The THref configuration shown here makes continuous outdoor meteorological measurements at either a fixed site or deployed during a field campaign. It also serves as a high-accuracy reference standard for characterizing the accuracy of RH, T, and P measurements from other sensors. This THref was designed to make a surface "ground check" of the accuracy of individual radiosonde sensors under ambient conditions prior to launch. The accumulation of statistical datasets of such comparisons is useful for radiosonde accuracy assessment, tracking of radiosonde accuracy over time, improved QC/QA of radiosonde measurements, and development and assessment of corrections for mean calibration bias.

The THref data acquisition system uses a Campbell Scientific datalogger, which can either run unattended for long periods or provide real-time data to a PC. The datalogger can sample or process many types of signal input, and it supports complex sampling programs and data processing capabilities. Other instrumentation is readily interfaced with the THref; for example, the serial output of a Paroscientific Met3A station was input to the datalogger to produce an integrated datastream. Multiple dataloggers can be networked to manage the data flow for a large site, and multiple global sites can be managed remotely from a single laptop.

The prototype of the THref is operating at the ARM SGP site. The ARM system was invented by Barry Lesht (Argonne National Lab) and myself, and built and installed at the ARM SGP site by Barry and Mike Ritsche. A 2-year dataset of ARM RS92 radiosonde and surTHref comparisons has been used to characterize the mean RH calibration bias of RS92 radiosondes at the surface, which contributed to the empirical RS92 mean bias correction described elsewhere on this site and by Miloshevich et al. [2009] (see section 2.4 and Figs. 6, 7 and 13). I built the "second-generation" THref system described on this page under contract with NASA/GSFC, where it supports RS92 measurements as part of a mobile atmospheric lidar laboratory that includes Raman lidar, GPS, RS92, THref, and CFH. Data from the first THref deployment to the MOHAVE 2009 campaign at the JPL Table Mountain Facility are shown on this page and used with permission of Dave Whiteman (david.n.whiteman at nasa.gov).