Initial Results from the Southern Edgeworth-Kuiper belt Survey

We present preliminary results of the analysis of the first 500 squaredegrees of the Southern Edgeworth-Kuiper belt Survey, a large sky survey whichran from January 2000 to January 2003 and comprises 2900° in total. Early testspredict that we should discover ～10 bright TNOs in our data, doubling the currentknown population.     

Can in-situ cosmogenic 14C be used to assess the influence of clast recycling on exposure dating of ice retreat in Antarctica?

Cosmogenic nuclide exposure dating of glacial clasts is becoming a common and robust method for reconstructing the history of glaciers and ice sheets. In Antarctica, however, many samples exhibit cosmogenic nuclide ‘inheritance’ as a result of sediment recycling and exposure to cosmic radiation during previous ice free periods. In-situ cosmogenic ¹⁴C, in combination with longer lived nuclides such as ¹⁰Be, can be used to detect inheritance because the relatively short half-life of ¹⁴C means that in-situ ¹⁴C acquired in exposure during previous interglacials decays away while the sample locality is covered by ice during the subsequent glacial. Measurements of in-situ ¹⁴C in clasts from the last deglaciation of the Framnes Mountains in East Antarctica provide deglaciation ages that are concordant with existing ²⁶Al and ¹⁰Be ages, suggesting that in this area, the younger population of erratics contain limited inheritance.     

Minor and trace elements in bornite and associated Cu-(Fe)-sulfides: A LA-ICP-MS studyBornite mineral chemistry

In situ laser ablation inductively-coupled mass spectroscopy (LA-ICP-MS) has been used to provide a baseline dataset on the minor element contents in hypogene bornite and accompanying Cu-sulfides from 12 deposits with emphasis on syn-metamorphic Cu-vein systems in Norway, and skarn, porphyry and epithermal systems in SE Europe.Bornite contains significant concentrations of both Ag and Bi, especially in the vein and skarn deposits studied and has the potential to be a major Ag-carrier in such ores. Concentrations of up to >1 wt.% of both elements are documented. Measured concentrations appear to be independent of whether discrete Ag- and/or Bi-minerals are present within the analyzed sulfide. Where bornite and chalcocite (or mixtures of Cu-sulfides) coexist, Ag is preferentially partitioned into chalcocite over co-existing bornite and Bi is partitioned into the bornite. Bornite is a relatively poor host for Au, which mimics Ag by being typically richer in coexisting chalcocite. Most anomalous Au concentrations in bornite can be readily tracked to micron- and submicron-scale inclusions, but bornite and chalcocite containing up to 3 and 28 ppm Au in solid solution can be documented. Selenium and Te concentrations in bornite may be as high as several thousand ppm and correlate with the abundance of selenides and tellurides within the sample. Selenium distributions show some promise as a vector in exploration, offering the possibility to track a fluid source. Bornite and chalcocite are poor hosts for a range of other elements such as Co, Ni, Ga and Ge, etc. which have been reported to be commonly substituted within sulfides. Hypogene bornite and chalcocite may have significantly different trace element geochemical signatures from secondary (supergene) bornite.     

Mesozoic metallogeny in East China and corresponding geodynamic settings — An introduction to the special issue

The giant East China Mesozoic metallogenic province hosts some of the World’s largest resources of tungsten, tin, molybdenum, antimony and bismuth. Ores of gold, silver, mercury, lead, zinc, copper, uranium and iron are also of major importance. The province and its constituent metallogenic belts or regions (South China; Middle–Lower Yangtze River Valley; East Qinling–Dabie; Interior of North China Craton; Yan-Liao and North-east China) are the products of several pulses of igneous activity and mineralisation between ~240 and ~80 Ma. Each successive stage has produced a distinctive suite of deposits that can be readily related to the geodynamic evolution of the region during the Mesozoic. This geodynamic evolution is linked to a complex series of tectonic events, involving far-field-subduction, plate collisions, crustal thickening, post-collision collapse and rifting.     

Qualitative GIS to Relate Perceptions with Behaviors among Fishers on Risky,Rocky Coasts

This article presents an innovative mixed methodology that integrates qualitative geographic information systes (GIS) methods to expand the examination of space in the context of people’s lived experiences and risk. We emphasize the specific ways in which individuals perceive risk by treating risk as relational. Conceptualizing risk as relational challenges traditional assumptions of risk by rejecting that risk is the combination of physical and social elements. Instead, a relational understanding explores the socioenvironmental interactions that are perceived as hazardous, as they emerge in space. Such claims have long animated risk research, but only recently have methodological advances opened opportunities for relational analyses. Using hazardous coasts as the case, we analyze rock fishers’ risk perceptions and whether those perceptions influence their movement. Analytically, we relate rock fishers’ Global Positioning System movement with participant observations, video, semistructured interviews, and sketch maps anchored to questions focusing on spatial understandings of risk. In doing so, fishers’ perceptions of socioenvironmental stimuli are spatially represented, with sketch mapping as a window into the perception–environment interactions that produce risk. This methodology opens new possibilities for understanding human–environment systems that typically overlook how, where, and for how long risky human–environment interactions are perceived in space, if at all. Key Words: qualitative GIS, relational, risk, risk perception, space.     

