Zeng Zhengmao, Zheng Jiafeng, Yang Hui, et al. Quality control and evaluation on non-cloud echo of Ka-band cloud radar. J Appl Meteor Sci, 2021, 32(3): 347-357. DOI:  10.11898/1001-7313.20210307.
Citation: Zeng Zhengmao, Zheng Jiafeng, Yang Hui, et al. Quality control and evaluation on non-cloud echo of Ka-band cloud radar. J Appl Meteor Sci, 2021, 32(3): 347-357. DOI:  10.11898/1001-7313.20210307.

Quality Control and Evaluation on Non-cloud Echo of Ka-band Cloud Radar

DOI: 10.11898/1001-7313.20210307
  • Received Date: 2020-11-06
  • Rev Recd Date: 2021-01-18
  • Publish Date: 2021-05-31
  • Aiming at non-cloud echoes in Ka-band millimeter wave cloud radar observation, an improved data quality control method is proposed. Using the observation at Pinghe of Fujian from September 2018 to August 2020, the quality of the radar is quantitatively evaluated to study the actual impact of data quality control on cloud-precipitation detection. The non-cloud echoes show the characteristics of weak radar reflectivity factor (Z) and strong depolarization ratio (R) at Pinghe. But statistics show that there is difference from those of Qinghai-Tibet Plateau or Guangdong. Therefore, using the radar reflectivity factor (Z) less than -5 dBZ and linear depolarization ratio (R) greater than -22 dB as the judgment condition, and with the aid of filtering, non-cloud echoes can be effectively filtered. At the same time, a typical example is used to verify the effectiveness of the algorithm. Non-cloud echoes have a significant effect on the detection of cloud below 3 km, especially weak echoes. Non-cloud echoes account for 9.20% of all radar reflectivity factor samples, and 34.05% of all radar linear depolarization ratio samples. For the weak echo below -5 dBZ, the impact of non-cloud echoes is more significant, which accounts for 67.20% of all radar reflectivity factor sample. The detection rate of non-cloud echoes matter is closely related to the radar sensitivity, and the overall decrease with the height increaseing. The detection rate of non-cloud echoes decreases with the height increaseing. Meanwhile, non-cloud echoes have a certain relationship with the boundary layer, with an obvious diurnal change trend. From afternoon to midnight, due to strong turbulent activity, the detection rate of non-cloud echo matter is also higher, and the peak occurs at 1700 BT. From midnight to sunrise, due to the weakening of turbulent motion, the detection rate of non-cloud echo gradually decreases, and the lowest value occurs at 0400 BT. Non-cloud echoes have a significant effect on the vertical distribution of cloud precipitation. After quality control, the number of samples at the height of 0.12-2.5 km for radar reflectivity factor decrease by 17.68%, and the number of samples at the height of 0.12-4 km for radar linear depolarization ratio decrease by 14.29%.
  • Fig. 1  Probability distribution of measured Z and R of non-cloud and cloud-precipitation echoes observed by Pinghe radar in Fujian from Sep 2018 to Oct 2020

    Fig. 2  Frequency distributions of measured Z and R below 3 km altitude before and after quality control observed by Pinghe radar in Fujian from Sep 2018 to Aug 2020

    Fig. 3  Time-height frequency distributions of non-cloud echoes and frequency distribution of the whole levels observed by Pinghe radar in Fujian from Sep 2018 to Aug 2020

    Fig. 4  Frequency-height distributions of measured Z and R of non-cloud echoes before and after quality control observed by Pinghe radar in Fujian from Sep 2018 to Aug 2020

    Fig. 5  Comparison of low altitude cumulus cloud and deep convective precipitation cloud echoes before and after radar quality control observed by Pinghe radar in Fujian from 1200 BT to 2000 BT on 18 Apr 2019

    Fig. 6  Comparison of low altitude stratus clouds, cumulus and high altitude cirrocumulus echoes before and after quality control of observed by Pinghe radar in Fujian from 1700 BT to 2300 BT on 19 May 2019

    Fig. 7  Comparison of low altitude cumulus cloud and weak convective precipitation cloud echoes before and after quality control observed by Pinghe radar in Fujian from 1500 BT to 2300 BT on 2 Sep 2018

    Table  1  Major performance parameters for Ka-band millimeter wave cloud radar

    参数 数值
    工作频率 35 GHz±500 MHz
    波束宽度 0.4°
    脉冲重复频率 5988~16666 Hz
    峰值功率 20 W
    时间分辨率 1 min
    空间分辨率 30 m
    观测资料 Z/V/σV/R
    信号处理方式 FFT
    DownLoad: Download CSV

