Journal of Earth System Science

, Volume 122, Issue 4, pp 947–956 | Cite as

Comparison of CloudSat and TRMM radar reflectivities


Comparison of reflectivity data of radars onboard CloudSat and TRMM is performed using coincident overpasses. The contoured frequency by altitude diagrams (CFADs) are constructed for two cases: (a) only include collocated vertical profiles that are most likely to be raining and (b) include all collocated profiles along with cloudy pixels falling within a distance of about 50 km from the centre point of coincidence. Our analysis shows that for both cases, CloudSat underestimates the radar reflectivity by about 10 dBZ compared to that of TRMM radar below 15 km altitude. The difference is well outside the uncertainty value of ~2 dBZ of each radar. Further, CloudSat reflectivity shows a decreasing trend while that of TRMM radar an increasing trend below 4 km height. Basically W-band radar that CloudSat flies suffers strong attenuation in precipitating clouds and its reflectivity value rarely exceeds 20 dBZ though its technical specification indicates the upper measurement limit to be 40 dBZ. TRMM radar, on the other hand, cannot measure values below 17 dBZ. In fact combining data from these two radars seems to give a better overall spatial structure of convective clouds.


CloudSat CPR TRMM PR CFADs radar reflectivity 


  1. Adeyewa Z D and Nakamura K 2003 Validation of TRMM radar rainfall data over major climatic regions in Africa; J. Appl. Meteorol. 42 331–347.CrossRefGoogle Scholar
  2. Barker H W, Korolev A V, Hudak D R, Strapp J W, Strawbridge K B and Wolde M 2008 A comparison between CloudSat and aircraft data for a multilayer, mixed phase cloud system during the Canadian CloudSat-CALIPSO Validation Project; J. Geophys. Res. 113 D00A16, doi: 10.1029/2008JD009971.CrossRefGoogle Scholar
  3. Behrangi A, Kuber T and Lambrigtsen B 2012 Phenomenological description of tropical clouds using CloudSat cloud classification; Mon. Weather Rev. 140 3235–3249.CrossRefGoogle Scholar
  4. Carty H M and Kuo K S 2008 A report: 2D-CloudSat-TRMM product description version 1.0; CloudSat Project, A NASA Earth system pathfinder mission.Google Scholar
  5. Casey S P F, Dessler A E and Schumacher C 2007 Frequency of tropical precipitating clouds as observed by the Tropical Rainfall Measuring Mission precipitation radar and ICESat/Geoscience laser altimeter system; J. Geophys. Res. 112 D14215, doi: 10.1029/2007JD008468.CrossRefGoogle Scholar
  6. Casey S P F, Fetzer E J and Kahn B H 2012 Revised identification of tropical oceanic cumulus congestus as viewed by CloudSat; Atmos. Chem. Phys. 12 1587–1595.CrossRefGoogle Scholar
  7. Cetrone J and Houze Jr R A 2009 Anvil clouds of tropical mesoscale convective systems in monsoon regions; Quart. J. Roy. Meteorol. Soc. 135 305–317.CrossRefGoogle Scholar
  8. Charney J G 1969 The intertropical convergence zone and the Hadley circulation of the atmosphere; Proc. WMO/IUGG Symposium on Numerical Weather Prediction, Tokyo, Japan, pp. III-73–79.Google Scholar
  9. CIMO 2008 Guide to Meteorological Instruments and Methods of Observation; Secretariat of the WMO. Part II Observing methods. WMO No. 8, 7th edn, pp. II.9-6–12.Google Scholar
  10. Cotton W R and Anthes R A 1989 Storm and cloud dynamics; Chapter 6, Academic Press, New York, p. 882.Google Scholar
