94/220 GHz星载雷达双波长比对非球形冰晶云参数敏感性分析
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摘要
利用不同形状冰晶的散射特性,获得了非球形冰晶云的94/220 GHz测云雷达双波长比,探讨了非球形冰晶云的双波长比与云内微物理参数的关系,分析了衰减前后的星载雷达反射率因子及双波长比的垂直廓线。结果表明:(1)双波长比可以反映小到0.1 mm中值尺度的冰粒子,对粒子总数、谱的形状参数不敏感,对粒子大小、形状、云衰减较敏感。(2)雷达灵敏度一定时,星载雷达可测云厚与雷达波长、冰含水量(IWC)的垂直分布、云厚及衰减有关;没有进行衰减订正时,双波长比和衰减有关,冰含水量越大,波长越短,衰减越大,双波长比最大值与可探测云厚有关。两部雷达可探测冰含水量为0.001—0.1 g/m~3、厚2 km的冰云;当云厚5 km、冰含水量垂直分布在0.001—0.2 g/m~3时,云厚的94%基本可以被220 GHz云雷达探测到。(3)如果两部雷达气象方程中用水的介电因子,测量回波强度应进行介电因子的订正后再计算双波长比。
The dual wavelength reflectivity ratio(DWR) of 94/220 GHz radar to non-spherical ice clouds was obtained based on the scattering characteristics of ice crystals with different shapes, and the relationships between the DWR and the cloud parameters were analyzed. The vertical profiles of the unattenuated and attenuated radar reflectivity factors and DWR were studied. The results are as follows.(1) The DWR is sensitive to the size and shape of particles, the attenuation from clouds and the median maximum dimension of the particles size distribution(PSD) that can even be as small as 0.1 mm, but insensitive to the particle concentration and shape parameters of the PSD.(2) When the sensitivity of radar receiver is certain, the ability of space-borne radars to detect cloud thickness depends on the wavelengths of radars, the vertical profiles of the ice water content(IWC), the thickness of the cloud and the attenuation. In the condition of no attenuation correction, the DWR related to the attenuation and the maximum is determined by the detected cloud thickness, while higher IWC and shorter wavelength correspond to larger attenuation. As a result, the two radars can detect the ice clouds with IWC=0.001-0.1 g/m~3 and thickness of 2 km. Furthermore, 94% of the cloud thickness can be explored for the ice clouds with IWC=0.001-0.2 g/m~3 and the thickness of 5 km.(3) When the dielectric factors of water are using in the two radars' meteorological equations, the DWR can only be obtained after directly detected echo intensity is corrected.
The dual wavelength reflectivity ratio(DWR) of 94/220 GHz radar to non-spherical ice clouds was obtained based on the scattering characteristics of ice crystals with different shapes, and the relationships between the DWR and the cloud parameters were analyzed. The vertical profiles of the unattenuated and attenuated radar reflectivity factors and DWR were studied. The results are as follows.(1) The DWR is sensitive to the size and shape of particles, the attenuation from clouds and the median maximum dimension of the particles size distribution(PSD) that can even be as small as 0.1 mm, but insensitive to the particle concentration and shape parameters of the PSD.(2) When the sensitivity of radar receiver is certain, the ability of space-borne radars to detect cloud thickness depends on the wavelengths of radars, the vertical profiles of the ice water content(IWC), the thickness of the cloud and the attenuation. In the condition of no attenuation correction, the DWR related to the attenuation and the maximum is determined by the detected cloud thickness, while higher IWC and shorter wavelength correspond to larger attenuation. As a result, the two radars can detect the ice clouds with IWC=0.001-0.1 g/m~3 and thickness of 2 km. Furthermore, 94% of the cloud thickness can be explored for the ice clouds with IWC=0.001-0.2 g/m~3 and the thickness of 5 km.(3) When the dielectric factors of water are using in the two radars' meteorological equations, the DWR can only be obtained after directly detected echo intensity is corrected.
