南京和长三角地区CO_2与CH_4人为排放清单估算的不确定性分析

目前温室气体清单的编制主要基于IPCC方法,该方法用于特定城市或区域清单编制时可能会引起较大的不确定性,而目前对城市/区域尺度清单的不确定性的分析还存在很大的欠缺。本文通过南京市和长三角温室气体排放因子甄选,应用IPCC方法计算了2009年南京市和长三角的人为温室气体排放量,并以其为个例利用蒙特卡洛方法开展城市和区域尺度的温室气体人为排放清单不确定性的初步探究。研究结果表明:南京市CH4和CO2排放量的95%的概率分布范围分别为(1.08~1.86)×105t和(6.50~7.41)×107t,不确定性分别为-21.74%~34.78%和-7.01%~5.87%;长三角CH4和CO2排放量的95%的概率分布范围分别为(4.07~5.89)×106t和(1.62~1.82)×109t,不确定性分别为-15.60%~22.24%和-6.04%~5.34%。     

Seasonal Variations of CH_4 Emissions in the Yangtze River Delta Region of China Are Driven by Agricultural Activities

Developed regions of the world represent a major atmospheric methane(CH_4) source, but these regional emissions remain poorly constrained. The Yangtze River Delta(YRD) region of China is densely populated(about 16% of China's total population) and consists of large anthropogenic and natural CH_4 sources. Here, atmospheric CH_4 concentrations measured at a 70-m tall tower in the YRD are combined with a scale factor Bayesian inverse(SFBI) modeling approach to constrain seasonal variations in CH_4 emissions. Results indicate that in 2018 agricultural soils(AGS, rice production) were the main driver of seasonal variability in atmospheric CH_4 concentration. There was an underestimation of emissions from AGS in the a priori inventories(EDGAR—Emissions Database for Global Atmospheric Research v432 or v50), especially during the growing seasons. Posteriori CH_4 emissions from AGS accounted for 39%(4.58 Tg, EDGAR v432) to 47%(5.21 Tg, EDGAR v50) of the total CH_4 emissions. The posteriori natural emissions(including wetlands and water bodies) were1.21 Tg and 1.06 Tg, accounting for 10.1%(EDGAR v432) and 9.5%(EDGAR v50) of total emissions in the YRD in2018. Results show that the dominant factor for seasonal variations in atmospheric concentration in the YRD was AGS,followed by natural sources. In summer, AGS contributed 42%(EDGAR v432) to 64%(EDGAR v50) of the CH_4 concentration enhancement while natural sources only contributed about 10%(EDGAR v50) to 15%(EDGAR v432). In addition, the newer version of the EDGAR product(EDGAR v50) provided more reasonable seasonal distribution of CH_4 emissions from rice cultivation than the old version(EDGAR v432).     

中国平流层CH4的分布特征和季节变化

利用UARS卫星上HALOE试验的1992—2003年CH4资料,分析了中国平流层的CH4混合比分布特征,并对CH4混合比在不同纬度上的季节变化作了详细分析。结果表明,中国平流层CH4混合比随着高度逐渐减小,在经向上有较大差异,总是南边大于北边,而各个纬度带上的分布则较均匀。分析结果还表明,中国平流层CH4混合比在DJF的季节距平与MAM有相反的符号,而且中心位置基本吻合。此外,季节变率最大的是MAM—DJF,而不是JJA—DJF。并且在平流层低层的夏半年有明显的高值带,这可能与上升运动和辐散辐合作用有关。     

Estimate of Hydrofluorocarbon Emissions for 2012–16 in the Yangtze River Delta,China

