USHCN

New NOAA data show cooling trend for last 10 years

The National Oceanic and Atmospheric Administration (NOAA) maintains an official temperature record for the United States through its network of weather stations called the U.S. Historical Climatology Network (USHCN). There are many problems with this network including instrumental errors and siting in or near urban areas which subject the stations to the artificial warming of the urban heat island effect.

A local example of change in site conditions is illustrated by the USHCN station on the campus of the University of Arizona. The first photo below shows how it looked in 1923 – in a relatively open area. The more recent second photo shows how the station is now surrounded by buildings, asphalt streets and parking lots. The site change is the main reason why the station reports warmer temperatures than in the past.

Tucson1923

tucson_uofaz3

The official temperatures reported by the National Weather Service currently come from a station at Tucson airport which is, itself, surrounded by concrete and asphalt.

NOAA has also established a parallel set of weather stations, operating for about 10 years now, that address the many problems of the USHCN. That network is the United States Climate Reference Network (USCRN). These are modern stations, sited well away from urban influence, that use state of the art instrumentation and are therefore not subject to many of the problems associated with the old USHCN network.

NOAA has just released the data from the 114 stations of the new USCRN. The difference in temperatures recorded by the two networks shows that the old USHCN has been overstating the temperature anywhere from +0.5°C on average, up to almost +4.0°C (+0.9°F to +7.2°F) in some locations during the summer months. Remember that when you see headlines blaring that a certain day, week, month, year was the warmest since…. whenever. The new USCRN data is more in line with the satellite temperature record.

The following graph is a temperature anomaly plot from the new network (Fahrenheit on left scale, Celsius on right). There have been heat waves and cold spells, but the overall trend is one of cooling for the past 10 years.

USCRN temps US

Plots of maximum temperatures and minimum temperatures also show a cooling trend.

Anthony Watts has a long post with detailed explanations and nice graphics on his WUWT blog.

The point here is that much of the “global warming” reported in the media is an artifact of spurious temperatures from an obsolete network of weather stations.

P.S. Do you think you will ever see this story in the Arizona Daily Star?

See also more articles about the old USHCN network and “adjustments” made to its data:

NOAA Temperature Record “Adjustments” Could Account for Almost All “Warming” since 1973

US Temperature Trends Show a Spurious Doubling Due to Noaa Station Siting Problems and Post Measurement Adjustments Says a New Study

NOAA experiment shows US temperatures not as warm as reported

The National Oceanic and Atmospheric Administration (NOAA) maintains an official temperature record for the United States through its network of weather stations called U.S. Historical Climatology Network (USHCN). There are many problems with this network including instrumental errors and siting in or near urban areas where stations are subject to the artificial warming of the urban heat island effect. These problems have been documented here, here, and here.

NOAA has also established a parallel set of weather stations, operating for about 10 years now, that address the many problems of the USHCN. That network is United States Climate Reference Network (USCRN). These are modern stations, sited well away from urban influence, that use state of the art instrumentation and are therefore not subject to the problems associated with the old USHCN network.

The difference in temperatures recorded by the two networks shows that the old USHCN has been overstating the temperature anywhere from +0.5°C on average, up to almost +4.0°C (+0.9°F to +7.2°F) in some locations during the summer months. Remember that when you see headlines blaring that a certain day, week,  month, year was the warmest since…. whenever. The new USCRN data is more in line with the satellite temperature record.

The situation is neatly summed up by C3Healines (in spite of its provocative headline):

NOAA Conducts Large-Scale Experiment And Proves Global Warming Skeptics Correct

 NOAA sitesMost global warming skeptics believe that humans have some measurable impact on global temperatures and the climate, but that natural climate forces, over longer periods, will overwhelm the human influence. In addition, skeptics believe that the human influence will not result in the hysterical catastrophic climate disasters presented by doomsday pundits. And finally, global warming skeptics believe, for a multitude of reasons, human errors/mistakes/failings have caused late 20th century global warming to be significantly overstated.

This article addresses this last point. What if the climate experts conducted an actual experiment that would prove whether the global warming skeptics were right or wrong about world-wide warming being overstated? ( click to get larger image at source: one, two, three )

Well, NOAA has actually conducted said experiment by building their U.S. Climate Reference Network (USCRN), which precisely, and automatically, measures temperature and weather conditions across the U.S. The USCRN effort is based on the concept that the best way to measure the impact of greenhouse gases on global temperatures is to place state-of-the-art climate stations in pristine rural areas that are little impacted by people, buildings, vehicles, equipment, asphalt and etc.

An example of one of NOAA’s pristine climate measurement stations is the top image (Image #1). And the middle image depicts the location of each pristine station – there are currently 114 of them, and clearly they are well dispersed providing good U.S. coverage.

By carefully planning and maintaining these pristine stations and by using the best technology available, this large-scale experiment eliminates the following problems with the older weather measurement network:

There are no observer or transcription errors to correct.

There is no time of observation bias, nor need for correction of it.

There is no broad scale missing data, requiring filling in data from potentially bad surrounding stations.

There are no needs for bias adjustments for equipment types since all equipment is identical.

There is no need for urbanization adjustments, since all stations are rural and well sited.

There are no regular sensor errors due to air aspiration and triple redundant lab grade sensors. Any errors detected in one sensor are identified and managed by two others, ensuring quality data.

Due to the near perfect geospatial distribution of stations in the USA, there isn’t a need for gridding to get a national average temperature.

