EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation

Abstract

Trade-wind cumuli constitute the cloud type with the highest frequency of occurrence on Earth, and it has been shown that their sensitivity to changing environmental conditions will critically influence the magnitude and pace of future global warming. Research over the last decade has pointed out the importance of the interplay between clouds, convection and circulation in controling this sensitivity. 123Surv Geophys (2017) 38:1529-1568 https://doi.org/10.1007/s10712-017-9428-0 cumuli at cloud base is very sensitive to changes in environmental conditions, while process models suggest the opposite. To understand and resolve this contradiction, we propose to organize a field campaign aimed at quantifying the physical properties of tradecumuli (e.g., cloud fraction and water content) as a function of the large-scale environment. Beyond a better understanding of clouds-circulation coupling processes, the campaign will provide a reference data set that may be used as a benchmark for advancing the modelling and the satellite remote sensing of clouds and circulation. It will also be an opportunity for complementary investigations such as evaluating model convective parameterizations or studying the role of ocean mesoscale eddies in air-sea interactions and convective organization.

Sugar, gravel, fish and flowers: Mesoscale cloud patterns in the trade winds

“…A motivation for this activity was an appreciation of the important role the organisation of deep convection plays in regulating radiative heat‐loss to space (Tobin et al ., ), and hence an emerging curiosity as to whether similar processes were occurring in shallow convection. A further motivation was to help prepare for a forthcoming field programme (Bony et al ., ): if patterns of organisation exist for shallow convection, then their appearance might influence how one organises the measurement campaign. These general motivations gave rise to more specific questions.…”

A Survey of Precipitation-Induced Atmospheric Cold Pools over Oceans and Their Interactions with the Larger-Scale Environment

“…New observational capabilities and strategies were employed during the Rain in Cumulus over Ocean campaign (RICO; Rauber et al 2007) and Dynamics of the MJO campaign (DYNAMO; Yoneyama et al 2013) and will be during the upcoming Elucidating the role of clouds-circulation coupling in climate campaign (EUREC 4 A; Bony et al 2017). These advance early observational studies stymied by imprecise data collocation and measurement misunderstanding (e.g., Warner et al 1979;LeMone 1980) that had difficulty perceiving the larger-scale mesoscale organization.…”

Gravity Wave Influences On Mesoscale Divergence: An Observational Case Study

“…Clouds and their coupling to circulation still remain one of the major uncertainties in climate predictions (Bony et al, ). The temporal and spatial scales reported here can serve as guidance for measurements during future field campaigns, such as the field campaign Elucidating the Role of Cloud‐Circulation Coupling in Climate (EUREC4A Bony et al, ), which will take place in winter 2020, and could be used to collect additional data for analyzing the response of convection to GW dynamics in relation to other cloud controlling factors. The relatively short inertial periods of the waves (Table ) favor soundings at short intervals, ideally every 2 hr.…”