High-resolution humidity profiles retrieved from wind profiler radar measurements

Abstract

Abstract. The retrieval of humidity profiles from wind profiler radars has already been documented in the past 30 years and is known to be neither as straightforward and nor as robust as the retrieval of the wind velocity. The main constraint to retrieve the humidity profile is the necessity to combine measurements from the wind profiler and additional measurements (such as observations from radiosoundings at a coarser time resolution). Furthermore, the method relies on some assumptions and simplifications that restrict the scope of its application. The first objective of this paper is to identify the obstacles and limitations and solve them, or at least define the field of applicability. To improve the method, we propose using the radar capacity to detect transition levels, such as the top level of the boundary layer, marked by a maximum in the radar reflectivity. This forces the humidity profile from the free troposphere and from the boundary layer to coincide at this level, after an optimization of the calibration coefficients, and reduces the error. The resulting mean bias affecting the specific humidity profile never exceeds 0.25 g kg −1 . The second objective is to explore the capability of the algorithm to retrieve the humidity vertical profiles for an operational purpose by comparing the results with observations from a Raman lidar.

Inter-comparison of ABL height estimates from different profiling sensors and models in the framework of HyMeX-SOP1

“…The system is manufactured by Degreane (model PCL 1300) and operates in the UHF band with a primary frequency at 1.274 GHz.. A detailed description of the WPR, its specifications and main working parameters, data processing methodologies and delivered 150 geophysical products are illustrated in Saïd et al (2016). The WPR operated almost continuously throughout the duration of HyMeX-SOP1 (Saïd et al, 2018). For the ABL height measurements reported in this paper, the WPR was operated in low mode, with a pulse length of 1μs.…”