Polarization Diversity for Millimeter Spaceborne Doppler Radars: An Answer for Observing Deep Convection?

Alessandro Battaglia University of Leicester, Leicester, United Kingdom

Search for other papers by Alessandro Battaglia in
Current site
Google Scholar
PubMed
Close
,
Simone Tanelli Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California

Search for other papers by Simone Tanelli in
Current site
Google Scholar
PubMed
Close
, and
Pavlos Kollias Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Canada

Search for other papers by Pavlos Kollias in
Current site
Google Scholar
PubMed
Close
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

Spaceborne Doppler radars have the potential to provide key missing observations of convective vertical air motions especially over the tropical oceans. Such measurements can improve understanding of the role of tropical convection in vertical energy transport and its interaction with the environment. Several millimeter wavelength Doppler radar concepts have been proposed since the 1990s. The Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE) Cloud Profiling Radar (CPR) will be the first Dopplerized atmospheric radar in space but has not been optimized for Doppler measurements in deep convective clouds.

The key challenge that constrains the CPR performance in convective clouds is the range–Doppler dilemma. Polarization diversity (PD) offers a solution to this constraint by decoupling the coherency (Doppler) requirement from the unambiguous range requirement. Careful modeling of the radar signal depolarization and its impact on radar receiver channel cross talk is needed to accurately assess the performance of the PD approach.

The end-to-end simulator presented in this work allows reproduction of the signal sensed by a Doppler radar equipped with polarization diversity when overpassing realistic three-dimensional convective cells, with all relevant cross-talk sources accounted for. The notional study highlights that multiple scattering is the primary source of cross talk, highly detrimental for millimeter Doppler velocity accuracy. The ambitious scientific requirement of 1 m s−1 accuracy at 500-m integration for reflectivities above −15 dBZ are within reach for a W-band radar with a 2.5-m antenna with optimal values of the pulse-pair interval between 20 and 30 μs but only once multiple scattering and ghost-contaminated regions are screened out. The identification of such areas is key for Doppler accuracies and can be achieved by employing an interlaced pulse-pair mode that measures the cross and the copolar reflectivities. To mitigate the impact of attenuation and multiple scattering, the Ka band has been considered as either alternative or additional to the W band. However, a Ka system produces worse Doppler performances than a W-band system with the same 2.5-m antenna size. Furthermore, in deep convection it results in similar levels of multiple scattering and therefore it does not increase significantly the depth of penetration. In addition, the larger footprint causes stronger nonuniform beam-filling effects. One advantage of the Ka-band option is the larger Nyquist velocity that tends to reduce the Doppler accuracies. More significant benefits are derived from the Ka band when observing precipitation not as intense as the deep convection is considered here.

This study demonstrates that polarization diversity indeed represents a very promising methodology capable of significantly reducing aliasing and Doppler moment estimate errors, two main error sources for Doppler velocity estimates in deep convective systems and a key step to achieving typical mission requirements for convection-oriented millimeter radar-based spaceborne missions.

Corresponding author address: Alessandro Battaglia, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom. E-mail: ab474@le.ac.uk

Abstract

Spaceborne Doppler radars have the potential to provide key missing observations of convective vertical air motions especially over the tropical oceans. Such measurements can improve understanding of the role of tropical convection in vertical energy transport and its interaction with the environment. Several millimeter wavelength Doppler radar concepts have been proposed since the 1990s. The Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE) Cloud Profiling Radar (CPR) will be the first Dopplerized atmospheric radar in space but has not been optimized for Doppler measurements in deep convective clouds.

The key challenge that constrains the CPR performance in convective clouds is the range–Doppler dilemma. Polarization diversity (PD) offers a solution to this constraint by decoupling the coherency (Doppler) requirement from the unambiguous range requirement. Careful modeling of the radar signal depolarization and its impact on radar receiver channel cross talk is needed to accurately assess the performance of the PD approach.

The end-to-end simulator presented in this work allows reproduction of the signal sensed by a Doppler radar equipped with polarization diversity when overpassing realistic three-dimensional convective cells, with all relevant cross-talk sources accounted for. The notional study highlights that multiple scattering is the primary source of cross talk, highly detrimental for millimeter Doppler velocity accuracy. The ambitious scientific requirement of 1 m s−1 accuracy at 500-m integration for reflectivities above −15 dBZ are within reach for a W-band radar with a 2.5-m antenna with optimal values of the pulse-pair interval between 20 and 30 μs but only once multiple scattering and ghost-contaminated regions are screened out. The identification of such areas is key for Doppler accuracies and can be achieved by employing an interlaced pulse-pair mode that measures the cross and the copolar reflectivities. To mitigate the impact of attenuation and multiple scattering, the Ka band has been considered as either alternative or additional to the W band. However, a Ka system produces worse Doppler performances than a W-band system with the same 2.5-m antenna size. Furthermore, in deep convection it results in similar levels of multiple scattering and therefore it does not increase significantly the depth of penetration. In addition, the larger footprint causes stronger nonuniform beam-filling effects. One advantage of the Ka-band option is the larger Nyquist velocity that tends to reduce the Doppler accuracies. More significant benefits are derived from the Ka band when observing precipitation not as intense as the deep convection is considered here.

