The analysis of minimum temperature data using the PDO as a reference baseline has been demonstrated as a powerful technique for climate trend evaluation.
This technique may be extended to other regions using the appropriate local ocean surface temperature reference. The analysis found no evidence for CO2 induced warming trends in the California data. This confirms prior ‘Null Hypothesis’ work that it is impossible for a 100 ppm increase in atmospheric CO2 concentration to cause any climate change.
The weather is always changing on a daily basis and climate is often evaluated using long term averages of daily maximum and minimum temperatures and precipitation. This is the weather station record that is available from about 1880 onwards. However, the meteorological surface air temperatures (MSAT) are recorded by a thermometer located in an enclosure placed at eye level, 1.5 to 2 m above the ground. The surface or ‘skin’ temperature is the temperature of the ground itself below the thermometer. This is set by the dynamic energy balance at the surface between the short wave (solar) flux, the long wave infra red (LWIR) flux, surface evaporation and convection. It also includes subsurface heating and cooling. The incoming solar flux can reach 1000 W.m-2 and the night time LWIR cooling flux can easily vary between 0 and 100 W.m-2, depending on cloud cover and humidity.
The increase in downward atmospheric LWIR flux from the observed 100 ppm increase in CO2 concentration over the last 200 years is 1.7 W.m-2 under ideal ‘clear sky’ conditions. When this CO2 flux is added to the daily flux balance with fluctuations that can exceed 1100 W.m-2, it becomes clear that there can be no CO2 ‘signature’ in the MSAT record.
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