16:00 〜 16:15
[ACG41-27] Integrated analysis of spaceborne cloud and precipitation radars using the EarthCARE - GPM coincidence dataset
キーワード：EarthCARE、GPM、衛星搭載レーダ
The Global Precipitation Measurement (GPM) Dual-Frequency Precipitation Radar (DPR) (Ku- and Ka-band) provides vertical profiles of hydrometeors under moderate to heavy precipitation conditions across the tropics and mid-latitudes (Hou et al. 2014, Skofronick-Jackson et al. 2017). Owing to its unique asynchronous orbit of the GPM Core Observatory, its orbital ground tracks intersect the orbit of many other sun-synchronous satellites. The CloudSat - GPM coincidence dataset (CSATGPM; Turk et al. 2021) provides "pseudo three-frequency" radar profiles from near-coincident observations. This dataset focuses on intersections with CloudSat’s W-band cloud radar, which is highly effective in observing clouds and light precipitation. In addition, simultaneous observations from CloudSat and the Tropical Rainfall Measuring Mission (TRMM; Kummerow et al. 1998), the predecessor of GPM, are also available in the CSATTRMM dataset (Turk et al. 2021). This dataset includes a larger number of cases compared to CSATGPM, as it covers the period before CloudSat transitioned to daytime-only operations in 2011. Both datasets have been widely used in scientific studies, including research on cold-season precipitation, ice microphysics, and light rainfall.
The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite (Illingworth et al., 2015; Wehr et al., 2023), launched in May 2024, is equipped with four sensors that employ different observation methods: radar, lidar, imager, and radiometer. Particularly, the Cloud-Profiling Radar (CPR), developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT) continues the cloud and precipitation observations performed by the CloudSat while introducing the world’s first measurements of vertical cloud motion from space. Based on the CSATGPM dataset, we are constructing a coincident observation dataset for the EarthCARE-period.
The two satellites recorded several hundred coincident observation events per month, with approximately one-third of these events detecting precipitation on both satellites. An examination of the vertical profiles of radar reflectivity revealed that while the DPR detected large raindrops and snow particles in advanced stages of growth, the CPR captured detailed features within clouds at higher altitudes. In stratiform precipitation cases, Doppler velocity observations from the CPR showed slower downward motion at altitudes above the bright band detected by the DPR, and faster downward motion at lower altitudes. In W-band radar observation, rainfall-induced attenuation is significant, making it difficult to measure moderate to high rainfall intensities with CloudSat. However, Doppler velocity observations, which extract phase information from the signal, are less affected by attenuation compared to radar reflectivity. In this study, we compared the raindrop fall velocities from the Doppler velocity measurements of EarthCARE CPR with the radar reflectivity of the DPR, which is less affected by attenuation than W-band radar. The results showed a positive correlation between the two, suggesting that Doppler velocity information could be useful for attenuation correction in W-band radar and for more advanced analyses of rainfall properties.
The combination of 13-channel (10–183 GHz) GMI with active W-band radar observations is also useful for algorithm development and evaluation, sensitivity studies of snow and light rain, cloud process studies, and radiative transfer simulations. Preliminary results from simultaneous observations with EarthCARE/CPR and GMI radiometers will also be presented.
The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite (Illingworth et al., 2015; Wehr et al., 2023), launched in May 2024, is equipped with four sensors that employ different observation methods: radar, lidar, imager, and radiometer. Particularly, the Cloud-Profiling Radar (CPR), developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT) continues the cloud and precipitation observations performed by the CloudSat while introducing the world’s first measurements of vertical cloud motion from space. Based on the CSATGPM dataset, we are constructing a coincident observation dataset for the EarthCARE-period.
The two satellites recorded several hundred coincident observation events per month, with approximately one-third of these events detecting precipitation on both satellites. An examination of the vertical profiles of radar reflectivity revealed that while the DPR detected large raindrops and snow particles in advanced stages of growth, the CPR captured detailed features within clouds at higher altitudes. In stratiform precipitation cases, Doppler velocity observations from the CPR showed slower downward motion at altitudes above the bright band detected by the DPR, and faster downward motion at lower altitudes. In W-band radar observation, rainfall-induced attenuation is significant, making it difficult to measure moderate to high rainfall intensities with CloudSat. However, Doppler velocity observations, which extract phase information from the signal, are less affected by attenuation compared to radar reflectivity. In this study, we compared the raindrop fall velocities from the Doppler velocity measurements of EarthCARE CPR with the radar reflectivity of the DPR, which is less affected by attenuation than W-band radar. The results showed a positive correlation between the two, suggesting that Doppler velocity information could be useful for attenuation correction in W-band radar and for more advanced analyses of rainfall properties.
The combination of 13-channel (10–183 GHz) GMI with active W-band radar observations is also useful for algorithm development and evaluation, sensitivity studies of snow and light rain, cloud process studies, and radiative transfer simulations. Preliminary results from simultaneous observations with EarthCARE/CPR and GMI radiometers will also be presented.