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1.
Abstract

The First Nations (Da ‘naxda ‘xw) village of Kwalate, Knight Inlet, British Columbia was located along the shore of a funnel‐shaped bay. Archaeological investigations show that this was a major village that stretched 90 m along the shoreline and was home to possibly 100 or more inhabitants. Oral stories indicate that the village was completely swept away by a tsunami that formed when an 840‐m high rock avalanche descended into the water on the opposite side of the fjord. Shipboard geological mapping, combined with empirical tsunami modelling, indicate that the tsunami was likely 2 to 6 m high prior to run‐up into the village. Radiocarbon dates reveal that the village was occupied from the late 1300s CE until the late 1500s CE when it was destroyed by the tsunami.  相似文献   

2.
Abstract

A two‐dimensional, hydrostatic numerical model of the tides in Knight Inlet is compared with observations of velocity and density obtained from three cyclesonde moorings. The observations from a fourth cyclesonde mooring were used to provide boundary data at the open end of the model. The time period in the fjord that the model simulates was a period of high, freshwater runoff, so that the fjord had a distinct, surface layer. The use of high, vertical resolution was avoided by attaching a homogeneous, fresh, surface layer to the top of the model. The density equation was linearized about a mean, fixed density field, and the mixing of density was not allowed.

The model reproduces the semidiurnal (M2, S2 and N2) and diurnal (K1 and O1) velocity and density signals in the inlet. The shallow‐water constituents (M4 and MK3) are reproduced even though the density equation has been linearized. The fortnightly constituent (MSf) is poorly simulated. When the advection terms in the momentum equation are set to zero, the basic features of the semidiurnal and diurnal constituents are still reproduced, but the shallow‐water constituents are poorly simulated.

The energy flux along the inlet of the M2 internal tide is insensitive to the advective terms in the momentum equation. The total rate of dissipation of M2 energy is similar to the energy flux in the M2 internal tide near the sill, which implies that, according to the model, most of the energy removed from the barotropic tide is fed into the internal tide. The majority of the energy in the M2 internal tide is dissipated close to the sill of the inlet, but enough of the energy makes its way to the head of the inlet to reflect and set up a recognizable standing wave pattern.  相似文献   

3.
Abstract

Observations of the tidal jet issuing from Quatsino Narrows into Rupert‐Holberg Inlet, B.C. are discussed. Two types of flow are observed: a buoyant surface jet and a negatively buoyant jet. The buoyant flow is parameterized with an initial densimetric Froude number, and agreement is good between the observed vertical penetration of the jet and that predicted by several existing models. The negatively buoyant jet entrains several times its initial volume; entrainment constants for the flow are larger than those observed from the two‐dimensional plume on similar inclines, yet smaller than those for neutrally buoyant jets. A time‐scale of 2 to 3 weeks is calculated for the flushing of the Inlet during times of negatively buoyant inflow. The buoyant jet is observed to reduce the overall density of the water column, and estimated vertical eddy diffusivities are considerably larger than in most other fjords. Changes in the Froude number of the jet are controlled primarily by changes in the density and speed of the inflow. During the period of observations the density of the jet appears to be controlled by runoff.  相似文献   

4.
Abstract

A simple perturbation procedure is developed for incorporating the effects of mean zonal winds in atmospheric tidal calculations. This method is used to determine the variation of the solar semidiurnal surface pressure oscillation, S2(p), that is expected to result from the mean wind changes during the course of the quasi‐biennial oscillation of the tropical stratosphere. The results are consistent with earlier observations of a quasi‐biennial variation in S2(p). Some new observations of biennial variability in S2(p) at four tropical stations are also discussed.  相似文献   

