Negative Arctic Oscillation influences winter in India
Q. Which of the following is/are true about Arctic Oscillation?
1) Negative Arctic Oscillation leads to warmer winter in India
2) The Arctic Oscillation influences winter weather in the Northern Hemisphere only.- Published on 27 Jan 16a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2
ANSWER: Only 2
The Arctic Oscillation influences winter weather in the Northern Hemisphere; when it is negative, arctic air slides south. It brings a blast of cold Siberian winds to the Indian region. The degree to which Arctic air penetrates into middle latitudes is related to the AO index, which is defined by surface atmospheric pressure patterns.
When the Arctic oscillation (AO) index is positive, surface pressure is low in the polar region. This helps the middle latitude jet stream to blow strongly and consistently from west to east, thus keeping cold Arctic air locked in the polar region. When the AO index is negative, there tends to be high pressure in the polar region, weaker zonal winds, and greater movement of frigid polar air into middle latitudes.
