OVERVIEW
Ekman is an oceanographic and environmental consulting company
Created by oceanographers with wide experience on environmental analysis and field work. The main purpose of our company is to provide high quality environmental studies to Oil & Gas activities and coastal engineering projects.
Our team is composed of experts on several areas, allowing us to offer a large range of services. Our technicians perform environmental studies, meteorological and oceanographic data analysis, environmental diagnosis, pollutant dispersion modeling, operational oceanography, environmental monitoring and development of equipment and solutions.
Explaining the Brand
The name of our company was chosen as a tribute to one of the most important oceanographer to date: Vagn Walfrid Ekman.
Vagn Walfrid Ekman was born in Sweden in 1874, studied physics at Uppsala University and joined the International Laboratory for Oceanographic Research in Oslo after completing his doctorate.
Besides developing instruments such as the current meter and water bottle, Ekman published a fundamental study entitled “On the Influence of the Earth’s Rotation on Ocean Currents”.
This work originated from observations made by the explorer Fridtjof Nansen in the Arctic. He noticed that the drift ice did not follow the wind direction but deviated to the right.
Ekman’s research was the first of a remarkable series of studies conducted during the first half of the twentieth century that led to a better understanding of how winds drive the ocean’s circulation. Since its publication, Ekman’s theory has been used on several different applications. The results obtained by him are described below.
Ekman’s assumptions:
› constant winds;
› ocean with no boundaries;
› homogeneous flow;
› horizontal flow;
› steady flow.
Using those assumptions, Ekman obtained the simplest formulation to represent the currents generated by the winds: the balance between Coriolis Force and Friction Force.
Ekman Spiral
The Ekman Spiral is a simple scheme used to represent the results obtained by Ekman’s research. The Ekman Spiral indicates that surface water moves at an angle of 45 degrees related to the wind direction (it deflects to the right on Northern Hemisphere and to the left on Southern Hemisphere). The direction of the water movement changes with increasing depth due to Coriolis Effect. The net water movement is 90 degrees to the right of the wind direction on Northern Hemisphere, while on Southern Hemisphere the water movement is to the left. This net transport of water due to coupling between wind and surface waters is known as Ekman transport.
Upwelling
An interesting application of Ekman’s discoveries was the explanation of the upwelling phenomenon, when deep, cold and rich waters rises to the surface. This phenomenon is constant along the Brazilian coast (i.e. Cabo Frio and Cabo de São Tomé upwelling) especially in the summer when NE winds blow over long periods.
The NE winds generate an Ekman transport off the coast, causing deep water to rise to fill the gap left by the surface water. This explains the cold water observed on the coast of Rio de Janeiro in the summer.
[1] Thurman, Harold. Essentials of Oceanography, 5th ed., Prentice-Hall Inc., 1996.[2] Garrison, Tom. Oceanography: An Invitation to Marine Science, Wadsworth Publishing Company, Belmont, 1993, 540 pp.