Infrared investigation of CO2-bearing cordierites

CO₂ molecules were introduced experimentally into the structural channels of synthetic well ordered Mgcordierite (Mg₂ ^[VI][(Al₄Si₅)^[IV]O₁₈]) at temperatures of 600 and 800° C, and pressures of 7, 8, 10, 12, and 25 kbar. Powder infrared spectra of the run products show five absorption bands in the region of the asymmetric stretching mode of CO₂. Two of them, strong and sharp, occurring at 2353 cm^–1 {2} and 2348 cm^–1 {3}, are related to two different types of CO₂ molecules. The relative intensity of the band {2} (type I) increases with the cell parameter c_o whereas the relative intensity of the band {3} (type II) increases with the parameter a₀ of the crystal. It is concluded that CO₂ molecules of type I may be oriented with their elongation parallel to the c-axis of the crystal, while CO₂ molecules of type II lie with their O-C-O vector parallel to the a-axis. Analytical data indicate that the intensity ratio Z of these two bands ({2}/{3}) is a linear function of the CO₂ content of cordierite. This ratio depends also on the temperature and, to a less extent, on the pressure under which cordierite entrapped CO₂ molecules. It is proposed to combine this infrared parameter Z together with an estimate of the P-T conditions of the incorporation of CO₂ into the channels, in order to determine the CO₂ content of natural cordierites. The samples do not need to be of high purity and only small amounts (<5 mg) are necessary. This semi-empirical analytical method, which does not require complicated data treatments, is suitable for CO₂-rich cordierites of granulite facies rocks.     

Altered landscapes, altered livelihoods: The shifting experience of informal waste collecting during Hanoi’s urban transition

A growing body of literature is concerned with urbanization processes in contemporary Vietnam and how the country’s globalizing cities of Hanoi and Ho Chi Minh City are increasingly becoming spaces of consumption. However, much less is known about how these changing spaces accommodate labour, and in turn support livelihoods. Using published empirical data on Hanoi’s informal waste collectors from 1992 [DiGregorio, M., 1994. Urban Harvest: Recycling as a Peasant Industry in Northern Vietnam. East–West Center, Hawaii, pp. 1–212] and my own data, including a survey of 575 waste collectors and 44 interviews, collected on Hanoi’s informal waste collectors in 2006, I explore the experiences of informal waste collectors (waste pickers and itinerant junk buyers) in Vietnam’s capital city of Hanoi. I argue that Vietnam’s globalizing economy and urban transition have been a catalyst for the growth of the informal waste collector population in Hanoi as well as a partial player in the gendering of this group and the work they undertake.     

National contributions to climate change mitigation from agriculture: allocating a global target

Globally, agriculture and related land use change contributed about 17% of the world’s anthropogenic GHG emissions in 2010 (8.4 GtCO₂e yr^?1), making GHG mitigation in the agriculture sector critical to meeting the Paris Agreement’s 2°C goal. This article proposes a range of country-level targets for mitigation of agricultural emissions by allocating a global target according to five approaches to effort-sharing for climate change mitigation: responsibility, capability, equality, responsibility-capability-need and equal cumulative per capita emissions. Allocating mitigation targets according to responsibility for total historical emissions or capability to mitigate assigned large targets for agricultural emission reductions to North America, Europe and China. Targets based on responsibility for historical agricultural emissions resulted in a relatively even distribution of targets among countries and regions. Meanwhile, targets based on equal future agricultural emissions per capita or equal per capita cumulative emissions assigned very large mitigation targets to countries with large agricultural economies, while allowing some densely populated countries to increase agricultural emissions. There is no single ‘correct’ framework for allocating a global mitigation goal. Instead, using these approaches as a set provides a transparent, scientific basis for countries to inform and help assess the significance of their commitments to reducing emissions from the agriculture sector.

Key policy insights

• Meeting the Paris Agreement 2°C goal will require global mitigation of agricultural non-CO₂ emissions of approximately 1 GtCO₂e yr^?1 by 2030.

• Allocating this 1 GtCO₂e yr^?1 according to various effort-sharing approaches, it is found that countries will need to mitigate agricultural business-as-usual emissions in 2030 by a median of 10%. Targets vary widely with criteria used for allocation.

• The targets calculated here are in line with the ambition of the few countries (primarily in Africa) that included mitigation targets for the agriculture sector in their (Intended) Nationally Determined Contributions.

• For agriculture to contribute to meeting the 2°C or 1.5°C targets, countries will need to be ambitious in pursuing emission reductions. Technology development and transfer will be particularly important.

