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1.
A review on the generation, determination and mitigation of Urban Heat Island   总被引:21,自引:1,他引:21  
Urban Heat Island (UHI) is considered as one of the major problems in the 21st century posed to human beings as a result of urbanization and industrialization of human civilization. The large amount of heat generated from urban structures, as they consume and re-radiate solar radiations, and from the anthropogenic heat sources are the main causes of UHI. The two heat sources increase the temperatures of an urban area as compared to its surroundings, which is known as Urban Heat Island Intensity (UHII). The problem is even worse in cities or metropolises with large population and extensive economic activities. The estimated three billion people living in the urban areas in the world are directly exposed to the problem, which will be increased significantly in the near future. Due to the severity of the problem, vast research effort has been dedicated and a wide range of literature is available for the subject. The literature available in this area includes the latest research approaches, concepts, methodologies, latest investigation tools and mitigation measures. This study was carded out to review and summarize this research area through an investigation of the most important feature of UHI. It was concluded that the heat re-radiated by the urban structures plays the most important role which should be investigated in details to study urban heating especially the UHI. It was also concluded that the future research should be focused on design and planning parameters for reducing the effects of urban heat island and ultimately living in a better environment.  相似文献   

2.
Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 198.5 to 1999 rapidly developed which showed a difference of mean temperature above 2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings. The mean temperature of the residential and commercial areas in the study was found to be 4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island.  相似文献   

3.
Trend and seasonal variations of atmospheric CH4 in Beijing   总被引:1,自引:0,他引:1  
The atmospheric CH4 in Beijing is still increasing, even though its increasing rate has significantly decreased from 1.76 %/a during 1985-1989 to 0.50 %/a during 1990-1997. The seasonal variation of CH4 concentration showed a double-peak pattern, one peak appearing in winter and the other in summer. It is evident that the annually seasonal variations of atmospheric CH4 in Beijing are different. From 1986 to 1997, the atmospheric CH4 increased by 185 ppbv, 37% and 21% of which were due to the increase in winter and in summer, respectively. After 1993, the annually seasonal increasing rate of CH4 concentration in summer (due to emission from biogenic sources) is negative while the increasing rate in winter (due to emission from non-biogenic sources) is positive about 25 ppbv/a. As a result, the increase of CH4 emission from non-biogenic sources in winter is the major reason that caused theannually seasonal increasing rate from 1993 to 1997. The biogenic sources in Beijing are shrinking while the non-biogenic ones (such as fossil fuel combustion) are enlarging.  相似文献   

4.
Greenhouse gas(GHG) emissions from oil and gas systems are an important component of the GHG emission inventory. To assess the carbon emissions from oilfield-produced water under atmospheric conditions correctly, in situ detection and simulation experiments were developed to study the natural release of GHG into the atmosphere in the Shengli Oilfield,the second largest oilfield in China. The results showed that methane(CH4) and carbon dioxide(CO2) were the primary gases released naturally from the oilfield-produced water.The atmospheric temperature and release time played important roles in determining the CH4 and CO2emissions under atmospheric conditions. Higher temperatures enhanced the carbon emissions. The emissions of both CH4 and CO2from oilfield-produced water were highest at 27°C and lowest at 3°C. The bulk of CH4 and CO2was released from the oilfield-produced water during the first release period, 0–2 hr, for each temperature, with a maximum average emission rate of 0.415 g CH4/(m3·hr) and 3.934 g CO2/(m3·hr), respectively. Then the carbon emissions at other time periods gradually decreased with the extension of time. The higher solubility of CO2 in water than CH4 results in a higher emission rate of CH4 than CO2over the same release duration. The simulation proved that oilfield-produced water is one of the potential emission sources that should be given great attention in oil and gas systems.  相似文献   

