Abstract: This data set contains time series of

surface pressure (unnormalized) measured (at station level + 28 m) with a Lambrecht RPT410V pressure sensor [Basic meteorological data]
precipitation sum measured (at station level + 1 m) with an Lambrecht weighing tipping bucket.[Basic meteorological data]
surface radiation flux densities (down-/upward, short-/longwave) and of the radiative surface temperature (at 26 m and 29 m) [Radiation data]
air temperature, relative humidity, wind speed, and wind direction at various levels between 2.2 m and 30.6 m at the 30m-mast. [Tower data]
mean values and variances of the wind components (u, v, w), sonic temperature, humidity and of the turbulent fluxes of momentum, sensible heat, and latent heat at 30.3 m height above ground [Turbulence data]

All these data were measured at Kehrigk forest station (being part of the supersite Lindenberg) above a pine forest canopy during the Field Experiment on Sub-mesoscale Spatio-Temporal Variability in Lindenberg (FESSTVaL) from May to August 2021. The Lindenberg Meteorological Observatory – Richard-Aßmann-Observatory supersite is operated by the German national meteorological service (Deutscher Wetterdienst, DWD). See also: Beyrich, F., W. Adam, 2007: Site and Data Report for the Lindenberg Reference Site in CEOP – Phase I. Offenbach a.M. - Selbstverlag des Deutschen Wetterdienstes: Berichte des Deutschen Wetterdienstes. Nr. 230, 55 pp. (ISSN 0072-4130)

Turbulence data are level-2 data as 30-minute statistics based on 20 Hz sampling organized in daily files. All other data are level-1 data as 1-minute averages (sums) based on 1 Hz sampling organized in daily files.

TableOfContents:

Basic Meteorological Data: rainfall amount; rainfall amount quality flag; air pressure; air pressure quality flag
Radiation Data: surface downwelling shortwave fllux; surface downwelling shortwave flux quality flag; surface upwelling shortwave flux; surface upwelling shortwave flux quality flag; surface downwelling longwave flux; surface downwelling longwave flux quality flag; surface upwelling longwave flux; surface upwelling longwave flux quality flag; surface temperature; surface temperature quality flag
Tower Data: air temperature; air temperature quality flag; relative humidity; relative humidity quality flag; wind speed; wind speed quality flag; wind direction; wind direction quality flag
Turbulence Data: eastward wind u; northward wind v; upward air velocity w; standard deviation of u; standard deviation of v; standard deviation of w; sonic temperature; standard deviation of sonic temperature; wind speed; wind direction; friction velocity; friction velocity quality flag; upward momentum flux; tubulent kinetic energy; surface upward sensible heat flux; surface upward sensible heat flux quality flag; absolute humidity; surface upward water vapor flux; surface upward latent heat flux; surface upward latent heat flux quality flag; signal strength

Technical Info:

