Clouds, climate, challengesHerman RusschenbergRemote Sensing of the Atmosphere
Earth-atmosphere energy balance
The radiation balance: a status quoSolar energyNo atmosphereToo cold to live inGreenhousegasesToo warm to live inCooling c...
Clouds and climateClouds scatter lightClouds absorb heatEvaporation coolsCondensation warmsCooling Warming
A bit about cloud formationCondensationlevelNo aerosols A few aerosols Many aerosolsMoist air parcelsClouds
rainfall formationLarge droplets:rainfallMore aerosolsDelayed rainfallLonger cloud lifetimeSustained impacton radiation
DirectwarmingduetoCO2ResponseoftheearthAdditionalwarmingGlobal warming: state of the art
Short wave fluxes Long wave fluxesNumber concentrationLiquid water contentOptical depth = total extinction of radiation du...
Example of flux calculations
Neg. FeedbackPos. FeedbackPresentPerturbed FutureStrong Pos. FeedbackPossible cloud responses to warming
Greenland melt, July 2012
Bennartz et al, 2013, NatureImpact of thin low level clouds onsurface temperature
How much light reaches the earth?How much is reflected into space?How much heat leaves the earth?How much water condenses ...
50 km50kmClimate gridWhy are clouds so difficult?
Complexity of the problemLarge variety of cloud typesGlobal information neededA large range of temporal and spatial scales...
How to solve this problem?Models Observations
Cesar ObservatoryDelft University of Technology, KNMI, Wageningen University and ResearchUtrecht University, RIVM, ECN, TN...
Observation of light rain with different instrumentslidar radartimeheightWhy multi-sensor strategies?short wavelength long...
1.  Cloud thickness2.  Liquid water content3.  Droplet size4.  Number concentration5.  Vertical profileWhat do we have to ...
Assume a cloud modelCloud baseCloud topHExpected response of radarExpected response of lidarNumber of dropletsWater content
radar lidar radiometerInside stratocumulusRadar reflection [dBZ]Total amount of water [g/m^2]Time [utc]
estimate cloud parametersDroplet concentration Profile particle sizeCourtesy: Christine Brandau
Extinction Optical thicknessradiative properties
Questions•  Can we use radiation measurements toevaluate cloud retrievals?•  What’s the impact of the assumed verticalclou...
Evaluation with radiative closure•  retrieval of cloud microphysics•  calculate the surface radiation•  compare with surfa...
Models of the vertical cloud structureThree models fordifferent verticalvariations within thecloud1.  Homogeneous Mixing2....
The 3 vertical cloudmodels canreproduce theradiation at surfacewith small biasesSurface radiation closure
Impact of the vertical cloud structureThree models for differentvertical variations within thecloud1.  Homogeneous Mixing2...
Way of the future: integrationspace, ground, air, modelsIce cloudsWater cloudsMixed phase cloudsdrizzlerainfallEnergy flux...
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Presentation Russchenberg - Clouds, Climate, Challenges

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10/04/2013 TU Delft Climate Institute Symposium: Do clouds change in a warming climate?

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Presentation Russchenberg - Clouds, Climate, Challenges

  1. 1. Clouds, climate, challengesHerman RusschenbergRemote Sensing of the Atmosphere
  2. 2. Earth-atmosphere energy balance
  3. 3. The radiation balance: a status quoSolar energyNo atmosphereToo cold to live inGreenhousegasesToo warm to live inCooling cloudsNice in the shadeheight-20 +24 +14
  4. 4. Clouds and climateClouds scatter lightClouds absorb heatEvaporation coolsCondensation warmsCooling Warming
  5. 5. A bit about cloud formationCondensationlevelNo aerosols A few aerosols Many aerosolsMoist air parcelsClouds
  6. 6. rainfall formationLarge droplets:rainfallMore aerosolsDelayed rainfallLonger cloud lifetimeSustained impacton radiation
  7. 7. DirectwarmingduetoCO2ResponseoftheearthAdditionalwarmingGlobal warming: state of the art
  8. 8. Short wave fluxes Long wave fluxesNumber concentrationLiquid water contentOptical depth = total extinction of radiation due to absorption and scattering
  9. 9. Example of flux calculations
  10. 10. Neg. FeedbackPos. FeedbackPresentPerturbed FutureStrong Pos. FeedbackPossible cloud responses to warming
  11. 11. Greenland melt, July 2012
  12. 12. Bennartz et al, 2013, NatureImpact of thin low level clouds onsurface temperature
  13. 13. How much light reaches the earth?How much is reflected into space?How much heat leaves the earth?How much water condenses or evaporates?How much water precipitates?The cloud questions
  14. 14. 50 km50kmClimate gridWhy are clouds so difficult?
  15. 15. Complexity of the problemLarge variety of cloud typesGlobal information neededA large range of temporal and spatial scalesA multitude of different physical parameters
  16. 16. How to solve this problem?Models Observations
  17. 17. Cesar ObservatoryDelft University of Technology, KNMI, Wageningen University and ResearchUtrecht University, RIVM, ECN, TNO , European Space AgencyGroeten uit Cabauw
  18. 18. Observation of light rain with different instrumentslidar radartimeheightWhy multi-sensor strategies?short wavelength long wavelength
  19. 19. 1.  Cloud thickness2.  Liquid water content3.  Droplet size4.  Number concentration5.  Vertical profileWhat do we have to know?Case study: water clouds
  20. 20. Assume a cloud modelCloud baseCloud topHExpected response of radarExpected response of lidarNumber of dropletsWater content
  21. 21. radar lidar radiometerInside stratocumulusRadar reflection [dBZ]Total amount of water [g/m^2]Time [utc]
  22. 22. estimate cloud parametersDroplet concentration Profile particle sizeCourtesy: Christine Brandau
  23. 23. Extinction Optical thicknessradiative properties
  24. 24. Questions•  Can we use radiation measurements toevaluate cloud retrievals?•  What’s the impact of the assumed verticalcloud profiles on radiation?
  25. 25. Evaluation with radiative closure•  retrieval of cloud microphysics•  calculate the surface radiation•  compare with surface radiation measurements•  ARM mobile facility, Germany, 2007•  Cloud radar, ceilometer, microwave radiometer•  Pyranometer surface irradiance
  26. 26. Models of the vertical cloud structureThree models fordifferent verticalvariations within thecloud1.  Homogeneous Mixing2.  Scaled-AdiabaticStratified3. Vertically Uniform
  27. 27. The 3 vertical cloudmodels canreproduce theradiation at surfacewith small biasesSurface radiation closure
  28. 28. Impact of the vertical cloud structureThree models for differentvertical variations within thecloud1.  Homogeneous Mixing2.  Scaled-Adiabatic Stratified3. Vertically Uniform
  29. 29. Way of the future: integrationspace, ground, air, modelsIce cloudsWater cloudsMixed phase cloudsdrizzlerainfallEnergy fluxes, evaporationWater balanceAerosolsWater vapourTrace gasesradiation

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