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111.
United Nations climate change conferences have attracted an increasing number and range of observer participants, often outnumbering national delegates. The interactions between the formal and informal spaces of climate governance at the Conference of the Parties (COP) are explored by investigating why non-nation state actors (NNSAs) attend them and by measuring to what extent official UN Side Events provide relevant information for the formal negotiations. Based on primary empirical research at recent COPs, it is found that 60–75% of Side Events have related directly to items under negotiation in the post-2012 climate negotiations. In this regard, Side Events that facilitate informal exchange between stakeholders not only provide input into the negotiations but also allow issues beyond the realm of the negotiations to be discussed, reflecting the scope of climate change. Although Side Events are an effective forum to exchange ideas and network, their current format and purpose as being events ‘on the side’ does not offer a sufficient framework for coordination between the work of NNSAs and the United Nations Framework Convention on Climate Change (UNFCCC) process. 相似文献
112.
Niels BORMANN David DUNCAN Stephen ENGLISH Sean HEALY Katrin LONITZ Keyi CHEN Heather LAWRENCE Qifeng LU 《大气科学进展》2021,38(8):1285-1298
This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4. 相似文献
113.
114.
Colette C.A. Starheim Christopher Gomez Justin Harrison Claire Kain Nicholas J. Brewer Kirsty Owen Danang Sri Hadmoko Heather Purdie Peyman Zawar‐Reza Ian Owens Patrick Wassmer Franck Lavigne 《New Zealand geographer》2013,69(1):26-38
Previous research on debris‐flow deposit structure typically reports little to no visually discernible stratigraphy. The preliminary findings presented here provide evidence for more complex internal deposit architecture with inverse grading and subunits thought to reflect individual flow surges. Ground‐penetrating radar surveys, geospatial data and field observations are used to describe 10 subunits traceable over the 14 lateral radargrams imaging the lower 38 m of the deposit. Additional subunits are depicted further upslope in a longitudinal transect. As well as demonstrating the need for continued investigation of deposit architecture using non‐traditional techniques, these results may help improve future interpretations of post‐event deposits. 相似文献
115.
Brian G. Katz James A. Kingsbury Heather L. Welch Roland W. Tollett 《Environmental Earth Sciences》2012,65(6):1759-1780
Groundwater chemistry and tracer-based age data were used to assess contaminant movement and geochemical processes in the
middle Claiborne aquifer (MCA) of the Mississippi embayment aquifer system. Water samples were collected from 30 drinking-water
wells (mostly domestic and public supply) and analyzed for nutrients, major ions, pesticides, volatile organic compounds (VOCs),
and transient age tracers (chlorofluorocarbons, tritium and helium-3, and sulfur hexafluoride). Redox conditions are highly
variable throughout the MCA. However, mostly oxic groundwater with low dissolved solids is more vulnerable to nitrate contamination
in the outcrop areas east of the Mississippi River in Mississippi and west Tennessee than in mostly anoxic groundwater in
downgradient areas in western parts of the study area. Groundwater in the outcrop area was relatively young (apparent age
of less than 40 years) with significantly (p < 0.05) higher dissolved oxygen and nitrate–N concentrations and higher detections of pesticides and VOCs compared to water
samples from wells in downgradient areas. Oxygen reduction and denitrification rates were low compared to other aquifers in
the United States (zero order rate constants for oxygen reduction and denitrification were 4.7 and 5–10 μmol/L/year, respectively).
Elevated concentrations of nitrate–N, and detections of pesticides and VOCs in some deep public supply wells (>50 m depth)
indicated contaminant movement from shallow parts of the aquifer into deeper oxic zones. Given the persistence of nitrate
in young oxic groundwater that was recharged several decades ago, and the lack of a confining unit, the downward movement
of young contaminated water may result in higher nitrate concentrations over time in deeper parts of the aquifer containing
older oxic water. 相似文献
116.