引文
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Battaglia A,Tanelli S,Kollias P.2013.Polarization diversity for millimeter spaceborne Doppler radars:An answer for observing deep convection?J Atmos Oceanic Technol,30(12):2768-2787
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Baum B A,Heymsfield A J,Yang P,et al.2005.Bulk scattering properties for the remote sensing of ice clouds.Part I:Microphysical data and models.J Appl Meteor,44(12):1885-1895
Brown P R A,Francis P N.1995.Improved measurements of the ice water content in cirrus using a total-water probe.J Atmos Oceanic Sci Technol,12(2):410-414
Dowling D R,Radke L F.1990.A summary of the physical properties of cirrus clouds.J Appl Meteor,29(9):970-978
Fox N I,Illingworth A J.1997.The retrieval of stratocumulus cloud properties by ground-based cloud radar.J Appl Meteor,36(5):485-492
Fu Q.1996.An accurate parameterization of the solar radiative properties of cirrus clouds for climate models.J Climate,9(9):2058-2082
Heymsfield A J,Bansemer A,Field P R,et al.2002.Observations and parameterizations of particle size distributions in deep tropical cirrus and stratiform precipitating clouds:Results from in situ observations in TRMM field campaigns.J Atmos Sci,59(24):3457-3491
Heymsfield A J,Miloshevich L M.2003.Parameterizations for the cross-sectional area and extinction of cirrus and stratiform ice cloud particles.J Atmos Sci,60(7):936-956
Hogan R J,Illingworth A J,Sauvageot H.2000.Measuring crystal size in cirrus using 35- and 94-GHz radars.J Atmos Oceanic Technol,17(1):27-37
Hogan R J,Mittermaier M P,Illingworth A J.2006.The retrieval of ice water content from radar reflectivity factor and temperature and its use in evaluating a mesoscale model.J Appl Meteor Climatol,45(2):301-317
Kollias P,Clothiaux E E,Miller M A,et al.2007.Millimeter-wavelength radars:New frontier in atmospheric cloud and precipitation research.Bull Amer Meteor Soc,88(10):1608-1624
Kosarev A L,Mazin I P.1991.An empirical model of the physical structure of upper-layer clouds.Atmos Res,26(3):213-228
Kropfli R A,Matrosov S Y,Uttal T,et al.1995.Cloud physics studies with 8 mm wavelength radar.Atmos Res,35(2-4):299-313
Lhermitte R.1990.Attenuation and scattering of millimeter wavelength radiation by clouds and precipitation.J Atmos Oceanic Technol,7(3):464-479
Lhermitte R M.1988.Observation of rain at vertical incidence with a 94 GHz Doppler radar:An insight on Mie scattering.Geophys Res Lett,15(10):1125-1128
Lhermitte R M.2002.Centimeter & millmeter Wavelength Radars in Meteorology.Lhermitte Publications,238-496
Liu G S.2008.A database of microwave single-scattering properties for nonspherical ice particles.Bull Amer Meteor Soc,89(10):1563-1570
M?tzler C.2006.Microwave Dielectric Properties of Ice,I:Thermal Microwave Radiation-Applications for Remote Sensing.Stevenage:Institution of Engineering and Technology,455-462
Mead J B,Mcintosh R E,Vandemark D,et al.1989.Remote sensing of clouds and fog with a 1.4-mm radar.J Atmos Oceanic Technol,6(6):1090-1097
Sassen K,Campbell J R,Zhu J,et al.2005.Lidar and triple-wavelength Doppler radar measurements of the melting layer:A revised model for dark- and brightband phenomena.J Appl Meteor,44(3):301-312
Stephens G L,Vane D G,Tanelli S,et al.2008.CloudSat mission:Performance and early science after the first year of operation.J Geophys Res,113(D8):D00A18
Wu J X,Wei M,Hang X,et al.2014.The first observed cloud echoes and microphysical parameter retrievals by China's 94-GHz cloud radar.J Meteor Res,28(3):430-443
王喆,王振会,曹晓钟.2016.毫米波雷达与无线电探空对云垂直结构探测的一致性分析.气象学报,74(5):815-826.Wang Z,Wang Z H,Cao X Z.2016.Consistency analysis for cloud vertical structure derived from millimeter cloud radar and radiosonde profiles.Acta Meteor Sinica,74(5):815-826 (in Chinese)
吴举秀,魏鸣,周杰.2014.94 GHz云雷达回波及测云能力分析.气象学报,72(2):402-416.Wu J X,Wei M,Zhou J.2014.Echo and capability analysis of 94 GHz cloud radars.Acta Meteor Sinica,72(2):402-416 (in Chinese)
吴举秀,窦芳丽,安大伟等.2016.非球形冰晶在94/220 GHz毫米波的散射特性模拟计算.红外与毫米波学报,35(3):377-384.Wu J X,Dou F L,An D W,et al.2016.Simulation of scattering characteristics of non-spherical ice crystals with 94/220 GHz millimeter-wavelength.J Infrared Millim Waves,35(3):377-384 (in Chinese)
吴举秀,魏鸣,苏涛等.2017.W波段和Ka波段云雷达探测回波对比分析.海洋气象学报,37(2):57-64.Wu J X,Wei M,Su T,et al.2017.Comparison of the echoes detected by W-band and Ka-band cloud radars.J Mar Meteor,37(2):57-64 (in Chinese)
