Oceanography Flashcards
(41 cards)
What are Isotherms?
Lines joining places having equal temperature.
How do isotherms generally align with latitude?
They are generally parallel to the latitude.
When and where are deviations of isotherms from latitude most pronounced?
In January, especially in the Northern Hemisphere.
How do isotherms deviate in January over oceans and continents in the Northern Hemisphere?
They deviate to the north over the ocean and to the south over the continent.
What causes isotherms to bend northwards over the North Atlantic in January?
The presence of warm ocean currents like the Gulf Stream and North Atlantic drift.
How does the variation in temperature in the Southern Hemisphere compare to the Northern Hemisphere?
Variation is more gradual, and isotherms are more parallel to latitudes due to the pronounced effect of the ocean.
What is Ocean Mean Temperature (OMT) measured up to?
The depth of the 26 degree C isotherm.
What is the typical depth range for the 26 degree C isotherm?
50-100 metres.
Which is generally more stable and consistent: Sea Surface Temperature (SST) or Ocean Mean Temperature (OMT)?
OMT.
Which has shown a better success rate in predicting the Indian summer monsoon: SST or OMT?
OMT (80% success rate) compared to SST (60% success rate).
What temperature range do most corals require?
Between 23° and 29° Celsius.
In which water types are corals primarily confined due to their narrow temperature range?
Tropical and semi-tropical waters.
Which three countries contain over one-third of the world’s coral reefs?
Australia, Indonesia, and the Philippines.
How does the biodiversity of coral reefs compare to tropical rainforests?
Coral reefs are believed to have higher biodiversity, hosting more animal phyla despite occupying less than 1% of the ocean floor.
What is the primary cause of high and low tides?
The Moon’s gravitational pull generating the tidal force.
How does the tidal force cause high tides?
It causes Earth’s water to bulge out on the side closest to the moon and the side farthest from the moon.
What unique phenomenon occurs at Chandipur beach during low tides?
The beach recedes up to 5 km, allowing people to walk on the sea bed.
What is the Indian Ocean Dipole (IOD) defined by?
The difference in sea surface temperature between the western pole (Arabian Sea) and the eastern pole (eastern Indian Ocean south of Indonesia).
How can an IOD phenomenon influence El Niño’s impact on the monsoon?
A positive IOD can amplify El Niño impacts, while a negative IOD can diminish them, especially concerning rainfall variability in regions surrounding the Indian Ocean Basin.
In which direction does the Equatorial Counter Current flow?
Eastward.
Why do tropical cyclones generally not originate in the South Atlantic and South-Eastern Pacific regions?
The Inter Tropical Convergence Zone (ITCZ) seldom occurs there, and the Coriolis force is too weak.
What basic condition is required for tropical cyclone formation?
Warm ocean waters near the equator.