Hydrofluorocarbons(HFCs) have been widely used in China as substitutes for ozone-depleting substances,the production and use of which are being phased out under the Montreal Protocol.China is a major consumer of HFCs around the world,with its HFC emissions in CO_2-equivalent contributing to about 18% of the global emissions for the period2012-16.Three methods are widely used to estimate the emissions of HFCs-namely,the bottom-up method,top-down method and tracer ratio method.In this study,the tracer ratio method was adopted to estimate HFC emissions in the Yangtze River Delta(YRD),using CO as a tracer.The YRD region might make a significant contribution to Chinese totals owing to its rapid economic growth.Weekly flask measurements for ten HFCs(HFC-23,HFC-32,HFC-125,HFC-134 a,HFC-143 a,HFC-152 a,HFC-227 ea,HFC-236 fa,HFC-245 fa and HFC-365 mfc) were conducted at Lin'an Regional Background Station in the YRD over the period 2012-16,and the HFC emissions were 2.4±1.4 Gg yr~(-1) for HFC-23,2.8±1.2 Gg yr~(-1) for HFC-32,2.2±1.2 Gg yr~(-1) for HFC-125,4.8±4.8 Gg yr~(-1) for HFC-134 a,0.9±0.6 Gg yr~(-1) for HFC-152 a,0.3±0.3 Gg yr~(-1) for HFC-227 ea and 0.3±0.2 Gg yr~(-1) for HFC-245 fa.The YRD total HFC emissions reached 53 Gg CO_2-e yr~(-1),contributing 34% of the national total.The per capita HFC CO_2-equivalent emissions rate was 240 kg yr-1,while the values of per unit area emissions and per million GDP emissions reached 150 Mg km~(-2)yr~(-1) and 3500 kg yr~(-1)(million CNY GDP)-1,which were much higher than national or global levels.     

中国废水处理甲烷排放特征和减排潜力分析

废弃物处理温室气体排放的主要排放源之一为废水（生活污水和工业废水）处理CH₄排放。根据统计资料和IPCC提供的方法,选择适合中国的排放因子,分析了中国废水处理2005-2010年的CH₄排放特征和2000-2010年CH₄产生的各驱动因子。并且根据中国的实际情况预测和分析了中国废水处理CH₄排放趋势和排放潜力。结果显示：2010年中国生活污水处理CH₄排放量为61.10万t,工业废水处理的CH₄排放量为162.37万t,造纸等八大行业CH₄排放量达到总CH₄排放量的92%以上,2005-2010年的CH₄排放量逐年增加;到2020年在减排情景下,生活污水处理CH₄排放量为101.36万t,减排潜力为7.63万t,比2010年排放量增加了66%;工业废水处理CH₄排放量233.93万t,减排潜力为25.99万t,比2010年排放量增加了44%。     

A simple model for estimating methane concentration and lifetime variations

A simple methane model is presented in which lifetime changes are expressed as a function of CH₄ concentration and emissions of NO_x CO and NMHCs. The model parameters define the relative sensitivities of lifetime to these determining factors. The parameterized model is fitted to results from five more complex atmospheric chemistry models and to 1990 IPCC concentration projections. The IPCC data and four of the five models are well fitted, implying that the models have similar relative sensitivities. However, overall sensitivities of lifetime to changes in atmospheric composition vary widely from model to model. The parameterized model is used to estimate the history of past methane emissions, lifetime changes and OH variations, with estimates of uncertainties. The pre-industrial lifetime is estimated to be 15–34% lower than today. This implies that 23–55% of past concentration changes are due to lifetime changes. Pre-industrial emissions are found to be much higher (220–330 TgCH₄/y) than the best estimate of present natural emissions (155 TgCH₄/y). The change in emissions since pre-industrial times is estimated to lie in the range 160–260 TgCH₄/y, compared with the current best guess for anthropogenic emissions of 360 TgCH₄/y. These results imply either that current estimates of anthropogenic emissions are too high and/or that there have been large changes in natural emissions. 1992 IPCC emissions scenarios are used to give projections of future concentration and lifetime changes, together with their uncertainties. For any given emissions scenario, these uncertainties are large. In terms of future radiative forcing and global-mean temperature changes over 1990–2100 they correspond to uncertainties of at least ±0.2 Wm^–2 and ± 0.1° C, respectively.     

