Data from a GlobalSense system could provide calibration and validation for space-based remote sensing of winds using lidar and carbon dioxide or other trace gases. This capability would extend potential applications to include air quality and greenhouse gas initiatives relating to global climate change. A GlobalSense system can have much broader impacts beyond traditional weather forecasting by measuring acoustic, magnetic, chemical, nuclear, or other parameters of interest for surveillance, reconnaissance, and related applications.
The GlobalSense system features an ensemble of completely disposable, airborne probes, mechanisms to deploy probes, and receiver platforms to gather data from probes. The ultra-compact probes called environmental Motes (eMotes) will integrate micro- and nanotechnology-based components to provide low cost, wireless sensing capability and will function as passive drifters using no active propulsion or flight. eMotes will transmit ultra-low power signals (-20 dB) in one of the industrial, scientific, and medical (ISM) radio bands to avoid expensive licensing requirements. The receiver platforms will contain hardware and software to decode data packets from multiple eMotes within range and store or retransmit the information to other locations.
The eMote design will exploit component miniaturization as well as integration to minimize complexity, cost, size, mass, terminal velocity, and power consumption. With low enough mass and an aerodynamic shape based on bio-inspired shapes (e.g. dandelion or maple seeds), eMotes will be designed to remain airborne for hours or longer depending on atmospheric conditions. Given a nonzero terminal velocity, eMotes can make more measurements if deployed at high altitudes using aircraft or balloons.
The eMote target mass is less than 1 gram with size on the order of centimeters. In addition to minimizing fall speed, these specifications also greatly reduce hazards to people or property as eMotes drift through the air. One potential concern is the environmental impact caused by eMotes once they settle on land or water. The eMotes will not contain materials or components including power sources that pose any significant mechanical, electrical, or environmental hazards. Overall, the environmental issues can be mitigated by designing “biologically inert” eMotes and minimizing the number of components that could have any negative environmental impacts. Ultimately, eMote components will be biodegradable leveraging advances in materials science and organic electronics.
There are two immediate NOAA focus areas that could benefit substantially from the GlobalSense system, namely hurricane and severe storm forecasting. In both areas, there is a need for new systems to measure parameters that cannot be readily obtained with current or even planned observing technology despite enormous progress in both in situ and remote sensing. For example, NOAA's Warn-on-Forecast (WoF) initiative is designed to extend the tornado warning lead-time beyond the plateau reached using Doppler weather radars. The economic and social value of improved warnings is directly linked with saving lives and reducing property damage.
A key challenge of NOAA's WoF initiative is to measure low-level boundary layer fields at space and time scales that are not feasible with any current in situ or remote sensing platforms. eMotes would be ideal to provide these observations for studying the initiation and evolution of supercell thunderstorms. The end goal would be to integrate these data into numerical weather prediction (NWP) models and increase the lead time for severe weather resulting from such storms. Recent events from 2013 in Oklahoma suggest that increased warning lead time especially for violent tornadoes can save lives.
For the hurricane forecast problem, there have been substantial improvements made in track forecasts with errors decreasing steadily during the past decade. Even small improvements in forecasts of land falling hurricanes can have significant economic value given the estimated cost of $1 million to evacuate a linear mile of coastline. However, similar trends in intensity forecasts are not evident and there is substantially less skill in predicting the formation, intensification, fluctuation, and decay of such storms. Part of the problem is due to the lack of routine, four-dimensional observations with sufficient spatial and temporal resolution to initialize hurricane structure and intensity in NWP models. Data from a GlobalSense system could fill such data gaps and improve the accuracy of both hurricane track and intensity forecasts.
Beyond hurricane reconnaissance, operational weather agencies in the U.S. and other countries could deploy eMotes using targeted or adaptive observing strategies for more generalized weather forecasting improvements. Such applications significantly expand the GlobalSense potential especially in parts of the world unaffected by tropical cyclones or tornadoes.
Phase I of the NOAA SBIR grant is focused on component and system design to provide a foundation for prototype development in a Phase II project. The conference presentation will highlight Phase I projects results including simulations of various system components and attributes such as eMote form factor, component geometry, and packaging, receiver hardware and software, and practical deployment options for limited testing in Phase II. It will conclude with plans for building and demonstrating a complete prototype GlobalSense system in the atmosphere featuring hundreds of probes released from balloons or possibly drones as part of a field experiment.