CROSSINN (Cross-valley flow in the Inn Valley investigated by dual-Doppler lidar measurements) - ACINN Doppler wind lidar data sets (SL88, SLXR142)

ABSTRACT

The data sets found here were collected with ACINN's Doppler wind lidars SL88 and SLXR142 in the Inn Valley, Austria, from 1 Aug 2019 to 13 Oct 2019, within the CROSSINN field campaign (Cross-valley flow in the Inn Valley investigated by dual-Doppler lidar measurements). The goal of the campaign was to study the multi-scale three-dimensional flow structure and the impact of the flow on the mountain atmospheric boundary layer (MoBL) structure and evolution across the Inn Valley. Further details of the campaign can be found in Adler et al. (2020a).

DATA SET DESCRIPTION

1. Spatial coverage and locations

Measurements were collected during the CROSSINN field campaign in the Inn Valley, Austria. The focus of the campaign was located at a mild valley curvature approximately 20 km northeast of Innsbruck. ACINN’s two Doppler wind lidars SL88 and SLXR142 were deployed next to ACINN’s i-Box flux tower in Kolsass (see Rotach et al. 2017 for a description of the i-Box). The exact lidar locations are:

• SL88: 47.305205°N / 11.622219°E / 546.8 m MSL
• SLXR142: 47.305177°N / 11.622245°E / 548.5 m MSL

2. Temporal coverage

The CROSSINN field campaign officially lasted from 1 Aug 2019 to 13 Oct 2019. However, the SL88 data set contains the period from 14 Jun to 10 Oct 2019 (1 Hz data and VAD products). The SLXR142 data set covers the same period from 14 Jun to 10 Oct 2019 for the 1 Hz data, but only the period from 21 Jun to 10 Oct 2019 for the VAD products.

3. Instrument details

General

Measurements were taken with two scanning Doppler wind lidars, model Stream Line (SL88) and Stream Line XR (SLXR142), manufactured by HALO Photonics. Available here are profiles of radial velocity and backscatter data of plan position indicator (PPI) scans and vertical stares at 1 Hz as well as derived products (vertical wind profiles). Additionally, range height indicator (RHI) scans are available for the SLXR142 lidar for the early phase of the experiment. Each single profile (also called "ray") of the 1-Hz data represents a one-second average over 15000 pulses for the SL88 lidar and an average over 10000 pulses for the SLXR142 lidar.

Data correction and data products

We provide so-called corrected "level 1" data. The data correction includes an adjustment of the azimuth angle due to instrument misalignment (a corrected azimuth angle of 0° corresponds to true north) and a correction of the range gate distance (only necessary for SLXR142). Python source code used to apply these corrections and to do derive products, i.e., to calculate the vertical wind profiles based on the velocity azimuth display (VAD) technique, can be found in Haid (2021a,b).

CSM scan mode and effect on azimuth and elevation angle

All PPI and RHI scans were performed as continous motion scans (CSM mode). For a continuous motion scan, the scanner moves continuously as data are acquired. Therefore, the azimuth (elevation) angle continuously changes for PPI (RHI) scans over the pulse averaging interval of one second to create one profile at a  1 Hz frequency. It is important to notice, that *the azimuth and elevation angles in the 1-Hz data files provided here represent the starting point of the pulse averaging interval*. The same applies to the time stamp. Depending on the application, these angles may have to be corrected by the data user by shifting the azimuth and elevation angle by half an increment (i.e., \(\alpha_\mathrm{corr} = \alpha_\mathrm{orig} + \Delta \alpha/2\)). For deriving vertical wind profiles based on the VAD technique (see data products below), this correction has already been applied.

4. Data file structure

File format

Provided are data in netCDF format as well as quick-look figures in PNG format. File names contain date and time information in UTC. The following wildcard characters are used in the file examples below: yyyy - year; mm - month, dd - day; HH - hour, MM - minute, SS - second. NetCDF data files and quick-look figures are zipped together into the following zip files.

Zip files

SL_88_data_corrected_yyyymm.zip contains netCDF files of corrected SL88 data, one zip file for each month.

SL_88_data_products.zip contains netCDF files of SL88 data products.

SL_88_quicklooks.zip contains PNG files of SL88 quick-look figures.

SLXR_142_data_corrected_yyyymm.zip contains netCDF files of corrected SLXR142 data, one zip file for each month.

SLXR_142_data_products.zip contains netCDF files of SLXR142 data products.

SLXR_142_quicklooks.zip contains PNG files of SLXR142 quick-look figures.

SL88 corrected data

User1_88_yyyymmdd_HHMMSS_l1.nc contains a full-rotation PPI scan at 70° elevation angle performed in CSM mode at 1 Hz with 36 m range gate length and a rotation speed of 6°/s. Data of each PPI scan is stored in a separate file. Notice the definition of azimuth and elevation angle for CSM scans described in section 3.

Stare_88_yyyymmdd_HH_l1.nc contains vertical stare measurements conducted in between two PPI scans and aggregated together in one file for each hour.

SL88 data products

sl88_yyyymmdd_vad.nc contains vertical profiles of the three-dimensional wind vector derived from PPI scans based on the VAD technique. Each vertical profile is based on a single full-rotation PPI scan conducted at a 70° elevation angle about once per minute (see corrected data above). Profiles are aggregated together for each day in a separate file.

