Tides and Currents
Traveling to the Maritime Provinces of Canada in January can be a challenge with temperatures averaging well below 0o C. At the same latitude, temperatures in January in England average above 0o C. One might expect similar temperatures to occur at the same latitudes because of the influence of the Sun on heating Earth's surface. So why is England so warm compared to the Maritimes of Canada? An important influence is the ocean and its tides and currents. Tides in the Bay of Fundy, New Brunswick, Canada average 10-14 meters, and tides in Southern England average around 5 meters. At the same time New Brunswick is adjacent to the southward flowing Labrador current and England and Northern Europe the northward extension of the Gulf Stream current. Does the ocean have enough influence to impact the climate in these areas? And why would the impacts differ despite their similar positions?
Tides and currents occur naturally in the ocean and are influenced by many factors. Tides are caused by the gravitational attraction of the Sun and the Moon, and vary in different locations due to the influence of the shape of coastlines. In some locations, tides may change be only a few centimeters where in other places they may be over ten meters. Currents are caused by tides, winds at or near the ocean's surface, and thermohaline circulation. As Earth's climate, coastal areas, and land uses change, so too do currents. In this module, you will learn about the physics of tides and currents, the technology used to measure them and the applications for these measurements. These applications include the use of tides and currents for coastal management and marine commerce, such as the efficient and safe navigation of ships across the ocean and under bridges. Since tides and currents strongly affect everyday life, this module also includes resources for understanding how humans are affecting tides and currents directly through modifications of coastal land, including the development of beach front homes and resorts; construction of marine and terrestrial transportation infrastructure such as roads, bridges, and shipping channels; and increased erosion of sediment which is deposited in the ocean. By studying these events, you will begin to understand how tides and currents impact many aspects of our daily lives. Finally, this unit explores the effects of climate change on tides and currents and the effect tides and currents have on climate change.