The National Science Foundation (NSF) under NSF Grants ATM-0215358 and ATM-0539969 provided partial financial support. I thank Dennis Lamb for fruitful discussions and Alan Betts for his constructive review.
OFCM, 1997: Federal meteorological handbook No. 3: Rawinsonde and pibal observations. Office of the Federal Coordinator for Meteorological Services and Supporting Research, FCM-H3-1997, 191 pp. [Available online at http://www.ofcm.gov/fmh3/text/default.htm and from National Climatic Data Center, Federal Building, 151 Patton Avenue, Asheville, NC 28801-5001.].