EarthCARE (Earth Explorer 6)

EarthCARE [ESA]

EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is a joint European-Japanese mission addressing the need for a better understanding of the interactions between cloud, radiative and aerosol processes that play a role in climate regulation.

The EarthCARE mission aims to improve the representation and understanding of the Earth's radiative balance in climate and numerical weather forecast models by acquiring vertical profiles of clouds and aerosols, as well as the radiances at the top of the atmosphere.

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

• Vertical profiles of natural and anthropogenic aerosols on a global scale, their radiative properties and interaction with clouds.
• 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.
• The combination of the retrieved aerosols and cloud properties to derive the profile of atmospheric radiative heating and cooling.

To realize the measurement goals and meet the scientific objectives, it is proposed to launch 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). 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 active-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.

EarthCare will carry following instruments:

• Backscatter Lidar (ATLID) - ESA High-spectral resolution and depolarization
• 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)

The contract with EADS Astrium was signed in 2008 at an initial value of 263 million euros, with a launch scheduled for 2013. The development of ATLID was much delayed due to the ADM-Aeolus LIDAR problems, so that launch has slipped to late 2018 and then to 2022.

EarthCare is provided by ESA and is baselined for a launch on a Soyuz-ST-B Fregat-MT booster from Kourou. Among the alternatives considered is the Indian PSLV vehicle. In 2019, a Soyuz-ST-B Fregat-MT was contracted. In October 2022 a Vega-C was selected for launch.