Sunday, November 29, 2015

Cities and UHI Urban Heat Islands

Subtitle: Cities and UHI Warming Corrupt Temperature Databases

Much is made over the average global climate,with some insisting the Earth is warming at unprecedented rates, others not so sure, and many convinced that there is zero cause for alarm because the climate scientists who are in charge of the temperature data made various errors.   This article explores an aspect of the third category, a serious error in the temperature data that makes any claims of catastrophic warming moot.  
Lone skyscraper in Oxnard, California

The essential concept is that cities, many of them very large, are included in the temperature database that the scientists use.   Most of the cities show a rapid warming, which is well-known and named the Urban Heat Island effect (UHI).   The UHI is due to the energy consumed in a city that must be dissipated, plus the absorption of solar energy by the land area that must also be dissipated.   Each of these is described below. 

Cities have energy consumption for a multitude of purposes, including but not limited to building heating, building cooling via air-conditioning, lighting, home and restaurant use such as cooking and heating water, electronics operation, vehicles used in transportation, commercial and industrial use, airports, train operations, and seaports.   Energy is also consumed in construction and demolition activities.   Much of this energy is in the form of electricity, some is from burning fuels such as coal, home heating oil, propane, and natural gas, and some is from transportation fuels including gasoline, jet fuel, diesel fuel, and fuel oil for ships.  From first principles of thermodynamics, all of the energy consumed, or input into the system, must be either stored or rejected to a heat sink.   Engineers will recognize the First Law, which states Energy In = Energy Out plus Accumulation, where Accumulation may be positive or negative.  Where Accumulation is zero, then Energy In = Energy Out.   The ways that this energy is dissipated, or the Energy Out component of the First Law, are explored next. 

A city, being comprised of static elements (buildings, roads, and such) plus dynamic elements (people moving, vehicles moving, machinery moving and such) can dissipate heat energy in all of the three ways of energy transfer.  Those three ways are by conduction, by convection, and by radiation.   Here, radiation refers not to nuclear ionizing radiation but to heat transfer by electromagnetic radiation in the infra-red spectrum, what is commonly known as radiant heat.    Conduction is the transfer of heat from one body to another by direct contact between the two.  A city has direct contact with the land below the city, to some extent with water if that is a part of the city, and the air above the city.  On a long-term basis, the amount of heat removed via conduction can be considered a very small fraction of the total Energy Out.    Convection is defined as heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it.  In a city, this would be primarily air blowing past buildings, either by natural wind, thermal air currents, or forced air in some cases.   Convection is a significant fraction of total Energy Out in a city.  Finally, radiation is the third and significant form of heat transfer in the total Energy Out in a city.   

A city can be considered as a collection of vertical heated objects, buildings, that have energy input that must ultimately be rejected as described above.   If the energy input is not dissipated or rejected, First Law requires that the buildings will have ever-increasing temperature.  We know that this does not happen, therefore the energy is dissipated.   One can consider the simple case of a single building on a flat prairie, where the building has 20 floors and stands approximately 200 feet above the prairie.   Such a building is shown nearby, a blue-exterior, 22-story building in Oxnard, California, the Financial Plaza Tower.   The important aspect of a lone, single building is that radiant energy is free to flow from the building in all directions.   The Financial Plaza Tower does have another, smaller building a few blocks away, so that radiant energy in that direction is somewhat impeded.   

However, if one considers multiple tall buildings in close proximity to each other, such as occurs in many large cities, the radiant heat cannot escape each building very quickly.  Instead, the Stefan-Boltzmann equation for radiative heat transfer (see below) requires that each building shields its neighbors, or bounces the heat back and forth.  Only the buildings at the perimeter can radiate heat freely, and then only in the direction away from the other buildings.   Thus, a collection of tall buildings in cities must reject their heat primarily via convection.   One can experience this first-hand by visiting a city on a warm day with very little wind.   The heat accumulates rapidly.  Even at night, again with no wind, a city will have warmer temperatures than average.   (Aside and personal note, even though anecdotal, I worked for some time in downtown areas of Dallas, Texas, and in Los Angeles, California and experienced the zero-wind high temperatures both in the day and after dark.   The same occurs in other cities I have visited.  The phenomenon is real and easily observed.) 

