A SODAR was operating at the release site during the first experiment. Vertical profiles of horizontal wind speed and direction and vertical wind speed were measured from 20 to 600 m above ground. These profiles show that the wind during the release was directed toward East-Northeast at 20 m above ground and veered toward East-Southeast at higher altitudes. Also, an ascending vertical wind, probably due to atmospheric convection, was detected during the afternoon of 23 October.
During the first release five pairs of Constant Volume Balloons (CVB) were launched. The horizontal trajectory of these balloons at the beginning of the release was towards East-Northeast. Afterward, during the afternoon, the trajectory veered first towards the East and then towards the East-Southeast. In the early morning of 24 October, the CVB flight was again towards the East.
|
CVB |
starting hour (UTC) |
Duration (hh:mm) |
Final distance (km) |
Altitude (m asl) |
|
1-CH |
1319 |
0:39 |
21 |
400-100 |
|
1-F |
1330 |
2:00 |
100 |
500 |
|
2-CH |
1636 |
2:20 |
122 |
1500-500 |
|
2-F |
1703 |
1:43 |
104 |
900-700 |
|
3-CH |
2000 |
1:47 |
117 |
900-500 |
|
3-F |
2010 |
1:30 |
108 |
700-500 |
|
4-CH |
2359 |
1:02 |
51 |
550-100 |
|
4-F |
0001 |
2:39 |
110 |
900 |
|
5-F |
0354 |
1:46 |
45 |
900-200 |
|
5-CH |
0359 |
1:16 |
46 |
550-100 |
|
|
|
During the first release, measurements of atmospheric wind and turbulence were also performed at the release site with a sonic anemometer. In addition to wind speed and direction, friction velocity and heat flux were measured.
During the release the wind blew between 240 and 290 degrees, i.e. from West-Southwest to West-Northwest. The wind was westerly at the start of the release, with a tendency to be from West-Northwest until midnight, and from West-Southwest at the end of the release. The wind direction changed between South and West during the rest of the period. The wind speed during the release ranged between 4 and 7 m/s.
 |
|
Wind speed and wind direction measured at the release location by the sonic anemometer on 23 and 24 October. Wind speed is reported on the left axis while the direction from which the wind blows, measured from North, is reported on the right axis. A wind blowing from 270 degrees is a wind blowing exactly from West. |
The sensible heat flux showed the typical daily variation, being highest and positive during daytime (upward flux) and negative (downward flux) during night.
 |
|
Sensible heat flux measured by the sonic anemometer at the release location on 23 and 24 October. |