UPSC CSE Prelims 2020
Statement 2 is correct. Ocean Mean Temperature (OMT) collected during the January-March period is a significant indicator for forecasting the performance of the subsequent Indian Summer Monsoon (June-September). Research indicates that OMT, which represents the thermal energy stored in the upper ocean, provides a more reliable assessment of monsoon rainfall anomalies (whether it will be less or more than the long-term mean) compared to Sea Surface Temperature (SST) alone. This is because OMT accounts for the heat content of a deeper layer of the ocean, which influences atmospheric circulation patterns more persistently.
Statement 1 is incorrect. While OMT is indeed measured up to the depth of the 26°C isotherm, the specified depth of 129 meters for the south-western Indian Ocean during January-March is inaccurate. Studies and observations suggest that the average depth of the 26°C isotherm in this region during the January-March period is considerably shallower, typically around 59 meters, not 129 meters.
Option (a) is incorrect because Statement 1 is factually inaccurate regarding the depth of the 26°C isotherm.
Option (c) is incorrect because Statement 1 is false.
Option (d) is incorrect because Statement 2 is correct.