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1.
城市空气质量GIS数据模型及分析系统的集成与应用   总被引:4,自引:0,他引:4  
城市空气质量模拟是目前环境与健康研究的一个重要领域。本文基于GIS技术,采用准稳态高斯扩散模型建立了城市空气质量模拟系统,着重研究了三维空间城市空气质量模型系统的集成方法,并以福州市为例,采用该模型系统对城市建城区的NO2与SO2年平均浓度场分布进行了模拟。  相似文献   

2.
PM2.5是威胁人体健康的主要大气污染物之一。大量研究关注近地面PM2.5浓度的监测及其时空分布,但目前针对PM2.5排放及其与近地面浓度之间的关联研究较为缺乏。本文通过2000—2014年近地面PM2.5浓度格网数据和PM2.5排放格网数据,采用长时间序列分析法对PM2.5浓度和PM2.5排放从定性和定量两个角度进行时空变化趋势对比研究,并进一步结合标准差椭圆法和趋势分析法,分析了我国近地面PM2.5浓度和PM2.5排放的时空变化特征及其关联。结果表明,从总体时间序列趋势上,近地面PM2.5浓度和PM2.5排放之间在空间分布上基本呈现一致性,集中在胡焕庸线以东的人口密集区,但在时间上,PM2.5浓度和排放之间存在动态变化时间差。且PM2.5浓度的变化更为明显,2000—2007年高于35 μg/m3的国土面积占比增加了14.26%,2007—2014年减少了2.84%;从标准差椭圆分析来看,PM2.5浓度椭圆和排放椭圆在覆盖面积和方位角上与人口和经济分布吻合,但前者面积更大,长轴更接近于东西方向,二者存在约17°差异,而两类椭圆的中心位置随时间变化呈现出较一致的轨迹特征并呈现出滞后特点;此外,受大气扩散、点源排放等因素影响,PM2.5浓度变化趋势与排放变化趋势在胡焕庸线以东并不完全一致,部分区域排放呈降低趋势而浓度则反而呈升高趋势。因此,从全国层面来看,减排政策对浓度降低在时间上虽存在滞后,但边际效益显著,并已显露成效;而从局地来看,受地形、气象条件和大气化学过程等复杂影响,二者的变化在空间上仍会存在差异,有待进一步深入研究;从防控措施来看,在继续加强落实本地减排政策的同时,应考虑污染物的扩散迁移规律,加强联防联控,有效改善空气质量。  相似文献   

3.
The response of the North Pacific Subtropical Mode Water and Subtropical Countercurrent (STCC) to changes in greenhouse gas (GHG) and aerosol is investigated based on the 20th-century historical and single-forcing simulations with the Geophysical Fluid Dynamics Laboratory Climate Model version 3 (GFDL CM3). The aerosol effect causes sea surface temperature (SST) to decrease in the mid-latitude North Pacific, especially in the Kuroshio Extension region, during the past five decades (1950–2005), and this cooling effect exceeds the warming effect by the GHG increase. The STCC response to the GHG and aerosol forcing are opposite. In the GHG (aerosol) forcing run, the STCC decelerates (accelerates) due to the decreased (increased) mode waters in the North Pacific, resulting from a weaker (stronger) front in the mixed layer depth and decreased (increased) subduction in the mode water formation region. The aerosol effect on the SST, mode waters and STCC more than offsets the GHG effect. The response of SST in a zonal band around 40°N and the STCC to the combined forcing in the historical simulation is similar to the response to the aerosol forcing.  相似文献   

