“十三五”时期黄河流域PM2.5时空分布规律及多尺度社会经济影响机制分析     

耿佳辰  沈石  程昌秀 《地球信息科学学报》2022,24(6):1163-1175

黄河流域生态保护与高质量发展是我国新时代的重大战略任务。探究黄河流域PM_2.5浓度的时空变化趋势,并分析其社会经济影响因素,对该地区的大气污染防治和实现高质量发展具有重要意义。本文采用时间序列趋势估计、空间自相关分析、地理探测器和地理加权回归方法,揭示了“十三五”时期年黄河流域不同尺度（全流域以及61个地级市）PM_2.5浓度值和变化趋势的时空分异特征,定量探究了社会经济因素对PM_2.5浓度的影响机制及其时空过程。结果表明：① 在“十三五”时期,黄河流域的PM_2.5污染情况整体好转,其浓度呈波动下降的趋势,平均每年下降约4.2 μg/m³,彰显了我国大气污染防治攻坚战取得的重要成效;② 山东、河南、山西和陕西的PM_2.5浓度值较高,但山东、河南改善速度较快,山西和陕西改善速度较慢;③ 以目前的改善速率推算,在黄河流域61个地级市中,54个市将能够完成“十四五”规划中PM_2.5浓度下降10%的目标,而咸阳、西安、榆林、太原、临汾、运城、晋城7市将难以完成;④ 人口密度、工业企业数、土地利用强度是导致黄河流域PM_2.5浓度升高的主要社会经济因素,其解释力均达到50%以上;⑤ 从2015—2019年,土地利用程度指数和人口密度的主要影响区域均转移至黄河流域中部地区,建议山西、陕西、内蒙古应作为下一阶段治理工作关注的重点区域;⑥ 促进与环境承载力相协调的城乡发展、控制工业规模并提高其环保水平,是进一步治理黄河流域大气污染的重要策略。  相似文献   

春节人口迁移的气候效应:以郑州为例   总被引：1，自引：1，他引：0  

吴凌云  张井勇  远芳 《气候与环境研究》2016,21(1):41-46

目前,我们对人类活动通过温室气体、气溶胶和土地利用对气候产生重要影响已经获得了很多认识。但是,人口迁移流动在多大程度上能够影响气候尚不清楚。中国春节期间的人口大迁移是世界上每年最大规模的人类迁徙。利用城市站和参考站的气温差表示城市热岛强度,以一个典型中国中部大城市—郑州为例,研究了春节人口大迁移对城市热岛效应的影响。结果表明,2005~2013年平均的春节周日平均、日最高和日最低温度郑州站与中牟站的差分别为0.16°C、0.29°C和-0.03°C,比春节周前2~4周和春节周后2~4周的平均值低了0.50°C、0.06°C和0.66°C。相对变化而言,日平均、日最高和日最低温度的差分别降低了76%、16%和105%。春节周日平均和日最低温度的差的变化都通过了99%的信度检验。  相似文献   

The Meteors, Meteoroids and Interplanetary Dust Program of the International Heliophysical Year 2007/9     

Svitlana V. Kolomiyets  Mykola I. Slipchenko 《Earth, Moon, and Planets》2008,102(1-4):305-307

Under the title ‘Meteors, Meteoroids and Interplanetary Dust’, meteor research is included in the program of the International Heliophysical Year 2007/9.We list issues for coordinated meteor research within the framework of this global international program.  相似文献   

Variability of phytoplankton biomass in a lowland river: Response to climate conditions   总被引：2，自引：0，他引：2  

