Buoyancy storms in a zonal stream on the polar beta-plane: experiments with altimetry

TL;DR

This study investigates buoyancy-driven flows and beta-plumes in a polar beta-plane setting through laboratory experiments, revealing how background currents influence plume formation and transport velocities.

Contribution

It provides experimental insights into the interaction between localized heating, background zonal flows, and beta-plume dynamics on the polar beta-plane.

Findings

Westward transport velocity proportional to upwelling velocity

Background eastward flow can suppress beta-plume formation

Critical zonal flow velocity threshold for beta-plume existence

Abstract

Results from a new series of experiments on flows generated by localized heating in the presence of a background zonal current on the polar beta-plane are presented. The flow induced by a heater without the background zonal flow is in the form of a beta-plume. Zonal jets of alternating directions are formed within the plume. The westward transport velocity in the plume is proportional to the upwelling velocity above the heater in agreement with linear theory. When the background flow in the form of the eastward zonal current is present, the beta-plume can be overwhelmed by the eastward current. The main control parameters of the experiment are the strength of the heater and strength of the sink which is used to create the background flow. The regime diagram shows the area where a beta-plume can exist in the parameter space. The critical value of the velocity of the zonal flow below which the beta-plume can exist is obtained by considering barotropic Rossby waves emitted by the baroclinic eddies in the heated area.