NEXRAD Based Convective Boundary Layer Height Compared To Multiple Instruments

NEXRAD BASED CONVECTIVE BOUNDARY LAYER HEIGHT

COMPARED TO MULTIPLE INSTRUMENTS

Delia Tatiana Della Porta

Department of Electrical Engineering, University of Maryland Baltimore County

Dr. Belay Demoz

Department of Physics, University of Maryland Baltimore County

ABSTRACT

An assessment of observations of the Convective Boundary Layer (CBL) height from multiple instruments is presented with the purpose of establishing validation of the same phenomena with different instruments. This study takes advantage of the measurements that each instrument provides to derive the CBL height. Raman Lidar, 915 MHz wind profiler, Radiosonde, AERI/Raman CBL height estimate from inversion, and WSR-88D (NEXRAD) datasets are analyzed. Raman lidar water vapor mixing ratio and aerosol scattering ratio (asr) approximate the CBL height by estimating an aerosol-based mixing layer height; a wind profiler measures wind speed/direction and its returned signal to noise ratio (snr) depicting the zones where diurnal turbulence exists, thus indirectly measuring the CBL height; a radiosonde observes a full in-situ thermodynamic profile of the column of air along its path of ascend directly describing the CBL height; a product of inversion from AERI/Raman also provides an estimate of CBL height, and NEXRAD’s differential reflectivity detects the region where a Bragg Scattering layer is observed by the reflection of the NEXRAD S-band RADAR signal on the air masses, such a layer is associated with the location of the top of the CBL. The main purpose of this study is to demonstrate that the NEXRAD observations of the CBL height agree with the convective boundary layer height estimated by the rest of listed instruments and may be used as an anchor for nationwide PBL estimation activity. Automated Signal and Image Processing algorithms are presented to process archived NEXRAD, wind profiler, and Raman Lidar datasets to detect the area that describes the CBL height. The daily radiosonde measurements were used as truth. The experiment shows that the NEXRAD’s CBL height estimation is corroborated by the other instruments, thus the WSR-88D is capable of producing a valid CBL height estimate.