TopographyTopography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary science and is concerned with local detail in general, including not only relief, but also natural, artificial, and cultural features such as roads, land boundaries, and buildings.
Cauchy momentum equationThe Cauchy momentum equation is a vector partial differential equation put forth by Cauchy that describes the non-relativistic momentum transport in any continuum. In convective (or Lagrangian) form the Cauchy momentum equation is written as: where is the flow velocity vector field, which depends on time and space, (unit: ) is time, (unit: ) is the material derivative of , equal to , (unit: ) is the density at a given point of the continuum (for which the continuity equation holds), (unit: ) is the stress tensor, (unit: ) is a vector containing all of the accelerations caused by body forces (sometimes simply gravitational acceleration), (unit: ) is the divergence of stress tensor.
Air pollution forecastingAir pollution forecasting is the application of science and technology to predict the composition of the air pollution in the atmosphere for a given location and time. An algorithm prediction of the pollutant concentrations can be translated into air quality index, same as actual measurements. Countries and cities are given forecasts by state and local government organizations, as well as private companies like Airly, AirVisual, Aerostate, Ambee, BreezoMeter, PlumeLabs, and DRAXIS that provide air pollution forecasts.
Grade (slope)The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which run is the horizontal distance (not the distance along the slope) and rise is the vertical distance.
Atmospheric tideAtmospheric tides are global-scale periodic oscillations of the atmosphere. In many ways they are analogous to ocean tides. Atmospheric tides can be excited by: The regular day–night cycle in the Sun's heating of the atmosphere (insolation) The gravitational field pull of the Moon Non-linear interactions between tides and planetary waves. Large-scale latent heat release due to deep convection in the tropics.