SL88 quick-look figures

Quicklook_rawdata_Lidar_88_yyyymmdd.png is an overview figure showing uncorrected (“raw”) data at 1 Hz for a complete day. It is useful for assessing data availability, quality and scan procedure.

SL_88_yyyymmdd_vad.png is an overview figure showing vertical profiles of horizontal and vertical wind derived from PPI scans based on the VAD technique (see data products above) for a complete day. It is useful for assessing the predominant wind regimes.

SLXR142 corrected data

User5_142_yyyymmdd_HHMMSS_l1.nc contains various different PPI scans conducted at three different elevation angles during the last 30 minutes of each hour. There are three different types of files recognizable by the minute in the file name (wildcard character MM): files with MM=30 and MM=58 contain single full-rotation PPI scans at 70° elevation angle. Files with MM=32 contain 12 full-rotation PPI scans alternating between 4° and 7° elevation angle over a period of about 26 minutes. All PPI scans were performed in CSM mode at 1 Hz with 36 m range gate length and a rotation speed of 3°/s. Notice that the scan procedure was different before 01 August 2019 and also included RHI scans in along-valley direction. Also notice the definition of azimuth and elevation angle for CSM scans described in section 3.

Stare_142_yyyymmdd_HH_l1.nc contains vertical stare measurements conducted at 1 Hz during the first 30 minutes of each hour and aggregated together in one file for each hour.

SLXR142 data products

slxr142_yyyymmdd_vad.nc contains vertical profiles of the three-dimensional wind vector derived from PPI scans based on the VAD technique. Each vertical profile is based on a single full-rotation PPI scan conducted at a 70° elevation angle about once per half hour (see corrected data above). Profiles are aggregated together for each day in a separate file.

SLXR142 quick-look figures

Quicklook_rawdata_Lidar_142_yyyymmdd.png is an overview figure showing uncorrected (“raw”) data at 1 Hz for a complete day. It is useful for assessing data availability, quality and scan procedure.

SLXR_142_yyyymmdd_vad.png is an overview figure showing vertical profiles of horizontal and vertical wind derived from PPI scans based on the VAD technique (see data products above) for a complete day. It is useful for assessing the predominant wind regimes.

5. Software, publications and related data sets

The ACINN Doppler wind lidar data sets were processed with Python software published by Haid (2021a,b). CROSSINN data sets of KIT can be found in Adler et al. (2021b-d). The CROSSINN field experiment is described in Adler et al. (2021a). First analyses of CROSSINN data can be found in Adler et al. (2021a) and Ladstätter (2020).

6. Contact

Contact alexander.gohm (at) uibk.ac.at for any questions regarding the data set.

7. References

Adler, B., A. Gohm, N. Kalthoff, N. Babić, U. Corsmeier, M. Lehner, M. W. Rotach, M. Haid, P. Markmann, E. Gast, G. Tsaknakis, G. Georgoussis, 2021a: CROSSINN: A Field Experiment to Study the Three-Dimensional Flow Structure in the Inn Valley, Austria. Bulletin of the American Meteorological Society, 102, E38-E60, https://doi.org/10.1175/BAMS-D-19-0283.1

Adler, B., N. Babić, N. Kalthoff, A. Wieser, 2021b: CROSSINN (Cross-valley flow in the Inn Valley investigated by dual-Doppler lidar measurements) - KITcube data sets [WLS200s]. Data set. KITopen. https://doi.org/10.5445/IR/1000127847

Adler, B., N. Babić, N. Kalthoff, A. Wieser, 2021c: CROSSINN (Cross-valley flow in the Inn Valley investigated by dual-Doppler lidar measurements) - KITcube data sets [CHM 15k, GRAW, HATPRO2, Mobotix, Photos]. Data set. KITopen. https://doi.org/10.5445/IR/1000127577

Adler, B., N. Babić, N. Kalthoff, U. Corsmeier, C. Kottmeier, C. Mallaun, 2021d: CROSSINN (Cross-valley flow in the Inn Valley investigated by dual-Doppler lidar measurements) - Aircraft data set [FDLR]. Data set. KITopen. https://doi.org/10.5445/IR/1000127862

Haid, M., 2021a: marenha/CROSSINN: First release (Version v1.0.0). Zenodo. http://doi.org/10.5281/zenodo.4601014

Haid, M., 2021b: marenha/doppler_wind_lidar_toolbox: CROSSINN release (Version v1.1.0). Zenodo. http://doi.org/10.5281/zenodo.4600972

Ladstätter, P. J., 2020: Vertical structure of the atmospheric boundary layer in the Inn Valley during CROSSINN. Master's thesis, University of Innsbruck, 114 pp. https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-68131

Rotach, M. W., I. Stiperski, O. Fuhrer, B. Goger, A. Gohm, F. Obleitner, G. Rau, E. Sfyri, J. Vergeiner, 2017: Investigating Exchange Processes over Complex Topography: The Innsbruck Box (i-Box). Bulletin of the American Meteorological Society, 98, 787-805, https://doi.org/10.1175/BAMS-D-15-00246.1