Comparison of Three High Resolution Real-Time Spectrometers for Microwave Ozone Profiling Instruments

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

Klemens Hocke¹  Eric Sauvageat¹  Axel Murk¹  Mikko Kotiranta²  Roland Albers²  Richard Gomez³  Gerald Nedoluha³ 

[1] Institute of Applied Physics and the Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland;Institute of Applied Physics, University of Bern, Bern, Switzerland;Remote Sensing Division, U.S. Naval Research Laboratory, Washington, DC, USA;

关键词: Atmospheric measurements;    digital real-time spectrometers;    microwave radiometry;    microwave spectroscopy;    ozone;    remote sensing;   

DOI  :  10.1109/JSTARS.2021.3114446

来源: DOAJ

【 摘 要 】

In this contribution, we present a comparison of three digital real-time spectrometers used in passive remote sensing of ozone and other trace gases in the middle atmosphere. During a period of six months, we connected the spectrometers to the same radiometric front-end to perform parallel observations of the ozone emission line at 110.836 GHz. This allowed us to better characterize a bias previously observed on the integrated spectra of the Acqiris AC240, a widely used digital spectrometer which has been used for more than a decade in many operational microwave radiometers. We investigated the bias under different atmospheric conditions and found that it is caused by multiple sources. Nonlinearities in the calibration are responsible for part of the bias, but a larger contribution stems from a second effect in the AC240. Although this error source is still partly unexplained, we found that a simple correction scheme simulating a spectral leakage can be applied to the integrated spectra of the AC240 and worked well on our range of observations. We also show that by applying our bias correction to the spectra, we can correct the bias in the ozone retrievals. There is still a need for further measurements to validate this approximate correction, but it could help to correct the numerous time series of ozone and other atmospheric constituents recorded by the AC240.

【 授权许可】

Unknown