5.
Abstract

This work presents the climatology of the sulphur dioxide column over Thessaloniki derived from three years of observation with the Brewer spectrophotometer. The SO2 column averages 2.5 m atm‐cm and the shielding of UV‐B by SO2 is investigated and compared with the changes in shielding resulting from an anticipated ozone reduction. Columnar and surface SO2 concentrations over Thessaloniki appear to be typical of those in major industrial‐urban regions of the world. It is concluded that, for urban regions, predictions of changes in UV‐B as a result of man's activities must consider projections of changes in the SO2 column as well as ozone.  相似文献   

6.
Abstract

The dependence of ozone formation on the mixing ratios of volatile organic compounds (VOCs) and nitrogen oxides (NOx) has been widely studied. In addition to the atmospheric levels of VOCs and NOx, the extent of photochemical processing of VOCs has a strong impact on ozone levels. Although methods for measuring atmospheric mixing ratios of VOCs and NOx are well established and results of those measurements are widely available, determination of the extent of photochemical processing of VOCs, known as photochemical age (PCA), is difficult. In this article a recently developed methodology for the determination of PCA for individual compounds based on the change in their stable carbon isotope composition is used to investigate the dependence between ozone and VOC or NOx mixing ratios at a rural site in Ontario, Canada, during fall and winter. The results show that under these conditions the variability in VOC mixing ratios is predominantly a result of the varying impact of local emissions and not a result of changes in the extent of atmospheric processing. This explains why the mixing ratio of ozone shows no systematic dependence on the mixing ratios of VOCs or NOx in this environment and at this time of the year.  相似文献   

7.
As the number of instruments applied in the area of energy and climate policy is rising, the issue of policy interaction needs to be explored further. This article analyses the interdependencies between the EU Emissions Trading Scheme (EU ETS) and the German feed-in tariffs (FITs) for renewable electricity in a quantitative manner using a bottom-up energy system model. Flexible modelling approaches are presented for both instruments, with which all impacts on the energy system can be evaluated endogenously. It is shown that national climate policy measures can have an effect on the supranational emissions trading system by increasing emission reduction in the German electricity sector by up to 79 MtCO2 in 2030. As a result, emission certificate prices decline by between 1.9 €/tCO2 and 6.1 €/tCO2 and the burden sharing between participating countries changes, but no additional emission reduction is achieved at the European level. This also implies, however, that the cost efficiency of such a cap-and-trade system is distorted, with additional costs of the FIT system of up to €320 billion compared with lower costs for ETS emission certificates of between €44 billion and €57 billion (cumulated over the period 2013–2020).

Policy relevance

In order to fulfil ambitious emission reduction targets a large variety of climate policy instruments are being implemented in Europe. While some, like the EU ETS, directly address CO2 emissions, others aim to promote specific low-carbon technologies. The quantitative analysis of the interactions between the EU ETS and the German FIT scheme for renewable sources in electricity generation presented in this article helps to understand the importance of such interaction effects. Even though justifications can be found for the implementation of both types of instrument, the impact of the widespread use of support mechanisms for renewable electricity in Europe needs to be taken into account when fixing the reduction targets for the EU ETS in order to ensure a credible long-term investment signal.  相似文献   

8.
Abstract

Satellite observations revealed that there is a close relationship between perturbations of sea surface temperature (SST) and wind stress (τ) induced by tropical instability waves (TIWs; SSTTIW and τ TIW). Using the empirical relationship observed between TIW-induced wind stress divergence (curl) and downwind (crosswind) SST gradients, this study establishes a TIW-induced wind stress field perturbation model τ TIW?=?F(SST). This empirical model solves τ TIW from the TIW-induced wind stress divergence and curl, which are estimated from the downwind and crosswind SST gradients. This empirical τ TIW?=?F(SST) model can be incorporated into the ocean model to take into account the effect of τ TIW. By comparing two experiments with and without the τ TIW effect, this study demonstrates that τ TIW has a substantial effect on the equatorial Pacific heat budget and induces the long-term mean SST to exhibit a 0.2°C difference, which is consistent with previous studies.  相似文献   

