posted Oct 1, 2015, 10:21 AM by Manuel Roca
Relative Humidity & Temperature
Profiles of Temperature and Relative Humidity are useful to evaluate the atmosphere behavior. Increments on Relative Humidity are evidence of cloud layers and abrupt variations on Temperature are evidence of thermal inversions characteristic of the boundary layer and tropopause.(Click on the figures to enlarge) Water VaporThe amount of water vapour contained in the atmosphere is represented by its mixing ratio profile, that shows the volume ratio between water vapor and dry air [ppmv] (parts per million in volume). The mixing ratio is a better form to show the water content than relative humidity because it depends of a combination among temperature, pressure and relative humidity.
On the left, mixing ratio for both acquisition systems in function of height. The linear scale is not appropiated for the display of low values or to identify the tropopause. However, It shows as the amount of water vapor varies throughout the height profile.
On the right, we use the logarithm of mixing ratio to better appreciate the lowest values, especially near to the tropopause. A progressive increment of water vapor in the stratosphere is observed using this logarithmic plot. (Click on the figures to enlarge)
Ascent rateThe ascent rate depends directly on the balloon volume. Indeed, increasing the pressure of helium used to fill the ballon, the ascent will be faster. However, it is important to keep an ascent rate of about 5 m/s because the atmosphere may undergo quick changes and if the ascent rate is too low, the measurements will not be representative. Conversely, if the ascent rate is too high the radiosonde will not take sufficient measurement points.
The figure shows the ascent rate comparing on-board GPS and PTU (pressure, temperature and humidity) measurements. (Click on the figure to enlarge)
Balloon trajectoryThe first three figures show the balloon trajectory overlayed to a GoogleEarth image, from the launching point to the maximum height reached. The last one shows a complete height profile overlayed on a surface image of Google Map. (Click on the figures to enlarge)
The principal parameters of launch preparation and flight are shown in the table below.
Photo galleryTaken from the launching point. Some pictures show the direction towards they were taken.
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