II. TECHNICAL CONSIDERATIONS
What is Temperature? Temperature is merely an index to indicate the heat content in a substance. Relative to life forms, they require boundaries or limits and controls within which they can survive. There has been more than one scale used in history to determine temperatures. These scales have graduated increments from absolute zero (no heat content) in increasing temperature to the freezing point of water, the boiling point of water, and continuing up in heat content. The conditions are specified in thermodynamic terms as STP conditions or “standard temperature and pressure”. I began study using English units of Fahrenheit and Rankine, and metric units of Centigrade and Kelvin. The academicians have long since replaced Centigrade with Celsius. A metric degree is about 9/5 of a Rankine degree. Water freezes at zero degrees Celsius, and boils at 100 degrees. In most cases today, the NASA (NOAA) measurements by satellite are in metric units. You get 100 degrees C under STP and a different value for pressures below and above one atmosphere of pressure.
You won’t get this from most sources. There are two measurement techniques for obtaining temperatures. The first is direct measurement by thermometry or thermocouples (bimetallic strips). With calibration based on the current scales, these are said to give temperature measurement accuracy to within hundredths or thousandths of a degree of the environment in which they are placed, whether solid, liquid, or gas. There is a problem. Calibration of the environment must account for heat transfer. Those gages in the bank marquees probably do not calibrate for sunlight coming through the enclosed glass structure. Thus, they are measuring “an environment”, but not the outside air temperature. The second technique mostly used by NASA is by radiometry. All indirect measurements by a radiometer require some type of analytic solution to convert to temperatures from the amount of radiation received. There are various types of wide band radiometers and spectral line radiometers, and with information required to identify specific source(s) of the input. There are differences between earth surface, lower atmosphere, middle atmosphere, and upper atmosphere. Many problems have been encountered with calibrating specific types of detectors. Still, all in all, such results of indirect measurements are generally scientifically accepted as “accurate”. By accurate, they mean a fraction of a degree, but that is the best estimate. Radiometry could be used at ground level, too. That is not the problem. The problem with all earth measurements to define global warming is defining an average temperature and its history.
Average Earth Temperatures. There are at least two average temperatures, or averaging techniques. The first is by time, the second is by area. This presupposes that the scientist or measurement guy doesn’t just take random samples at various sites and times and uses them as he pleases. In the direct measurement method, a temperature over concrete at the airport on the same sunny day gives a different value than a suburbian field. Another issue is that there are insufficient measurements, earth-wide, to accurately average over area. Further, about 70% of the earth surface is water, without many measurements. With time averaging, different evaluators do a variety of averaging techniques. With daily cycles, seasonal cycles, storm cycles, and the effects of changing atmospheric turbulence in one form or another, the “time averages” should consider time-integrated averages (of all the cycles). I don’t think they do this. When you consider how to evaluate averages to include all areas, it becomes a monumental task with many inaccuracies. It is certain that direct earth measurements cannot be made by direct thermometry to give average temperatures to within a fraction of a degree, regardless of the analytic techniques of averaging.
This leaves indirect measurement techniques by radiometry from aircraft or satellite. There are not enough aircraft in the world to do any good. Who said there was? The satellite measurements are limited to a few satellites making continuous measurement scans in their continuous orbits, day in and day out. There are two orbits: geo-stationary and polar orbits in which they operate. At the present time, the United States operates 2 GOES (geostationary) satellites, (GOES-8 and GOES-10), with two in standby (orbiting, but not turned on, (GOES-9, and GOES-11)). The U.S. also operates 3 polar-orbiting satellites,(NOAA-14, NOAA-15, and NOAA-16) with one polar-orbiter in standby (NOAA-12). Other countries have some too. The results include both earth surface temperatures, and atmospheric temperatures. Questions of accuracy involve both analytic models and the portion of earth being measured (that is, portion of atmosphere or earth’s surface), and the methodology of averaging over area and time for trends. It is a huge problem, in spite of “scientific” claims to the contrary. Within the last two decades, there are many “scientific” outputs that do indicate the complexities of the atmosphere and the effects of water vapor (the primary radiator and absorber in the atmosphere), the uncertainties in other constituents such as carbon dioxide, particulates, hydrocarbons, and impact both short term and long term of convection within the atmosphere, along with solar radiation variations. As a thermodynamicist, to the chagrin of most other scientists, I tell you that there is no such thing as convection as a fundamental heat transfer mode. There is only conduction and radiation. That label (of convection) is used on an empirical basis, with fairly good analytic models actually in some cases, because we just don’t know, or cannot put together the conduction and radiation models to handle pipe or aerodynamic flows, much less atmospheric movements. It is empirical!
