Tracer Advection Using Dynamic Grid Adaptation and MM5
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.
History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.
Dates of Existence
1902–present
Historical Names
- Department of Farm Crops and Soils (1917–1935)
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- College of Agriculture and Life Sciences (parent college)
The Department of Geological and Atmospheric Sciences offers majors in three areas: Geology (traditional, environmental, or hydrogeology, for work as a surveyor or in mineral exploration), Meteorology (studies in global atmosphere, weather technology, and modeling for work as a meteorologist), and Earth Sciences (interdisciplinary mixture of geology, meteorology, and other natural sciences, with option of teacher-licensure).
History
The Department of Geology and Mining was founded in 1898. In 1902 its name changed to the Department of Geology. In 1965 its name changed to the Department of Earth Science. In 1977 its name changed to the Department of Earth Sciences. In 1989 its name changed to the Department of Geological and Atmospheric Sciences.
Dates of Existence
1898-present
Historical Names
- Department of Geology and Mining (1898-1902)
- Department of Geology (1902-1965)
- Department of Earth Science (1965-1977)
- Department of Earth Sciences (1977-1989)
Related Units
- College of Liberal Arts and Sciences (parent college)
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Abstract
A dynamic grid adaptation (DGA) technique is used to numerically simulate tracer transport at meso- and regional scales. A gridpoint redistribution scheme is designed to maximize heuristic characteristics of a “good” grid. The advective solver used in conjunction with the DGA is the multidimensional positive definite advection transport algorithm (MPDATA). The DGA results for regional tracer transport are compared against results generated using the leapfrog as well as MPDATA advection schemes with uniformly spaced, static grids. Wind fields for all tracer transport algorithms are provided by the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). A mesoscale-sized test case with idealized initial condition and wind field clearly shows qualitatively and quantitatively the advantage of using the dynamic adaptive grid, which is a marked reduction in numerical error. These results are further corroborated by more realistic test cases that used NCEP–NCAR reanalysis data from 6–11 March 1992 to set initial and boundary conditions for (i) a mesoscale-sized, 24-h simulation with an idealized initial tracer field, and (ii) a regional, 5-day simulation with water vapor field initialized from the reanalysis data but then treated as a passive tracer. A result of interest is that MPDATA substantially outperforms the leapfrog method with fourth-order artificial dissipation (central to MM5) in all of our test cases. We conclude that with dynamic grid adaptation, results with approximately the same accuracy as a uniform grid may be obtained using only a quarter of the grid points of the uniform grid MPDATA simulations. Compared to results generated using the leapfrog method on a uniform grid, the DGA does even better.
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This article is from Mon. Wea. Rev., 133, 175–187. doi: http://dx.doi.org/10.1175/MWR-2850.1. Posted with permission.