9.
Tropospheric distributions of ozone (O3) and water vapor (H2O) have been presented based on the Measurements of OZone and water vapor by Airbus In-Service AirCraft (MOZAIC) data over the metro and capital city of Delhi, India during 1996–2001. The vertical mixing ratios of both O3 and H2O show strong seasonal variations. The mixing ratios of O3 were often below 40 ppbv near the surface and higher values were observed in the free troposphere during the seasons of winter and spring. In the free troposphere, the high mixing ratio of O3 during the seasons of winter and spring are mainly due to the long-range transport of O3 and its precursors associated with the westerly-northwesterly circulation. In the lower and middle troposphere, the low mixing ratios of ∼20–30 ppbv observed during the months of July–September are mainly due to prevailing summer monsoon circulation over Indian subcontinent. The summer monsoon circulation, southwest (SW) wind flow, transports the O3-poor marine air from the Arabian Sea and Indian Ocean. The monthly averages of rainfall and mixing ratio of H2O show opposite seasonal cycles to that of O3 mixing ratio in the lower and middle troposphere. The change in the transport pattern also causes substantial seasonal variation in the mixing ratio of H2O of 3–27 g/kg in the lower troposphere over Delhi. Except for some small-scale anomalies, the similar annual patterns in the mixing ratios of O3 and H2O are repeated during the different years of 1996–2001. The case studies based on the profiles of O3, relative humidity (RH) and temperature show distinct features of vertical distribution over Delhi. The impacts of long range transport of air mass from Africa, the Middle East, Indian Ocean and intrusions of stratospheric O3 have also been demonstrated using the back trajectory model and remote sensing data for biomass burning and forest fire activities.  相似文献   

