Boundary Layer Characteristics Over Complex Terrain in Central Taiwan: Observations and Numerical Modeling
Journal
Journal of Geophysical Research: Atmospheres
Journal Volume
127
Journal Issue
2
Date Issued
2022
Author(s)
Abstract
The development of the atmospheric boundary layer and flow circulation becomes complicated over complex terrain. A field campaign involving the acquisition of tethersonde, ozonesonde and 10-m meteorological tower observations was conducted during September 2–8, 2013, over the Puli Basin located in the mountainous area of central Taiwan to investigate the evolution of the planetary boundary layer (PBL) and flow circulation. In addition, numerical simulations using the Weather Research and Forecasting (WRF) model were performed to examine the three-dimensional air flow variations. Analysis of the tethersonde data indicated a well-mixed boundary layer structure and a steady westerly flow over the Puli Basin during the daytime that became further enhanced in the afternoon. The 600-m resolution WRF model simulation showed that the enhanced wind flow in the afternoon was due to the inland penetration of the onshore sea breeze, which also transported high concentrations of O3 from the western metropolitan area into the basin. During the nighttime, a stable boundary layer formed, above which a nocturnal low-level jet formed throughout the campaign period in the Puli Basin. The WRF model is able to reproduce the general variations in the wind flows and thermal structures. Furthermore, the diagnostic PBL height estimated based on the critical Richardson number provides an enhanced understanding of the evolutionary characteristics of the PBL over complex terrain. ? 2022. American Geophysical Union. All Rights Reserved.
Subjects
complex terrain
high-resolution weather simulation
nocturnal low-level jet
planetary boundary layer
sea breeze intrusion
tethersonde
boundary layer
metropolitan area
numerical model
observational method
ozonesonde
Richardson number
Puli Basin
Taiwan
Type
journal article