WMOD00308 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I vertical by multiplying liquid or vapor depths by the cosine of the offset angle from 900. The grades of typical roads, even in the mountains, seldomly exceed 60, so the correction factor is usually negligible (less than 2% even for a 100 offset) . The radiometer data collection software was modified to allow data sampling at a variety of rates. The maximum rate employs a 4-s integration time which corresponds to a horizontal distance of about 36 m at a truck speed of 20 miles per hour. For mobile operations the longest integration time used is 60 s, which translates to averages over 536 m at 20 miles per hour. In order to monitor data in real time, a portable (lOxlS cm) computer terminal was connected to the radiometer computer and carried in the cab of the truck. This terminal displayed readings of time, outside air temperature, liquid depth, vapor depth, and waveguide temperature. The primary data acquisition and display system of the radiometer was not modified, except that the graphical display program was changed to plot data in 2-h rather than 24-h segments. During the 1991 Utah/NOAA Field Program the radiometer location during mobile operations was determined by noting the time when the truck passed highway mile markers or other landmarks. The locations of the markers and landmarks were then determined with the use of topography maps, or in most cases a portable Global Positioning System (GPS). It is the intention of the DRI to eventually equip the mobile radiometer with a GPS unit and thereby enable continuous monitoring and recording of position directly into the data system. Data Collection: A test of the mobile mode of data collection was made on 13 January 1991 as the radiometer was driven from Reno, Nevada to Mt. Pleasant, Utah. The liquid water trace and cloud conditions for this trip are plotted in Fig. 7. This example demonstrates the primary way in which the mobile 11