(Note on Stefan-Boltzmann equation:  

Net Radiated Energy per second, E = k A (Th^4-Tc^4)  

where k is a constant, A is surface area of the radiating surface, Th is temperature of the hotter surface, and Tc is temperature of the cooler surface, all temperatures in degrees absolute.  In this formula, ^n indicates raising the preceding variable to a power, where Th^4 is the Th raised to the fourth power.   It is crucial to note that the energy E is the NET radiated energy between the two surfaces.   Each surface radiates at a rate governed by its own surface temperature.   Therefore, where two surfaces are at the same temperature, ZERO energy is radiated away on a net basis. )

It can be seen, then, that cities have a built-in heating system, if only from the buildings that cannot easily radiate away their heat.   Yet there are many other aspects of city heat, as described above.  The concentration of vehicles that burn fuel and emit heat via the exhaust, the cooling system, and hot engine also raises the air temperature in a city.   

Every electric motor in a city also produces heat that must be dissipated.  Every air conditioning system also sends heat into the air.  

Now to the key point: cities will have energy consumption and heat rejection issues no matter what type of system produces that energy.  Considering for the moment electricity use, even if a city were all-electric for heating, cooking, and transportation, and even if that electricity were produced by zero-carbon-dioxide power plants (see below), the UHI would exist.  In essence, a building has no idea what produced the electricity that heats the building, runs the lights and elevators, and heats the hot water.  An electric car, or bus, or delivery truck, or train, also has no idea what produced the electricity that each of those consumes.   Therefore, even if all the electricity is from a zero-carbon-dioxide source, the cities would still have UHI and would corrupt the climate scientists' data.   Such zero-carbon-dioxide sources include, but are not limited to, hydroelectric, wind, solar, nuclear, geothermal, wave, tidal, ocean current, ocean temperature-difference, water pressure recapture, river mouth osmosis, and river current.   There are also carbon-neutral sources: landfill methane, cattle operation methane, Municipal solid waste (MSW), human waste sludge, plant-based ethanol, other bio-fuels,   

It is entirely wrong for climate scientists to include any data that is corrupted by UHI.  

For completeness, the impact of solar energy on the city is described.  Up to this point, only the addition of non-solar energy to a city has been discussed.  Sunshine, or solar energy, is absorbed by the city buildings, streets, and other areas.  This heat must also be dissipated, and has the same dissipation options as described above: conduction, convection, and radiation.  Once the solar energy is absorbed, a building has no idea what caused the increased heat.  Therefore, any energy also has the same issues as non-solar energy.  


Most of the world's nations will soon convene in Paris, France, to discuss climate change and try to agree on a mechanism and by how much each nation will reduce emissions of carbon dioxide, in the belief that doing so will stop the Earth from warming.   It is clear, however, that the climate or land temperature database is corrupted by including UHI.   It is essential that the delegates, and policy-makers, understand that there is no man-made global warming due to CO2 emissions.    It is scientific error to include in their database the hot cities and other locations where warming is indeed occurring, but would occur no matter what is the source of the energy.  

The Goodridge paper shows that zero warming occurred in more than 80 years in counties with small populations, while substantial warming occurred in counties with more than 1 million population.   Furthermore, recent data from the USCRN, for pristine sites throughout the USA, shows not only zero warming, but a pronounced cooling.  (see link)

For additional reading on UHI, the IPCC report AR5 has quite a bit to say:
(click here for link)  (Note, this link is to a 113 page pdf that does not automatically download)

More charts and references will be added to support the arguments above. 

Below are shown the temperature records of three large US cities: Boston, New York City, and San Francisco.  The warming rates, in degrees C per century, are 1.99, 1.49, and 1.49 respectively.   These warming rates are in line with what Goodridge reported for the largest counties in California for the 85-year period 1904 to 1996, approximately 1.7 degrees C per century. 

For reference, Boston urban area had 4.1 million people in 2010, with a density of 13,000 people per square mile.

New York City urban area had 8.5 million people in 2010 and a density of 27,000 people per square mile. 

San Francisco had 4.6 million people in 2010 and a density of 18,000 people per square mile. 

In contrast, the small cities shown below, Sacramento, California, and Abilene, Texas had populations and densities as follows.  

Sacramento had 460,000 people in 2010 with a density of 4,700 people per square mile. 

Abilene had 115,000 people in 2010 with a density of 1,100 people per square mile. 

Here are two smaller cities, Sacramento, California, and Abilene, Texas. These show zero warming, instead, a slight cooling of minus 0.29 and minus 0.19 degrees C per century, respectively.  

Additional temperature trend graphs similar to those shown above may be examined at this link, where results of 87 cities from 42 states in the USA are posted.   The data are from Hadley Climatic Research Center's hadCRUT3 files that were voluntarily released onto the internet, in late 2009, following the Climategate scandal. 

Links to previous SLB articles on Global Warming:
Warmists are Wrong, Cooling is Coming   (2012)

From Man-made Global Warmist to Skeptic - My Journey   (2011)

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

No comments: