Changes

:* The final one is at [[NASA]] (GISS), the Goddard Institute for Space Studies.  

:* The final one is at [[NASA]] (GISS), the Goddard Institute for Space Studies.  

The three groups take raw data, and they "homogenize" it to remove things like when a station was moved to a warmer location. The three global temperature records are usually called CRU, GISS, and GHCN. Both GISS and CRU, however, get almost all of their raw data from GHCN. All three produce very similar global historical temperature records from the raw data. One of the things that was revealed in the released CRU emails is that the CRU basically uses the Global Historical Climate Network (GHCN) data set for its raw data.<ref>[http://www.climate-gate.org/search.php?keyword=GHCN&topEmails=&submit=Search Search - GHCN], climate-gate.org, Climategate Document Database.</ref> But the [[IPCC]] uses the "adjusted" data; GHCN adjusts the data to remove what it calls "inhomogeneities." Inhomogeneity are defined in a quote from GHCN:

The three groups take raw data, and they "homogenize" it to remove things like when a station was moved to a warmer location. The three global temperature records are usually called CRU, GISS, and GHCN. Both GISS and CRU, however, get almost all of their raw data from GHCN. All three produce very similar global historical temperature records from the raw data. One of the things that was revealed in the released CRU emails is that the CRU basically uses the Global Historical Climate Network (GHCN) data set for its raw data.<ref>[http://www.climate-gate.org/search.php?keyword=GHCN&topEmails=&submit=Search Search - GHCN], climate-gate.org, Climategate Document Database.</ref> But the [[IPCC]] uses the "adjusted" data; GHCN adjusts the data to remove what it calls "inhomogeneities." The term "inhomogeneity" is defined in a quote from GHCN:

{{cquote|Most long-term climate stations have undergone changes that make a time series of their observations inhomogeneous. There are many causes for the discontinuities, including changes in instruments, shelters, the environment around the shelter, the location of the station, the time of observation, and the method used to calculate mean temperature. Often several of these occur at the same time, as is often the case with the introduction of automatic weather stations that is occurring in many parts of the world. Before one can reliably use such climate data for analysis of long term climate change, adjustments are needed to compensate for the non-climatic discontinuities.<ref name=dataintegrity/>}}  

{{cquote|Most long-term climate stations have undergone changes that make a time series of their observations inhomogeneous. There are many causes for the discontinuities, including changes in instruments, shelters, the environment around the shelter, the location of the station, the time of observation, and the method used to calculate mean temperature. Often several of these occur at the same time, as is often the case with the introduction of automatic weather stations that is occurring in many parts of the world. Before one can reliably use such climate data for analysis of long term climate change, adjustments are needed to compensate for the non-climatic discontinuities.<ref name=dataintegrity/>}}  

At Darwin Airport there are five separate individual station records that are combined to make up the final Darwin record.<ref>[http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=0&name=darwin GISS Surface Temperature Analysis], data.giss.nasa.gov.</ref> This raw data is downloaded from GISS, but GISS uses the GHCN raw data as the starting point for their analysis. Before the GHCN homogenized the data, temperatures in Darwin were falling at 0.7 Celcius per century. After the homogenization, they were warming at 1.2 Celcius per century.  

At Darwin Airport there are five separate individual station records that are combined to make up the final Darwin record.<ref>[http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=0&name=darwin GISS Surface Temperature Analysis], data.giss.nasa.gov.</ref> This raw data is downloaded from GISS, but GISS uses the GHCN raw data as the starting point for their analysis. Before the GHCN homogenized the data, temperatures in Darwin were falling at 0.7 Celcius per century. After the homogenization, they were warming at 1.2 Celcius per century.