2.4.4.3 Monitoring
Accurate monitoring of surface albedo will be required to satisfy industries or governments paying for the coverage in return for thermal credits that can be used to offset their emissions under future climate control treaties. Knowledge of the effectiveness of the cover is also needed for climate modeling and to ensure maintenance to maintain the albedo is performed as needed.
Measurement data to be taken include meteorological, radiometric and surface flux, surface characterization and water vapor data from before and after coverage and from inside and outside the covered area. Monitoring can be carried out using a combination of ground stations consisting of monitors mounted on towers, unmanned aerial vehicles (UAVs) and satellites, both meteorological and from the Earth Observation System (EOS). Terra, an EOS satellite, is equipped with MODIS and ASTER, instrument packages that can measure surface radiation with a resolution of better than 250 m.
2.4.4.4 Maintenance
Repairs to the plastic may be made using patches or spray-on coatings applied by UAVs or ground-based robots. Periodic cleaning to maintain the albedo will be necessary to remove dust and soil deposited by sand storms or dust devils that occur frequently in the deserts of the world. Some preventative measures may be possible such as covering the source of the dust/sand.
To accomplish the cleaning of the plastic, robotic vacuum cleaners or “geovacs” will be developed. They will be self-recharging via solar cells, self-emptying and equipped with albedo monitors to detect when an area is clean enough. GPS and possibly distributed programming will control their position and activities.A commercially available robotic vacuum cleaner, the Roomba®, was evaluated to gain an understanding about the requirements for a geovac. The Roomba, a battery-powered 13.5-inch wide disc shaped machine, uses intelligent navigation technology to operate during a pre-set period. This results in repetitive cleaning of a surface in various patterns.
It uses a combination of roller brushes and a vacuum to pick up both large and small particles. Tests performed on white 4-mil construction film showed that nearly all of fine soil (<177 micron) added was removed, but the wheels and a rubber blade spread the fine dust fraction over the surface, discoloring it and reducing the reflectivity. Based on these tests, a geovac would have to be designed to minimize this problem, most likely by equipping it with tread less balloon tires and using only a vacuum head to remove particles.