This study demonstrates that polarization diversity indeed represents a very promising methodology capable of significantly reducing aliasing and Doppler moment estimate errors, two main error sources for Doppler velocity estimates in deep convective systems and a key step to achieving typical mission requirements for convection-oriented millimeter radar-based spaceborne missions.

Corresponding author address: Alessandro Battaglia, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom. E-mail: ab474@le.ac.uk
Save
  • Allan, R. P., and Soden B. J. , 2008: Atmospheric warming and the amplification of precipitation extremes. Science, 321, 14811484, doi:10.1126/science.1160787.

    • Search Google Scholar
    • Export Citation
  • Amayenc, P., Testud J. , and Marzoug M. , 1993: Proposal for a spaceborne dual-beam rain radar with Doppler capability. J. Atmos. Oceanic Technol., 10, 262276.

    • Search Google Scholar
    • Export Citation
  • Bacmeister, J. T., and Stephens G. L. , 2011: Spatial statistics of likely convective clouds in CloudSat data. J. Geophys. Res., 116, D04104, doi:10.1029/2010JD014444.

    • Search Google Scholar
    • Export Citation
  • Battaglia, A., and Tanelli S. , 2011: DOMUS: Doppler Multiple Scattering Simulator. IEEE Trans. Geosci. Remote Sens., 49, 442450, doi:10.1109/TGRS.2010.2052818.

    • Search Google Scholar
    • Export Citation
  • Battaglia, A., Ajewole M. O. , and Simmer C. , 2007: Evaluation of radar multiple scattering effects in CloudSat configuration. Atmos. Chem. Phys., 7, 17191730.

    • Search Google Scholar
    • Export Citation
  • Battaglia, A., Kobayashi S. , Tanelli S. , Im E. , and Simmer C. , 2008: Multiple scattering effects in pulsed radar systems: An intercomparison study. J. Atmos. Oceanic Technol., 25, 1556–1567.

    • Search Google Scholar
    • Export Citation
  • Battaglia, A., Tanelli S. , Kobayashi S. , Zrnić D. , Hogan R. , and Simmer C. , 2010: Multiple-scattering in radar systems: A review. J. Quant. Spectrosc. Radiat. Transfer, 111, 917947, doi:10.1016/j.jqsrt.2009.11.024.

    • Search Google Scholar
    • Export Citation
  • Battaglia, A., Augustynek T. , Tanelli S. , and Kollias P. , 2011: Multiple scattering identification in spaceborne W-band radar measurements of deep convective cores. J. Geophys. Res., 116, D19201, doi:10.1029/2011JD016142.

    • Search Google Scholar
    • Export Citation
  • Bennartz, R., Joe P. , Loehnert U. , Koskinen J. , Skofronick-Jackson G. , and Vane D. , Eds., 2011: Report on the third international workshop on space-based snowfall measurement. 30 pp. [Available online at http://www.isac.cnr.it/~ipwg/meetings/grainau-2011/iwssm_3_report_final.pdf.]

  • Doviak, R. J., and Sirmans D. , 1973: Doppler radar with polarization diversity. J. Atmos. Sci., 30, 737–738.

  • Doviak, R. J., and Zrnić D. S. , 1984: Doppler Radar and Weather Observations. Academic Press, 458 pp.

  • Durden, S. L., and Coauthors, 2011: A cloud and precipitation radar system concept for the ACE Mission. JPL Tech. Rep., 4 pp. [Available online at http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/42129/1/11-1720.pdf.]

  • Heymsfield, G. M., Tian L. , Heymsfield A. J. , Li L. , and Guimond S. , 2010: Characteristics of deep tropical and subtropical convection from nadir-viewing high-altitude airborne Doppler radar. J. Atmos. Sci.,67, 285–308.

  • Hu, Y.-X., Winker D. , Yang P. , Baum B. , Poole L. , and Vann L. , 2001: Identification of cloud phase from PICASSO-CENA lidar depolarization: a multiple scattering sensitivity study. J. Quant. Spectrosc. Radiat. Transfer, 70, 569579.

