The Indian Ocean Dipole (IOD) : Recent Studies

1) Which of the following statements is/are correct in context of 'Indian Ocean Dipole'?

a) It is a system of oscillating sea surface temperatures.
b) It influences the monsoonal rainfall in temperate regions of the world.
c) Both a and b
d) Neither a nor b

2) Consider the following statements regarding 'Positive Indian Ocean Dipole' :

i) It occurs when the sea surface temperatures are greater than normal in the Arabian Sea.
ii) It occurs when the sea surface temperatures are less than normal in the tropical eastern Indian ocean.
iii) It leads to greater monsoon rainfall.

Which of the following statements is/are correct?

a) i and iii only
b) i and ii only
c) iii only
d) All of the above

3) Which of the following statements is/are incorrect with respect to effects of El-nino and IOD on Indian summer monsoon rainfall?

a) The effect of El-nino is to increase the monsoon rainfall.
b) The effect of negative IOD is to decrease the monsoon activity over India.
c) Both a and b
d) Neither a nor b

4) Recent studies indicate that 'early IOD' which peaks in the mid-monsoon months plays a significant role in enhancing monsoon rainfall. Which of the following geographical events leads to such an enhanced effect?

a) Arabian sea evaporation.
b) Strong cross equatorial flow.
c) Both a and b
d) Neither a nor b

Answers:

1) a , IOD influences the Indian summer monsoon rainfall which lies in tropical and sub tropical area.
2) d
3) a
4) c

Reference : The Hindu