Albedo, atmospheric solar absorption and heating rate measurements with stacked UAVs

This paper reports unique measurements of albedo, atmospheric solar absorption, and heating rates in the visible (0.4 to 0.7 µm) and broadband (0.3 to 2.8 µm) spectral regions using vertically stacked multiple lightweight autonomous unmanned aerial vehicles (UAVs). The most significant finding of this study is that when absorbing aerosols and water vapour concentrations are measured accurately and accounted for in models, and when heating rates are measured directly with stacked aircraft, the simulated clear sky heating rates are consistent with the observed broadband heating rates within experimental errors (about 15%). We conclude that there is no need to invoke anomalous or excess absorption or unknown physics in clear skies.

[1]  A. Vogelmann.  Greenhouse Effect, Atmospheric Solar Absorption and the Earth's Radiation Budget: From the Arrhenius-Langley Era to the 1990s , 2008 .

[2]  M. V. Ramana,et al.  Capturing vertical profiles of aerosols and black carbon over the Indian Ocean using autonomous unmanned aerial vehicles , 2007 .

[3]  M. V. Ramana,et al.  Warming trends in Asia amplified by brown cloud solar absorption , 2007, Nature.

[4]  M. V. Ramana,et al.  Abrupt transition from natural to anthropogenic aerosol radiative forcing: Observations at the ABC‐Maldives Climate Observatory , 2006 .

[5]  V. Ramanathan,et al.  Impact of monsoon transitions on the physical and optical properties of aerosols , 2006 .

[6]  C. Gautier,et al.  Absorption of shortwave radiation in a cloudy atmosphere: Observed and theoretical estimates during the second Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE) , 2003 .

[7]  R. Marchand,et al.  Quantifying the magnitude of anomalous solar absorption , 2003 .

[8]  F. Valero,et al.  Absorption of solar radiation by the clear and cloudy atmosphere during the Atmospheric Radiation Measurement Enhanced Shortwave Experiments (ARESE) I and II: Observations and models , 2003 .

[9]  Glenn E. Shaw,et al.  Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze , 2001 .

[10]  Igor A. Podgorny,et al.  A modeling study of the direct effect of aerosols over the tropical Indian Ocean , 2001 .

[11]  V. Ramanathan,et al.  Scale Dependence of Solar Heating Rates in Convective Cloud Systems with Implications to General Circulation Models. , 2001 .

[12]  Ibrahim Reda,et al.  Measurement of Broadband Diffuse Solar Irradiance Using Current Commercial Instrumentation with a Correction for Thermal Offset Errors , 2001 .

[13]  Akihiro Uchiyama,et al.  No evidence for solar absorption anomaly by marine water clouds through collocated aircraft radiation measurements , 2000 .

[14]  T. Eck,et al.  Accuracy assessments of aerosol optical properties retrieved from Aerosol Robotic Network (AERONET) Sun and sky radiance measurements , 2000 .

[15]  V. Ramanathan,et al.  Aerosol modulation of atmospheric and surface solar heating over the tropical Indian Ocean , 2000 .

[16]  E. Hale.  The question. , 2000, Nursing.

[17]  Zhanqing Li,et al.  Analyses of Atmospheric Radiation Measurement (ARM) program's Enhanced Shortwave Experiment (ARESE) multiple data sets for studying cloud absorption , 1999 .

[18]  Albert Arking,et al.  Bringing climate models into agreement with observations of atmospheric absorption , 1999 .

[19]  E. Clothiaux,et al.  The k-distribution method and correlated-k approximation for a shortwave radiative transfer model. , 1999 .

[20]  R. Cess,et al.  Comparison of atmospheric clear‐sky shortwave radiation models to collocated satellite and surface measurements in Canada , 1998 .

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

[22]  A. Berk,et al.  Models overestimate diffuse clear‐sky surface irradiance: A case for excess atmospheric absorption , 1998 .

[23]  Veerabhadran Ramanathan,et al.  Observational constraints on non-Lorentzian continuum effects in the near-infrared solar spectrum using ARM ARESE data , 1998 .

[24]  V. Ramanathan,et al.  Effects of cloud shape and water vapor distribution on solar absorption in the near infrared , 1998 .

[25]  W. Collins,et al.  Atmospheric Radiation Measurements Enhanced Shortwave Experiment (ARESE): Experimental and data details , 1997 .

[26]  Minghua Zhang,et al.  Absorption of solar radiation by the cloudy atmosphere: Further interpretations of collocated aircraft measurements , 1997 .

[27]  W. Collins,et al.  Atmospheric absorption during the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE) , 1997 .

[28]  E. Clothiaux,et al.  Uncertainties in modeled and measured clear‐sky surface shortwave irradiances , 1997 .

[29]  S. Kravitz,et al.  Synthetic infrared spectra. , 1997, Optics letters.

[30]  K. Trenberth,et al.  Earth's annual global mean energy budget , 1997 .

[31]  P. Francis,et al.  On the question of enhanced absorption of solar radiation by clouds , 1997 .

[32]  Albert Arking,et al.  Absorption of Solar Energy in the Atmosphere: Discrepancy Between Model and Observations , 1996, Science.

[33]  D. Randall,et al.  Mission to planet Earth: Role of clouds and radiation in climate , 1995 .

[34]  P. Pilewskie,et al.  Direct Observations of Excess Solar Absorption by Clouds , 1995, Science.

[35]  C. H. Whitlock,et al.  Absorption of Solar Radiation by Clouds: Observations Versus Models , 1995, Science.

[36]  V. Ramanathan,et al.  Warm Pool Heat Budget and Shortwave Cloud Forcing: A Missing Physics? , 1995, Science.

[37]  Bruce R. Barkstrom,et al.  An efficient algorithm for choosing scattering directions in Monte Carlo work with arbitrary phase functions , 1995 .

[38]  R. Saunders,et al.  A Comparison of Measured and Modeled Broadband Fluxes from Aircraft Data during the ICE '89 Field Experiment , 1992 .

[39]  L. Bannehr,et al.  Preprocessing of Airborne Pyranometer Data , 1991 .

[40]  Si-Chee Tsay,et al.  On the cloud absorption anomaly , 1990 .

[41]  Patrick Minnis,et al.  Comparison of regional clear-sky albedos inferred from satellite-observations and model computations , 1986 .

[42]  L. J. Cox.  Optical Properties of the Atmosphere , 1979 .

[43]  D. Murcray.  Optical Properties of the Atmosphere , 1968 .

[44]  S. Fritz,et al.  Solar Radiant Energy and its Modification by the Earth and its Atmosphere , 1951 .