Water+Buffaloes

 ** The Claim: **  **If global warming is really increasing, then the temperature in the middle of the troposphere should be increasing, but satellite data shows these temperatures are decreasing. The //supposed// warming measured at ground level is the result of faulty data.** **__DISPELLING THE MYTH__**
 * < ** __ TABLE OF CONTENTS __ ** ||
 * < **Part I: Does satellite data show a decrease in tropospheric temperature?** ||
 * < i. Radiosondes ||
 * < ii. Microwave Sounding Units ||
 * < iii. Incorrect Interpretations of Satellite Data ||
 * < iv. Mt. Pinatubo ||
 * < **Part II: Are the measurements from ground level the result of faulty data?** ||
 * < i.Multiple Lines of evidence ||
 * < **Conclusion** ||
 * < **Sources** ||

 **__ Part I __: Does satellite data show a decrease in tropospheric temperature?**

__ **Radiosondes** __ **:** Radiosondes are balloon-like instruments which measure the temperature of the troposphere. Over the last 40 years, radiosonde measurements have been taken twice daily, one each during the day and the night. Nighttime measurements have been in agreement with climate models; however daytime measurements have shown a cooling in the temperature since the 1970's. This apparent cooling can be accounted for by looking at older radiosonde instruments which were not insulated against sunlight. Since the instruments were not protected from the sun's heat, the temperatures they measured were higher. Now, the radiosondes are insulated, which has resulted in temperatures that are cooler than they originally were, making it look like the troposphere is cooling. However, recent measurements agree with climate models which predicted the warming of the atmosphere. This confirms the idea that the troposphere is in fact warming.

Radiosondes are balloon-like instruments which measure the temperature of the troposphere. Over the last 40 years, radiosonde measurements have been taken twice daily, one each during the day and the night. Nighttime measurements have been in agreement with climate models; however daytime measurements have shown a cooling in the temperature since the 1970's[7]. This apparent cooling can be accounted for by looking at older radiosonde instruments which were not insulated against sunlight. Since the instruments were not protected from the sun's heat, the temperatures they measured were higher. Now, the radiosondes are insulated, which has resulted in temperatures that are cooler than they originally were, making it look like the troposphere is cooling[[|6]]. However, recent measurements agree with climate models which predicted the warming of the atmosphere. This confirms the idea that the troposphere is in fact warming[7].

 lkudshqowiherwaeuioreuirwerwerwerwadfaerwerw media type="youtube" key="dCyWWtdErBw" height="344" width="425" __**Microwave Sounding Units (MSUs):**__

MSUs collect data from microwave wavelengths and use them to determine temperatures of different levels of the atmosphere. 10-15% of MSU data comes from the stratosphere, the rest coming from the troposphere[[|4]]. Since the stratosphere is cooling more rapidly than the troposphere is warming, the warming is cancelled, and the data which concludes that the troposphere is cooling is faulty[7].

__**Incorrect Interpretations of Satellite Data:**__

The original claim that the troposphere was cooling and therefore climate models that predicted atmospheric warming were incorrect was released by a group of researchers led by John Christy and David Douglass. These scientists failed, however, on many accounts to accuratly interpret the satellite data. Although they knew that the satellites drift and this movement can create disturbances in the data, Christy and Douglass incorrectly calculated the correction for the movement[[|4]]. The correction is referred to as diurnal correction, and was later recalculated by Carl Wears and Frank Wentz. As the satellites travel across the Earth from pole to pole, they sink through the atmosphere and slowly fall off their time tracks. The LECT, or local equator crossing time, corresponds to the time at which the satellite is supposed to cross the equator, but can vary widely due to satellite drift. Slow changes in the time at which the satellite crosses the equator causes long term mistakes and need to be corrected[[|4]]. Christy et al. calculated the effect of the diurnal cycle by taking the average rate of warming and cooling and subrtacting the temperatures from one side of the measurem ent swath to the other. Mears and Wentz, on the other hand, used data from over five years and used a radation model to calculate the seasonal diurnal variations[[|4]]. Mears and Wentz recorded an opposite sign for many of their measurements. The figure below shows a comparison between Mears' and Christy's data (Christy's is on top and Mears' on the bottom). Where Christy's showed decreasing trend of up to .15K per decade, Mear's data shows an equal increase[[|1]].

