Context:
As climate change drives up, glaciers around the world’s tallest mountains are actually getting slightly colder during the warm season, according to new research published in the peer-reviewed journal Nature Geoscience.
Highlights of the study:
- Maximum daytime temperature during the warmer months decreased by around 0.040 °C per year over the last 15 years.
- Cooling trend wasn’t just limited to the glaciers around Mt. Everest, it was across the entire Himalayas.
- The cooling trend is the result of a well-understood phenomenon called katabatic winds.
Katabatic Wind:
- Katabatic wind – The cool air from mountains draining into the valley
- Occurs during – Night
- Belongs to – Seasonal or Secondary Wind
- Impact – Slow down the effects of the global climate crisis in lower altitude region
Anabatic Wind:
- Anabatic Wind – The warm, less dense air rises up the valley sides
- Occurs during – Day time
- Impact – Helps in melting the snow in high altitude region
Geostrophic wind:
- Geostrophic wind – Wind blowing parallel to the isobars or perpendicular to Pressure Gradient Force
- Reason – When isobars are straight and there is no friction, pressure gradient force is balanced by the Coriolis force and the resultant wind blows parallel to the isobar.
- Features-
- Subjected to greater Coriolis force
- Flow at great speeds due to low friction
- Deflect greatly giving rise to 3 distinct cells called Hadley cell, Ferrel Cell and Polar cell
- Example – Jet Stream (geostrophic wind blowing horizontally through the upper layers of the troposphere)
Source: Business Insider
Previous Year Question
Westerlies in the southern hemisphere are stronger and persistent than in the northern hemisphere. Why?
1. The Southern Hemisphere has less landmass as compared to the Northern Hemisphere.
2. Coriolis force is higher in the Southern Hemisphere as compared to the Northern Hemisphere.
[UPSC Civil Service Exam – 2011 Prelims]
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (a)
Explanation: Statement 2 is incorrect. Coriolis force is strongest in the polar regions and zeroes at the equator.
