Abstract:
Coherent wind doppler lidar (CWDL) is a cost-effective way to estimate wind power
potential at hub height without the need to build a meteorological tower. However, fog and low
stratus (FLS) can have a negative impact on the availability of lidar measurements. Information
about such reductions in wind data availability for a prospective lidar deployment site in advance is
beneficial in the planning process for a measurement strategy. In this paper, we show that availability
reductions by FLS can be estimated by comparing time series of lidar measurements, conducted
with WindCubes v1 and v2, with time series of cloud base altitude (CBA) derived from satellite
data. This enables us to compute average maps (2006–2017) of estimated availability, including
FLS-induced data losses for Germany which can be used for planning purposes. These maps show
that the lower mountain ranges and the Alpine regions in Germany often reach the critical data
availability threshold of 80% or below. Especially during the winter time special care must be taken
when using lidar in southern and central regions of Germany. If only shorter lidar campaigns are
planned (3–6 months) the representativeness of weather types should be considered as well, because
in individual years and under persistent weather types, lowland areas might also be temporally
affected by higher rates of data losses. This is shown by different examples, e.g., during radiation fog
under anticyclonic weather types.
