and Earth System Model output to study the ocean's role in the global carbon cycle.
Additional affiliations
August 2019 - present
University of South Florida
Position
  • Professor (Assistant)
May 2018 - present
National Oceanic and Atmospheric Administration
Position
  • PostDoc Position
March 2015 - May 2018
Oregon State University
Position
  • Research Assistant
Education
March 2015 - June 2018
Oregon State University
Field of study
  • Chemical Oceanography
September 2011 - March 2015
University of Washington Seattle
Field of study
  • Oceanography
August 2004 - May 2008
University of Miami
Field of study
  • Marine Science and Chemistry

Publications

Publications (31)
Preprint
Remote, harsh conditions of the Southern Ocean challenge our ability to observe the region's influence on the climate system. Southern Ocean air‐sea CO2 flux estimates have significant uncertainty due to the reliance on limited ship‐dependent observations in combination with satellite‐based and interpolated data products. We utilize a new approach,...
Article
Full-text available
The Southern Ocean south of 30° S represents only one-third of the total ocean area, yet absorbs half of the total ocean anthropogenic carbon and over two-thirds of ocean anthropogenic heat. In the past, the Southern Ocean has also been one of the most sparsely measured regions of the global ocean. Here we use pre-2005 ocean shipboard measurements...
Article
Full-text available
We advance a simple framework based on “time of detection” for estimating the observational needs of studies assessing climate changes amidst natural variability and apply it to several examples related to ocean acidification. This approach aims to connect the Global Ocean Acidification Observing Network “weather” and “climate” data quality thresho...
Article
Full-text available
Biogeochemical Argo floats, profiling to 2,000-m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic...
Article
Full-text available
This work presents two new methods to estimate oceanic alkalinity (AT), dissolved inorganic carbon (CT), pH, and pCO2 from temperature, salinity, oxygen, and geolocation data. “CANYON-B” is a Bayesian neural network mapping that accurately reproduces GLODAPv2 bottle data and the biogeochemical relations contained therein. “CONTENT” combines and ref...
Article
Full-text available
The Southern Ocean is highly under-sampled for the purpose of assessing total carbon uptake and its variability. Since this region dominates the mean global ocean sink for anthropogenic carbon, understanding temporal change is critical. Underway measurements of pCO2 collected as part of the Drake Passage Time-series (DPT) program that began in 2002...
Article
Full-text available
We have taken advantage of the release of version 2 of the Global Data Analysis Project data product(Olsen et al. 2016) to refine the locally interpolated alkalinity regression (LIAR) code for global estimation of total titration alkalinity of seawater (AT), and to extend the method to also produce estimates of nitrate (N)and in situ pH (total scal...
Article
Full-text available
The Southern Ocean is highly under-sampled for the purpose of assessing total carbon uptake and its variability. Since this region dominates the mean global ocean sink for anthropogenic carbon, understanding temporal change is critical. Underway measurements of pCO2 collected as part of the Drake Passage Time-series (DPT) program that began in 2002...
Article
The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program has begun deploying a large array of biogeochemical sensors on profiling floats in the Southern Ocean. As of February 2016, 86 floats have been deployed. Here the focus is on 56 floats with quality controlled and adjusted data that have been in the water at least 6 mon...
Poster
Full-text available
A summary of and motivation for ”Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH: An uncertainty analysis” including a description of SOCCOM floats for a more general audience of climate scientists.
Article
More than 74 biogeochemical profiling floats that measure water column pH, oxygen, nitrate, fluorescence, and backscattering at 10-day intervals have been deployed throughout the Southern Ocean. Calculating the surface ocean partial pressure of carbon dioxide (pCO2sw) from float pH has uncertainty contributions from the pH sensor, the alkalinity es...
Article
Full-text available
Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R2 are 0.98 for pH from nitrate (pHN) and 0.97 for pH from oxygen (pHOx) with...
Article
Full-text available
We introduce methods and software for estimating total seawater alkalinity from salinity and any combination of up to four other parameters (potential temperature, apparent oxygen utilization, total dissolved nitrate, and total silicate). The methods return estimates anywhere in the global ocean with comparable accuracy to other published alkalinit...
Article
Full-text available
The Southern Ocean plays a major role in mediating the uptake, transport, and long-term storage of anthropogenic carbon dioxide (CO2) into the deep ocean. Examining the magnitude and spatial distribution of this oceanic carbon uptake is critical to understanding how the earth’s carbon system will react to continued increases in this greenhouse gas....
Conference Paper
Full-text available
The Southern Ocean plays a major role in mediating the uptake, transport, and long-term storage of anthropogenic carbon dioxide (CO2) into the deep ocean. Examining the magnitude and spatial distribution of this oceanic carbon uptake is critical to understanding how the earth’s carbon system will react to continued increases in this greenhouse gas....
Article
Full-text available
The conductivities and densities were measured on 331 samples collected in the South Pacific Ocean during the P18 CLIVAR (Climate Variability and Predictability) cruise. The relative densities (ρ−ρ0) were compared to those determined from the equation of state of seawater. The excess densities (Δρ=ρMeas−ρCalc) ranged from ±0.003 kg m−3 in surface w...

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Projects

Project (1)
Project
http://soccom.princeton.edu/ SOCCOM’s mission is to drive a transformative shift in the scientific and public understanding of the role of the vast Southern Ocean in climate change and biogeochemistry. The goals of the program are to: - Extend sparse Southern Ocean biogeochemical observations by deploying a robotic observing system composed of ~200 autonomous floats that will provide nearly continuous coverage in time and horizontal space over the entire Southern Ocean, as well as vertical coverage deep into the water column. - Using this observational data, analyze and improve a new generation of high resolution earth system models to both increase our understanding of the Southern Ocean’s current workings and make better projections of the future trajectory of the Earth’s climate and biogeochemistry. - Educate a new generation of ocean scientists trained in both ocean observation and simulation, and develop a sophisticated outreach effort to disseminate results to the broadest possible community.