Bias Toward Recording Higher Temperatures Fails To Produce More Extreme Records

SEARCH BLOG: CLIMATE

The following article appeared in ICECAP, by Joeseph D'Aleo:

United States and Global Data Integrity Issues

By Joseph D’Aleo, CCM, AMS Fellow

Issues with the United States and especially the global data bases make them inappropriate to use for trend analysis and thus any important policy decisions based on climate change. These issues include inadequate adjustments for urban data, bad instrument siting, use of instruments with proven biases that are not adjusted for, major global station dropout, an increase in missing monthly data and questionable adjustment practices.

NOAA NCDC USHCN - US CLIMATE DATA

When first implemented in 1990 as USHCN version1, it employed 1221 stations across the United States. In 1999, NASA’s James Hansen published this graph of USHCN version 1 annual mean temperatures:

About which Hansen correctly noted: “The U.S. has warmed during the past century, but the warming hardly exceeds year-to-year variability. Indeed, in the U.S. the warmest decade was the 1930s and the warmest year was 1934.”

USHCN was generally accepted as the world’s best data base of temperatures with the stations most continuous and stable, and adjustments made for time of observation, urbanization, known land use changes around sites, and instrumentation changes, each of which can produce major contamination issues for temperature data.

NOAA NCDC removed the urbanization adjustment of Karl et al (1988) in version 2 in 2007. GISS continues to adjust US data for urban heat islands using the satellite determined brightness which categorizes stations as rural, small towns and cities. Here is the latest GISS plot of the US temperatures.

 
See larger image here.

The difference between the NOAA NCDC USHCN version 2 and GISS shows that NOAA’s new algorithm fails to correct for urbanization warming. In fact the NCDC changes have introduced a warming of 0.75F in the 75 years since 1930. Man made warming indeed but the men are in Asheville, NC.

Read more at the link above.

I find this interesting because if all of the biases are toward higher recorded temperatures, why has there been a dramatic fall-off of new record high temperatures in this decade, as shown in my recent posts? Given these biases, perhaps the real story is that we are experiencing more rapid cooling than has been reported.

Also see article in Anthony Watts' blog.  HT: I'm Hernadi-Key 

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