Sensitivity of the Horizontal Scale of Convective Self‐Aggregation to Sea Surface Temperature in Radiative Convective Equilibrium Experiments Using a Global Nonhydrostatic Model

Abstract

In the tropics, convective activity organizes at a range of spatial scales. This organization is affected by external forcing such as land-sea contrast, sea surface temperature (SST) gradients, and synoptic equatorial waves. The organization of convective activities has been intensively studied using an idealized framework of radiative-convective equilibrium (RCE) experiments (Wing et al., 2017). In these simulations, convective activity spontaneously organized into a single cell, even though there was no inhomogeneous external forcing or rotation. In earlier works involving two-dimensional x-z plane RCE experiments, convective activity was generally concentrated at one location with a wavenumber-one structure (

The Impact of a Land‐Sea Contrast on Convective Aggregation in Radiative‐Convective Equilibrium

“…In the largest island simulations, when there is very little convection outside of the island area, this leads to a maximum cluster size of $$\mathcal{O}(10,000km)$$, approximately the diameter of the 50° island. Matsugishi and Satoh (2022) investigated the natural length scale of convective aggregation in global models, and at an SST of 305K they estimated this to be approximately 2,000 km. Yang (2018b) also found that a typical length‐scale of self‐aggregation is $$\mathcal{O}(2000km)$$.…”

Characteristic Form and Distance in High‐Level Hierarchical Structure of Self‐Aggregated Clouds in Radiative‐Convective Equilibrium

“…Matsugishi and Satoh (2022) conducted global RCE experiments and showed that the planetary radius must not be smaller than half of Earth's radius for the convergence of domain‐mean statistics and the representation of multiple aggregated clusters. Their results are consistent with those of PR19 and our results using regional models.…”

“…Identifying how energy transformation depends on the horizontal scale of the organization will deepen our understanding of the physical basis of moist convective organization. Matsugishi and Satoh (2022) conducted global RCE experiments and showed that the planetary radius must not be smaller than half of Earth's radius for the convergence of domain-mean statistics and the representation of multiple aggregated clusters. Their results are consistent with those of PR19 and our results using regional models.…”

Convection Self‐Aggregation in CNRM‐CM6‐1: Equilibrium and Transition Sensitivity to Surface Temperature

“…GCMs are run over about 3 years while CPM simulations only last 100 days. The latter may be enough for small‐domain CPMs to achieve equilibrium (e.g., Matsugishi & Satoh, 2022; Patrizio & Randall, 2019; Silvers et al., 2016), but this remains to be investigated for the largest CPM domains (Patrizio & Randall, 2019). In particular, such long self‐aggregation timescales may explain some of the strong differences between GCM and CPM RCE states and their sensitivity to SSTs.…”