This post refers to my analysis of recorded monthly mean temperature trends at Port Blair in India. The station was established in 1868. The analysis used raw data (as recorded, without any adjustments) as published by KNMI (the Dutch Meteorological Institute). Polynomial curves of best fit were added to the plots.
Port Blair is a small city on Andaman Island in the Bay of Bengal.
Over the 1868-2016 period (a period of 149 years) the years are 92% complete.
Port Blair has a tropical monsoon climate, with little variation in temperature throughout the year. Mean monthly temperatures vary from 26.6 degC (in January) to 29.0 degC (in April). Extreme monthly mean temperatures recorded are 23.5 degC (in January 1977) to 31.4 degC (in April 1889).
Mean, Maximum and Minimum Monthly Temperatures
Plots are shown below for annual mean temperature and the monthly mean temperature for each of the 12 months. A polynomial trendline was fitted to each graph. A comparison of the monthy trendlines are also presented. It should be noted that the trendlines (in red) can sometimes be misleading at either end of the series as the line is very dependent on the temperature values in individual years (this sensitivity does not occur away from the start and end of the series).
Annual Mean Temperatures
Monthly Mean Temperature Trendlines
- The plots show long-period cyclical monthly trendlines in all months, with a High in about 1910 and a Low in about 1990.
- The monthly mean temperatures around 2000-2010 are between 0.5 degC and 1.5 degC lower than in around 1900.
- In most months there is a peak or plateau in the temperature trends around 2000-2010.
- There have been no alarming trends in temperatures in recent decades.
Port Blair is one of 257 stations, worldwide, for which I have analysed long-term temperature trends. The analyses at 50 representative stations are summarised in the blog post: world-50-temperatures
Please let me know what you think of my analyses. firstname.lastname@example.org
This article was written by Brian Gunter of Narooma, NSW, Australia. In his previous life Brian was an engineering hydrologist involved over many years in the analysis of rainfall and river flow data for the planning of water resources projects in Australia, Asia and Africa. In recent years he has been one of the Marine Rescue NSW (previously Royal Volunteer Coastal Patrol) volunteer weather observers who operate the Narooma station for the Australian Bureau of Meteorology.