Improvement of Liquid Water Content Retrieval Accuracy by Multilevel Detection in Cloud Tomography

Jun Zhou Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

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Hengchi Lei Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

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Lei Ji Beijing Weather Modification Office, Beijing, China

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Abstract

A new multilevel detection scheme for cloud tomography is developed. This scheme solves problems intrinsic to conventional single-level detection, such as the lateral boundary problem and the low accuracy of liquid water content (LWC) retrieval for clouds without distinct liquid water cores. Sensitivity studies show that the new multilevel detection scheme can significantly enhance the well posedness of the inverse problem and increases the accuracy of the retrieval. These improvements are achieved not only for clouds with distinct liquid water cores but also for clouds with weak or no liquid water cores, which are difficult to accurately reconstruct using a single-level detection scheme. The settlement of the lateral boundary problem also leads to a natural and easy way of solving the detection time limit problem in cloud tomography. By using a multi-aircraft flight (MAF) scheme, segmental retrieval can be applied to make the applicable scope of cloud tomography much broader. Considering the detection time limit and the cost in practice, the feasible flight scheme at present is MAF with two detection levels. Although only one detection level is added to the conventional single-level scheme, the accuracy of LWC retrieval can be improved by 1.4%–13.1%.

Corresponding author address: Dr. Jun Zhou, Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. E-mail: zhoujun@mail.iap.ac.cn

Abstract

A new multilevel detection scheme for cloud tomography is developed. This scheme solves problems intrinsic to conventional single-level detection, such as the lateral boundary problem and the low accuracy of liquid water content (LWC) retrieval for clouds without distinct liquid water cores. Sensitivity studies show that the new multilevel detection scheme can significantly enhance the well posedness of the inverse problem and increases the accuracy of the retrieval. These improvements are achieved not only for clouds with distinct liquid water cores but also for clouds with weak or no liquid water cores, which are difficult to accurately reconstruct using a single-level detection scheme. The settlement of the lateral boundary problem also leads to a natural and easy way of solving the detection time limit problem in cloud tomography. By using a multi-aircraft flight (MAF) scheme, segmental retrieval can be applied to make the applicable scope of cloud tomography much broader. Considering the detection time limit and the cost in practice, the feasible flight scheme at present is MAF with two detection levels. Although only one detection level is added to the conventional single-level scheme, the accuracy of LWC retrieval can be improved by 1.4%–13.1%.

Corresponding author address: Dr. Jun Zhou, Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. E-mail: zhoujun@mail.iap.ac.cn
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  • Bobylev, L. P., 1997: Retrieval of liquid water distribution in convective clouds using microwave computerized tomography. IEEE Trans. Geosci. Remote Sens., 2, 830832.

    • Search Google Scholar
    • Export Citation
  • Drake, J. F., and Warner J. , 1988: A theoretical study of the accuracy of tomographic retrieval of cloud liquid with an airborne radiometer. J. Atmos. Oceanic Technol., 5, 844857.

    • Search Google Scholar
    • Export Citation
  • Hansen, P. C., 1997: Setting the stage, decompositions and other tools. Rank-Deficient and Discrete Ill-Posed Problems: Numerical Aspects of Linear Inversion, J. E. Flaherty, Ed., SIAM, 1–43.

  • Huang, D., Liu Y. , and Wiscombe W. , 2008a: Cloud tomography: Role of constraints and a new algorithm. J. Geophys. Res., 113, D23203, doi:10.1029/2008JD009952.

    • Search Google Scholar
    • Export Citation
  • Huang, D., Liu Y. , and Wiscombe W. , 2008b: Determination of cloud liquid water distribution using 3D cloud tomography. J. Geophys. Res., 113, D13201, doi:10.1029/2007JD009133.

    • Search Google Scholar
    • Export Citation
  • Huang, D., Gasiewski A. J. , and Wiscombe W. , 2010a: Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform—Part 1: Field trial results from the Wakasa Bay experiment. Atmos. Chem. Phys., 10, 66856697.

    • Search Google Scholar
    • Export Citation
  • Huang, D., Gasiewski A. J. , and Wiscombe W. , 2010b: Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform—Part 2: Observation system simulation experiments. Atmos. Chem. Phys., 10, 66996709.

