BEIJING, Nov. 16 (INP): China will launch four Fengyun satellites from 2018 to 2021, officials of Aerospace Science and Technology Corporation said here on Thursday. By then, the four satellites will establish a complete network with comprehensive observation ability, said Zhou Xubin, deputy director of the 509th Research Institute of Shanghai Academy of Spaceflight Technology. According to him, global observation will be carried out every four hours, and the update interval of the satellite observation data will also be shortened to four hours from six. In addition, the efficiency of meteorological disaster monitoring will be doubled, increasing the forecast accuracy by 3 percent. As a result, it will be easier to forecast the short and severe weather conditions such as storms and strong convection weather. INP/J/AJ