    • Search Google Scholar
    • Export Citation
  • Joe, P., and Coauthors, 2010: The polar precipitation measurement mission. Proc. Sixth European Conf. on Radar Meteorology and Hydrology: Satellite Radar Measurements and Hydro-Meteorological Applications, Sibiu, Romania, ERAD, 18 pp. [Available online at http://www.erad2010.org/pdf/oral/tuesday/satellite/01_ERAD2010_Joe.pdf.]

  • Kobayashi, S., Kumagai H. , and Kuroiwa H. , 2002: A proposal of pulse-pair Doppler operation on a spaceborne cloud-profiling radar in the W band. J. Atmos. Oceanic Technol.,19, 1294–1306.

  • Kobayashi, S., Kumagai H. , and Iguchi T. , 2003: Accuracy evaluation of Doppler velocity on a spaceborne weather radar through a random signal simulation. J. Atmos. Oceanic Technol.,20, 944–949.

  • Kobayashi, S., Oguchi T. , Tanelli S. , and Im E. , 2007: Backscattering enhancement on spheroid-shaped hydrometeors: Considerations in water and ice particles of uniform size and Marshall-Palmer distributed rains. Radio Sci.,42, RS2001, doi:10.1029/2006RS003503.

  • Lhermitte, R., 1990: Attenuation and scattering of millimeter wavelength radiation by clouds and precipitation. J. Atmos. Oceanic Technol., 7, 464479.

    • Search Google Scholar
    • Export Citation
  • Liao, L., Meneghini R. , and Iguchi T. , 1999: Simulations of mirror image returns of air/space-borne radars in rain and their applications in estimating path attenuation. IEEE Trans. Geosci. Remote Sens., 37, 11071121.

    • Search Google Scholar
    • Export Citation
  • Luo, G. Y., and Stephens G. L. , 2010: Use of A-Train data to estimate convective buoyancy and entrainment rate. Geophys. Res. Lett., 37, L09804, doi:10.1029/2010GL042904.

    • Search Google Scholar
    • Export Citation
  • Luo, Z., Liu G. Y. , and Stephens G. L. , 2008: CloudSat adding new insight into tropical penetrating convection. Geophys. Res. Lett., 35, L19819, doi:10.1029/2008GL035330.

    • Search Google Scholar
    • Export Citation
  • National Research Council of the National Academies, 2007: Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. National Academies Press, 456 pp.

  • Parazoo, N. C., Denning A. S. , Berry J. A. , Wolf A. , Randall D. A. , Kawa S. R. , Pauluis O. , and Doney S. C. , 2011: Moist synoptic transport of CO2 along the mid-latitude storm track. Geophys. Res. Lett., 38, L09804, doi:10.1029/2011GL047238.

    • Search Google Scholar
    • Export Citation
  • Pazmany, A., Galloway J. , Mead J. , Popstefanija I. , McIntosh R. , and Bluestein H. , 1999: Polarization diversity pulse-pair technique for millimeter-wave Doppler radar measurements of severe storm features. J. Atmos. Oceanic Technol., 16, 19001910.

    • Search Google Scholar
    • Export Citation
  • Phillips, V. T. J., and Donner L. J. , 2006: Cloud microphysics, radiation and vertical velocities in two- and three-dimensional simulations of deep convection. Quart. J. Roy. Meteor. Soc., 132, 3011–3033, doi:10.1256/qj.05.171.

    • Search Google Scholar
    • Export Citation
  • Sachidananda, M., and Zrnić D. , 2002: An improved clutter filtering and spectral moment estimation algorithm for staggered PRT sequences. J. Atmos. Oceanic Technol., 19, 20092019.

    • Search Google Scholar
    • Export Citation
  • Schutgens, N. A. J., 2008: Simulated Doppler radar observations of inhomogeneous clouds: Application to the EarthCARE space mission. J. Atmos. Oceanic Technol., 25, 15141528.

    • Search Google Scholar
    • Export Citation
  • Skamarock, W. C., Klemp J. B. , Dudhia J. , Gill D. O. , Barker D. M. , Wang W. , and Powers J. G. , 2007: A description of the Advanced Research WRF version 2. NCAR Tech. Note NCAR/TN-468+STR, 88 pp.

  • Stephens, G. L., and Coauthors, 2010: Dreary state of precipitation in global models. J. Geophys. Res., 115, D24211, doi:10.1029/2010JD014532.

