Detector Nonlinearity Correction Scheme for the LPMA Balloonborne Fourier Transform Spectrometer

Area of Science:

• Atmospheric science
• Spectroscopy
• Instrument calibration

Background:

• The Limb Profile Monitor of the Atmosphere (LPMA) is a Fourier transform spectrometer used for stratospheric and tropospheric absorption spectra analysis.
• The instrument utilizes photoconductive HgCdTe and photovoltaic InSb detectors, both cooled with liquid nitrogen.
• High photon fluxes during solar occultation cause nonlinearity in the HgCdTe detector's response, affecting spectral accuracy.

Purpose of the Study:

• To develop and present a processing scheme to correct for HgCdTe detector nonlinearity in LPMA spectra.
• To minimize out-of-optical-band spectral artifacts introduced by detector nonlinearity.
• To ensure the accuracy of stratospheric absorption spectra recorded during solar occultation.

Main Methods:

• Designed a data processing scheme focused on minimizing spectral artifacts outside the desired optical band.
• Applied the developed scheme to correct nonlinear responses in HgCdTe detector data.
• Validated the method using spectra obtained under various balloon flight conditions.

Main Results:

• The processing scheme effectively corrects for HgCdTe detector nonlinearity in LPMA spectra.
• Minimized spectral artifacts were observed, leading to more accurate absorption spectra.
• The method demonstrated reliable performance across different flight conditions and with multiple HgCdTe detectors.

Conclusions:

• The developed processing scheme successfully addresses HgCdTe detector nonlinearity in LPMA measurements.
• This advancement improves the quality and reliability of stratospheric and tropospheric absorption spectra.
• The corrected data are valuable for atmospheric composition studies and climate research.