Blanka Desortová  Pavel Pun?ochá? 《Limnologica》2011,41(3):160-166

The results are presented of an intensive study of phytoplankton assemblage carried out in the Berounka River above its confluence with the Vltava River (Czech Republic) in the period 2002–2007. The annual and interannual changes of phytoplankton development (based on high frequency of sampling) and their relation to hydrological conditions and concentrations of main nutrients are analysed. A marked decline of nutrient concentrations was observed during the period 1996–2007. The annual mean values of total P decreased from 0.43 mg L⁻¹ to 0.16 mg L⁻¹, those of N-NO₃ from 4.6 mg L⁻¹ to 1.5 mg L⁻¹ and N-NH₄ from 1.9 mg L⁻¹ to 0.04 mg L⁻¹. Despite this, the phytoplankton biomass remained at a high level. The seasonal mean values of chlorophyll-a ranged from 51.0 μg L⁻¹ to 116.8 μg L⁻¹ in the same time period. An obviously stronger relationship was found of the phytoplankton biomass and pattern of its development to the variation of flow rates than to the existing level of nutrient concentrations. A significantly decreasing relationship (R² = 0.384, P < 0.001) of chlorophyll-a to flow rates and a significantly increasing relationship (R² = 0.359, P < 0.001) of chlorophyll-a to water temperatures were found, based on monthly mean values for the seasonal period 2002–2007. The results obtained indicate a remarkable increase of phytoplankton biomass and its prolongated occurrence in watercourses, which can be expected due to the consequences of the predicted climate change (i.e. higher occurrence of summer droughts and low precipitation amounts accompanied by a substantial drop of flow rates, increase of air and water temperatures), as described in the respective scenarios for the territory of the Czech Republic. Simulations by the regional climate models HIRHAM and RCAO and emission scenario SRES indicated the increase of air temperature by 2.5–5 °C, decrease of precipitation amount by 6–25% and decline of flows by 14–43% in the Berounka River for the scenario period 2071–2100.  相似文献   

“十二五”规划编制若干问题的探讨     

秦龙杰 《中国勘察设计》2011,(2):49-52

针对"十二五"发展规划编制的新要求,结合多年规划编制经验,提出新时期规划编制特点、作用和主要方法,指导规划编制工作。  相似文献   

Self-consistent neutrino and UHE cosmic ray spectra from Mrk 421     

《Astroparticle Physics》2014

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窄线Seyfert 1型星系研究的新进展     

程林鹏  赵永恒 《天文学进展》2002,20(3):282-294

窄线Seyfert1型星系（NLS1）作为活动星系核的一个小类，由于其X射线等高能波段上独特的观测特征，近年来越来越受到天文学界的广泛关注，详细描述了NLS1在观测及理论上的一些新进展，并对其主要模型作了较细致的讨论。  相似文献   

Distribution of SiO and OH Maser Stars in the Galactic Plane     

Bi－WeiJiang  Shu－MeiJia 《中国天文和天体物理学报》2001,1(2):144-151

The observational results of the Nobeyama 45-m SiO maser survey and the Arecibo 305-m OH maser survey are assembled for an analysis of the distribution and kinematics of late-type stars in the Galactic plane.It is found that neither SiO maser stars nor OH maser stars show any concentration to the spiral arms,which imply that they do not belong to the arm population and quite possibly they are low-mass stars in late stage of evolution.A rotational curve is also derived for these objects and a few features which may be real are discussed and compared with those derived from planetary nebulae and AGB stars.  相似文献   

银道面上下的奇对称环向磁场     

韩金林 《中国天文和天体物理学报》1996,(4)

在分析河外射电源和脉冲星的法拉弟旋度（RotationMeasure，RM）时，发现银道面上下有规则的奇对称环向磁场分量，这是任何银盘磁场模型所无法解释的．这种奇对称的环向磁场说明在银冕中运行着AO模式的Dynamo。  相似文献   

银心的观测与研究     

傅承启  侯金良  常瑞香 《天文学进展》2004,22(2):134-151

银心是离我们最近的星系核，它属于活动低下的典型星系核，对它的研究不仅是银河系结构研究中不可缺少的一环，而且是研究黑洞和活动星系核的极好样本。简要回顾了近10年对银心观测和研究的主要结果，并对银心的基本构造和组成，特别是对射电源SgrA及其银心暗天体的性质和模型作了比较全面的概括和总结。  相似文献