Models for Initial Implementation

First uploaded on 2024/06/28
Copyright(C)2026 jos <jos@kaleidoscheme.com> All rights reserved.

Here, we explain which models should be used when first implementing the RDC scheme. Although many researchers may prefer to use the practical/operational models with which they are familiar, doing so will not allow for the correct implementation of the RDC scheme. As described below, an appropriate model must be configured for each stage.

For the initial implementation, the ideal atmospheric or fluid model is a reliable, non-hydrostatic, cumulus-resolving model that can explicitly handle buoyancy and vertical flow. Using this type of model optimizes the implementation process, ensuring that the results obtained during RDC scheme implementation match those obtained when cumulus effect is explicitly calculated without the scheme.

Of course, while a hydrostatic model is acceptable as the final target model, using it during the initial implementation stage is disadvantageous because it prevents verification of the RDC scheme's accuracy.

An Appropriate Model for Each Stage of the RDC Implemention

1. First, by simplifying a reliable 3D non-hydrostatic atmosphere or fluid model [A] and strictly controlling the energy balance, configure a radiative-convective model [B].


2. Use this radiative-convective model [B] to obtain the radiative-convective equilibrium state by integrating it over a long time period.


3. Implement the RDC scheme into the radiative-convective model [B] within the obtained radiative-convective equilibrium.
   This implementation process is actually a 3D RDC analysis within the model [B].
   In our original studies, we performed this analysis using 2D model atmospheres.


4. The following aspects cannot currently be determined solely from the RDC scheme theory:
   • the time interval Δt_R for RDC calculations
   • contrast for horizontal surface segmentation with respect to the radiative cooling rate distribution.
   These aspects of the RDC scheme implementation must be determined by comparing the results with and without the RDC scheme implementation within the model [B].


5. Port the RDC scheme implementation obtained through 3. and 4. into the target practical/operational model [C].
   The target model [C] does not need to be non-hydrostatic. Rather, it is particularly effective for models that have previously incorporated the effects of cumulus clouds through cumulus parameterization. The cumulus parameterization existing in the target model [C] can be replaced with the newly established RDC scheme implementation.
   Please note that the RDC scheme implementation optimized in the radiative-convective model [B] will be able to be integrated into the target model [C] seamlessly without requiring major modifications, as long as the physical processes do not differ significantly between the models [A], [B], and [C].

[NOTE]
You can easily verify beforehands the presence of RDC in any of the models by following How to Easily Verify the Presence of RDC in Your Atmospheric Model, based on the model’s time-averaged output values. However, please note that, if the target model [C] is hydrostatic and uses a Dynamical Detrainment parameterization that does not strictly account for the thermodynamic balance outside the cumulus domain, the expected relationship may be compromised.