by Anastassia Makarieva
A quick overview of the case (relevant documents are below). The authors (Makarieva, Gorshkov, Sheil, Li) submit a manuscript to the Geophysical Research Letters (GRL) where they show that precipitation mass sink in the equatorial region produces sufficiently large pressure gradients to drive Hadley cell. The Editor writes in the first decision letter that the manuscript can be publishable provided the authors respond to the concerns of the second referee. The first referee is strongly positive and finds the paper important. The second referee writes 138 words:
This paper is interesting but somewhat confused. Without dwelling on the details of calculating the effect of precipitation on surface pressure, the attempt to relate such changes to large scale motion systems seems to ignore the fact that they are referring to balanced flows. Thus, pressure gradients per se do not drive the Hadley circulation. Rather, the momentum balance leads to circulations that maintain pressure gradients consistent with geostrophy. The actual way the pressure gradients are produced is essentially irrelevant though it would be potentially interesting if the mechanism involved precipitation. The fact that Held and Hou do not provide a quantitatively realistic description of the Hadley circulation is almost certainly due to the omission of eddies (Robinson, 2006, JAS, Walker and Schneider, 2004, GRL, 2006, JAS) and the assumption of equinoxial conditions (Lindzen and Hou, 1988, JAS).
The Editor points out that it is very important to attend to these comments and emphasizes that how pressure gradients are produced is irrelevant for the Hadley cell. They warn the authors that their response and the revised manuscript will be shown to referee No. 2 as well as to a third referee, if needed.
The authors are encouraged by the fact that one referee is excitied, another one finds the paper interesting. They draft a detailed reply, where they clarify that without a pressure gradient the Hadley cell would stall and that while the conventional paradigm considers differential heating as the cause of this gradient, they offer a new driver (precipitation mass sink).
The authors submit the revised version of the manuscript. Continue reading