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Article
Characteristics of Water Vapor Turbulence Profiles in Convective Boundary Layers During the Dry and Wet Seasons Over Darwin
Journal of Geophysical Research: Atmospheres
  • M. K. Osman, NOAA National Severe Storms Laboratory
  • D. D. Turner, National Oceanic and Atmospheric Administration
  • T. Heus, Cleveland State University
  • R. Newsom, Pacific Northwest National Laboratory
Document Type
Article
Publication Date
5-27-2018
Disciplines
Abstract

©2018. American Geophysical Union. All Rights Reserved. This study explores water vapor turbulence in the convective boundary layer (CBL) using the Raman lidar observations from the Atmospheric Radiation Measurement site located at Darwin, Australia. An autocovariance technique was used to separate out the random instrument error from the atmospheric variability during time periods when the CBL is cloud-free, quasi-stationary, and well mixed. We identified 45 cases, comprising of 8 wet and 37 dry seasons events, over the 5-year data record period. The dry season in Darwin is known by warm and dry sunny days, while the wet season is characterized by high humidity and monsoonal rains. The inherent variability of the latter resulted in a more limited number of cases during the wet season. Profiles of the integral scale, variance, coefficient of the structure function, and skewness were analyzed and compared with similar observations from the Raman lidar at the Atmospheric Radiation Measurement Southern Great Plains (SGP) site. The wet season shows larger median variance profiles than the dry season, while the median profile of the variance from the dry season and the SGP site are found to be more comparable particularly between 0.4 and 0.75 zi. The variance and coefficient of the structure function show qualitatively the same vertical pattern. Furthermore, deeper CBL, larger gradient of water vapor mixing ratio at zi, and the strong correlation with the water vapor variance at zi are seen during the dry season. The median value in the skewness is mostly positive below 0.6 zi unlike the SGP site.

Comments
This work was supported by the U.S. Department of Energy Atmospheric System Research (ASR) program via grant DE‐SC0014375.
DOI
10.1029/2017JD028060
Citation Information
M. K. Osman, D. D. Turner, T. Heus and R. Newsom. "Characteristics of Water Vapor Turbulence Profiles in Convective Boundary Layers During the Dry and Wet Seasons Over Darwin" Journal of Geophysical Research: Atmospheres Vol. 123 Iss. 10 (2018) p. 4818 - 4836 ISSN: 2169897X
Available at: http://works.bepress.com/thijs-heus/26/