1,187 research outputs found
Challenges associated with operational modeling of low-oxygen waters in Chesapeake Bay: results from a multiple modeling effort
Skill assessment of multiple hypoxia models in Chesapeake Bay and implications for management decisions
The Chesapeake Bay Program (CBP) has used their coupled watershed-water quality modeling system to develop a set of Total Maximum Daily Loads (TMDLs) for nutrients and sediment in an effort to reduce eutrophication impacts which include decreasing the seasonal occurrence of hypoxia within the Bay. The CBP is now considering the use of a multiple model approach to enhance the confidence in their model projections and to better define uncertainty. This study statistically compares the CBP regulatory model with multiple implementations of the Regional Ocean Modeling System (ROMS) in terms of skill in reproducing monthly profiles of hydrodynamics, nutrients, chlorophyll and dissolved oxygen at ~30 stations throughout the Bay. Preliminary results show that although all the models substantially underestimate stratification throughout the Bay, they all have significant skill in reproducing the mean and seasonal variability of bottom dissolved oxygen. This study demonstrates that multiple community models can be used together to provide independent confidence bounds for management decisions based on CBP model results
Combining observations and numerical model results to improve estimates of hypoxic volume within Chesapeake Bay
Strata Formation on Margins (STRATAFORM) G-60 Site Benthic Boundary Layer Tripod Data Report, November 1996 - January 1997
On hybrid states of two and three level atoms
We calculate atom-photon resonances in the Wigner-Weisskopf model, admitting
two photons and choosing a particular coupling function. We also present a
rough description of the set of resonances in a model for a three-level atom
coupled to the photon field. We give a general picture of matter-field
resonances these results fit into.Comment: 33 pages, 12 figure
Sediment Delivery to a Tidal Marsh Platform Is Minimized by Source Decoupling and Flux Convergence
Sediment supply is a primary factor in determining marsh response to sea level rise and is typically approximated through highâresolution measurements of suspended sediment concentrations (SSCs) from adjacent tidal channels. However, understanding sediment transport across the marsh itself remains limited by discontinuous measurements of SSC over individual tidal cycles. Here, we use an array of optical turbidity sensors to build a longâterm, continuous record of SSC across a marsh platform and adjacent tidal channel. We find that channel and marsh concentrations are correlated (i.e., coupled) within tidal cycles but are largely decoupled over longer time scales. We also find that net sediment fluxes decline to near zero within 10 m of the marsh edge. Together, these results suggest that large sections of the marsh platform receive minimal sediment independent of flooding frequency or channel sediment supply. Marshâcentric, as opposed to channelâcentric, measures of sediment supply may better characterize marsh platform vulnerability
Introduction to the Research Capabilities of the VIMS Coastal Hydrodynamics & Sediment Dynamics (CHSD) Lab
Physical Response of the York River Estuary to Hurricane Isabel
After making landfall on the North Carolina coast on the morning of 18 September 2003, Category 2 Hurricane Isabel tracked northward parallel to and slightly west of the Chesapeake Bay. At Gloucester Point, near the mouth of the York River estuary, strong onshore winds with speeds in excess of 20 mâ
s-1 persisted for over 12 hours and peak winds reached over 40 mâ
s-1, causing a sustained up-estuary wind stress. Storm surge exceeded 2 m throughout most of the lower Chesapeake Bay. A 600 kHz acoustic Doppler current profiler (ADCP), deployed at a depth of 8.5 m off Gloucester Point, provided high-quality data on waves, storm surge, currents, and acoustic backscatter throughout the water column before, during, and after the storm. Pressure and salinity sensors at three additional sites further up the estuary provided information on water surface slope and saltwater excursion up the estuary. A first-order estimate of three terms of the along-channel momentum equation (barotropic pressure gradient, acceleration, and friction) showed that the pressure gradient appeared to be balanced by the wind stress and the acceleration during the storm. The stormâs path and slow speed were the primary causes of the extremely high storm surge relative to past storms in the area.https://scholarworks.wm.edu/vimsbooks/1001/thumbnail.jp
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