     

Intercomparison of snow water equivalent observations in the Northern Great Plains

In the Northern Great Plains, melting snow is a primary driver of spring flooding, but limited knowledge of the magnitude and spatial distribution of snow water equivalent (SWE) hampers flood forecasting. Passive microwave remote sensing has the potential to enhance operational river flow forecasting but is not routinely incorporated in operational flood forecasting. We compare satellite passive microwave estimates from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR‐E) to the National Oceanic and Atmospheric Administration Office of Water Prediction (OWP) airborne gamma radiation snow survey and U.S. Army Corps of Engineers (USACE) ground snow survey SWE estimates in the Northern Great Plains from 2002 to 2011. AMSR‐E SWE estimates compare favourably with USACE SWE measurements in the low relief, low vegetation study area (mean difference = ?3.8 mm, root mean squared difference [RMSD] = 34.7 mm), but less so with OWP airborne gamma SWE estimates (mean difference = ?9.5 mm, RMSD = 42.7 mm). An error simulation suggests that up to half of the error in the former comparison is potentially due to subpixel scale SWE variability, limiting the maximum achievable RMSD between ground and satellite SWE to approximately 26–33 mm in the Northern Great Plains. The OWP gamma versus AMSR‐E SWE comparison yields larger error than the point‐scale USACE versus AMSR‐E comparison, despite a larger measurement footprint (5–7 km² vs. a few square centimetres, respectively), suggesting that there are unshared errors between the USACE and OWP gamma SWE data.     

Beyond the “fit”: introducing climate forecasts among organic farmers in Georgia (United States)

Organic farmers are a prime clientele for climate services by virtue of their social profile and vulnerability of produce to climate extremes. The study draws on an online survey and in-depth interviews with organic farmers in Georgia (United States). It shows that organic farmers access and act on climate information in ways that reflect their emphasis on diversified and flexible systems. They favor a pluralistic knowledge base that integrates scientific expertise with place-based experience and intuitive understandings. Their management style combines information at multiple temporal scales and draws on a range of technical and social resources. Translating climate forecasts into usable science for organic farming requires attention to the identities, commitments, and relationships that define the organic farming community.     

Evaluation of sewage source and fate on southeast Florida coastal reefs

Water, sponge and coral samples were collected from stations impacted by a variety of pollution sources and screened for human enteric viruses as conservative markers for human sewage. While human enteroviruses and adenoviruses were not detected, noroviruses (NoV; human genogroups I and II) were detected in 31% of samples (especially in sponge tissue). Stations near inlets were the only ones to show multiple sample types positive for NoV. Fecal indicator bacteria and enteric viruses were further evaluated at multiple inlet stations on an outgoing tide. Greatest indicator concentrations and highest prevalence of viruses were found at the mouth of the inlet and offshore in the inlet plume. Results suggest that inlets moving large volumes of water into the coastal zone with tides may be an important source of fecal contaminants. Efforts to reduce run-off or unintended release of water into the Intracoastal Waterway may lower contaminants entering sensitive coastal areas.     

Geologic and infrastructure factors for delineating areas for clean coal: examples in Texas, USA

Texas has a wide variety of areas that can be targeted for new clean-coal facilities. These areas are delineated by mapping spatial linkages between coal- and lignite-bearing formations, groundwater and surface-water resources, and CO₂ sinks in brine formations for long-term CO₂ storage or in mature oil fields with potential for enhanced oil recovery (EOR). However, a variety of infrastructure factors make it feasible to also target numerous areas outside coal and lignite basins in Texas. These infrastructure factors include pipelines for delivery of CO₂ to subsurface sinks and delivery of coal-produced hydrogen to refineries, ease of connection to existing transmission lines, distribution of nonattainment areas where new clean-coal facilities could be constructed and be compliant with strict air-quality standards, and railroads that can transport coal and other feedstock to new clean-coal facilities. Primary regions in Texas where favorably co-located CO₂ source-sink factors related to coal and lignite trends include the Gulf Coast, the Eastern Shelf of the Permian Basin, and the Fort Worth Basin. However, areas outside coal and lignite basins, particularly the Permian Basin where a new clean-coal facility is being planned, also have clean-coal potential because of existing CO₂ pipelines and proximity to EOR fields that can economically sustain new clean-coal facilities.     

