Characterization of a fourier transform spectrometer for the network for detection of stratospheric change

The Network for Detection of Stratospheric Change is a set of high quality ground based observing stations, which, combined with satellite observations, is intended to provide the earliest possible warning of changes in the chemistry and dynamics of the stratosphere as well as data to understand the causes of the change. There will be five primary stations, some distributed among several sites, and numerous complementary sites. Each primary station will have the same complement of instruments, including UV/visible, infrared, and microwave spectrometers, lidars for temperature, aerosol, and ozone measurements, ozonesondes, and instruments for measuring UV-B irradiance. Each primary station and many complementary sites will have a high resolution FTIR spectrometer observing atmospheric absorption using the sun, and possibly the moon, as a source. Important characteristics of the FTIR spectrometers include the spectral resolution and detailed instrument line shape, the observation time, and the signal to noise ratio in the spectra. The expected performance of these instruments is described, as well as methods for testing the actual performance. In addition to determining with high precision the total column amount of various trace gases, we will attempt to derive some information on the vertical profile of some gases from the resolved line shape. For this purpose, precise knowledge of the instrument line shape is crucial. We will describe the validation of the line shape measured with the Bruker spectrometer.