Basic Meteorological Data: dimension: 144 x 1; temporalExtent_startDate: 2021-05-01 00:01:00; temporalExtent_endDate: 2021-09-01 00:00:00; temporalResolution: 1; temporalResolutionUnit: minutes; spatialResolution: none; spatialResolutionUnit: none; horizontalResolutionXdirection: none; horizontalResolutionXdirectionUnit: none; horizontalResolutionYdirection: none; horizontalResolutionYdirectionUnit: none; verticalResolution: none; verticalResolutionUnit: meters; horizontalStart: 0; horizontalStartUnit: meters; horizontalEnd: 0; horizontalEndUnit: meters; instrumentNames: rain[e] H3 [precipitation], RPT410V [pressure]; instrumentType: weighing tipping bucket [precipitation], pressure sensor [pressure]; instrumentLocation: both Forst Kehrigk site (station level + 1 m [precipitation], + 28 m [pressure]); instrumentProvider: Lambrecht meteo GmbH [precipitation], Lambrecht meteo GmbH [pressure]
Radiation Data: dimension: 144 x 1; temporalExtent_startDate: 2021-05-01 00:01:00; temporalExtent_endDate: 2021-09-01 00:00:00; temporalResolution: 1; temporalResolutionUnit: minutes; spatialResolution: none; spatialResolutionUnit: none; horizontalResolutionXdirection: none; horizontalResolutionXdirectionUnit: none; horizontalResolutionYdirection: none; horizontalResolutionYdirectionUnit: none; verticalResolution: none; verticalResolutionUnit: meters; horizontalStart: 0; horizontalStartUnit: meters; horizontalEnd: 0; horizontalEndUnit: meters; instrumentNames: CM24 (2 x CM21)[shortwave], DDPIR [longwave], KT15.82D [surface temperature]; instrumentType: precision pyranometer [shortwave], precision infrared radiometer [longwave], radiation pyrometer [surface temperature]; instrumentLocation: all Forst Kehrigk measurement site (26 m & 29 m); instrumentProvider: Kipp&Zonen B.V. [shortwave], Eppley Lab Inc [longwave], Heitronics GmbH [surface temperature]
Tower Data: dimension: 144 x 8 [air temperature & humidity], 144 x 9 [wind speed], 144 x 1 [wind direction]; temporalExtent_startDate: 2021-05-01 00:01:00; temporalExtent_endDate: 2021-09-01 00:00:00; temporalResolution: 1; temporalResolutionUnit: minutes; spatialResolution: none; spatialResolutionUnit: none; horizontalResolutionXdirection: none; horizontalResolutionXdirectionUnit: none; horizontalResolutionYdirection: none; horizontalResolutionYdirectionUnit: none; verticalResolution: variable; verticalResolutionUnit: meters; horizontalStart: 0; horizontalStartUnit: meters; horizontalEnd: 0; horizontalEndUnit: meters; verticalStart: 2.2 [all quantities except wind direction], 30.6 [wind direction]; verticalStartUnit: meters; verticalEnd: 28.3 [air temperature & humidity], 30.6 [wind speed & direction]; verticalEndUnit: meters; instrumentNames: HMP45D [air temperature, humidity],  F460 [wind speed],  model 05103 [wind direction]; instrumentType: Psychrometer [air temperature, humidity], Cup anemometer [wind speed], Wind monitor [wind direction]; instrumentLocation: all Forst Kehrigk measurement site; instrumentProvider: Vaisala Oy [air temperature, humidity], Climatronics Corp. [wind speed], R.M. Young Company [wind direction]
Turbulence Data: dimension: 48 x 1 [turb03: 30.3 m]; temporalExtent_startDate: 2021-05-01 00:30:00; temporalExtent_endDate: 2021-09-01 00:00:00; temporalResolution: 30; temporalResolutionUnit: minutes; spatialResolution: none; spatialResolutionUnit: none; horizontalResolutionXdirection: none; horizontalResolutionXdirectionUnit: none; horizontalResolutionYdirection: none; horizontalResolutionYdirectionUnit: none; verticalResolution: variable; verticalResolutionUnit: meters; horizontalStart: 0; horizontalStartUnit: meters; horizontalEnd: 0; horizontalEndUnit: meters; verticalStart: 30.3; verticalStartUnit: meters; verticalEnd: 30.3; verticalEndUnit: meters; instrumentNames: USA-1 [wind and temperature fluctuations], LI-7500RS [water vapor fluctuations] ; instrumentType:  Sonic anemometer [wind and temperature fluctuations], Infrared gas analyser [water vapor fluctuations]; instrumentLocation: all boundary layer field site (GM) Falkenberg; instrumentProvider: Metek GmbH [wind and temperature fluctuations], LiCor Inc. [water vapor fluctuations]

Methods:

