Kytoon observations of the Lake Mead boundary layer
On July 14--16, 1997 nearly 60 hours of kytoon sampling of the boundary layer at Lake Mead was done through a cooperative effort among the U.S. Geological Survey, National Oceanic Atmospheric Administration, and U.S. Bureau of Reclamation. Micrometeorological data (MET) were analyzed to find boundary layer characteristics of height, precipitable water content, and precipitable water content residence time. In addition, the boundary layer precipitable water content was compared to tributary inflows in an approximated Lake Mead water compariSon The kytoon data was unique and indicated the boundary layer at Lake Mead maintained an inversion during day and night and in all samples collected. The Lake Mead boundary layer was characterized by higher dew points than the surrounding Mojave Desert air mass. In addition, the mountainous terrain around the lake represents a potential influence for isolating the Lake Mead boundary layer, preventing its migration to other locales, and allowing the development of an "oasis effect". The atmosphere immediately above Lake Mead contained a sustained inversion based on ambient and dew point temperatures with an average height of 49.3 meters for the three-day sampling period. This value exceeds the estimated value of 8.024 meters assumed by a previous evaporation study done at Lake Mead. The precipitable water content in the boundary layer was also determined to average 218 acre-feet for the three-day sample period and the average residence time based on basin location was 3.4 days. When compared to the tributary inflows in an approximated Lake Mead water comparison, the Lake Mead boundary layer precipitable water content was equivalent to the combined daily tributary inflow from the Muddy River and Virgin River.
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