Award Abstract # 0961423
Collaborative Research: Estuarine Response to Climate Forcing

NSF Org: OCE
Division Of Ocean Sciences
Recipient: THE PENNSYLVANIA STATE UNIVERSITY
Initial Amendment Date: June 15, 2010
Latest Amendment Date: December 23, 2011
Award Number: 0961423
Award Instrument: Standard Grant
Program Manager: Eric C. Itsweire
OCE
 Division Of Ocean Sciences
GEO
 Directorate for Geosciences
Start Date: June 15, 2010
End Date: May 31, 2015 (Estimated)
Total Intended Award Amount: $322,705.00
Total Awarded Amount to Date: $331,155.00
Funds Obligated to Date: FY 2010 = $322,705.00
FY 2012 = $8,450.00
History of Investigator:
  • Raymond Najjar (Principal Investigator)
Recipient Sponsored Research Office: Pennsylvania State Univ University Park
201 OLD MAIN
UNIVERSITY PARK
PA  US  16802-1503
(814)865-1372
Sponsor Congressional District: 15
Primary Place of Performance: Pennsylvania State Univ University Park
201 OLD MAIN
UNIVERSITY PARK
PA  US  16802-1503
Primary Place of Performance
Congressional District:
15
Unique Entity Identifier (UEI): NPM2J7MSCF61
Parent UEI:
NSF Program(s): PHYSICAL OCEANOGRAPHY,
Integrat & Collab Ed & Rsearch
Primary Program Source: 01001011DB NSF RESEARCH & RELATED ACTIVIT
01001213DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 7969, 9251
Program Element Code(s): 161000, 769900
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

An investigation into the causes of interannual variability in estuarine salinity, stratification and circulation will be conducted using salinity observations, statistical methods, realistic 3-Dimensional hydrodynamic models, and simplified 2-Dimensional numerical models. The overall objective is to quantify interannual variability of estuarine circulation, stratification, and salinity, to explain the physical mechanisms responsible for such variability, and provide an assessment of the likely changes in these metrics in response to future climate change. Observational analysis and 3-Dimensional modeling will be focused on Chesapeake and Delaware Bays, for which (a) extensive salinity databases exist, and (b) a robust numerical model has been developed and validated. Process-oriented modeling studies will be conducted to examine how the estuaries respond to interannual variability in river runoff and shelf salinity, sea-level rise and potential changes in tidal and wind mixing. Multiple model hindcasts will be conducted in which the individual impacts of interannual variability in open-ocean sea level, river flow, shelf salinity, and meteorological forcing are assessed. Statistical models will be applied to the historical salinity data to investigate how salt intrusion length and estuarine stratification vary with river flow, shelf salinity and sea level rise. Projections of future climate impacts on these estuaries will be made by using the regional output of state-of-the art climate models that have been extensively evaluated for the Mid-Atlantic region. General insights into the sensitivity of estuarine physical processes to climate variability and change will be afforded by (1) the differing physics of Chesapeake Bay (partially mixed) and Delaware Bay (well mixed); (2) process oriented and realistic 3-Dimensional modeling studies; and (3) configuration of 2-Dimensional semi-analytical models over a large parameter space of river flow, tidal velocity amplitude, and estuarine geometry.

Intellectual Merit. Much of current estuarine research focuses on relatively short time scales (tidal, weather-related, and seasonal). Little is known of interannual variability in estuarine salinity, stratification, and circulation. The inevitability of sea-level rise and climate change demands a rigorous, physically based approach for quantifying their impacts. This project addresses that need with a collaborative effort between two teams with complementary expertise in numerical modeling, estuarine dynamics, climate change impacts, and time-series analysis.

Broader Impacts. This research project will impact the broader community of estuarine scientists and coastal managers as it will better quantify the potential impacts of climate change on estuarine salinity and stratification, factors that greatly influence water quality and the sustainability of living resources such as oysters and crabs. The long-term model simulations and analysis products will be made available to the Chesapeake and Delaware Bay management communities as they prepare for the impacts of climate change. Results will also be communicated to a broad range of stakeholders, including the general public, through several climate assessment activities underway in the Mid-Atlantic Region. Because the modeling and data analysis approaches developed here can be applied to any estuary, and because we will utilize simplified 2-Dimensional model to provide insights about the potential impacts of climate change on a broad class of estuaries, the impacts of the work extend beyond Chesapeake and Delaware Bays. Educational impacts of the proposal are through the support of graduate and post-doctoral research at the interface of the disciplines of estuarine dynamics and climate change.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Ning, L., M.E. Mann, R. Crane, T. Wagener, R.G. Najjar, and R. Singh "Probabilistic projections of anthropogenic climate change impacts on precipitation for the Mid-Atlantic Region of the United States" Journal of Climate , v.25 , 2012 , p.5273-5291
Ross, A. C.Najjar, R. G.Li, M.Mann, M. E.Ford, S. E.Katz, B. "Sea-level rise and other influences on decadal-scale variations of salinity in a coastal plain estuary" Estuarine Coastal and Shelf Science , v.157 , 2015 , p.79
Schulte, J., Duffy, C., Najjar, R.G. "Geometric and topological approaches to significance testing in wavelet analysis" Nonlinear Processes in Geophysics , v.22 , 2015

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Estuaries are vulnerable to climate change because they can respond to at least three different types of climate change: (1) changes on land from streamflow and associated fluxes of nitrogen, phosphorus, and sediment; (2) changes in the atmosphere and the associated transport of energy, water, and carbon dioxide to and from estuaries; and (3) changes in the ocean from sea-level rise and properties of the open ocean. The overall objectives of this project were to improve our understanding of how estuarine circulation and salinity change from year to year and to apply that knowledge to project how future climate change may influence estuarine circulation and salinity.

 

We developed new statistical techniques to determine the dominant periods of oscillation of streamflow in the Mid-Atlantic Region of the United States. These techniques provide a more accurate assessment of the statistical significance of oscillations. We found that the three main rivers in this region (the Susquehanna, Delaware, and Hudson Rivers) displayed a roughly 20-year oscillation. Furthermore, we found that this oscillation is likely driven by large-scale climate oscillations that originate in the Pacific Ocean (specifically, these are called the El-Niño Southern Oscillation and the Pacific Decadal Oscillation).  Analysis of high streamflow events suggests that they are responding to atmospheric waves generated by rising air masses above the tropical Pacific Ocean.

 

We applied existing statistical methods to determine the factors that govern the long-term variability of salinity in the Delaware Estuary. As in most estuaries, much of the variability in salinity was found to be due to streamflow. After using the statistical methods to remove the influence of streamflow, several locations in the estuary were found to have significant upward trends in salinity that appear to be due to sea-level rise. Winds were also found to influence salinity through vertical and horizontal currents. The results suggest that continued sea-level rise in the future will cause salinity to increase regardless of any change in streamflow.


Last Modified: 09/15/2015
Modified by: Raymond G Najjar

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