This satellite covers the whole of Africa and goes back as far as 1984, and that's important, because if you know how many times a place has had a drought in the last 30 years, you can make a pretty good estimate what the chances are of drought in the future, and that means that you can put a price tag on the risk of drought.
这颗卫星覆盖了整个非洲， 数据最远可追溯到1984年， 而这一点很重要，因为如果你知道 一个地方在过去30年间 发生了多少次旱灾， 那么你就可以很好的估计 这个地方在未来发生旱灾的可能性， 这也就意味着 你可以对旱灾的风险进行标价。