The marginal impacts of CO2, CH4 and SF6 emissions

Abstract

A new version of the PAGE model, PAGE2002, has been used to calculate the marginal impacts of CO₂, CH₄ and SF₆ emissions based on Scenario A2 of the IPCC. The mean marginal impact of CO₂ is found to be US$19 per tonne of carbon (or about US$5 per tonne of CO₂), for methane it is US$105 per tonne, and for SF₆ it is US$200,000 per tonne. For each gas, the range between the 5% and 95% points is about an order of magnitude. The climate change impacts of methane are a significant proportion of its market price, and for SF₆ the climate change impacts are much larger than the market price. The economics of schemes to reduce the leakage of SF₆ are transformed once the climate change impacts are properly counted.     

大气中微量气体的红外吸收

文章介绍了测定大气中微量气体CO2与CH4透过率的试验。所用的主要设备是FTIR分光计及可变光程吸收池。文中叙述了主要实验结果与数据处理方法，同时用FASCODE-2程序计算了对应实验条件下CO2与CH4的透过率，并与实验结果作了比较。     

IPCC确定的几种未来大气CO2浓度水平对人为CO2排放的限制

用三维海洋碳循环模式和一个简单的陆地生物圈模式计算了IPCC(政府间气候变化委员会)未来大气CO2情景中海洋和生物圈的吸收,并结合土地变化的资料得出燃料的排放值。结果表明：尽管在所有的构想下,为了使大气中CO2浓度达到稳定必须减少排放,但对应不同的IPCC未来大气CO2情景,对人为CO2排放的限制是很不相同的。     

Coupling biophysical and micro-economic models to assess the effect of mitigation measures on greenhouse gas emissions from agriculture

Agricultural soils are a major source of atmospheric nitrous oxide (N₂O), a potent greenhouse gas (GHG). Because N₂O emissions strongly depend on soil type, climate, and crop management, their inventory requires the combination of biophysical and economic modeling, to simulate farmers’ behavior. Here, we coupled a biophysical soil-crop model, CERES-EGC, with an economic farm type supply model, AROPAj, at the regional scale in northern France. Response curves of N₂O emissions to fertilizer nitrogen (Nf) inputs were generated with CERES-EGC, and linearized to obtain emission factors. The latter ranged from 0.001 to 0.0225 kg N₂O-N kg^???1 Nf, depending on soil and crop type, compared to the fixed 0.0125 value of the IPCC guidelines. The modeled emission factors were fed into the economic model AROPAj which relates farm-level GHG emissions to production factors. This resulted in a N₂O efflux 20% lower than with the default IPCC method. The costs of abating GHG emissions from agriculture were calculated using a first-best tax on GHG emissions, and a second-best tax on their presumed factors (livestock size and fertilizer inputs). The first-best taxation was relatively efficient, achieving an 8% reduction with a tax of 11 €/ t-CO₂-equivalent, compared to 68 €/t-CO₂ eq for the same target with the second-best scheme.     

基于排放源的中国城市垃圾填埋场甲烷排放研究

利用全国垃圾填埋场的点源数据,基于实际调研和实验室分析建立中国不同区域、不同规模、不同填埋时间的排放因子矩阵,采用IPCC推荐的一级降解动力学（FOD）方法自下而上地核算了中国2107个垃圾填埋场在2007年的甲烷（CH₄）排放量。针对不同区域和类型的填埋场,分别就城市垃圾组分、可降解有机碳、CH₄修正因子、CH₄氧化系数、填埋场CH₄收集率等进行了深入研究。结果显示,中国2007年填埋场CH₄排放量为118.61万t,与《中华人民共和国气候变化第二次国家信息通报》2005年填埋场排放量（220万t）差异较大,其主要原因是城市垃圾填埋场统计数据的差异,例如填埋场个数及垃圾填埋量。中国绝大部分填埋场CH₄年排放量在700 t以下,超过1000 t的有279个,超过1万t的仅10个。江苏省的CH₄排放量最高,达到9.87万t;西藏的排放量最小,仅为0.21万t。东部江苏、广东、浙江等省的整体排放量较高,西部地区西藏、宁夏、青海等地的排放水平较低。     

