i-Box (Innsbruck Box) – processed eddy-covariance data: 30-min statistics

<strong>Abstract</strong> The dataset contains eddy-covariance data from five i-Box stations in the Austrian Inn Valley, which have been processed to 30-min statistics. The i-Box is a long-term measurement platform, including a small network of eddy-covariance stations in the lower Inn Valley, to study boundary-layer processes in mountainous terrain. More information about the i-Box can be found at https://www.uibk.ac.at/acinn/research/atmospheric-dynamics/projects/innsbruck-box-i-box.html.en and in Rotach et al. (2017). <strong>Data description</strong> <em>Station locations</em> The present dataset contains processed data from five i-Box stations located in the Austrian Inn Valley. The Inn Valley is an approximately southwest-northeast oriented valley in the western part of Austria, with a depth of about 2000 m and a width of about 2 km at the valley floor. The locations of the sites are shown in the overview figure i-Box_sites.pdf. VF0 is located at the almost flat valley floor. The site is surrounded by grassland and agricultural fields. (47.305°N, 11.622°E, 545 m MSL) SF8 is located at the foot of the north sidewall next to a steep embankment between an agricultural field and a concrete parking lot. (47.326°N, 11.652°E, 575 m MSL) SF1 is located on an almost flat plateau running along the northern valley sidewall. The site is mainly surrounded by grassland and agricultural fields. (47.317°N, 11.616°E, 829 m MSL) NF10 is located on an approximately 10 deg slope on the south sidewall, covered by grassland. (47.300°N, 11.673°E, 930 m MSL) NF27 is located on a steep, grass-covered slope on the south sidewall, with a slope angle of about 25 deg. (47.288°N, 11.631°E, 1009 m MSL) Further information about station locations can be found in Rotach et al. (2017) and Lehner et al. (2021). <em>Temporal coverage</em> The dataset contains processed data between 2014 and 2020. Some instruments were replaced and new instruments were added during this period. Data gaps occur as a result of instrument malfunctions and maintenance. <em>Instrumentation</em> Each station is equipped with at least one sonic anemometer and a gas analyzer. The instrumentation usually consists of a CSAT3 sonic anemometer (Campbell Scientific, USA) and KH20 Krypton hygrometer (Campbell Scientific) or an EC150 open-path infrared gas analyzer (Campbell Scientific). In 2020, several of the instruments were replaced with an Irgason (Campbell Scientific), which combines an open-path infrared gas analyzer with a sonic anemometer. Pressure, air temperature, and humidity used for calculating flux corrections are measured with Setra 278 sensors (Setra Systems, USA) and Rotronic HC2A-S temperature and humidity probes (Rotronic, Switzerland). VF0: CSAT3 and EC150 at 4.0 m, CSAT3 at 8.7 m, CSAT3 and KH20 (until July 2020) or Irgason (since July 2020) at 16.9 m SF8: CSAT3 at 6.1, CSAT3 and KH20 (until September 2020) or Irgason (since September 2020) at 11.2 m SF1: CSAT3 and KH20 (until June 2020) or Irgason (since June 2020) at 6.8 m NF10: CSAT3 and KH20 (until June 2020) or Irgason (since June 2020) at 5.7 m NF27: CSAT3 at 1.5 (since September 2017), CSAT3 and KH20 (until November 2016) or Irgason (since