Traditionally, the thermodynamic profile of the atmosphere is measured only twice daily by the radiosonde network at an average spacing of 315 km at point locations the US. The frequency of these temperature and humidity measurements are a limitation to a weather model's ability to predict certain weather phenomena that may develop between soundings. With advances in microwave sensing technology, the evolution and behavior of thermal inversions that may occur between soundings can be analyzed in real-time, and assimilated into Numerical Weather Prediction (NWP) models with the goal of improving their overall accuracy. Already in use in some Weather Research and Forecasting (WRF) models around the world, real-time data from passive microwave profiling instruments (MWP) provide a more complete depiction of rapidly evolving temperature and humidity variations in both mesoscale and microscale weather conditions. This paper examines the capabilities of the ground-based microwave profiling instrument in comparison to the radiosonde instrument, and whether there will be a significant benefit to incorporating a network of real-time data in current NWP models used in the US.

Drawbacks still occur within both the potential microwave profiling network and the system itself, and errors will be addressed in a section of this paper. However, assimilating this data from the boundary layer specifically by a joint network of microwave profilers could have the potential for greatly improving forecast skill. By comparing thermodynamic data from the radiosonde to that of the passive microwave profiling instrument in Denver, Colorado, one can examine the time and spatial location of thermal inversions to determine if the profiler shows promise to better depict certain weather conditions that occur around the presence of an inversion. Since the radiosonde is a moving point measurement in contrast to the time integrated vertical profile from the MWP, discrepancies are likely to arise and be investigated. Accuracy of retrievals will be an important factor to consider, since both the microwave retrieval and the radiosondes will be affected due to representative errors. By carefully observing important stability, humidity, and temperature changes that occur on the order of minutes instead of twice daily via radiosonde soundings, the model can generate more accurate initial conditions for dynamic weather events. Thermal inversions are a small but important factor that could contribute to the improvement of the cloud and microphysics scheme in many weather models.

This paper will demonstrate the contribution that a network of continuously monitoring, ground-based profilers will have on the current models. This is part of an on-going investigation of the infrastructure of ground-based MWP thermodynamic retrieval instruments that can be readily accessed, provide significant accuracy, and will be reliable for future research use in the US, and around the world.