Knowing into oblivion: Clearing wastelands and imagining emptiness in Vietnamese New Urban Zones

Lands cleared for Vietnamese New Urban Zones are commonly described as ‘wastelands’ (??t hoang) in need of development. But clearing these lands in Vietnam's densely populated urban areas requires evicting large numbers of urban residents. How is it possible to render populated spaces as empty wastelands? This paper juxtaposes new ethnographic research in Ho Chi Minh City against historical scholarship on Vietnamese concepts of ‘clearing the wasteland’ and colonial civilizing projects of mise en valeur. In doing so, the article describes these concepts as parallel legitimizing strategies that effectively enable developers and planners to render previously occupied and utilized lands as empty, uninhabited wastelands. The article shows that the same narrative structure used in these earlier contexts is used to justify current urban development projects.     

Time-series analysis of multi-resolution optical imagery for quantifying forest cover loss in Sumatra and Kalimantan,Indonesia

Monitoring loss of humid tropical forests via remotely sensed imagery is critical for a number of environmental monitoring objectives, including carbon accounting, biodiversity, and climate modeling science applications. Landsat imagery, provided free of charge by the U.S. Geological Survey Center for Earth Resources Observation and Science (USGS/EROS), enables consistent and timely forest cover loss updates from regional to biome scales. The Indonesian islands of Sumatra and Kalimantan are a center of significant forest cover change within the humid tropics with implications for carbon dynamics, biodiversity maintenance and local livelihoods. Sumatra and Kalimantan feature poor observational coverage compared to other centers of humid tropical forest change, such as Mato Grosso, Brazil, due to the lack of ongoing acquisitions from nearby ground stations and the persistence of cloud cover obscuring the land surface. At the same time, forest change in Indonesia is transient and does not always result in deforestation, as cleared forests are rapidly replaced by timber plantations and oil palm estates. Epochal composites, where single best observations are selected over a given time interval and used to quantify change, are one option for monitoring forest change in cloudy regions. However, the frequency of forest cover change in Indonesia confounds the ability of image composite pairs to quantify all change. Transient change occurring between composite periods is often missed and the length of time required for creating a cloud-free composite often obscures change occurring within the composite period itself. In this paper, we analyzed all Landsat 7 imagery with <50% cloud cover and data and products from the Moderate Resolution Imaging Spectroradiometer (MODIS) to quantify forest cover loss for Sumatra and Kalimantan from 2000 to 2005. We demonstrated that time-series approaches examining all good land observations are more accurate in mapping forest cover change in Indonesia than change maps based on image composites. Unlike other time-series analyses employing observations with a consistent periodicity, our study area was characterized by highly unequal observation counts and frequencies due to persistent cloud cover, scan line corrector off (SLC-off) gaps, and the absence of a complete archive. Our method accounts for this variation by generating a generic variable space. We evaluated our results against an independent probability sample-based estimate of gross forest cover loss and expert mapped gross forest cover loss at 64 sample sites. The mapped gross forest cover loss for Sumatra and Kalimantan was 2.86% of the land area, or 2.86 Mha from 2000 to 2005, with the highest concentration having occurred in Riau and Kalimantan Tengah provinces.     

Efficient scheme for the shallow water equations on unstructured grids with application to the Continental Shelf

In this paper, a shallow-water flow solver is presented, based on the finite-volume method on unstructured grids The method is suitable for flows that occur in rivers, channels, sewer systems (1D), shallow seas, rivers, overland flow (2D), and estuaries, lakes and shelf breaks (3D). We present an outline of the numerical approach and show three 2D test cases and an application of tidal propagation on the Continental Shelf. The benefits of applying an unstructured grid were explored by creating an efficient model network that aims at keeping the number of grid cells per wavelength constant. The computational speed of our method was compared with that of WAQUA/TRIWAQ and Delft3D (the commonly used structured shallow-flow solvers in The Netherlands), and comparable performance was found.     

Faults in crystalline rock and the estimation of their mechanical properties at the Olkiluoto site,western Finland

Brittle deformation zones at the Olkiluoto nuclear repository site in western Finland play critical roles in the strength and hydrology of the host rock mass. We present a procedure implemented there for incorporating information on deformation zones obtained through boreholes into quantitative engineering design. First, ductile and brittle deformation zones are classified based on their characteristics in drillhole cores as brittle joint clusters, brittle fault zones, or semi-brittle fault zones, with an awareness of the geologic processes that caused the zones to develop as they did. Next, it is shown that the mechanical properties of the brittle deformation zones can be calculated by one of several methods, each of which has advantages and disadvantages. The site geology must be kept in mind at all stages to arrive at meaningful estimates of the mechanical properties of the deformation zones.     

