Overview of the content

This lesson will cover:

  • Radiosonde fundamentals
  • Global and regional radiosonde networks
  • Radiosonde data visulization
  • Checklists prior to launch

Learning objectives

After completing this lesson, you will:

  • Understand fundamentals about radiosonde, including
    • the components of a radiosonde system and its measurements,
    • the variety of radiosonde networks and data display (Skew-T diagram)
  • Be familiar with the checklists prior to launch



Radiosonde diagramSounding

Sounding is the determination of one or several upper-air meteorological variables by means of instruments carried aloft by balloon, aircraft, kite, glider, rocket, and so on.


As described by the National Weather Service, a radiosonde is a small instrument package that is suspended below a balloon filled with either hydrogen or helium

The goal of a radiosonde is:

  1. To make accurate measurements of important atmospheric parameters (usually temperature, pressure, humidity and wind) above the surface
  2. To send this information back in as close to real-time as possible

Learning resources


Initialization checklist:Start check 30 minutes prior to launch 

[download this as a PDF (same content as listed below)]

  • Check batteries and change/charge if below 50% - ICOM/GSU/Computer/ 
  • Ground Station turned on and connected before starting GRAW program 
  • Connect sonde for initialization 
  • Open the GRAW program 
  • Go to Settings (top left corner of screen – notebook icon) 
  • Program Settings > Communications Tab 
  • Detect both COM Ports and Receiver 
  • Exit out of settings 
  • Click Sounding/Simulation (do not use the wizard – it is good to troubleshoot with this if the sonde will not initialize) 
  • Click Initialize radiosonde 
  • Set sonde and ground station to proper frequency 
  • Enter ground values recorded on data form by Lufft position 
  • Double check frequency and ground values are correct 
  • Click start sounding 
  • Enter lat/long and altitude (both lat and long require negative sign in Chile) 
  • Confirm raw data is coming in  
  • Turn sonde to on position 
  • Unplug radiosonde from computer and deliver to acclimation table 
  • Double check raw data is still coming in 
  • Run balloon fill prediction with current ground values (balloon = 600g; payload = 100g)  
  • Help with fill while sonde acclimates 
  • Get sonde to attach to balloon. 
  • Launch balloon 
  • Confirm software detected launch (if it doesn’t within 30 seconds launch manually) 

Saving Conventions: 

Profile Data:  W#_L#_LaunchTimeUTC_mmddyy_computer_Profile  

Raw Data: W#_L#_LaunchTimeUTC_mmddyy_computer_Raw  

SkewT: W#_L#_LaunchTimeUTC_mmddyy_SkewT  

BUFR: W#_L#_LaunchTimeUTC_mmddyy_computer_BUFR 

GSF:  Leave as default name 

Overview Form: W#_L#_LaunchTimeUTC_mmddyy_Overview 


Latitude_____________ Longitude_____________   Altitude_____________ 


Primary fill checklist: Begin 10 minutes prior to flight   

[download this as a PDF (same content as listed below)]

  • Check regulator attachment to helium tank  
  • Wait for OK to fill from person initializing and DGAC 
  • Note beginning psi level of helium tank 
  • Have initializer yell out fill value 
  • If tank will need to be changed during fill have 2nd tank next to 1st  
  • Get gloves  
  • Get balloon from box  
  • Attach helium nozzle to balloon neck  
  • Fill balloon (clockwise is open)  
  • Tap pressure gauge occasionally to get accurate level  
  • Remove nozzle from neck of balloon (don’t let go of balloon!)  
  • Allow secondary fill to attach sonde with zip tie 
  • Fold neck of balloon over and hold neck for duct tape  
  • Yell for verification of data from initializer  
  • Count down and launch  
  • Organize fill area and prep for next launch (remove empty tanks, throw away any garbage, replace tools to proper locations)  

Secondary Fill Checklist: Begin fill 10 minutes prior to flight  

[download this as a PDF (same content as listed below)]

  • Set out zip ties and 2x 1.5’ pieces of duct tape  
  • Have wire clippers in pocket  
  • Get gloves 
  • Wait for OK to fill from person initializing 
  • Unroll balloon  
  • If tank is changed mid-fill – Use all of 1st tank and note amount needed from 2nd tank then move regulator to 2nd tank  
  • Yell for radiosonde (primary initializer brings to fill)  
  • Attach zip-tie and radiosonde loop tightly to neck of balloon  
  • Clip extra end of zip-tie  
  • Cover zip-tie with one piece of duct tape  
  • Duct tape thoroughly over folded balloon neck 
  • Double check dereeler is not tangled  
  • Make sure no strings from sonde are tangled 
  • Count down and launch  
  • Organize fill area and prep for next launch (remove empty tanks, throw away any garbage, replace tools to proper locations)  

Video content

How Your National Weather Service Launches Balloons -- NOAA National Weather Service Albany, NY [YouTube video, 3:26]

  • This video generally describes how the NOAA National Weather Service launches a weather balloon from its forecast office in Albany.

Readings / articles

The NOAA office provides more information on sounding analysis at https://www.spc.noaa.gov/exper/soundings/help/index.html

Additional resources also available on their Jetstream Online Education page: https://www.weather.gov/jetstream/radiosondes


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