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181.
Stockmann KD Anderson NM Skog KE Healey SP Loeffler DR Jones G Morrison JF 《Carbon balance and management》2012,7(1):1
Background
Global forests capture and store significant amounts of CO2 through photosynthesis. When carbon is removed from forests through harvest, a portion of the harvested carbon is stored in wood products, often for many decades. The United States Forest Service (USFS) and other agencies are interested in accurately accounting for carbon flux associated with harvested wood products (HWP) to meet greenhouse gas monitoring commitments and climate change adaptation and mitigation objectives. This paper uses the Intergovernmental Panel on Climate Change (IPCC) production accounting approach and the California Forest Project Protocol (CFPP) to estimate HWP carbon storage from 1906 to 2010 for the USFS Northern Region, which includes forests in northern Idaho, Montana, South Dakota, and eastern Washington. 相似文献182.
183.
Vegetative remains of three coalified Lower Devonian vascular plants (Zosterophyllum, Psilophyton, Renalia) were analyzed using flash pyrolysis-gas chromatography-mass spectrometry. The distributions of pyrolysis products are compared with those from younger vascular plant fossil xylem (Cordaixylon, Callixylon) and cuticle (Pachypteris). The likelihood of the chemical preservation of characteristic higher plant macromolecules (e.g., lignin and cutan) in the Lower Devonian plant fossils is considered in light of this comparison and associated thermal maturity assessments. Reflectance values from vitrinite-like macerals, which may not be vitrinite sensu stricto in the Lower Devonian host rocks for the fossils selected for this study, are shown to provide a reasonable assessment of the thermal maturity of these early vascular plant fossils. Although lignin altered through burial maturation is the most likely source of the prominent alkylphenols and aromatic hydrocarbons in the Lower Devonian tracheophyte flash pyrolysates, a contribution from thermally modified tannins cannot be ruled out. Comparison of the highly aliphatic pyrolysates from the Zosterophyllum and Psilophyton axes with that of a thermally mature fossil gymnosperm leaf revealed that cutan was an important component in the Devonian plant remains. This is the earliest chemical evidence for the presence of cutan in vascular plants. 相似文献
184.
Numerical simulations show that inclusion of meso-scale bathymetry can enhance poleward eastern boundary undercurrents. 相似文献
185.
In part of a large abandoned mining complex, electromagnetic geophysical surveys were used along with data derived from cores and monitoring wells to infer sources of contamination and subsurface hydrologic connections between acidic refuse deposits and adjacent undisturbed geologic materials.Electrical resistivity increases sharply along the boundary of an elevated deposit of pyritic coarse refuse, which is highly contaminated and electrically conductive, indicating poor subsurface hydrologic connections with surrounding deposits of fine refuse and undisturbed glacial material. Groundwater chemistry, as reflected in values of specific conductance, also differs markedly across the deposit's boundary, indicating that a widespread contaminant plume has not developed around the coarse refuse in more than 40 yr since the deposit was created. Most acidic drainage from the coarse refuse is by surface runoff and is concentrated around stream channels.Although most of the contaminated groundwater within the study area is concentrated within the surficial refuse deposits, transects of apparent resistivity and phase angle indicate the existence of an anomalous conductive layer at depth (>4 m) in thick alluvial sediments along the northern boundary of the mining complex. Based on knowledge of local geology, the anomaly is interpreted to represent a subsurface connection between the alluvium and a flooded abandoned underground mine. 相似文献
186.
