Abstract
We question the correlation between vertical velocity (w) on the one hand and the occurrence of convective plumes in lidar reflectivity (i.e. range corrected backscatter signal Pz 2) and depolarization ratio (Δ) on the other hand in the convective boundary layer (CBL). Thermal vertical motion is directly investigated using vertical velocities measured by a ground-based Doppler lidar operating at 2 μm. This lidar provides also simultaneous measurements of lidar reflectivity. In addition, a second lidar 200 m away provides reflectivities at 0.53 and 1 μm and depolarization ratio at 0.53 μm. The time series from the two lidars are analyzed in terms of linear correlation coefficient (ρ). The main result is that the plume-like structures provided by lidar reflectivity within the CBL as well as the CBL height are not a clear signature of updrafts. It is shown that the lidar reflectivity within the CBL is frequently anti-correlated (ρ (w, Pz 2 )) with the vertical velocity. On the contrary, the correlation coefficient between the depolarization ratio and the vertical velocity ρ (w, Δ ) is always positive, showing that the depolarization ratio is a fair tracer of updrafts. The importance of relative humidity on the correlation coefficient is discussed.
Similar content being viewed by others
References
Atlas D, Walter B, Chou SH and Sheu PJ (1986). The structure of the unstable marine boundary layer viewed by lidar and aircraft observations. J Atmos Sci 43: 1301–1318
Ayotte KW, Sullivan PS, Dndrén A, Doney SC, Holstlag AAM, Large WG, McWillimas JC, Moeng C-H, Otte MJ, Tribbia JJ and Wyngaard JC (1996). An evaluation of neutral and convective planetary boundary-layer parameterizations relative to large eddy simulations. Boundary-Layer Meteorol 79: 131–175
Boers R, Eloranta EW, Coulter RL (1984) Lidar observations of mixed layer dynamics: tests of parameterized entrainment models of mixed layer growth rate. J Clim Appl Meteor 23:247–266
Bruneau D, Le Rille O, Pelon J (2000) Wind velocity and backscatter measurements at 2 μm with the heterodyne detection lidar EMIL. Proceedings of the 20th ILRC, Vichy, France, pp 97–100
Chazette P, Randriamiarisoa H, Sanak J, Couvert P and Flamant C (2005). Optical properties of urban aerosol from airborne and ground-based in situ measurements performed during the Etude et Simulation de la Qualité de l’air en Ile de France (ESQUIF) program. J Geophys Res 110: D02206, doi: 10.1029/2004JD004810.
Crum TD, Stull RB and Eloranta EW (1987). Coincident lidar and aircraft observations of entrainment into thermals and mixed layers. J Clim Appl Meteorol 26: 774–788
D’Almeida GA, Koepke P, Shettle PE (1991) Atmospheric aerosols: global climatology and radiative characteristics. Deepak Publications, Hampton, 561 pp
Dubovik O and King MD (2000). A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements. J Geophys Res 105: 20673–20696
Dupont E, Pelon J and Flamant C (1994). Study of the moist convective boundary layer structure by backscattering lidar. Boundary-Layer Meteorol 69: 1–25
Fitzgerald JW (1989). Model of the aerosol extinction profile in a well-mixed marine boundary layer. Appl Opt 28: 3534–3538
Frehlich R, Hannon SM and Henderson SW (1998). Coherent Doppler Lidar measurements of wind field statistics. Boundary-Layer Meteorol 86: 233–256
Gibert F, Flamant PH, Bruneau D and Loth C (2006). Two-micrometer heterodyne differential absorption Lidar measurements of the atmospheric CO2 mixing ratio in the boundary layer. Appl Opt 45: 4448–4458
Grossman RL (1984) Bivariate conditional sampling of moisture flux over a tropical ocean. J Atmos Sci 41:3238–3253
Hänel G (1976). The properties of atmospheric aerosol particles as functions of the Relative humidity at thermodynamic equilibrium with the surrounding moist air. Adv Geophys 19: 73–188
Holben BN, Eck FT, Slutsker I, Tanré D, Buis JP, Setzer A, Vermote E, Reagan JA, Kaufman YJ, Nakajima T, Lavenu F, Jankowiak I and Smirnov A (1998). AERONET— a federated instrument network and data archive for aerosol characterization. Remote Sens Environ 66: 1–16
Kaimal JC, Wyngaard JC, Haugen DA, Coté OR, Izumi Y, Caughey SJ and Readings CJ (1976). Turbulence structure in the convective boundary layer. J Atmos Sci 33: 2152–2169
Kiemle C, Kästner M and Ehret G (1995). The convective boundary layer structure from lidar and radiosonde measurements during the EFEDA ’91 Campaign. J Atmos Ocean Technologic 12: 771–782
Kiemle C, Ehret G, Davis KJ, Lenschow DH and Oncley SP (1998). Airborne water vapor differential absorption lidar studies of the convective boundary layer. In: PLanet, EJ, Federovich, EE, Viegas, DX, and Wyngaard, JC (eds) Buoyant convection in geophysical flows, pp 207–238. Kluwer Academic Publishers, Dordrecht
Kunkel KE, Eloranta EW and Shipley ST (1977). Lidar observations of the convective boundary layer. J App Meteorol 16: 1306–1311
Lenschow DH and Stephens PL (1980). The role of thermals in the convective boundary layer. Boundary-Layer Meteorol 19: 509–532
Loth C, Cuesta J Flamant PH (2004) TReSS: a transportable remote sensing station for atmospheric research and satellite validation. Proceedings of the 22nd ILRC, vol 1, Matera, Italy, pp 41–44
Mätzler C (2002) MATLAB functions for Mie scattering and absorption, version 2—group of 5’, IAP Research Report No. 2002-11.
