Hirotaka Nakatsuka

Design and development status of the EarthCARE Cloud Profiling Radar

The Cloud Profiling Radar (CPR) for the EarthCARE mission has been jointly developed by JAXA and NICT in Japan. The CPR is a millimeter-wave radar which has a large deployable antenna and its unique feature is vertical Doppler velocity measurement capability. The Engineering Model development and testing are now ongoing and the predicted performance will be verified after a series of tests. This paper will present the latest design and development status of the EarthCARE CPR.

Development status of cloud profiling radar for EarthCARE

Global three-dimensional cloud distributions and their properties are important information to estimate the earth radiation budget more precisely. The interactions between cloud particles and aerosols are also focused to improve accuracies of climate model. In order to meet expectations of scientists developing climate models for global warming problem, European and Japanese space agencies plan to launch a satellite called EarthCARE. The Cloud Profiling Radar (CPR), which will be the first millimeter-wave Doppler radar in space, is installed on this satellite as one of main sensors to observe clouds. This paper describes the latest design and development status of EarthCARE CPR.

EarthCARE mission, overview, implementation approach, and development status

The European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) are co-operating to develop the EarthCARE satellite mission with the fundamental objective of improving the understanding of the processes involving clouds, aerosols and radiation in the Earths atmosphere in order to include them correctly and reliably in climate and numerical weather prediction models. The satellite will be placed in a Sun-Synchronous Orbit at about 400 Km altitude and14h00 mean local solar time. The payload consisting of a High Spectral Resolution UV Atmospheric LIDar (ATLID), a 94GHz Cloud Profiling Radar (CPR) with Doppler capability, a Multi-Spectral Imager (MSI) and a Broad-Band Radiometer will provide information on cloud and aerosol vertical structure of the atmosphere along the satellite track as well as information about the horizontal structures of clouds and radiant flux from sub-satellite cells. The presentation will cover the configuration of the satellite with its four instruments, the mission implementation approach, an overview of the ground segment and the overall mission development status.

The Earthcare Cloud Profiling Radar, its PFM development status (Conference Presentation)

The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is joint mission between Europe and Japan for the launch year of 2018. Mission objective is to improve scientific understanding of cloud-aerosol-radiation interactions that is one of the biggest uncertain factors for numerical climate and weather predictions. The EarthCARE spacecraft equips four instruments such as an ultra violet lidar (ATLID), a cloud profiling radar (CPR), a broadband radiometer (BBR), and a multi-spectral imager (MSI) and perform complete synergy observation to observe aerosols, clouds and their interactions simultaneously from the orbit. Japan Aerospace Exploration Agency (JAXA) is responsible for development of the CPR in this EarthCARE mission and the CPR will be the first space-borne W-band Doppler radar. The CPR is defined with minimum radar sensitivity of -35dBz (6dB better than current space-borne cloud radar, i.e. CloudSat, NASA), radiometric accuracy of 2.7 dB, and Doppler velocity measurement accuracy of less than 1.3 m/s. These specifications require highly accurate pointing technique in orbit and high power source with large antenna dish. JAXA and National Institute of Information and Communications Technology (NICT) have been jointly developed this CPR to meet these strict requirements so far and then achieved the development such as new CFRP flex-core structure, long life extended interaction klystron, low loss quasi optical feed technique, and so on. Through these development successes, CPR development phase has been progressed to critical design phase. In addition, new ground calibration technique is also being progressed for launch of EarthCARE/CPR. The unique feature of EarthCARE CPR is vertical Doppler velocity measurement capability. Vertical Doppler velocity measurement is very attractive function from the science point of view, because vertical motions of cloud particles are related with cloud microphysics and dynamics. However, from engineering point of view, Doppler measurement from satellite is quite challenging Technology. In order to maintain and ensure the CPR performance, several types of calibration data will be obtained by CPR. Overall performance of CPR is checked by Active Radar Calibrator (ARC) equipped on the ground (CPR in External Calibration mode). ARC is used to check the CPR transmitter performance (ARC in receiver mode) and receiver performance (ARC in transmitter mode) as well as overall performance (ARC in transponder mode with delay to avoid the contamination with ground echo). In Japan, the instrument industrial Critical Design Review of the CPR was completed in 2013 and it was also complemented by an Interface and Mission aspects CPR CDR, involving ESA and the EarthCARE Prime, that was completed successfully in 2015. The CPR Proto-Flight Model is currently being tested with almost completion of Proto-Flight Model integration. After handed-over to ESA planned for the beginning of 2017, the CPR will be installed onto the EarthCARE satellite with the other instruments. After that the CPR will be tested, transported to Guiana Space Center in Kourou, French Guiana and launched by a Soyuz launcher in 2018. This presentation will show the summary of the latest CPR design and CPR PFM testing status.

