Comparison of NCEP CFSR versus NCDC Global Temperature Anomalies

The US National Center for Environmental Prediction (NCEP) has produced a Climate Forecast System Reanalysis (CFSR) based on “all available conventional and satellite observations”.  Most of these data were used to initialize real-time global weather forecast model runs four times each day since 1979.  This reanalysis can also be used to estimate annual global temperatures and temperature anomalies.  The University of Maine Climate Change Institute has compiled the CFSR data and provided an easy-to-use interface for viewing some of the data using maps and graphs with their Climate Reanalyzer web site.

I pulled CFSR annual global temperature anomaly data from the Climate Reanalyzer for 1979 through 2013 and added a compatible estimate for 2014 from the Weather Bell model temperature web page to complete the period 1979-2014.  I then graphed this data against the US National Climatic Data Center (NCDC) estimates based on the Global Historical Climate Network (GHCN) for the same period, as shown in Figure 1 below.  Both data sets have been normalized to the 1981-2010 period for comparison.

Figure 1. Comparison of NCEP CFSR versus NCDC estimates of annual global temperature anomalies from 1979 through 2014.

Figure 1. Comparison of NCEP CFSR versus NCDC estimates of annual global temperature anomalies from 1979 through 2014.

In general, the two approaches show a similar result, but there are some interesting differences.  These differences help to indicate some of the uncertainty in trying to estimate a global temperature anomaly as discussed in my previous post.  Of particular interest is the result for the most recent portion from 2001 through 2014.  The “pause” in the NCDC estimates is actually more of a peak and decline in the CFSR estimates.  The warmest years in the CFSR estimates are 2002-2003 and 2005-2007 with a peak in 2005.  In contrast, the warmest year estimated by NCDC is 2014.  In the CFSR data, 2014 ranks 12th for the 36-year period – far from being the “hottest year ever” as promoted by some.

Considering that the NCEP CFSR approach incorporates a much larger data set with much better spatial coverage for estimating global temperatures than the NCDC GHCN approach, I suspect the CFSR annual estimates are more accurate.

2 responses to “Comparison of NCEP CFSR versus NCDC Global Temperature Anomalies

  1. The chart shows clearly that the global temperature is rising slowly due to the increased activities that release CO2 emissions in the atmosphere and lead to global warming.
    Climate change is a real issue for our society and I hope that we will find a few responsible and powerful people who can really change something here.
    We can start as individuals by recycling our waste, by using green appliances at home, switching to LED lighting and so on.

  2. Mikey, the chart shows that global temperature may be rising slightly overall since 1979, but with an estimated uncertainty of at least 0.3C as I discussed in my previous post, we cannot have high confidence in this trend. Weather and climate are extremely complex. I am amazed at how well modern weather forecast model perform out a few days. However, long-range weather forecasts for years, months, or even weeks are totally unreliable. For this reason I have serious doubts how climate models trying to simulate conditions many years in advance can have any kind of accuracy other than pure random luck. I believe they are more a projection of the author’s views than anything else – little more than an opinion.

    That said, I do believe it is wise conserve energy and protect our environment as much as possible. In the long run, fossil fuels will run out and humanity will be forced to find alternatives. For this reason, I support the testing and development of alternative fuels, but I believe we need to continue to exploit our least expensive options to avoid unwarranted burdens on those who cannot afford more expensive alternatives.

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