Key points are not available for this paper at this time.
Author Posting. © IOP Publishing, 2009. This is the author's version of the work. It is posted here by permission of IOP Publishing for personal use, not for redistribution. The definitive version was published in Environmental Research Letters 4 (2009): 024007, doi:10.1088/1748-9326/4/2/024007.
Cooley et al. (Mon,) studied this question.