On atmospheric pressure and temperature correlation across various terrain types

Temperature (T), pressure (p), and density ($\rho$) are fundamental variables describing the atmospheric behavior. This study investigates the interdependence of these variables near Earth's surface in real-world conditions, by evaluating data from different European weather stations. It has been found that the correlation between pressure and temperature is strongly related to the dynamics of the PBL that facilitates a two-group classification. The first group includes all the stations in the plain or in the valley-floor and exhibits a weak correlation, R(p,T). 2D density plots representing hourly pressure against temperature have a distinctive triangular shape at these stations. Regardless of location, the upper boundary of this triangle consistently fits a linear equation with a constant slope and an intercept that scales with the average pressure of the station. This finding holds promising implications for enhancing the quality check of pressure and temperature data, enabling the identification of implausible measurements using a unified equation. In contrast, the second group includes stations with a strongly positive correlation R(p,T) and a more linear density plot; it includes all stations near a mountain-top. Their correlations exhibit identical features when compared to radiosounding data extracted at corresponding heights. The study concludes that: i) the first group of stations is significantly influenced by non-hydrostatic processes such as turbulence, friction and surface radiative heating/cooling in the PBL, resulting in weakly negative R(p,T) for shorter timescales that become null over longer durations; ii) the second group of stations has R(p,T) characteristics similar to the free atmosphere, predominantly regulated by hydrostatic balance and the advection of sensible heat.