Some highlights have been picked from papers presented to the next issue of Geophysical Research Letters. Those of interest to astronomy are shown below:
Lightning on Saturn seen for the first time. The probe Cassini saw lightning flashes on Saturn on the 17th of August 2009. The flashes were of comparable energy to those on Jupiter and the Earth and data suggested a flash rate of once per minute. The storm had been in evidence for nine months, much longer than on Earth or Jupiter. Even if it sometimes feels that way…
The recovery of stratospheric ozone levels may end up boosting smog in the troposphere (affecting the seeing). Ozone can leak into the troposphere, creating smog, so as levels increase where we want it, they also increase where we don’t. Furthermore, climate change increases the rate of leakage, causing further problems.
The Kaguya probe (another successful Japanese mission) has reported significant variations in the amounts of Uranium and Thorium in the crust of the far side of the Moon (which is constituted mainly of older highland rock). Unlike the resurfaced, impact basin strewn near-side of the Moon, the far side tells us of conditions closer to the formation of the Moon and the uniformity or not of gamma ray active materials such as uranium and thorium in that crust should be explained in lunar formation models. These variations will help distinguish between the models.
New coupling between stratospheric events and the high altitude ionosphere has been seen. The ionosphere is created mostly by high energy solar radiation and cosmic rays breaking apart atoms and molecules in the thermosphere, creating an ionic component. Because of this massive energy input, it is often assumed that the ionosphere is controlled by solar variability, and to a large extent it is, however it is also known that the upper atmosphere is a ‘harbinger’ of climate change, showing warming trends. A new study has shown that amid the massive solar induced variability, there is also a measurable effect created by changes in the lower atmosphere via planetary waves.