## 4 Conclusions
CFSv2, unlike the others, was able to detect a small-scale PL4 with a life-time less than 12 h in the vorticity fields, but it falsely detected two PLs with a lifetime of over 12 h that were not identified either on satellite images or in the satellite-based vector winds. We suspect that, under certain conditions, the atmospheric model component in the CFSv2 analysis generates non-existent mesoscale low-level circulations. Near-surface wind speed distributions within the intense mesocyclonic system (PL2 and PL3) showed that the ERA5, MERRA-2 and CFSv2 data sets well reproduce the PLs median wind speed compared to satellite measurements. The extreme wind speed (95 th percentile) is in reasonable agreement with satellite-based estimates in the initial and decay phases of the mesocyclonic system development. However, during the PLs mature stage--when the storm winds were observed--the ERA5 and MERRA-2 extreme winds are significantly underestimated (up to 8 m/s). CFSv2 reproduced the PL3 intensification in extreme wind values well, but at the PL's peak intensity, the CFSv2 and satellite-based extreme winds discrepancy reached 5 m/s. We believe that the use of the new generation reanalysis data sets for the assessment of intensity and development of PLs over the Chukchi and Beaufort Seas is conditionally justified, but the accurate and reliable representation of severe PLs is still a challenge for both weather and climate services. The advance may lie in the development of a regional reanalysis, taking into account mesoscale atmospheric and oceanic processes in the PA region. Conceptualization and design experiments, [PERSON] and I.G. ; processing and visualization of satellite data, [PERSON]; [PERSON] analyzed the data and wrote the paper; [PERSON] and A.B. visualized and analyzed the data; [PERSON] edited and reviewed the paper. All authors have read and agreed to the published version of the manuscript. This work was supported by the Russian state budget theme 121021500054-3 in the development of technology for multi-sensor satellite sensing of atmospheric and oceanic phenomena and by the Federal Science and Technology Program of the Russian Federation in the areas of environmental improvement and climate change for 2021-2030 (FSTP) within the project <<Rationale for the Climate Monitoring System of the Far Eastern seas and Development of Methods for Monitoring Extreme Weather and Climate Ocean-Related Phenomena Based on Stationary and Mobile Measuring Complexes, as well as Multi-Sensor Satellite Sensing>>. Operational AMSR2 products are available on the Web GIS at [[http://siows.com/](http://siows.com/)]([http://siows.com/](http://siows.com/)) (accessed on 15 August 2022). The AMSR2 Level 1R brightness temperatures are available on the Japan Aerospace Exploration Agency global portal system at [[https://gportal.jaxa.jp](https://gportal.jaxa.jp)]([https://gportal.jaxa.jp](https://gportal.jaxa.jp)) (accessed on 12 June 2022). The measurements of the Advanced Scatterometer (ASCAT) onboard the MetOpA-A/B satellites can be accessed at [[https://podac-tools.jp1.nasa.gov/drive/files](https://podac-tools.jp1.nasa.gov/drive/files)]([https://podac-tools.jp1.nasa.gov/drive/files](https://podac-tools.jp1.nasa.gov/drive/files)) (accessed on 12 June 2022). ERA5, CFSv2 and MERRA-2 hourly fields can be found at [[https://cds.climate.copernicus.eu/](https://cds.climate.copernicus.eu/)]([https://cds.climate.copernicus.eu/](https://cds.climate.copernicus.eu/)) (accessed on 12 June 2022), [[https://nomads.ncdc.noaa.gov/modeldata/](https://nomads.ncdc.noaa.gov/modeldata/)]([https://nomads.ncdc.noaa.gov/modeldata/](https://nomads.ncdc.noaa.gov/modeldata/)) (accessed on 12 June 2022) and [[https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/](https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/)]([https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/](https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/)) (accessed on 12 June 2022), respectively.