Remote sensing the vertical profile of cloud droplet effective radius, thermodynamic phase, and temperature

Abstract. Cloud-aerosol interaction is a key issue in the climate system, affecting the water cycle, the weather, and the total energy balance including the spatial and temporal distribution of latent heat release. Information on the vertical distribution of cloud droplet microphysics and thermodynamic phase as a function of temperature or height, can be correlated with details of the aerosol field to provide insight on how these particles are affecting cloud properties and their consequences to cloud lifetime, precipitation, water cycle, and general energy balance. Unfortunately, today's experimental methods still lack the observational tools that can characterize the true evolution of the cloud microphysical, spatial and temporal structure in the cloud droplet scale, and then link these characteristics to environmental factors and properties of the cloud condensation nuclei. Here we propose and demonstrate a new experimental approach (the cloud scanner instrument) that provides the microphysical information missed in current experiments and remote sensing options. Cloud scanner measurements can be performed from aircraft, ground, or satellite by scanning the side of the clouds from the base to the top, providing us with the unique opportunity of obtaining snapshots of the cloud droplet microphysical and thermodynamic states as a function of height and brightness temperature in clouds at several development stages. The brightness temperature profile of the cloud side can be directly associated with the thermodynamic phase of the droplets to provide information on the glaciation temperature as a function of different ambient conditions, aerosol concentration, and type. An aircraft prototype of the cloud scanner was built and flew in a field campaign in Brazil. The CLAIM-3D (3-Dimensional Cloud Aerosol Interaction Mission) satellite concept proposed here combines several techniques to simultaneously measure the vertical profile of cloud microphysics, thermodynamic phase, brightness temperature, and aerosol amount and type in the neighborhood of the clouds. The wide wavelength range, and the use of multi-angle polarization measurements proposed for this mission allow us to estimate the availability and characteristics of aerosol particles acting as cloud condensation nuclei, and their effects on the cloud microphysical structure. These results can provide unprecedented details on the response of cloud droplet microphysics to natural and anthropogenic aerosols in the size scale where the interaction really happens.

[1]  Bernard Pinty,et al.  Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview , 1998, IEEE Trans. Geosci. Remote. Sens..

[2]  E. Clothiaux,et al.  THE ATMOSPHERIC RADIATION MEASUREMENT PROGRAM CLOUD RADARS : OPERATIONAL MODES , 1999 .

[3]  Simone Tanelli,et al.  CloudSat mission: Performance and early science after the first year of operation , 2008 .

[4]  S. Martin,et al.  Relative roles of biogenic emissions and Saharan dust as ice nuclei in the Amazon basin , 2009 .

[5]  B. Albrecht.  Aerosols, Cloud Microphysics, and Fractional Cloudiness , 1989, Science.

[6]  U. Lohmann,et al.  A glaciation indirect aerosol effect caused by soot aerosols , 2002 .

[7]  Ilan Koren,et al.  Smoke and Pollution Aerosol Effect on Cloud Cover , 2006, Science.

[8]  Steven Platnick,et al.  Approximations for horizontal photon transport in cloud remote sensing problems , 2001 .

[9]  J. Comstock,et al.  Dominant role by vertical wind shear in regulating aerosol effects on deep convective clouds , 2009 .

[10]  M. Andreae.  Correlation between cloud condensation nuclei concentration and aerosol optical thickness in remote and polluted regions , 2008 .

[11]  K. Evans.  The Spherical Harmonics Discrete Ordinate Method for Three-Dimensional Atmospheric Radiative Transfer , 1998 .

[12]  D. Rosenfeld.  Aerosols, Clouds, and Climate , 2006, Science.

[13]  A. Knoll,et al.  Smoke Invigoration Versus Inhibition of Clouds over the Amazon , 2008 .

[14]  B. Lynn,et al.  Simulation of a supercell storm in clean and dirty atmosphere using weather research and forecast model with spectral bin microphysics , 2009 .