10.
A high resolution global model of the terrestrial biosphere is developed to estimate changes in nitrous oxide (N2O) emissions from 1860–1990. The model is driven by four anthropogenic perturbations, including land use change and nitrogen inputs from fertilizer, livestock manure, and atmospheric deposition of fossil fuel NO x . Global soil nitrogen mineralization, volatilization, and leaching fluxes are estimated by the model and converted to N2O emissions based on broad assumptions about their associated N2O yields. From 1860–1990, global N2O emissions associated with soil nitrogen mineralization are estimated to have decreased slightly from 5.9 to 5.7 Tg N/yr, due mainly to land clearing, while N2O emissions associated with volatilization and leaching of excess mineral nitrogen are estimated to have increased sharply from 0.45 to 3.3 Tg N/yr, due to all four anthropogenic perturbations. Taking into account the impact of each perturbation on soil nitrogen mineralization and on volatilization and leaching of excess mineral nitrogen, global 1990 N2O emissions of 1.4, 0.7, 0.4 and 0.08 Tg N/yr are attributed to fertilizer, livestock manure, land clearing and atmospheric deposition of fossil fuel NO x , respectively. Consideration of both the short and long-term fates of fertilizer nitrogen indicates that the N2O/fertilizer-N yield may be 2% or more.C. NBM Definitions AET mon (cm H2O) = monthly actual evapotranspiration - AET ann (cm H2O) = annual actual evapotranspiration - age h (years) = stand age of herbaceous biomass - age w (years) = stand age of woody biomass - atmblc (gC/m2/month) = net flux of CO2 from grid - biotoc (gC/g biomass) = 0.50 = convert g biomass to g C - beff h = 0.8 = fraction of cleared herbaceous litter that is burned - beff w = 0.4 = fraction of cleared woody litter that is burned - bfmin = 0.5 = fraction of burned N litter that is mineralized or converted to reactive gases which rapidly redeposit. Remainder assumed pyrodenitrified to N2. + N2O - bprob = probability that burned litter will be burned - burn h (gC/m2/month) = herbaceous litter burned after land clearing - burn w (gC/m2/month) = woody litter burned after land clearing - cbiomsh (gC/m2) = C herbaceous biomass pool - cbiomsw (gC/m2) = C woody biomass pool - clear (gC/m2/month) = woody litter C removed by land clearing - clearn (gN/m2/month) = woody litter N removed by land clearing - cldh (month–1) = herbaceous litter decomposition coefficient - cldw (month–1) = woody litter decomposition coefficient - clittrh (gC/m2) = C herbaceous litter pool - clittrw (gC/m2) = C woody litter pool - clph (month–1) = herbaceous litter production coefficient - clpw (month–1) = woody litter production coefficient - cnrath (gC/gN) = C/N ratio in herbaceous phytomass - cnrats (gC/gN) = C/N ratio in soil organic matter - cnratt (gC/gN) = average C/N ratio in total phytomass - cnratw (gC/gN) = C/N ratio in woody phytomass - crod (month–1) = forest clearing coefficient - csocd (month–1) = actual soil organic matter decompostion coefficient - decmult decomposition coefficient multiplier; natural =1.0; agricultural =1.0 (1.2 in sensitivity test) - fertmin (gN/m2/month) = inorganic fertilizer input - fleach fraction of excess inorganic N that is leached - fligh (g Lignin/ g C) = lignin fraction of herbaceous litter C - fligw (g Lignin/ g C) = 0.3 = lignin fraction of woody litter C - fln2o = .01–.02 = fraction of leached N emitted as N2O - fnav = 0.95 = fraction of mineral N available to plants - fosdep (gN/m2/month) = wet and dry atmospheric deposition of fossil fuel NO x - fresph = 0.5 = fraction of herbaceous litter decomposition that goes to CO2 respiration - fresps = 0.51 + .068 * sand = fraction of soil organic matter decomposition that goes to CO2 respiration - frespw = 0.3 * (* see comments in Section 2.3 under decomposition) = fraction of woody litter decomposition that goes to CO2 respiration - fsoil = ratio of NPP measured on given FAO soil type to NPFmiami - fstruct = 0.15 + 0.018 * ligton = fraction of herbaceous litter going to structural/woody pool - fvn2o = .05–.10 = fraction of excess volatilized mineral N emitted as N2O - fvol = .02 = fraction of gross mineralization flux and excess mineral N volatilized - fyield ratio of total agricultural NPP in a given country in 1980 to total NPPmiami of all displaced natural grids in that country - gimmob h (gN/m2/month) = gross immobilization of inorganic N into microbial biomass due to decomposition of herbaceous litter - gimmob s (gN/m2/month) = gross immobilization of inorganic N into microbial biomass due to decomposition of soil organic matter - gimmob w (gN/m2/month) = gross immobilization of inorganic N into microbial biomass due to decomposition of woody litter - graze (gC/m2/month) = C herbaceous biomass grazed by livestock - grazen (gN/m2/month) = N herbaceous biomass grazed by livestock - growth h (gC/m2/month) = herbaceous litter incorporated into microbial biomass - growth w (gC/m2/month) = woody litter incorporated into microbial biomass - gromin h (gN/m2/month) = gross N mineralization due to decomposition and burning of herbaceous litter - gromin s (gN/m2/month) = gross N mineralization due to decomposition of soil organic matter - gromin w (gN/m2/month) = gross N mineralization due to decomposition and burning of woody litter - herb herbaceous fraction by weight of total biomass - leach (gN/m2/month) = leaching (& volatilization) losses of excess inorganic N - ligton (g lignin-C/gN) = lignin/N ratio in fresh herbaceous litter - LP h (gC/m2/month)= C herbaceous litter production - LP (gC/m2/month) = C woody litter production - LPN h (gN/m2/month) = N herbaceous litter production - LPN W (gN/m2/month) = N woody litter production - manco2 (gC/m2/month) = grazed C respired by livestock - manlit (gC/m2/month) = C manure input (feces + urine) - n2oint (gN/m2/month) = intercept of N2O flux vs gromin regression - n2oleach (gN/m2/month) = N2O flux associated with leaching and volatilization of excess inorganic N - n2onat (gN/m2/month) = natural N2O flux from soils - n2oslope slope of N2O flux vs gromin regression - nbiomsh (gN/m2) = N herbaceous biomass pool - nbiomsw (gN/m2) = N woody biomass pool - nfix (gN/m2/month) = N2 fixation + natural atmospheric deposition - nlittrh (gN/m2) = N herbaceous litter pool - nlittrw (gN/m2) = N woody litter pool - nmanlit (gN/m2/month) = organic N manure input (feces) - nmanmin (gN/m2/month) = inorganic N manure input (urine) - nmin (gN/m2) = inorganic N pool - NPP acth (gC/m2/month)= actual herbaceous net primary productivity - NPP actw (gC/m2/month) = actual woody net primary productivity - nvol (gN/m2/month) = volatilization losses from inorganic N pool - plntnav (gN/m2/month)= mineral N available to plants - plntup h (gN/m2/month) = inorganic N incorporated into herbaceous biomass - plntup w (gN/m2/month) = inorganic N incorporated into woody biomass - precip ann (mm) = mean annual precipitation - precip mon (mm) = mean monthly precipitation - pyroden h (gN/m2/month) = burned herbaceous litter N that is pyrodenitrified to N2 - pyroden w (gN/m2/month) = burned woody litter N that is pyrodenitrified to N2 - recyc fraction of N that is retranslocated before senescence - resp h (gC/m2/month) = herbaceous litter CO2 respiration - resp s (gC/m2/month) = soil organic carbon CO2 respiration - resp w (gC/m2/month) = woody litter CO2 respiration - sand sand fraction of soil - satrat ratio of maximum NPP to N-limited NPP - soiloc (gC/m2) = soil organic C pool - soilon (gN/m2) = soil organic N pool - temp ann (°C) = mean annual temperature - temp mon (°C) = mean monthly temperature Now at the NOAA Aeronomy Laboratory, Boulder, Colorado.  相似文献   