Present and future climates of the Greenland ice sheet according to the IPCC AR4 models

The atmosphere?Cocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited AOGCMs for Greenland climate simulation are then selected on the basis of comparison between the 1970?C1999 outputs of the Climate of the twentieth Century experiment (20C3M) and reanalyses (ECMWF, NCEP/NCAR). This comparison indicates that the representation quality of surface parameters such as temperature and precipitation are highly correlated to the atmospheric circulation (500?hPa geopotential height) and its interannual variability (North Atlantic oscillation). The outputs of the three most suitable AOGCMs for present-day climate simulation are then used to assess the changes estimated by three IPCC greenhouse gas emissions scenarios (SRES) over the GrIS for the 2070?C2099 period. Future atmospheric circulation changes are projected to dampen the zonal flow, enhance the meridional fluxes and therefore provide additional heat and moisture to the GrIS, increasing temperature over the whole ice sheet and precipitation over its northeastern area. We also show that the GrIS surface mass balance anomalies from the SRES A1B scenario amount to ?300?km³/year with respect to the 1970?C1999 period, leading to a global sea-level rise of 5?cm by the end of the 21st century. This work can help to select the boundaries conditions for AOGCMs-based downscaled future projections.     

RESPONSES OF A GLOBAL CGCM TO CO_2 INCREASE

The responses of the climate system to increase of atmospheric carbon dioxide(CO_2)arestudied by using a new version of the Bureau of Meteorological Research Centre(BMRC)globalcoupled general circulation model(CGCM).Two simulations are run:one with atmospheric CO_2concentration held constant at 330 ppm,the other with a tripling of atmospheric CO_2(990 ppm).Results from the 41-year control coupled integration are applied to analyze the mean state,seasonal cycle and interannual variability in the model.Comparisons between the greenhouseexperiment and the control experiment then provide estimations of the influence of increased CO_2on climate changes and climate variability.Especially discussed is the question on whether theclimate changes concerned with CO_2 inerease will impact interannual variability in tropical Pacific,such as ENSO.     

Estimates of global N2O emissions from cattle, pig and chicken manure, including a discussion of CH4 emissions

Humans seem to have doubled the global rate of terrestrial nitrogen fixation. Globally 50–70% (85 Tg, 1 Tg=10¹² g) of the nitrogen supplied in fertilizer (80 Tg N/a) and leguminous crops (40–80 Tg N/a) are used to feed cattle. The aim of the present study was to derive some estimates of global N₂O production from animal manure. As the parameter giving the most stable numerical basis for regional and global extrapolation we adopted the molar emission ratios of N₂O to NH₃. These ratios were measured in cattle, pig and chicken housings with different manure handling systems, in dung-heaps and in liquid manure storage tanks. Individual molar emission ratios from outside manure piles varied over two orders of magnitude, strongly dependent on the treatment of the manure. A median emission ratio of 1.6×10^-2 (n=65) was obtained in cow-sheds with slatted floors and liquid manure stored underneath and a median ratio of 24×10^-2 (n=31) was measured in a beef cattle housing with a solid manure handling system.We next extrapolated to global NH₃ emissions from those estimated for Europe, using N uptake by the animals as a scaling factor. Multiplication with observed N₂O to NH₃ ratios next provided some estimates of regional and global N₂O emissions. To account for the great variability of the emission ratios of N₂O/NH₃, we developed upper and lower case emission scenarios, based on lower and upper quartiles of measured emission ratios. The global emission from cattle and swine manure is in the range of 0.2–2.5 Tg N-N₂O/a, representing 44+-39% of the annual atmospheric accumulation rate. This N₂O emission arises from about 40 Tg N/a of cattle and pig manure stored in or at animal housings. We did not account for N₂O emissions from another 50 Tg N/a excreted by grazing cattle, goats and sheep, and application of the manure to agricultural fields. Our study makes it clear that major anthropogenic N₂O emissions may well arise from animal manure. The large uncertainty of emission ratios, which we encountered, show that much more intense research efforts are necessary to determine the factors that influence N₂O emissions from domestic animal manure both in order to derive a more reliable global estimate of N₂O release and to propose alternative waste treatment methods causing smaller N₂O releases. In our studies we found large enhancements in N₂O releases when straw was added to the manure, which is a rather common practice. In view of the ongoing discussion in Europe to re-install the traditional solid manure system (bed down cattle) for environmental and animal welfare reasons, it is noteworthy that our measurements indicate highest N₂O release from this particulary system.In a similar manner, but based on a smaller data set, we also estimated the release of CH₄ from cattle and swine manure and from liquid manure only to be about 9 Tg/year in good agreement with the estimate by the Environmental Protection Agency (1994) of 8.6+-2.6 Tg/year. A total annual methane release as high as 34 Tg/a was derived for solid and liquid cattle and pig manure from animals in housings.     

