Evaluation of an In Situ Atmospheric System for Real Time Weather Monitoring
Authors: Prather J. Craig , Bolt Michael , Harrell Haley , Horton Tyler , Adams Mark L. 
Published: September 2017

Weather affects many aspects of our daily lives from our individual commutes to the global economy. Although much progress has been made in understanding atmospheric physics and weather forecasting, there is still a need for better in situ atmospheric data. Forecasts are based on high performance computer models which solve the differential equations that represent the dynamics of the atmosphere. In all of these models, initial conditions based on the current state of the atmosphere are ingested into the models. The initial conditions are based on data from many sources including remote sensing satellites, ground based weather stations, weather balloons and even aircraft. However, the amount of in situ atmospheric data is very limited and so often times the initial conditions for the models are not truly representative of the current atmosphere. This is especially true for severe storms such as super cell thunderstorms, tornadoes, and hurricanes. Severe weather impacts millions of people every year costing both human life and substantial resources. A better understanding of severe weather will have a significant impact on human safety and infrastructure protection.

Electronics miniaturization and advances in manufacturing such as 3D printing have allowed for the development of low-cost, light-weight probes capable of providing real-time in situ information about the atmosphere which can improve forecasts models and provide a better understanding to atmospheric scientists. The probes provide temperature, relative humidity, pressure, position, and velocity data. MEMS sensors are used to monitor the ambient weather conditions and an on-board GPS receiver provides position information. The sensors are combined with a microcontroller and radio to transmit data back to a receiver on the ground. Power is provided by zinc-air batteries and antennas for both the GPS and data radio are integrated into the package. In order to ensure correct operation of the electronics, 3D printing is used to generate a custom electronics/mechanical package that is both functional and robust while maintaining low weight and high drag coefficient. The desire is for the probes to stay airborne as long as possible without any active means of propulsion or buoyancy.

The probes designed are small, light-weight, and low cost. They can be deployed from aircraft, weather balloons, or dropped directly into a storm. The design of the probes was simulated through CFD to determine the optimal mechanical packaging of the device. The probes have been tested to validate the range of the probes and the accuracy of the measurements. Although most probes can be recovered after testing, designs focus on minimizing the environmental impact of unrecovered probes. This was done by utilizing 3D printing to create custom mechanical packaging for the electronics that is environmentally friendly along with using zinc air batteries which are a less hazardous battery chemistry. The devices have been designed, fabricated, and tested and the results will be presented. This paper will explain the design processes, design decisions, and testing procedures utilized along with the testing results.