Kathmandu vs Bangalore: Climate Similarities and Differences

 



More than a thousand miles stretch between Kathmandu and Bangalore, two cities in South Asia.  But because Kathmandu is located to the south of the Himalayas, these two locations are able to share the same weather patterns.  There is a net elevation gain from Bangalore to Kathmandu as the landscape gently climbs into the foothills of the Himalayas.

This GoogleEarth image shows the spatial relationshp between Kathmandu and Bangalore.  These cities are 1,135 miles apart.  There is a net elevation loss of 1,277 feet between Kathmandu and Bangalore's city centers, although the terrain spikes sharply about 17 miles southwest of Kathmandu to almost 7,000 feet.  Kathmandu sits in a lowland region, surrounded by higher elevations to the north and south. Bangalore sits atop a plateau.

The intertropical convergence zone plays a crucial role in south Asia's climate.  In the ITCZ, warm, moist air is picked up near the equator and re-deposited elsewhere.  Both of these cities are subject to the whims of the ITCZ.  During the winter months, the ITCZ is located far south of the Indian region, as depicted in the graphic below.  As a result, Bangalore and Kathmandu are not subject to the warm, moist air currents of the ITCZ.  Instead, colder continental air flows from Asia in the direction of the Indian Ocean, resulting in dry, temperate winters.

http://milliethegeographer.blogspot.com/2012/03/atmosphere-and-circulation-help.html

This satellite image shows the ITCZ in January
(the thick band of clouds near the equator). 
The ITCZ is well south of both locations during the wintertime.

Bangalore is located in the semi-arid region of India.
 It receives little precipitation during the winter months.
 http://cee45q.stanford.edu/2003/briefing_book/india.html

Tables courtesy of climate-zone.com

 

A side-by-side comparison of the weather patterns of Kathmandu and Bangalore illustrates the fact that these two cities are subject to the same weather patterns.  Bangalore is lower in elevation and lower in latitude, which leads to slightly higher average temperatures during the summer months and much higher average temperatures during the winter months.  Bangalore maintains these warmer temperatures during the winter months because relative humidity is consistently higher than it is in Kathmandu.  Also worthy of note are the similarities in these areas' monsoon patterns.  Both locations' rainy seasons begin to ramp up during April and peak during the months of July and August before tapering off in September.

Widespread flooding often occurs in Nepal and India as a result of excessive summer rain and Himalayan snowmelt.  http://www.time.com/time/photogallery/0,29307,1650392_1422870,00.html

Air Masses in Nepal

Wind!



http://www.kuoni.co.uk/en/holiday/asia/nepal/pages/default.aspx



http://www.phoolbari.com/tourism/aboutnepal.html















Kathmandu serves as a popular destination
 for mountaineers before they ascend into the high Himalayas!


In the northern hemisphere, latitudes between thirty and zero degrees are normally subject to the northeast trades that move from subtropical high pressure to equatorial low pressure.  However, Nepal is a special exception.  The Himalayas act as a great barrier against the cold air that sweeps across Asia.  Arcing gently east-west across the region, the mountains shield Kathmandu from these air masses (cP and cA), resulting in the city's surprisingly temperate climate.  Kathmandu's climate comes as a shock to some because it seems to defy that which the region is known for: high altitude adventure. 



The temperatures of the city itself are quite moderate. 
Here, Kathmandu's cricket team enjoys a spring day



This satellite image shows how the Himalayas protect south Asia from cold, NE air masses.  Clouds are clustered near the top of the image, but cease abruptly near the base of the mountain range. 



Nepal is affected primarily by maritime tropical wind currents from the Indian Ocean and is also subject to an annual summer monsoon.  Air masses sweep to the northwest over the Indian Ocean where they become warm and moist before circling towards India, generating precipitation during the months of June-August.

This map illustrates the precipitation and wind patterns experienced during south Asia's summer monsoon season.  Kathmandu is located just below the dashed line at 27°42′N 85°20′E.  It's no coincidence that air masses suddenly change direction when they come to the dashed line--the line follows the arc of the Himalayas.
http://www.theresilientearth.com/?q=content/monsoons-megadroughts

Kathmandu is not affected by mid-latitude cyclones, as illustrated below.

This image shows the typical paths of mid-latitude cyclones (black arrows) and hurricane tracks (green).  Kathmandu is a  mid-latitude cyclone will not develop over this region because the Himalayas prevent tropical air masses from merging with the polar air masses that dominate Asia.
http://www.physicalgeography.net/fundamentals/7s.html