September 2017) 6.8 m Further information about the instrumentation can be found in Rotach et al. (2017), Lehner et al. (2021), and in the ACINN database: VF0: https://acinn-data.uibk.ac.at/pages/i-box-kolsass.html SF8: https://acinn-data.uibk.ac.at/pages/i-box-terfens.html SF1: https://acinn-data.uibk.ac.at/pages/i-box-eggen.html NF10: https://acinn-data.uibk.ac.at/pages/i-box-weerberg.html NF27: https://acinn-data.uibk.ac.at/pages/i-box-hochhaeuser.html <em>Data processing</em> Raw 20-Hz data were quality controlled and rotated into a streamline coordinate system using double rotation before block averaging the data to 30-min statistics, without previous filtering. Flux corrections were applied to the turbulence statistics, including a frequency response correction (Aubinet et al. 2012) with spectral models following Moore (1986), Højstrup (1981), and Kaimal et al. (1972); a sonic heat-flux correction of the vertical heat flux and the temperature variance (Schotanus et al. 1983); a WPL correction of the vertical moisture flux (Webb et al. 1980); and an Oxygen correction of the vertical moisture flux for data from Krypton hygrometers (van Dijk et al. 2003). The quality control procedures include the removal of data during periods of instrument malfunction as indicated by the instruments’ quality flags, a despiking, the removal of data points exceeding 30 m s^-1 for the horizontal wind components, 10 m s^-1 for the vertical wind velocity, and 50 g m³ for water vapor density, and the removal of sonic temperature data outside the range -20 – 40°C. The removed data are replaced with random values drawn from a Gaussian distribution, with its mean and standard deviation calculated over a 30-s data window. Quality flags are based on the criteria described in Stiperski and Rotach (2016): -1: More than 10% of the raw data within the averaging period are replaced during the quality control. 0: More than 90% of the raw data fulfill the quality control criteria. 1: In addition to fulfilling the quality control criteria, the skewness is within the range -2–2 and the kurtosis is less than 8. 2: In addition to the above criteria, the stationarity test by Foken and Wichura (1996) is below 30% and the uncertainty is less than 50% based on Stiperski and Rotach (2016) and Wyngaard (1973) <em>Data files</em> i-Box_sites.pdf contains a map of the i-Box stations. list_variables.pdf contains a list of variable names with a short description. SITENAME_30min.zip contains the processed turbulence statistics, split into yearly files. There is more than one file per year if the instrumentation changed during the year or because of memory restrictions during the processin <em>Acknowledgments</em> Data processing was performed in the framework of the TExSMBL (Turbulent Exchange in the Stable Mountain Boundary Layer) project funded by the Austrian Science Fund (FWF) under grant V 791-N. Data were processed on the LEO HPC infrastructure of the University of Innsbruck. <em>References</em> Aubinet M, Vesala T, D P (eds) (2012) Eddy Covariance. A practical guide to measurements and data analysis. Springer, Dordrecht, DOI 10.1007/978-94-007-2351-1 Højstrup J (1981) A simple model for the adjustment of velocity spectra in unstable conditions downstream of an