Articles in 2012

The last five years have seen a boom in exploration of the Solar System. Barbara Cohen explains that the biggest gains have been right here on Earth.

A surprising fraction of Earth's element cycling takes place in inland waters. Jonathan Cole suggests that interactions between these water bodies and the terrestrial biosphere are more extensive and interesting than previously thought.

Thirty years ago, the spacecraft Pioneer Venus observed the peak and decline of sulphur dioxide levels above Venus's clouds. Similar observations by Venus Express reveal a surprisingly variable venusian atmosphere.

Record minima in Arctic summer sea ice have been trumping each other. Marika Holland reflects on the likely fate of the northern sea ice cap.

Sea surface temperatures in the eastern equatorial Atlantic Ocean are subject to year-to-year variations. Reanalysis data and model simulations suggest that advection of warm water from north of the Equator can drive some of the warm events.

Wind power inputs at the surface ocean are dissipated through smaller-scale processes in the ocean interior and turbulent boundary layer. Simulations suggest that seafloor topography enhances turbulent mixing and energy dissipation in the ocean interior.

The recovery from the end-Permian mass extinction was slow and prolonged. A temperature reconstruction shows that further biotic crises during the recovery were associated with extreme warmth.

Great Himalayan earthquakes were thought to rarely rupture the surface. Field analyses in Nepal, however, reveal large surface displacements along the main fault bounding India and Asia during at least two historical earthquakes, in 1255 and 1934.

The tropical Atlantic Ocean shows sea surface temperature variability on interannual timescales. Observational and model data suggest that some of this variability can be attributed to the advection of anomalously warm northern subtropical waters toward the Equator.

Tropospheric thunderstorms have been reported to disturb the lower ionosphere, at altitudes of 65–90 km. The use of lightning signals from a distant mesoscale storm to probe the lower ionosphere above a small tropospheric thunderstorm reveals a reduction in ionospheric electron density in response to lightning discharges in the small storm.

Every year, thousands of mesoscale storms (termed polar lows) cross the climatically sensitive subpolar North Atlantic Ocean. High-resolution numerical simulations of the ocean circulation, taking into account the effect of these storms on deep-water formation, suggest that polar lows significantly affect the global ocean circulation.

The recurrence times of great Himalayan earthquakes are difficult to assess because they rarely rupture the surface. Field mapping and ¹⁴C dating of offset fluvial deposits are used to identify two great Himalayan quakes that ruptured the surface along the main plate boundary fault in AD 1255 and 1934.

Changes in continental water storage have been difficult to constrain from space-borne gravity data in regions experiencing both ice melting and glacial isostatic adjustment. Separation of the hydrologic and isostatic signals reveals increases in water storage in both North America and Scandinavia over the past decade.

Sulphate concentrations in the ocean prior to 2.4 Gyr ago were lower than today. The sulphur isotope systematics of 2.7-Gyr-old sulphide deposits suggests that these low concentrations were maintained by a balance between hydrothermal sources and microbial sulphate reduction.

Over 90% of marine species were lost during the end-Permian extinction. Fossil data show that the crisis in China was marked by two distinct phases of marine extinction separated by a 180,000-year recovery period.

A pulse of sulphur dioxide in Venus’s upper atmosphere was observed by the Pioneer Venus spacecraft in the 1970s and 1980s and attributed to volcanism. Recent sulphur dioxide measurements from Venus Express indicate decadal-scale fluctuations in sulphur dioxide above Venus’s cloud tops in an atmosphere that is more dynamic than expected.