Assessing the role of alkaline soils on the carbon cycle at a playa site

Alkaline soils occupy approximately 5 % of the Earth’s land surface (7 million km), and this may increase due to the global trend towards increasing desertification, yet the extent to which these soils modulate carbon dynamics on regional and global scales is inadequately studied and poorly understood. Railroad Valley (RRV) playa (Nevada, USA) is a semi-arid playa with highly alkaline soils (pH > 10) and no vegetation. The extreme, alkaline environment and absence of vascular vegetation make RRV an ideal site to investigate the role of physiochemical processes of soil-atmosphere CO₂ exchange. Both field and laboratory investigations were conducted. This work shows how the atmospheric CO₂ mixing ratio decreases at nighttime at RRV playa to a value well below the average global background CO₂ concentration. Laboratory investigations using soil samples collected at RRV playa confirmed that CO₂ uptake by RRV playa soils occurs when temperatures are decreased. Both field and laboratory studies suggest that the alkaline RRV soil acts as a CO₂ reservoir during colder periods, such as at nighttime. These results highlight the importance of investigating carbon dynamics in previously understudied environments. Given how little information is available on the CO₂ flux in desert and semi-arid alkaline ecosystems lacking vegetation, our findings draw attention to these environments as becoming increasingly important for carbon fluxes on regional and global scales.     

Index to Volume 64

China's coal industry has been plagued by fragmentation among thousands of producers, low productivity, environmental damage, and high accident rates. Coal-industry reforms have sought a “strategic westward movement” through which to achieve resource consolidation under larger firms and upgraded production in northern and western China. This article examines Ordos Municipality and Yulin Municipality to assess the role of differently scaled political and economic processes that have driven a regional coal boom. It finds that the regional coal boom in north-central China discloses persistent difficulties in controlling producers and modernizing the sector.     

The altitude of Neptune cloud features from high-spatial-resolution near-infrared spectra

We report on observations of Neptune from the 10-meter W.M. Keck II Telescope on June 17-18 (UT) 2000 and August 2-3 (UT) 2002 using the adaptive optics (AO) system to obtain a spatial resolution of 0.06 arcseconds. With this spatial resolution we can obtain spectra of individual bright features on the disk of Neptune in a filter centered near 2 microns. The use of a gas-only, simple reflecting layer radiative transfer model allows us to estimate the best fit altitudes of 18 bright features seen on these 4 nights and to set a constraint on the fraction of hydrogen in ortho/para equilibrium. On these nights there were three main types of features observed: northern hemisphere features in the range from +30 to −45 degrees; southern hemisphere features in the range from −30 to −50 degrees; and small southern features at −70 degrees. We find that the altitudes of the northern features are in the range from 0.023-0.064 bar, which places them in Neptune's stratosphere. Southern features at −30 to −50 degrees are mainly at altitudes from 0.10 to 0.14 bars. The small features at −70 degrees are somewhat deeper in the upper troposphere, at 0.17 and 0.27 bars. This pattern of features located at higher altitudes in the northern hemisphere and lower altitudes in the south has also been noted by previous observers. The best fits for all the observed spectra give a value of 1.0 for the fraction of hydrogen in ortho/para equilibrium; the value of the helium fraction is less well constrained by the data at 0.24. We suggest that the southern mid-latitude features are methane haze circulated up from below, while the −70° features may be isolated areas of upwelling in a general area of subsidence. Northern bright features may be due to subsidence of stratospheric haze material rather than upwelling and condensation of methane gas. We suggest that convection efficiently transports methane ice clouds to the tropopause in the Southern mid latitudes and thus plays a key role in the stratospheric haze production cycle.     

Spatially resolved STIS spectra of the gravitationally lensed broad absorption line quasar APM08279+5255: the nature of component C and evidence for microlensing

PSR J1806−2125 is a pulsar discovered in the Parkes multibeam pulsar survey with a rotational period of 0.4 s and a characteristic age of 65 kyr. Between MJDs 51462 and 51894 this pulsar underwent an increase in rotational frequency of  Δ ν / ν ≈16×10^-6  . The magnitude of this glitch is ∼2.5 times greater than any previously observed in any pulsar and 16 times greater than the mean glitch size. This Letter gives the parameters of the glitch and compares its properties with those of previously observed events. The existence of such large and rare glitches offers new hope for attempts to observe thermal X-ray emission from the internal heat released following a glitch, and suggests that pulsars which previously have not been observed to glitch may do so on long time-scales .     

Four loss estimates for the Gorkha M7.8 earthquake,April 25, 2015, before and after it occurred

The number of fatalities in the Gorkha M7.8 earthquake of April 25, 2015, has been estimated at four different times as follows. In March 2005, the fatality estimate in this journal was 21,000–42,000 with an assumed magnitude of 8.1 (Wyss in Nat Hazard 34:305–314, 2005). Within hours after this earthquake, the estimated number of fatalities by QLARM was 2000–10,000 using a point source model and M7.9. Four hours later, the estimate was 20,000–100,000, based on a first approximation line source model and assuming children were in school. Children out of school, as this was a weekend day, reduced the fatalities by approximately a factor of two, but was not taken into account for the calculation. The final line source estimates based on M7.8 and M7.9 calculates 800–9300 and 1100–11,200 fatalities, respectively. The official count is about 10,000 fatalities. These estimates were performed using QLARM, a computer tool and world data set on the distribution of people in settlements and containing a model of the buildings present. It is argued here that the loss estimate 10 years before the event being within a factor of 2.1 of the eventual loss count is useful for mitigation planning. With varying quality of information on the source and the attenuation, the estimates of fatalities shortly after the earthquake are accurate enough to be useful for first responders. With full knowledge of the rupture properties and the regional attenuation of seismic waves, the numbers of human losses are estimated correctly.