abrupt change in roughness and heat flux. Boundary-Layer Meteorol 21:341–356, DOI 10.1007/bf00119278 Kaimal JC, Wyngaard JC, Izumi Y, Coté OR (1972) Spectral characteristics of surface-layer turbulence. Q J R M Soc 98:563–589, DOI 10.1002/qj.49709841707 Lehner M, Rotach MW, Sfyri E, Obleitner F (2021) Spatial and temporal variations in near-surface energy fluxes in an Alpine valley under synoptically undisturbed and clear-sky conditions. Q J R M Soc 147:2173–2196, DOI 10.1002/qj.4016 Moore CJ (1986) Frequency response corrections for eddy correlation systems. Boundary-Layer Meteorol 37:17–35, DOI 10.1007/BF00122754 Rotach MW, Stiperski I, Fuhrer O, Goger B, Gohm A, Obleitner F, Rau G, Sfyri E, Vergeiner J (2017) Investigating exchange processes over complex topography—the Innsbruck Box (i-Box). Bull Amer Meteorol Soc 98:787–805, DOI 10.1175/BAMS-D-15-00246.1 Schotanus P, Nieuwstadt FTM, de Bruijn HAR (1983) Temperature measurement with a sonic anemometer and its application to heat and moisture fluxes. Boundary-Layer Meteorol 26:81–93, DOI 10.1007/BF00164332 Stiperski, I. and Rotach, M.W. (2016) On the measurement of turbulence over complex mountainous terrain. Boundary-Layer Meteorology, 159, 97–121. DOI 10.1007/s10546-015-0103-z. Van Dijk A, Kohsiek W, de Bruin HAR (2003) Oxygen sensitivity of Krypton and Lyman-α hygrometers. J Atmos Ocean Technol 20:143–151, DOI 10.1175/1520-0426(2003)020¡0143:OSOKAL¿2.0.CO;2 Webb EK, Pearman GI, R L (1980) Correction of flux measurements for density effects due to heat and water vapour transfer. Q J R M Soc 106:85–100, DOI 10.1002/qj.49710644707 Wyngaard, J.C. (1973). On surface layer turbulence. In D.A. Haugen (Ed.), Workshop on Micrometeorology, American Meteorological Society, pp. 101–150.**摘要** 本数据集包含奥地利因河谷5个i-Box站点的涡动协方差（eddy-covariance）数据，所有数据均已处理为30分钟统计量。i-Box是一套长期观测平台，包含因河谷下游的小型涡动协方差观测站网，用于研究山地边界层过程。有关i-Box的更多信息可访问https://www.uibk.ac.at/acinn/research/atmospheric-dynamics/projects/innsbruck-box-i-box.html.en，或参阅Rotach等人（2017）的研究。 **数据说明** *站点位置* 本数据集包含位于奥地利因河谷的5个i-Box站点的处理后数据。因河谷位于奥地利西部，大致呈西南-东北走向，河谷深度约2000米，谷底宽度约2千米。站点分布详见概览图i-Box_sites.pdf。 VF0位于近乎平坦的谷底，周边为草地与农田，地理坐标为(47.305°N, 11.622°E)，海拔545米（平均海平面高度，MSL）。 SF8位于北坡山麓，紧邻一处陡坡路堤，介于农田与混凝土停车场之间，地理坐标为(47.326°N, 11.652°E)，海拔575米（MSL）。 SF1位于沿北坡延伸的近乎平坦的高原上，周边主要为草地与农田，地理坐标为(47.317°N, 11.616°E)，海拔829米（MSL）。 NF10位于南坡约10°的坡地上，覆盖草地，地理坐标为(47.300°N, 11.673°E)，海拔930米（MSL）。 NF27位于南坡陡峭的草覆盖坡地上，坡度约25°，地理坐标为(47.288°N, 11.631°E)，海拔1009米（MSL）。 站点位置的更多信息可参阅Rotach等人（2017）与Lehner等人（2021）的研究。 *时间覆盖范围* 本数据集包含2014年至2020年的处理后数据。在此期间，部分仪器已更换并新增了部分设备。因仪器故障与维护作业，数据存在缺失时段。 *仪器配置* 每个站点至少配备1台超声风速仪（sonic anemometer）与1台气体分析仪（gas analyzer），常规配置为Campbell Scientific（美国）生产的CSAT3型超声风速仪与KH20型氪湿度计（Campbell Scientific），或EC150型开放式红外气体分析仪（Campbell Scientific）。2020年，部分仪器更换为Irgason（Campbell Scientific），该设备集成了开放式红外气体分析仪与超声风速仪。用于计算通量校正的气压、气温与湿度数据通过Setra 278型传感器（Setra Systems，美国）与Rotronic HC2A-S型温湿度探头（Rotronic，瑞士）采集。 