Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock

Background

Livestock play an important role in carbon cycling through consumption of biomass and emissions of methane. Recent research suggests that existing bottom-up inventories of livestock methane emissions in the US, such as those made using 2006 IPCC Tier 1 livestock emissions factors, are too low. This may be due to outdated information used to develop these emissions factors. In this study, we update information for cattle and swine by region, based on reported recent changes in animal body mass, feed quality and quantity, milk productivity, and management of animals and manure. We then use this updated information to calculate new livestock methane emissions factors for enteric fermentation in cattle, and for manure management in cattle and swine.

Results

Using the new emissions factors, we estimate global livestock emissions of 119.1 ± 18.2 Tg methane in 2011; this quantity is 11% greater than that obtained using the IPCC 2006 emissions factors, encompassing an 8.4% increase in enteric fermentation methane, a 36.7% increase in manure management methane, and notable variability among regions and sources. For example, revised manure management methane emissions for 2011 in the US increased by 71.8%. For years through 2013, we present (a) annual livestock methane emissions, (b) complete annual livestock carbon budgets, including carbon dioxide emissions, and (c) spatial distributions of livestock methane and other carbon fluxes, downscaled to 0.05 × 0.05 degree resolution.

Conclusions

Our revised bottom-up estimates of global livestock methane emissions are comparable to recently reported top-down global estimates for recent years, and account for a significant part of the increase in annual methane emissions since 2007. Our results suggest that livestock methane emissions, while not the dominant overall source of global methane emissions, may be a major contributor to the observed annual emissions increases over the 2000s to 2010s. Differences at regional and local scales may help distinguish livestock methane emissions from those of other sectors in future top-down studies. The revised estimates allow improved reconciliation of top-down and bottom-up estimates of methane emissions, will facilitate the development and evaluation of Earth system models, and provide consistent regional and global Tier 1 estimates for environmental assessments.

     

The X-ray eclipse of OY Car resolved with XMM–Newton: X-ray emission from the polar regions of the white dwarf

We present the XMM–Newton X-ray eclipse light curve of the dwarf nova OY Car. The eclipse ingress and egress are well resolved for the first time in any dwarf nova placing strong constraints on the size and the location of the X-ray emitting region. We find good fits to a simple linear eclipse model, giving ingress/egress durations of  30 ± 3 s (Δφ_orb= 0.0054 ± 0.0005)  . Remarkably, this is shorter than the ingress/egress duration of the sharp eclipse in the optical, as measured by Wood et al. (1989) and ascribed to the white dwarf  (43 ± 2 s)  . We also find that the X-ray eclipse is narrower than the optical eclipse by  14 ± 2 s  , which is precisely the difference required to align the second and third contact points of the X-ray and optical eclipses. We discuss these results and conclude that X-ray emission in OY Car arises most likely from the polar regions of the white dwarf.
Our data were originally reported by Ramsay et al. (2001b) , but they did not make a quantitative measurement of eclipse parameters. We have also corrected important timing anomalies present in the data available at that time.     

Cassini UVIS observations of Jupiter's auroral variability

The Cassini spacecraft Ultraviolet Imaging Spectrograph (UVIS) obtained observations of Jupiter's auroral emissions in H₂ band systems and H Lyman-α from day 275 of 2000 (October 1), to day 81 of 2001 (March 22). Much of the globally integrated auroral variability measured with UVIS can be explained simply in terms of the rotation of Jupiter's main auroral arcs with the planet. These arcs were also imaged by the Space Telescope Imaging Spectrograph (STIS) on Hubble Space Telescope (HST). However, several brightening events were seen by UVIS in which the global auroral output increased by a factor of 2-4. These events persisted over a number of hours and in one case can clearly be tied to a large solar coronal mass ejection event. The auroral UV emissions from these bursts also correspond to hectometric radio emission (0.5-16 MHz) increases reported by the Galileo Plasma Wave Spectrometer (PWS) and Cassini Radio and Plasma Wave Spectrometer (RPWS) experiments. In general, the hectometric radio data vary differently with longitude than the UV data because of radio wave beaming effects. The 2 largest events in the UVIS data were on 2000 day 280 (October 6) and on 2000 days 325-326 (November 20-21). The global brightening events on November 20-21 are compared with corresponding data on the interplanetary magnetic field, solar wind conditions, and energetic particle environment. ACE (Advanced Composition Explorer) solar wind data was numerically propagated from the Earth to Jupiter with an MHD code and compared to the observed event. A second class of brief auroral brightening events seen in HST (and probably UVIS) data that last for ∼2 min is associated with auroral flares inside the main auroral ovals. On January 8, 2001, from 18:45-19:35 UT UVIS H₂ band emissions from the north polar region varied quasiperiodically. The varying emissions, probably due to auroral flares inside the main auroral oval, are correlated with low-frequency quasiperiodic radio bursts in the 0.6-5 kHz Galileo PWS data.     

