Preprints
https://doi.org/10.5194/gmd-2022-150
https://doi.org/10.5194/gmd-2022-150
Submitted as: model evaluation paper
06 Jul 2022
Submitted as: model evaluation paper | 06 Jul 2022
Status: a revised version of this preprint was accepted for the journal GMD and is expected to appear here in due course.

Evaluating wind profiles in a numerical weather prediction model with Doppler lidar

Pyry Samuel Sebastian Pentikäinen1, Ewan James O'Connor2,3, and Pablo Ortiz-Amezcua4,5 Pyry Samuel Sebastian Pentikäinen et al.
  • 1Institute for Atmospheric and Earth System Research / Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
  • 2Finnish Meteorological Institute, Helsinki, Finland
  • 3Department of Meteorology, University of Reading, United Kingdom
  • 4Institute of Geophysics, Faculty of Physics, University of Warsaw, Warsaw, Poland
  • 5Andalusian Institute for Earth System Research, Granada, Spain

Abstract. We use Doppler lidar wind profiles from six locations around the globe to evaluate the wind profile forecasts in the boundary layer generated by the operational global integrated forecast system (IFS) from the European Centre for Medium-range Weather Forecasts (ECMWF). The six locations selected cover a variety of surfaces with different characteristics (rural, marine, mountainous urban, coastal urban).

We first validated the Doppler lidar observations at four locations by comparison with collocated radiosonde profiles to ensure that the Doppler lidar observations were of sufficient quality. The two observation types agree well, with the mean absolute error (MAE) in wind speed almost always less than 1 ms-1. Large deviations in the wind direction were usually seen only for low wind speeds, and is due to the wind direction uncertainty increasing rapidly as the wind speed tends to zero.

Time-height composites of the wind evaluation with one-hour resolution were generated and evaluation of the model winds showed that the IFS model performs best over marine and coastal locations, where the mean absolute wind vector error was usually less than 3 ms-1 at all heights within the boundary layer. Larger errors were seen in locations where the surface was more complex, especially in the wind direction. For example, in Granada, which is near a high mountain range, the IFS model failed to capture a commonly occurring mountain breeze, which is highly dependent on the sub grid-size terrain features that are not resolved by the model. The uncertainty in the wind forecasts increased with forecast lead time, but no increase in the bias was seen.

At one location, we conditionally performed the wind evaluation based on the presence or absence of a low-level-jet diagnosed from the Doppler lidar observations. The model was able to reproduce the presence of the low-level-jet but the wind speed maximum was about 2 ms-1 lower than observed. This is attributed to the effective vertical resolution of the model being too coarse to create the strong gradients in wind speed observed.

Our results show that Doppler lidar is a suitable instrument for evaluating the boundary layer wind profiles in atmospheric models.

Pyry Samuel Sebastian Pentikäinen et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Pyry Samuel Sebastian Pentikäinen et al.

Data sets

Doppler lidar wind profiles from Kumpula Finnish Meteorological Institute https://doi.org/10.5281/zenodo.6628968

Doppler lidar wind profiles from Granada University of Granada IISTA-CEAMA https://doi.org/10.5281/zenodo.6628923

Doppler Lidar Horizontal Wind Profiles (DLPROFWIND4NEWS) Atmospheric Radiation Measurement (ARM) user facility https://doi.org/10.5439/1178582

NWP model data (ECMWF IFS) Ewan O'Connor https://doi.org/10.23728/fmi-b2share.b14b1df4a83f4c7dbb54badc2eef607a

Balloon-Borne Sounding System (SONDEWNPN) Atmospheric Radiation Measurement (ARM) user facility https://doi.org/10.5439/1021460

Pyry Samuel Sebastian Pentikäinen et al.

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Short summary
We used Doppler lidar to evaluate the wind profiles generated by a weather forecast model. We first compared the Doppler lidar observations with collocated radiosonde profiles and they agree well. The model performs best over marine and coastal locations. Larger errors were seen in locations where the surface was more complex, especially in the wind direction. Our results show that Doppler lidar is a suitable instrument for evaluating the boundary layer wind profiles in atmospheric models.