11.
Equitable access to sustainable development (EASD) is crucial for the future of the climate regime as it applies to adaptation, mitigation, and the means of implementation. An approach to allocating effort and deriving carbon budgets is presented here based on the United Nations Framework Convention on Climate Change (UNFCCC) principles of responsibility, capability, and sustainable development. A transparent model to operationalize EASD is applied by applying quantitative proxies for these criteria, and results for selected countries and groups are presented. A robust result is that the mitigation burden calculated by the model is significantly greater for developed than developing countries. For individual countries the results vary depending on the parameters chosen. A middle value of the mitigation burden for South Africa of 15 GtCO2e over the first half of the 21st century is reported, with the greatest effort required when a starting year of 1970 is chosen and historical land-use, land-use change and forestry (LULUCF) emissions are excluded when accounting for responsibility. In a regime applicable to all, it is clear that although all countries must do more, some must do more than others.

Policy relevance

Equitable access to sustainable development is crucial to the climate negotiations. Quantified allocations are presented for South Africa and other countries, based on the UNFCCC principles of responsibility, capability, and sustainable development. It is shown that the mitigation burden given these principles must be significantly greater for developed than developing countries. The results are relevant to, inter alia, the upcoming 2013–2015 review and the negotiations under the Durban Platform.  相似文献   

