近六百年来长江三角洲地区城镇空间与城镇体系格局演变分析

基于历史文献、古地图和现代遥感数据,引入历史学古代城镇形态复原方法,复原（提取）明代以来长江三角洲地区113座城镇7个时间断面（1461年、1820年、1930年、1970年、1980年、2000年和2010年）下的城镇边界,采用扩张速率、扩张效率、首位度指数和位序-规模法则,分析了近六百年来区域城镇空间与城镇体系等级规模演变格局。取得以下研究结果：\mathrm{①}研究时段内,区内城镇用地总规模由205.98 km²增加到6442.19 km²,扩大了31.27倍;城镇扩张经历了萌芽阶段（明清时期）、起步阶段（民国至改革开放前夕）、成长阶段（改革开放至2000年）和加速阶段（2000—2010年）,城镇扩张速率不断加快,但扩张效率有待提升;\mathrm{②}在城镇等级规模空间格局上,明清时期南京与苏州为区内的一级城镇,民国后,上海逐渐取代其地位,从五级城镇发展成为区域核心城镇,四级以上城镇主要集中在长江干流沿岸和太湖流域,五级以下城镇大多集中在安徽;城镇体系呈首位型分布,城镇首位度较高,且改革开放后的城镇首位度较明清与民国时期要高,不同等级规模城镇之间差距扩大,大城镇优势较强。近30年,长江沿岸城镇发展加速,苏锡常都市圈、南京都市圈等逐渐形成并快速发展。     

国土空间规划中城镇空间和城镇开发边界的划定

在2016年国务院印发的《省级空间规划试点方案》所提出的“开展基础评价”和“绘制规划底图”两项主要任务中,城镇适宜性的评价与城镇空间、城镇开发边界的划定属于核心内容,同时也是一项具有较强探索性的工作。以国家对国土空间规划的基本设想为依据,对城镇空间和城镇开发边界的概念和内涵、空间关系、相关规则进行深入探讨,确定了城镇适宜性评价与城镇空间、城镇开发边界划定的主要思路和技术路线。结合福建省空间规划的案例,分析了城镇适宜性评价与城镇空间、城镇开发边界划定的过程、方法和结果。不同于以往各部门开展的空间性规划,城镇空间和城镇开发边界的划定建立在资源环境承载能力和国土空间开发适宜性的基础评价之上,这使得城镇开发建设活动的空间布局在资源环境本底方面得到合理保障,城镇空间和城镇开发边界的划定也有了较为科学、客观的依据。此外,把基础底图的研制与城镇发展潜能、城镇开发指向的评估,以及开发建设的规模管控、空间管控、开发强度管控系统地整合起来,使得规划底图的随意性得到了较好的控制。实践表明,本文的思路和技术方法是合理可行的,这一尝试可为空间规划理论和方法体系的完善提供参考。     

基于耗散结构系统熵模型的乡村生产空间系统有序性研究

通过分析乡村生产空间系统的耗散结构特征,建立系统熵模型,运用关联熵和运行熵,从系统的主体（多元主体）、客体（地）和环境三要素入手构建指标体系,讨论系统内部结构和运行状态的有序性,并以重庆市合川区龙市镇为研究区予以实证,研究表明：研究区乡村生产空间系统关联熵先增后减,系统内部结构有序性呈现阶段性特征,2008—2011年主要受城市化无序扩张和土地利用方式低效粗放等因素影响,系统内部结构趋于混乱无序,2011—2015年主要因财政支农力度增强、农业投入产出水平提高、生态修复力度加大等因素刺激,系统内部结构逐渐趋于有序化;2008—2015年,乡村生产空间系统运行熵逐年减小,在农业综合开发投入大幅增加引起的生产条件改善、产业结构调整与提档升级等驱动下,呈现出持续有序化的发展态势;围绕乡村生产空间系统的内部结构及运行状态的演化规律,从优化土地利用结构、构建现代农业产业体系、编制和完善相关规划、培育新产业新业态入手,提出相关策略,以促进乡村生产空间系统有序健康发展。     