各站点详细配置如下： VF0：4.0米处安装CSAT3与EC150，8.7米处安装CSAT3，16.9米处安装CSAT3与KH20（2020年7月前）或Irgason（2020年7月起） SF8：6.1米处安装CSAT3，11.2米处安装CSAT3与KH20（2020年9月前）或Irgason（2020年9月起） SF1：6.8米处安装CSAT3与KH20（2020年6月前）或Irgason（2020年6月起） NF10：5.7米处安装CSAT3与KH20（2020年6月前）或Irgason（2020年6月起） NF27：2017年9月起，1.5米处安装CSAT3；6.8米处安装CSAT3与KH20（2016年11月前）或Irgason（2017年9月起） 有关仪器配置的更多信息可参阅Rotach等人（2017）、Lehner等人（2021）的研究，以及ACINN数据库： VF0: https://acinn-data.uibk.ac.at/pages/i-box-kolsass.html SF8: https://acinn-data.uibk.ac.at/pages/i-box-terfens.html SF1: https://acinn-data.uibk.ac.at/pages/i-box-eggen.html NF10: https://acinn-data.uibk.ac.at/pages/i-box-weerberg.html NF27: https://acinn-data.uibk.ac.at/pages/i-box-hochhaeuser.html *数据处理* 原始20Hz数据经过质量控制，并采用双旋转法转换至流线坐标系，随后进行块平均得到30分钟统计量，未预先进行滤波。对湍流统计量施加通量校正，包括：基于Moore（1986）、Højstrup（1981）与Kaimal等人（1972）提出的光谱模型的频率响应校正（Aubinet等人，2012）；垂直热通量与温度方差的超声热通量校正（Schotanus等人，1983）；垂直水汽通量的WPL校正（Webb等人，1980）；以及针对氪湿度计观测数据的垂直水汽通量氧气校正（van Dijk等人，2003）。 质量控制流程包括：根据仪器质量标记剔除仪器故障时段的数据、毛刺剔除、剔除水平风速分量超过30 m s⁻¹、垂直风速超过10 m s⁻¹、水汽密度超过50 g m⁻³的数据点，以及剔除-20 ~ 40℃范围外的超声温度数据。被剔除的数据将替换为从高斯分布中抽取的随机值，其均值与标准差通过30秒数据窗口计算得到。 质量标记基于Stiperski与Rotach（2016）提出的标准： -1：平均时段内超过10%的原始数据在质量控制过程中被替换 0：超过90%的原始数据满足质量控制标准 1：除满足上述标准外，偏度处于-2~2范围内，峰度小于8 2：除上述标准外，Foken与Wichura（1996）提出的平稳性检验结果低于30%，且基于Stiperski与Rotach（2016）及Wyngaard（1973）的不确定性小于50% *数据文件* i-Box_sites.pdf包含i-Box站点的分布图。list_variables.pdf包含变量名列表及简要说明。SITENAME_30min.zip包含处理后的湍流统计量，按年度拆分存储。若当年仪器配置发生变更或受处理过程中的内存限制，单年度可能包含多个文件。 *致谢* 本数据集的处理工作依托奥地利科学基金（FWF）资助的TExSMBL（稳定山地边界层湍流交换，Turbulent Exchange in the Stable Mountain Boundary Layer）项目（项目编号V 791-N）开展，数据处理基于因斯布鲁克大学的LEO高性能计算（HPC）基础设施完成。 *参考文献* Aubinet M, Vesala T, D P (eds) (2012) Eddy Covariance. A practical guide to measurements and data analysis. Springer, Dordrecht, DOI 10.1007/978-94-007-2351-1 Højstrup J (1981) A simple model for the adjustment of velocity spectra in unstable conditions downstream of an abrupt change in roughness and heat flux. Boundary-Layer Meteorol 21:341–356, DOI 10.1007/bf00119278 Kaimal JC, Wyngaard JC, Izumi Y, Coté OR (1972) Spectral characteristics of surface-layer turbulence. Q J R M Soc 98:563–589, DOI 10.1002/qj.49709841707 Lehner M, Rotach MW, Sfyri E, Obleitner F (2021) Spatial and temporal variations in near-surface energy fluxes in an Alpine valley under synoptically undisturbed and clear-sky conditions. Q J R M Soc 147:2173–2196, DOI 10.1002/qj.4016 Moore CJ (1986) Frequency response corrections for eddy correlation systems. Boundary-Layer Meteorol 37:17–35, DOI 10.1007/BF00122754 Rotach MW, Stiperski I, Fuhrer O, Goger B, Gohm A, Obleitner F, Rau G, Sfyri E, Vergeiner J (2017) Investigating exchange processes over complex topography—the Innsbruck Box (i-Box). Bull Amer Meteorol Soc 98:787–805, DOI 10.1175/BAMS-D-15-00246.1 Schotanus P, Nieuwstadt FTM, de Bruijn HAR (1983) Temperature measurement with a sonic anemometer and its application to heat and moisture fluxes. Boundary-Layer Meteorol 26:81–93, DOI 10.1007/BF00164332 Stiperski, I. and Rotach, M.W. (2016) On the measurement of turbulence over complex mountainous terrain. Boundary-Layer Meteorology, 159, 97–121. DOI 10.1007/s10546-015-0103-z. Van Dijk A, Kohsiek W, de Bruin HAR (2003) Oxygen sensitivity of Krypton and Lyman-α hygrometers. J Atmos Ocean Technol 20:143–151, DOI 10.1175/1520-0426(2003)020¡0143:OSOKAL¿2.0.CO;2 Webb EK, Pearman GI, R L (1980) Correction of flux measurements for density effects due to heat and water vapour transfer. Q J R M Soc 106:85–100, DOI 10.1002/qj.49710644707 Wyngaard, J.C. (1973). On surface layer turbulence. In D.A. Haugen (Ed.), Workshop on Micrometeorology, American Meteorological Society, pp. 101–150.