A comment by Nick Lancaster
Dan - A great use of the mobility index. It really seems to work here, but when one gets to southern California, the index appears to break down. For this see abstracts by Patterns of winds and aeolian activity in the deserts of southern California, N. Lancaster, A. Bach, A.J. Brazel, Association of American Geographers 1995 Annual Meeting Program and Abstracts, 166 , March 1995.
Response to Nick Lancaster
A comment by Daniel R. Muhs
Nick: Yes, I agree that there seem to be problems with the dune mobility index in the Mojave, but it does seem to work OK for the more arid Salton Trough area (see our Algodones paper in Vache's volume, for example). I haven't read your abstract--can you mail a xerox of it to me (Dan Muhs, USGS, MS 980, Box 25046, Federal Center, Denver, CO 80225), because our library doesn't get the AAG abstracts. Your index seems to work well for the Great Plains, the Chihuahuan Desert, the Colorado Plateau, and the Sonoran Desert--it seems there is something about the Mojave that is different. On the other hand, as we've discussed, we need to evaluate the index for other continents. By the way, I apologize for omitting a reference to your 1988 JAE paper on the Kalahari where the index was introduced. We are in the process of rectifying this oversight. --Dan