Rita Roberts, of the National Centre for Atmospheric Research, in Colorado, and Frederic Fabry, of McGill University in Canada, think they have found out how to do this.

• 科罗拉多州国家大气研究中心的罗伯茨和加拿大麦吉尔大学的佛伯瑞认为，他们已经知道如何做到这一点了。