4.
High PM2.5 concentrations and frequent air pollution episodes during late autumn and winter in Jilin Province have attracted attention in recent years. To describe the spatial and temporal variations of PM2.5 concentrations and identify the decisive influencing factors, a large amount of continuous daily PM2.5 concentration data collected from 33 monitoring stations over 2-year period from 2015 to 2016 were analyzed. Meanwhile, the relationships were investigated between PM2.5 concentrations and the land cover, socioeconomic and meteorological factors from the macroscopic perspective using multiple linear regressions (MLR) approach. PM2.5 concentrations across Jilin Province averaged 49 μg/m3, nearly 1.5 times of the Chinese annual average standard, and exhibited seasonal patterns with generally higher levels during late autumn and over the long winter than the other seasons. Jilin Province could be divided into three kinds of sub-regions according to 2-year average PM2.5 concentration of each city. Most of the spatial variation in PM2.5 levels could be explained by forest land area, cultivated land area, urban greening rate, coal consumption and soot emissions of cement manufacturing. In addition, daily PM2.5 concentrations had negative correlation with daily precipitation and positive correlation with air pressure for each city, and the spread and dilution effect of wind speed on PM2.5 was more obvious at mountainous area in Jilin Province. These results indicated that coal consumption, cement manufacturing and straw burning were the most important emission sources for the high PM2.5 levels, while afforestation and urban greening could mitigate particulate air pollution. Meanwhile, the individual meteorological factors such as precipitation, air pressure, wind speed and temperature could influence local PM2.5 concentration indirectly.  相似文献   

5.
The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportation have contributed to climate change and environmental degradation. Scientifically, analysts still have controversies regarding how to calculate the emissions and how to choose the baseline and methodologies. Three methods are generally used, namely the ‘bottom up’ approach, the ‘top down’ ap...  相似文献   

6.
风险分析与评估是解决边坡固有不确定性的重要工具, 但同时考虑外在荷载和内在岩土力学参数的不确定性, 对边坡进行系统定量风险分析的研究较少。以西藏扎拉水电站厂后倾倒变形边坡为例, 基于场地地震峰值加速度概率密度函数和不同地震峰值加速度下边坡失稳概率拟合函数, 采用数值积分计算了边坡在设计基准期的失稳概率, 并采用离散元方法对边坡失稳后的影响范围进行了数值模拟, 在此基础上进行了承灾体易损性分析及定量风险计算, 最后采用ALARP准则进行了风险评价。研究表明, 考虑地震危险性条件下, 扎拉水电站厂后倾倒变形边坡在50 a设计基准期内失稳概率为0.061 9;边坡对水电站地面厂房存在较大威胁, 相应财产风险为5 482万元; 根据ALARP准则, 边坡风险处于不可接受区, 需采取措施防范或规避风险。研究成果对于边坡治理工程决策及风险管理具有指导意义。   相似文献   

7.
一种改进的基于TIN渐次加密的LiDAR点云滤波算法   总被引:1,自引:0,他引:1  
在深入研究原始不规则三角网(Triangulated Irregular Network,简称TIN)算法的基础上,提出了一种改进的TIN算法。该改进算法通过构建网格筛选地面种子点来提高初始面的可信度。在向上加密过程的四面体顶点阈值选取上,采用了基于局部地形坡度的自适应阈值,克服了原始算法预先设定单一阈值的局限性。实验结果表明,该改进算法可以有效降低三类误差,其中,I类误差降幅达50%,II类误差达30%,总误差达40%。  相似文献   

8.
This paper constructed a carbon emission identity based on five factors: industrial activity, industrial structure, energy intensity, energy mix and carbon emission parameter, and analyzed manufacturing carbon emission trends in Jilin Province at subdivided industrial level through Log-Mean Divisia Index(LMDI) method. Results showed that manufacturing carbon emissions of Jilin Province increased 1.304 × 107 t by 66% between 2004 and 2010. However, 2012 was a remarkable year in which carbon emissions decreased compared with 2011, the first fall since 2004. Industrial activity was the most important factor for the increase of carbon emissions, while energy intensity had the greatest impact on inhibiting carbon emission growth. Despite the impact of industrial structure on carbon emissions fluctuated, its overall trend inhibited carbon emission growth. Further, influences of industrial structure became gradually stronger and surpassed energy intensity in the period 2009–2010. These results conclude that reducing energy intensity is still the main way for carbon emission reduction in Jilin Province, but industrial structure can not be ignored and it has great potential. Based on the analyses, the way of manufacturing industrial structure adjustment for Jilin Province is put forward.  相似文献   

