衛星捕捉到史無前例的雲影像

A groundbreaking image of a storm cloud's interior has been released by the European and Japanese space agencies. Captured by their Earthcare satellite using a Doppler radar, the image reveals the density of ice, snow, and rain within the cloud, as well as the speed at which these particles are falling to Earth. Launched in May, the Earthcare mission aims to enhance our understanding of how clouds influence the climate. The €850m (£725m) spacecraft's observations are also expected to improve weather forecasts. Typically, such images are obtained by research planes or ground installations, but not from space. Dr. Robin Hogan, a mission scientist from the European Centre for Medium-Range Weather Forecasts, expressed his excitement over the first radar images from Earthcare. He noted that for the first time, they can measure the fall speeds of ice crystals, raindrops, and snowflakes globally, not just at a few ground-based radar stations. The sample cloud was observed over the Pacific Ocean, just east of Japan, on 13 June. The image shows where different phases of water are located within the cloud. Larger particles are concentrated in the center, while velocity measurements indicate that ice crystals and snowflakes are either suspended high up or falling slowly. A clear boundary at an altitude of about 5km marks where ice and snow melt to form water droplets that then fall as rain. By analyzing the density, size, and movement of these particles, scientists hope to gain deeper insights into the physics driving cloud formation and behavior. One key area of interest is the role clouds play in a warming world. Some low-level clouds cool the planet by reflecting sunlight back into space, while others at high altitudes act like a blanket, trapping the Sun's energy. The Earthcare mission aims to determine the balance between these effects. This is a significant uncertainty in the computer models used to predict how the climate will respond to rising levels of greenhouse gases. Dr. Hogan emphasized that this is just the beginning. Three other instruments on Earthcare are being activated one by one, and together with the radar, they will help uncover the mysteries of clouds and their role in the climate system. Many members of the Earthcare team, including Dr. Hogan, have been preparing for the satellite's launch for over 20 years, making the arrival of the data an incredibly exciting moment for them.