Now showing 1 - 5 of 5
- ItemBlock-structured, equal-workload, multi-grid-nesting interface for the Boussinesq wave model FUNWAVE-TVD (Total Variation Diminishing)(Geoscientific Model Development, 2022-07-18) Choi, Young-Kwang; Shi, Fengyan; Malej, Matt; Smith, Jane M.; Kirby, James T.; Grilli, Stephan T.We describe the development of a block-structured, equal-CPU-load (central processing unit), multi-grid-nesting interface for the Boussinesq wave model FUNWAVE-TVD (Fully Nonlinear Boussinesq Wave Model with Total Variation Diminishing Solver). The new model framework does not interfere with the core solver, and thus the core program, FUNWAVE-TVD, is still a standalone model used for a single grid. The nesting interface manages the time sequencing and two-way nesting processes between the parent grid and child grid with grid refinement in a hierarchical manner. Workload balance in the MPI-based (message passing interface) parallelization is handled by an equal-load scheme. A strategy of shared array allocation is applied for data management that allows for a large number of nested grids without creating additional memory allocations. Four model tests are conducted to verify the nesting algorithm with assessments of model accuracy and the robustness in the application in modeling transoceanic tsunamis and coastal effects.
- ItemSurface impacts of large offshore wind farms(Environmental Research Letters, 2022-05-25) Golbazi, Maryam; Archer, Cristina L.; Alessandrini, StefanoFuture offshore wind farms around the world will be built with wind turbines of size and capacity never seen before (with diameter and hub height exceeding 150 and 100 m, respectively, and rated power exceeding 10 MW). Their potential impacts at the surface have not yet been studied. Here we conduct high-resolution numerical simulations using a mesoscale model with a wind farm parameterization and compare scenarios with and without offshore wind farms equipped with these 'extreme-scale' wind turbines. Wind speed, turbulence, friction velocity, and sensible heat fluxes are slightly reduced at the surface, like with conventional wind turbines. But, while the warming found below the rotor in stable atmospheric conditions extends to the surface with conventional wind turbines, with extreme-scale ones it does not reach the surface, where instead minimal cooling is found. Overall, the surface meteorological impacts of large offshore wind farms equipped with extreme-scale turbines are statistically significant but negligible in magnitude.
- ItemPopulation Dynamics of Common Nearshore Forage Fishes in the Delaware Inland Bays, USA(Estuaries and Coasts, 2022-03-13) McGowan, Andrew T.; Hale, Edward A.; Bartow, Dennis H.; Greco, MichaelIn the Mid-Atlantic, four species of forage fish, Menidia menidia (Atlantic Silverside), Fundulus heteroclitus (Mummichog), Fundulus majalis (Striped Killifish), and Cyprinodon variegatus (Sheepshead Minnow), account for a large proportion of fish abundance in estuarine environments and are important food sources for state and federally managed predatory species. The population dynamics of these species are poorly understood, and factors affecting their populations are largely unclear or unknown. Seine samples were collected in the Delaware Inland Bays over 9 years (2011–2019), with indices and trends in abundance, as well as climatic and biotic drivers of population changes investigated at both combined estuary and individual bay scales. Average interannual decreases in abundance for all four species at the combined estuary scale ranged between 31.9 and 69.2%, while increases ranged between 65.9 and 178.6%, indicating the extreme variability these species show between years. Standardized models of abundance demonstrated long-term declines in abundance for Mummichog and Sheepshead Minnow at both the combined estuary and individual bay scales. Spring discharge affected Mummichog and Sheepshead Minnow abundance, and Sheepshead Minnow showed a strong negative correlation with Summer Flounder abundance. These data quantify the variability in abundance for an important portion of the forage base in Mid-Atlantic estuaries and should be considered as fisheries management shifts away from single-species approaches and recognizes the forage needs of managed species. Results indicate that even commonly encountered species can consistently vary through time and emphasize the need to examine other important but poorly studied forage species.
- ItemMarshaling ports required to meet US policy targets for offshore wind power(Energy Policy, 2022-02-16) Parkison, Sara B.; Kempton, WillettWe analyze infrastructure needed for offshore wind power targets set by U.S. state and federal policies—specifically, manufacturing, vessels, and offshore wind ports. By examining cost-competitive turbine and project sizes and infrastructure challenges, we identify marshaling ports as a key bottleneck. Through elicitation of requirements from supply chain, port, and vessel experts, we identify the necessary attributes for marshaling ports and calculate the area needed to meet policy targets. US marshaling ports are currently insufficient to meet either state or federal power targets. We calculate state commitments from state contracts and policies: in sum, 40 GW by 2040. Federal targets from the Biden Administration are 30 GW by 2030 and 110 GW by 2050. Either target yields more demand for marshaling area than is currently available or planned. The shortage of marshaling area supply has incorrectly been attributed to lack of suitable U.S. locations. Instead, we attribute it to developers having built ports to support early, smaller projects, and having located them to incentivize state power contracts rather than developing ports for long-term, large-scale, and economically-efficient use. Additional land suitable for marshaling ports exists, but it requires commitment from port authorities and port investors to develop it for this purpose.
- ItemVariability and Dynamics of Along-Shore Exchange on the West Antarctic Peninsula (WAP) Continental Shelf(Journal of Geophysical Research: Oceans, 2022-01-31) Wang, Xin; Moffat, Carlos; Dinniman, Michael S.; Klinck, John M.; Sutherland, David A.; Aguiar-González, BorjaThe continental shelf of the West Antarctic Peninsula (WAP) is characterized by strong along-shore hydrographic gradients resulting from the distinct influences of the warm Bellingshausen Sea to the south and the cold Weddell Sea water flooding Bransfield Strait to the north. These gradients modulate the spatial structure of glacier retreat and are correlated with other physical and biochemical variability along the shelf, but their structure and dynamics remain poorly understood. Here, the magnitude, spatial structure, seasonal-to-interannual variability, and driving mechanisms of along-shore exchange are investigated using the output of a high-resolution numerical model and with hydrographic data collected in Palmer Deep. The analyses reveal a pronounced seasonal cycle of along-shore transport, with a net flux (7.0 × 105 m3/s) of cold water toward the central WAP (cWAP) in winter, which reverses in summer with a net flow (5.2 × 105 m3/s) of Circumpolar Deep Water (CDW) and modified CDW (mCDW) toward Bransfield Strait. Significant interannual variability is found as the pathway of a coastal current transporting Weddell-sourced water along the WAP shelf is modulated by wind forcing. When the Southern Annual Mode (SAM) is positive during winter, stronger upwelling-favorable winds dominate in Bransfield Strait, leading to offshore advection of the Weddell-sourced water. Negative SAM leads to weaker upwelling- or downwelling-favorable winds and enhanced flooding of the cWAP with cold water from Bransfield Strait. This process can result in significant (0.5°C below 200 m) cooling of the continental shelf around Palmer Station, highlighting that along-shore exchange is critical in modulating the hydrographic properties along the WAP. Plain Language Summary: The melting of glaciers and the structure of ecosystems along the West Antarctic Peninsula have been influenced by the local temperature and salinity patterns. Our understanding of what controls the spatial structure and temporal variability of these gradients is limited. In this study, we analyze output from a state-of-the-art numerical model and find that there is strongly seasonal and interannual variability in the along-shore exchange processes that control those gradients. The interannual variability of the along-shore exchange is related to the local winds. As the wind conditions vary in response to hemispheric-scale climate processes, the amount of cold water flowing into the central West Antarctic Peninsula from Bransfield Strait varies interannually. We show this is a key process in the evolution of ocean properties in the West Antarctic Peninsula continental shelf.