19th Conference on Climate Variability and Change


Detection of a Global and Caribbean climate changes

Nazario D. Ramirez, University of Puerto Rico, Mayaguez, Puerto Rico; and O. Julca and J. Gonzalez

Climate variability which is not forced by external factors is known as internal climate variability and occurs at all times from weeks to centuries. External factors that force climate variations are due to natural and anthropogenic causes, such as solar radiation, volcanic eruption, and increasing concentration of greenhouse gases. Climate change detection is the procedure to determine when an observed climate behavior differs significantly from the internal natural variability.

The North Hemisphere and the major Caribbean islands have shown a significant increment of minimum air temperature in 1998. A sequential statistical test shows that the temperature trends over the North Hemisphere started in 1970 while in the Caribbean started in 1995. Monthly data were obtained from Goddard Institute for space Studies (1880-2004), cooperative observed network (1948-2005), global historical climatology network (1948-2005) and from NCEP/NCAR reanalysis data (1948-2005).

The global sea level time series shows a positive linear trend with an average increment of about 3 mm per year, while the Caribbean does not exhibit a trend. The sea levels at global and Caribbean regional scale have shown a significant increment at the same point in time1998. The studied data was obtained from TOPEX Microwave Radiometer and Jason satellite observations from 1992 to 2005.

A sequential statistical test has been introduced to detect when as significant climate change has occurred. The test is very simple and efficient and consists of removing the autocorrelation structure of the process and determines when the fingerprint of the process exhibits a significant change. The major contribution of this work is to introduce a tool to determine without ambiguity when a climate change occurs.

extended abstract  Extended Abstract (372K)

wrf recording  Recorded presentation

Session 3, Detection and attribution of regional climate change
Tuesday, 16 January 2007, 8:30 AM-12:00 PM, 214B

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