  11. Diner D J, Beckert J C, Reilly T H, Bruegge C J, Conel J E, Kahn R A, Martonchik J V, Ackerman T P, Davies R, Gerstl S A W, Gordon H R, Muller J P, Myneni R B, Sellers P J, Pinty B and Verstraete M M 1998 Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview; IEEE Trans. Geosci. Remote Sens. 36 1072–1087.CrossRefGoogle Scholar
  12. Dinku T, Ruiz F, Connor S J and Ceccato P 2010 Validation and intercomparison of satellite rainfall estimates over Colombia; J. Appl. Meteorol. Climatol. 49 1004–1014.CrossRefGoogle Scholar
  13. Franchito S H, Rao V B, Vasques A C, Santo C M E and Conforte J C 2009 Validation of TRMM precipitation radar monthly rainfall estimates over Brazil; J. Geophys. Res. 114 D02105, doi: 10.1029/2007JD009580.CrossRefGoogle Scholar
  14. Gorgucci E and Chandrasekar V 2005 Evaluation of attenuation correction methodology for dual-polarization radars: Application to X-Band systems; J. Atmos. Ocean. Tech. 22 1195–1206.CrossRefGoogle Scholar
  15. Gourley J J, Hong Y, Flmaig Z L, Li L and Wang J 2010 Intercomparison of rainfall estimates from radar, satellite, gauge, and combinations for a season of record rainfall; J. Appl. Meteorol. Climatol. 49 437–452.CrossRefGoogle Scholar
  16. Haynes J M and Stephens G L 2007 Tropical oceanic cloudiness and the incidence of precipitation early results from CloudSat; Geophys. Res. Lett. 34 L09811, doi: 10.1029/2007GL029335.CrossRefGoogle Scholar
  17. Hence D A and Houze Jr R A 2011 Vertical structure of tropical cyclones with concentric eyewalls as seen by the TRMM precipitation radar; J. Atmos. Sci. 69 1021–1036.CrossRefGoogle Scholar
  18. Holton J R 2004 An introduction to dynamic meteorology; Chapter 11; 4th edn, Elsevier Academic Press, New York, p. 531.Google Scholar
  19. Houze Jr R A 1993 Cloud Dynamics. Academic Press, San Diego, pp. 112–114.Google Scholar
  20. Hudak D, Rodriguez P and Donaldson N 2008 Validation of the CloudSat precipitation occurrence algorithm using the Canadian C-band radar network; J. Geophys. Res. 113, D00A07, doi: 10.1029/2008JD009992.CrossRefGoogle Scholar
  21. Iguchi T and Meneghini R 1994 Intercomparison of single frequency methods for retrieving a vertical rain profile from airborne or space borne data; J. Atmos. Ocean. Tech. 11 1507–1516.CrossRefGoogle Scholar
  22. Kawanishi T, Kuroiwa H, Kojima M, Oikawa K, Kozu T, Kumagai H, Okamoto K, Okumura M, Nakatsuka H and Nishikawa K 2000 TRMM Precipitation Radar; Adv. Spac. Res. 25 969–972.CrossRefGoogle Scholar
  23. Kerr R A 2009 Clouds appear to be big, bad player in global warming; Science 325 376.CrossRefGoogle Scholar
  24. Kim S W, Chung E S, Yoon S C, Sohn B J and Sugimoto N 2011 Intercomparisons of cloud-top and cloud-base heights from ground-based Lidar, CloudSat and CALIPSO measurements; Int. J. Rem. Sens. 32 1179–1197.CrossRefGoogle Scholar
  25. King M D, Kaufman Y J, Menzel W P and Tanré D 1992 Remote sensing of cloud, aerosol, and water vapor properties from the moderate resolution imaging spectrometer (MODIS); IEEE Trans. Geosci. Rem. Sens. 30 2–27.CrossRefGoogle Scholar
  26. Kollias P, Clothiaux E E, Miller M A, Albrecht B A, Stephens G L and Ackerman T P 2007 Millimeter-Wavelength Radars: New frontier in atmospheric cloud and precipitation research; Bull. Am. Meteorol. Soc. 88 1608–1624.CrossRefGoogle Scholar
  27. Kummerow C, Barnes W, Kozu T, Shiue J and Simpson J 1998 The tropical rainfall measuring mission (TRMM) sensor package; J. Atmos. Ocean. Tech. 15 809–817.CrossRefGoogle Scholar
