<title>Remote sensing of atmospheric pollution by passive FTIR spectrometry</title>

Abstract

Passive remote sensing with a Fourier transform infrared (FTIR) spectrometer allows the detection and identification of pollutant clouds in the atmosphere. In this work, the measurement technique and a data analysis method that does not require a previously measured background spectrum are described. Recent experimental results obtained with a new high sensitive FTIR remote sensor are presented.Many situations do not allow the measurement of a background spectrum prior to the measurement of pollutants in order to perform background removal. After a radiometric calibration of the FTIR spectrometer with IR reference sources the spectral radiance of the environment can be measured. With the inverse function of Planck's radiation law, the (spectrally resolved) brightness temperature is computed. The temperature spectrum has a constant baseline for many natural materials that serve as the background in field measurements (forest etc.) because their emittance ε(ν) is high and almost constant in the spectral range 800-1200 cm -1. The influence of environmental and instrumental parameters on the sensitivity of the method is discussed. Experimental results are presented to illustrate the enhancement of the signal to noise ratio that can be achieved by the alignment of the spectrometer to backgrounds with a high temperature difference to the environment.

Detection of Gaseous Plumes in IR Hyperspectral Images—Performance Analysis

“…Neglecting atmospheric transmission effects and after linearization of Plank's black body radiation with respect to the temperature (which can be justified for small temperature differences), we can extract the gas transmission in each wavelength by (other methods to derive similar expression are described in [3], [7]). …”

“…The formulation of the obtained radiance with the presence of a gaseous plume in the instantaneous field of view (FOV) of an IR sensor has been extensively studied in the past [1]- [4], [7], and it was reviewed briefly in our previous work [5]. Neglecting atmospheric transmission effects and after linearization of Plank's black body radiation with respect to the temperature (which can be justified for small temperature differences), we can extract the gas transmission in each wavelength by (other methods to derive similar expression are described in [3], [7]).…”

Estimation of air pollution using remote sensing technique in coimbatore-a case study

“…Some common air pollution assessment technique are there for detecting air pollution, of which remote sensing method is used in wide area because for its global coverage. Fourier transform IR spectrum a payload in a satellite was the instrument used to analyze pollutant clouds in the atmosphere by passive remote sensing method [12]. Using thermal remote sensing, heating up of environment due to air pollution was detected.…”

Technique for passive scene imaging of gas and vapor plumes using transmission-waveband modulation

“…2 Video technology has been used for imaging anthropogenic gas distributions 3,4 such as NO 2 and SO 2 . Typically this has been achieved using Fourier transform infrared (FTIR) spectroscopy techniques, 5 which are scanning rather than direct-imaging techniques.…”