    Table  2  Major parameters of 4 detection modes

    参数 边界层模式 中云模式 高云模式 降水模式
    脉冲宽度/μs 0.2 8 24 0.2
    脉冲重复频率/Hz 16666 8333 5988 5988
    驻波时间/s 0.98 1.97 1.37 1.37
    相干积累数 4 2 1 1
    非相干积累数 16 32 32 32
    FFT点数 256 256 256 256
    距离分辨率/m 30 30 30 30
    有效探测高度/km 0.12~7.5 1.47~7.5 3.87~20 0.12~20
    最大不模糊速度/(m·s-1) 8.93 8.93 12.83 12.83
    速度分辨率/(cm·s-1) 6.98 6.98 10.02 10.02
    DownLoad: Download CSV
  • [1]
    Guo X L, Fu D H, Hu Z X. Progress in cloud physics precipitation and weather modification during 2008-2012. Chinese Journal of Atmospheric Sciences, 2013, 37(2): 351-363. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXK201302013.htm
    [2]
    Cheng Z J, Liu X X, Zhu Y P. A process of hydrometeor phase change with dual-polarimetric radar. J Appl Meteor Sci, 2009, 20(5): 594-601. doi:  10.3969/j.issn.1001-7313.2009.05.011
    [3]
    Guo X L, Fang C G, Lu G X, et al. Progress of weather modification technologies and applications in China from 2008 to 2018. J Appl Meteor Sci, 2019, 30(6): 641-650. doi:  10.11898/1001-7313.20190601
    [4]
    Shi L J, Xu X F, Li B, et al. Application of Doppler radar data to the landfalling Typhoon Saomai simulation. J Appl Meteor Sci, 2009, 20(3): 257-266. doi:  10.3969/j.issn.1001-7313.2009.03.001
    [5]
    Ge J X, Wang J, Wang J H, et al. Development and application of millimeter wave weather radar. Chinese Journal of Nanjing University of Aeronautics & Astronautics, 2018, 50(5): 577-585. https://www.cnki.com.cn/Article/CJFDTOTAL-NJHK201805001.htm
    [6]
    Kollias P, Miller M A, Luke E P, et al. The atmospheric radiation measurement program cloud profiling radars: Second-generation sampling strategies, processing, and cloud data products. J Atmos Oceanic Technol, 2007, 24: 1199-1214. doi:  10.1175/JTECH2033.1
    [7]
    Görsdorf U, Lehmann V, Bauter-Pfundstein M, et al. A 35-GHz polarimetric Doppler radar for long-term observations of cloud parameters-description of system and data processing. J Atmos Oceanic Technol, 2015, 32: 675-690. doi:  10.1175/JTECH-D-14-00066.1
    [8]
    Liu L P, Zheng J F, Ruan Z, et al. Comprehensive radar observation of clouds and precipitation over the Tibetan Plateau and preliminary analysis of cloud properties. J Meteor Res, 2015, 29(4): 547-561. http://www.cqvip.com/QK/88418X/201504/666234442.html
    [9]
    Tang Y J, Ma S Q, Yang L, et al. Observation and comparison of cloud-base heights by ground-based millimeter-wave cloud radar. J Appl Meteor Sci, 2015, 26(6): 680-687. doi:  10.11898/1001-7313.20150604
    [10]
    Zhong Z Y, Ma S Q, Yang L, et al. Progress of weather modification technologies and applications in China from 2008 to 2018. J Appl Meteor Sci, 2018, 29(4): 496-504. doi:  10.11898/1001-7313.20180410
    [11]
    Tao F, Guan L, Zhang X F, et al. Veriation and vertical structure of clear-air echo by Ka-band cloud radar. J Appl Meteor Sci, 2020, 31(6): 719-728. doi:  10.11898/1001-7313.20200607
    [12]
    Zhong L Z, Liu L P, Ge R S. Characteristics about the millimeter-wavelength radar and its status and prospect in and abroad. Advances in Earth Science, 2009, 24(4): 383-391. doi:  10.3321/j.issn:1001-8166.2009.04.004
    [13]
    Kropfli R A, Kelly R D. Meteorological research applications of mm-wave radar. Meteorol Atmos Phys, 1996, 59: 105-121. doi:  10.1007/BF01032003
    [14]
    Lhermitte R M. 94 GHz Doppler radar for cloud observation. J Atmos Oceanic Technol, 1987, 4: 36-48. doi:  10.1175/1520-0426(1987)004<0036:AGDRFC>2.0.CO;2
    [15]
    Sun H, Liu L P, Zheng J F. Comparison of Doppler spectral density data by different bands pointing vertically radars. J Appl Meteor Sci, 2018, 28(4): 447-457. doi:  10.11898/1001-7313.20170406
    [16]
    Shang J, Guo Y, Wu Q, et al. Airborne field campaign results of Ka-band precipitation measuring radar in China. J Appl Meteor Sci, 2011, 22(5): 590-596. doi:  10.3969/j.issn.1001-7313.2011.05.009
    [17]