5.
Atmospheric mixing ratios of carbonyl sulfide(COS) in Beijing were intensively measured from March 2011 to June 2013. COS mixing ratios exhibited distinct seasonal variation, with a maximum average value of 849 ± 477 pptv in winter and a minimal value of 372 ± 115 pptv in summer. The seasonal variation of COS was mainly ascribed to the combined effects of vegetation uptake and anthropogenic emissions. Two types of significant linear correlations(R2 0.66) were found between COS and CO during the periods from May to June and from October to March, with slopes(ΔCOS/ΔCO) of 0.72 and 0.14 pptv/ppbv, respectively. Based on the emission ratios of COS/CO from various sources, the dominant anthropogenic sources of COS in Beijing were found to be vehicle tire wear in summer and coal burning in winter. The total anthropogenic emission of COS in Beijing was roughly estimated as 0.53 ± 0.02 Gg/year based on the local CO emission inventory and the ΔCOS/ΔCO ratios.  相似文献   

6.
World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island(UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band 6 of two Landsat TM/ETM^ images of 1989 and 2000 to observe the UHI changes over l l-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen‘s urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index(URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu lsland. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and using light-colored, highly reflective roof and paving materials should be included in the plans of the city planers, environmental managers and other decision-makers to improve the overall urban environment in the future.  相似文献   

7.
The conversion rates of SO2 to SO42- and NO2 to HNO3+NO3- are estimated from the field-data obtained in Beijing in summer, 1988. The results show that the conversion rate of NO2 is about four times as much as that of SO2; The conversion rates have a diurnal variation in a day. On the average, the rate of SO2 is estimated to be 4.7% h-1 during the daytime and 3.4% h-1 during the nighttime. Similarly, the rate of NO2 is estimated to be 17.2% h-1 and 12% h-1 respectively.  相似文献   

8.
Observation of atmospheric nitrous acid with DOAS in Beijing, China   总被引:6,自引:0,他引:6  
Measurements of nitrous acid (HONO) and nitrogen dioxide (NO2) in Beijing City have been performed by means of a developed differential optical absorption spectroscopy (DOAS) system based on photodiode array (PDA), during the autumn of 2004. HONO and NO2 were simultaneously identified by their characteristic absorption bands in the spectral region between 337 nm and 372 nm with high sensibility and time resolution. The concentrations of HONO exhibit obviously diurnal variation with a nocturnal maximum and a daytime minimum. The highest HONO value up to 11.8 μg/m^3 was observed during the night of 2/3 September. Possible sources of the observed HONO were discussed. Good correlation to NO2 indicates that NO2 is a main source component. The measurement also shows direct emission of HONO is an imnortant source in strongly polluted urban area.  相似文献   

9.
As the biggest iron and steel producer in the world and one of the highest CO2 emission sectors, China’s iron and steel industry is undergoing a low-carbon transition accompanied by remarkable technological progress and investment adjustment, in response to the macroeconomic climate and policy intervention. Many drivers of the CO2 emissions of the iron and steel industry have been explored, but the relationships between CO2 abatement,investment and technological expenditure, and their connections with the economic growth and governmental policies in China, have not been conjointly and empirically examined. We proposed a concise conceptual model and an econometric model to investigate this crucial question. The results of regression, Granger causality test and impulse response analysis indicated that technological expenditure can significantly reduce CO2 emissions, and that investment expansion showed a negative impact on CO2 emission reduction. It was also argued with empirical evidence that a good economic situation favored CO2 abatement in China’s iron and steel industry, while achieving CO2 emission reduction in this industrial sector did not necessarily threaten economic growth.This shed light on the dispute over balancing emission cutting and economic growth.Regarding the policy aspects, the year 2000 was found to be an important turning point for policy evolution and the development of the iron and steel industry in China. The subsequent command and control policies had a significant, positive effect on CO2 abatement.  相似文献   

