“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.
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.
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| http://data.giss.nasa.gov/gistemp/faq/abs_temp.html |
