Posted by bobbapink on Jun 19, 2002 at 08:36
(208.58.228.38)
Re: ballons burst at 35 km (Amaranth Rose)
I found an interesting site about these. Here's a snip...
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The upper air system that gathers weather data has two main components. The first is the ground tracking system and is composed of the tracker, radio detection equipment, and a computer for analyzing data. The second is the rawinsonde which contains the data collecting and radio transmitting systems.
A rawinsonde (pronounced ray-win-sond) consists of a weather balloon, parachute, and an instrument package. Before it explodes, the balloon will expand unitil it's 40 feet in diameter and 35 feet tall. At the present time, a rawinsonde observation is the most accurate and cost-effective method for sampling the atmosphere above the surface of the earth. These observations are taken twice a day at 71 locations in the United States, 36 locations in Canada, and numerous other locations world-wide.
In Bismarck, the National Weather Service releases a rawinsonde at 5 AM and 5 PM CST (6 AM and 6 PM CDT). The balloon rises 1000 feet per minute and explodes at 90,000 feet about 1.5 hours later. During this time the instrument package gathers information about temperature, humidity, and pressure. Wind direction and speed is determined by tracking equipment on the ground. In many ways, this is the first step to forecasting the weather for the next few hours or even the next ten days.
Our office releases between 750 to 800 rawindsondes each year, the extra launches are for tests and launches that failed. About 1/3 of the radiosondes (the actual instrument package) are returned to the National Weather Service reconditioning branch at Kansas City, MO. These radiosondes are repaired and reissued for further use, some as many as seven times. Many of the Bismarck radiosondes float back to the earth about 40 to 60 miles east and southeast of Bismarck near the cities of Steele and Linton. Instructions on how to send us the radiosonde and a postage free envelope are included with each release.
Interesting Radiosonde Facts:
Balloon dimensions:
at surface: 5 feet in diameter, 6 feet tall
at 90,000 feet: 30 feet in diameter, 25 feet tall
The parachute is made out of a photodegradable orange plastic which opens when the balloon bursts and allows the instrument package to slowly descend to the ground.
Wind direction and speed are determined by change in angle and azimuth of the tracking antenna.
It takes about $8 worth of hydrogen to fill the balloon before a launch.
The data is sent back to the ground on a frequency of 1680 MHz (FM radios only go to 108 MHz).
There is 15 feet of string between the balloon and the parachute, then 100 feet of string to the instrument package.
Special permission must be given by the Bismarck FAA Control Tower before each launch.
In the darkness of winter, a light-stick is attached to the string to aid in visually initializing the tracking system.
