Assessing decoupling of above and below canopy air masses at a Norway spruce stand in complex terrain

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62156489%3A43210%2F20%3A43918319" target="_blank" >RIV/62156489:43210/20:43918319 - isvavai.cz</a>

Alternative codes found

RIV/68378289:_____/20:00536068 RIV/86652079:_____/20:00532504

Result on the web

<a href="https://doi.org/10.1016/j.agrformet.2020.108149" target="_blank" >https://doi.org/10.1016/j.agrformet.2020.108149</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.agrformet.2020.108149" target="_blank" >10.1016/j.agrformet.2020.108149</a>

Result language

angličtina

Original language name

Assessing decoupling of above and below canopy air masses at a Norway spruce stand in complex terrain

Original language description

Concurrent below and above canopy sonic anemometer vertical velocity (w) measurements reveal frequent decoupling events between the air masses below and above the canopy at a dense spruce forest stand in mountainous terrain. Decoupling events occurred predominantly during nighttime but not exclusively. Several single-level approaches based on steady state and integral turbulence characteristic tests as well as friction velocity (u(*)) filtering and two-level CO2 flux filtering methods are tested. These tests aimed at evaluating the filtering schemes to address decoupling and its effect on above canopy derived eddy covariance net ecosystem CO2 exchange (NEE). In addition to the already existing two-level filtering approach based on the correlation of sigma(w) above and below canopy, two new filtering methods are introduced based on w raw data below and above the canopy. One is a telegraphic approximation agreement, which assumes coupling when w both above and below canopy are pointing in the same direction. Another one evaluates the cross-correlation maximum between below and above canopy w data. This study suggests that none of the single-level approaches can detect decoupling when compared to two-level filtering approaches. It further suggests that the newly introduced two-level approaches based on w raw data may have advantages in comparison to the conventional sigma(w )approach regarding their flexibility on shorter time scales than one year. We tested the correlation of the newly introduced filtering approaches with the parameters u(*), global radiation, buoyancy forcing across the canopy and wind shear across the canopy. In any case, this correlation was not existing or weakly positive, suggesting that concurrent below and above canopy measurements are necessary for addressing decoupling. Sonic anemometer measurements near the forest floor and above the canopy are adequate to apply the new procedures and can be implemented in a routine manner at any forest site globally.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

40101 - Agriculture

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Agricultural and Forest Meteorology

ISSN

0168-1923

e-ISSN

—

Volume of the periodical

294

Issue of the periodical within the volume

15 November

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

12

Pages from-to

108149

UT code for WoS article

000566373700017

EID of the result in the Scopus database

2-s2.0-85089736629