So, what has this NOAA experiment found? The bottom image (Image #3) tells that story – when compared to measurements from the old, inaccurate, non-pristine network, temperature “warming” in the U.S. is being overstated anywhere from +0.5°C on average, up to almost +4.0°C (+0.9°F to +7.2°F) in some locations during the summer months.

To clarify, this range of overstatement depends on the given new and old stations being compared. However, when the new network versus old network results are examined in total, for the recent summer heat wave in the U.S., the old stations were reporting bogus warming during July that amounted to some +2.1°F higher than the actual temperatures.

What does this mean? Within the climate science realm, the old climate/weather station system had long been considered the best and most complete measurement network in the world. But when pitted against a brand new climate measurement system that has the best qualities that science can provide, we find that the traditional U.S. methodology is significantly overstating the “global warming” phenomenon. This means that if other countries replaced their own low quality network with NOAA’s greatest and latest technology, with the best location site standards applied, we would discover that world-wide temperature increases have been wildly overstated also.

Conclusions: A large-scale NOAA experiment has proven that global warming skeptics were correct: temperature warming in the U.S. has been significantly overstated in recent decades. This NOAA experiment should be expanded to other continents and countries since it is now obvious that the combined older technology and substandard weather station sites have well overstated the global warming phenomenon. Before any further dollars are spent on climate change adaptation and/or mitigation, the world needs to upgrade their global weather/climate reporting network to the USCRN standard so that policymakers have correct temperature change measurements to base their decisions on.

Those who claim that human carbon dioxide emissions are the major cause of recent warming (AGW) fail to produce physical evidence to support that position. Some cite computer statistical studies that conclude that a certain percentage of the warming must be due to human influence, only because they can’t think of anything else. The bottom line, however, is that computer simulations are not physical evidence and the AGW position is unsupported by anything other than speculation. Government policies designed to reduce carbon dioxide emissions therefore have no basis in science, no proof that such policies would make a real difference in climate. But such policies have a great detrimental effect on our economy, jobs, and national security. This phantom menace should be put to rest so that we can direct our resources toward solving real problems.

See also:

Which comes first, rise in global CO2 or rise in global temperature?

NOAA temperature record “adjustments” could account for almost all “warming” since 1973

July 2012 not hottest according to NOAA data

US Temperature trends show a spurious doubling says Anthony Watts

Urban heat island effect on temperatures, a tale of two cities

Most US maximum temperature records set in the 1930s

The State of our Surface Temperature Records

NOAA temperature record “adjustments” could account for almost all “warming” since 1973

Dr. Roy Spencer, Principal Research Scientist at the University of Alabama in Huntsville, analyzed the records of weather stations in the U.S. Historical Climatology Network (USHCN) which NOAA touts as the official U.S. climate record. He found that almost all of the reported warming since 1973 can be accounted for merely by the adjustments to the record made by NOAA.

Spencer also analyzed the British CRUTem3 and International Surface Hourly (ISH) data. His main conclusions are:

1) The linear warming trend during 1973-2012 is greatest in USHCN (+0.245 C/decade), followed by CRUTem3 (+0.198 C/decade), then my ISH population density adjusted temperatures as a distant third (+0.013 C/decade)

2) Virtually all of the USHCN warming since 1973 appears to be the result of adjustments NOAA has made to the data, mainly in the 1995-97 time frame.

3) While there seems to be some residual Urban Heat Island (UHI) effect in the U.S. Midwest, and even some spurious cooling with population density in the Southwest, for all of the 1,200 USHCN stations together there is little correlation between station temperature trends and population density.

4) Despite homogeneity adjustments in the USHCN record to increase agreement between neighboring stations, USHCN trends are actually noisier than what I get using 4x per day ISH temperatures and a simple UHI correction.

When “global warming” only shows up after the data are adjusted, one can understand why so many people are suspicious of the adjustments.

See his post on the matter here.

Spencer has also examined the surface temperature records according to the population density near the stations. He finds “clear evidence of an urban heat island effect on temperature trends in the U.S. surface station network” which produce a warming bias to station records.

See his posts here and here.

Among his findings:

1) Essentially all of the +0.20 deg. C/decade average warming trend over the U.S. in the last 40 years computed from the CRUTem3 dataset (which the IPCC relies upon for its official global warming pronouncements) evaporates after population adjustment (no claim is made for countries other than the U.S.)

2) Even without any adjustments, the ISH data have a 20% lower warming trend than the CRUTem3 data, a curious result since the CRUTem3 dataset is supposedly adjusted for urban heat island effects.

Comment: These analyses may explain, in part, why the official surface temperature record does not agree with the record from satellites. It also implies that recent warming is not nearly as dire as some would have us believe, nor does the real temperature reflect any major influence by carbon dioxide emissions.

NOAA is not the only agency “adjusting” the temperature record. NASA’s GISS has been doing that for U.S. and global temperatures also (for instance see here.)

All the adjustments tend to make older temperatures, for example, those in the 1930s, colder while making all more recent temperatures warmer. This is statistically improbable if the adjustments were to be justified by some physical conditions. This whole process is troubling because it suggests corruption within the government-funded scientific establishment whose results apparently have to be politically correct rather than scientifically correct.

 

See also:

A Perspective on Climate Change a tutorial

NOAA accused of fabricating temperature data

The State of our Surface Temperature Records