Why Has The Ocean Been So Cold Lately?

Have you noticed how cold the ocean has been on LBI the past few weeks? With unrelenting south wind, ceaseless fog, and numbing brown water, I did a little research on why this occurs.

When a south wind blows along the coast of New Jersey, it sets in motion a series of oceanographic processes involving the Coriolis effect and Ekman transport that result in the upwelling of cold water.

In the Northern Hemisphere, the Coriolis effect causes moving water to veer to the right of the wind direction. As the south wind pushes surface water along the coast, this water is deflected westward, away from the shore. This movement of water is further influenced by Ekman transport, which describes how the wind-driven surface water creates a spiral effect through the water column. Each layer of water, deflected progressively to the right, results in the net movement of water at a 90-degree angle to the right of the wind direction.

Consequently, the south wind leads to a westward displacement of surface water away from the New Jersey coastline. To compensate for this displaced water, deeper, colder, and nutrient-rich water rises from below to the surface, a process known as upwelling. This upwelled water replaces the surface water moved offshore, bringing colder temperatures to the coastal waters of New Jersey. The island saw ocean temperatures fall to the low 50’s, even reading 49° one chilly morning.

Therefore, the combination of the Coriolis effect and Ekman transport due to the south wind results in the upwelling of cold water along the New Jersey coast.

The ocean is a complex and ever-shifting environment. Gaining the proper knowledge of important processes like something seemingly as simple as upwelling can provide the proper insight to be prepared! As we continue through July, I am ever hopeful for a North or East wind to help bring back the warm water sitting right off the coast. Stay warm and be mindful of the South wind!