Physics in The Atmospheric Chemistry Experiment Research Paper

Physics in The Atmospheric Chemistry Experiment - Research Paper Example This paper discusses the physics involved in the experiment and how it is used to understand the effect of changes in the atmospheric layers on the ozone layer over the Arctic pole. Various parameters like temperature, pressure, etc. have been measured by custom made apparatus like the interferometers, spectrometers, spectrophotometers, etc. Launch- ACE used two major instruments in the mission. While the first instrument was a Fourier Transform Spectrometer (FTS), the other instrument was a dual optical spectrometer (Bernath, na). It was launched by NASA on August 12, 2003 using a Pegasus XL rocket at 650km above the Earth. The satellite was launched at an angle of 740 and orbited the Earth to cover tropical, mid-latitude and the Polar regions. The satellite operated in the UV-Visible-NIR region of the spectrum with the ACE-FTS being used in the NIR region while the MAESTRO Spectrophotometer was being used over the UV-VIS-NIR region (ACE, 2009). FTS operated in the range of 2-13 microns with a high resolution of 0.02cm-1 and a vertical resolution of 4km to up to 150km. the MAESTRO spectrophotometer operated in the UV-VIS-NIR spectral region of 285-1030nm with a vertical resolution of 1-2 km. ... Apart from this information, the satellite was also used to provide vertical profile information for temperature, pressure and the various molecules and their mixing ratios present in the atmospheric layers (ACE, 2009). Constituents- The primary instruments in the satellite are the FTS and the MAESTRO. The ACE-FTS is a Michelson interferometer with two corner cubes for producing the path difference with an end mirror which increases the path difference. The interference fringes are produced with a diode laser operating at 1500nm which are further Fourier Transformed to give the spectra. It has two detectors operating below 100K. Two imagers, one a Visible imager and other a near-IR imager at 0.525 and 1.02 microns are used to study the atmospheric absorption of aerosols and the clouds in the region. These two wavelengths are used for study as they are free of any absorption by the molecules present in the two layers, particularly the stratosphere (Bernath, 2005, pp25-26). The altitude profile information is sun tracked by detectors with 256x256 pixel sensors and a field view of 30mrad and a signal-to-noise ratio of more than 1000. The MAESTRO uses two spectrographs in the two overlapping windows which are 280-550nm and 500-1030nm with a resolution of 2nm. It is noted that the use of two spectrographs enhances the stray-light performance and enables the simultaneous measurement of two spectral bands at a narrow resolution. It also consists of photodiode detectors and a concave grating with an entrance slit always held horizontal to the sunset and sunrise. It also has a vertical resolution of 1-2km and a signal-to-noise