Mesoscale organisation of tropical convection

Moist convection is ubiquitous over tropical ocean, and it is associated with a spectrum of clouds ranging from small cumulus to congestus to deep convective clouds. These clouds can appear in isolation of in groups, forming clumps and an infinite diversity of horizontal patterns on a wide range of scales. At the mesoscale (20-200 km), the spatial arrangement of clouds results from some communication processes among clouds and between clouds and their environment; for this reason it is referred to as an organisation. While the beauty and fascinating diversity of convective organisations have been known for decades, it is only in the last decade that the mesoscale organisation of convection has begun to be appreciated as a fundamental feature of the atmosphere of great importance for climate.

Recent research has shown that the spatial organisation of convection (and hence clouds) at the mesoscale dramatically affects the Earth’s energy balance and hydrological cycle. This raises the question as to how the organisation of convection will change with warming, and how it will influence the climate.

Cumulus organisation photographed from the ISS (NASA, ISS066-E-37532)

The ERC1 funded MAESTRO project aims to answer this question by addressing the following goals:

  • Unravel the physical processes that control the mesoscale organisation of shallow and deep convection over tropical ocean
  • Understand how the organisation of convection impacts the Earth’s radiation budget through water vapor and clouds
  • Assess the ability of the new emerging climate models to predict the interplay between the mesoscale organisation of convection and climate

As part of this project, an airborne field campaign will be organized to collect the observations needed to test mechanisms hypothesized to control the mesoscale organisation of shallow and deep convection, and to assess the quality of the new EarthCARE satellite observations. This campaign will be one component of the international initiative named ORCESTRA.

  1. The MAESTRO project is funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Advanced Grant agreement No 101098063) ↩︎