12.
Summary Frontogenesis is frequently described by theQ-vector (Hoskins et al., 1978), a term being composed of several derivatives of basic meteorological parameters and their products. Its distribution and especially the H ·Q-fields are highly important to estimate frontogenesis and cross frontal circulation. Although theQ-vector (Hoskins et al., 1978) allows an easier assessment of the vertical wind forcing than the original omega equation of the quasi-geostrophic theory, it is still difficul to imagine the three-dimensional (3-d) spatial distribution ofQ and H ·Q even for standard atmospheric fields. Thus there is a need to shed more light in theQ and H ·Q-fields for special synoptic situations.This is done here by constructing analytical 3-d geostrophically balanced wind-and temperature fields, for which theQ-forcing (Qformed with the geostrophic wind) can easily be computed and presented. Three examples (see Sections 3 to 5) are discussed yielding typical and realistic (compared to known pattern) 3-d forcing distributions ofQ and H ·Q. Within the simple analytical scheme used here their origin can casily be understood. These fields of a 2000×2000 km2 horizontal domain ranging up to 250 hPa are: A modified Bergeron deformation field containing a cold front (case I a) and a warm front (case I b); an upper tropospheric jet including a jet-parallel transition zone between warm and cold air (case II); and a circular low pressure circulation pattern with two fronts (case III).The paper presents these 3-d fields with the advantage that the analytical method is not affected by any kind of limited numerical resolution. It also shows how these fields degenerate with decreasing resolution if the analytical data are used in descrete form. This simulates working with discrete numerical data and demonstrates how narrow frontal zones of structure elements ofQ and H ·Q considerably smooth out with increasing grid distances.With 17 Figures  相似文献   

13.
《大气与海洋》2012,50(4):307-317
ABSTRACT

This study investigates the response of the subtropical gyre circulation in the North Pacific Ocean to quadrupled CO2 using the Community Earth System Model, version 1 (CESM1). In particular, an overriding technique is applied to isolate and quantify the effects of wind stress and thermal warming caused by CO2 emissions. Results show that, in response to the increase in CO2, the total mass transport in the subtropical gyre is reduced by approximately 11%. This reduction results mainly from negative anomalies of the wind stress curl over the subtropical region, with a smaller contribution from the thermal warming effect. Furthermore, a detailed analysis finds that the change in the subtropical gyre is baroclinic in nature [i.e., the gyre appears to be spin-up in the upper ocean (above 300?m) but spin-down in the lower thermocline (from 300 to 1500?m)]. This reversal between the upper ocean and lower thermocline is a result of the thermal warming effect, which intensifies ocean stratification, hindering the transfer of momentum from the upper layers to the lower layers and leading to an acceleration of the gyre in the upper ocean but a deceleration in the lower thermocline. Another feature of the response of the subtropical gyre to quadrupled CO2 is the respective poleward and equatorward movements of its northern and southern boundaries, which is a result of the change in the zero wind stress curl lines.  相似文献   

14.
Summary ?The performance of the Penman-Monteith (PM) equation to estimate daily reference evapotranspiration (ETO) was investigated by attributing three distinct features to the canopy resistance (r c): (i) r c constant at 70 s m−1 (Allen et al., 1998; FAO Irrigation and Drainage Paper n. 56), (ii) r c variable as linear function of a critical resistance r c, depending on weather variables and empirical parameters relating r c to r * (Katerji and Perrier, 1983; Agronomie, 3[6]: 513–521) and (iii) r c variable as a mechanistic function of weather variables only (Todorovic, 1999; J. Irrig. Drainage Eng., ASCE, 125[5]: 235–245). Daily weather and grass lysimeter data, measured for a period of seven years at Policoro (Southern Italy), were used. The results confirmed the relative robustness of the PM method with constant r c while better estimates were obtained only when variable r c was used. The mechanistic approach of Todorovic (1999) provided the best estimates, while the approach of Katerji and Perrier (1983), with empirically derived parameters, has shown to be not conservative enough to be extended to different locations without calibration. Received January 2, 2002; revised October 31, 2002; accepted December 7, 2002  相似文献   

