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    JAN MAYEN: JMIC/Monitorhytta, JNW/Liberg, JNE/Ulla, JMI/Trolldalen    

   SPECTROGRAM COMPARISON

UNIVERSITY OF BERGEN
Department of Earth Science
 Allé gt. 41, N-5007 Bergen, Norway 
             
0.1 DRAFT - for comments - 5 Feb, 2019 OM OM -
VER. STATUS CHANGE DATE BY CHK APP

1 LOCATIONS


2 SPECTRA (VERTICAL) COMPARISON, ALL JAN MAYEN STATIONS, 15-19 OCT. 2018


2.1 The complex wind patterns at Jan Mayen


From: https://www.yr.no/kart/?spr=eng#lat=71.01416&lon=-6.41338&zoom=8&laga=vind&proj=3575

Click for large version. Click for large version.

2.2 Spectra


Click photo to see album from that location: Jan Mayen Met. station,
Olonkinbyen:

Wind data:
Direction, average and gust values
JMIC / Monitorhytta (NORSAR) JNW / Liberg (UiB-GEO) JNE / Ulla (UiB-GEO) JMI / Trolldalen (UiB-GEO)
Click to visit JMIC photo album. Click to visit JNW photo album. Click to visit JNE photo album. Click to visit JMI photo album.
15 October 2018 - Click to enlarge.
Click to enlarge. Click to enlarge. Click to enlarge. Click to enlarge. Wind data, 15 Oct 2018, from 00 UTC, hourly values
16 October 2018 - Click to enlarge.
JMIC / Monitorhytta (NORSAR) JNW / Liberg (UiB-GEO) JNE / Ulla (UiB-GEO) JMI / Trolldalen (UiB-GEO) Wind data, 16 Oct 2018, from 00 UTC, hourly values
Click to enlarge. Click to enlarge. Click to enlarge. Click to enlarge.
17 October 2018 - Click to enlarge.
JMIC / Monitorhytta (NORSAR) JNW / Liberg (UiB-GEO) JNE / Ulla (UiB-GEO) JMI / Trolldalen (UiB-GEO) Wind data, 17 Oct 2018, from 00 UTC, hourly values
Click to enlarge. Click to enlarge. Click to enlarge. Click to enlarge.
18 October 2018 - Click to enlarge.
JMIC / Monitorhytta (NORSAR) JNW / Liberg (UiB-GEO) JNE / Ulla (UiB-GEO) JMI / Trolldalen (UiB-GEO) Wind data, 18 Oct 2018, from 00 UTC, hourly values
Click to enlarge. Click to enlarge. Click to enlarge. Click to enlarge.
19 October 2018 - Click to enlarge.
JMIC / Monitorhytta (NORSAR) JNW / Liberg (UiB-GEO) JNE / Ulla (UiB-GEO) JMI / Trolldalen (UiB-GEO) Wind data, 19 Oct 2018, from 00 UTC, hourly values
Click to enlarge. Click to enlarge. Click to enlarge. Click to enlarge.

3 RESONANCE FREQUENCIES IN WIND GENERATOR MAST


Spectrum of JNE/Ulla sensor on a day with little wind. Web page of the wind generator that is installed - Superwind model 353 - says rotor speed: 500-1300 rpm, which means between 8.3 - 21.7 Hz. It is, however, difficult to identify spectra lines in the lower end of this region (since that day was quiet - apart from the band below 10 Hz which is fluctuating somewhat - but most prominent noise components is much higher. That is why we think it is more likely that noise is caused by tower structural resonances, that are activated by the wind.

Click to enlarge.

Sensor site JNE/Ulla: Spectrogram 25 Nov, 2018. Click to enlarge.

3.1 Wind induced vibration


Hydrological Open Air Laboratory (HOAL), Petzenkirchen, Austria

Quote from this source: "The structure is a 9.1 m (30 ft) tall guyed mast and consists of three parts. Each part of the mast has an equilateral triangular cross section, whose dimensions respectively from bottom to top are 0.43, 0.34 and 0.26 m (seeFig. 1a). Each part of the mast is composed of three main legs together with the horizontal and cross bracing elements, made of aluminium alloy. In order to prevent the excessive lateral displacement, three cables from either side account for the additional constraint on the upper part of the mast. The structure is located in Petzenkirchen, Austria and serves as a weather station tower in the Hydrological Open Air Laboratory (HOAL) (Blöschl et al., 2016)."

Click to enlarge.

Source

Click to enlarge.

Source

3.1.1 Accelerometer used


3.2 Impulse technique


Source

4 APPENDIX


4.1 SPECTRA COMPARISON, 1-27 SEPTEMBER, 2018: JMIC / JNE / JMI


NOTE: JNE/ULLA sensor was installed inside plastic tube; this operation was a bit complicated and required two visits to the site. It started 6 September 2018 at 10 UTC (approx) and was finished 10 September at 10 UTC (approx). In this period the seismometer was disconnected - the data gap is visible.

VERTICAL EAST-WEST NORTH-SOUTH
JMIC / MONITORHYTTA, 1-27 SEPT, 2018 - Click to enlarge.
Click to enlarge. Click to enlarge. Click to enlarge.
JNE / ULLA, 1-27 SEPT, 2018 - Click to enlarge.
Note data gap between 6 September 2018 at 10 UTC (approx) to 10 September at 10 UTC (approx). In this period the seismometer was disconnected.
Click to enlarge. Click to enlarge. Click to enlarge.
JMI / TROLLDALEN, 1-27 SEPT, 2018 - Click to enlarge.
Click to enlarge. Click to enlarge. Click to enlarge.

4.2 JNE SPECTRA COMPARISON - BEFORE AND AFTER INSTALLING SENSOR IN PIT


VERTICAL EAST-WEST NORTH-SOUTH
JNE / ULLA: BEFORE AND AFTER - Click to enlarge.
Data gap between 6 September 2018 at 10 UTC (approx) to 10 September at 10 UTC (approx).
Click to enlarge. Click to enlarge. Click to enlarge.
Click to enlarge. Click to enlarge.

4.3 JNE/ULLA: INSTALLING SENSOR IN PIT - SOME PHOTOS


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Page last modified on February 05, 2019, at 03:48 PM
Electronics workshop
Department of Earth Science - University of Bergen
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