DPAH Testbed: A Simple 1D Radiative-Convective Equilibrium Model with Dew-Point Anchor Hypothesis (Python Implementation)

Abstract

One-dimensional radiative-convective equilibrium (RCE) models have played a foundational role in modern climate science since the pioneering work of Manabe and Strickler (1964), who introduced convective adjustment to achieve realistic tropospheric lapse rates, and the influential study by Hansen et al. (1981), which highlighted the importance of water vapor feedback and cloud processes in determining climate sensitivity. Building upon this historic lineage, the DPAH Testbed introduces the Dew-Point Anchor Hypothesis (DPAH) as a physically grounded alternative for tropospheric anchoring.

Rather than relying primarily on fixed relative humidity or a prescribed critical lapse rate, the DPAH framework anchors the tropospheric temperature profile through explicit calculation of the Lifting Condensation Level (LCL) based on surface dew-point conditions. This produces a moist adiabat that is tightly coupled to surface thermodynamics. The model incorporates dynamic tropopause detection, stratospheric ozone heating, water vapor feedback via temperature-dependent relative humidity scaling, and tunable cloud feedback through longwave emissivity. Dual-mode simulations allow direct comparison between the Tropical Hadley Cell (~100 hPa tropopause) and the Polar/Ferrel Cell (~250 hPa tropopause).

Version 2.0 features improved numerical stability at the tropopause transition and diagnostic dashboards for sensitivity analysis. The DPAH Testbed serves as a transparent, exploratory platform for investigating moist convective anchoring and cloud feedbacks within the broader historical context of 1D RCE modelling.