|Weather balloon and instrument package,|
with me for scale.
There's members of the South African Weather Service onboard, some of who will stay on the ship while others get off and work from the islands. Every night, a weather balloon is deployed from the ship - and tonight I went to observe and take pictures.
The balloon is filled with helium on the ship, but on land they're usually filled with hydrogen. A package is attached that measures temperature, dew point (from which humidity can be calculated), and wind speed and direction using a GPS. Last night's balloon went to 21 kilometers before popping. I didn't stay long enough to see how high tonight's went, but I did check out the real-time data plots (see picture below).
From land stations like on Gough Island, a balloon is launched twice a day at roughly the same moment. This global network provides data to forecast weather and track storm movements. It's easy to take for granted that an app on my phone will tell me the forecast, so it's very interesting to see in person how that data gets collected.
|Locations of weather service stations worldwide.|
|The ascension rate (green), temperature (red), and dew point (cyan) data is plotted in real time. |
The calculated humidity (dark blue) spiked likely due to the balloon going through a cloud layer.