Ceilometer and friction velocity observations from Cabauw

This data set contains netcdf files of observed and derived variables from the LD40 ceilometer, as well as the friction velocity (measured with a sonic anemometer). Both instruments are part of the Royal Dutch Meteorology Institute's (KNMI) Ruisdael observatory in Cabauw, The Netherlands. (Some may know this site under its previous name, the CESAR observatory.) These observations are used in the study "Surface-layer wind shear and momentum transport from clear-sky to cloudy weather regimes over land" by Koning et al., 2021. Other observational data used in this study can be found on the KNMI Data Platform: https://dataplatform.knmi.nl/dataset/.<br>1) Data from the LD40 ceilometer (2009-2017), grouped in a tar file per year: ld40_cabauw_[yyyy].tar<br>The tar files contain daily netcdf files of the ld40 backscatter, having a time interval of 15 seconds. File format: cesar_ld40_backscatter_la1_t15s_v1.0_[yyyymmdd].nc<br><br>2) Friction velocity data (2012-2017), 10-minute average, grouped together in one tar file. This data is extracted from the cesar_tower_flux2_lb1_t10_v1.1_[yyyymm].nc. This data only contains data during dry periods and is manually cleaned for these times. <br>

本数据集包含来自LD40云高仪（ceilometer）的观测与衍生变量的网络通用数据格式（NetCDF）文件，以及由超声风速仪（sonic anemometer）测得的摩擦速度。两套仪器均隶属于荷兰皇家气象研究所（Royal Dutch Meteorology Institute, KNMI）位于荷兰卡堡（Cabauw）的Ruisdael观测台，部分使用者或许知晓该站点曾用名CESAR观测台。本观测数据被应用于Koning等人2021年发表的研究论文《陆地晴空至多云天气下的近地层风切变与动量输送》（Surface-layer wind shear and momentum transport from clear-sky to cloudy weather regimes over land）。该研究使用的其他观测数据可于KNMI数据平台获取：https://dataplatform.knmi.nl/dataset/。

1) LD40云高仪数据（2009-2017年）：按年份打包为tar文件，命名格式为ld40_cabauw_[yyyy].tar。每个tar文件内含每日的LD40后向散射NetCDF文件，时间间隔为15秒，文件命名格式为cesar_ld40_backscatter_la1_t15s_v1.0_[yyyymmdd].nc。

2) 摩擦速度数据（2012-2017年）：为10分钟平均值，打包为单个tar文件。该数据提取自cesar_tower_flux2_lb1_t10_v1.1_[yyyymm].nc文件，仅包含干旱时段的数据，并已针对该类时段完成人工质控清洗。