Basic Meteorological Data: Air pressure sensor accuracy is specified by the manufacturer with 0.5 hPa at 20 °C. Quality control includes range tests and an intercomparison versus air pressure measurements at neighbouring sites. Precipitation sensor accuracy is specified by the manufacturer with 0.1 mm or 1 % for precipitation rates < 6 mm / min. Quality control includes a comparison with precipitation measurements at a neighbouring site (and the use of radar images if applicable). Each measured value is accompanied by a quality flag where 0 = data value missing, 1 = good quality, 2 = interpolated or gap-filled by data from an alternative sensor, 3 = dubious quality, 4 = bad quality, 9 = no quality information available.
Radiation Data: Radiation flux sensors are operated in ventilated shields. They are mounted above the forest canopy at 29 m (pyranometers, pyrgeometers) and 26 m (infrared thermometer) above ground, respectively. Mean canopy height was 19 m. The uncertainty is estimated from internal comparisons at ± 5 W/m2 (or 1.5 % - whichever is larger) for shortwave components. The longwave uncertainty is less than ± 5 W/m2. The radiation sensors operated at the forest station are regularly changed and compared versus reference sensors directly traceable to the World Radiometric Reference (WRR) and the World Infrared Standard Group (WISG) for shortwave and longwave radiation, respectively.
For the infrared thermometer, sensor accuracy is specified by the manufacturer with 0.5 K. No quality control has been applied to the level-1 data. Each measured value is accompanied by a quality flag where 0 = data value missing, 1 = good quality, 2 = interpolated or gap-filled by data from an alternative sensor, 3 = dubious quality, 4 = bad quality, 9 = no quality information available.
Tower Data: This data set contains time series of air temperature, relative humidity and wind speed measured at Kehrigk forest station at various levels between 2.2 m and 28.3 m at a 30m-mast. The accuracies of the sensors are specified by the manufacturers as follows: Air temperature: 1/3 DIN IEC 751 Class B // Relative humidity: 2 % (3 % above 90 % relative humidity) // Wind speed: 0.07 m/s or 1 % whichever is greater.
Air temperature and relative humidity are measured in actively aspirated radiation shields of type 43408 (R.M. Young Company). An offset correction is applied to the HMP45D air temperature data based on a regular inter-comparison of the HMP45D temperature measurements against psychrometer temperature measurements during night-time. This offset correction typically is in the range 0.05 - 0.20 K, it has been found to be almost constant in time (variations of less than 0.05 K). Air temperature and relative humidity were measured simultaneously by HMP45D and by an aspirated Frankenberger psychrometer (Th. Friedrichs GmbH). A correction for the HMP45D was derived by minimising the rmsd when compared to the psychrometer data. The coefficients of the non-linear (polynomial) regression model for the FESSTVaL period were based on parallel measurements in April 2021 and in July 2021. Relative humidity values > 100% are set equal to 100%. Due to the construction of the mast there are flow distortion effects on the wind speed measurements for winds from the sector between 35 degrees and 85 degrees. Wind speed values smaller than 0.13 m/s have to be interpreted as calm.

Quality control includes a regular comparison of the air temperature and relative humidity differences of the HMP45D vs. the psychrometer measurements. No further quality control is applied to this level-1 data. Each measured value is accompanied by a quality where 0 = data value missing, 1 = good quality, 2 = interpolated or gap-filled by data from an alternative sensor, 3 = dubious quality, 4 = bad quality, 9 = no quality information available.

Turbulence Data: This data set contains time series of mean values and variances of the wind components (u, v, w), sonic temperature, humidity and of the turbulent fluxes of momentum, sensible heat, and latent heat measured at Kehrigk forest station on the top of a 30m lattice mast above a pine canopy.The accuracies of the sensors forming an eddy-covariance (EC) system are specified by the manufacturers as follows: wind vector components: 0.075 ms-1 or 1.5 % of reading // absolute humidity: <1 % of reading. The EC system at a measuring height of 30.3 m is mounted on top of a lattice mast. Measurements of the sonic are disturbed by lee effects from other sensors (e.g., the LI7500 RS) for wind directions around NNE, i.e., between 355 degrees and 60 degrees. The raw data from the sonic and from the infrared gas analyser (IRGA) based on 20 Hz sampling were processed using the EddyPro V7.0.9 software package provided by LiCor Inc. The following settings were applied:

