Disjunct eddy covariance

From Glossary of Meteorology

disjunct eddy covariance

The disjunct eddy-covariance method is a direct method to measure turbulent fluxes suitable for compounds for which no fast response sensors are available.

The disjunct eddy-covariance method is based on the same approach as the eddy-covariance method (EC): the vertical flux is the covariance of the vertical wind speed and the transported quantity. In the standard EC method, the sampling interval of vertical wind speed and concentration are equal (and of the same order as the response times of both instruments). In the disjunct eddy covariance, the response time of the instrument (slow) and the response time of the sampling (necessarily fast) are decoupled: the fast response of the sampling is attained by taking air samples over a short time span (typically 0.1–0.5 s). These samples are subsequently analyzed over a time span that is dictated by the slow instrument. Because of the long analysis time, the number of concentration samples is typically 1 to 2 orders of magnitude smaller than the number of wind speed samples.

Term edited 14 July 2016.


Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.