A pedogenic goethite record of soil CO2 variations as a response to soil moisture content

The terrestrial carbon cycle and the role of atmospheric CO₂ concentrations in controlling global temperatures can be inferred from the study of ancient soils (paleosols). Soil-formed goethite and calcite have been the primary minerals used as a geochemical proxy for reconstructing atmospheric pCO₂ from ancient terrestrial records. In the case of goethite, optimum sampling strategies for reconstructing pCO₂ focus on the portion of the soil profile that displays steep gradients in both soil CO₂ concentration and δ¹³C values of soil CO₂ such that a keeling plot can be developed for a given soil and atmospheric pCO₂ can be calculated from it. We report data from a Carboniferous paleosol that depart from the expected linear trends. The results indicate that pedogenic goethite is sensitive to variations in the isotopic composition of soil CO₂, over a range of timescales, and can record these variations in the carbon isotope composition and mole fraction of Fe(CO₃)OH in solid solution with goethite. We explore possible environmental conditions that can drive these changes as a function of either moisture controlled variations in soil respired CO₂ or in the residence time of carbon in soils. The implications of this result are overestimation of paleoatmospheric pCO₂ from pedogenic goethite.     

Hydromechanical behavior during constant-rate pumping tests in fractured gneiss

Deformation and fluid pressure during constant-rate pumping tests were characterized by sensitivity analyses using a theoretical model of a deformable fracture, and by conducting and analyzing field tests at a site underlain by fractured biotite gneiss in western South Carolina, USA. The sensitivity analysis indicates that displacement is a hysteretic function of fluid pressure during constant-rate pumping tests, and the signals are affected by properties of the fracture (normal stiffness, aperture, and heterogeneities in the fracture plane) and enveloping rock (elastic modulus and permeability). The field tests used a removable borehole extensometer to measure axial displacements in the pumping well. The field results are generally similar to simulations, and the hydraulic and mechanical properties obtained by inversion of the pumping test results are essentially the same as results from hydromechanical slug tests. The observed displacements early in the pumping tests are less than, whereas late in the test they are greater than predicted values assuming a uniform fracture. This difference can be explained as a consequence of preferential flow within the fracture. These results indicate that displacements in a wellbore are sensitive to details of fracture connectivity and preferential flow that are difficult to detect through the pressure signal alone.     

Exploring ecological changes in Cook Inlet beluga whale habitat though traditional and local ecological knowledge of contributing factors for population decline

The Cook Inlet beluga whale, one of five Alaskan stocks, is genetically distinct and geographically isolated from other populations. Historically, Cook Inlet whales were hunted commercially, for sport, and for subsistence uses. The Marine Mammal Protection Act (MMPA) of 1972 ended commercial and sport hunting; in 1999, subsistence hunting voluntarily ended. In 2008, Cook Inlet beluga whales were listed as endangered under the Endangered Species Act after annual aerial surveys indicated the population was not recovering as expected. A combination of natural and anthropogenic factors may be affecting this population’s recovery. This study documented traditional and local ecological knowledge of Alaska Native subsistence hunters and fishers and commercial fishers through participatory research to explore ecological changes in Cook Inlet over time and to identify potential factors impacting this beluga whale population. Study results identified potential environmental and climate change factors including prey competition, health of beluga and their prey, and the presence of killer whales, the majority of which may indicate an ecosystem regime shift in the Cook Inlet region. Human-related factors included fisheries management and related prey reduction, water contamination, and anthropogenic-related noise. These results corroborate identified threats to beluga whales and also identify potential new areas of scientific investigation and management. As such this study demonstrates the value of incorporating traditional and local ecological knowledge into ongoing science and management.     

Decadal fingerprints of freshwater discharge around Greenland in a multi-model ensemble

The recent increase in the rate of the Greenland ice sheet melting has raised with urgency the question of the impact of such a melting on the climate. As former model projections, based on a coarse representation of the melting, show very different sensitivity to this melting, it seems necessary to consider a multi-model ensemble to tackle this question. Here we use five coupled climate models and one ocean-only model to evaluate the impact of 0.1 Sv (1 Sv = 10⁶ m³/s) of freshwater equally distributed around the coast of Greenland during the historical era 1965–2004. The ocean-only model helps to discriminate between oceanic and coupled responses. In this idealized framework, we find similar fingerprints in the fourth decade of hosing among the models, with a general weakening of the Atlantic Meridional Overturning Circulation (AMOC). Initially, the additional freshwater spreads along the main currents of the subpolar gyre. Part of the anomaly crosses the Atlantic eastward and enters into the Canary Current constituting a freshwater leakage tapping the subpolar gyre system. As a consequence, we show that the AMOC weakening is smaller if the leakage is larger. We argue that the magnitude of the freshwater leakage is related to the asymmetry between the subpolar-subtropical gyres in the control simulations, which may ultimately be a primary cause for the diversity of AMOC responses to the hosing in the multi-model ensemble. Another important fingerprint concerns a warming in the Nordic Seas in response to the re-emergence of Atlantic subsurface waters capped by the freshwater in the subpolar gyre. This subsurface heat anomaly reaches the Arctic where it emerges and induces a positive upper ocean salinity anomaly by introducing more Atlantic waters. We found similar climatic impacts in all the coupled ocean–atmosphere models with an atmospheric cooling of the North Atlantic except in the region around the Nordic Seas and a slight warming south of the equator in the Atlantic. This meridional gradient of temperature is associated with a southward shift of the tropical rains. The free surface models also show similar sea-level fingerprints notably with a comma-shape of high sea-level rise following the Canary Current.