城市精明发展与生态效率的协同测度及交互响应——以中国276个地级以上城市为例

城市发展与生态环境存在复杂的动态交互耦合过程,厘清精明发展与生态效率的协同发展关系及交互响应机理,是区域可持续发展的关键环节。本文以2003—2015年中国276个地级以上城市为研究对象,采用多指标综合评价法、Super-SBM模型、灰色关联模型和面板VAR模型对中国城市精明发展与生态效率的协同发展和交互响应关系进行综合测度。研究表明：① 城市精明发展呈现从沿海向内陆阶梯递减的空间演变趋势,多个城市群具有较高的城市精明发展指数。② 生态效率与精明发展的空间变化具有一定的耦合特征,沿海地区南北方向呈现出较高水平的“生态弧线”城市带。③ 城市精明发展与生态效率具有显著的关联性特征,协同发展关系有下降趋势。④ 城市精明发展与生态效率存在双向交互的Granger因果关系,具有正向的交互响应关系,且存在一定的路径依赖特征和惯性发展趋势。⑤ 长期而言,城市精明发展对生态效率变动的影响更大。     

不同空间尺度的山洪灾害风险评价模型对比研究

以山洪灾害风险评价的多准则决策模型、最大熵模型、信息量模型三种常见模型为研究对象,选取河西走廊和张掖市为地理区划（大中）、市域（小）空间尺度研究区,构建山洪灾害风险评价指标体系,分别完成基于三种模型的两种空间尺度的山洪灾害风险评价制图,基于甘肃省地质灾害调查与区划报告数据从模型验证、空间自相关、精度对比和尺度效应等角度对比分析三个模型应用于不同空间尺度的适应性,并给出优选模型。结果表明：最大熵模型是河西走廊（地理区划）空间尺度上山洪灾害风险评价的优选模型;多准则决策模型不适用于张掖市（市域）空间尺度评价,且三个模型运行结果均没有河西走廊（地理区划）空间尺度上表现良好;三个模型的尺度效应明显,在地理区划空间尺度上应用较良好,缩小至市域空间尺度上模拟结果误差增大;不同空间尺度上,最大熵模型均优于多准则决策模型和信息量模型,适用于地理区划（大中）、市域（小）空间尺度的山洪灾害风险评价。     

Influence of Indian Ocean Dipole on Tropical Cyclone Activity over Western North Pacific in Boreal Autumn

In this study, we investigated the influence of the Indian Ocean Dipole(IOD) on the interannual variability of tropical cyclone(TC) activity over the western North Pacific(WNP) during autumn(September–November) from 1961–2015. We found the number of TCs making landfall in China to be significantly negatively correlated with the IOD index, which can be attributed to shifts in the location of TC formation together with the abnormal steering flow at 500 hPa. During negative IOD autumns, TC genesis regions move obviously westward due to the westward retreat of the WNP monsoon trough. The TC activity is remarkably enhanced near South China coastal areas, which is due to a contiguous 500-hPa subtropical ridge. In contrast, during positive IOD autumns, TC genesis positions obviously shift eastward and more TCs tend to exhibit recurvature around 130?E or a westward path south of 15?N led by an equatorward movement of the 500-hPa subtropical ridge with a break near 125?E. In our examination of large-scale circula-tion, we found a pair of equator-symmetric anticyclones in the lower troposphere resulting from variations in the large-scale Walker circulation induced by the anomalous sea surface temperature(SST) associated with a positive IOD. The resulting Philippines anti-cyclonic anomalies are closely related to the variability of the monsoon trough over the WNP region. Furthermore, the variations in the steering flow can be explained by the suppressed(enhanced) convective activities around the Philippines and the weakened(strengthened) local meridional circulation over East Asia in positive(negative) IOD years.     

