Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (134 KB)

Title: An analysis and implications of alternative methods of deriving the density (WPL) terms for eddy covariance flux measurements

Author: Massman, W. J.; Tuovinen, J. -P.;

Date: 2006

Source: Boundary-Layer Meteorology. 121: 221-227.

Publication Series: Scientific Journal (JRNL)

Description: We explore some of the underlying assumptions used to derive the density or WPL terms (Webb et al. (1980) Quart J RoyMeteorol Soc 106:85-100) required for estimating the surface exchange fluxes by eddy covariance. As part of this effort we recast the origin of the density terms as an assumption regarding the density fluctuations rather than as a (dry air) flux assumption. This new approach, which is similar to the expansion/compression approach of Liu (Boundary-Layer Meteorol 115:151-168, 2005), eliminates the dry-air mean advective vertical velocity from the development of theWPL terms and allows us to directly compare Liu's assumptions for deriving the WPL terms with the analogous assumptions appropriate to the original expression of theWPL terms.We suggest, (i) that themain difference between these two approaches lies in the interpretation of the turbulent exchange flux, and (ii) that the originalWPL formulation is the more appropriate approach. Given the importance of the WPL terms to accurate and reliable measurements of surface exchange fluxes, a careful analysis of their origins and their proper mathematical expression and interpretation is warranted.

Keywords: air parcel expansion/compression, mass conservation equations, trace gas fluxes

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Massman, W. J.; Tuovinen, J. -P. 2006. An analysis and implications of alternative methods of deriving the density (WPL) terms for eddy covariance flux measurements. Boundary-Layer Meteorology. 121: 221-227.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.