EarthCARE

EarthCARE

Scientific Background

EarthCARE observations will lead to more reliable climate predictions and better weather forecasts through the improved representation of processes involving clouds, aerosol and radiation. Aerosols control cloud properties, clouds control the production of precipitation and vigorous convection influences stratospheric humidity.

• Cloud feedbacks are the main cause of the uncertainty in predictions of future climate.
• Correct representation of clouds – aerosol – radiation processes in models (NWP and climate) is needed. Current knowledge of the global profiles of aerosol and cloud properties is far too limited.
• Required profiles are provided by High Spectral Resolution lidar and Doppler cloud radar embarked upon the same satellite.
• Active instruments together with a multi-spectral imager and a broadband radiometer constrain radiative flux profiles to
  10 Wm^-2.

	EarthCARE concept

EarthCARE has been defined with the specific scientific objectives of quantifying cloud-aerosol-radiation interactions so they may be included correctly in climate and numerical weather forecasting models to provide:

• Vertical distribution of atmospheric liquid water and ice on a global scale, their transport by clouds and radiative impact.
• Cloud overlap in the vertical, cloud-precipitation interactions and the characteristics of vertical motion within clouds.
• Vertical profiles of natural and anthropogenic aerosols on a global scale, their radiative properties and interaction with clouds.
• The combination of the retrieved aerosols and cloud properties to derive the profile of atmospheric radiative heating and cooling.

To realise the measurement goals and meet the scientific objectives, a single platform with a payload of two active sounders (lidar and radar) and two complementary passive instruments (multi-spectral imager and a broadband radiometer) will be launched into a polar Sun-synchronous afternoon orbit. The two active instruments will provide vertical profiles of cloud and aerosol parameters. The multi-spectral imager will enable different cloud types and aerosols to be distinguished and will provide the meteorological/optical context of the actively sampled profiles. The radiometer will provide broadband radiances at the top of the atmosphere that will serve as a consistency test of the retrievals of cloud radiative properties from the active instruments.
 
 
Mission elements and products

Space segment

• Backscatter Lidar (ATLID) - ESA High-spectral resolution and depolarisation
• Cloud Profiling Radar (CPR) - JAXA/NICT -36 dBZ sensitivity, 500 m vertical range, Doppler
• Multi-Spectral Imager (MSI) - ESA 7 channels, 150 km swath, 500 m pixel
• Broadband Radiometer (BBR) - ESA 2 channels, 3 views (nadir, fore and aft)

Generic configuration with data distribution to Japan
 
 
Products

Properties of cloud fields:

• Cloud boundaries (top and base height) including multi-layer clouds.
• Height resolved fractional cloud cover and cloud overlap.
• The occurrence of ice and liquid and of super-cooled cloud layers.
• Vertical profiles of ice water content and effective ice particle size and shape.
• Vertical profiles of liquid water content and effective droplet size.
• Small scale (1km or less) fluctuations in these cloud properties.

Vertical velocities to characterise cloud convective motions and ice sedimentation.

Drizzle rain rates and estimates of heavier rainfall rates.

Properties of aerosol layers:

• The occurrence of aerosols layers, their profile of extinction coefficients and boundary layer height.
• The presence of absorbing and non-absorbing aerosols from anthropogenic or natural sources.

 
 
System Concept
 
 

mass/power 1300 kg / 1100 W Data rate up to 1500 kbit/s Orbit Sun-synchronous, DN 10:30 Height 450 km Lifetime 2 (+1) years Launcher PSLV, DNEPR or SOYUZ

 
 
Last update: 20 August 2009