It’s been a long time coming, but my first set of papers on the tropical “precipitation pickup” are finally in press.  You can find a link to both papers on the “Publications” tab.  In Part I, I spend ~6000 words discussing the ways in which clouds and precipitation processes depend on column humidity.  It turns out that clouds don’t always care about column humidity.  This makes sense for certain clouds like shallow/congestus convective clouds or for deep stratiform clouds that don’t span the troposphere.  Yet, it has taken us nearly 15 years to actually put that down on paper.  I won’t summarize the paper.  If you want a quick summary, read the abstract.  But, I will mention a few things that didn’t get published in that paper that I think are interesting.  The first is that the precipitation pickup does not appear to be the result of a systematic change in stability.  The tropical atmosphere is broadly unstable almost everywhere.  Instability increases with column moisture, but it does not change state near the pickup in my simulations.  The second is that nobody I have had a conversation with has agreed on precisely what the “scale invariance” of some of the precipitation statistics really means.  If you, oh wise internet reader, have a suggestion, get in touch with me.