Period-luminosity relations for Cepheid variables: from mid-infrared to multi-phase

This paper discusses two aspects of current research on the Cepheid period-luminosity (P-L) relation: the derivation of mid-infrared (MIR) P-L relations and the investigation of multi-phase P-L relations.     

Improved statistical prediction of surface currents based on historic HF-radar observations

Accurate short-term prediction of surface currents can improve the efficiency of search-and-rescue operations, oil-spill response, and marine operations. We developed a linear statistical model for predicting surface currents (up to 48?h in the future) based on a short time history of past HF-radar observations (past 48?h) and an optional forecast of surface winds. Our model used empirical orthogonal functions (EOFs) to capture spatial correlations in the HF-radar data and used a linear autoregression model to predict the temporal dynamics of the EOF coefficients. We tested the developed statistical model using historical observations of surface currents in Monterey Bay, California. The predicted particle trajectories separated from particles advected with HF-radar data at a rate of 4.4?km/day. The developed model was more accurate than an existing statistical model (drifter separation of 5.5?km/day) and a circulation model (drifter separation of 8.9?km/day). When the wind forecast was not available, the accuracy of our model degraded slightly (drifter separation of 4.9?km/day), but was still better than existing models. We found that the minimal length of the HF-radar data required to train an accurate statistical model was between 1 and 2?years, depending on the accuracy desired. Our evaluation showed that the developed model is accurate, is easier to implement and maintain than existing statistical and circulation models, and can be relocated to other coastal systems of similar complexity that have a sufficient history of HF-radar observations.     

Effects of global irrigation on the near-surface climate

Irrigation delivers about 2,600 km³ of water to the land surface each year, or about 2% of annual precipitation over land. We investigated how this redistribution of water affects the global climate, focusing on its effects on near-surface temperatures. Using the Community Atmosphere Model (CAM) coupled to the Community Land Model (CLM), we compared global simulations with and without irrigation. To approximate actual irrigation amounts and locations as closely as possible, we used national-level census data of agricultural water withdrawals, disaggregated with maps of croplands, areas equipped for irrigation, and climatic water deficits. We further investigated the sensitivity of our results to the timing and spatial extent of irrigation. We found that irrigation alters climate significantly in some regions, but has a negligible effect on global-average near-surface temperatures. Irrigation cooled the northern mid-latitudes; the central and southeast United States, portions of southeast China and portions of southern and southeast Asia cooled by ~0.5 K averaged over the year. Much of northern Canada, on the other hand, warmed by ~1 K. The cooling effect of irrigation seemed to be dominated by indirect effects like an increase in cloud cover, rather than by direct evaporative cooling. The regional effects of irrigation were as large as those seen in previous studies of land cover change, showing that changes in land management can be as important as changes in land cover in terms of their climatic effects. Our results were sensitive to the area of irrigation, but were insensitive to the details of irrigation timing and delivery.     

The WAMME regional model intercomparison study

Results from five regional climate models (RCMs) participating in the West African Monsoon Modeling and Evaluation (WAMME) initiative are analyzed. The RCMs were driven by boundary conditions from National Center for Environmental Prediction reanalysis II data sets and observed sea-surface temperatures (SST) over four May–October seasons, (2000 and 2003–2005). In addition, the simulations were repeated with two of the RCMs, except that lateral boundary conditions were derived from a continuous global climate model (GCM) simulation forced with observed SST data. RCM and GCM simulations of precipitation, surface air temperature and circulation are compared to each other and to observational evidence. Results demonstrate a range of RCM skill in representing the mean summer climate and the timing of monsoon onset. Four of the five models generate positive precipitation biases and all simulate negative surface air temperature biases over broad areas. RCM spatial patterns of June–September mean precipitation over the Sahel achieve spatial correlations with observational analyses of about 0.90, but within two areas south of 10°N the correlations average only about 0.44. The mean spatial correlation coefficient between RCM and observed surface air temperature over West Africa is 0.88. RCMs show a range of skill in simulating seasonal mean zonal wind and meridional moisture advection and two RCMs overestimate moisture convergence over West Africa. The 0.5° computing grid enables three RCMs to detect local minima related to high topography in seasonal mean meridional moisture advection. Sensitivity to lateral boundary conditions differs between the two RCMs for which this was assessed. The benefits of dynamic downscaling the GCM seasonal climate prediction are analyzed and discussed.