Characterizing Convection Schemes Using Their Responses to Imposed Tendency Perturbations

Convection is usually parameterized in global climate models, and there are often large discrepancies between results obtained with different convection schemes. Conventional methods of comparing schemes using observational cases or directly three-dimensional (3D) models do not always clearly identify parameterization strengths weaknesses. In this paper we evaluate the response parameterizations to various perturbations rather than their behavior under particular strong forcing. We use linear function method proposed by Kuang (2010) compare 12 physical packages five atmospheric single-column model (SCM) simulations idealized radiative-convective equilibrium conditions. The forced anomalous temperature moisture tendencies. departures from compared published a cloud-resolving (CRM). Results show that procedure capable isolating scheme other physics areas agreement but also substantial differences schemes, some which can be related design. Some aspects responses RCE profiles (the relative humidity profile particular), while others constitute independent diagnostics. All SCMs irregularities discontinuities likely threshold-related mechanisms used appear CRM. Our highlight potential flaws suggest possible new directions explore for evaluation.