基于城市绿色生产性面积的生态补偿机制研究（英文）

我国城市扩张、粮食保障和能源转型形势严峻,如何挖掘城市建成环境的绿色生产潜力、探索一条通过粮食生产和太阳能利用节约土地空间并缓解生态压力的新途径？本文不同于以往生态补偿研究大多以重点生态功能区为对象或以财税补偿机制为手段,而是创新性地建立了一种城市空间内部的生态补偿机制。本文提出城市“绿色生产性面积”作为一种从城市生态学角度来衡量城市生态承载力提升潜力的方法,它基于将城市绿色资源收入换算成相同条件下它们所能节约的生态足迹面积。首先,通过类型学方法建立绿色生产补偿策略;其次,进行城市建成环境的全要素空间清查及其绿色生产潜力分析;最后,建立不同绿色生产的生态节地效益统一核算标准,并转换为绿色生产性土地面积指标。以天津市南开区学府街道为例,通过可利用的屋顶及闲置用地进行绿色生产,补充了该区12%的建筑所占用的自然土地所能提供的生态承载力。     

水质较好湖泊环境保护的理论基础及中国实践

目前,我国湖泊富营养化及蓝藻水华问题十分突出,国家高度重视湖泊的生态环境保护.自“九五”以来,国家就投入太湖、巢湖、滇池“老三湖”等重污染湖泊的治理,但成本巨大,且历经近30年才初见成效.按照湖泊污染程度,湖泊治理与保护可分为“污染治理型”“防治结合型”“生态保育型”3大类.“老三湖”的治理是典型的“先污染、后治理”的模式,水质较好湖泊主要属于生态保育型湖泊,因此,“老三湖”治理模式不适用于水质较好湖泊的保护.本文系统总结了我国水质较好湖泊优先保护理念的形成和水质较好湖泊专项实施的历程.根据水质较好湖泊的特点,及其生态系统退化与修复的一般过程,提出了水质较好湖泊保护的基本思路.从热力学角度,阐明了氮磷营养盐输入湖泊生态系统中是熵增过程,也是湖泊生态系统退化的根本原因,湖泊氮磷污染负荷源头控制是关键.湖泊流域生态安全格局是确保湖泊生态系统健康的基础,从景观生态学角度,阐明了优化湖泊流域水土资源利用、优化发展模式是减轻湖泊环境压力的重要途径.在浅水湖泊生态系统,以沉水植物占优势的“清水态”和以浮游植物占优势的“浊水态”转换过程不是沿着同一条途径,存在上临界阈值和下临界阈值,水生态修复过程表现出一种迟滞的现象.从湖泊水生态系统稳态转换理论角度,阐明了湖泊生态修复工程应在湖泊生态系统发生退化转变之前实施,才能获得较高的环境效益.通过国家财政专项对81个水质较好湖泊的支持,既能促进湖泊流域经济社会发展,又能确保湖泊水环境质量变好,湖泊水生态系统逐步改善.建议加强不同类型湖泊保护模式的总结,深入对水质较好湖泊生态系统演替理论和保护技术研究,支撑国家系统开展水质较好湖泊保护.     

2019年12月26日湖北应城M4.9地震震源参数及余震活动性研究

2019年12月26日湖北应城发生M4.9有感地震,其震感波及武汉大部分地区。为了分析该地震的发震构造及余震活动性,本文利用波形拟合方法测定了不同速度模型下该地震的震源机制解和矩心深度,并用Bootstrapping抽样反演技术评价反演结果;此外,利用模板匹配技术匹配主震和目录余震波形,获取了更为完整的余震目录。结果显示,应城地震以走滑为主,矩心深度7.5km左右,矩震级M_W4.67;应城地震有1个前震和17个余震,余震序列缺少M2~4事件,表明应城地震为孤立型地震,M2以下地震的b值为0.8。     

WRF模式三维变分中背景误差协方差估计

利用WRF模式2008年5-10月逐日预报结果,通过NMC方法进行背景误差协方差(B)估计.给出其结构特征,进行单点数值试验,并利用不同B进行1个月的数值模拟试验,检验模拟降水效果.结果表明:通过单点数值试验验证估算的B结构合理.不同的B,资料同化过程差别较大,应用重新统计的B,同化效率更高,目标函数收敛更稳定.模式模...     