    Babb D M, Verlinde J, Albrecht B A. Retrieval of cloud microphysical parameters from 94-GHz radar Dopple power spectra. J Atmos Oceanic Techol, 1999, 16: 489-503. doi:  10.1175/1520-0426(1999)016<0489:ROCMPF>2.0.CO;2
    [18]
    Pasqualucci F, Bartram B W, Kropfli R A, et al. A millimeter-wavelength dule-polarization Doppler radar for cloud and precipitation studies. J Appl Meteor Climatol, 1983, 22(5): 758-765. doi:  10.1175/1520-0450(1983)022<0758:AMWDPD>2.0.CO;2
    [19]
    Zhong L Z. Calibration and Capability Analysis of China New Generation of Cloud Radar-HMBQ and Its Preliminary Application in Retrieving Cloud Microphysics Parameter. Nanjing: Nanjing University of Information Science & Technology, 2009.
    [20]
    Zong R. Studies of Cloud Macro-and Microphysical Properties using China New Generation Millimeter-wavelength Radar. Nanjing: Nanjing University of Information Science & Technology, 2013.
    [21]
    Zheng J F. Doppler Spectral Data Processing Methods of Ka-band Multi-mode mm-wave Radar and Air Vertical Speed Retrieval in Clouds. Nanjing: Nanjing University of Information Science & Technology, 2016.
    [22]
    Liu L P, Ding H, Dong X B, et al. Applications of QC and merged Doppler spectral density data from Ka-band cloud radar to microphysics retrieval and comparison with airplane in situ observation. Remote Sensing, 2019, 11: 1595-1613. doi:  10.3390/rs11131595
    [23]
    Moran K P, Martner B E, Post M J, et al. An unattended cloud-profiling radar for use in climate research. Bull Amer Meteor Soc, 1998, 79: 443-455. doi:  10.1175/1520-0477(1998)079<0443:AUCPRF>2.0.CO;2
    [24]
    Ma S D. Research on Radar Return Signal MTI and Pulse Compression. Harbin: Harbin Engineering University, 2019.
    [25]
    Luke E P, Pavlos K, Johnson K L, et al. A technique for the automatic detection of insect clutter in cloud radar returns. J Atmos Oceanic Technol, 2008, 25(9): 1498-1513. doi:  10.1175/2007JTECHA953.1
    [26]
    Clothiaux E E, Ackerman T P, Mace G G, et al. Objective determination of cloud heights and radar refectivities using a combination of active remote sensors at the ARM CART sites. J Appl Meteor, 2000, 39: 645-665. doi:  10.1175/1520-0450(2000)039<0645:ODOCHA>2.0.CO;2
    [27]
    Geerts B, Miao Q. The use of millimeter Doppler radar echoes to estimate vertical air velocities in the fair-weather convective boundary layer. J Atmos Oceanic Technol, 2005, 22: 225-246. doi:  10.1175/JTECH1699.1
    [28]
    Zheng J F, Liu L P, Zeng Z M, et al. Ka-band millimeter wave cloud radar data quality control. J Infrared Millim Waves, 2016, 35(6): 748-757. https://www.cnki.com.cn/Article/CJFDTOTAL-HWYH201606018.htm
    [29]
    Liang H H, Zhang P Y, Ge R S. Study of data processing of wind fields from Doppler radar. J Appl Meteor Sci, 2002, 13(5): 591-601. doi:  10.3969/j.issn.1001-7313.2002.05.008
    [30]
    Cui Z H, Cheng M H, Wu Q L, et al. A technique of fast median filtering and its application to data quality control of Doppler radar. Plateau Meteorology, 2005, 24(5): 727-733. doi:  10.3321/j.issn:1000-0534.2005.05.011
    [31]
    Liu L. Study on the Pollution Meteorological Characteristics and Simulation of Bioaerosols Dispersion over Southeast Coastal Area of China. Nanjing: Nanjing University, 2011.
    [32]
    Lü L H, Liu W Q, Zhang T S, et al. Characteristics of boundary layer height in Jing-Jin-Ji Area based on lidar. Laser & Optoelectronics Progress, 2017, 54(1): 50-56.
    [33]
    Jiang D H, Wang C G, Wu D, et al. Diurnal variation of atmospheric boundary layer over Wushan station, Guangzhou using wind profiler radar. Journal of Tropical Meteorology, 2013, 29(1): 129-135. https://www.cnki.com.cn/Article/CJFDTOTAL-RDQX201301016.htm
  • 加载中
  • -->

Catalog

    Figures(7)  / Tables(2)

    Article views (1391) PDF downloads(160) Cited by()
    • Received : 2020-11-06
    • Accepted : 2021-01-18
    • Published : 2021-05-31

    /

    DownLoad:  Full-Size Img  PowerPoint