基于灰色关联模型的南京市碳排放驱动因素研究

全球气候变暖已经成为不争的事实,人们逐渐认识到依靠大量能源消费的生产方式、不惜牺牲环境的经济增长模式、无节制大量消费的生活方式应该从根本上得到改变.城市作为工业、建筑、交通的载体,也是高能耗、高碳排放的主要源头,需要改变传统城市发展的模式来应对全球变暖的挑战,发展低碳城市被认为是未来最有希望的经济发展动力.首先采用IPCC能源转换模型对南京市碳排量进行测算,选取南京的人口数量、GDP、人均GDP、人口城市化率、产业结构多元化系数（ESD）、能源消费结构多元化系数（ESCD）和能源强度作为对比数列,以南京CO₂排放总量作为参考数列,运用灰色系统关联模型进行关联度计算并排序.结果显示,南京市碳排放量关联度从大到小依次为ESD、人口数量、城市化率、ECSD、能源强度、人均GDP、GDP,这与南京工业生产因化石能源的大量使用对城市碳排放量贡献占总排量一半以上的分析结果相吻合.最后详细分析各指标对南京建设低碳城市的影响,并提出对策建议.     

A national landfill methane budget for Sweden based on field measurements, and an evaluation of IPCC models

Seven Swedish landfills were investigated from 2001 to 2003. On each landfill, a measure of the total methane production was calculated from data on: (1) methane emissions (leakage); (2) methane oxidation and (3) from gas recovery.
Methane emissions were determined via a tracer gas (N₂O) release-based remote sensing method. N₂O and CH₄ were measured with an Fourier Transform infrared detector at a distance of more than 1 km downwind from the landfills. Methane oxidation in the landfill covers was measured with the stable carbon isotope method. The efficiency in gas recovery systems proved to be highly variable, but on an average, 51% of the produced landfill gas was captured.
A first-order decay model, based on four fractions (waste from households and parks, sludges and industrial waste), showed that the use of a degradable organic carbon fraction (DOCf) value of 0.54, in accordance with the default value for DOCf of 0.50 in the latest IPCC model, gave an emission estimate similar to the official national reports.     

长江三角洲梅汛期降水与大气环流季节内演变的关系及延伸期预报

基于1981—2020年长江三角洲(简称长三角)地区62个国家基本气象站的逐日降水量资料及NCEP/NCAR全球大气逐日再分析资料,分析了长三角地区梅汛期降水与前期大气环流季节内协同演变的关系,在此基础上利用改进的时空投影方法(STPM)构建了针对该地区梅汛期降水的延伸期预报模型.结果表明:(1)长三角地区梅汛期降水存...     

A Local-Scale Study of the Trace Gas Emissions from Vegetation Burning around the Village of Dalun, Ghana, with Respect to Seasonal Vegetation Changes and Burning Practices