EarthCARE/CPR design results and PFM dvelopment status

Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) is a Japanese-European collaborative earth observation satellite mission aimed to deepen understanding of the interaction process between clouds and aerosols and their effects on the Earth’s radiation. The outcome of this mission is expected to improve the accuracy of global climate change prediction. As one of instruments for EarthCARE, the Cloud Profiling Radar (CPR) is the world’s first space-borne Doppler cloud radar jointly developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). In Japan, the critical design review of the CPR has been completed in 2013, and CPR proto-flight model was manufactured and integrated until summer in 2015. Finally, the proto-flight test have been just started. This paper describes the design results and current status of CPR proto-flight test.

The EarthCARE satellite payload

EarthCARE is ESA’s third Earth Explorer Core Mission, with JAXA providing one instrument. The mission facilitates unique data product synergies, to improve understanding of atmospheric cloud–aerosol interactions and Earth radiative balance, towards enhancing climate and numerical weather prediction models. This paper will describe the payload, consisting of two active instruments: an ATmospheric LIDar (ATLID) and a Cloud Profiling Radar (CPR), and two passive instruments: a Multi Spectral Imager (MSI) and a Broad Band Radiometer (BBR). ATLID is a UV lidar providing atmospheric echoes, with a vertical resolution of 100 m, up to 40 km altitude. Using very high spectral resolution filtering the relative contributions of particle (aerosols) and Rayleigh (molecular) back scattering will be resolved, allowing cloud and aerosol optical depth to be deduced. Particle scatter co- and cross-polarisation measurements will provide information about the cloud and aerosol particles’ physical characteristics. JAXA’s 94.05 GHz Cloud Profiling Radar operates with a pulse width of 3.3 μm and repetition frequency 6100 to 7500 Hz. The 2.5 m aperture radar will retrieve data on clouds and precipitation. Doppler shift measurements in the backscatter signal will furthermore allow inference of the vertical motion of particles to an accuracy of about 1 m/s. MSI’s 500 m pixel data will provide cloud and aerosol information and give context to the active instrument measurements for 3-D scene construction. Four solar channels and three thermal infrared channels cover 35 km on one side to 115 km on the other side of the other instrument’s observations. BBR measures reflected solar and emitted thermal radiation from the scene. To reduce uncertainty in the radiance to flux conversion, three independent view angles are observed for each scene. The combined data allows more accurate flux calculations, which can be further improved using MSI data.

EarthCARE/CPR design results and PFM performance

ESA and JAXA plan to launch a satellite called EarthCARE (Earth Clouds, Aerosols and Radiation Explorer). The Cloud Profiling Radar (CPR), which will be the first millimeter-wave Doppler radar in space, is installed on this satellite as one of main sensors to observe clouds. This paper describes the design results and PFM performance of EarthCARE CPR.

EarthCARE/CPR design and verification status

The Earth, Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is joint mission between Europe and Japan for the launch year of 2015. Mission objective is to improve scientific understanding of cloud-aerosol-radiation interactions that is one of the biggest uncertain factors for numerical climate and weather predictions. The EarthCARE spacecraft equips four instruments such as an ultra violet lidar (ATLID), a cloud profiling radar (CPR), a broadband radiometer (BBR), and a multi-spectral imager (MSI) to observe aerosols, clouds and their interactions simultaneously from the orbit. Japan aerospace exploration agency (JAXA) is responsible for development of the CPR that will be the first space-borne W-band Doppler radar. The CPR is defined with minimum radar sensitivity of -35dBz, radiometric accuracy of 2.7 dB, and Doppler velocity measurement accuracy of 1m/s. These specifications require highly accurate pointing technique in orbit and high power source with large antenna dish. JAXA and National Institute of Information and Communications Technology (NICT) have been jointly developed this CPR to meet these requirements. In addition, new ground calibration technique is also being progressed for the launch of EarthCARE/CPR. This evaluation method will also be the first use for spacecraft as well as Doppler cloud radar. This paper shows the summary of the CPR design and verification status, and activity status of development of ground calibration method with a few results of experiment using current space-borne cloud radar (CloudSat, NASA).

Development status of Japanese space-borne cloud profiling radar for EarthCARE mission

The EarthCARE mission has been jointly proposed by European and Japanese scientists with the mission objective of improving the understanding of cloud-aerosol-radiation interactions so as to include them correctly and reliably in climate and numerical weather prediction models. This EarthCARE mission has been defined as an international cooperative spacecraft mission between European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) for the planned launch year of 2013th. The EarthCARE spacecraft equips four instruments, such as a cloud profiling radar (CPR), an atmospheric backscatter lidar (ATLID), a multi-spectral imager (MSI) and a broadband radiometer (BBR) to perform very accurate synergy observation to observe cloud and aerosol vertical profiles and simultaneous radiative flux at the top of atmosphere. In this cooperation, JAXA is responsible for development of the CPR which will be the first space-borne W-band radar with Doppler measurement capability. JAXA has developed this Doppler radar for several years with Japanese National Institute of Information and Communications Technology (NICT). The last year, preliminary design was finished and then fabrication and testing have been started. This presentation shows the summary of the CPR preliminary design and reports the test status of the CPR engineering model testing.