In spite of an expected decline in convective activity following the 2007 equinox of Uranus, eight sizable storms were detected on the planet with the near-infrared camera NIRC2, coupled to the adaptive optics system, on the 10-m W. M. Keck telescope on UT 5 and 6 August 2014. All storms were on Uranus's northern hemisphere, including the brightest storm ever seen in this planet at 2.2 μm, reflecting 30% as much light as the rest of the planet at this wavelength. The storm was at a planetocentric latitude of ∼15∘N and reached altitudes of ∼330 mbar, well above the regular uppermost cloud layer (methane-ice) in the atmosphere. A cloud feature at a latitude of 32∘N, that was deeper in the atmosphere (near ∼2 bar), was later seen by amateur astronomers. We also present images returned from our HST ToO program, that shows both of these cloud features. We further report the first detection of a long-awaited haze over the north polar region.
@article{arxiv.1501.01309,
title = {Record-breaking Storm Activity on Uranus in 2014},
author = {Imke de Pater and L. A. Sromovsky and P. M. Fry and Heidi B. Hammel and Christoph Baranec and Kunio Sayanagi},
journal= {arXiv preprint arXiv:1501.01309},
year = {2015}
}