Energy Balance Closure at a Variety of Ecosystems in the Czech Republic

0474730 - ÚFA 2018 DE eng A - Abstract
McGloin, R. - Šigut, L. - Sedlák, Pavel - Havránková, K. - Pavelka, M.
Energy Balance Closure at a Variety of Ecosystems in the Czech Republic.
Geophysical Research Abstracts. Göttingen: European Geosciences Union, 2017. EGU2017-1838. ISSN 1607-7962.
[EGU General Assembly 2017. 23.04.2017-28.04.2017, Vienna]
Institutional support: RVO:68378289
Keywords : energy balance closure * eddy covariance technique * ecosystems * unstable atmospheric conditions * complex topography * tall canopies * planar fit * atmospheric boundary layer
Subject RIV: DG - Athmosphere Sciences, Meteorology
http://meetingorganizer.copernicus.org/EGU2017/EGU2017-1838.pdf

A long-standing problem in micrometeorology is that at most eddy covariance sites around the world, the sum
of the sensible and latent heat measurements is less than the available energy, resulting in the so-called energy
balance closure problem. This study utilised the national network of eddy covariance towers in the Czech Republic
to examine the degree of energy balance closure at sites covering a wide variety of vegetation types and terrain
complexities. In addition, variation in closure under a range of meteorological conditions was also analysed. The
energy balance closure fractions for the different ecosystems ranged from 0.68 (beech forest) to 0.81 (spruce
forest). Best energy balance closure at each of the sites occurred in strongly unstable to moderately unstable
atmospheric conditions. As in previous studies, energy balance closure improved with increasing friction velocity,
although in this study the ratio of friction velocity and wind speed seemed to have a greater impact on energy
balance closure, particularly at the sites with tall canopies. At the Štítná site, in the Carpathian Mountains, evidence
suggested that the complex topography to the south of the eddy covariance tower was influencing the airflow and
resulting in low friction velocity measurements and poor energy balance closure results. Finally, applying the
sector-wise planar fit method and increasing the flux averaging period from 30 minutes to 1 hour resulted in minor
increases in energy balance closure at the majority of sites.
Permanent Link: http://hdl.handle.net/11104/0271705