9.
海南岛独特的区域和国家战略位置,使得了解和掌握该地区气溶胶时空格局特征及其大气污染物传输来源是海南大气环境质量监测和污染防治中重要的关注问题。选取MODIS 3 km分辨率气溶胶光学厚度(AOD)产品MOD04_3K,对海南岛2003—2017年AOD时空变化特征进行分析;以海口市为起始点,采用HYSPLIT模式对8次典型大气污染事件在10、500、1000 m 3个相对地面高度上进行48 h后向轨迹计算,以探究该区域大气污染物来源。结果表明:① 海南岛AOD在空间上呈较为明显的三级阶梯状分布,从西北方向向东南递减,2003—2017年在不同阶梯的空间变化趋势差异十分显著;② 2003—2017年海南岛AOD年均值为0.095,各年均值整体呈轻微升高趋势;季节均值差异表现为“春季>秋季>冬季>夏季”,此差异除受区域天气系统与地方风向特征的影响外,本区旅游业发展造成的大气污染物排放也不可忽视;③ 海南岛(海口市)2013—2017年典型大气污染事件发生期间大气污染气流在3个高度上(10、500、1000 m)的后向轨迹基本保持一致,均主要来自于海南岛东北方向。据此,位于该方向毗邻的珠江三角洲地区陆源大气污染物在东北盛行风的影响下被输送至海南岛,在区域天气系统(如大陆冷高压)和局部天气系统(如海风辐合)共同作用下,是促成该地区大气污染事件发生的重要因素。研究结果对深入理解海南岛近十多年来大气环境状况的变化规律、完善该区域大气污染联防联控机制具有重要的意义。  相似文献   

10.
Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine meadow at three elevations(4313 m, 4513 m and 4693 m) in Northern Tibet to test the hypothesis that clipping would alter warming effect on biomass production.Open top chambers(OTCs) were used to increase temperature since July,2008 and the OTCs increased air temperature by approximately 0.9o C ~ 1.8o C during the growing in2012.Clipping was conducted three times one year during growing season and the aboveground parts of all live plants were clipped to approximately 0.01 m in height using scissors since 2009.Gross primary production(GPP) was calculated from the Moderate-Resolution Imaging Spectroradiometer GPP algorithm and aboveground plant production was estimated using the surface-measured normalized difference vegetation index in 2012.Warming decreased the GPP, aboveground biomass(AGB) and aboveground net primary production(ANPP) at all three elevations when clipping was not applied.In contrast, warming increased AGB at all three elevations, GPP at the two lower elevations and ANPP at the two higher elevations when clipping was applied.These findings show that clipping reduced the negative effect of warming on GPP, AGB and ANPP, suggesting that clipping may reduce the effect of climate warming on GPP, AGB and ANPP in alpine meadows on the Tibetan Plateau, and therefore, may be a viable strategy for mitigating the effects of climate change on grazing and animal husbandry on the Tibetan Plateau.  相似文献   

