GLOTI

http://data.giss.nasa.gov/gistemp/

http://earthobservatory.nasa.gov/Features/WorldOfChange/decadaltemp.php
NASA usually up-dates GLOTI in the middle of each calendar month. NASA does not maintain a publicly accessible archive of previous editions of GLOTI. Only the most recent edition of GLOTI is available for the public to inspect at NASA's web site. NASA also publishes “Global Mean Estimates Based on Land-Surface Air Temperature Anomalies Only (Meteorological Station Data, dTs)”.

Thursday 26 January 2017

NASA's global temperature anomalies.

NASA publishes two sets of global temperatures, in the form of anomalies, for the period from January 1880 to the present. One of these sets is:-

Global Mean Estimates Based on Land-Surface Air Temperature Anomalies Only (Meteorological Station Data, dTs), which I shall abbreviate to “dTs”.

The other set is:- 

Combined Land-Surface Air and Sea-Surface Water Temperature Anomalies (Land-Ocean Temperature Index, LOTI), which is also known as the “Global Land-Ocean Temperature Index”, and which I shall abbreviate to GLOTI.

Both sets claim to show how the average temperature of the air at the surface of the earth, from pole to pole, has changed since 1880.

NASA currently uses the interval from 1951 to 1980 for the purpose of calculating global temperature anomalies, such that:-

The global temperature anomaly of January in year X is -1°C, if and only if, the average temperature of the air at the surface of the earth, from pole to pole, during January in year X is 1°C below the average temperature of the air at the surface of the earth from pole to pole, during the thirty Januarys between 1951 and 1980.

The global temperature anomaly of January in year Y is +1°C, if and only if, the average temperature of the air at the surface of the earth, from pole to pole, during January in year Y is 1°C above the average temperature of the air at the surface of the earth from pole to pole, during the thirty Januarys between 1951 and 1980.

The same applies mutatis mutandis for the remaining eleven months of the calendar year.

The annual global temperature anomaly of the January-to-December calendar year X is -1°C, if and only if, the average temperature of the air at the surface of the earth, from pole to pole, during year X is 1°C below the average temperature of the air at the surface of the earth, from pole to pole, during the thirty calendar years from 1951 to 1980.

The annual global temperature anomaly of the January-to-December calendar year Y is +1°C, if and only if, the average temperature of the air at the surface of the earth, from pole to pole, during year Y is 1°C above the average temperature of the air at the surface of the earth, from pole to pole, during the thirty calendar years from 1951 to 1980.
http://data.giss.nasa.gov/gistemp/faq/abs_temp.html

http://data.giss.nasa.gov/gistemp/