Wind Speed Profile Statistics from Acoustic Soundings at a Black Sea Coastal Site

Damyan Barantiev,Ekaterina Batchvarova

doi:10.3390/atmos12091122

Abstract

More than seven years of remote sensing data with high spatial and temporal resolution were investigated in this study. The 20-min moving averaged wind profiles form the acoustic sounding with Scintec MFAS sodar were derived every 10 min. The profiles covered from 30 to 600 m height with vertical resolution of 10 m. The wind speed probability and the Weibull distribution parameters were calculated by the maximum likelihood method at each level and then the profiles of the Weibull scale and shape parameters were analyzed. Diurnal wind speed at heights above 200 m has shown a well-expressed increase in the averaged values during the night hours, while during the day lower wind speeds were observed. The reversal height was explored from spatially and temporally homogenized diurnal wind speed data with applied quadratic functions for better interpretation of the results. In addition, analyses by type of air masses (land or sea air mass) were performed. One of the outcomes of the study was assessment of the internal boundary layer height, which was estimated to 50–80 m at the location of the sodar. The obtained information forms the basis for climatological insights on the vertical structure of the coastal boundary layer and is unique long-term data set important not only for Bulgaria but for coastal meteorology in general.

Highlights

A significant progress has been made over the last years with the technological development of the ground-based instruments for remote sensing measurements of atmospheric characteristics and they have been established as reliable and indispensable tools in a number of innovative scientific methods for the study of the Planetary Boundary Layer (PBL) [1,2,3,4,5,6,7,8,9,10]
Studies show that there is a relationship between the height of the maximum in the profile of the shape parameter and the height of the Internal Boundary Layer (IBL) [4,15,16], but no theoretical connections have been found for this dependence
The extent of “stretch” or “concise” of the Weibull distribution graph is determined by the shape parameter “k”

Summary

Introduction

A significant progress has been made over the last years with the technological development of the ground-based instruments for remote sensing measurements of atmospheric characteristics and they have been established as reliable and indispensable tools in a number of innovative scientific methods for the study of the Planetary Boundary Layer (PBL) [1,2,3,4,5,6,7,8,9,10]. The wind profiles and Weibull distribution parameters profiles are influenced by the air mass transformation processes and depends on the distance to the shoreline in the direction of the airflow. In this case, studies show that there is a relationship between the height of the maximum in the profile of the shape parameter and the height of the IBL [4,15,16], but no theoretical connections have been found for this dependence

Results

Discussion

Conclusion