11.
为实现“一带一路”区域可持续发展,我国倡导绿色、低碳、循环、可持续的生产生活方式,建设绿色“一带一路”。遥感技术在生态环境监测与评价方面具有重要作用。本文以“一带一路”区域中国援建的水电站工程为研究对象,基于陆地系列卫星(Landsat)、哨兵2号(Sentinel-2)等遥感对地观测数据,利用决策树与缓冲区分析等方法,从水电站库区概况、水电站对植被生长状况与生态资源影响等方面,开展“一带一路”区域水电站项目建设对当地经济发展和生态环境影响的遥感监测及分析。本文首先根据遥感影像与DEM确定库区及库容,结合最小外接正方形面积比及平均宽度等指标确定各水电站缓冲区类型和范围。利用NDWI及NDVI构建决策树模型,提取各缓冲区土地利用类型,分为水体、林地、草地、耕地和其它5类;结合区域植被覆盖度,估算库区生态占用并对水电站建成前后的土地利用类型和植被变化进行分析。研究结果表明:① “一带一路”沿线10座水电站造成的生态损失与库区面积呈正相关,不同工程间,在水体、林地、草地、耕地和其它方面的损失面积大小存在较大差异;② 土地利用类型与植被覆盖度年均变化幅度约为0.35%、1.27%,水电站修建对周边生态资源与植被生长状况影响较小,同时在植被覆盖度较低的地区水电站的修建会明显改善周边环境;③ 各水电站周边的植被覆盖度差异较大,大部分水电站周边植被生长状况良好;④ 水电站建设始终坚持工程建设与环境保护并重,从施工设计到水电站后期维护期间,积极采取环保措施,减少占用,保护生物多样性,生态风险防范得当;⑤ 水电站提供了优质的清洁能源,促进了当地经济和社会发展。  相似文献   

12.
Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that in the lower troposphere the meridional wind speed and mean annual wind speed decrease, and in the lower stratosphere the temperature decreases while the meridional wind speed increases significantly. In the study area, the climate is becoming warmer and wetter in the middle lower troposphere. The expansion of urban area has great effects on the surface air temperature and the wind speed, leading to the increase of the surface air temperature, the decrease of the surface wind speed, and the increase of the area of urban high temperature zone. The quantitative equations have been established among the surface air temperature, the carbon dioxide (CO2) concentration and the specific humidity (the water vapor content). It is predicted that the future increasing rate of the surface air temperature is 0.85°C/10yr if emission concentration of CO2 remains unchanged; if emission concentration of CO2 decreases to 75%, 50% and 25%, respectively, the surface air temperature will increase 0.65°C/10yr, 0.46°C/10yr and 0.27°C/10yr, respectively. The rise of the surface air temperature in the study area is higher than that of the global mean temperature forecasted by IPCC.  相似文献   

13.
The hallmark of development in the Yangtze River Delta (YRD) of East China has been sprawling urbanization. However, air pollution is a significant problem in these urban areas. In this paper, we investigated and analyzed the air pollution index (API) in four cities (Shanghai, Nanjing, Hangzhou and Ningbo) in the YRD from 2001 to 2012. We attempted to empirically examine the relationship between meteorological factors and air quality in the urban areas of the YRD. According to the monitoring data, the API in Shanghai, Nanjing, Hangzhou slightly declined and that in Ningbo increased over the study period. We analyzed the inter-annual, seasonal, and monthly variations of API, from which we found that the air quality had different temporal changes in the four cities. It was indicated that air quality was poor in winter and spring and best in summer. Furthermore, different weather conditions affected air quality level. The wind direction was considered as an important and influential factor to air pollution, which has an impact on the accumulating or cleaning processes of pollutants. The air quality was influenced by the different wind directions that varied with seasons and cities.  相似文献   

14.
Hydrogen and oxygen isotopes in precipitation have been widely used as effective traces to investigate hydrological processes such as evaporation and atmospheric moisture source. This study analyzed δD and δ~(18)O of precipitation in continuous event-based samples at three stations of Pailugou Catchment from November 2012 to December 2013. The δ~(18)O and δD values ranged from-32.32‰ to +3.23‰ and from-254.46‰ to +12.11‰, respectively. Results show that the δ~(18)O displayed a distinct seasonal variation, with enriched values occurring in summer and relatively depleted values in winter, respectively. There was a statistically significant positive correlation between the δ~(18)O and δD values and local surface air temperature at all the three stations. The nearest Global Network of Isotopes in Precipitation(GNIP) station(Zhangye), compared to the Meteoric Water Lines for this study, showed the obvious local evaporation effects with lower intercept and slope. Additionally, d-excess(δD- 8δ~(18)O) parameter in precipitation exhibited an anti-phase seasonal variability with the δ~(18)O. The 96-h back trajectories for each precipitation event using Hybrid Single Particle Lagrangian Integrated Trajectory(HYSPLIT) model indicated a dominant effect of westerly air masses in summer and the integrated influence of westerly and polar air masses in winter.  相似文献   

