Painopinta

Painopinta (plural painopinnat) is a meteorological term used in Finnish to denote a surface of constant atmospheric pressure, an isobaric surface in English. The surface is defined by p = constant, with p measured in hectopascals (hPa).

Painopinnat are used to visualize and analyze the vertical structure of the atmosphere. Because pressure decreases with height, each painopinta traces a curved 3D surface that intersects different altitudes depending on location and weather. They are commonly used with radiosonde data, upper-air analyses, and numerical weather prediction to study how weather systems extend through the troposphere and beyond.

Common reference surfaces include the 1000 hPa surface near sea level, the 850 hPa surface around 1.5 km, the 500 hPa surface around mid-troposphere (about 5.5 km), and the 300 hPa surface in the upper troposphere. Differences in temperature shift the altitude of these surfaces at a given location.

Painopinta differs from isobars drawn on a standard weather map, which are lines of equal surface pressure at a fixed reference altitude (usually sea level). In models and analyses that use pressure coordinates, the vertical dimension is represented by pressure rather than height, making painopinnat a convenient framework for understanding atmospheric dynamics.