Transition to Mission Operation Phase and Release of Level 1 Product of Cloud Profiling Radar (CPR) onboard Earth Cloud Aerosol and Radiation Explorer (EarthCARE) “Hakuryu”

The CPR has continued observations since June 2024. This document presents examples of the CPR Level 1 Product from November 7, 2024. Figure 1 shows an orbit of one complete rotation of The EarthCARE satellite "Hakuryu". The EarthCARE satellite "Hakuryu" orbits the Earth approximately 16 times a day, with each orbit taking approximately 90 minutes. Figure 2 shows the vertical distribution of the radar reflectivity and Figure 3 shows the vertical distribution of Doppler velocity, along with the orbit in Figure 1. In Figures 2 and 3, each orbit is divided into eight scenes, each labeled with a letter from A to H.

The CPR transmits radio waves from space to the Earth and receives the waves that bounce back after hitting cloud particles and raindrops in the sky. The radar reflectivity (Figure 2) represents the strength of these “bounced radio waves”. Higher values mean that there are more cloud droplets or raindrops in the sky. These figures show that various clouds around the globe are observed by the CPR.

Doppler velocity (Figure 3) is the vertical motion of cloud particles or raindrops measured based on the Doppler effect. The Doppler effect is famously known as the change in pitch of the sound of an ambulance as it passes by. In the figure, the blue indicates the downward increase in Doppler velocity and corresponds to the fast-falling speed of the raindrops.

The cloud and precipitation process, in which cloud droplets grow into rain, plays an important role in numerical models that predict heavy rainfall and future climates. It is expected that observations of different cloud regions by the CPR will help us understand the mechanism by which cloud droplets grow into rain and improve the cloud and precipitation processes in the numerical model, thereby improving the accuracy of predictions. In addition, the effect of clouds on the climate system is greatly influenced by factors such as cloud height, overlapping patterns, and cloud type. Therefore, using the four types of sensors of the EarthCARE satellite "Hakuryu" with different observation methods to measure vertical distributions of clouds, including their vertical motions on a global scale, will contribute to elucidating the mechanism by which clouds affect climate change.