And are those temperatures based on the Canadian data collection, or on the US revised to fit our program model?
.
HadCRUT is the
dataset of monthly
instrumental temperature records formed by combining the sea surface temperature records compiled by the
Hadley Centre of the UK
Met Office and the land surface air temperature records compiled by the
Climatic Research Unit (CRU) of the
University of East Anglia.
The data is provided on a grid of boxes covering the globe, with values provided for only those boxes containing temperature observations in a particular month and year.
Interpolation is not applied to infill missing values. The
first version of HadCRUT initially spanned the period 1881–1993, and this was later extended to begin in 1850 and to be regularly updated to the current year/month in near
real-time.
HadCRUT4 was
introduced in March 2012. It "includes the addition of newly digitised measurement data, both over land and sea, new sea-surface temperature bias adjustments and a more comprehensive error model for describing uncertainties in sea-surface temperature measurements". Overall, the net effect of HadCRUT4 versus HadCRUT3 is an increase in the average temperature anomaly, especially around 1950 and 1855, and less significantly around 1925 and 2005.
The
Climatic Research Unit had as an early priority the objective of filling gaps in available information "to establish the past record of climate over as much of the world as possible, as far back in time as was feasible, and in enough detail to recognise and establish the basic processes, interactions, and evolutions in the Earth's fluid envelopes and those involving the Earth's crust and its vegetation cover". Through the 1970s the unit worked on interpreting documentary historical records. From 1978 onward CRU began production of its gridded
data set of land air temperature anomalies based on
instrumental temperature records held by
National Meteorological Organisations around the world. In 1986 sea temperatures were added to form a synthesis of data which was the first global temperature record, demonstrating unequivocally that the globe has warmed by almost 0.8°C over the last 157 years. From 1989 this work proceeded in conjunction with the
Met Office Hadley Centre for Climate Prediction and Research, and their work demonstrated
global warming of almost 0.8°C over the last 157 years.
Access to weather station temperature records was often under formal or informal confidentiality agreements that restricted use of this raw data to academic purposes. From the 1990s onwards the unit received requests for this weather station temperature data from people who hoped to independently verify the impact of various adjustments, and after the
UK Freedom of Information Act (FOIA) came into effect in 2005, there were
Freedom of Information requests to the Climatic Research Unit for this raw data. On 12 August 2009 CRU announced that they were seeking permission to waive these restrictions, and on 24 November 2009 the university stated that over 95% of the CRU weather station temperature data set had already been available for several years, with the remainder to be released when permissions were obtained. In a decision announced on 27 July 2011 the
Information Commissioner's Office (ICO) required release of raw data even though permissions had not been obtained or in one instance had been refused, and on 27 July 2011 CRU announced release of the raw temperature data not already in the public domain, with the exception of Poland which was outside the area covered by the FOIA request.
https://en.wikipedia.org/wiki/HadCRUT
Because it takes some time for the oceans to warm up and cool down, there is a delay before the peak in solar activity shows itself in the earth’s temperature. The
best measure we have of global temperatures is made by satellites. Here is a picture of how temperatures have changed in the satellite age.
Notice there is no one to one correspondence to temperature deviation with increasing CO2 levels, in reality? Why is that?
