Temperature as well as static pressure are measured by XC vario. As a results, it is possible to plot temperature as function of pressure altitude.
Below are plotted a few time slices as recorded. Several observation can be made :
- Flying straight in sink or neutral zone results in measuring a certain gradient of temperature versus altitude - generally steeper than -6.5deg standart atmosphere gradient.
- Circling & climbing in a thermal shows a similar temperature gradient versus altitude compared to measured in straight flight, but with an offset corresponding to warmer air
- While entering or exiting the thermal, a transition happens in the same order of magnitude : we end up drawing an hysteresis
- The greater the climb, the greater the "warm offset"
- Those observations seem to remain true for strong climb in mountain area as well as weak thermal over flat land on a poor day
Using temperature sensor as a "thermal sniffer" is not the objective here, nevertheless collecting this data could be worthwhile in term of validating weather models - particularly if coming from a network of gliders flying the same area.
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Strong thermal at Malaup montain on the 13th of september 2021
- Transition
- 3.95m/s mean value over 850m climb
- Transition
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Good thermal at La Molière (north Vercors) on the 13th of september 2021
- Transition in a uplift area, then sink
- 2.1m/s mean value over 320m climb
- Transition
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Soft climb at Gache mountain on the 13th of september 2021- Transition
- 1.1m/s mean value over 370m climb
- Transition
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Weak thermal over flat land on the 9th of october 2021
- Transition
- 0.6m/s mean value over 100m climb
- Transition