10.
Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic (reversed A^2O) and anaerobic/anoxic/aerobic (A^2O), were selected to investigate the emission characteristics of greenhouse gases (GHG), including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Results showed that although the processes were different, the units presenting high GHG emission fluxes were remarkably similar, namely the highest CO2 and N2O emission fluxes occurred in the aerobic areas, and the highest CH4 emission fluxes occurred in the grit tanks. The GHG emission amount of each unit can be calculated from its area and GHG emission flux. The calculation results revealed that the maximum emission amounts of CO2, CH4 and N2O in the three wastewater treatment processes appeared in the aerobic areas in all cases. Theoretically, CH4 should be produced in anaerobic conditions, rather than aerobic conditions. However, results in this study showed that the CH4 emission fluxes in the forepart of the aerobic area were distinctly higher than in the anaerobic area. The situation for N2O was similar to that of CH4: the N2O emission flux in the aerobic area was also higher than that in the anoxic area. Through analysis of the GHG mass balance, it was found that the flow of dissolved GHG in the wastewater treatment processes and aerators may be the main reason for this phenomenon. Based on the monitoring and calculation results, GHG emission factors for the three wastewater treatment processes were determined. The A^2O process had the highest CO2 emission factor of 319.3 g CO2/kg CODremoved, and the highest CH4 and N2O emission factors of 3.3 g CH4/kg CODremoved and 3.6 g N2O/kg TNremoved were observed in the Orbal oxidation ditch process.  相似文献   

11.
选取2015年8月至2016年9月杭州城区、远郊地区在线观测CO_2体积分数,分析杭州地区CO_2体积分数的城郊差异,并结合风向、CO_2体积分数周末效应、二十国集团(G20)峰会期间CO_2体积分数变化过程分析,探讨杭州城市对CO_2体积分数的影响程度.结果表明,杭州城区、远郊地区CO_2体积分数的日变化分布以单峰型形态为主,植物光合作用/呼吸作用和大气输送条件的日变化是主要的影响因素;城郊CO_2体积分数差值表现为双峰形态,人为排放对城郊CO_2体积分数差值的日变化分布存在重要影响.CO_2体积分数日变化幅度在春夏季节远郊地区大于城区,秋季则反之.杭州城区、远郊地区CO_2体积分数的季节变化趋势基本一致,均表现为冬、春季高,夏季低;城郊CO_2体积分数差值冬季最高,夏季最低.杭州地区CO_2体积分数高值的输送方向与周边城市区域的分布方向一致.杭州城区、远郊地区CO_2体积分数均呈现周末效应,尤其在城区,机动车排放对工作日-周末CO_2体积分数的日变化分布存在影响.杭州城区CO_2平均体积分数比远郊地区高9.3×10-6,G20峰会期间人为源排放的减少有效地降低了大气CO_2体积分数,尤其对市区的削减效果更为明显.  相似文献   

12.
杨乐  李贺鹏  孙滨峰  岳春雷 《环境科学》2017,38(12):5012-5019
新安江水库是我国华东地区最大的水库,面积580 km2,平均深度30 m,水库水体处于中贫营养状态.为了研究新安江水库中CO_2排放的时空变化特征,2014年12月至2015年12月采用静态浮箱法收集水库表面以分子扩散方式排放的CO_2,使用气相色谱仪分析CO_2浓度.结果表明,新安江水库CO_2排放通量从上游入库河流[(120.39±135.41)mg·(m~2·h)~(-1)]至库区主体[(36.65~61.94)mg·(m~2·h)~(-1)]呈下降趋势,而大坝下游河流中CO_2排放通量[(1 535.00±1 447.46)mg·(m~2·h)~(-1)]显著增加,约分别是上游入库河流和库区主体的13倍和25~42倍.但随着与大坝距离增加,大坝下游河流中CO_2排放通量显著下降,如7 km处的CO_2排放通量仅为出库水体处的20%.在库区主体中,CO_2排放通量具有明显的季节变化:CO_2排放通量在秋、冬季时为正值,最大值出现在冬季(12月或1月),说明此时库区表层水体是CO_2排放源;而CO_2排放通量在春、夏季为负值,最小值出现在春季(3、4或5月),说明此时库区表层水体是CO_2吸收汇,这可能与春、夏季时水体中藻类繁殖有关.所以,在调查水库表面CO_2排放时,应对水库的上游入库河流、库区主体和坝下河流进行全面长期的观测,才能避免低估水库中CO_2排放总量.  相似文献   

