Use of the Doppler Spectral Width to Improve the Estimation of the Convective Boundary Layer Height from UHF Wind Profiler Observations

Heo, Bok-Haeng; Jacoby-Koaly, Sandra; Kim, Kyung-Eak; Campistron, Bernard; Bénech, B.; Jung, Eunsil

doi:10.1175/1520-0426(2003)020<0408:uotdsw>2.0.co;2

Cited by 38 publications

(34 citation statements)

References 19 publications

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“…6). z i is estimated from UHF as the maximum of the refractive index structure coefficient (Heo et al, 2003;Jacoby-Koaly et al, 2002). From radiosoundings, z i is estimated as the altitude of the maximum relative humidity below 2500 m (this criterion has been shown to be consistent in time and height during the BLLAST experiment; Lothon et al, 2014).…”

Section: Evaluation Of the Simulated Boundary Layermentioning

confidence: 99%

Turbulence vertical structure of the boundary layer during the afternoon transition

et al. 2015

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Abstract.We investigate the decay of planetary boundary layer (PBL) turbulence in the afternoon, from the time the surface buoyancy flux starts to decrease until sunset. Dense observations of mean and turbulent parameters were acquired during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field experiment by several meteorological surface stations, sounding balloons, radars, lidars and two aircraft during the afternoon transition. We analysed a case study based on some of these observations and largeeddy simulation (LES) data focusing on the turbulent vertical structure throughout the afternoon transition.The decay of turbulence is quantified through the temporal and vertical evolution of (1) the turbulence kinetic energy (TKE), (2) the characteristic length scales of turbulence and (3) the shape of the turbulence spectra. A spectral analysis of LES data, airborne and surface measurements is performed in order to characterize the variation in the turbulent decay with height and study the distribution of turbulence over eddy size.This study highlights the LES ability to reproduce the turbulence evolution throughout the afternoon. LESs and observations agree that the afternoon transition can be divided in two phases: (1) a first phase during which the TKE decays at a low rate, with no significant change in turbulence characteristics, and (2) a second phase characterized by a larger TKE decay rate and a change in spectral shape, implying an evolution of eddy size distribution and energy cascade from low to high wave number.The changes observed either in TKE decay (during the first phase) or in the vertical wind spectra shape (during the second phase of the afternoon transition) occur first in the upper region of the PBL. The higher within the PBL, the stronger the spectra shape changes.

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Section: Evaluation Of the Simulated Boundary Layermentioning

confidence: 99%

Turbulence vertical structure of the boundary layer during the afternoon transition

et al. 2015

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“…From the operational viewpoint, however, we have no real-time and high-resolution observations available for daily model-predicted mixing height assessments. Recent studies are trying to replace an existing timeconsuming process to determine mixing depth by developing an objective technique such as using fuzzy logic techniques (Bianco and Wilczak 2002) or spectral width information (Heo et al 2003). But the task still remains to statistically compare the subjective and objective techniques, and it will take some time for the techniques to be readied for operational use.…”

Section: Summary and Concluding Remarksmentioning

confidence: 99%

“…Many observational or technical studies of ABLs have been conducted using wind profilers (Rogers et al 1993;Lemone et al 1999;Campistron et al 2002;Bianco and Wilczak 2002;Heo et al 2003) in the United States and European countries. Also, there have been numerous evaluations of the mixing depth predicted by regional models (Betts et al 1997, Angevine andMitchell 2001) in these continents.…”

Section: Introductionmentioning

confidence: 99%

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

Lee

Kawai

2011

Journal of the Meteorological Society of Japan

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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.

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“…This level is easily detected by the WPRs, since it corresponds to a local maximum in the radar reflectivity profile. Hlim has been used for the past 20 years to monitor the depth of the mixed ABL (Angevine et al, 1994;Heo et al, 2003).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

High-resolution humidity profiles retrieved from wind profiler radar measurements

Saïd

Campistron²,

Girolamo

2018

Atmos. Meas. Tech.

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Abstract. The retrieval of humidity profiles from wind profiler radars has already been documented in the past 30 years and is known to be neither as straightforward and nor as robust as the retrieval of the wind velocity. The main constraint to retrieve the humidity profile is the necessity to combine measurements from the wind profiler and additional measurements (such as observations from radiosoundings at a coarser time resolution). Furthermore, the method relies on some assumptions and simplifications that restrict the scope of its application. The first objective of this paper is to identify the obstacles and limitations and solve them, or at least define the field of applicability. To improve the method, we propose using the radar capacity to detect transition levels, such as the top level of the boundary layer, marked by a maximum in the radar reflectivity. This forces the humidity profile from the free troposphere and from the boundary layer to coincide at this level, after an optimization of the calibration coefficients, and reduces the error. The resulting mean bias affecting the specific humidity profile never exceeds 0.25 g kg −1 . The second objective is to explore the capability of the algorithm to retrieve the humidity vertical profiles for an operational purpose by comparing the results with observations from a Raman lidar.

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Use of the Doppler Spectral Width to Improve the Estimation of the Convective Boundary Layer Height from UHF Wind Profiler Observations

Cited by 38 publications

References 19 publications

Turbulence vertical structure of the boundary layer during the afternoon transition

Turbulence vertical structure of the boundary layer during the afternoon transition

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

High-resolution humidity profiles retrieved from wind profiler radar measurements

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