基于风廓线仪的华南地区夏季边界层湍流统计特征研究
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摘要
采用双权重算法,使用2015年6—8月我国东南部业务风廓线雷达资料,通过湍流脉动垂直速度方差和偏度的计算和分析,对晴空和低云主导情况下的边界层湍流特征以及中小尺度局地环流对于边界层湍流的影响进行研究。主要结论如下:(1)晴天情况下垂直速度标准差和垂直速度偏度都具有明显的日变化特征,湍流主要由下垫面加热驱动发展;(2)在低云主导情况下,湍流明显弱于晴天对流边界层的湍流强度,边界层内湍流的发展不仅受地面加热的影响,而且在边界层上部存在明显的自上而下发展的湍流,这主要是由于边界层顶云辐射冷却造成的;(3)除了上述两种情况,边界层湍流发展同时受到局地中小尺度环流或者天气系统的影响,因而呈现出更多的复杂性。
Using a bi-weighting quality control algorithm, three-month(June, July and August) operational wind-profile radar(WPR) data are collected to calculate the vertical velocity standard deviation and skewness in the planetary boundary layer(PBL). The combination of these two statistics is used to investigate the characteristics of the turbulence in PBL under sunny and low-cloud covered conditions, as well as the turbulent structure influenced by local small-scale circulation. The main conclusions are as follows.(1) The operational WPR data clearly discloses significant diurnal variations of the vertical velocity standard deviation and skewness in sunny days, indicating that the typical convective PBL turbulence occurrence is mainly due to surface heating. 2) When low clouds are present around the PBL top, the turbulence intensity is weaker than that in the convective boundary layer(CBL). Usually, there exist two intensive zones of turbulence in the PBL, one is similar to the CBL case which is driven by the surface heating, and another is found to occur from the top of PBL mainly due to the effect of cloud radiative cooling, showing a top-down mechanism.(3) Besides the typical sunny and cloudy cases, about 66.4% of the cases in the three months show much complex turbulence structures, which is influenced by local small-scale circulations or large-scale weather systems.
Using a bi-weighting quality control algorithm, three-month(June, July and August) operational wind-profile radar(WPR) data are collected to calculate the vertical velocity standard deviation and skewness in the planetary boundary layer(PBL). The combination of these two statistics is used to investigate the characteristics of the turbulence in PBL under sunny and low-cloud covered conditions, as well as the turbulent structure influenced by local small-scale circulation. The main conclusions are as follows.(1) The operational WPR data clearly discloses significant diurnal variations of the vertical velocity standard deviation and skewness in sunny days, indicating that the typical convective PBL turbulence occurrence is mainly due to surface heating. 2) When low clouds are present around the PBL top, the turbulence intensity is weaker than that in the convective boundary layer(CBL). Usually, there exist two intensive zones of turbulence in the PBL, one is similar to the CBL case which is driven by the surface heating, and another is found to occur from the top of PBL mainly due to the effect of cloud radiative cooling, showing a top-down mechanism.(3) Besides the typical sunny and cloudy cases, about 66.4% of the cases in the three months show much complex turbulence structures, which is influenced by local small-scale circulations or large-scale weather systems.
引文
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[15]王敏仲,魏文寿,何清,等.风廓线雷达对塔克拉玛干沙漠晴天边界层的探测分析[J].气象, 2012, 38(5):577-584.
[16] QUAN J N, YANG G, ZHANG Q, et al. Evolution of planetary boundary layer under different weather conditions, and its impact onaerosol concentrations[J].颗粒学报(PARTICUOLOGY), 2013, 11(1):34-40.
[17]蒋永波.基于激光雷达的边界层高度探测研究[J].安徽农业科学, 2014, 42(17):5 678-5 679.
[18] LANZANTE J R. Resistant, robust and non-parametric techniques for the analysis of climate data:theory and examples, includingapplications to historical radiosonde station data[J]. Int J Climatol, 1996, 16(11):1 197-1 226.
[19] AND X Z, ZENG Z. A quality control procedure for GPS radio occultation data[J]. J Geophys Res Atmos, 2006, 111(D2):237-253.
[2] EMEIS S. Surface-based remote sensing of the atmospheric boundary layer[M]. Springer Netherlands, 2011.
[3] HARVEY N J, HOGAN R J, DACRE H F. A method to diagnose boundary-layer type using Doppler lidar[J]. Q J Roy Meteo Soc, 2013, 139(676):1 681-1 693.
[4] MOENG C H, WYNGAARD J C. Spectral analysis of large-eddy simulations of the convective boundary layer[J]. J Atmos Sci, 1988, 45(23):3 573-3 587.
[5] MOENG C H, ROTUNNO R. Vertical-velocity skewness in the buoyancy-driven boundary layer[J]. J Atmos Sci, 1941, 47(9):1 149-1 162.
[6] LEMONE M A. Some observations of vertical velocity skewness in the convective planetary boundary layer[J]. J Atmos Sci, 1990, 47(9):1 163-1 169.
[7] MOYER K A, YOUNG G S. Observations of vertical velocity skewness within the marine stratocumulus-topped boundary layer[J]. J AtmosSci, 1991, 48(3):403-410.
[8]江川,沈学顺.基于大涡模拟评估GRAPES模式对对流边界层的模拟性能[J].气象学报, 2013, 71(5):879-890.
[9] HOGAN R J, GRANT A L M, ILLINGWORTH A J, et al. Vertical velocity variance and skewness in clear and cloud-topped boundarylayers as revealed by doppler lidar[J]. Q J Roy Meteor Soc, 2009, 135(640):635-643.
[10] WYNGAARD J C. A physical mechanism for the asymmetry in top-down and bottom-up diffusion[J]. J Atmos Sci, 2010, 44(7):1 083-1 087.
[11] MOENG C H, ROTUNNO R. Vertical-velocity skewness in the buoyancy-driven boundary layer[J]. J Atmos Scis, 1990, 47(9):1 149-1 162.
[12] LENSCHOW D H, WYNGAARD J C, PENNELL W T. Mean-field and second-moment budgets in a baroclinic, convective boundarylayer[J]. J Atmos Sci, 1980, 37(6):1 313-1 326.
[13] LENSCHOW D H, MANN J, KRISTENSEN L. How long is long enough when measuring fluxes and other turbulence statistics?[J]. JAtmos Oceanic Technol, 1994, 11(3):661-673.
[14]何平,马颖,阮征,等.晴空热对流泡的风廓线雷达探测研究[J].气象学报, 2010, 68(2):264-269.
[15]王敏仲,魏文寿,何清,等.风廓线雷达对塔克拉玛干沙漠晴天边界层的探测分析[J].气象, 2012, 38(5):577-584.
[16] QUAN J N, YANG G, ZHANG Q, et al. Evolution of planetary boundary layer under different weather conditions, and its impact onaerosol concentrations[J].颗粒学报(PARTICUOLOGY), 2013, 11(1):34-40.
[17]蒋永波.基于激光雷达的边界层高度探测研究[J].安徽农业科学, 2014, 42(17):5 678-5 679.
[18] LANZANTE J R. Resistant, robust and non-parametric techniques for the analysis of climate data:theory and examples, includingapplications to historical radiosonde station data[J]. Int J Climatol, 1996, 16(11):1 197-1 226.
[19] AND X Z, ZENG Z. A quality control procedure for GPS radio occultation data[J]. J Geophys Res Atmos, 2006, 111(D2):237-253.