Setup
Site
(SP Field Measurements )The Tharandter Wald is the biggest forested area within
Saxony (Germany). His partly heterogeneous structure reflects
the typical conditions of a Mid-European forest. The Fluxnet
site “Anchor Station Tharandt - old spruce“ is located in
South-East of the Tharandter Wald (385 m ü. NN , 50°57'49" n.
Br, 13°34'01" östl. L. (bzgl. Bessel Ellipsoid) 5399344
RW, 5648446 HW (GK, Potsdamer Datum)).
General information to the site could be found on the Fluxnet page and the web page of the
IHM. The Google-Earth screen shot in Fig. 1
shows the transect over the clearing, which was aligned
according to the mean wind direction (West-East).
Fig. 1: Wind distribution (1.5.2008 - 1.5.2009) and aerial view on the site with tower
Tower, Sensors and Data aquisition
(SP Field Measurements
)In Fig. 1 one can spot the Fluxnet tower on the far right of
the transect. It has got a height of 42 m. Additional to this
tower we erected 2 scaffolding towers of 40 m height and one
telescope tower of 30 m height.
The wind vector was taken by 27 ultra sonic
anemometers/thermometers ('sonics') investigating 31 positions.
We applied seven sonics of type USA-1 (Metek GmbH, DE) at the
Fluxnet tower and nineteen sonics of type Model 81000V (R.M.
Young Meteorological Instruments, MI, US) at all other
positions. The sonics were mounted on booms in a distance of
2-3 m to the scaffolding towers and 1 m to the telescoping
tower. Regularly inspections of the sensors throughout the
experiment ensured an accurate vertical and horizontal
orientation.
A frame of 19 sonics was operated permanently at the towers
over one year using the heights 2, 10, 20, 30 and 40 m.
Additionally, 12 positions were temporarily operated by seven
rowing instruments to fill the gaps in between the main
positions
The Fluxnet system which includes a R3 was used as a reference
at the Fluxnet tower in a height of 42 m.
The signals of the sonics were sampled with 20 Hz
simultaneously over the whole experimental periods. Applying
interface converters (VS NetCom 413/411/423/823, Vision Systems
GmbH, Germany) the signals of the sonics were transfered to one
single personal computer via LAN and WLAN. This central data
acquisition system utilized a LabView program (written by A.
Christen at the MCR Lab at Basel University) which is able to
record up to 36 serial RS232 ports simultaneously. All raw data
were stored.
T1: Telescope Tower, 30 m (Clark-Mast, CM)
T2: Scaffolding tower, 40 m (GM1)
T3: Scaffolding tower, 40 m (GM2)
T4: Fluxnet Tower "Ankerstation Tharandter", 42 m (HM)
Fig. 2: Schema of the setup
Fig. 3: Data availability
Protocol
(SP Field Measurements
)- 30.04.2008: Start of the field measurements (base frame at
the towers)
- 06.08.2008: Mounting of Sensor 61 and 71 at height 2
m
- 04.09.2008: Mounting of Sensor 81 and 91 at height 2 m
- 14.11.2008: Mounting of Sensor 36 at tower 3 at height 24
m
- 06.11.2008: Dismantling of Sensor 71, 81 and 91
- 14.11.2008: Mounting of Sensor 16 and 17 at tower 1 at
height 5 m and 16 m
- 14.11.2008: Mounting of Sensor 26 and 27 at tower 2 at height 5 m and 15 m
- 22.12.2008: Dismantling of telescope tower 1 because of
potential frost damage (exclusive the 5 m level)
- 04.03.2010: Erecting of telescope tower 1 with all sensors
(inclusive 16 and 17)
- 30.04.2009: End of the field measurements