The diurnal variation of the planetary boundary layer height (PBLH) over the contiguous United States (CONUS) is examined using Aircraft Meteorological Data Reports (AMDAR) at 54 major airports and the ERA5 reanalysis product. The bulk Richardson number method is used to derive the PBLH at hourly scales from the AMDAR profiles. It is found that the estimated PBLH is sensitive to the value of the critical bulk Richardson number and to the consideration of the surface friction effect, especially under stable and near‐neutral conditions. Parameters constrained by field campaign observations are finally selected to estimate the PBLH. The results reveal that the diurnal climatology of PBLH exhibits seasonal and spatial variations, with greater diurnal variations in spring and summer and in the western regions. It is demonstrated that the traditional twice‐daily radiosonde data may roughly capture the diurnal amplitude of PBLH in the western but not the eastern CONUS. Compared to the AMDAR data, the ERA5 reanalysis product overestimates the daytime PBLH throughout the CONUS by 18–41% and shows an earlier peak time by 1–2 hr in the western regions and a later peak time by 1 hr in the eastern regions.

中文翻译：

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从AMDAR和再分析数据得出的美国连续性行星边界层高度的日气候

使用54个主要机场的飞机气象数据报告（AMDAR）和ERA5再分析产品，检查了连续美国（CONUS）上行星边界层高度（PBLH）的日变化。批量理查森数法用于从AMDAR资料中按小时标度导出PBLH。结果发现，估计的PBLH对临界体积理查森数的值和表面摩擦效应的考虑敏感，特别是在稳定和接近中性的条件下。最后，选择受野战观测约束的参数来估计PBLH。结果表明，PBLH的昼夜气候表现出季节和空间变化，春季和夏季以及西部地区昼夜变化更大。事实证明，传统的每日两次探空仪数据可以粗略地捕获西部CONUS而不是东部CONUS的PBLH的日振幅。与AMDAR数据相比，ERA5再分析产品将整个CONUS的白天PBLH高估了18％至41％，并且在西部地区的峰值时间提前了1-2小时，而在东部地区的峰值时间推迟了1小时。