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The spatial scale dependence of water vapor variability inferred from observations from a very tall tower

Pressel, Kyle G. and Collins, William D. and Desai, Ankur R. (2014) The spatial scale dependence of water vapor variability inferred from observations from a very tall tower. Journal of Geophysical Research. Atmospheres, 119 (16). pp. 9822-9837. ISSN 2169-897X.

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Recent studies have established that atmospheric water vapor fields exhibit spatial spectra that take the form of power laws and hence can be compactly characterized by scaling exponents. The power law scaling exponents have been shown to exhibit substantial vertical variability. In this work, Taylor's frozen turbulence hypothesis is used to infer the first-order spatial structure function and generalized detrended fluctuation function scaling exponents for scales between 1 km and 100 km. Both methods are used to estimate the Hurst exponent (H) using 10 Hz time series of water vapor measured at 396 m altitude from an Ameriflux tower in Wisconsin. Due to the diurnal cycle in the boundary layer height at the 396 m observational level, H may be estimated for both the daytime convective mixed layer and the nocturnal residual layer. Values of H ≈ 1/3 are obtained for the convective mixed layer, while values of H > 1/2 apply in the nocturnal residual layer. The results are shown to be remarkably consistent with a similar analysis from satellite-based observations as reported in Pressel and Collins (2012).

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Additional Information:© 2014 American Geophysical Union. Received 4 NOV 2013; Accepted 10 JUL 2014; Accepted article online 15 JUL 2014; Published online 28 AUG 2014. This research was supported by the Director, Office of Science, Office of Biological and Environmental Research of the U.S. Department of Energy under contract DE-AC02-05CH11231 as part of their Regional and Global Climate Modeling Program. Observations at the WLEF Park Falls Ameriflux site are supported by National Science Foundation (NSF) DEB-0845166, the Department of Energy Lawrence Berkeley National Lab Ameriflux Network Management Project, and NOAA Earth Systems Research Lab. These observations were made with the assistance of Jonathan Thom, University of Wisconsin-Madison; Arlyn Andrews, NOAA ESRL; Jonathan Kofler, NOAA ESRL; and Dan Buamann, U.S. Geological Survey. We are grateful for support by the Terrestrial Hazard Observation and Reporting (THOR) Center at Caltech and by the National Science Foundation (grant ARC-1107795). The flux and meteorological data from the WLEF tower are free, fair use, and available online at and also archived at the Fluxnet/Ameriflux repository. The high-frequency WLEF tower observations used in this study are available online at
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Department of Energy (DOE)DE-AC02-05CH11231
NSF DEB-0845166
Lawrence Berkeley National Lab Ameriflux NetworkManagement Project UNSPECIFIED
NOAA Earth System Research LaboratoryUNSPECIFIED
Terrestrial Hazards Observation and Reporting CenterUNSPECIFIED
Record Number:CaltechAUTHORS:20141022-113506470
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Official Citation:Pressel, K. G., Collins, W. D., & Desai, A. R. (2014). The spatial scale dependence of water vapor variability inferred from observations from a very tall tower. Journal of Geophysical Research: Atmospheres, 119(16), 9822-9837. doi: 10.1002/2013jd021141
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50681
Deposited By: Joanne McCole
Deposited On:23 Oct 2014 18:43
Last Modified:20 Feb 2015 18:13

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