Mixing Depth Estimation from Operational JMA and KMA Wind-Profiler Data and its Preliminary Applications: Examples from Four Selected Sites

Abstract

In this study, mixed layer (ML) height information is extracted from the range-corrected signal-to-noise ratio (SNR) data of wind profilers operated by the Japan Meteorological Agency (JMA) and the Korea Meteorological Administration (KMA). The altitude where the maximum backscattered power is received by a wind profiler is regarded as ML height. Four sites (Kumagaya and Mito in Japan; Munsan and Gangneung in Korea) were tested on clear sky days, which were chosen using a sunshine ratio. The ML height information obtained was utilized to analyze the spatiotemporal variations of ML heights over Japan and to qualitatively evaluate the model mixing depth predicted by a KMA regional numerical weather prediction model. The frequency of the wind profiler is 1.36 GHz (1.29 GHz for sites in Korea), and the temporal resolution of the SNR data is 10 min. In the vertical, the operating resolutions are 300 m for the sites in Japan and 70 m for Korea.The quantitative analysis of the mixing depths estimated by JMA shows day-to-day, seasonal, and spatial variations in the measured mixing depths. Comparison with nearby radiosonde observations, as well as surface station and satellite observations, is conducted. The estimated ML height tended to be somewhat high in the early morning presumably due to the minimum detectable range and a residual layer (RL) effect. Mean ML heights at the Kumagaya site in July and October 2001 show a seasonal difference of about 500 m. The sea breeze effect can be seen in ML heights at the Mito site located near the sea coast. On the other hand, the evaluation of model-predicted ML heights against KMA SNR data reflected the nonlocal K-profile boundary layer scheme's well-known feature of having faster development with greater depth for an ML. It is proposed in this paper that the ML heights estimated from the Munsan and Gangneung sites can be applied to the observational analysis of mixing depths and be employed as an auxiliary tool for evaluating model ML heights on an operational basis.

Diurnal course analysis of the WRF-simulated and observation-based planetary boundary layer height

“…The constants were statistically derived from radiosounding measurements. The wind-profiler measurements allowed the use of height-corrected (Lee and Kawai, 2011) signal-to-noise ratio (SNR) to define the top of the PBL as the maximum of SNR (Angevine et al, 1994). This method was modified when stable stratification was found with radiometric measurements; the maximum was searched for only as long as the SNR increased with height.…”

Relation between the Atmospheric Boundary Layer and Impact Factors under Severe Surface Thermal Conditions

“…Adopting the numerical model, Zhao [27] demonstrated that in summer the contribution of sensible heat to the development of CBL in arid areas in western China is greatest, but it is hard to explain only by this. However, Han et al [28] and others [5,29,30] believed that the RML has significant impact on the formation of thick CBL in desert.…”

“…In addition, it plays an important role in cloud formation, rain production, and other feedback in the coupled system [1,2]. To get more data, Eddy Covariance (EC, hereinafter) System was used widely for measuring surface fluxes of momentum, sensible heat, and water vapour in the field experiments [3], which are key to the understanding and prediction of other processes taking place within the ABL [4,5]. The thickness of ABL is also one of the important physical parameters of atmospheric numerical model and environmental assessment [6].…”

“…According to the study by Gamo et al (1994), the atmosphere with thick CBL often has a weakly stable and nearly neutral stratification (RML) in desert in the whole; and Flamant et al [16] found that the RML in Sahara can be maintained for a whole day sometimes. Many other scientists hold the view that the existence and maintenance of RML exert a key influence on the development of CBL [5,12,17,18]. Compared with the Sahara, the Northwest China area is far from the sea and characterized by more complicated topography and drier climate, which makes ABL extremely special [19].…”

Spatial and Temporal Variation in PBL Height over the Korean Peninsula in the KMA Operational Regional Model

“…To identify the ML top, there have been several methods for which radiosondes, wind profilers, and ceilometer/light detection and ranging (LIDAR) were utilized (e.g., [9][10][11][12][13][14]). These kinds of techniques to extract PBLH information have been also applied over the Korean Peninsula to surface flux [15][16][17], radiosonde [18,19], LIDAR [20], and wind profiler [21] data. Most of the researchers analyzed characteristics of PBLH at one location over the peninsula and obtained several important results.…”