Matthew's Journal

Now that the ship is in full research mode, we're launching balloon upper-air soundings six times per day. That's every four hours around the clock. Some of my readers are probably asking themselves right now, "What's a balloon upper-air sounding?" Let me explain.

Meteorologists need to have information about the wind, temperature, and pressure structures in the atmosphere not just at the surface, but throughout the whole troposphere and well into the stratosphere. To obtain the information we need, we take a device, called a sonde, which has a temperature and humidity probe, a GPS antenna, and a radio transmitter and strap it to a balloon that travels high into the atmosphere recording information and transmitting it back to the surface. When it's all said and done, for the launch location you will be able to see the temperature, humidity, wind speed, and wind direction for any given height or pressure level that the balloon passed through.

Follow up:

The process starts by prepping the sonde for launch. We hook the sonde up to a configuration station that you can see in the picture of the sounding workstation below. We interface with the configuration station via computer and calibrate the sonde's sensors and set the radio frequency at which the sonde will transmit it's data back to earth.

The Sounding Workstation on the RV Ronald H. Brown

The sonde that we use is manufactured by Vaisala. The instrument package features a helical GPS antenna and a probe with temperature and humidity sensors that extend from the top of the plastic housing. The sonde is powered by a battery that you activate by soaking in water for about five minutes. A transmitter antenna wire extends from the bottom of the sonde.

A closeup view of a Vaisala radiosonde

Once you've prepped the sonde for launch, the next step in conducting an upper-air sounding is to inflate the balloon that will carry the sonde aloft into the atmosphere. We use latex 200g balloons that we fill with helium until the balloon is approximately four feet across. We fill the balloon from a standard sized 55" upright tank with a fill pressure of around 2500 psi and an output pressure through a regulator of about 400 psi. Typically we can launch between five and seven balloons per tank.

David Painemal of University of Miami filling a balloon

Once the balloon is filled, the final step is to attach the sonde and release the balloon into the air. Now, I'm sure that releasing the balloon sounds like the simple part of this process. We were all kids once and what kid hasn't had a helium balloon get away from them at least once? Releasing the balloon on the ship can be bit of a problem. You don't want the balloon to hit anything. The balloons are fragile and most objects are capable of popping the balloon. Also, the fantail of the Ronald Brown is very full of equipment. Factor in being on a boat sailing at 12 knots and you're faced with a situation where you have to navigate a metaphorical minefield with a balloon that can be violently buffeted in a strong wind gust. These aren't party balloons. The will try to get away from you. So, the challenge for us is to navigate around all the obstacles to a location at the back of the ship's fantail where you can release the balloon without worrying that it's going to be blown into some equipment or into the ship's superstructure. Though of course, I'm the onl one on the cruise who's popped a balloon so far.

David Painemal of University of Miami navigating the fantail of the RV Ronald H. Brown in an effort to get to a safe balloon release spot

So that, boys and girls, is a rundown of what it takes to perform an upper-air sounding from the Ronald Brown. I'd like to thank David Painemal for being a good sport about me taking pictures while we trained him to launch balloons.