A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element metho...A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.展开更多
Seasonal hypoxia(dissolved oxygen[DO]levels≤2 mg/l)poses a severe threat to coastal ecosystems globally,including the largest estuary in the United States,the Chesapeake Bay.This V-shaped drowned river valley feature...Seasonal hypoxia(dissolved oxygen[DO]levels≤2 mg/l)poses a severe threat to coastal ecosystems globally,including the largest estuary in the United States,the Chesapeake Bay.This V-shaped drowned river valley features shallow flanks,where the deepest waters experience persistently low DO levels typi-cally initiated during the spring and ending in late summer or early autumn.Reports on low DO conditions in the Chesapeake Bay date back over a century[1].Consistent annual records of summer hypoxic conditions have been available since 1985 based on routine data collected through the Chesapeake Bay long-term water quality monitoring program[2].In 2023,the Chesapeake Bay Program(CBP)reported a record low seasonal hypoxic volume(May to October)of 0.58 cubic miles,accord-ing to the Maryland Department of Natural Resources,and 0.52 cubic miles,as reported by the Virginia Institute of Marine Science.Both volumes are considerably below the long-term average of 0.97 cubic miles(Fig.1).展开更多
文摘A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.
基金The research was supported by the U.S.Environmental Protection Agency and the U.S.Geological Survey.
文摘Seasonal hypoxia(dissolved oxygen[DO]levels≤2 mg/l)poses a severe threat to coastal ecosystems globally,including the largest estuary in the United States,the Chesapeake Bay.This V-shaped drowned river valley features shallow flanks,where the deepest waters experience persistently low DO levels typi-cally initiated during the spring and ending in late summer or early autumn.Reports on low DO conditions in the Chesapeake Bay date back over a century[1].Consistent annual records of summer hypoxic conditions have been available since 1985 based on routine data collected through the Chesapeake Bay long-term water quality monitoring program[2].In 2023,the Chesapeake Bay Program(CBP)reported a record low seasonal hypoxic volume(May to October)of 0.58 cubic miles,accord-ing to the Maryland Department of Natural Resources,and 0.52 cubic miles,as reported by the Virginia Institute of Marine Science.Both volumes are considerably below the long-term average of 0.97 cubic miles(Fig.1).
