With reference to Ocean Mean Temperature (OMT), which of the following statements
is/are correct?
1. OMT is measured up to a depth of 26°C isotherm which is 129 meters in the southwestern Indian Ocean during January – March.
2. OMT collected during January – March can be used in assessing whether the
amount of rainfall in monsoon will be less or more than a certain long-term mean.
Select the correct answer using the code given below:
Explanation
Sea surface temperature (SST) is routinely used for predicting whether the total amount
of rainfall that India receives during the monsoon season will be less or more than the
long-term mean of 887.5 mm.
• OMT is analysed by measuring the ocean thermal energy during the period from January
to March. Using OMT data, scientists are able to predict with 80% probability the
monsoon of any year. Hence, statement 2 is correct.
• SST is restricted to a few millimetres of the top ocean layer, whereas OMT which is
measured up to a depth of 26 degree C isotherm, is more stable and consistent, and the
spatial spread is also less. The 26 degree C isotherm is seen at depths varying from 50–
100 metres. During January–March, the mean 26 degree C isotherm depth in the
Southwestern Indian Ocean is 59 metres. Hence, statement 1 is not correct.
Therefore, the correct answer is (b).