Sunday, November 22, 2009

Global Temperatures

Last Update: 01-18-2010

Below is a chart that some may find useful. It combines various global temperature estimates:
  • HadCRU3v: measurements from land stations + SST, starts in 1850, the reference period is 1961-1990. data link.
  • NASA GISS: measurements from land stations + SST, starts in 1880, the reference period is 1951-1980. data link.
  • NCDC: measurements from land stations + SST starts in 1880, the reference period is 1951-1980. data link.
  • UAH versions 5.2: satellite based measurements of the lower troposphere, starts in 1979, the reference period is 1979-2000. data available here.

Each dataset has a different reference period. A temperature offset is added to CRU, NCDC and UAH temperatures in order to represent the temperatures in a common reference period (1951-1980). The offset values are the following (in deg. C):
  • CRU: 0.0855
  • NCDC: -0.0330
  • UAH: 0.2425




Figure 1. Adjusted global temperature estimates. Click on the image to get a svg image.


Over the period 1979-2009, we can compute the median temperature value from the four estimates. The August median temperature measurement is +0.62 deg. C (98.2% of observed values are below).




Figure 2. (Red) median temperature estimate from 1979 to August 2009. (light yellow) range of temperature values; (yellow) 99% probability interval. The blue curve is the empirical CDF curve derived from all the datasets combined. Click on the image to get a svg image.

No comments:

Post a Comment