Tibetan ice core evidence for an intensification of the East Asian jet stream since the 1870s.

The subtropical jet stream plays a significant role in the climate system and there exists evidence that it has intensified since the 1950s. However, the lack of upper-air observations before this time makes it difficult to place this trend in a longer term context. Here, we show that a Tibetan ice core's snow accumulation and dust concentration records are respectively correlated and anti-correlated with wind speeds in the jet stream over Asia as represented in both the NCEP and the 20th Century Reanalyses. This behavior is consistent with an intensification of this jet stream that began in the 1870s. [ABSTRACT FROM AUTHOR]