A、It involves more than eight low-orbit satellites. B、It has successfully helped predict the intensity of hurricanes in 2017. C、

There have been many improvements in how weather experts predict the path of hurricanes, powerful storms that form in the ocean. However, forecasters still struggle when trying to estimate one quality of a coming storm：its intensity. Intensity measurements would help people prepare for flooding and deadly winds. In 2017, the US government’s National Hurricane Centre reported that it had failed to correctly predict the sudden intensification of the 2016 hurricane called Matthew. That storm strengthened very quickly, with winds reaching up to 270 kilometers per hour. It caused major destruction in the Caribbean, including killing more than 1000 people in Haiti, according to Reuters. Scientists say there are several scientific models for predicting hurricane intensity, but they are all of limited use. The current science of tracking a storm’s path depends heavily on information about conditions on its edges. But, intensity is based on what is happening in the middle of it. Generally, measurements are taken one of three ways. Sometimes researchers fly a “hurricane hunter” aircraft into the storm. Other times, they use a device called a weather buoy to measure wind speeds as a storm passes over. Or, they get information from satellites. One project to gather more information to predict intensity is the Cyclone Global Navigation Satellite System, or CYGNSS for short. CYGNSS is a group of eight low-orbit satellites. The American space agency, NASA launched it in 2016.
    Earlier satellites had trouble measuring ocean surface winds at the centre of storms. Heavy rain at the centre often weakened their signals, NASA officials said.
    Christopher Ruf is a lead investigator with CYGNSS and a climate science professor at the University of Michigan. He noted, "For storms that are changing really quickly, you could miss something like rapid intensification. " NASA designed CYGNSS to measure surface winds in and near the centre of tropical storm systems. Researchers said that having more satellites means they can pass over the storms more often. And the low-orbit satellites are closer to the storms. So, experts get more real-time information to use for predicting intensity. At present, researchers are focusing on the 2017 season when hurricanes severely affected Texas, Florida and Puerto Rico. Storms caused hundreds of billions of dollars in damage. And researchers are re-examining information gathered from CYGNSS to see how it affected the quality of the forecasts and how it can be better used to predict intensity.
    CYGNSS could be fully operational next year, researchers said.
    23. Which quality of a coming storm bothers forecasters?
    24. What do scientists say about current scientific models for predicting hurricane intensity?
    25. What can we learn about CYGNSS?