Paper on polar lows submitted

Last week I submitted a new paper, where Tom Bracegirdle, Matthias Zahn and I used numerical models to study a “hurricane-like” polar low, to Journal of Geophysical Research–Atmospheres.

The title of the paper is: Re-examining the roles of surface heat flux and latent heat release in a ‘hurricane-like’ polar low over the Barents Sea, and here’s the abstract:

Polar lows are intense mesoscale cyclones that occur at high latitudes in both hemispheres during winter. Their sometimes evidently convective nature, fuelled by strong surface fluxes and with cloud-free centers, have led to some polar lows being referred to as ‘arctic hurricanes’. Idealized studies have shown that intensification by hurricane development mechanisms is theoretically possible in polar winter atmospheres, but the lack of observations and realistic simulations of actual polar lows have made it difficult to ascertain if this occurs in reality. Here the roles of surface heat fluxes and latent heat release in the development of a Barents Sea polar low, which in its cloud structures showed some similarities to hurricanes in satellite images, are studied with an ensemble of sensitivity experiments with WRF, where latent heating and/or surface fluxes of sensible and latent heat were switched off at different stages in the polar low’s life cycle. To ensure that the polar lows in the sensitivity runs did not track too far away from the actual environmental conditions, a technique known as spectral nudging was applied. This was shown to be crucial for enabling comparisons between the different model runs. The results presented here show that: 1) No intensification occurred during the later stages of the simulated polar low; 2) Surface heat fluxes, i.e. air-sea interaction, were crucial processes both in order to attain the polar low’s peak intensity and to maintain its strength; and 3) Latent heat release played a less prominent role in both stages.

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