The Mobile GAUS system components are the same as the standard GAUS components. It is completely self-contained and is can be installed in a minivan, full sized van or pickup truck. The mobility gives the project planner the option to deploy to a specific site make a sounding and if required move to another site for the next sounding. The first sounding can be active and in the air while the vehicle is relocating, although this does affect sounding quality. Sounding site station elevation values are typically taken from a topographic map. If that is not available or if the location is not absolutely certain, a GPS altitude solution is used.
Data communications from the truck to a central operations center can be managed in one of three ways. 1) Data can be transmitted using a cellular phone, 2) it can be sent using a packet radio communication system, or 3) it can be sent using a satellite internet system.
The Mobile GAUS uses the standard GAUS surface instrument package. The configuration of the Mobile GAUS surface instrument package is designed to minimize effects of truck itself on those measurements. Those aspects of the instrumentation which are unique to the Mobile GAUS facility are described in the following sections.
Mobile GAUS Surface Temperature and Humidity Measurement
The entire temperature and humidity sensor, attached to the end of a cross-arm, is mounted on a lightweight moveable tripod. The tripod can be placed up to 15 meters from the truck to remove the measurement from any influence of the truck itself. The cable is deployed as the tripod is positioned for operation.
Mobile GAUS Surface Wind Measurement
The propeller windvane (R.M. Young 05103 Wind Monitor) is mounted on a telescoping pole on the surface met tripod mentioned above. In its fully raised position, the windvane is approximately 6 meters above the ground. The tripod is positioned using a compass for accurate orientation.
Although rarely required for Mobile GAUS operations, radiation measurements can be made. The data collection system has space for a radiation sensor (shortwave incoming only) and can be configured like fixed GAUS to include radiation measurements.
Mobile GAUS Radiosonde Deployment
The Mobile GAUS has everything required for a successful radiosonde launch. Helium for balloon filling is stored in the vehicle and includes a pressure regulator that easily attaches to a helium tank for balloon inflation. The vehicle holds a maximum of three bottles of helium, which is enough for about 15 releases. Sondes and balloons are stored inside the vehicle.
A radiosonde is released from Mobile GAUS in one of two methods. If the winds are calm a balloon can be inflated at the back of the vehicle and tied off with little chance of damage. If the winds get a little stronger the "bare" balloon technique can still be used if the operator fills the balloon just before release and then uses his body to protect the balloon before release. When the wind and weather get too dramatic a bag launcher is used. In this mode, the balloon is inflated while protected and held secure by a heavy vinyl material (the bag) before release.