Topic: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.
2) What do you understand by Pacific decadal oscillation? discuss in detail the causative factors and effects.(250 words)
Why this question:
The article captures the context of Northeast India, one of the wettest places on the Earth that has been experiencing rapid drying, especially in the last 30 years. It highlights that the decreasing monsoon rainfall is associated with natural changes in the Pacific decadal oscillation (PDO).
Key demand of the question:
The answer must discuss the concept of PDO in detail.
Discuss – This is an all-encompassing directive – you have to debate on paper by going through the details of the issues concerned by examining each one of them. You have to give reasons for both for and against arguments.
Structure of the answer:
Explain what is PDO?
Body of the answer should discuss the following:
- What is PDO? – It is a long-lived El Niño-like pattern of Pacific climate variability. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20°N.
- Major changes in northeast Pacific marine ecosystems have been correlated with phase changes in the PDO; warm eras have seen enhanced coastal ocean biological productivity in Alaska and inhibited productivity off the west coast of the contiguous United States, while cold PDO eras have seen the opposite north-south pattern of marine ecosystem productivity.
- How is it different from ENSO?
- Causative factors? Consequences of such a geophysical phenomenon?
Conclude with influence of such a phenomenon.