13.
中国城市建制及地理边界特征使得国际城市CO2排放的关键问题在中国难以深入研究.例如,城市排放占比,城市与周边区域排放差异等.本文基于天津市CO2排放的1 km网格,分析天津市CO2排放的空间特征,探讨天津市不同城市范围的CO2排放水平,并与纽约市进行对比分析.结果显示,2007年天津市市域内CO2排放总量为12599万吨,人均排放11.30 t.天津市市域CO2排放的空间格局是从中心6个城区向外单位网格排放量逐渐降低.CO2排放在空间上具有显著的正空间自相关性,中心6个城区、滨海新区及郊区县中心镇的CO2排放对其周边区域CO2排放影响显著,天津市狭义城市人均CO2排放量为4.71 t,低于纽约市的6.33t;狭义城市范围1排放占总排放的比例为69.26%,略高于纽约市的59.70%.以狭义城市为城市范围时,天津城市及周边区域人均CO2排放的空间特征与发达国家城市的排放特征研究结论一致,都是从城区—郊区—周边区域,人均排放水平逐渐升高;在此范围下,天津城市CO2排放仅占全市域的14.00%.  相似文献   

14.
红枫水库是我国西南喀斯特地区典型的人工湖泊,具有特殊的水文地质特征。准确估算其CO_2排放通量,对了解该水库碳循环具有重要意义。因此,于2017年7月至2018年4月采用走航式监测对库区(南湖和北湖)水气界面二氧化碳分压(pCO_2)和水质参数的时空变化进行了调查。结果表明,红枫水库pCO_2的分布具有明显的时空差异。库区秋、冬季表层水体pCO_2均超过大气pCO_2,表现为CO_2的净排放;春、夏季则相反,表现为CO_2的净吸收。从空间分布上来看,春、秋季北湖pCO_2要明显高于南湖,特别是秋季更为明显。另外,基于高频的走航监测数据,计算得到红枫水库全年CO_2的排放均值约为613mmol/(m~2·d)。  相似文献   

15.
通过分析2006年8月~2009年7月临安区域大气本底站Flask瓶采样获得的CO2浓度特征,结合碳追踪模式的模拟结果,研究了长三角地区碳源汇变化对CO2浓度的影响.结果表明,临安区域大气本底站的CO2浓度分布在368.3×10-6~414.8×10-6之间,具有较明显的季节波动变化特征,冬季高、夏季低,浓度年较差接近...  相似文献   

16.
基于城市汽车年检中CO2的过程动态检测数据,对小型汽油客车CO2的排放因子和排放水平信息进行了挖掘,并与文献研究结果进行了对比.结果表明,从城市汽车年检数据中挖掘的CO2排放结果可以作为研究城市机动车碳排放的重要参考依据;合理有效地利用汽车年检数据可以为城市车辆尾气排放的精准分级管控、城市交通运输碳排放达峰的量化分析,以及城市交通源的污染物和CO2协同减排提供重要的数据支撑;从国Ⅰ到国Ⅴ不同排放阶段汽油车的常规污染物CO、NOx和HC的排放水平下降非常明显,而对应的CO2排放水平差异不大;CO2排放因子随累计行驶里程、车龄、基准质量和排量的变化关系反映出,如果需要削减城市汽车碳排放水平,应鼓励使用基准质量小或者排量小的车辆,淘汰高油耗高排放的老旧车辆,鼓励公共绿色出行而降低单车活动水平,增加纯电动车辆优化车队能源结构.  相似文献   

