Greenland's <a href="">ice sheet</a> saw a record <a href="">melt</a> in July 2012.  Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="">clouds</a> which pushed temperatures up above freezing.  For more information see the <a href="">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p>This first global map of <a href="">ocean</a> surface saltiness, released in September 2012 by the NASA Aquarius mission team, shows the distribution of salt in the first 2 cm of the Earth's ocean. <a href="">Salinity</a> variations are one of the main drivers of <a href="">ocean circulation</a>, and are closely connected with the <a href="">cycling of freshwater</a> around the planet. High salinity is seen in the Mediterranean, Atlantic, and the Arabian Sea.<p><small><em>Image courtesy of NASA/GSFC/JPL-Caltech</em></small></p>A new study has found that <a href="/earth/Atmosphere/airpollution_intro.html">pollution</a> from <a href="/earth/Atmosphere/particulates.html">fine particles</a> in the air - mainly the result of burning coal or <a href="/earth/interior/eruptions.html">volcanic eruptions</a> - can shade <a href="/earth/Life/cnidarian.html">corals</a> from sunlight and cool the surrounding water resulting in reduced growth rates.  Coral growth rates in the Caribbean were affected by volcanic aerosol emissions in the early 20th century and by aerosol emissions caused by humans in the later 20th century.  For more information, see the <a href="">press release</a>.<p><small><em>Image courtesy of Toby Hudson (Wikimedia Commons)</em></small></p>An image of Hurricane Sandy taken by the GOES-13 satellite on October 28.  This category 1 <a href="/earth/Atmosphere/hurricane/hurricane.html">hurricane</a> was huge, spanning a horizontal distance of about one-third the US continental landmass.  The storm came onshore in New Jersey, and gradually moved northeast.  The storm disrupted the lives of tens of millions in the eastern US, doing billions of dollars in damage, resulting in over 30 deaths.  Visit the National Hurricane Center's webpage on <a href="">Hurricane Sandy</a> for details.<p><small><em>Image courtesy of NASA</em></small></p>