15.
This study analyzed the spatio-temporal variability of air quality data for six standard air pollutants(Particulate Matter 2.5(PM_(2.5)), Particulate Matter 10(PM_(10)), SO_2, NO_2, CO, and O_3) in the Sichuan Basin(SCB), China from 2015 to 2018 in relation to the formation of haze using conventional meteorological data(temperature, wind speed, and relative humidity), satellite data(fire point data, vertical profiles of aerosol subtypes, and aerosol optical depth), planetary boundary layer height, and backward trajectories. The results indicated that the spatio-temporal evolution of the air quality index(AQI) had notable seasonality for the pollution severity in descending order: winter, spring, summer, and autumn. Autumn and winter severe haze events occurred in November and January, respectively, and were caused by higher local pollution emissions under stagnant air conditions. Spring severe haze events occurred in May and were caused by dust from Northwest China and local regions. Severe summer haze events occurred in July and were caused by local burning. Therefore, the analyses showed that local burning, stagnant meteorological conditions, air mass transport and anthropogenic pollution emissions played a key role in haze in the SCB. This study provides scientific insights for fully analyzing heavy air pollution in SCB, China, and also provides a scientific basis for pollution research in regions of complex terrain as basins and mountains.  相似文献   

16.
1990~2000年中国稻田甲烷排放变化模拟   总被引:3,自引:0,他引:3  
甲烷(CH4)是大气中重要的温室气体之一。研究我国稻田的甲烷排放年际变化,客观评估我国稻田CH4排放量,对于区域乃至全球大气CH4浓度的贡献具有积极意义。本文将一个比较成熟的稻田甲烷排放模型CH4MOD和G IS空间化数据库结合,模拟估计了中国大陆1990~2000年水稻生长季稻田甲烷排放的年际变化。模拟结果表明:从1990年到2000年,我国稻田甲烷排放量具有比较明显的年际波动,其中1993~1995年由于播种面积较少,甲烷排放为一个低谷,排放量约为5.37Tg;其他年份的排放量在5.93~6.22Tg之间。虽然1997年之后我国水稻播种面积比1993年之前少约1.84×106hm2,但两个时期的甲烷排放量却基本相等,这主要是由于1997年之后单位面积稻田甲烷的排放也较1993年之前高的缘故。从空间格局方面讲,我国稻田甲烷排放的高值区主要分布在湖南、湖北、江西、广东、广西、四川、江苏和安徽,东北地区稻田甲烷排放在20世纪90年代有逐年增加的趋势。  相似文献   

17.
新型格网DEM等高线生成技术与方法   总被引:1,自引:0,他引:1  
以格网DEM数据为基础,生成具有良好保凸性、光滑性、平顺性特征的高质量等高线,已逐渐成为制作等高线图的重点。鉴于现有技术方法在沟道、山脊等地形变化部位生成的等高线中存在生硬、相交、异常闭合等问题,本文以黄土丘陵1:5万不同格网分辨率DEM为例,采用对比分析方法,建立了基于DEM格网加密技术的高质量等高线生成方法。实验表明:(1)采用以4×4 DEM格网单元为搜索圆的完全规则样条函数插值法,以可视化时图面0.1 mm的实际距离为加密DEM的格网分辨率值,对DEM格网进行加密处理后生成的等高线具有更为理想的保凸性、光滑性和平顺性特征;(2)对于已知综合尺度的地形,存在最优DEM格网分辨率阈值,若要高质量地再现原始等高线,则实际DEM格网分辨率不得低于最优DEM格网分辨率阈值。  相似文献   