Regional landslide risk to the Cairns community 总被引:10,自引:0,他引:10
A GIS-based regional reconnaissance-level assessment of landslide risk to the Cairns community has been carried out to provide information to the Cairns City Council for planning and emergency management purposes. Magnitude recurrence relations were tentatively established for the two main slope processes: landslides on the hill slopes; and large debris flows extending out from the gully systems on to the plains. From the recurrence relations, landslide hazard (H) was estimated as the annual probability of a point being impacted by a landslide. The nature, number (E) and geographic distribution of the elements at risk were obtained by interrogating the GIS, and their vulnerabilities (V) to destruction by the two main landslide slope processes were assessed. From this information, specific risk (= H × V) and total risk (= H × V× E) maps were produced.Although total landslide risk is relatively low at present, it will increase as development extends further into the hill slopes, unless adequate mitigation measures are taken. Large debris flows, while considerably less frequent than landslides on cut slopes, could impact on subdivisions at the base of the slopes. Blockage by landslides of roads and railways providing access to Cairns can cause isolation of the community. Flash flooding in Freshwater Creek, or debris flows, have the potential to disrupt the Cairns water supply by blocking the intake or destroying sections of the pipeline. 相似文献
187.
Hurricane 07B in the Godavari Delta, Andhra Pradesh, India: vulnerability, mitigation and the spatial impact 总被引:1,自引:0,他引:1
Greg O'Hare 《The Geographical journal》2001,167(1):23-38
Few hurricane impact studies provide robust spatial parameters of damage or relate geographical patterns of destruction accurately to storm trajectories or agencies. A detailed spatial analysis is, therefore, presented of the destruction caused by tropical hurricane 07B which made landfall on 6/7 November 1996 over the Godavari Delta region, Andhra Pradesh, eastern India. Patterns of destruction by storm surge, wind and flood water are quantitatively mapped for death tolls, house destruction and agricultural damage using local administrative ( mandal ) data bases. Results show that most impact occurred near the coast, but a well-defined path of destruction across the central part of the delta can be identified. Such mapping studies fail to indicate the types of individuals and social groups most affected by the storm hazard and their response to it. An investigation of landowning farmers, female migrant rural labourers and fishing communities in the delta shows that poverty and social ordering in Indian society puts differential limits on the risk reduction abilities of individuals and social groups in the face of the cyclone hazard. The paper also demonstrates that 'top down' institutional measures to reduce the effects of storm damage such as those introduced in the aftermath of hurricane 07B, including early storm warning and evacuation procedures and rehabilitation programmes, remain largely ineffective. It is suggested that the introduction of more 'bottom up' community-based programmes which seek to improve the risk awareness and risk avoiding abilities of affected individuals and groups would be much more beneficial. The case material on hurricane 07B and its effects are placed in context by reviewing and updating long and medium-term time series records of storm frequencies and impacts in the Bay of Bengal and particularly along the eastern coastline of India. 相似文献
188.
189.
A reclamation project at the abandoned Blackhawk Mine site near Terre Haute, Indiana, lasted about four months and involved the burial of coarse mine refuse in shallow (less than 9 m) pits excavated into loess and till in an area of about 16 ha. An abandoned flooded underground coal mine underlies the reclamation site at a depth of about 38 m; the total area underlain by the mine is about 10 km2. The potentiometric levels associated with the mine indicate a significant (2.7 m) and prolonged perturbation of the deeper confined groundwater system; 14 months after completing reclamation, the levels began to rise linearly (at an average rate of 0.85 cm/d) for 11 months, then fell exponentially for 25 months, and are now nearly stable. Prominent subsidence features exist near the reclamation site. Subsidence-related fractures were observed in cores from the site, and such fractures may have provided a connection between the shallower and deeper groundwater systems. 相似文献
190.
The relationship between tropical cyclone activity and ENSO is examined for the major cyclone regions using crosscorrelations,spectral analysis and composite analysis of eastern equatorial Pacific sea surface temperature,thenormalised monthly Southern Oscillation Index(SOI),and tropical cyclone frequencies.The closest relationship betweenthe 3—4 year ENSO period and tropical cyclone activity was found in the western North Pacific west of 160°E and thereseems to be significant potential for seasonal forecasting in this region based on ENSO parameters alone.No significantrelationships were found for the North Indian Ocean,and the remainder of the basins were dominated by oscillationsnear the quasi-biennial period.Physical explanations and forecasting of the seasonal variations in tropical cyclone num-bers in these regions will need to account for the QBO as well as the 3—4 year ENSO connections. 相似文献