    • Search Google Scholar
    • Export Citation
  • Sy, O., Tanelli S. , Takahashi N. , Ohno Y. , Horie H. , and Kollias P. , 2013: Simulation of EarthCARE spaceborne Doppler radar products using ground-based and airborne data: Effects of aliasing and nonuniform beam-filling. IEEE Trans. Geosci. Remote Sens., doi:10.1109/TGRS.2013.2251639, in press.

    • Search Google Scholar
    • Export Citation
  • Tanelli, S., Im E. , Durden S. L. , Facheris L. , and Giuli D. , 2002a: The effects of nonuniform beam filling on vertical rainfall velocity measurements with a spaceborne Doppler radar. J. Atmos. Oceanic Technol., 19, 10191034.

    • Search Google Scholar
    • Export Citation
  • Tanelli, S., Im E. , Facheris L. , and Smith E. A. , 2002b: DFT-based spectral moment estimators for spaceborne Doppler precipitation radar. Proc. Symp. on Remote Sensing of the Atmosphere, Environment and Space, 4894, Hangzhou, China, SPIE, doi:10.1117/12.467754.

  • Tanelli, S., Im E. , Stephen L. F. , and Durden L. , 2003: Measuring vertical rainfall velocity through spaceborne Doppler radar: Performance analysis and system requirements. IGARSS ‘03: Int. Geoscience and Remote Sensing Symp., Toulouse, France, IEEE, 878–880.

  • Tanelli, S., Durden S. , Im E. , Pak K. , Reinke D. , Partain P. , Haynes J. , and Marchand R. , 2008a: CloudSat's cloud profiling radar after 2 years in orbit: Performance, calibration, and processing. IEEE Trans. Geosci. Remote Sens., 46, 35603573.

    • Search Google Scholar
    • Export Citation
  • Tanelli, S., Im E. , Durden S. , Giuli D. , and Facheris L. , 2008b: Spaceborne Doppler radars for atmospheric dynamics and energy budget studies. Radar Conf., Rome, Italy, IEEE, 16, doi:10.1109/RADAR.2008.4721127.

  • Tanelli, S., Durden S. L. , Im E. , Heymsfield G. , Racette P. , and Starr D. , 2009: Next-generation spaceborne cloud profiling radars. Radar Conf., Pasadena, CA, IEEE, 14, doi:10.1109/RADAR.2009.4977116.

  • Torres, S. M., Dubel Y. F. , and Zrnić D. S. , 2004: Design, implementation, and demonstration of a staggered PRT algorithm for the WSR-88D. J. Atmos. Oceanic Technol., 21, 13891399.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., Dai A. , Rasmussen R. M. , and Parsons D. B. , 2003: The changing character of precipitation. Bull. Amer. Meteor. Soc.,84, 1205–1217.

  • Tridon, F., Battaglia A. , and Kollias P. , 2013: Signal postprocessing and reflectivity calibration of the Atmospheric Radiation Measurement program 915-MHz wind profilers. J. Atmos. Oceanic Technol., 30, 1038–1054.

    • Search Google Scholar
    • Export Citation
  • Ulaby, F. T., Moore R. K. , and Fung A. K. , 1986: Microwave Remote Sensing Active and Passive. Artech House, 608 pp.

  • van den Heever, S., and Cotton W. , 2004: The impact of hail size on simulated supercell storms. J. Atmos. Sci., 61, 15961609.

  • Wolde, M., and Vali G. , 2001: Polarimetric signatures from ice crystals observed at 95 GHz in winter clouds. Part I: Dependence on crystal form. J. Atmos. Sci., 58, 828841.

    • Search Google Scholar
    • Export Citation
  • Yano, J.-I., Machulskaya E. , Bechtold P. , and Plant R. S. , 2013: Bells and whistles of convection parameterization. Bull. Amer. Meteor. Soc.,94, ES5–ES7.

  • Zhang, G. J., and Song X. , 2009: Interaction of deep and shallow convection is key to Madden-Julian oscillation simulation. Geophys. Res. Lett., 36, L09708, doi:10.1029/2009GL037340.

    • Search Google Scholar
    • Export Citation
  • Zrnić, D. S., 1975: Simulation of weatherlike Doppler spectra and signal. J. Appl. Meteor., 14, 619620.

  • Zrnić, D. S., 1977: Spectral moment estimates from correlated pulse pairs. IEEE Trans. Aerosp. Electron. Syst., AES-13, 344354.

  • Zrnić, D. S., 1979: Estimation of spectral moments for weather echoes. IEEE Trans. Geosci. Electron., GE-17, 113128.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 877 368 132
PDF Downloads 463 146 11