The Origin of Glitches in Pulsars—Phase Oscillation between Anisotropic Superfluid and Normal State of Neutrons in Neutron Stars

Considering neutron star heating by magnetic dipole radiation from 3PF2 super-fluid neutron vortices inside the star, we propose a neutron phase oscillation model between the normal neutron Fermi fluid and the 3PF2 superfluid neutron vortices at the transition temperature of T_(trans) = (2-3)×108 K. With this model we can qualitatively explain most of the observations on pulsar glitches up to date.     

Recovery of the long lost minor planet (1179) Mally (Astronomisches Rechen-Institut — Mitteilungen Serie B)

The orbit of minor planet (1179) Mally which was supposed to be almost hopelessly lost since its discovery in 1931 is rediscussed. Based on a remeasurement of the original Heidelberg plates, two alternative search ephemerides for the perihelion opposition 1986 have been computed. The object was found on the line of variation very near to the predicted position. The recovery was confirmed by the discovery of additional images on UK Schmidt and ESO Schmidt plates as well as on Palomar Sky Survey exposures. There are no further identities of this faint planet among more than 100,000 reported observations of minor planets in this century. Improved elements based on seven apparitions 1931–1986 are given.     

Enhanced nondestructive characterization of ordinary chondrites using complex magnetic susceptibility measurements

Ordinary chondrites have previously been nondestructively characterized using bulk magnetic susceptibility, broadly reflecting their Fe-Ni alloy content. We seek to expand the information that can be recovered from magnetic susceptibility by using the University of Toronto Electromagnetic Induction Spectrometer (UTEMIS) to measure the complex magnetic susceptibility tensor of 20 ordinary chondrites samples in addition to 16 Gao–Guenie (H5) chondrites at 35 frequencies from 90 Hz to 64 kHz, at variable low applied field strengths <10 A m⁻¹. Following removal of the field-dependent component of susceptibility, frequency dependence, in- and out-of-phase components, and bulk magnetic susceptibility were interpreted. Most meteorites showed no frequency-dependent in-phase responses, but had a frequency-dependent out-of-phase response attributed to eddy currents induced in conductive minerals. Greater in- and out-of-phase frequency dependence correlated with lower fayalite content in olivine and was, in turn, inversely proportional to Fe-Ni alloy content. The uncertainty in the UTEMIS measurements ranges from approximately 0.05% for low-frequency in-phase measurements to a maximum of 3% for low-frequency out-of-phase measurements. This uncertainty level was far lower than the intra-meteorite variability for the Gao–Guenie suite suggesting inhomogeneity at scales of approximately 10 g.     

Marsh-creek connectivity: Fish use of a tidal salt marsh in Southern California

Salt marsh habitats influenced by southern California's mixed, semi-diurnal tides are, on average, accessible to fishes less than 16% of the time. However, five species (four natives, one oxotic) and a variety of juvenile and adult size classes were collected on the marsh surface during a year-long sampling from June 1997 through June 1998 at Sweetwater Marsh National Wildlife Refuge on San Diego Bay.Fundulus parvipinis andGillichthys mirabilis were the most abundant fish species using the marsh. Analyses of their guts revealed that the marsh surface provides a rich foraging area for fishes on high spring tides.F. parvipinnis with marsh access consumed six times as much food as fishes restricted to creek habitats (on a g-food g-fish^?1 basis) and also fed on additional prey types. Because the salt marsh is an important foraging area for fishes, we recommend that restoration projects (especially those intended to mitigate lost fish habitat) include vegetated areas with interconnecting tidal creeks.     

A relation between abrasiveness and quartz content for some Coal Measures sediments

Conclusions 1. For a limited range of Coal Measures sediments, it has been shown that a good relation exists between the abrasiveness of the rocks and their quartz content.2. In this instance it was not possible to make any correlation with cutter wear, but it would be expected from the above result that the higher the quartz content of the rock the greater would be the wear on the cutters.