Effects of Seawater Acidification on Early Development of Clam Cyclina sinensis

Anthropogenic emission of atmospheric carbon dioxide(CO_2) has led to a rapid increase in atmospheric CO_2 concentration. Increasing atmospheric CO_2 can reduce seawater pH and carbonate ions, which may adversely affect the survival of the larvae of calcareous animals. Cyclina sinensis is a commercially and ecologically important species in several Asian countries. Living in coast shallow waters, this species has experienced the coastal environmental changes frequently throughout its life cycle. In this study, we simulated possible future seawater pH values including 8.2, 7.8 and 7.4 and examined the effects of ocean acidification on the early development of C. sinensis. Clam embryos were incubated for 48 h(2 d) in control and high-CO_2 seawater to compare embryogenesis, larval growth and swimming behavior. Fertilization rate was quite sensitive to pH, and moderate acidification could induce a significant decrease in fertilization rate. However, only extreme acidification could bring significant negative effect to hatching rate, body size, and average path velocity of trochophora. Moreover, with seawater acidification, C. sinensis needs much more time to reach the same developmental stage, which increases the risk of larva survival. Together with recent studies demonstrating negative impacts of high CO_2 on fertilization and larva swimming behavior, the results imply a future decrease of C. sinensis populations in oceans if its acclimation to the predicted environmental alteration does not occur.     

Reverse-Time Migration of Converted S-Waves of Varying Densities

Ocean-Bottom Node(OBN) acquisitions provide both non-converted and converted reflection energy. There is a clear advantage to independently imaging both P-and S-waves, as they provide more information collectively than either does alone. In many conventional converted-wave pre-stack migration algorithms, density is treated as a constant, which is not the real-life case on earth. S-wave velocity and density information is crucial for hydrocarbon detection because it helps in the identification of porefilling fluids. In this paper, we focused on the effect of density on imaging, and developed a method of reverse-time migration(RTM) on converted s-waves of varying densities(VD-RTMCS). Phase correction was required prior to pre-stack migration to avoid constructive interference between data from adjacent sources. Synthetic data examples showed that when density variations were included, image profiles showed advantages in signal-to-noise ratio, vertical resolution and imaging of complex structures.     

Comparisons of Salinity Adaptation in Terms of Growth,Body Composition,and Energy Budget in Juveniles of Rainbow and Steelhead Trouts (Oncorhynchus mykiss)

This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout and anadromous steelhead trout. In the 42 d experiment, fish were cultured in three replicate tanks per salinity treatment(eight fish per tank). At the end of the experiment, the growth of rainbow and steelhead trouts was significantly higher at salinities of 5 and 10, respectively, than at all other salinities. The protein, lipid and energy content of both ecotypes declined with the increase of salinity. Based on their energy budgets, the percentage of energy consumed for growth by rainbow and steelhead trouts were significantly higher at salinities of 5(34.00% ±1.69%) and 10(43.76% ± 1.29%), respectively, than at all other salinities. The percentage of energy consumed for respiration by rainbow and steelhead trouts was lower at salinities of 5(54.90% ± 1.77%) and 10(46.73% ± 0.62%), respectively, than at all other salinities. Our results indicated that the salinity adaptation ability of juvenile steelhead trout was slightly better than that of juvenile rainbow trout, and salinities of 10 and 5, respectively, were most suitable for growth of these two fishes.     

Impacts of SIS and CICE as Sea Ice Components in BCC_CSM on the Simulation of the Arctic Climate

Sea ice is a sensitive indicator of climate change and an important component of climate system models. The Los Alamos Sea Ice Model 5.0(CICE5.0) was introduced to the Beijing Climate Center Climate System Model(BCC_CSM) as a new alternative to the Sea Ice Simulator(SIS). The principal purpose of this paper is to analyze the impacts of these two sea ice components on simulations of basic Arctic sea ice, atmosphere, and ocean states. Two sets of experiments were conducted with the same configurations except for the sea ice component used, i.e., SIS and CICE. The distributions of sea ice concentration and thickness reproduced by the CICE simulations in both March and September were closer to actual observations than those reproduced by SIS simulations, which presented a very thin sea ice cover in September. Changes in sea ice conditions also brought about corresponding modifications to the atmosphere and ocean circulation. CICE simulations showed higher agreement with the reference datasets than did SIS simulations for surface air temperature, sea level pressure, and sea surface temperature in most parts of the Arctic Ocean. More importantly, compared with simulations with SIS, BCC_CSM with CICE revealed stronger Atlantic meridional overturning circulation(AMOC), which is more consistent with actual observations. Thus, CICE shows better performance than SIS in BCC_ CSM. However, both components demonstrate a number of common weaknesses, such as overestimation of the sea ice cover in winter, especially in the Nordic Sea and the Sea of Okhotsk. Additional studies and improvements are necessary to develop these components further.