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Validation of the Aeolus L2B Wind Product over the Northern Canada and Arctic

In August 2018, the European Space Agency launched the Aeolus satellite, whose Atmospheric LAser Doppler INstrument (ALADIN) is the first spaceborne Doppler wind lidar to regularly measure global vertical profiles of horizontal line-of-sight (HLOS). This mission has the potential to improve numerical weather prediction over the Arctic where wind observations are sparse. In this study, the Aeolus Level-2B wind product is compared to several other wind products in the Arctic: Ka-band radar and radiosonde measurements at Iqaluit, Nunavut and Whitehorse, Yukon; Environment and Climate Change Canada (ECCC)’s short-range forecast (background, ECCC-B); and the reanalysis product, ERA5, from the European Centre for Medium-Range Weather Forecasts (ECMWF). Periods covered include the early FM-A (2018-09 to 2018-10), early FM-B (2019-08 to 2019-09), and mid-FM-B periods (2019-12 to 2020-01). Broadly, the ECCC-B is most consistent with Aeolus measurements, following bias correction and quality control of the Aeolus data. Notably, consistency is found in the Mie channel from the planetary boundary layer to the lower stratosphere (near surface to 16 km) and in the Rayleigh channel from the troposphere to the stratosphere (2km to 25 km). This consistency is seen in both the near-real time products (2B02/2B06) and the reprocessed data (2B10) with daily updated bias correction. To reduce the standard deviation of HLOS winds, zonal and meridional projections of the HLOS winds are separated, and in all cases Aeolus standard deviations are found to be slightly greater than but generally consistent with those from ECCC-B and ERA5. ECMWF’s estimated error product for Aeolus is found to be coherent with the differences between Aeolus and the other datasets, and thus can be used as a guide for expected consistency. Thus, validated from in-situ measurements in Northern Canada to the pan-Arctic, the new Aeolus product provides a valuable addition to current wind products in regions such as the Arctic Ocean sector where few direct wind observations have been available to date.

Event series  Brewer-Wilson Seminar Series