Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc., geographical features and their location- changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
Atlantic Meridional Overturning Circulation (AMOC)
What to study?
For Prelims: What is AMOC?
For Mains: How warming up of Indian Ocean affects AMOC?
Context: Since the past 15 years, Atlantic meridional overturning circulation (AMOC) has been weakening — a development that could have dramatic consequences for Europe and other parts of the Atlantic rim. Warming up of Indian Ocean is said to be a key driver behind this.
How it affects?
Warming in the Indian Ocean generates additional precipitation, which, in turn, draws more air from other parts of the world, including the Atlantic.
The higher level of precipitation in the Indian Ocean will reduce precipitation in the Atlantic and increase salinity in the waters.
What is the Atlantic Meridional Overturning Circulation?
The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic.
It aids in distributing heat and energy around the earth, as the warm water it carries releases heat into the atmosphere, and in absorbing and storing atmospheric carbon.
How does the AMOC work?
- The AMOC is a large system of ocean currents, like a conveyor belt, driven by differences in temperature and salt content – the water’s density.
- As warm water flows northwards it cools and some evaporation occurs, which increases the amount of salt. Low temperature and a high salt content make the water denser, and this dense water sinks deep into the ocean.
- The cold, dense water slowly spreads southwards, several kilometres below the surface. Eventually, it gets pulled back to the surface and warms in a process called “upwelling” and the circulation is complete.
Sources: Down to earth.