Next Article in Journal
Review on the Projections of Future Storminess over the North Atlantic European Region
Previous Article in Journal
Prediction of a Visible Plume from a Dry and Wet Combined Cooling Tower and Its Mechanism of Abatement
Article Menu

Export Article

Open AccessArticle
Atmosphere 2016, 7(4), 61; doi:10.3390/atmos7040061

Coherent Momentum Exchange above and within a Scots Pine Forest

Environmental Meteorology, Albert-Ludwigs-University of Freiburg, Werthmannstrasse 10, Freiburg D-79085, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: Robert W. Talbot
Received: 20 January 2016 / Revised: 13 April 2016 / Accepted: 18 April 2016 / Published: 21 April 2016
View Full-Text   |   Download PDF [3130 KB, uploaded 25 April 2016]   |  

Abstract

Biorthogonal decomposition (BOD) is used to detect and study synchronous coherent structures occurring at multiple levels in the vertical momentum flux (u′w′) within and above a planted Scots pine forest during a 12-week continuous measurement period. In this study, the presented method allowed for the simultaneous detection and quantification of the number of coherent structures (N), their duration (D) and separation (S) at five measurement heights (z1–z5) covering the range z1/h = 0.11 to z5/h = 1.67, with h being the mean stand height at the measurement site. Results presented for five different exchange regimes (C1–C5) and for four different atmospheric stability conditions (stable, transition to stable, near-neutral, forced convection) demonstrate that during the measurement period, above-canopy momentum flux was only to a limited extent involved in the evolution of spatiotemporal momentum flux patterns found within the below-canopy space. Fully-coupled turbulent momentum exchange over the investigated height range occurred during 19% of all analyzed half-hourly datasets. Across the analyzed exchange regimes, the median contribution of strong sweeps and ejections to total momentum transfer above the canopy varied between 30% and 39% while covering 28%–32% of the time. In the below-canopy space, the contribution of coherent structures varied between 19% and 21% while covering the same amount of time. This suggests that momentum transfer through synchronous coherent structures is very efficient above the forest canopy, but attenuated in the below-canopy space. Since the majority of the presented results agrees well with the results from previous studies that analyzed coherent structures at single levels, the BOD is a promising tool for the consistent investigation of synchronous coherent structures at multiple measurement heights. View Full-Text
Keywords: momentum flux; coherent structures; biorthogonal decomposition; wavelet analysis; Scots pine (Pinus sylvestris L.) momentum flux; coherent structures; biorthogonal decomposition; wavelet analysis; Scots pine (Pinus sylvestris L.)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Mohr, M.; Schindler, D. Coherent Momentum Exchange above and within a Scots Pine Forest. Atmosphere 2016, 7, 61.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Atmosphere EISSN 2073-4433 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top