This launch was totally successful. A few changes I made to the setup:
- I attached the new recovery system as shown in the previous post.
- Launched in a more open area.
- I added a second spool of line, giving a total of nearly 500 yards (about 450 m).
Here are some pictures from the launch:
Before I show the figures, let me describe the conditions at launch. The winds were absolutely calm at the ground. There was not a cloud in the sky. And when I released the balloon, the sun had only been up for half an hour at most.
When the balloon rose, it drifted a long ways away, showing strong winds. Usually, when that happens, it is because we are in an inversion layer...cold air sinks to the surface, and warm air rises, causing still wind below and strong wind above. In the pictures above, you can see fog still present over the bodies of water. It was most definitely an inversion.
Here are the resulting plots from the launch:
    |
Notice that, unlike the first launch, the temperature rises over time. This is most definitely the sign of an inversion. The relative humidity also dropped with height, which was a result in the increased temperature (increased saturation vapor pressure).
Also, the temperature vs. altitude plot shows the same. The temperature rose with height. The inversion layer was definitely strongest at the surface (shallow portion), and weaker at higher altitudes (steeper portion). The lapse rates I am calculating are around 100*C/km and just under 10*C/km. The second number is believable, but the first seems a little excessive. It would definitely be a large number, but I am a little suspicious of this number... Something to look into.
Here's the balloon after recovery. It was tempting to run the program a second time and get a second set of data, but I needed to call it a day.
