Aerosol-cloud interaction inferred from MODIS satellite data and global aerosol models

We have used the MODIS satellite data and two global aerosol models to investigate the relationships be- tween aerosol optical depth (AOD) and cloud parameters that may be affected by the aerosol concentration. The relation- ships that are studied are mainly between AOD, on the one hand, and cloud cover, cloud liquid water path, and water vapour, on the other. Additionally, cloud droplet effective radius, cloud optical depth, cloud top pressure and aerosol ˚ Angstrexponent, have been analysed in a few cases. In the MODIS data we found, as in earlier studies, an enhance- ment in the cloud cover with increasing AOD. We find it likely that most of the strong increase in cloud cover with AOD, at least for AOD 0.2 can be explained by larger water uptake close to the clouds since relative humidity is higher in regions with higher cloud cover. The efficiency of the hy- groscopic growth depends on aerosol type, the hygroscopic nature of the aerosol, the relative humidity, and to some ex- tent the cloud screening. By analysing the ˚ Angstr¨ om expo- nent we find that the hygroscopic growth of the aerosol is not likely to be a main contributor to the cloud cover increase with AOD. Since the largest increase in cloud cover with

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

[2]  T. Storelvmo,et al.  Combined observational and modeling based study of the aerosol indirect effect , 2006 .

[3]  Steven Platnick,et al.  Impact of three‐dimensional radiative effects on satellite retrievals of cloud droplet sizes , 2006 .

[4]  Y. Kaufman,et al.  The effect of smoke particles on clouds and climate forcing , 1997 .

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

[6]  Brent N. Holben,et al.  An analysis of potential cloud artifacts in MODIS over ocean aerosol optical thickness products , 2005 .

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

[8]  M. Noguer,et al.  Climate change 2001: The scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change , 2002 .

[9]  R. Gunn,et al.  AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF AIR POLLUTION ON THE INITIATION OF RAIN , 1957 .

[10]  Byung-Gon Kim,et al.  Effective radius of cloud droplets by ground‐based remote sensing: Relationship to aerosol , 2003 .

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

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

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

[14]  U. Lohmann,et al.  Global indirect aerosol effects: a review , 2004 .

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

[16]  Lorraine Remer,et al.  A critical examination of the residual cloud contamination and diurnal sampling effects on MODIS estimates of aerosol over ocean , 2005, IEEE Transactions on Geoscience and Remote Sensing.

[17]  J. Norris.  On Trends and Possible Artifacts in Global Ocean Cloud Cover between 1952 and 1995 , 1999 .

[18]  Kevin E. Trenberth,et al.  Trends and variability in column-integrated atmospheric water vapor , 2005 .

[19]  E. Vermote,et al.  The MODIS Aerosol Algorithm, Products, and Validation , 2005 .

[20]  Variations in Low Cloud Cover over the United States during the Second Half of the Twentieth Century , 2004 .

[21]  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 .

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

[23]  E. Vermote,et al.  Operational remote sensing of tropospheric aerosol over land from EOS moderate resolution imaging spectroradiometer , 1997 .

[24]  Piers M. Forster,et al.  The semi‐direct aerosol effect: Impact of absorbing aerosols on marine stratocumulus , 2004 .

[25]  F. Bréon,et al.  Aerosol Effect on Cloud Droplet Size Monitored from Satellite , 2002, Science.

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

[27]  Tami C. Bond,et al.  Emissions of primary aerosol and precursor gases in the years 2000 and 1750 prescribed data-sets for AeroCom , 2006 .

[28]  Yoram J. Kaufman,et al.  Disentangling the role of microphysical and dynamical effects in determining cloud properties over the Atlantic , 2006 .

[29]  Reto Knutti,et al.  Constraints on radiative forcing and future climate change from observations and climate model ensembles , 2002, Nature.

[30]  E. Highwood,et al.  Climate response to tropospheric absorbing aerosols in an intermediate general‐circulation model , 2004 .

[31]  Joyce E. Penner,et al.  Soot and smoke aerosol may not warm climate , 2002 .

[32]  Axel Lauer,et al.  © Author(s) 2006. This work is licensed under a Creative Commons License. Atmospheric Chemistry and Physics Analysis and quantification of the diversities of aerosol life cycles , 2022 .

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

[34]  O. Boucher,et al.  Direct human influence of irrigation on atmospheric water vapour and climate , 2004 .

[35]  J. Hansen,et al.  Climate Effects of Black Carbon Aerosols in China and India , 2002, Science.

[36]  D. Tanré,et al.  Remote sensing of aerosol properties over oceans using the MODIS/EOS spectral radiances , 1997 .

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

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

[39]  H. Tuomenvirta,et al.  Trends in Nordic and Arctic Temperature Extremes and Ranges , 2000 .

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

[41]  Reto Knutti,et al.  Climate Forcing by Aerosols--a Hazy Picture , 2003, Science.

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

[43]  O. Boucher,et al.  A satellite view of aerosols in the climate system , 2002, Nature.

[44]  Dana E. Veron,et al.  First measurements of the Twomey indirect effect using ground‐based remote sensors , 2003 .

[45]  Harshvardhan,et al.  Influence of anthropogenic aerosol on cloud optical depth and albedo shown by satellite measurements and chemical transport modeling , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[46]  Sonoyo Mukai,et al.  A study of the direct and indirect effects of aerosols using global satellite data sets of aerosol and cloud parameters , 2003 .

[47]  M. Andreae,et al.  Size Matters More Than Chemistry for Cloud-Nucleating Ability of Aerosol Particles , 2006, Science.

[48]  Joyce E. Penner,et al.  Observational evidence of a change in radiative forcing due to the indirect aerosol effect , 2004, Nature.

[49]  Andrei P. Sokolov,et al.  Quantifying Uncertainties in Climate System Properties with the Use of Recent Climate Observations , 2002, Science.

[50]  T. Iversen,et al.  A scheme for process‐tagged SO4 and BC aerosols in NCAR CCM3: Validation and sensitivity to cloud processes , 2002 .

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

[52]  T. Berntsen,et al.  A global model of the coupled sulfur/oxidant chemistry in the troposphere: The sulfur cycle , 2004 .

[53]  T. Karl,et al.  Increased cloudiness in the United States during the first half of the Twentieth Century: Fact or fiction? , 1990 .

[54]  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.

[55]  Berntsen,et al.  Comparison of the radiative properties and direct radiative effect of aerosols from a global aerosol model and remote sensing data over ocean , 2007 .

[56]  A. Kirkevåg,et al.  Global direct radiative forcing by process‐parameterized aerosol optical properties , 2002 .

[57]  M. Chin,et al.  Aerosol anthropogenic component estimated from satellite data , 2005 .

[58]  G. Myhre,et al.  Uncertainties in the Radiative Forcing Due to Sulfate Aerosols , 2004 .