Polar lows (PLs) are intense mesoscale weather systems that often cause severe storm winds in the Nordic Seas but were considered as being exceedingly rare in the Pacific Arctic region before sea ice decline. Here, we explore four PLs observed on 18–22 October 2017 in the Chukchi and Beaufort Seas—an area with an exceptionally sparse observation network. The study is based on the combined use of the satellite microwave measurements, as well as infrared imagery, the ERA5, MERRA-2 and NCEP-CFSv2 reanalysis data sets. An unusually strong PLs pair developed near the marginal ice zone during a marine-cold air outbreak in anomalously low sea ice extent conditions. PLs pair moved southward as a mesocyclonic system called the “merry-go-round”, under the upper-level tropospheric vortex with a cold core. Multi-sensor satellite measurements show that, in the mature stage, a PL pair had near-surface wind speeds (W) close to hurricane force—over 30 m/s. Comparison analysis of W distributions within the strongest PL showed that all reanalysis data sets reasonably reproduce the PL median wind speed but underestimate its extreme values by 15–23%. The reanalysis data sets detected only two PLs with horizontal scales of over 220 km. Tracks of identified PLs for all data sets are in good agreement with the ones obtained from satellite images capturing the main features of the mesoscale weather system propagation. For the track of the strongest PL event, ERA5 exhibited the most accordance with satellite observations with a tracking error of 50–60 km.

A sudden stratospheric warming (SSW) is a large-scale meteorological disturbance that usually takes place in the arctic region. In the present research, the formation, characteristics, intensity and duration of SSW events over the North polar area in 2015-2016 winter months are studied by using the satellite passive microwave, reanalysis (ERA-Interim) and radiosonde time series. The MTVZA-GY microwave radiometer data onboard Meteor-M N 2 were collected before, during and after the SSW events. The measurements obtained by 10 microwave channels in the range between 52.8 and 57.6 GHz characterize the air temperature variations in the troposphere and stratosphere up to about 42-45 km. The detailed study was carried out over several circular areas in the vicinity of radiosonde stations located mainly in and around Greenland. Comparison of MTVZA-GY, ERA5 and radiosonde time series allowed to monitor the evolution of the SSWs, estimate their temporal characteristics, horizontal and vertical gradients of air temperature.

In the present article, cold-air outbreak (CAO) and polar low (PL) events were examined over the Chukchi Sea during low sea ice extent of the basin in the November-December period, 2015. An analysis of weather events was performed using multisensor satellite measurements, the NCEP Climate Forecast System, version 2 (CFSv2), and Arctic System Reanalysis, version 2 (ASR2). The CFSv2 data showed that the most intense cold advection occurred at the 1000-900 hPa boundary layer. It was shown that CAO had been developing from November 30 to December 6 and was accompanied by the sea surface wind speed exceeding 20 m/s and rapid formation and drift of sea ice. Analysis of the sea ice response to the CAO showed fast freezing of the Chukchi Sea for seven days indicating excessive heat loss of the water basin. In addition, significant increase in the open and very open ice areas was observed. These areas could be exposed to excessive cold atmosphere, releasing heat into the atmosphere. PL events have been identified during intensive mesocyclogenesis over the sea during 15-17 November. Weather conditions were characterized by the values of wind speed reaching 15-17 m/s and dry air with total water vapor content (5-7 kg/m²). Analysis of the synthetic aperture radar image revealed the position and horizontal size of the meso-α-cyclone, the fine structure of the mesoscale frontal system of the PL forming meso-γ-vortices, and the wave-like line of the horizontal wind shear in the local convergence zone. The representation of PL events in sea level pressure and near-surface wind speed fields from the ASR2 and CFSv2 datasets was ambiguous. However, the satellite-based and CFSv2 wind speeds better agreed for high-wind conditions.

Application of satellite passive microwave sensing for the retrieval of key climatic parameters in the Barents Sea is considered. Fields of surface wind, atmosphere water vapor content and cloud liquid water content were found from MTVZA-GY radiometer onboard the Meteor-M N1 satellite and AMSR2 onboard the GCOM-W1 satellite with the use of original algorithms. The fields are in a good agreement with the ancillary remote and in situ measurements, which follows from the analysis of the evolution of the extra tropical and polar cyclones and cold air outbreaks with storm winds leading to intense air-sea interaction, and the formation and drift of sea ice.

A review of the current state of research in the field of numerical modelling and forecasting of cold-air outbreaks over the ocean at high latitudes and associated mesoscale circulations is...

Mesoscale cyclonic activity is one of the characteristics of the cold season in the Japan Sea. High winds and precipitation accompanying intense mesoscale cyclones (MCs) disturb transport and fishery operations in the sea and small sizes and fast development hinders their forecast and detection. Satellite data of visible, infrared, passive and active microwave sensors serve as a valuable source of data on MCs. They are used for their detection, tracking, evaluating of quantitative characteristics of the atmospheric and oceanic parameters during MC life cycle, getting statistical estimates as well as for checking and improving the results of modeling. Case studies demonstrate the efficiency of the multisensory approach and the leading role of microwave sensing for mesoscale cyclone investigation.