Foehn wind there is no precipitation, implies there must be other mechanisms. 2) Isentropic draw-down (the draw-down of warmer, drier air from aloft): When the approaching winds are insufficiently strong to propel the low-level air up and over the mountain barrier, the airflow is said to be 'blocked' by the mountain and only air higher up near mountain-top level is able to pass over and down the lee slopes as foehn winds. These higher source regions provide foehn air that becomes warmer and drier on the leeside after it is compressed with descent due to the increase in pressure towards the surface.
Dirichlet boundary condition 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 an ordinary or a partial differential equation, it specifies the values that a solution needs to take on along the boundary of the domain. The question of finding solutions to such equations is known as the Dirichlet problem. In applied sciences, a Dirichlet boundary condition may also be referred to as a fixed boundary condition. For an ordinary differential equation, for instance, the Dirichlet boundary conditions on the interval take the form where