High altitude aircraft

Bennett G Ozone contamination of high altitude aircraft cabins. Aerospace Med 33 969-973, 1962... 

Johnston, H. S D. E. Kinnison, and D. J. Wuebbles, Nitrogen Oxides from High-Altitude Aircraft An Update of Potential Effects on Ozone, J. Geophys. Res., 94, 16351-16363 (1989). 

Proffitt, M. H J. J. Margitan, K. K. Kelly, M. Loewenstein, J. R. Podolske, and K. R. Chan, Ozone Loss in the Arctic Polar Vortex Inferred from High-Altitude Aircraft Measurements, Nature, 347, 31-36 (1990). 

The (0, 0) bands at A = 7620 A and A = 1.27 [x of the two atmospheric band systems may be observed from elevated altitudes, and balloon, high-altitude aircraft, and rocket experiments have been used to investigate the... 

Figure 1. This graph shows the rapid variation of CIO and 03 as the edge of the chemically perturbed region in the Antarctic polar vortex is penetrated by the National Aeronautics and Space Administration (NASA) ER-2 high-altitude aircraft over the Palmer Peninsula of Antarctica on September 16, 1987 (5). It is one of a series of 12 snapshots, or individual flights, during the Airborne Antarctic Ozone Experiment (AAOE) that show the development of an anticorrelation between CIO and 03 that began as a correlation in mid-August. When these two measurements are combined with all the others from the ER-2 aircraft, the total data set provides a provocative picture of how such chemistry occurs and what it is capable of doing to ozone.

Figure 2. The temperature and pressure distribution of the stratosphere. The solid line is from reference 7, and the dashed lines are from measurements made by the Meteorological Measurement System (MMS) instrument on the NASA ER-2 high-altitude aircraft during the AAOE mission in 1987 (8) and the AASE mission in 1989 (9). The Arctic was colder in 1989 than usual.

A large number of observations, both remote and in situ, confirm this qualitative picture of the loss of ozone over Antarctica. The in situ data have come from instruments carried on small balloons and the NASA ER-2 high-altitude aircraft. Small-balloon measurements are of particle distributions and sizes, ozone, and water vapor (23, 33). ER-2 measurements, listed in Table I, are of particle size and composition atmospheric parameters such as temperature, pressure, lapse rate, and winds and trace gas abundances of 03, N20, NOy or NO, CIO and BrO, and stable gases, including CH4, chlorofluorocarbons, halons, and others (34-45). 

Of all the trace gases, particularly the reactive trace gases, some of the most difficult to measure are the trace free radicals. At present, NO, CIO, and BrO have been measured from the NASA ER-2 high-altitude aircraft. The challenges of measuring NO (44, 79) from the ER-2 are similar to those of measuring from balloons, as discussed earlier in this chapter and in Chapter 9. Those discussions are not repeated here, but some examples of NO measurements are given. Instead, the measurement of CIO and BrO from the aircraft platform is discussed. 

The solar constant (intensity of solar radiation outside the Earth s atmosphere at die mean distance between die earth and the sun) has been determined by measurements from satellites and high-altitude aircraft and is 1.353 kilowatts per square meter. This extraterrestrial radiation,... 

Particle sampling devices have been flown on balloons (Hofmann and Rosen, 1983) and on high-altitude aircraft (Oberbeck et d., 1983 Knollen-berg and Huffman, 1983 Wilson et d., 1983 Gooding et d., 1983 Woods and Chuan, 1983). 

Stratospheric sulfate and other gases were collected by high altitude aircraft and balloons (Gandrud et d., 1983 Mroz et d., 1983 Vedder et d., 1983). These measurements indicated an injection of about 7.6 Tg of sulfate into the global stratosphere. Ground and airborne extinction measurements were also carried out (Clarke et d., 1983 Coulson, 1983 Dutton and De Luisi, 1983 Spinhirne, 1983 Witteborn et d., 1983) as well as comparisons with Lidar measurements (Swissler et d., 1983). Other reports on the initial phases of this phenomenon and attempts at drawing preliminary conclusions have by now appeared some will be mentioned in the following section. 

Hidalgo H. and Crutzen P. J., The tropospheric and stratospheric composition perturbed by NO emissions of high altitude aircraft. J. Geophys. Res. , 82, 5833-58 (1977). 

Many of the physical characteristics of the atmosphere, such as wind, temperature, cloud cover, humidity, and precipitation, are easily perceived. Sometimes, chemicals in the atmosphere also can be observed, as in smoke plumes and smog, and their physical transport tracked downwind just as downstream transport of substances in a river can be measured. Other atmospheric processes are less apparent to the unaided observer, however, occurring either on the microscopic scale of a chemical reaction, or on a global scale, or at high altitudes. Such processes may be detected only by instrumentation on satellites or some high-altitude aircraft. 

Figure 3.18. Observed mixing ratio of several chemical compounds (O3, NOy, SF6, CH4, CFC-12, HC1) represented as a function of the observed mixing ratio of N2O. These scatterplots are established with measurements made from the ER-2 high altitude aircraft and during the spaceborne ATMOS experiment. From Chang et al. (1996a, 1996b).

The earliest observations of the chemical composition of the middle atmosphere were performed primarily by balloon-borne (stratosphere) and rocket-borne (mesosphere) instrumentation. In recent decades, however, systematic observations have been made by space-borne sensors, and information on chemical processes in the upper troposphere and lower stratosphere has been provided through chemical measurements made from aircraft platforms (e.g., from high-altitude aircraft such as the ER-2, the WB-57 and the Geofysika). Measurements from ground stations, combined with satellite observations, have provided accurate estimates of long-term ozone trends in the different regions of the world. 

Figure 5.45. Correlations of NOy with N2O concentrations measured from ATMOS aboard the Space Shuttle and instruments aboard the ER-2 high altitude aircraft. Adapted from Chang et al. (1996).

Figure 6.8. Calculated one-dimensional model ozone column change resulting from specific fixed perturbations (increased NOx emissions at 20 km, simulating possible high altitude aircraft releases, and the steady-state response to 1974 emissions of chlorofluorocarbons), as function of the year in which the calculation was performed. Changes over time reflect changes in the understanding of stratospheric chemistry, not real atmospheric changes. Figure courtesy of D.J. Wuebbles (personal communication).

Over the past 15 years, the atmospheric science community has developed a series of mobile platforms with highly accurate and specific fast response instrumentation that have revolutionized atmospheric chemistry field measurements. These include high-altitude aircraft, such as NASA s ER-2 and WB-57, and lower-altitude aircraft like the NASA DC-8, the National Oceanic and Atmospheric Administration (NOAA) and Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) (Naval Postgraduate School) Twin Otters, the National Center for Atmospheric Research (NCAR) C-130, and the DOE Gl. In addition, mobile surface laboratories are now being used for a wide variety of urban and regional air quality and emission source characterization studies.4 Typical configurations for the ER-2 and the mobile laboratory are shown in Figures 1 and 2. 

FIGURE 1 View of NASA WER-2 High Altitude Aircraft With Stratospheric Chemistry Instrument Package. 

Some perchlorates have other, more limited, uses. For example, potassium perchlorate was previously used to treat Graves disease, a condition in which the body produces too much thyroid hormone. It is still used to monitor the production of thyroid hormones. Potassium perchlorate is also used in emergency breathing equipment for high altitude aircraft and underwater boats. Other uses of perchlorates include ... 

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