The annual trace gas emissions from a West African rural region were calculated using direct observations of gas emissions and burning practices, and the findings compared to the guidelines published by the IPCC. This local-scale study was conducted around the village of Dalun in the Northern Region of Ghana, near the regional capital of Tamale. Two types of fires were found in the region – agricultural fires andwildfires. Agricultural fires are intentionally set in order to remove shrub and crop residues; wildfires are mostly ignited by herders to remove inedible grasses and to promote the growth of fresh grass. An agricultural fire is ignited with a fire front moving against the wind (backfire), whereas a wildfire moves with the wind (headfire). Gas emissions (CO₂, CO and NO) weremeasured by burning eight experimental plots, simulating both headfires and backfires. A common method of evaluating burning conditions is to calculate modified combustion efficiency (MCE), which expresses the percentage of the trace gases released as CO₂. Modified combustion efficiency was95% in the wildfires burned as headfires, but only 90% in the backfires.The burned area in the study region was determined by classifying a SPOT HRV satellite image taken about two months into the dry season. Fires were classified as either old burned areas or new burned areas as determined by the gradient in moisture content in the vegetation from the onset of the dry season. Classified burned areas were subsequently divided into two classes depending on whether the location was in the cultivated area or in the rangeland area, this sub-classification thus indicating whether the fire had been burned as a backfire or headfire. Findings showed that the burned area was 48% of the total region, and that the ratio of lowland wildfiresto agricultural fires was 3:1. The net trace gas release from the classified vegetation burnings were extrapolated to 26–46×10⁸ gCO₂, 78–302×10⁶ g CO,17–156×10⁵ g CH₄,16–168×10⁵ g NMHC and 11–72×10³ NO_x. Calculation of the emissionsusing proposed IPCC default values on burned area and average biomass resulted in a net emission 5 to 10 times higher than the measured emission values. It was found that the main reason for this discrepancy was not the emission factorsused by the IPCC, but an exaggerated fuel load estimate.     

A projection of extreme climate events in the 21st century over east Asia using the community climate system model 3

A series of coupled atmosphere-ocean-land global climate model (GCM) simulations using the National Center for Atmospheric Research (NCAR) Community Climate System Model 3 (CCSM3) has been performed for the period 1870–2099 at a T85 horizontal resolution following the GCM experimental design suggested in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). First, a hindcast was performed using the atmospheric concentrations of three greenhouse gases (CO₂, CH₄, N₂O) specified annually and globally on the basis of observations for the period 1870–1999. The hindcast results were compared with observations to evaluate the GCM’s reliability in future climate simulations. Second, climate projections for a 100-year period (2000–2099) were made using six scenarios of the atmospheric concentrations of the three greenhouse gases according to the A1FI, A1T, A1B, A2, B1, and B2 emission profiles of the Special Report on Emissions Scenarios. The present CCSM simulations are found to be consistent with IPCC’s AR4 results in the temporal and spatial distributions for both the present-day and future periods. The GCM results were used to examine the changes in extreme temperatures and precipitation in East Asia and Korea. The extreme temperatures were categorized into warm and cold events: the former includes tropical nights, warm days, and heat waves during summer (June–July–August) and the latter includes frost days, cold days, and cold surges during winter (December–January–February). Focusing on Korea, the results predict more frequent heat waves in response to future emissions: the projected percentage changes between the present day and the late 2090s range from 294% to 583% depending on the emission scenario. The projected global warming is predicted to decrease the frequency of cold extreme events; however, the projected changes in cold surge frequency are not statistically significant. Whereas the number of cold surges in the A1FI emission profile decreases from the present-day value by up to 24%, the decrease in the B1 scenario is less than 1%. The frequency and intensity of extreme precipitation events year-round were examined. Both the frequency and the intensity of these events are predicted to increase in the region around Korea. The present results will be helpful for establishing an adaptation strategy for possible climate change nationwide, especially extreme climate events, associated with global warming.     

东亚地区小冰期气候的模拟

本文使用ECHO-G全球气候模式对1550～1850年的小冰期气候进行了300个模式年的模拟,着重分析了东亚地区小冰期的温度变化特征,并与目前所得到的小冰期气候重建结果进行了对比。结果表明,在考虑了太阳辐射、火山活动、CO2和CH4等主要气候影响驱动因子的条件下,较好地模拟出了东亚地区的小冰期气候特征,并与其它手段的气候重建结果相吻合,显示太阳活动和火山活动是小冰期气候形成的主要原因。