Determination and Climatology of the Cloud Base Height Using Doppler Lidars in the New York State Mesonet Profiler Network

Clouds play a very important role in the radiative heating of the atmosphere and the hydrological cycle; however, large variability of clouds in both time and space has made it difficult for their quantitative observation. Continuous monitoring of the clouds with high accuracy of the cloud base height (CBH) information is a crucial for weather, climate and aerosol studies and modeling, and as well as aviation safety. Taking advantage of high temporal and vertical resolution observations from the active remote sensing instrument, this study evaluates the utility of the ground-based Doppler lidar (DL), as deployed in the New York State Mesonet (NYSM) Profiler Network of 17 stations across New York State, for a reliable monitoring of the CBH. The DL provides vertical profiles of 3D winds and backscatter data in terms of Carrier-to-Noise Ratio (CNR) every ~10s; however, those data are mostly limited with the PBL. The gradient of CNR is evaluated and applied to distinguish clouds from aerosol layers and estimate the CBH. To show the accuracy of the DL-derived CBH, a comparative analysis of CBH with those from the Automated Surface Observing Systems (ASOS) and the City College of New York (CCNY) ceilometers will be presented. In addition, a comprehensive statistical analysis of the one-year data of cloud occurrence frequency and seasonal variation and distribution of CBH from multiple NYSM Profiler Network sites will also be presented. Overall, the results from this study demonstrate the robustness and capability of the DL for real-time observation and monitoring of the CBH that are much needed for the development and improvement of weather and climate model.