Hydrological characteristics of karstic groundwater in the northeast Viet Nam as studied by isotopic techniques

The stable water isotopic composition (δ²H and δ¹⁸Ο), tritium (³H) activity, dissolved organic carbon, alkalinity, as well as the composition of carbon 13 (δ¹³C) in dissolved inorganic carbon (DIC) of 36 water samples taken from 16 resurgences in the northeast provinces of Viet Nam in the dry (Mar 2008) and rainy (June 2008) seasons were analyzed to elucidate hydrological characteristics of the karstic aquifers in the area. The stable water isotopic composition of the water samples collected clearly demonstrated that the karstic groundwater in the region was recharged from the local meteorological water. The tritium activity in the samples was found to be in between 3 and 4 TU, falling in the range of the ³H activity in the local precipitation and thus meaning that the traveling of recharge water to the resurgences was very short. Concentrated and diffuse allogenic recharges seem to be important sources of karstic groundwater in the study region. Water in the karstic aquifers could be classified into three types as: (a) water from karstic areas with dense vegetation cover that causes DIC be depleted in carbon 13 (¹³δ<?12‰ vs. Pee Dee Belemnite standard of Vienna, VPDB); (b) water from karstic areas with poor vegetation cover that originates DIC with carbon 13 composition ranging from ?11 to ?12‰; and (c) surface water from lakes, springs and rivers that has DIC with enriched carbon 13 (δ¹³C >?10‰). This implies that there are several sources of carbon dioxide contributing to the DIC in water of the karstic aquifers in the study region. Among other potential sources, the atmospheric CO₂, CO₂ from carbonate rock dissolution, biomineralization of soil organic matters and plant roots respiration seem to be important sources of the DIC in the waters of this region. The results show high vulnerability towards anthropogenic contaminants of karstic groundwater in the study region.     

Regional-scale surface air temperature and East Asian summer monsoon changes during the last millennium simulated by the FGOALS-gl climate system model

The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） model.The model was driven by both natural and anthropogenic forcing agents.Major features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 20th Century Warming （20CW）,were generally consistent with the reconstructions.The simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 20CW to be unprecedented over the last millennium in the simulation.The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation.The simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental regions.Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales.The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different reconstructions.The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south.Both the zonal and meridional thermal contrast were enhanced during the MCA.This temperature anomaly pattern favored a stronger monsoon circulation.     

双线偏振雷达测雨效果的对比分析

本文根据1993、1994年15次层状云和12次对流云降雨过程的地面降雨资料和C波段双线偏振雷达资料，对双线偏振雷达和普通雷达测量不同强度降雨的效果进行了评估和比较。结果表明，从相对误差来看，双线偏振雷达使普通雷达的小雨高估、大雨低估的测量误差趋势减弱，它对小到中雨的测量结果优于普通雷达。双线偏振雷达大雨高估的现象可能与强对流性降雨中冰相粒子的存在有关。     

2008年“7.02”滇中大暴雨的成因诊断与数值模拟

利用常规观测、NCEP 1°×1°再分析资料、云图、多普勒雷达回波和WRF模式对2008年7月2日滇中大暴雨进行成因诊断和数值模拟。结果表明:对流层高层的干侵入和中低层冷、暖平流交汇诱发副热带高压和滇缅高压间辐合低涡迅猛发展成强中尺度对流辐合体,加上中低层来自孟加拉湾的丰富水汽输送和中低层强水汽辐合共同引发此次大暴雨。过程中,垂直螺旋度贡献主要在中层;干位涡呈现出对流层顶强正高位涡,300 hPa以下为次正高位涡,两者之间为负区的柱状分布特征,次正高位涡强中心有向下层延伸特征。WRF较好地模拟了整个大暴雨过程中强降水主体时段和大暴雨落区特点,最大对流有效位能变化趋势对强降水有较好预示作用,模拟方案在积分30小时内效果较好。