    Double rotation of the sonic co-ordinate system acc. to Wilczak et al. (2001, Boundary-Layer Meteorol. 99, 127-150)
    Despiking and raw data statistical screening (excluding the test for angle of attack and steadiness of horizontal wind) acc. to Vickers and Mahrt (1997, J. Atmos. Ocean. Technol. 14, 512-526)
    Band pass spectral correction acc. to Moncrieff et al. (1997, J. Hydrol, 188-189, 589-611; 2004, in: Handbook of micrometeorology: a guide for surface flux measurements, eds. Lee, X., W. J. Massman and B. E. Law. Dordrecht: Kluwer Academic, 7-31)
    Buoyancy and crosswind correction acc. to Schotanus et al. (1983, Boundary-Layer Meteorol. 26, 81-93)
    Compensation of density fluctuations acc. to Webb et al. (1980, Quart. J. Roy. Meteorol. Soc. 106, 85-100)
    Quality control of the fluxes includes the stationarity and integral-turbulence-characteristics tests acc. to Mauder et al. (2013, Agric. Forest Meteorol. 169, 122-135), which are implemented in the EddyPro software. These tests are complemented by (i) climatologically-based value range tests, (ii) comparison of net radiation vs. energy fluxes, (iii) validation of ratio of wind speed and friction velocity, and (iv) tests to evaluate the sign of the measured fluxes using gradient measurements (finite differences of the mean variables) provided that both the gradients and the fluxes are not too small. The LI7500 RS signal strength (variable 19) may serve as an additional quality indicator of the IRGA measurement. To validate the quality of the sonic measurements, precipitation measurements are taken into account. All EC system measured quantities such as the wind speed, humidity and temperature are compared to other operational measuring systems in the surrounding area.
    Each derived flux value is accompanied by a quality flag where 0 = data value missing, 1 = bad quality, 2 = dubious quality, 3 = good quality.

Units: (see TableOfContents)

Basic Meteorological Data: kg m-2;1;pa;1
Radiation Data: W m-2;1;W m-2;1;W m-2;1;W m-2;1;K;1
Tower Data: K;1;1;1;m s-1;1;degrees;1
Turbulence Data: m s-1;m s-1;m s-1;m s-1;m s-1;m s-1;K;K;m s-1;degrees;m s-1;1;N m-2;J kg-1;W m-2;1;kg m-3;kg m-2s-1;W m-2;1;1

geoLocations:

BoundingBox:  westBoundLongitude: 14.1221 degrees East; eastBoundLongitude: 14.1223 degrees East; southBoundLatidude: 52.1664 degrees North; northBoundLatitude: 52.1666 degrees North; geoLocationPlace: Germany, UTM zone 33U
Locations:

    Basic Meteorological Data: 52.1817 °N, 13.9525 °E, 49 m above mean sea level, 28.0 m above ground
    Radiation Data: 52.1817 °N, 13.9525 °E, 49 m above mean sea level, 26.0 m to 29.0 m above ground
    Tower Data: 52.1817 °N, 13.9525 °E, 49 m above mean sea level, 2.2 m to 30.6 m above ground
    Turbulence Data: 52.1817 °N, 13.9525 °E, 49 m above mean sea level, 30.3 m above ground

Size: Data (mostly level 1, Turbulence Data level 2) are packed into compressed tar-archives. Their sizes range between 1.4 Mbyte and 19.4 Mbyte.

Format: netCDF

DataSources: Single site ground-based instrument measurements, see "Technical Info" for instruments

Contact: claudia.becker (at) dwd.de; nadja.samtleben (at) dwd.de; frank.beyrich (at) dwd.de

Web page: https://www.cen.uni-hamburg.de/en/icdc/data/atmosphere/samd-st-datasets/samd-st-fesstval/sups-rao-forstkehrigk.html

see also: https://www.cen.uni-hamburg.de/en/icdc/research/samd/observational-data/short-term-observations/fesstval.html

FESSTVaL is funded by the Deutscher Wetterdienst within the Hans-Ertel Centre for Weather Research.