Adaptability evaluation of boundary layer schemes for simulation of sea and land breeze circulation in the west coast of the Yellow Sea

Highlights

• Sea-land breeze profile was systematically investigated by 3D wind LiDAR and simulated.

• Thermodynamic mechanism schemes were significant in the simulation circulation.

• The schemes of GBM, MYNN2 and YSU were more suitable in the sea-land breeze area.

• The simulation bias of wind profile decreased with the height, the smallest near 800-1000 m.

• Conversion time bias was due to thermal convection, turbulence, entrainment in the schemes.

Abstract

In the study, a three dimensional Doppler Wind Lidar placed at a coastal city Rizhao in west coast of Yellow sea was used to evaluate the wind field simulated by ten different planetary boundary layer parameterization schemes (PBLS) in the Weather Research and Forecasting model. It is found that the characteristics of the simulated wind field are very sensitive to the boundary layer parameterization schemes used in the model, especially for the sea-land breeze (SLB). Analysis shows that Grenier-Bretherton-McCaa (GBM), Mellor-Yamada Nakanishi and Niino Level 2.5 (MYNN2), and Yonsei University (YSU) produced more realistic results of the three dimensional wind field, as well as the occurrence time, duration and heights of SLB. This is because the entrainment effect is adopted in the GBM scheme, which improves the radiation process between the ground and the atmosphere and ensures the accuracy of turbulent diffusion calculation caused by the differences of temperature and humidity in coastal area. The YSU scheme introduces a local gradient correction term, so that the non-local thermals brings the surface hot air to the middle and upper part of the boundary layer. This process increases the turbulent mixing induced by thermal forcing in the simulation of SLB. The MYNN2 scheme specifies the relationship between the length scale and buoyancy, turbulence scale and surface layer in turbulent kinetic energy equation, and introduces a set of closure parameters representing buoyancy and shear. However, the disadvantages of this scheme are that the influence of the underlying surface is not considered in detail, and the entrainment heat flux at the top of the convective boundary layer is underestimated.

Introduction

Sea-land breeze (SLB) circulation is the main characteristics of the wind field in the atmospheric boundary layer in coastal areas. It plays a vital role in regulating temperature, precipitation and pollutant diffusion. The difference between land and sea surface temperature determines the development of SLB. The sea breeze circulation conveys a relatively cold and wet air mass from the sea surface to the land, thus creating a thermal inner boundary layer (TIBL) between the sea and the warm land surface, in order to carry out vertical mixing of air. In the planetary boundary layer, there is a turbulent vertical exchange between the free atmosphere and the underlying surface of the earth, which has a great impact on the development and evolution of the weather system. Today, with the increasing attention to environmental research, the study on the structure and change law of SLB circulation is of great significance, such as the layout of possible pollution sources, the prediction of pollutant emissions and the improvement of air quality in this region.

Observation and numerical simulation are two main methods for studying sea and land winds. As early as the 1950s, there appeared many means by conducting space three-dimensional observation of sea and land winds such as aircraft and ships. At present, remote sensing observation method such as satellite and radar can be used directly observing or retrieving the three-dimensional structure characteristics of wind direction and wind speed change law of sea and land winds. (Fisher, 1960; Simpson et al., 1977; Banta et al., 1993; Azorin-Molina and Chen, 2009). Through a large number of observations and analysis of SLB circulation, researchers calculated and studied various theoretical models based on the quantitative theory of circulation dynamics and in combination with the characteristics of local topography and coastline trend. The development of SLB models has gone through several stages, including linear theoretical model (Haurwitz, 1947), nonlinear equation model (Pearce, 2010), and two-dimensional sea land wind model (Estoque, 1961) with the emergence of computers, and then numerical three-dimensional model simulation of SLB (Pielke, 1974; Kikuchi et al., 2007; Anthes et al., 1982; Arritt, 1993; Xu et al., 1996). At present, high-resolution mesoscale numerical models are mostly used to simulate the SLB cases under typical weather conditions (Mass et al., 2000) and the plume diffusion process in coastal areas (Lin et al., 2001). The relationship between pollutants released from coastal areas and TIBL can be further studied (Liu and Chan, 2002; Stunder and Sethuraman, 1985; Jie et al., 2018; Yang et al., 2022).

In mesoscale numerical simulation, the choice of planetary boundary layer parameterization schemes (PBLS) is closely related to the numerical simulation and prediction accuracy of boundary layer wind field (Dalu and Pielke, 1993; Mazzaro et al., 2017; Ferrero et al., 2018; Yang et al., 2019; Reddy et al., 2020). The Monin-Obukhov function is used in PBLS to parameterize near-layer variables, and different PBLS adopt different M-O function forms. Therefore, the characteristics, assumptions, formulas and applicable conditions of different boundary layer schemes also differ significantly (Stull, 1988; Garratt, 1993). In this study, we use the high-resolution Doppler Wind Lidar (DWL) boundary layer three-dimensional wind data, combined with the model simulation results, in order to find PBLS suitable for simulating the wind field under the similar climate background in this observation area.

The SLB observation area in this study is located in Rizhao, Shandong Province, China. It is in the middle latitude area, adjacent to the Yellow Sea in the East and about 4.3 km away from the West Coast of the Yellow Sea. The South and North are respectively connected with Haizhou Bay and Jiaozhou Bay, and the North-South coastline is relatively straight. The inland is composed of plains and hills. The terrain is high in the middle and low around. The average altitude is close to sea level, and the highest altitude is 706 m.

According to the observation facts over the years, the SLB circulation along the Rizhao coast is very obvious. Previously, Zhuang et al. (2005) used the data of ground observation stations and made statistics on the impact of the seasonal and daily changes of SLB on the temporal and spatial distribution of meteorological elements such as temperature and precipitation. Ma,Y. et al. used DWL continuously observed and studied the SLB cycle structure on the West Bank of the Yellow Sea for the first time, by analyzed the key elements of sea land wind in this area, such as development height, transformation duration, wind speed, wind shear, etc. On this basis, the exploration of simulation tests of SLB circulation for various boundary layer schemes were carried out in this area for the first time.