The idea of a radiosonde that incorporates abilities of radio-controlled airplanes has been around for a long time. The vision is a radiosonde that is not disposable, but instead uses wings to glide back to the starting point or some other designated landing site to be recovered and reused. The objective is to save costs, especially if more expensive payload is attached, such as particle, ozone or radiation sensors. The concept is naturally called a “glidersonde”.
NSSL at NOAA investigated the idea in the 90’s. The AMS published a piece on the concept in their magazine BAMS in 2014 under the title “A Viable Alternative for Conducting Cost Effective Daily Atmospheric Soundings in Developing Countries“.
One stumbling block discussed in the literature is the regulatory difficulties of flying anything with self-control, even without active propulsion. Another problem cited is to find a business model that makes a reusable product interesting for companies currently selling a large volume of disposable radiosondes. A third problem is the span of competences needed to both manage aircraft design, sensors and meteorology.
Other projects worth mentioning is CICADA from NRL at the US navy, a prototype for military surveillance, and MAVIS Agnes from University of Southampton, United Kingdom, a prototype of a paper aircraft for atmospheric research.
Relation to Windsond
Windsond already lends some of the philosophy from the fabled glidersonde, given our focus on choosing landing site and recovering the radiosonde. The landing site can be selected along a geographical line defined by the current winds and the sonde is typically recovered within a 20-100 m radius from the predicted landing location.
But what if we could give the user a wide area wherein to select a landing site instead of a line, and what if we could further improve the landing accuracy? That would make the sondes easier to reuse.
During the spring of 2016, a thesis project at Sparv has investigated the feasibility of giving Windsond an aerodynamic shape and control surfaces, to expand the current line of possible landing locations to a big area. While earlier glidersonde discussions assume a target altitude of 30 000 m, we stick with the Windsond specs of 8 000 m to retain the extremely low weight, portability and ease of use.
The investigation shows we can achieve a big radius of selectable landing sites from the point of cut-down from the balloon. With low winds, the sonde can glide back to the launch site. At medium or strong winds, the sonde naturally needs to land somewhere downwind. It’s technically reasonable to achieve these flight characteristics with a 15 gram glidersonde. The technical analysis shows that all necessary parts fit in the tight space and weight budget. A glidersonde with mechanical actuators is naturally more expensive to manufacture than an ordinary radiosonde, but in reasonable volume the costs are manageable.
We still need to install suitable actuators and electronics and perform necessary tests and certifications. We don’t have a time plan or budget for this work until we find a customer to co-fund it. Economically, the savings possible for a single major field campaign would make this feasible. We hope to realize this concept sooner or later, to further push the limits of cost and convenience for boundary layer data collection.
EDIT June 10: ETH Zurich and Meteoswiss has carried out successful tests with a high-altitude glider radiosonde, using COTS components.
For some time, we have been working with atmospheric researchers to add instrumentation to quadcopters and radio-controlled airplanes. These are also called Unmanned Aerial Vehicles (UAV) or Remotely Piloted Air System (RPAS).
This is organized in the ISARRA community.
Now we announce a system specifically for this purpose, Sparv Sensors. It removes the need for researchers to also be engineers when setting up UAVs to measure temperature, humidity, gases, etc.
Anders is back from ISARRA in Toulouse, France. The conference regards Atmospheric Research using Unmanned Aircrafts. The conference had about 80 visitors from research programs and companies in Europe, USA, Japan and Korea. Anders also observed the flight campaign the week before in Lannemezan.
Thank you to Meteo France for organising this useful event!
We will post to Twitter using the #ISARRA hash tag.
Mississippi State University has used Windsond during the VORTEX-SE campaign during the spring 2016.
We interviewed professor Mike Brown about the experience.
What is your role in the VORTEX-SE project?MSU’s role in VORTEX-SE was to gather sounding data and quantify possible landscape-induced changes in the severe storm environment by exploiting simultaneous boundary-layer soundings on both sides of pronounced changes in the landscape. The sounding data collected will be used to quantify the strength of the boundary and related diurnal boundary layer response. which will provide a depiction of the mesoscale circulations. Differences in the sounding profiles at a pair of sites (on opposing sides of a boundary) will then be used to quantify the changes in local storm ingredients associated with the circulations. The high spatial and temporal resolution data will be compared to WRF model case study simulations to assess whether a routine operational-like forecast can adequately represent the mesoscale response. The data will then be assimilated into the WRF model to assess whether their inclusion can improve the skill of the model.What made you choose Windsond for soundings?We chose Windsond for a number of reasons. First, the small package makes it easy to deploy. Second, in near storm environments we would often launch every 15 minutes, the ability for Windsond to track up to 8 sondes was important to us. Additionally we liked the usb receiver which was small yet delivered a range of nearly 85km of range. The small balloon also saved in helium costs.How did the project go for you? Were there particular challenges?We lost a couple of sondes to heavy rain. We also had a couple of sondes get “stuck” in stable layers. In those cases we needed a bigger balloon and more sonde buoyancy. The output required scripting to get into the format used by the research team. We have asked Windsond to develop an additional output file to remedy that issue.What was your experience with Windsond?Very positive, the developers are quick to help and I have enjoyed working with the sondes and the people behind them.What’s most attractive about Windsond in your mind?ease of use. In fact, for a separate project we trained middle school aged students (12-14 years old) to launch the sondes, collect the data, and send for analysis by the National Weather Service.What are your plans for future campaigns?We hope to continue with funding for the second year of VORTEX-SE. Should our proposal be funded, we will once again be using Windsond.
We thank Mike Brown for the collaboration and the interview! We will add support for the Sharppy data format.
We are happy to tell we are partners for the Navita Space hackaton, to be held in Linköping, Sweden in the weekend of April 22-24. It’s part of the NASA Space Apps Challenge, where volunteers from various backgrounds come up with ideas and solutions to challenges posed by NASA, using their vast public data. The best project goes on to compete against projects from other cities and can win a price and recognition.