Long-term retreat rates of Puget Sound's unconsolidated sediment shorelines have been difficult to quantify, and little systematic research has been completed to constrain retreat in this area. We put forward a new application of cosmogenic 10Be exposure dating to assess long-term shoreline retreat on Whidbey Island, WA by dating lag boulders exposed on the shore platform as the shoreline erodes. Production of 10Be in shoreline boulders is modulated by both tidal submergence and topographic shielding from the retreating bluff. By modeling the combined effect of these variables on 10Be production, the timing of exposure can be determined and used to calculate long-term (103–104 yr) bluff retreat rates. In rare cases, retreat rates are underestimated due to inherited 10Be. Within the study area, average retreat rates ranged between 0 and 8 cm yr? 1. Our results demonstrate the utility of cosmogenic nuclides for determining long-term shoreline retreat rates in areas with thick sediment cover, where large numbers of samples can be collected, and where the pre-depositional history of the boulders is uncomplicated. 相似文献
117.
Jacob B. Lowenstern Heather Bleick Jorge A. Vazquez Jonathan M. Castro Peter B. Larson 《Bulletin of Volcanology》2012,74(10):2303-2319
We investigated the distribution of Cl, F, Li, and Be in pumices, obsidians, and crystallized dome rocks at Chaitén volcano in 2008?C2009 in order to explore the behavior of these elements during explosive and effusive volcanic activity. Electron and ion microprobe analyses of matrix and inclusion glasses from pumice, obsidian, and microlite-rich dome rock indicate that Cl and other elements were lost primarily during crystallization of the rhyolitic dome after it had approached the surface. Glass in pumice and microlite-free obsidian has 888?±?121?ppm Cl, whereas residual glass in evolved microlite-rich dome rock generally retains less Cl (as low as <100?ppm). Estimated Cl losses were likely >0.7?Mt Cl, with a potential maximum of 1.8?Mt for the entire 0.8-km3 dome. Elemental variations reflect an integrated bulk distribution ratio for Cl?>?1.7 (1.7 times more Cl was degassed or incorporated into crystals than remained in the melt). Because Cl is lost dominantly as the very last H2O is degassed, and Cl is minimally (if at all) partitioned into microlites, the integrated vapor/melt distribution ratio for Cl exceeds 200 (200 times more Cl in the evolved vapor than in the melt). Cl is likely lost as HCl, which is readily partitioned into magmatic vapor at low pressure. Cl loss is accelerated by the change in the composition of the residual melt due to microlite growth. Cl loss also may be affected by open-system gas fluxing. Integrated vapor-melt distribution ratios for Li, F, and Be all exceed 1,000. On degassing, an unknown fraction of these volatiles could be immediately dissolved in rainwater. 相似文献
118.
Heather L. Purdie Martin S. Brook Ian C. Fuller John Appleby 《New Zealand geographer》2008,64(1):5-19
Abstract: Seasonal variations in ablation and surface velocity were investigated on the lower Fox Glacier. Variations occur between summer and winter ablation, with surface velocity also showing marked seasonality. Recent advance has resulted in the glacier gaining around 200 m length since late 2004. Longer term, Fox Glacier appears linked to the Southern Oscillation Index, with positive glacier mass balances associated with negative Southern Oscillation Index (El Niño). An estimated glacier response time of approximately 9–14 years suggests the current terminus advance was linked to mass gains in the mid-1990s. Recent collapses at the terminal face continue to prove a hazard at this busy tourist destination. 相似文献
119.
120.
Heather Schijns Suvi Heinonen Douglas R. Schmitt Pekka Heikkinen Ilmo T. Kukkonen 《Geophysical Prospecting》2009,57(6):997-1008
A traveltime inversion technique is applied to model the upper ∼40 m of the subsurface of a glaciated shield rock area in order to calculate static corrections for a multi-azimuth multi-depth walk-away vertical seismic profile and a surface seismic reflection profile. First break information from a seismic refraction survey is used in conjunction with a ray-tracing program and an iterative damped least-squares inversion algorithm to create a two-dimensional model of the subsurface. The layout of the seismic survey required crooked seismic lines and substantial gaps in the source and receiver coverage to be accounted for. Additionally, there is substantial topographical variation and a complex geology consisting of glaciofluvial sediment and glacial till overlying a crystalline bedrock. The resolution and reliability of the models is measured through a parameter perturbation technique, normalized χ2 values, root means square traveltime residuals and comparison to known geology. 相似文献