The annual precipitation of the region this year is higher than that of last year.

今年该地区的年降水量比去年高。

For example, the U.S. west coast receives 30 to 50 percent of its annual precipitation from atmospheric rivers.

例如，美国西海岸每年30%到50%的降水来自大气河流。

Which of course are both technically considered deserts as they receive far less than the 250 millimeters of annual precipitation to be considered one.

当然，严格来说，这两个地区都被认为是沙漠，因为它们的年降水量远远低于 250 毫米。

Estimates predict that places as far away as the Sierra Nevadas could see a 50% decrease in annual precipitation as a result of this event.

据估计，即使像在内华达山脉这么远的地方，每年的降水量也会因此减少50%。

Although it's extremely dry here, with the annual evaporation being more than 60 times that of the annual precipitation, the stable water source ensures a sustainable water supply to the spring.

尽管这里极为干旱，年蒸发量达到年降水量的60倍以上，稳定的水源依然可以持续带来补给。