• Spectroscopy and Spectral Analysis
  • Vol. 39, Issue 4, 1317 (2019)
ZHANG Shang-lu1、2、*, HUANG Yin-bo1, LU Xing-ji1、2, CAO Zhen-song1, DAI Cong-ming1, LIU Qiang1, GAO Xiao-ming1, RAO Rui-zhong1, and WANG Ying-jian1
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
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    DOI: 10.3964/j.issn.1000-0593(2019)04-1317-06 Cite this Article
    ZHANG Shang-lu, HUANG Yin-bo, LU Xing-ji, CAO Zhen-song, DAI Cong-ming, LIU Qiang, GAO Xiao-ming, RAO Rui-zhong, WANG Ying-jian. Retrieval of Atmospheric H2O Column Concentration Based on Mid-Infrared Inter-Band Cascade Laser Heterodyne Radiometer[J]. Spectroscopy and Spectral Analysis, 2019, 39(4): 1317 Copy Citation Text show less

    Abstract

    Water vapor is an important component of the atmosphere. It is also an important factor to balance the radiation budget of the atmosphere system, which has an important influence on weather and climate change. The commonly used equipment for measuring the concentration of water vapor column, such as Radiosonde, Lidar, Microwave Radiometer, Solar Photometer, DOAS instrument and Fourier Transform Infrared Spectrometer are difficult to meet the requirements of high-resolution and portable mobility. Based on a high-sensitivity and high-resolution spectral detection technology, related researches have been carried out around the detection of water vapor column concentration. The main achievements are as follows: (1) Based on the laser heterodyne spectroscopy technology, a set of high-resolution laser heterodyne solar spectrum measuring devices with a narrow-line broadband inter-cascade laser as the local oscillator and the sun tracker is estabished, with a spectral resolution of 0.002 cm-1. (2) The Langley-plot method is used to calibrate the high-resolution heterodyne solar spectrum measuring device. The field measurement is carried out at the Purple Mountain Observatory in Yunnan, and the direct measurement data of the 2 831~2 833 cm-1 band solar spectrum are obtained. The high-resolution total atmospheric spectral transmittance is also obtained. (3) The Line by Line Radiative Transfer Model (LBLRTM) is used to calculate the total atmospheric spectral transmittance, and the nonlinear least square fitting is carried out with the measured spectral transmittance. The inversion of water vapor column concentration is realized. The concentration of water vapor column is also observed by the Microwave Radiometer. The consistency between the inversion results and the measured resultsis is relatively good, where the minimum relative deviation is 16.59%, and the maximum relative deviation is 21.69%. (4) The error of the inversion results and the measured results is mainly caused by the error of the inversion algorithm and the measurement error of the device. Inversion algorithm errors include the calculation error of the radiative transfer model, the actual temperature measurement error, the methane concentration uncertainty into the error, the deviation of HDO abundance and the natural abundance. The device measurement error includes the calibration error of device, the wavelength calibration error, the noise influence, the error caused by the weak fluctuation of the background signal and the DC signal. (5) The 2 831~2 833 cm-1 band selected contains the absorption of water vapor and methane, and the concentration of methane column is also retrieved. With the initial column concentration of methane as the reference value, it is found that the numerical average of the concentration of the methane column after the inversion is 14.41% higher than the initial column concentration. The high-resolution laser heterodyne solar spectrum measurement device combined with its inversion algorithm is an effective integrated equipment for detecting the whole atmospheric transmittance and the concentration of water vapor and methane column. It has a wide application prospect in the detection of multi-component gas concentration.
    ZHANG Shang-lu, HUANG Yin-bo, LU Xing-ji, CAO Zhen-song, DAI Cong-ming, LIU Qiang, GAO Xiao-ming, RAO Rui-zhong, WANG Ying-jian. Retrieval of Atmospheric H2O Column Concentration Based on Mid-Infrared Inter-Band Cascade Laser Heterodyne Radiometer[J]. Spectroscopy and Spectral Analysis, 2019, 39(4): 1317
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