Diagnosing moisture transport using D/H ratios of water vapor

Water vapor transport paths into the American Southwest were deduced from a high temporal resolution record of hydrogen isotope compositions of atmospheric water vapor (delta D-wv) collected over a six-week period in late spring, 2005, at Albuquerque, New Mexico. Daily fluctuations of delta D-wv routinely exceeded 20 parts per thousand in magnitude, while delta D-wv variations up to 80 parts per thousand occurred on the time scale of weather ( a few hours to similar to a week). Vertical profiles of delta D-wv in the lower troposphere exhibited considerable structure that cannot be ascertained from standard meteorological measurements. Trajectory analyses provide consistent evidence that the large temporal variations of surface delta D-wv and vertical variations of delta D-wv are primarily due to advection of water from different source regions. The lack of mixing inferred from our analyses indicates that delta D-wv can be used as a sensitive tracer of the moisture transport history of air parcels.