What produces these Temperatures? Some understanding of heat balances and variations of the sun-earth system is helpful to understand why there are uncertainties related to establishing average temperatures (and forecasting). Consider the solar-earth system. The data from my 1960 master’s thesis on solar radiation for satellite design (ancient history now) have not changed much. Earth in its slightly eccentric orbit around old Sol receives electromagnetic radiation in the nominal amount of about 2 cal/cm2/min. Most of this is in the visible and infrared wavelengths. (I am a wavelength guy, physicists often speak in terms of frequencies). The error estimate is about 2%. In addition, the orbital variation is about plus or minus 3.5%. In 1960 available data indicated periodic variations in the solar constant on the basis of 11-year cycles. It was estimated that the periodic variation was a few percent. It does not include effects of sunspots, particle bursts, cosmic radiation and other such things. In typical heat balance analyses, the solar reflections from the moon are neglected. This is reasonable with an estimated 0.07 lunar surface reflectivity multiplied by the configuration factor for radiative included angle (moon to earth). The heat balance is not between the sun and earth surface, but between the sun and the earth-atmosphere system, including earth rotation in the day-night cycle.
The single major issue is water vapor and clouds in this balance. Bipolar molecules such as H2O absorb and radiate. It varies over the surface of the earth from hour to hour and day to day. Any assumption for conditions inherently incorporate large errors that will be even larger tomorrow, maybe less the day after. As solar radiation hits the earth-atmosphere system, some is reflected, some scattered to space and earth, some absorbed, and some passes transparently through the atmosphere to the earth surface. All bodies radiate according to their temperature. The earth-atm system radiates at “low temperatures” in the infrared to itself and to space. Sometimes this is referred to as black body radiation because it occurs according to the Boltzmann equation. Now that is an approximation too, and we use a correction number called emissivity to denote departure from black body theory. “A kind of summary for sun and earth” from the thesis is as follows to illustrate the problems with solar radiation heat transfer (labeled as 100 units):
Incident Solar Radiation (100 units): Direct Solar to earth surface: 24
Atmosphere to space: 48
Diffuse Solar through clouds: 17
Atmospheric absorption: 19
Reflection (clouds & earth): 25
Scattering to space: 9
Earth radiation: Infrared to space: 18
Atm to space: 48
Atm IR to earth: 105
Earth IR to atm: 101
If all the solar radiation were absorbed by the earth system and radiated uniformly back to space at its equilibrium temperature, the mean over the earth surface would be about 82 deg Fahrenheit. A major fallacy in the global warming argument occurs in considering any heat balance. As the earth system warms, it radiates more to space, and the temperature drops accordingly.
Both earth surface characteristics AND spectral characteristics of ALL atmospheric constituents must be considered in any detailed analyses of determining the temperatures. Although the earth surface may be considered almost a black body, its emissivity (departure from black body theory) varies from land to sea, and from equator to the white capped poles. Now, a stupefying problem: ALL atmospheric constituents vary in the day-night cycle AND over the surface of the earth: from land to sea, and from pole to pole! There are not enough measurements available to cover all the details.
Other constituent measurements including aerosols, volcanic eruptions, maybe some sulphates, and beast of all beasts, methane from humans and animals are not available. There is an obvious solution: just do away with both!
Considering all the problems of data measurement and obtaining accurate values, we have omitted another huge problem: the analytics of atmospheric movement. The meteorological forecasts are based on local and worldwide measurements of temperature, pressure, velocity, densities, and humidity at local sites. There are not enough of these to be all inclusive with respect to forecasting “exact” conditions. After all, it is written, “The wind blows where it wishes and you hear the sound of it, but do not know where it comes from and where it is going.”
Labels: Global Warming