Historical Climatology of Bangalore and the Growth of the City

As with all the locations of the world, an accurate description of a localities weather and climate regime must consider the various scales that influence it and make each individual location unique. In meteorology, scales are distinguished spatially as either micro, meso, or macro, from smallest to largest respectively, and the latter of which will be discussed in the next post.  So far, this blog has focused extensively and nearly exclusively on the meso (regional) scale of the Indian subcontinent and surrounding environments.  This includes discussion of Bangalore’s position in relation to the Indian Ocean and the Asian Continent, as well as the ITCZ and the Himalayan Mountains. Combined, these factors contribute to a generalized regional weather system, which is often portrayed on maps using classification systems such as Koppen-Geiger. However, each specific location has its own unique weather and thus climate.  These variations’s can be seen from city to city, city to rural, or wholly within the city itself, at the micro-scale.  In the case of Bangalore the most pronounced factor that is currently changing, as well as differentiating its climate from its neighbors, is the near exponential population growth and the subsequent expansion of the city proper. Known as an urban heat island effect, the city itself tends to be warmer than the surrounding environments. Also precipatation tends to be slighltly higher on the windward side of the city, a situation which would not have occured otherwise. The cause behind urban heat islands is belevied to be from an increase in the albedo of built environments, a decrease in evapotranspiration, and an increase in environmental air pollutants.

The above records are from the Indian government's Ministry of Home Affairs, the branch which is responsible for the decadal census of the country.  This type of growth is seen throughout the country  and India is expected to surpass China sometime in the next couple of decades as the most populous country in the world.  The city of Bangalore has several times been the fastest growing major city in the country and consistently been among the fastest growing cities in the world.

The above graph is the historical mean high and low temperatures for Bangalore along with the annual precipitation. Though high temperatures have remained relatively consistent, the mean low has increased significantly from 1901 to 2000. Also take note at the extreme variation in precipitation, from over 100 mm in one year to a half a decade straight of no recordable amount.

The historical records for July show an upward trend in both the mean highs and mean lows for the month and with an almost 1.5 degree Celsius increase in the average low over the century long period.  It should be noted that the reason for the lack of information of the most recent decade is the propriety stance of the Indian Meteorological Department.  Generalized and often incomplete information can be obtained from mostly US and European agencies and entities, but the inconsistent nature within and between these highly regarded meteorological centers has left me no choice but to omit their data.  These policies are currently being questioned by academia, businesses, and individuals within the country and abroad.  A slide show can be found at the end of the post for further information and action currently taking place.

The most widely used climate classification system, the Koppen-Geiger system was created in the latter part of the 19th century and has been expanded upon several times since.  In terms of scale, at best it could be considered effective on the meso level, however should probably be only considered at the macro-scale as seen above.

Zooming into the regional meso-scale it can be seen that Bangalore falls along the border of Highland Subtropical (CWb) and Humid Subtropical (CWa), however other sources have placed the city in a warm semi arid or tropical wet-dry regime. These definitive lines and descriptions are why it is important to consider all scales when describing a specific location.  As mentioned before historical analysis has shown that the city center has different weather patterns than the surrounding environments, a discrepency that continues to increase with continual urbanization.  

Sources:

GOOGLE EARTH. (n.d.).

Indian Institute of Science, Centre for Ecological Sciences. (n.d.). Study Area: Bangalore. Retrieved March 07, 2012, from ces.iisc.ernet.in: http://ces.iisc.ernet.in/energy/wetlands/sarea.html

Iyer, N. K., Kulkarni, S., & Raghavaswamy, V. (2007). ECONOMY, POPULATION AND URBAN SPRAWL A COMPARATIVE STUDY. Urban Population, Development and Environment Dynamics in , 1-37.

Kaspi, Y., & Schneider, T. (2012). Climate Dynamics of Earth and Other Planets. Retrieved April 01, 2012, from Tapio Schneider: http://www.gps.caltech.edu/~tapio/animations.html

Keller, E. A., & DeVecchio, D. E. (2012). Natural Hazards. Upper Saddle River: Pearson Prentice Hall.

Knox, P. L., & Marston, S. A. (2010). Human Geography: Places and Regions in Global Context. Upper Saddle River: Person Prentice Hall.

Lutgens, F. K., & Tarbuck, E. J. (2007). The Atmosphere: An introduction to meteorology. Upper Saddle River: Pearson Prentice Hall.

Manjaro, C. (2011, October 04). Air Pollution is Stunting India's Monsoon. Retrieved April 02, 2012, from The Watchers: http://thewatchers.adorraeli.com/2011/10/04/air-pollution-is-stunting-indias-monsoon/

McKnight, T. L., & Hess, D. (2008). Physical Geography: A landscape appreciation. Upper Saddle River: Pearson Prentice Hall.

National Data Centre. (n.d.). Monthly Mean Maximum & Minimum Temperature and Monthly Total Rainfall. Retrieved April 30, 2012, from India Meteorological Department: http://www.imd.gov.in/section/nhac/mean/110_new.htm

National Oceanic and Atmospheric Admininstration. (n.d.). Bangalore WMO:43295. Retrieved March 07, 2012, from dossier.ogp.noaa.gov: ftp://dossier.ogp.noaa.gov/GCOS/WMO-Normals/RA-II/IN/43295.TXT

NOAA. (n.d.). Climate Prediction Center. Retrieved April 01, 2012, from National Weather Service: http://www.cpc.ncep.noaa.gov/products/people/Kousky/Lectures/lecture-17-seasonal-cycle-monsoons-conv-zones.ppt.

Nybakken, J. W. (1997). Marine Biology: An Ecological Approach. Addison-Wesley Educational Publishers: Reading.

Peel, M. C. (n.d.). Spain. Retrieved April 30, 2012, from familypedia: http://familypedia.wikia.com/wiki/Spain

Srinath, P. (2012, March 24). Climate Data in India: Open and Closed. Retrieved April 30, 2012, from slideshare.net: http://www.slideshare.net/PavanSrinath/climate-data-in-india-open-and-closed

University of Wisconsin-Madison. (n.d.). Air Masses and Fronts. Retrieved April 01, 2012, from cimss.ssec.wisc.edu: http://cimss.ssec.wisc.edu/wxwise/class/frntmass.html

Ward, A. D., & Trimble, S. W. (2004). Environmental Hydrology. Boca Raton: CRC Press.

Withgott, J., & Brennan, S. (2008). Environment: The Science Behind the Stories. San Francisco: Pearson Benjamin Cummings.

Climate data in india - Open and Closed

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