Monday, September 7, 2015

US In A Cooling Trend - Winters Much Colder

Subtitle: USCRN Temperatures Are Declining Rapidly 


An analysis of atmospheric temperature data from 55 pristine United States locations show a pronounced annual cooling trend of minus 2.68 degrees Celsius per century over the ten-year period 2005-2014.   The Winter cooling trend for the 55 locations is much greater at minus 10.86 degrees Celsius per century.   The region with the most rapid Winter cooling is the MidWest and Northern Plains at minus 23.1 degrees Celsius per century.  All regions have a cooling for Winter months.  All regions but one, the West and Mountains, also have a pronounced annual cooling.  

Data Source

Data for this study were obtained from United States Climate Reference Network, USCRN   see link .   This is part of the National Oceanic and Atmospheric Administration, the National Climate Data Center. 

Map of USCRN Stations and view of a typical station
From NOAA’s website:  “The U.S. Climate Reference Network (USCRN) is a system of climate observing stations developed by the National Oceanic and Atmospheric Administration (NOAA). The USCRN's primary goal is to provide long-term temperature, precipitation, and soil moisture and temperature observations that are of high quality and are taken in stable settings.”  At this time, “the network consists of 114 commissioned stations in the contiguous United States, 16 stations in Alaska (with a plan to eventually have a total of 29), and 2 stations in Hawaii.”  As an aside, there are a surprising number of stations located in Alabama, with 20 at this time.   Meanwhile, Mississippi has only two, and Arkansas has only one station.  Tennessee has one station.   One wonders what could possibly justify placing 20 stations in Alabama.   Also, there are 24 stations in New Mexico, and again one wonders what could be the justification.   Utah has 19 stations, while Wisconsin has only one.  

By “stable settings,” NOAA means that the locations are far from human warming influences such as cities, airports, and industries, and are expected to not have their present conditions change over the next several decades.    The stations have automatic sensors, redundancy, and automatic data upload to computer databases.   The intent is to have reliable, unbiased data without gaps and relocation issues.
The oldest station began operating in July, 2001 in Asheville, North Carolina.   The next-oldest station began operating in January, 2002 in Kingston, Rhode Island.    By December of 2004, 60 stations were operating.  Of those, 55 stations were selected for this study.  


Data from United States Climate Reference Network, USCRN, for the decade beginning January, 2005 and ending December, 2014 were analyzed for overall and regional temperature trends.  Monthly average temperatures were used.  The monthly averages were themselves averaged to obtain annual averages.   Annual linear trends were calculated.  Only 55 locations were used in this analysis, because no additional USCRN stations had records extending to or before January, 2005.  Where duplicate stations exist at the same site, only one station of each pair was chosen.   One state, Colorado, has 5 stations of suitable length but these were considered too many for the state’s size.  Therefore, only two of the stations were included in the data set.

In addition to the annual trends, averages and linear trends were determined for Winter months of December, January, and February.  This required obtaining data for December, 2004 for all 55 locations.   Therefore, the span of the data in this analysis is December, 2004 through and including December, 2014. 

Averages and trends for regions were also determined.   Four regions were defined as 1) MidWest and North, 2) South and Southwest, 3) Atlantic, and 4) West and Mountain.  

The intent of the analysis was to look at the data for a recent decade during which other temperature datasets show no increase in global average temperature.  However, other datasets suffer from inclusion of data from urban areas with known urban heat island effects that produce an artificial warming trend.   In contrast, the USCRN stations are purposely located far from such urban heat influences.   It was expected that one of three possible outcomes would emerge: 1) no trend at all, 2) a warming trend, or 3) a cooling trend.    A result showing no trend would be consistent with datasets mentioned above.  A result showing a warming trend would be consistent with the widely-discussed carbon-dioxide Greenhouse Gas hypothesis that allegedly creates an overall warming, or global warming.  (see e.g. the International Panel on Climate Change reports, IPCC)   A result showing a cooling trend would be consistent with falsifying the carbon-dioxide Greenhouse Gas hypothesis, and confirming the impact of natural cycles on global temperatures.  

Results for annual, and Winter months are shown below (see Table 1).  The annual cooling trend for all 55 stations is minus 2.68 degrees C per century.   The trend for Winter months is minus 10.86 degrees C per Century.  A graphical result is shown in Figure 1, above. 

