MetSprite, a 21st century alternative to weather balloons

Atmospheric profiles taken by Radiosondes (weather balloons) are an essential componentof our Earth observation system. These observations are an integral part of the climaterecord and essential for accurate forecasting. In recent decades, satellite platforms havevastly increased the number of remote observations and thereby improved forecast skill.Whilst satellite observations have excellent horizontal resolution, their vertical resolution ispoor and must be complemented by in-situ vertical profiling.

In-situ observations are typically performed by Radiosondes. However, their increasinglyhigh marginal cost (due increased cost of helium & labour) and the pollution inherent intheir operation has prevented the expansion of Radiosonde networks. Globally there are800 Radiosonde sites launching twice per day, with the majority in the northernhemisphere, and only 7 sites in the UK. Whilst advances in computing allow higherresolution forecast models, the observations required to feed these models are struggling tokeep up.

The first few kilometres of the atmosphere, the planetary boundary layer, is where themajority of human activity occurs, and where the weather is most complex and has thehighest socio-economic impact. It is therefore the most critical and challenging region forobservations. A data gap exists in the region above the ground observation network (≤10m)and airliner cruise altitude (10km), which is currently only addressable by the sparseradiosonde network.

Menapia has developed MetSprite to address this data gap. MetSprite is a specialistweather resistant drone with an inbuilt atmospheric sensor package (traceable calibration)and an airframe optimised for vertical profiling. The increased payload and re-usabilityallows multiple advanced sensing systems to be flown on MetSprite, such as for detection ofgases, aerosols, particulates and radiation. A profiling mission can be flown with the push ofa button on the web interface. An inbuilt parachute, autonomy and redundant systemsmake it BVLOS ready, for remote operation and high altitudes.

MetSprite’s cost per profile is over an order of magnitude lower than a Radiosonde, whilstachieving higher fidelity and a wider range of operating conditions. With a faster, moreefficient climb rate it can reach an altitude of over 10km (wind dependent). This rangeallows it to capture the full planetary boundary layer at any point on Earth, and even reachstratospheric heights at high latitudes. Unlike a Radiosonde, the ascent rate and position ofa MetSprite can be controlled, slowing down to capture fine details such as inversion layers.By comparison, the ascent of a Radiosonde is uncontrolled and the first 300m is usuallydiscarded due to sensor settling time.

Initially MetSprite is offered to researchers exploring atmospheric phenomena in greaterdetail. Soon after Menapia will release it’s DiaB solution for full pilotless operation, suitablefor integration in the observation networks of national meteorological organisations andprivate forecasting companies.

Whilst Radiosondes still have the best peak altitude performance, they are out performedby Menapia’s MetSprites on cost, sensing performance, spatial and temporal resolution. Thepotential for the next step change in forecast skill is here.