15.
A recent study has shown that Foxe Basin's dense waters originate from coastal latent heat polynyas and each year replace 2/3rd of the basin's deep waters by propagating southeastwards in Foxe Channel as a gravity current. The formation mechanisms in 2004 of these dense waters are examined here. Strong meteorological events occurring in mid-winter over the domain are responsible for the simultaneous opening of two large polynyas at Lyon Inlet and along Melville Peninsula's eastern coast while a third important and recurrent polynya opens earlier at Hall Beach (northwestern Foxe Basin). Large sea-atmosphere heat exchanges take place in these polynyas, leading to the production of 21.2 × 1012 kg of sea-ice and 1.53 × 1012 m3 of dense water. The ice production rate is on average five to six times higher in the polynyas than in the rest of the basin. Following the topography, the dense waters formed at Hall Beach and along Melville Peninsula cascade into Foxe Channel, while those produced at Lyon Inlet sink directly in the channel through deep convection. The two mechanisms synchronize and combine together when Lyon Inlet and Melville Peninsula polynyas open up. The heat exchanges, sea-ice and brine production rates estimated with a 21-year near-climatology are similar to those found in 2004. The results also show that the produced dense waters can overflow into Hudson Bay.  相似文献   

16.
Abstract

Aqueous‐phase H2O2 production in a rainband and its possible effect on sulphate production are studied by means of a two‐dimensional numerical model. In‐cloud peroxide production is incorporated into this chemistry model and its simulation results are compared with those in which aqueous‐phase H2O2 came only from the dissolution of gaseous H2O2 from the cloud interstitial air.

Results are presented for two different polluted situations ‐ Case 1 having initial SO2 and sulphate aerosol profiles representative of a moderately polluted air mass, and Case 2 having chemical profiles expected to increase the relative importance of oxidation to nucleation as a means of contributing sulphate to cloud and rain. Sulphate production increased in both cases, although in Case 1 the effect of this increase on the concentration of sulphate in rain is negligible because nucleation and scavenging of aerosol are the major processes by which sulphate enters cloud and rain. In Case 2, sulphate concentrations in rain increase by 5–10%. Under environmental conditions of low sulphate aerosol, where oxidation reactions are the dominant means for sulphate to enter cloud and rain, the neglect of sulphate produced by the additional H2O2 may lead to error. The usual uncertainties in the initial SO2 and sulphate aerosol vertical profiles, however, could be a more significant source of error in simulations of the chemistry of cloud and precipitation than the neglect of aqueous‐phase peroxide production during the lifetime of even a long‐lived system.  相似文献   

17.
The MAGICC (Model for the Assessment of Greenhouse gas Induced Climate Change) model simulation has been carried out for the 2000–2100 period to investigate the impacts of future Indian greenhouse gas emission scenarios on the atmospheric concentrations of carbon dioxide, methane and nitrous oxide besides other parameters like radiative forcing and temperature. For this purpose, the default global GHG (Greenhouse Gases) inventory was modified by incorporation of Indian GHG emission inventories which have been developed using three different approaches namely (a) Business-As-Usual (BAU) approach, (b) Best Case Scenario (BCS) approach and (c) Economy approach (involving the country’s GDP). The model outputs obtained using these modified GHG inventories are compared with various default model scenarios such as A1B, A2, B1, B2 scenarios of AIM (Asia-Pacific Integrated Model) and P50 scenario (median of 35 scenarios given in MAGICC). The differences in the range of output values for the default case scenarios (i.e., using the GHG inventories built into the model) vis-à-vis modified approach which incorporated India-specific emission inventories for AIM and P50 are quite appreciable for most of the modeled parameters. A reduction of 7% and 9% in global carbon dioxide (CO2) emissions has been observed respectively for the years 2050 and 2100. Global methane (CH4) and global nitrous oxide (N2O) emissions indicate a reduction of 13% and 15% respectively for 2100. Correspondingly, global concentrations of CO2, CH4 and N2O are estimated to reduce by about 4%, 4% and 1% respectively. Radiative forcing of CO2, CH4 and N2O indicate reductions of 6%, 14% and 4% respectively for the year 2100. Global annual mean temperature change (incorporating aerosol effects) gets reduced by 4% in 2100. Global annual mean temperature change reduces by 5% in 2100 when aerosol effects have been excluded. In addition to the above, the Indian contributions in global CO2, CH4 and N2O emissions have also been assessed by India Excluded (IE) scenario. Indian contribution in global CO2 emissions was observed in the range of 10%–26%, 6%–36% and 10%–38% respectively for BCS, Economy and BAU approaches, for the years 2020, 2050 and 2100 for P50, A1B-AIM, A2-AIM, B1-AIM & B2-AIM scenarios. CH4 and N2O emissions indicate about 4%–10% and 2%–3% contributions respectively in the global CH4 and N2O emissions for the years 2020, 2050 and 2100. These Indian GHG emissions have significant influence on global GHG concentrations and consequently on climate parameters like RF and ∆T. The study reflects not only the importance of Indian emissions in the global context but also underlines the need of incorporation of country specific GHG emissions in modeling to reduce uncertainties in simulation of climate change parameters.  相似文献   

