Stratosphere temperature profile

Radiative forcing defined as a change in the energy flux at the tropopause is referred to as instantaneous forcing (Figure 23.10a). The adjusted radiative forcing, which is the measure now commonly used, is the radiative forcing at the top of the atmosphere (TOA) in which the stratospheric temperature profile is allowed to adjust to the perturbation and... 

This process does not lead to net ozone depletion because it is rapidly followed by reaction 2, which regenerates the ozone. Reactions 2 and 3 have, however, another important function, namely the absorption of solar energy as a result, the temperature increases with altitude, and this inverted temperature profile gives rise to the stratosphere (see Figure 1). In the lower layer, the troposphere, the temperature decreases with altitude and vertical mixing occurs on a relatively short time scale. In contrast, the stratosphere is very stable towards vertical mixing because of its inverted temperature profile. 

However, at the tropopause the temperature profile changes, increasing with altitude throughout the stratosphere. The reason for this increase is a critical series of photochemical reactions involving ozone and molecular oxygen. The Chapman cycle, reactions (l)-(4), hypothesized in the 1930 s by Sir Sydney Chapman,... 

As discussed earlier, although C02 warms the troposphere, it cools the stratosphere since it efficiently radiates infrared out to space. This effect can contribute to changes in the temperature profile in the stratosphere and potentially have a signficant impact... 

Fig. VIII—1-4. Proposed temperature profile of Jupiter s Atmosphere. The tropo-pause is chosen as height reference since there is no evidence of a solid surface. The temperature at the tropopause is 9S.5°K and the number density is 2 x I01 cm 3. Contrary to the case of the upper atmosphere of earth, there appears to be no boundary between stratosphere and mesosphere. The observed cloud deck is believed to be solid ammonia. (M) signifies the number of molecules per cm3. From Hunten (490b), reprinted by permission of the American Meteorological Society. 

The vertical temperature profile of the earth s atmosphere conveniently allows it to be described as comprised of a number of vertical layers. From the earth s surface upward, these are the troposphere, stratosphere, mesosphere, and thermosphere (Mcllveen, 1992). Because 85% of the mass of the atmosphere resides in the troposphere, and most... 

I would like to congratulate Dr. Crutzen on one of the most impressive papers that I have heard in the last 43 years. With regard to its policy implications, it stands certainly in a class all by itself. I would simply underscore Dr. Crutzen s emphasis on the conservativeness of his estimates. Having looked at thousands of vertical temperature profiles, it is clear, I believe, that the residence time will be of about an order of magnitude difference between the stratosphere rather than the troposphere, and also the lapse rates, would no longer apply. So as you say, it is just an entirely different atmosphere. This would inhibit the precipitation and the fallout, so that I just really wanted to underscore the conservative nature of your calculations. 

Another major feature of the vertical thermal structure of the atmosphere is due to the presence of ozone (O3) in the stratosphere. This layer is caused by photochemical reactions involving oxygen. The absorption of solar UV radiation by O3 causes the temperature in the stratosphere and mesosphere to be much higher than expected from an extension of the adiabatic temperature profile in the troposphere (see Fig. 10-1). 

The surface separating the troposphere from the stratosphere is called the tropopause. It is associated with the minimum in the vertical temperature profile observed near 7-16 km altitude. The World Meteorological Organization (WMO) defines the tropopause level as the lower boundary of a layer in which the vertical decrease in temperature is less than 2 K/km for a depth of at least 2 km. 

It needs to be emphasized that the vertical temperature profile varies depending on the geographic latitude and solar activity. For example, the tropopause is essentially higher and it has lower temperatures above tropical areas as compared to those above the polar regions. In the lowest layers of the stratosphere, the temperature profile depends on the geographic situ-... 

Example 5.3 The Troposphere/Stratosphere Transition The transition from troposphere to stratosphere is traditionally defined based on the reversal of the atmospheric temperature profile. That transition is also dramatically reflected in how the concentrations of trace species vary with altitude below and above the tropopause. Of trace species, HO2 and OH exhibit perhaps the most profound differences across the tropopause (Wennberg et al., 1995). In the lower stratosphere HO2 and OH participate in HO Cycle 4, which is the predominant cycle involved in O3 removal in that portion of the stratosphere. We saw in Chapter 4 that in the lower stratosphere the HO2/OH ratio is described by... 

Stratospheric O3 provides protection against UV-B radiation (wavelength range 1 = 280—320 nm) and it determines the temperature profile in the stratosphere by absorbing solar UV radiation. In the latter context, O3 is an important species that can affect climate warming/cooling trends (e.g. Roelofs et ai, 1997). In the troposphere, however, O3 is perceived as more of a pollutant, which has adverse effects on animals and plant life, especially above background levels of about 40 ppb. 

Fig. 30. Temperature profile of the atmosphere and stratosphere derived from Nimbus 4 and radiosonde data on 10 April 1970. Nimbus 4, selective radiometer. Communicated by the inventor of the instrument, Jim Williamson, Oxford University, England.

The CO2 channel has been the source of considerable progress from this channel we have been able to find out daily, throughout the world, the distributions of and changes in stratospheric temperatures. With Nimbus 4, an additional step has been taken for the first time we are continuously deriving temperature profiles from ground level to an altitude of 50-60 km. Figure 30 shows the first result obtained two days after the satellite was launched. 

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