张培昌,王振会.2001.天气雷达回波衰减订正算法的研究(Ⅰ):理论分析.高原气象,20(1):1-5.Zhang P C,Wang Z H.2001.A study on algorithm to make attenuation correction to radar observations of radar reflectivity factor (Ⅰ):Theoretical analysis.Plateau Meteor,20(1):1-5 (in Chinese)
仲凌志,刘黎平,葛润生.2009.毫米波测云雷达的特点及其研究现状与展望.地球科学进展,24(4):383-391.Zhong L Z,Liu L P,Ge R S.2009.Characteristics about the millimeter-wavelength radar and its status and prospect in and abroad.Adv Earth Sci,24(4):383-391 (in Chinese)
An D W,Shang J,Wu Q,et al.2014.Remote sensing of clouds and evaluation with a 220 GHz radar//Proceedings of SPIE 9259,Remote Sensing of the Atmosphere,Clouds,and Precipitation V.Beijing,China:SPIE
Battaglia A,Tanelli S,Kollias P.2013.Polarization diversity for millimeter spaceborne Doppler radars:An answer for observing deep convection?J Atmos Oceanic Technol,30(12):2768-2787
Battaglia A,Westbrook C D,Kneifel S,et al.2014.G band atmospheric radars:New frontiers in cloud physics.Atmos Meas Tech,7(6):1527-1546
Baum B A,Heymsfield A J,Yang P,et al.2005.Bulk scattering properties for the remote sensing of ice clouds.Part I:Microphysical data and models.J Appl Meteor,44(12):1885-1895
Brown P R A,Francis P N.1995.Improved measurements of the ice water content in cirrus using a total-water probe.J Atmos Oceanic Sci Technol,12(2):410-414
Dowling D R,Radke L F.1990.A summary of the physical properties of cirrus clouds.J Appl Meteor,29(9):970-978
Fox N I,Illingworth A J.1997.The retrieval of stratocumulus cloud properties by ground-based cloud radar.J Appl Meteor,36(5):485-492
Fu Q.1996.An accurate parameterization of the solar radiative properties of cirrus clouds for climate models.J Climate,9(9):2058-2082
Heymsfield A J,Bansemer A,Field P R,et al.2002.Observations and parameterizations of particle size distributions in deep tropical cirrus and stratiform precipitating clouds:Results from in situ observations in TRMM field campaigns.J Atmos Sci,59(24):3457-3491
Heymsfield A J,Miloshevich L M.2003.Parameterizations for the cross-sectional area and extinction of cirrus and stratiform ice cloud particles.J Atmos Sci,60(7):936-956
Hogan R J,Illingworth A J,Sauvageot H.2000.Measuring crystal size in cirrus using 35- and 94-GHz radars.J Atmos Oceanic Technol,17(1):27-37
Hogan R J,Mittermaier M P,Illingworth A J.2006.The retrieval of ice water content from radar reflectivity factor and temperature and its use in evaluating a mesoscale model.J Appl Meteor Climatol,45(2):301-317
Kollias P,Clothiaux E E,Miller M A,et al.2007.Millimeter-wavelength radars:New frontier in atmospheric cloud and precipitation research.Bull Amer Meteor Soc,88(10):1608-1624
Kosarev A L,Mazin I P.1991.An empirical model of the physical structure of upper-layer clouds.Atmos Res,26(3):213-228
Kropfli R A,Matrosov S Y,Uttal T,et al.1995.Cloud physics studies with 8 mm wavelength radar.Atmos Res,35(2-4):299-313
Lhermitte R.1990.Attenuation and scattering of millimeter wavelength radiation by clouds and precipitation.J Atmos Oceanic Technol,7(3):464-479
Lhermitte R M.1988.Observation of rain at vertical incidence with a 94 GHz Doppler radar:An insight on Mie scattering.Geophys Res Lett,15(10):1125-1128
Lhermitte R M.2002.Centimeter & millmeter Wavelength Radars in Meteorology.Lhermitte Publications,238-496
Liu G S.2008.A database of microwave single-scattering properties for nonspherical ice particles.Bull Amer Meteor Soc,89(10):1563-1570
M?tzler C.2006.Microwave Dielectric Properties of Ice,I:Thermal Microwave Radiation-Applications for Remote Sensing.Stevenage:Institution of Engineering and Technology,455-462
Mead J B,Mcintosh R E,Vandemark D,et al.1989.Remote sensing of clouds and fog with a 1.4-mm radar.J Atmos Oceanic Technol,6(6):1090-1097
Sassen K,Campbell J R,Zhu J,et al.2005.Lidar and triple-wavelength Doppler radar measurements of the melting layer:A revised model for dark- and brightband phenomena.J Appl Meteor,44(3):301-312
Stephens G L,Vane D G,Tanelli S,et al.2008.CloudSat mission:Performance and early science after the first year of operation.J Geophys Res,113(D8):D00A18
Wu J X,Wei M,Hang X,et al.2014.The first observed cloud echoes and microphysical parameter retrievals by China's 94-GHz cloud radar.J Meteor Res,28(3):430-443