    Annual Average Trend
    Degrees Celsius / Century

Winter Months Trend
Degrees Celsius / Century 
All Stations  55
MW and N 15
SO and SW 12
ATL  10
W and MT  18

Table 1  Summary of Results 2005-2014

It is not surprising that temperature trends from non-urban data show a cooling, when other datasets that include urban areas show no trend over the same period.  It is logical that a zero trend is the result of some data with a warming trend, and off-setting data with a cooling trend.  These USCRN stations show the cooling trend that many have long suspected.
Among these 55 data points, none have exactly zero trend, although Goodwell, OK, is close at minus 0.04 degrees C per Century.    There are five stations, approximately ten percent of the total, that have a trend of less than 1 degree C per Century, positive or negative. Those five stations are located in South Carolina, North Carolina, Washington state, Oklahoma, and upstate New York.  It is noteworthy that none of the almost-zero trend stations are located in the rapidly-cooling North and MidWest region.  

Regional trends 

N and MW Region Winter Trend
The most eye-catching result is the rapid cooling trend for the North and MidWest region, Winter months, of minus 23.1 degrees C per century (see Table 1, and graph).  The annual trend for the same region is also a rapid cooling of minus 11.24 degrees C per century.     The severity of such cooling would be alarming, if the trend were to continue.  The North and MidWest parts of the US are vital to the economy, especially in agriculture and cattle.   Colder and longer winters would prevent farmers from producing the usual crops and yields.   Furthermore, such cooling would prevent snow from melting each Summer, leading to frozen ground and glaciers.   Year-round snow acts to increase the reflection of solar energy, or increased albedo, which leads to cooler temperatures and yet more snow. 

Stations with the most rapidly-cooling trends include:

Sioux Falls, South Dakota  minus 32 degrees C per century
Medorah, North Dakota      minus 31 degrees C per century
Goodridge, Minnesota        minus 30 degrees C per century
Buffalo, South Dakota        minus 28 degrees C per century
Wolf Point, Montana           minus 24 degrees C per century


Critics might point out that not all the available data was used in the analysis, as if that might make the conclusions invalid.   However, it must be understood that over-inclusion of data leads to erroneous conclusions.    For example, including 5 stations for Colorado, but only 3 for California would skew the results in favor of Colorado.  

Another criticism might be the choice of data to replace missing data points.  In this dataset, there were relatively few missing data points.  However, almost every station had one missing data point, with some stations missing two or three data points.   Care was taken to examine the data graphically to ensure the replacement data fell along a smooth curve.  

Critics might also point out that conclusions based on a 10-year analysis of climate temperature data is almost meaningless since climate changes slowly over several decades and centuries.   The author’s response is that valid conclusions can be drawn from a 10-year analysis, especially if the major conclusion is that a serious problem may develop soon, or may already be occurring.   From this analysis, it certainly would be prudent to observe closely the winters for the next few years, especially in the North and MidWest region.  However, all the regions encompassed in this study show a cooling trend for the Winter months of Dec-Jan-Feb.   Only the Atlantic region has a modest Winter cooling trend, which might be due to having only a few stations in that region for this analysis. 

Also, all regions except the West and Mountains show an annual cooling trend.  It is likely that the recent multi-year drought in the West and Mountains are responsible for the slight warming trend.   


The long-term temperature datasets have several known deficiencies, among those are the inclusion of urban heat islands such as large cities.  Those datasets are also adjusted repeatedly, with each new report with adjusted data claimed to be accurate.   In addition, those datasets suffer from many missing data records that require some means to insert data.  They also suffer from disjointed data due to station moves to different locations.   The USCRN data is intended to provide data with none of those deficiencies, being located far from human influences, using state-of-the-art electronic measurement devices, redundant devices, automated data collection and uploading to computers, and not being moved around every few years.    
Goodridge, California temperatures sorted by population

An earlier analysis by James Goodridge found that essentially zero warming occurred in California counties with low population, over an 85-year period from 1909 to 1994.  Yet, counties with high populations experienced warming of almost 2 degrees Celsius per century.   (Goodridge, J.D. (1996) Comments on “Regional Simulations of Greenhouse Warming including Natural Variability” . Bull, Amer. Meteorological Society 77:1588-1599.)   See chart at right (Urban Heat Island Effect)  for the results.

What this present analysis of the USCRN 55 stations shows is that not only are pristine locations not warming, they are actually cooling. 

Regional trends also show substantial cooling.   

While the time period of this study is necessarily short by climate research standards, it is prudent to pay close attention to the northern tier of states in the US, especially the next few winters.   

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2015 by Roger Sowell all rights reserved

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