18.
Abstract

A series of meetings of two ‘Citizen Panels’ were held to explore public perceptions of off-shore carbon dioxide (CO2) capture and storage (CCS). In addition, a face-to-face survey of 212 randomly selected individuals was conducted. We found that, on first hearing about CCS in the absence of any information on its purpose, the majority of people either do not have an opinion at all or have a somewhat negative perspective. However, when (even limited) information is provided on the role of CO2 storage in reducing CO2 emissions to the atmosphere, opinion shifts towards expressing slight support for the concept.

Support depends, however, upon concern about human-caused climate change, plus recognition of the need for major reductions in CO2 emissions. It also depends upon CCS being seen as just one part of a wider strategy for achieving significant cuts in CO2 emissions. A portfolio including renewable energy technologies, energy efficiency, and lifestyle change to reduce demand was generally favoured. CCS can be part of such a portfolio, but wind, wave, tidal, solar and energy efficiency were preferred. It was felt that uncertainties concerning the potential risks of CCS had to be better addressed and reduced; in particular the risks of accidents and leakage (including the potential environmental, ecosystem and human health impacts which might result from leakage).  相似文献   

19.
ABSTRACT

The inherently global, connected nature of aviation means that carbon leakage from aviation policy does not necessarily behave similarly to leakage from other sectors. We model carbon leakage from a range of aviation policy test cases applied to a specific country (the United Kingdom), motivated by a desire to reduce aviation CO2 faster than achievable by currently-planned global mitigation efforts in pursuit of a year-2050 net zero CO2 target. We find that there are two main components to leakage: one related to passenger behaviour, which tends to result in emissions reductions outside the policy area (negative leakage), and one related to airline behaviour, which tends to result in emissions increases outside the policy area (positive leakage). The overall leakage impact of a policy, and whether it is positive or negative, depends on the balance of these two components and the geographic scope used, and varies for different policy types. In our simulations, carbon pricing-type policies were associated with leakage of between +50 and ?150% depending on what is assumed about scope and the values of uncertain parameters. Mandatory biofuel use was associated with positive leakage of around 0–40%, and changes in airport landing costs to promote more fuel-efficient aircraft were associated with positive leakage of 50–150%.

Key policy insights

  • Carbon leakage in aviation policy arises from airline responses (typically positive leakage) and passenger responses (typically negative leakage).

  • Depending on the geographical scope, policy type and values for uncertain parameters, leakage may be between around ?150 to +150%.

  • Of the policies investigated in this study, leakage was typically most negative for carbon pricing and most positive for environmental landing charges.

  • Absolute values of leakage are smallest where policies are considered on the basis of all arriving and departing flights.

  相似文献   

20.
Abstract

Cloud amount records for the Canadian mid‐latitudes have been analysed in the context of a “warming world” analogue model that compares records of two 20‐year periods. The cloud amounts increase over practically all these regions while temperatures rise. This historical data set has also been extended temporally to permit analysis of high‐latitude cloudiness trends. These are of particular interest in the “fingerprinting” of CO2‐induced climatic change. Station records from the Canadian Arctic show distinctive increases in total cloud amount in the last forty years especially in the summer season. This result, unlike the historical analogue analysis, seems to be decoupled from temperature changes.  相似文献   

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