Frederikse Thomas

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Frederikse
First Name
Thomas
ORCID
0000-0002-5024-0163

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  • Article
    Local and remote forcing of interannual sea‐level variability at Nantucket Island
    (American Geophysical Union, 2022-06-07) Wang, Ou ; Lee, Tong ; Piecuch, Christopher G. ; Fukumori, Ichiro ; Fenty, Ian ; Frederikse, Thomas ; Menemenlis, Dimitris ; Ponte, Rui M. ; Zhang, Hong
    The relative contributions of local and remote wind stress and air-sea buoyancy forcing to sea-level variations along the East Coast of the United States are not well quantified, hindering the understanding of sea-level predictability there. Here, we use an adjoint sensitivity analysis together with an Estimating the Circulation and Climate of the Ocean (ECCO) ocean state estimate to establish the causality of interannual variations in Nantucket dynamic sea level. Wind forcing explains 67% of the Nantucket interannual sea-level variance, while wind and buoyancy forcing together explain 97% of the variance. Wind stress contribution is near-local, primarily from the New England shelf northeast of Nantucket. We disprove a previous hypothesis about Labrador Sea wind stress being an important driver of Nantucket sea-level variations. Buoyancy forcing, as important as wind stress in some years, includes local contributions as well as remote contributions from the subpolar North Atlantic that influence Nantucket sea level a few years later. Our rigorous adjoint-based analysis corroborates previous correlation-based studies indicating that sea-level variations in the subpolar gyre and along the United States northeast coast can both be influenced by subpolar buoyancy forcing. Forward perturbation experiments further indicate remote buoyancy forcing affects Nantucket sea level mostly through slow advective processes, although coastally trapped waves can cause rapid Nantucket sea level response within a few weeks.
  • 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
    Origin of interannual variability in global mean sea level
    (National Academy of Sciences, 2020-06-08) Hamlington, Benjamin D. ; Piecuch, Christopher G. ; Reager, John T. ; Chandanpurkar, Hrishikesh A. ; Frederikse, Thomas ; Nerem, R. Steven ; Fasullo, John T. ; Cheon, Se-Hyeon
    The two dominant drivers of the global mean sea level (GMSL) variability at interannual timescales are steric changes due to changes in ocean heat content and barystatic changes due to the exchange of water mass between land and ocean. With Gravity Recovery and Climate Experiment (GRACE) satellites and Argo profiling floats, it has been possible to measure the relative steric and barystatic contributions to GMSL since 2004. While efforts to “close the GMSL budget” with satellite altimetry and other observing systems have been largely successful with regards to trends, the short time period covered by these records prohibits a full understanding of the drivers of interannual to decadal variability in GMSL. One particular area of focus is the link between variations in the El Niño−Southern Oscillation (ENSO) and GMSL. Recent literature disagrees on the relative importance of steric and barystatic contributions to interannual to decadal variability in GMSL. Here, we use a multivariate data analysis technique to estimate variability in barystatic and steric contributions to GMSL back to 1982. These independent estimates explain most of the observed interannual variability in satellite altimeter-measured GMSL. Both processes, which are highly correlated with ENSO variations, contribute about equally to observed interannual GMSL variability. A theoretical scaling analysis corroborates the observational results. The improved understanding of the origins of interannual variability in GMSL has important implications for our understanding of long-term trends in sea level, the hydrological cycle, and the planet’s radiation imbalance.
  • Article
    Understanding of contemporary regional sea-level change and the implications for the future
    (American Geophysical Union, 2020-04-17) Hamlington, Benjamin D. ; Gardner, Alex S. ; Ivins, Erik ; Lenaerts, Jan T. M. ; Reager, John T. ; Trossman, David S. ; Zaron, Edward D. ; Adhikari, Surendra ; Arendt, Anthony ; Aschwanden, Andy ; Beckley, Brian D. ; Bekaert, David P. S. ; Blewitt, Geoffrey ; Caron, Lambert ; Chambers, Don P. ; Chandanpurkar, Hrishikesh A. ; Christianson, Knut ; Csatho, Beata ; Cullather, Richard I. ; DeConto, Robert M. ; Fasullo, John T. ; Frederikse, Thomas ; Freymueller, Jeffrey T. ; Gilford, Daniel M. ; Girotto, Manuela ; Hammond, William C. ; Hock, Regine ; Holschuh, Nicholas ; Kopp, Robert E. ; Landerer, Felix ; Larour, Eric ; Menemenlis, Dimitris ; Merrifield, Mark ; Mitrovica, Jerry X. ; Nerem, R. Steven ; Nias, Isabel J. ; Nieves, Veronica ; Nowicki, Sophie ; Pangaluru, Kishore ; Piecuch, Christopher G. ; Ray, Richard D. ; Rounce, David R. ; Schlegel, Nicole‐Jeanne ; Seroussi, Helene ; Shirzaei, Manoochehr ; Sweet, William V. ; Velicogna, Isabella ; Vinogradova, Nadya ; Wahl, Thomas ; Wiese, David N. ; Willis, Michael J.
    Global sea level provides an important indicator of the state of the warming climate, but changes in regional sea level are most relevant for coastal communities around the world. With improvements to the sea‐level observing system, the knowledge of regional sea‐level change has advanced dramatically in recent years. Satellite measurements coupled with in situ observations have allowed for comprehensive study and improved understanding of the diverse set of drivers that lead to variations in sea level in space and time. Despite the advances, gaps in the understanding of contemporary sea‐level change remain and inhibit the ability to predict how the relevant processes may lead to future change. These gaps arise in part due to the complexity of the linkages between the drivers of sea‐level change. Here we review the individual processes which lead to sea‐level change and then describe how they combine and vary regionally. The intent of the paper is to provide an overview of the current state of understanding of the processes that cause regional sea‐level change and to identify and discuss limitations and uncertainty in our understanding of these processes. Areas where the lack of understanding or gaps in knowledge inhibit the ability to provide the needed information for comprehensive planning efforts are of particular focus. Finally, a goal of this paper is to highlight the role of the expanded sea‐level observation network—particularly as related to satellite observations—in the improved scientific understanding of the contributors to regional sea‐level change.
  • Article
    The dominant global modes of recent internal sea level variability
    (American Geophysical Union, 2019-03-21) Hamlington, Benjamin D. ; Cheon, Se-Hyeon ; Piecuch, Christopher G. ; Karnauskas, Kristopher B. ; Thompson, Philip R. ; Kim, Kwang-Yul ; Reager, John T. ; Landerer, Felix ; Frederikse, Thomas
    The advances in the modern sea level observing system have allowed for a new level of knowledge of regional and global sea level in recent years. The combination of data from satellite altimeters, Gravity Recovery and Climate Experiment (GRACE) satellites, and Argo profiling floats has provided a clearer picture of the different contributors to sea level change, leading to an improved understanding of how sea level has changed in the present and, by extension, may change in the future. As the overlap between these records has recently extended past a decade in length, it is worth examining the extent to which internal variability on timescales from intraseasonal to decadal can be separated from long‐term trends that may be expected to continue into the future. To do so, a combined modal decomposition based on cyclostationary empirical orthogonal functions is performed simultaneously on the three data sets, and the dominant shared modes of variability are analyzed. Modes associated with the trend, seasonal signal, El Niño–Southern Oscillation, and Pacific decadal oscillation are extracted and discussed, and the relationship between regional patterns of sea level change and their associated global signature is highlighted.