17.
中国水泥工业CO2排放现状及减排对策   总被引:2,自引:0,他引:2       下载免费PDF全文
水泥工业是中国制造业中温室气体CO2的主要排放源,因此,根据水泥生产的基本原理和工艺特点,建立了CO2排放的数学模型并确定排放强度,计算了2001—2010年中国水泥工业CO2的排放量,分析了影响CO2排放量的主要因素及其发展趋势,并提出水泥工业CO2减排对策.结果表明,中国水泥工业CO2排放总量逐年增长,与水泥产量和单位产品原料、燃料消耗定额呈线性关系;在CO2排放总量中,原料煅烧和燃料燃烧阶段的排放量分别占49%和51%;"十一五"期间单位水泥产品CO2排放强度由0.69t.t-1下降到0.65t.t-1.万元GDPCO2排放量呈下降趋势,2008年达到最低值为0.3054t,平均每年万元GDPCO2排放量下降10.69%,说明水泥工业10年间实施节能降耗、资源循环利用、提高经济效益等措施对于减少CO2排放具有明显效果.  相似文献   

18.
利用IVE模型和对杭州市机动车排放管理数据库大数据的分析,得到杭州市2015年各类机动车主要温室气体高分辨率排放清单,分析了排放分担情况及时间变化特征,并利用Arc GIS及杭州市路网信息建立了1 km×1 km网格化空间分布.结果表明,杭州市道路移动源温室气体排放中CO_2、CH_4和N_2O的年排放量分别为818.11×10~4、0.85×10~4和0.07×10~4t,合计856.79×10~4t(以CO2当量计).从温室气体种类来看,CO_2占道路移动源温室气体排放总量的绝大部分,为95.5%;从机动车类型来看,小微型客车对道路移动源温室气体排放的贡献率最大,占72.8%;从道路类型的排放情况来看,杭州市市中心、城区、城郊和郊区中温室气体合计CO_2当量贡献率最高的均为主干路,分别为43.4%、61.8%、58.0%和42.4%.杭州市道路移动源温室气体排放强度均呈现由城市中心向城市边缘递减的趋势,同时温室气体排放量日变化特征明显,均出现弱双峰现象.  相似文献   

19.
城市是能源消耗的中心,电气化可以整合城市能源结构,实现清洁能源高效利用,探究城市低碳路径下加速电气化的协同减排影响对实现城市减污降碳至关重要.基于长期能源替代规划模型(LEAP-DG),设置了基准情景、低碳情景和加速电气化情景等3类情景,评估电气化措施在不同电力结构下的减排潜力,量化重点部门的措施贡献,探讨广东省典型制造业城市东莞的协同减排效果.结果表明,电力结构优化促进了电气化措施的协同减排效果,低碳路径下加速电气化将进一步降低电力污染物排放强度,2050年,东莞市CO2、 NOx、 VOC和CO减排7.35×106、 1.28×104、 1.62×104和8.13×104 t, SO2和PM2.5消费侧减排量和生产侧增排量达到平衡.电气化渗透速率和电力结构优化协调发展是电气化措施实现减排效益的关键,工业和交通部门加速电气化将同时降低CO2和大气污染物排放,交通部门得益于燃油车和电动车的高...  相似文献   

20.
基于2003-01~2005-06利用静态箱法对太湖水-气界面CO2交换通量的观测,对太湖水-气界面交换通量的变化特征进行了分析研究.结果表明:太湖水-气界面CO2交换通量存在明显的日变化,春、夏、秋、冬4季日平均通量分别为-0.79mg/(m2·h)、-4.89 mg/(m2·h)、-4.06 mg/(m2·h)和-2.56 mg/(m2·h),太湖均是CO2的汇.一般污染越重的区域,CO2通量值越大.藻型湖区水-气界面CO2交换通量季节变化不明显,草型湖区水-气界面CO2交换通量季节变化很明显,夏秋季高,冬春季低.CO2通量变化的可能相关因子还有天气情况、太阳辐射、风速及水温、pH、TA、Chla、TC、TN和TP等.  相似文献   

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