    • Search Google Scholar
    • Export Citation
  • Jiang, F., Wei C. , Lei H. C. , Jin D. Z. , Zhang J. H. , and Gu S. F. , 2004: Measurement of column cloud liquid water content by airborne upward-looking microwave radiometer (II): Retrieval method (in Chinese). Plateau Meteor., 23, 3339.

    • Search Google Scholar
    • Export Citation
  • Jin, D. Z., and Coauthors, 2004: Measurement of column cloud liquid water content by airborne upward-looking microwave radiometer (in Chinese). Acta Meteor. Sin., 62, 868874.

    • Search Google Scholar
    • Export Citation
  • Koldaev, A. V., Melnichuk Y. V. , Mironov A. F. , Agapov Y. V. , Dmitriev V. V. , and Nikolski A. N. , 1990: The application of aircraft microwave radiometric tomography in weather modification experiments. Proc. 20th European Microwave Conf., Budapest, Hungary, IEEE, 1402–1407.

  • Lei, H. C., Wei C. , Shen Z. L. , Zhang X. Q. , Jin D. Z. , Gu S. F. , Li M. L. , and Zhang J. H. , 2003: Measurement of column cloud liquid water content by airborne upward-looking microwave radiometer (I): Instrument and its calibration (in Chinese). Plateau Meteor., 22, 551557.

    • Search Google Scholar
    • Export Citation
  • Liang, G., Lei H. C. , Li Y. , Yue Z. , Zhang X. Q. , and Gao B. , 2007: A column cloud liquid water content measured by airborne upward-looking microware radiometer (in Chinese). Plateau Meteor., 26, 11051111.

    • Search Google Scholar
    • Export Citation
  • Rodgers, C. D., 2000: Information aspects. Inverse Methods for Atmospheric Sounding: Theory and Practice, F. W. Taylor, Ed., World Scientific, 13–41.

  • Wang, Y., 2007: Numerical methods for linear inverse problems. Computational Methods for Inverse Problems and Their Applications (in Chinese), W. Guo, Ed., Higher Education Press, 33–84.

  • Wang, Z. E., and Coauthors, 2012: Single aircraft integration of remote sensing and in situ sampling for the study of cloud microphysics and dynamics. Bull. Amer. Meteor. Soc., 93, 653668.

    • Search Google Scholar
    • Export Citation
  • Warner, J., and Drake J. F. , 1984: Microwave tomography as a means of determing liquid water profiles in cloud. Proc. Ninth Int. Cloud Physics Conf., Talinn, USSR, ICCP–IAMAP, 823–826.

  • Warner, J., and Drake J. F. , 1985: Determination of cloud liquid water distribution by radiometric data. J. Atmos. Oceanic Technol., 2, 293303.

    • Search Google Scholar
    • Export Citation
  • Warner, J., and Drake J. F. , 1986: Liquid water distribution obtained from coplanar scanning radiometers. J. Atmos. Oceanic Technol., 3, 542546.

    • Search Google Scholar
    • Export Citation
  • Warner, J., and Drake J. F. , 1988: Field tests of an airborne remote sensing technique for measuring the distribution of liquid water in convective cloud. J. Atmos. Oceanic Technol., 5, 833843.

    • Search Google Scholar
    • Export Citation
  • Westwater, E. R., Crewell S. , and Matzler C. , 2004: A review of surface-based microwave and millimeter-wave radiometric remote sensing of the troposphere. Radio Sci. Bull., 3010, 5980.

    • Search Google Scholar
    • Export Citation
  • Zhou, J., Lei H. C. , Chen H. B. , Wang Y. F. , Zhao Z. , and Ji L. , 2010: Retrieval of cloud liquid water content distribution at vertical section for microwave radiometer using 2D tomography. Chin. J. Atmos. Sci., 34, 10111025.

    • Search Google Scholar
    • Export Citation
  • Zhu, C. Y., Byrd R. H. , Lu P. , and Nocedal J. , 1997: Algorithm 778: L-BFGS-B: Fortran subroutines for large-scale bound-constrained optimization. ACM Trans. Math. Software, 23, 550560.

    • Search Google Scholar
    • Export Citation
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