18.
Based on the finite-volume coastal ocean model(FVCOM),a three-dimensional numerical model FVCOM was built to simulate the ocean dynamics in pre-dam and post-dam conditions in Bachimen(BCM).The domain decomposition method,which is effective in describing the conservation of volume and non-conservation of mechanical energy in the utilization of tidal energy,was employed to estimate the theoretical tidal energy resources and developable energy resources,and to analyze the hydrodynamic effect of the tidal power station.This innovative approach has the advantage of linking physical oceanography with engineering problems.The results indicate that the theoretical annual tidal energy resources is about 2×10~8 k Wh under the influence of tidal power station;Optimized power installation is confirmed according to power generation curve from numerical analysis;the developable resources is about 38.2% of theoretical tidal energy resources with the employment of one-way electricity generation.The electricity generation time and power are 3479 hours and 2.55×10~4 KW,respectively.The power station has no effect on the tide pattern which is semi-diurnal tide in both two conditions,but the amplitudes of main constituents apparently decrease in the area near the dam,with the M_2 decreasing the most,about 62.92 cm.The tidal prism shrinks to 2.28×10~7 m~3,but can still meet the flow requirement for tidal power generation.The existence of station increases the flow rate along the waterway and enhances the residual current.There are two opposite vortexes formed on the east side beside the dam of the station,which leads to pollutants gathering.  相似文献   

19.
Mountain ecosystem,on the earth,has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade. However,every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya,it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards,such as landslides,rock fall and soil erosion,have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study,therefore,focuses mainly on the Parbati Stage Ⅱ (800 MW) and the Parbati Stage Ⅲ (520 MW) hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities,the existing land use pattern,status of total acquired land of the residents by hydropower projects,frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage Ⅱ and Ⅲ have been analysed in the paper. Also,the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.  相似文献   

20.
Crop residue incorporation has been widely accepted as a way to increase soil carbon (C) sequestration and sustain soil fertility in agroecosystems. However, effect of crop residue incorporation on greenhouse gas (GHG) emissions in rice paddy soils remains uncertain. A field experiment was conducted to quantify emissions of CH4 and N2O and soil heterotrophic respiration (RH) from a paddy rice field under five different crop residue treatments (i.e., 150 kg N ha-1 of synthetic N fertilizer application only [NF], 150 kg N ha-1 of synthetic N fertilizer plus 5.3 Mg ha-1 wheat residue [NF-WR1], 150 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [NF-WR2], 75 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [50%NF-WR2] and 150 kg N ha-1 of synthetic N fertilizer plus 21.2 Mg ha-1 wheat residue [NF-WR3]) in southwest China. Our results showed that crop residue incorporation treatments (NF-WR1, NF-WR2, 50%NF-WR2, NF-WR3) significantly increased CH4 emissions by at least 60%, but N2O emissions were not enhanced and even suppressed by 25% in the NF-WR3 treatment as compared to the NF treatment. Soil RH emissions were comparable among experimental treatments, while crop residue incorporation treatments significantly increased soil carbon sequestrations relative to the NF treatment. Overall, CH4 emissions dominated total global warming potentials (GWP) across all experimental treatments. The average yieldscaled GWPs for the NF and NF-WR1 treatments were significantly lower than for the NF-WR2, 50%NFWR2 and NF-WR3 treatments. Given the comparable yield-scaled GWPs between the NF and NF-WR1 treatments, the NF-WR1 treatment could gain net carbon sequestration as compared with the NF treatment with net soil carbon loss. Our findings suggest that the NF-WR1 treatment should be an effective option to sustain rice production while mitigating GHG emissions from the rice field in China.  相似文献   

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