Marsik FJ, Fischdr KW, McDonald TD and Samson FJ (1995). Comparisons of methods for estimating mixing height used during the 1992 Atlanta field intensive. J Appl Meteorol 34: 1802–1814
McNeil WR and Carswell AI (1975). Lidar polarization studies of the troposphere. Appl. Opt 14: 2158–2168
Melfi SH, Spinhirne JD and Chou S-H (1985). Lidar observations of vertically organized convection in the planetary boundary layer over the ocean. J Clim Appl Meteorol 24: 806–821
Menut L, Flamant C, Pelon J and Flamant PH (1999). Urban boundary layer height determination from Lidar measurements over the Paris area. Appl Opt 38: 945–954
Moeng C-H (1998). Parameterizations of the convective boundary layer in atmospheric models. In: PLanet, EJ, Federovich, EE, Viegas, DX and Wygaard, JC (eds) Buoyant convection in geophysical flows, pp 291–311. Kluwer Academinc Publishers, Dordrecht
Murayama T, Furushima M, Oda A, Iwasaka N and Kai K (1996). Depolarization ratio measurements in the atmospheric boundary layer by lidar in Tokyo. J Meteorol Soc of Japan 74(4): 571–578
Randriamiarisoa H, Chazette P, Couvert P and Sanak J (2005). Relative humidity impact on aerosol parameters in a Paris suburban area. Atmos Chem Phys Discuss 5: 8091–8147
Rechou A and Durand P (1997). Conditional sampling and scale analysis of the marine atmospheric mixed layer—SOFIA experiment. Boundary-Layer Meteorol 82: 81–104
Rye BJ and Hardesty RM (1993). Discrete spectral peak estimation in incoherent backscatter heterodyne lidar. I: spectral accumulation and the Cramer-Rao lower bound. IEEE Trans Geos Rem Sens 31: 16
Rye BJ and Hardesty RM (1997). Estimate optimisation parameters for incoherent backscatter heterodyne lidar. Appl Opt 36: 9425–9436
Stull RB (1988) An introduction to boundary layer meteorology. Springer, New York
Wandiger U, Linné H, Bösenberg J, Zeromskis E, Althausen D, Müller D (2004) Turbulent aerosol fluxes determined from combined observations with Doppler wind and Raman aerosol Lidar. Proceedings of the 22nd ILRC, vol 2, Matera, Italy, pp 743–746
Wilczak JM and Tillman JE (1980). The three-dimensional structure of convection in the atmospheric surface layer. J Atmos Sci 37: 2424–2443
Yano J-I, Redelsperger J-L, Guichard F and Bechtold P (2005). Mode decomposition as a methodology for developing convective-scale representations in global models. Quart J Roy Meteorol Soc 131: 2313–2336
Young GS (1988). Turbulence structure of the convective boundary layer. Part II: Phoenix 78 Aircraft observations of thermals and their environment. J Atmos Sci 45: 727–735
Author information
Authors and Affiliations
Corresponding author
Additional information
An erratum to this article can be found at http://dx.doi.org/10.1007/s10546-007-9223-4
Rights and permissions
About this article
Cite this article
Gibert, F., Cuesta, J., Yano, JI. et al. On the Correlation between Convective Plume Updrafts and Downdrafts, Lidar Reflectivity and Depolarization Ratio. Boundary-Layer Meteorol 125, 553–573 (2007). https://doi.org/10.1007/s10546-007-9205-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10546-007-9205-6