With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean. 2. An IOD phenomenon can influence an El Nino's impact on the monsoon. Select the correct answer using the code given below:

The correct answer is B, 2 only. Statement 1 is wrong because the IOD is the difference in sea surface temperature between the tropical western Indian Ocean (off East Africa) and the tropical eastern Indian Ocean (near Sumatra and Java). The Eastern Pacific is the arena of El Nino and La Nina, not the IOD. Statement 2 is correct: a positive IOD, with a cooler east and warmer west, can partly offset the drying effect of an El Nino on the Indian monsoon, while a negative IOD can add to it.

• Statement 1: wrong ocean pair, since the second pole is the eastern Indian Ocean, not the Eastern Pacific.
• Statement 2: correct, because the two Indo-Pacific climate modes interact and modify each other's monsoon impact.

Core concept: the Indian Ocean Dipole as a coupled ocean-atmosphere mode, distinct from ENSO, and their combined influence on monsoon rainfall. This links to the monsoon and climate chapters of Geography and to Mains GS-1 questions on monsoon variability and forecasting.

Trap: Aspirants see the words dipole and Pacific alongside El Nino and assume the Pacific pair is correct. The IOD is an Indian Ocean phenomenon, so check the names of the two poles.