  28. Kummerow C, Simpson J, Thiele O, Barnes W, Chang A T C, Stocker E, Adler R F, Hou A, Kakar R, Wentz F, Ashcroft P, Kozu T, Hong Y, Okamoto K, Iguchi T, Kuroiwa H, Im E, Haddad Z, Huffman G, Ferrier B, Olson W S, Zipser E, Smith E A, Wilheit T T, North G, Krishnamurti T N and Nakamura K 2000 The status of the Tropical Rainfall Measuring Mission (TRMM) after two years in orbit; J. Appl. Meteorol. 39 1965–1982.CrossRefGoogle Scholar
  29. Li W and Schumacher C 2011 Thick anvils as viewed by the TRMM precipitation radar; J. Climate 24 1718–1735.CrossRefGoogle Scholar
  30. Liu C and Zipser E J 2008 Diurnal cycles of precipitation, clouds, and lightning in the tropics from 9 years of TRMM observations; Geophys. Res. Lett. 35 L04819, doi: 10.1029/2007GL032437.CrossRefGoogle Scholar
  31. 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.CrossRefGoogle Scholar
  32. Mace G G, Marchand R, Zhang Q and Stephens G L 2007 Global hydrometeor occurrence as observed by CloudSat initial observations from summer 2006; Geophys. Res. Lett. 34 L09808, doi: 10.1029/2006GL029017.CrossRefGoogle Scholar
  33. Marchand R T, Mace G, Ackerman T and Stephens G L 2008 Hydrometeor detection using CloudSat – an earth orbiting 94 GHz cloud radar; J. Atmos. Ocean. Tech. 25 519–533.CrossRefGoogle Scholar
  34. Masunga H and Kummerow C D 2006 Observations of tropical precipitating clouds ranging from shallow to deep convective systems; Geophys. Res. Lett. 33 L16805, doi: 10.1029/2006GL026547.CrossRefGoogle Scholar
  35. Nair S, Srinivasan G and Nemani R 2009 Evaluation of multi-satellite TRMM derived rainfall estimates over a western state of India; J. Meteorol. Soc. Japan 87 927–939.CrossRefGoogle Scholar
  36. Nicholson S E, Some B, Mccollum J, Nelkin E, Klotter D, Berte Y, Diallo B M, Gaye I, Kpabeba G, Ndiaye O, Noukpozounkou J N, Tanu M M, Thiam A, Toure A A and Traore A K 2003a Validation of TRMM and other rainfall estimates with a high-density gauge dataset for west Africa. Part I: Validation of GPCC rainfall product and pre-TRMM satellite and blended products; J. Appl. Meteorol. 42 1337–1354.CrossRefGoogle Scholar
  37. Nicholson S E, Some B, Mccollum J, Nelkin E, Klotter D, Berte Y, Diallo B M, Gaye I, Kpabeba G, Ndiaye O, Noukpozounkou J N, Tanu M M, Thiam A, Toure A A and Traore A K 2003b Validation of TRMM and other rainfall estimates with a high-density gauge dataset for west Africa. Part II: Validation of TRMM rainfall products; J. Appl. Meteorol. 42 1355–1368.CrossRefGoogle Scholar
  38. Protat A, Bouniol D, O’Connor E J, Baltink H K, Verlinde J and Widener K 2011 CloudSat as a global calibrator; J. Atmos. Ocean. Tech. 28 445–452.CrossRefGoogle Scholar
  39. Rajeevan M, Rohni P, Kumar K N, Srinivasan J and Unnikrishnan C K 2012 A study of vertical cloud structure of the Indian summer monsoon using CloudSat data; Clim. Dynam. 40 637–650.CrossRefGoogle Scholar
  40. Randall D, Wood R, Bony S, Colman R, Fichefet T, Fyfe J, Kattsov V, Pitman A, Shukla J, Srinivasan J, Stouffer R, Sumi A and Tayler K 2007 Climate models and their evaluation; In: Climate Change 2007: The Scientific Basis. Contribution of working group I to the Forth Assessment Report of the Inter-governmental Panel on Climate Change (eds) Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt K B, Tignor M and Miller H L, Cambridge Univ. Press, Cambridge, United Kingdom, pp. 589–662.Google Scholar