Integrating science into management: Ecological carrying capacity of bivalve shellfish aquaculture

Ecosystem-based management (EBM), despite the best efforts of managers, researchers, and policy makers, often falls short of its intended purpose resulting in inadequate protection of resources. Coastal habitats are particularly vulnerable to poor management due to high use and potential for user conflict. EBM can be improved when it is informed by ecological science and considers the socio-economic needs of the community. Communication between scientists and stakeholders can help to prevent adverse outcomes while enhancing protection and sustainability of the coastal environment. In the research presented here, a framework is used to guide and enhance communication between scientists and stakeholders for sustainable management of resources and equity of all users. The outcome of this applied framework is a long-term plan to guide the management of an oyster aquaculture industry using carrying capacity as an estimate for the basis of management decisions. Central to the framework is the Working Group on Aquaculture Regulations (WGAR), which represents a diverse group of stakeholders. The WGAR worked closely with ecological modelers over a two-year period using mass-balance modeling to calculate ecological carrying capacity for oyster aquaculture in two ecosystems: Narragansett Bay and a set of highly flushed temperate lagoons in Rhode Island, USA. Collaboration between scientists and the WGAR greatly improved the models and stakeholder understanding of the science and acceptance of the results. Aquaculture is increasing in coastal regions world-wide and this framework should be easily transferable to other areas suffering from similar user conflict issues.     

AVIATR—Aerial Vehicle for In-situ and Airborne Titan Reconnaissance

We describe a mission concept for a stand-alone Titan airplane mission: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR). With independent delivery and direct-to-Earth communications, AVIATR could contribute to Titan science either alone or as part of a sustained Titan Exploration Program. As a focused mission, AVIATR as we have envisioned it would concentrate on the science that an airplane can do best: exploration of Titan??s global diversity. We focus on surface geology/hydrology and lower-atmospheric structure and dynamics. With a carefully chosen set of seven instruments??2 near-IR cameras, 1 near-IR spectrometer, a RADAR altimeter, an atmospheric structure suite, a haze sensor, and a raindrop detector??AVIATR could accomplish a significant subset of the scientific objectives of the aerial element of flagship studies. The AVIATR spacecraft stack is composed of a Space Vehicle (SV) for cruise, an Entry Vehicle (EV) for entry and descent, and the Air Vehicle (AV) to fly in Titan??s atmosphere. Using an Earth-Jupiter gravity assist trajectory delivers the spacecraft to Titan in 7.5 years, after which the AVIATR AV would operate for a 1-Earth-year nominal mission. We propose a novel ??gravity battery?? climb-then-glide strategy to store energy for optimal use during telecommunications sessions. We would optimize our science by using the flexibility of the airplane platform, generating context data and stereo pairs by flying and banking the AV instead of using gimbaled cameras. AVIATR would climb up to 14?km altitude and descend down to 3.5?km altitude once per Earth day, allowing for repeated atmospheric structure and wind measurements all over the globe. An initial Team-X run at JPL priced the AVIATR mission at FY10 $715M based on the rules stipulated in the recent Discovery announcement of opportunity. Hence we find that a standalone Titan airplane mission can achieve important science building on Cassini??s discoveries and can likely do so within a New Frontiers budget.     

Analysis of tidal marsh vegetation patterns in two Georgia estuaries using aerial photography and GIS

Aerial photographs and GIS analysis were used to map the distribution of tidal marsh vegetation along the salinity gradients of the estuaries of the Altamaha and Satilla Rivers in coastal Georgia. Vegetation maps were constructed from 1993 U.S. Geological Survey Digital Orthophoto Quarter Quads, 1∶77,000-scale color infrared photographs taken in 1974 and 1∶24,000-scale black and white photographs taken in 1953, Changes between years were identified using a GIS overlay analysis. Four vegetation classifications were identified and groundtruthed with field surveys: salt marsh (areas containing primarilySpartina alterniflora), brackish marsh (Spartina cynosuroides andS. alterniflora), Juncus (Juncus roemerianus), and fresh marsh (Zizania aquatica, Zizaniopsis miliacae, and others). There was no evidence for an upstream shift in marsh vegetation along the longitudinal axis of either estuary over the time frame of this analysis, which implies there has not been a long-term increase in salinity. Although the inland extent of each marsh zone was further upstream in the Satilla than the Altamaha, they corresponded to similar average high tide salinities in each estuary: areas classified as salt marsh occurred from the mouth up to where average high tide salinity in the water was approximately 15 psu;Juncus ranged from 21 to 1 psu; brackish marsh ranged from 15 to 1 psu; and fresh marsh was upstream of 1 psu. Approximately 63% of the 6,786 ha of tidal marsh vegetation mapped in the Altamaha and 75% of the 10,220 ha mapped in the Satilla remained the same in all 3 yr.Juncus was the dominant classification in the intermediate regions of both estuaries, and shifts between areas classified asJuncus and either brackish or salt marsh constituted the primary vegetation change between 1953 and 1993 (87% of the changes observed in the Altamaha and 95% of those in the Satilla). This analysis suggests that the broad distribution of tidal marsh vegetation along these two estuaries is driven by salinity, but that at the local scale these are dynamic systems with a larger number of factors affecting the frequently changing borders of vegetation patches.