Mears and Wentz calculated a global warming trend of .193K per decade, which is about .1K higher than Christy et al., and a warming trend of .189K per decade in the tropics, .2K higher than Christy[[|4]]. It is estimated that diurnal corrections acount for 50% of differences in global warming trends between scientifci reports and 70% in tropic trends[[|4]]. Another critique of Douglass et al.'s research comes from a group of 12 scientists from differnt organizations that set about researching the discrepencies between surface and troposhperic temperatures. They looked closely at the previous publication by Douglass et al. that stated "models and observations disagree to a statistically significant effect." They found that the Douglass et al. report didn't take into consideration "climate noise" or the naturally present variations in temperature cause by natural events, such as La Ninas and El Ninos[[|5]]. The Douglass et al. report based temperature changes on purely human influence. After accounting for this noise, the researchers applied the same methods as Douglass and found opposite results for the warming of the troposphere. The thick red and black lines show the average temperature trend for the tropospher and the surface. These trends show a greater warming of the troposphere, which is consistent with computer models. The bottom figure shows temperature changes associated with El Ninos and La Ninas. There is a strong correlation between tropospheric temperatures and El Ninos, an effect that Douglass et al. failed to account for[[|5]]. __**Mt. Pinatubo:**__

Researchers from Los Alamos National Laboratory discovered that a cooling troposphere and warming surface can coexist due to the eruption of Mount Pinatubo in 1991. The eruption sent large quantities of ash and aerosols into the atmosphere that depleted the ozone layer in the stratosphere and upper troposphere. Since the ozone layer absorbs UV radiation, it heats the upper atmosphere. When it is destroyed, it doesn't absorb as much of the sun's radiation, and the layers containing ozone loose heat. For the thirteen years before Mt. Pinatubo, there is a strong correlation between surface and atmospheric temperatures. During 1992 and 1993, however, the troposphere and stratosphere cooled dramatically. The atmosphere then began warming again at rates comparable to that of surface increases, but at a lower level[[|3]].

**__Part II__: Are the measurements from ground level the result of faulty data?**

__**Multiple lines of evidence:**__

The claim that the ground data that shows warming trends is faulty is incorrect. Multiple lines of evidence prove the validity of ground data, including agreement among many groups of independent researchers and organizations. This is further supported by evidence of rising sea levels, melting ice caps, thawing of permafrost, and changes in freeze and thaw dates[[|2]].


 * Conclusion **

Through our investigation into this claim, we found that the ground data is, in fact, reliable, and the tropospheric data has been misinterpreted by multiple groups of scientists. Newer analysis of the tropospheric data shows a closer relation to the expected warming of the atmosphere. The work of Douglass et al. and Christy et al, the original skeptics of tropospheric warming, had several shortcomings. They mistakenly calculated the diurnal correction and failed to account for natural temperature changes occurring from El Ninos and La Ninas. Improvements in radiosonde insulation gave the impression that the troposphere was cooling despite an actual warming trend. The satellite data used in many reports has been contaminated by signal from the stratosphere. The ground data is supported by many pieces of evidence and multiple interpretations of data, making it sounder than that collected from the atmosphere.  ** Sources **

1.Cook, John. "Satellites show little to no warming in the troposphere." 2009. 11 Mar. 2009.<[]>

2.Fu, Qiang, Celeste M. Johanson, Stephen G. Warren, and Dian J. Seidel. "Contribution of Stratospheric Cooling to Satellite-Inferred Tropospheric Temperature Trends." __Nature: International Weekly Journal of Science__ (2004): 55-58. 14 Mar. 2009 <[]>

3.Los Alamos National Laboratory. "A Cooling Troposphere and Global Warming Can Co-Exist." Press release. 2005. Los Alamos National Laboratory. 11 Mar. 2009 [].

4.Mears, Carl A., and Frank J. Wentz. "The Effect of Diurnal Correction on Satellite-Derived Lower Tropospheric Temperature." __Science__ (2005). 14 Mar. 2009 [].

5.Santer, B. D. "Fact Sheet for "Consistency of Modelled and Observed Temperature Trends in the Tropical Troposphere"" __International Journal Of Climatology__ (2008).<[]>

6.Than, Ker. "Key Claim Against Global Warming Evaporates." __MSNBC__ 11 Aug. 2005. 11 Mar. 2009 <[]>

7.Wolfson, Richard. __Energy, Environment and Climate__. New York: Norton & Co., 2008.