 In a paper published in 2006 with Brian Soden, he showed that this increase in precipitation might nonetheless be associated with a slowdown of the Walker circulation.The second theme of Held's research is the general circulation of the atmosphere.In one of his earliest papers, he showed that when a region is unstable to the large-scale planetary waves known as Rossby waves, the propagation of waves out of this region results in an easterly (westward) acceleration, which generates jet streams in midlatitudes.