Monday, February 7, 2011

Urban Heat Island in Pictures

This will be the first of a series of posts on urban heat island effect.

One of the things that I have become quite convinced of is that the urban heat island effect is vastly underestimated by the warmist hysteriacs. They underestimate the urban heat systematically and attack anyone who might question what they are doing. Anytime someone says that the urban heat island effect is tilting the data, giving an erroneously high temperature, the warmists always point to a chart done by NASA which shows that small and large towns are warming the same. Below is the chart.

This chart is trotted out as proof that the urban heat island is nothing to worry about. What they don't tell their readers is that both the green (rural) and red(urban) curves are highly edited and adjusted.

The warmists can believe that all they want to, but we are going to look at the temperatures inside urban areas vs the rural/natural area around the city and calculate the temperature difference between the city and the natural environment.

How will we do this? I went through the internet looking for published pictures of infrared pictures of the urban areas. Most of these have temperature scales so one can see what the temperature difference is.

As you look through these pictures remember what the IPCC says about the urban heat island effect. They say it is insignificant. Cities don't make much difference to the temperatures measured inside the cities. The infrared pictures, which measure temperature, tell a very different story. But first, what the IPCC says.

"Clearly, the urban heat island effect is a real climate change in urban areas, but is not representative of larger areas. Extensive tests have shown that the urban heat island effects are no more than about 0.05°C up to 1990 in the global temperature records used in this chapter to depict climate change. Thus we have assumed an uncertainty of zero in global land-surface air temperature in 1900 due to urbanisation, linearly increasing to 0.06°C (two standard deviations 0.12°C) in 2000.” Climate Change 2001:
Working Group I: The Scientific Basis
2.2 How Much is the World Warming?

So, what does that mean? The IPCC is correcting the data downward about 1/20th of a degree.

The IPCC says elsewhere

"Accordingly, this assessment adds the same level of urban warming uncertainty as in the TAR: 0.006°C per decade since 1900 for land, and 0.002°C per decade since 1900 for blended land with ocean, as ocean UHI is zero". Climate Change 2007: Working Group I: The Physical Science Basis” IPCC Fourth Assessment Report: Climate Change 2007

.006 deg C per decade over 100 years is a correction of only .06 deg C. This is a very very tiny correction. Remember this as we look at the pictures of the temperatures measured by the infrared thermal cameras. Let's start with Phoenix, Arizona.

Note that there is a 30 deg temperature difference between the countryside and the city center, and this picture is taken at night time. The web page this came from says:

"Over the two decades, as the Phoenix Metropolitan area has grown dramatically in size, the "urban heat island" effect has developed, which has caused temperatures in the center of the city to become much warmer than those on the outskirts of the valley. The concrete and asphalt of the city retains the heat of the day, and releases it slowly as compared to the surrounding desert terrain, which cools much quicker at night. The ASOS weather sensor has always been located near the Sky Harbor runway complex, and as the heat island effect intensifies, the nighttime lows at Phoenix keep rising every year. The summer of 2003 saw the all time record high minimum temperature at Phoenix (93 degrees) shattered as a new mark of 96 degrees was established! Several times during the summer the old mark of 93 was tied or broken, as well"

Note that the thermometer is at the airport. It is the bright yellow in this photo. Below is the actual picture of the weather station. Notice it isn't far from very hot cement runways.

The thermometer is located in the hottest place it could be placed in Phoenix. It is in the 30 deg C part of Phoenix. If the thermometer were out in the countryside, it would read significantly cooler. Yet the warmists claim that the urban heat island effect is miniscule. They claim that cities only heat the areas by .06 deg C, not the 30 deg clearly seen in the thermographs taken by infrared cameras. Clearly this is crazy.

Even peer-reviewed articles dispute the warmist claim. Jay S. Golden said:

The 0.86 F per decade warming rate for Phoenix is one of the highest in the world for a population of its size and can be compared with other cities to highlight the effects of rapid urbanization in the region. For example, Los Angeles’s rate was 0.8 F per decade; San Francisco, 0.2 F per decade; Tucson, 0.6 F per decade; Baltimore, 0.2 F per decade; Washington, 0.5 F per decade; Shanghai, 0.2 F per decade; and Tokyo, 0.6 F per decade .” Jay S. Golden, “The Built Environment Induced Urban Heat Island Effect in Rapidly Urbanizing Arid Regions – A Sustainable Urban Engineering Complexity,” Environmental Sciences, 1(2004):4,p. 321 – 349

Phoenix has the highest rate of warming in the world for cities of its size. Yet the warmists will tell you that that is not due to urbanization but due to CO2. That warming is .86 deg F, or .47 deg C per decade. 0.47 deg is half the warming claimed for the past 100 years!!! Below is a chart from Golden's article showing how Phoenix has warmed compared to a more rural area, Casa Grande National Monument about 30 miles south of Phoenix (not that the rural area has no heat island effect).

We will continue this in a couple of days. Just look at the thermal IR temperature measurements and you can see for yourself that the temperatures in the city center are much much hotter than the surrounding areas. A thermometer placed in the hottest spot in the city simply can't be unaffected by the radiation temperature of the surrounding landscape.

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