  41. Schmetz J, Pili P, Tjemkes S, Just D, Kerkmann J, Rota S and Ratier A 2002 An introduction to Meteosat second generation (MSG); Bull. Am. Meteorol. Soc. 83 977–992.CrossRefGoogle Scholar
  42. Schumacher C and Houze Jr R A 2000 Comparison of radar data from the TRMM satellite and Kwajalein oceanic validation site; J. Appl. Meteorol. 39 2151–2164.CrossRefGoogle Scholar
  43. Schumacher C and Houze Jr R A 2006 Stratiform precipitation production over sub-Saharan Africa and the tropical East Atlantic as observed by TRMM; Quart. J. Roy. Meteorol. Soc. 132 2235–2255.CrossRefGoogle Scholar
  44. Steiner M and Houze Jr R A 1998 Sensitivity of monthly three-dimensional radar-echo characteristics to sampling frequency; J. Meteorol. Soc. Japan 76 73–95.Google Scholar
  45. Stephens G L 1994 Remote sensing of the lower atmosphere: An introduction; Oxford University Press, UK, 523p.Google Scholar
  46. Stephens G L, Vane D G, Boain R J, Mace G G, Sassen K, Wang Z, Illingworth A J, O’Connor E, Rossow W B, Durden S L, Miler S D, Austin R T, Benedetti A, Mitrescu C and CloudSat Science Team 2002 The CloudSat mission and the A-TRAIN: A new dimension to space-based observations of clouds and precipitation; Bull. Am. Meteorol. Soc. 83 1771–1790.CrossRefGoogle Scholar
  47. Stephens G L, Vane D G, Tanelli S, Im E, Durden S, Rokey M, Reinke D, Partain P, Mace G G, Austin R, L’Ecuyer T, Haynes J, Lebsock M, Suzuki K, Waliser D, Wu D, Kay J, Gettelman A, Wang Z and Marchand R 2008 CloudSat mission performance and early science after first year of operation; J. Geophys. Res. 113 D00A18, doi: 10.1029/2008JD009982.CrossRefGoogle Scholar
  48. Testud J, Bouar E L, Obligis E and Ali-Mehenni M 2000 The rain profiling algorithm applied to polarimetric weather radar; J. Atmos. Ocean. Tech. 17 332–356.CrossRefGoogle Scholar
  49. Wielicki B A, Barkstrom B R, Harrison E F, Lee R B, Smith G L and Cooper J E 1996 Clouds and the earth’s radiant energy system (CERES). An earth observing system experiment; Bull. Am. Meteorol. Soc. 77 853–868.CrossRefGoogle Scholar
  50. Winker D M, Vaughan M A, Omar A, Hu Y, Powell K A, Liu Z, Hunt W H and Young S A 2009 Overview of the CALIPSO Mission and CALIOP data processing algorithms; J. Atmos. Ocean. Tech. 26 2310–2323.CrossRefGoogle Scholar
  51. Wolff D B, Marks D A, Amitai E, Silberstein D S, Fisher B L, Tokay A, Wang J and Pippitt J L 2005 Ground validation for the Tropical Rainfall Measuring Mission (TRMM); J. Atmos. Ocean. Tech. 22 365–380.CrossRefGoogle Scholar
  52. Yuan J, Houze Jr R A and Heymsfield A 2011 Vertical structures of anvil clouds of tropical mesoscale convective systems observed by CloudSat; J. Atmos. Sci. 68 1653–1674.CrossRefGoogle Scholar
  53. Yuter S E and Houze Jr R A 1995 Three-dimensional kinematic and microphysical evolution of Florida cumulonimbus. Part II: Frequency distribution of vertical velocity, reflectivity, and differential reflectivity; Mon. Weather Rev. 123 1941–1963.CrossRefGoogle Scholar
  54. Zhang Y, Klein S, Mace G G and Boyle J 2007 Cluster analysis of tropical clouds using CloudSat data; Geophys. Res. Lett. 34 L12813, doi: 10.1029/2007GL029336.CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2013

Authors and Affiliations

  1. 1.Centre for Atmospheric and Oceanic SciencesIndian Institute of ScienceBangaloreIndia

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