[15]  Y. Kaufman,et al.  Aerosol invigoration and restructuring of Atlantic convective clouds , 2005 .

[16]  M. King,et al.  Determination of the Optical Thickness and Effective Particle Radius of Clouds from Reflected Solar Radiation Measurements. Part II: Marine Stratocumulus Observations , 1991 .

[17]  J. Hansen,et al.  Accurate monitoring of terrestrial aerosols and total solar irradiance: Introducing the Glory mission , 2007 .

[18]  V. Ramanathan,et al.  Reduction of tropical cloudiness by soot , 2000, Science.

[19]  Roger M. Wakimoto,et al.  Radar and Atmospheric Science: A Collection of Essays in Honor of David Atlas , 2003 .

[20]  D. Rosenfeld,et al.  Aircraft Microphysical Documentation from Cloud Base to Anvils of Hailstorm Feeder Clouds in Argentina , 2006 .

[21]  Peter Pilewskie,et al.  Discrimination of ice from water in clouds by optical remote sensing , 1987 .

[22]  R. McGraw,et al.  Kinetic potential and barrier crossing: a model for warm cloud drizzle formation. , 2003, Physical review letters.

[23]  L. Kou,et al.  Refractive indices of water and ice in the 0.65- to 2.5-µm spectral range. , 1993, Applied optics.

[24]  B. Mayer,et al.  Remote sensing of stratocumulus clouds: Uncertainties and biases due to inhomogeneity , 2006 .

[25]  Ilan Koren,et al.  Measurement of the Effect of Amazon Smoke on Inhibition of Cloud Formation , 2004, Science.

[26]  Samantha Melani,et al.  CONSIDERATIONS ON DAYLIGHT OPERATION OF 1.6-VERSUS 3.7-µm CHANNEL ON NOAA AND METOP SATELLITES , 2004 .

[27]  J. Theon,et al.  Tropical rainfall measuring mission (TRMM) , 1987 .

[28]  Sally A. McFarlane,et al.  A Bayesian algorithm for the retrieval of liquid water cloud properties from microwave radiometer and millimeter radar data , 2002 .

[29]  Rosenfeld,et al.  Suppression of rain and snow by urban and industrial air pollution , 2000, Science.

[30]  Yinon Rudich,et al.  Desert dust suppressing precipitation: A possible desertification feedback loop , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[31]  A. Pokrovsky,et al.  Aerosol impact on the dynamics and microphysics of deep convective clouds , 2005 .

[32]  Olga Khersonsky,et al.  Treating clouds with a grain of salt , 2002 .

[33]  Tobias Zinner,et al.  Remote sensing of cloud sides of deep convection: towards a three-dimensional retrieval of cloud particle size profiles , 2008 .

[34]  A. Betts,et al.  Contrasting convective regimes over the Amazon: Implications for cloud electrification , 2002 .

[35]  Gerald M. Stokes,et al.  The Atmospheric Radiation Measurement Program , 2003 .

[36]  Observations of microphysics pertaining to the development of drizzle in warm, shallow cumulus clouds , 2000 .

[37]  D. Rosenfeld.  Aerosol-Cloud Interactions Control of Earth Radiation and Latent Heat Release Budgets , 2007 .

[38]  Meinrat O. Andreae,et al.  Robust relations between CCN and the vertical evolution of cloud drop size distribution in deep convective clouds , 2005 .

[39]  K. Liou,et al.  Parameterization of the scattering and absorption properties of individual ice crystals , 2000 .

[40]  S. Twomey,et al.  Simple Approximations for Calculations of Absorption in Clouds , 1980 .

[41]  A. Smirnov,et al.  AERONET-a federated instrument network and data archive for aerosol Characterization , 1998 .

[42]  Daniel Rosenfeld,et al.  Cloud Microphysical Properties, Processes, and Rainfall Estimation Opportunities , 2003 .

[43]  C. O'Dowd,et al.  Flood or Drought: How Do Aerosols Affect Precipitation? , 2008, Science.

