Sensitivity Analysis for Ascending Zero Pressure Balloons

Sammanfattning: This work analysed the sensitivity in ascending velocity for three different zero pressure balloons of different sizes. A program that considers the atmospheric and thermodynamic conditions was written to try and simulate the balloons ascent throughout the atmosphere. The sensitivity for ascending velocity was determined with the Monte-Carlo method and measuring the mean vertical velocity throughout the atmosphere. The performance of the simulated flight when compared to its real flight, was accurate in the troposphere and then started to deviate in the stratosphere. Whether the drag is underestimated or overestimated during the stratosphere would depend on the size of the balloon and when it is released. Changing the free lift for the balloons showed that small balloons have almost the same sensitivity in the troposphere as in the stratosphere, while a larger balloon could be more sensitive in either part, depending on the time it is launched. With a changing ground temperature, the balloons with less cloud cover would be more sensitive in the stratosphere. Balloons flying during hours with sunlight are less sensitive to a changing cloud cover than balloons that fly with little to no sunlight, but some more data should be analysed for a proper conclusion. Larger balloons are more sensitive with a changing ground albedo value compared to smaller balloons.