How do convective cold pools influence the boundary-layer atmosphere near two wind turbines in northern Germany?

Aug 22, 2026

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Rising wind energy in the German grid makes it essential to understand atmospheric processes that disturb turbines and the near-surface boundary-layer environment. Deep convection can drive convective cold pools whose outflow rapidly changes kinematics and thermodynamics beyond the scope of operational weather models. Using 1-minute mast measurements and vertical remote-sensing profiles at the WiValdi research wind park, the study detects and characterizes 120 cold-pool passages over four years.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages25

Reading Time1 h 3 min

AccessFree to download

Introduction

Study motivation and grid impact

Rapid boundary-layer wind changes (wind ramps)

Convection and cold pools as an uncertainty source

[https://doi.org/10.5194/wes-2025-38](https://doi.org/10.5194/wes-2025-38) Preprint. Discussion started: 17 March 2025 􀀍c Author(s) 2025 . CC BY 4.0 License. How do convective cold pools influence the boundary-layer atmosphere near two wind turbines in northern Germany? Jeffrey D. Thayer 1 , Gerard Kilroy 1 , and Norman Wildmann 1 1 German Aerospace Center (DLR), Institute for Atmospheric Physics, Oberpfaffenhofen, Germany Correspondence: Jeffrey D. Thayer ([jeffrey.thayer@dlr.de](jeffrey.thayer@dlr.de)) Abstract. With increasing wind energy in the German energy grid, it is crucial to better understand how particular atmospheric phenomena can impact wind turbines and the surrounding boundary-layer atmosphere. Deep convection is one source of uncertainty for wind energy prediction, with the near-surface convective outflow (i.e., cold pool) causing rapid kinematic and thermodynamic changes that are not adequately captured by operational weather models. Using 1-minute meteorological mast 5 and remote-sensing vertical profile observations from the WiValdi research wind park in northern Germany, we detect and characterize 120 convective cold pool passages over a period of 4 years in terms of their temporal evolution and vertical structure. We particularly focus on variations in wind-energy-relevant variables (wind speed and direction, turbulence strength, shear, veer and static stability) within the turbine rotor layer (34-150 m height) to isolate cold pool impacts that are critical for wind turbine operations. Near hub-height (92 m) during the gust front passage, there are relatively increased wind speeds up 10 to +4 m s −1 in addition to the background flow, a relative wind direction shift up to +15◦ , and increased turbulence strength for a median cold pool. Given hub-height wind speeds lying within the partial load region of the power curve for the detected cases, there is an increase in estimated power of up to 50% which lasts for 30 minutes. We find a ’nose shape’ in relative wind speeds and θv at hub-height during gust front passages, with larger wind direction changes closer to the surface. This manifests as asymmetric fluctuations in positive shear, negative veer, and stability across the rotor layer, with relative variations 15 below hub-height at least twice as large compared with above hub-height and temporarily opposite signs for stability that have complex implications for turbine wakes. Doppler wind lidar profiles indicate that kinematic changes associated with the gust front extend to a height of 650-700 m, providing an estimate for cold pool depth and highlighting that cold pool impacts would typically extend beyond the height of current wind turbines. After the cold pool gust front passage, there is gradually increasing stability, with a decrease in θv to-2 K, a gradual decrease in turbulence strength, and faster recovery of wind speed than wind 20 direction. 1 Introduction With the share of wind energy in the German power grid increasing from 1.7% in 2000 to 34% over the first half of 2024 (BMWK, 2024; Fraunhofer ISE, 2024), the density of wind turbines across Germany is increasing. This indicates that smaller-scale phenomena can impact a greater number of wind turbines, and that the German energy sector is becoming more 25 susceptible to shorter-duration power fluctuations. The stability and balancing of the German electrical grid operates on lead [https://doi.org/10.5194/wes-2025-38](https://doi.org/10.5194/wes-2025-38) Preprint. Discussion started: 17 March 2025 􀀍c Author(s) 2025 . CC BY 4.0 License. times down to 5 minutes, which increases the utility of minute-scale wind power forecasting for energy trading and wind turbine control (Wurth et al., 2019) . Despite the identified importance of short-term wind power forecasting, there are continuing uncertainties with power forecasts. The median annual wind energy production still tends to be overpredicted globally, with uncertain

FAQs

Why are convective cold pools important for wind energy forecasting and turbine operation?

They arise from deep convection and create near-surface cold-pool outflows that rapidly change wind kinematics and thermodynamics, which operational models do not capture well.

What data and observation approach are used in the study?

The analysis combines 1-minute meteorological mast measurements with remote-sensing vertical profile observations from the WiValdi research wind park in northern Germany.

How do cold pools affect wind and turbulence in the turbine rotor layer?

During gust-front passages, median cold pools show increased hub-height wind speeds, wind-direction shifts, and stronger turbulence, which can translate into substantially higher estimated power for about 30 minutes.

Aug 22, 2026

Upload by Mason