LTER Zöbelboden, Austria, Metadata - Eddy covariance tower

Basic Information

Abstract

The LTER site Zöbelboden was equipped with highly modern infrastructure to assess the effects of extreme climate events on the forest ecosystem. The instruments include eddy covariance measurements for CO2 and water vapor fluxes at a tower (900 m a.s.l), and soil respiration auto-chambers, as well as combined sap flow sensors with automated dendrometers in the main footprint area of the eddy tower. This is the so called intensive plot 2 (IP2), which is equipped by a number of different field measurement devices for long-term monitoring (lysimeters water sampling, soil moisture and temperature sensors, manual dendrometers, deposition, litter fall) and supplemented by other monitoring activities (tree inventory, needle and leaf chemistry, soil chemistry). An optical multi-parameter probe for dissolved nitrogen and carbon was installed in the measuring weir of the catchment runoff at 577 m a.s.l. There, weekly water quality, runoff, and meteorology is monitored since many years. The related metadata refer to eddy covariance measurements. The data can be viewed and downloaded via the link provided using the station name “ZOE_0917F00”.

Keywords

Contact

Owner/Creator

Environment Agency Austria (EAA)

Metadata Provider

Gisela Proell

UUID

8a4f7e18-b5b8-4ffa-9d68-e3e47972ee0b

Dates

Date Range

Tue, 07/01/2014 - 12:00

Post date

Thursday, June 18, 2020 - 13:18

Last modified

Wednesday, July 7, 2021 - 11:46

Downloads

Online Locator

Distribution Function

Web address (URL)

Distribution URL

LTER-CWN time series management system

Geographic

Show details for observation location(s):

LTER Zöbelboden Measuring Tower

Additional information

Methodology

Method Description

The extremely complex topography surrounding the tower at Zöbelboden render the site conditions non-ideal for EC measurements of net turbulent forest atmosphere exchange. Therefore, a pilot study was carried out already starting in summer 2014 in the course of the C-Alps project through the Life Science University, Vienna. The measurement system consisted of a HS 100 ultrasonic anemometer (Gill Instruments, UK) and a Li-7200 enclosed CO2/H2O gas analyser (LICOR Biosciences, USA). The instruments were mounted above the forest canopy on the existing tower at a height of 33 m. In February 2015, an additional CO2 gradient system (WMA 4 CO2 analyzer (PP systems, USA), plus CR23x datalogger (Campbell Scientific, USA) and multiplexer) was installed to measure CO2 concentrations over the vertical profile of the tower, and thus infer storage and vertical advection CO2 fluxes, which of course were missed by the EC system alone. A month later, temperature and humidity sensors (EMS 33, EMS, Czech Republic) were added to the gradient system, with a CNR4 net radiometer (Kipp & Zonen, Netherlands) installed above the canopy at 40 m height. To investigate the influence of advection further, two below-canopy HS 100 Anemometers were installed at 2 m heights in 2017 to observe the extent of decoupling between the flow above the canopy and the flow at the forest floor on the plateau at the base of the tower and on the steep slope north of the tower.
The micrometeorological instruments deployed during the test campaigns were dismounted in the autumn of 2017. A new eddy covariance system, purchased for long-term flux measurements at the site, was subsequently installed in December 2017. This system consists of a LICOR Enclosed Path system (LI-7200RS CO2/H2O Analyzer) with a sonic anemometer (Gill windmaster, 7900-420) and an automated flux processing computer (LICOR SMARTFlux 2 System).

Sampling Time Unit

minutes

Sampling Time Span

minutes

Quality Assurance

General functioning of the device is done daily to weekly, based on checks of the data which are automatically transferred to our in-house data archiving facility. Every month, the window/optic of the measuring path is cleaned with Ethanol; filters are checked and eventually cleaned with water. Furthermore, the signal strength and diagnostics (e.g. thermocouples) are checked, and the Sonic temperature is compared against the IRGA air temperature (Sonic > IRGA). Every 6 months, a calibration is done in a certified lab against zero and span values of 0 ppm CO2 and H2O, 400 ppm CO2, and dew point at 20°C, respectively.
The settings for the flux calculations are based on the findings of the pilot study. Plausibility checks are done daily to weekly, based on the automated data transfer. Continued checking of energy balance closure is done by comparing the sum of the sensible and latent heat fluxes against corresponding net radiation values minus the ground heat flux, which are measured with a Net radiometer (Kipp Zonen CNR4) at the tower and heat flux plates in IP2 (3 Huxeflux HFP01SC-05). The net radiometer and heat flux plates were installed in spring 2018. In contrast to the previous net radiometer, the current sensor was installed at a measurement height of 42 m. All fluxes are assigned quality flags following the standard 0-1-2 scheme (Foken et al. 2012). We strongly recommend using only flag 0 fluxes that satisfy stringent criteria with respective to turbulent flux similarity and stationarity. Furthermore, we urge caution in interpreting these flag 0 data given very complex terrain and heterogeneous forest stand characteristics in the area surrounding the tower.

Foken, T., Leuning, R., Oncley, S. R., Mauder, M., & Aubinet, M. (2012). Corrections and data quality control. In Eddy covariance (pp. 85-131). Springer, Dordrecht.

Other

Parameters

atmospheric parameter

Spatial Design

regular

Intellectual Rights

Formal acknowledgement of the dataset providers

Spatial Scale

catchment

INSPIRE Data Theme

Environmental monitoring facilities