Weather map motion. Two-dimensional streamlines based on wind speeds at various levels show areas of convergence and divergence in the wind field, which are helpful in determining the location of features within the wind pattern. A popular type of surface weather map is the surface weather analysis, which plots isobars to depict areas of high pressure and low pressure. Cloud codes are translated into symbols and plotted on these maps along with other meteorological data that are included in synoptic reports sent by professionally trained observers. The use of weather charts in a modern sense began in the middle portion of the
Dirichlet boundary condition and are given numbers. For a partial differential equation, for example, where denotes the Laplace operator, the Dirichlet boundary conditions on a domain take the form where is a known function defined on the boundary . For example, the following would be considered Dirichlet boundary conditions: Many other boundary conditions are possible, including the Cauchy boundary condition and the mixed boundary condition. The latter is a combination of the Dirichlet and Neumann conditions. Dirichlet boundary condition In mathematics, the Dirichlet (or first-type) boundary condition is a type of boundary condition, named after Peter Gustav Lejeune Dirichlet (1805–1859). When imposed on