[44]  Alexander Khain,et al.  Microphysics, Radiation and Surface Processes in the Goddard Cumulus Ensemble (GCE) Model , 2003 .

[45]  Ilan Koren,et al.  The effect of smoke, dust, and pollution aerosol on shallow cloud development over the Atlantic Ocean. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[46]  W. Cotton,et al.  Aerosol pollution impact on precipitation : a scientific review , 2009 .

[47]  Anthony B. Davis,et al.  3D Radiative Transfer in Cloudy Atmospheres , 2005 .

[48]  Yoram J. Kaufman,et al.  What does Reflection from Cloud Sides tell us about Vertical Distribution of Cloud Droplet Sizes , 2006 .

[49]  Guy Kelman,et al.  Satellite detection of severe convective storms by their retrieved vertical profiles of cloud particle effective radius and thermodynamic phase , 2008 .

[50]  Zhanqing Li,et al.  Retrieving vertical profiles of water‐cloud droplet effective radius: Algorithm modification and preliminary application , 2003 .

[51]  William L. Woodley,et al.  Deep convective clouds with sustained supercooled liquid water down to -37.5 °C , 2000, Nature.

[52]  Itamar M. Lensky,et al.  The time-space exchangeability of satellite retrieved relations between cloud top temperature and particle effective radius , 2005 .

[53]  Zhanqing Li,et al.  Estimating the vertical variation of cloud droplet effective radius using multispectral near‐infrared satellite measurements , 2002 .

[54]  Peter Pilewskie,et al.  Cloud Phase Discrimination by Reflectance Measurements near 1.6 and 2.2 , 1987 .

[55]  Anthony B. Davis,et al.  Radiative smoothing in fractal clouds , 1995 .

[56]  Itamar M. Lensky,et al.  Satellite-Based Insights into Precipitation Formation Processes in Continental and Maritime Convective Clouds , 1998 .

[57]  A. Pokrovsky,et al.  Simulating convective clouds with sustained supercooled liquid water down to −37.5°C using a spectral microphysics model , 2001 .

[58]  E. O'connor,et al.  The CloudSat mission and the A-train: a new dimension of space-based observations of clouds and precipitation , 2002 .

[59]  S. Twomey.  The Influence of Pollution on the Shortwave Albedo of Clouds , 1977 .

[60]  V. Ramanathan,et al.  Aerosols, Climate, and the Hydrological Cycle , 2001, Science.

[61]  M. King,et al.  Determination of the optical thickness and effective particle radius of clouds from reflected solar , 1990 .

[62]  Maria Cristina Facchini,et al.  The effect of physical and chemical aerosol properties on warm cloud droplet activation , 2005 .

[63]  G. Luderer,et al.  The Chisholm firestorm: observed microstructure, precipitation and lightning activity of a pyro-cumulonimbus , 2006 .

[64]  J. Hansen,et al.  Radiative forcing and climate response , 1997 .

[65]  D. Rosenfeld.  TRMM observed first direct evidence of smoke from forest fires inhibiting rainfall , 1999 .

[66]  M. Andreae,et al.  Smoking Rain Clouds over the Amazon , 2004, Science.

[67]  Y. Kaufman,et al.  Switching cloud cover and dynamical regimes from open to closed Benard cells in response to the suppression of precipitation by aerosols , 2006 .

[68]  C. Fairall,et al.  Measurement of Stratus Cloud and Drizzle Parameters in ASTEX with a K , 1995 .

[69]  Woodley,et al.  Deep convective clouds with sustained supercooled liquid water down to -37.5 degrees C , 2000, Nature.

[70]  A. Blyth,et al.  A Climatological Parameterization for Cumulus Clouds , 1991 .

[71]  Alexander Khain,et al.  The Role of Sea Spray in Cleansing Air Pollution over Ocean via Cloud Processes , 2002, Science.

[72]  W. Paul Menzel,et al.  The MODIS cloud products: algorithms and examples from Terra , 2003, IEEE Trans. Geosci. Remote. Sens..