Walker Jennifer S.

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Last Name
Walker
First Name
Jennifer S.
ORCID
0000-0002-9650-0776

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  • Article
    Ocean mass, sterodynamic effects, and vertical land motion largely explain US coast relative sea level rise
    (Nature Research, 2021-11-09) Harvey, Thomas C. ; Hamlington, Benjamin D. ; Frederikse, Thomas ; Nerem, R. Steven ; Piecuch, Christopher G. ; Hammond, William C. ; Blewitt, Geoffrey ; Thompson, Philip R. ; Bekaert, David P. S. ; Landerer, Felix ; Reager, John T. ; Kopp, Robert E. ; Chandanpurkar, Hrishikesh A. ; Fenty, Ian ; Trossman, David S. ; Walker, Jennifer S. ; Boening, Carmen
    Regional sea-level changes are caused by several physical processes that vary both in space and time. As a result of these processes, large regional departures from the long-term rate of global mean sea-level rise can occur. Identifying and understanding these processes at particular locations is the first step toward generating reliable projections and assisting in improved decision making. Here we quantify to what degree contemporary ocean mass change, sterodynamic effects, and vertical land motion influence sea-level rise observed by tide-gauge locations around the contiguous U.S. from 1993 to 2018. We are able to explain tide gauge-observed relative sea-level trends at 47 of 55 sampled locations. Locations where we cannot explain observed trends are potentially indicative of shortcomings in our coastal sea-level observational network or estimates of uncertainty.
  • Article
    Pollen geochronology from the Atlantic Coast of the United States during the last 500 years
    (MDPI, 2021-01-31) Christie, Margaret A. ; Bernhardt, Christopher E. ; Parnell, Andrew C. ; Shaw, Timothy ; Khan, Nicole S. ; Corbett, D. Reide ; García-Artola, Ane ; Clear, Jennifer ; Walker, Jennifer S. ; Donnelly, Jeffrey P. ; Hasse, Tobias R. ; Horton, Benjamin P.
    Building robust age–depth models to understand climatic and geologic histories from coastal sedimentary archives often requires composite chronologies consisting of multi-proxy age markers. Pollen chronohorizons derived from a known change in vegetation are important for age–depth models, especially those with other sparse or imprecise age markers. However, the accuracy of pollen chronohorizons compared to other age markers and the impact of pollen chronohorizons on the precision of age–depth models, particularly in salt marsh environments, is poorly understood. Here, we combine new and published pollen data from eight coastal wetlands (salt marshes and mangroves) along the Atlantic Coast of the United States (U.S.) from Florida to Connecticut to define the age and uncertainty of 17 pollen chronohorizons. We found that 13 out of 17 pollen chronohorizons were consistent when compared to other age markers (radiocarbon, radionuclide 137Cs and pollution markers). Inconsistencies were likely related to the hyperlocality of pollen chronohorizons, mixing of salt marsh sediment, reworking of pollen from nearby tidal flats, misidentification of pollen signals, and inaccuracies in or misinterpretation of other age markers. Additionally, in a total of 24 models, including one or more pollen chronohorizons, increased precision (up to 41 years) or no change was found in 18 models.