Pacific Ocean Islands Temperatures

Published data were used to analyse the long-term annual temperature trends at eight locations located in the Pacific ocean.   Stations selected were located in Palau, Caroline Islands, Hawaii, Samoa, Cook Islands, Tahiti and Chile

The data used were all from the website of KNMI (the Royal Netherlands Meteorological Institute). Only raw data were used (ie as originally recorded, without any adjustments). Data were all used from stations located in rural areas or in small towns so as to avoid the possible influence of urbanisation on the temperatures.

map-pacificocean

table-pacificocean

The periods of the data ranged from 77 years to 103 years of complete annual data.  The earliest record, at Apia, commenced in 1890.

The plots shown below are of the annual mean temperatures at each of the eight locations. On each plot a polynomial “best fit” trendline has been added. It should be noted that the trendlines near each extremity (ie near the start and end of the records) are quite sensitive to individual data points, whereas trendlines within the main body of the record are much more stable and reliable.

 

COMPARISON OF TRENDLINES

Annual Mean Temperature Trends

[ The basis of these trendlines can be seen from the analyses for the eight individual stations – see next section. ]

pacificislands-annual

Annual Mean Temperature Residual Trends

[ The individual trend-lines have been adjusted by constant amounts to be approximately zero at the trend-lines in 1970.

pacificislands-residual

 

 

ANNUAL MEAN TEMPERATURE TRENDS FOR INDIVIDUAL STATIONS

Koror (Palau) 1924-2015

koror

 

Yap (Caroline Islands) 1922-2015

yap

Lihue (Hawaii, USA) 1905-2015

lihue

 

Hilo (Hawaii, USA) 1906-2015

hilo

 

Apia (Samoa) 1890-1989

apia

 

Rarotonga (Cook Islands) 1907-1999

rarotonga

 

Faaa (Tahiti) 1935-2014

faaa

 

Isla Juan Fernandez (Chile) 1901-2014

islajuanfernandez

 

 

DISCUSSION AND COMMENTS

  • The data analysed was limited to that which were available on the KNMI website.
  • The annual mean temperature trend-lines for the eight stations located on Pacific Ocean islands generally showed weak cyclical patterns.
  • Faaa has a strong cyclical pattern with Highs around 1920 and 2000 and a Low around 1970.
  • Lihue temperatures have increased steadily by about 2 degC since 1910.
  • Isla Juan Fernandez temperatures have decreased steadily by about 1 degc since 1910.
  • Apart from Faaa there is no strong indication of a peak in the temperature trend around 2000.

 

CONCLUSIONS

  • The trend-lines for the eight stations were generally weakly cyclical.
  • Faaa has a strong cyclical pattern with Highs around 1920 and 2000 and a Low around 1970.
  • The temperature rise between around 1970 and around 2010 was generally 0.0-1.0 deg C.

 

The Author:

This article was written by Brian Gunter of Narooma, NSW. 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 Bureau of Meteorology.

 

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