Land Use/Cover Change and Its Policy Implications in Typical Agriculture-forest Ecotone of Central Jilin Province,China

During the 21 st century, policies toward agriculture, forestry, and urbanization have emerged to ensure food security, ecological restoration, and human well-being by managing land in Northeast China. However, the integrated effects and relationships of various policies are still not well understood. This study observed the land use land cover changes in Central Jilin from 2000 to 2019 and, by considering policy involvement, aimed to understand the effects and trade-offs of policies. Results showed that the cropland, including dryland and rice paddy, and the forest, including coniferous forest and deciduous forest, are dominant land types in Central Jilin. During2000–2019, the land changed diversely, of which the main changes were the expanded dryland(+0.43 million ha), the increased deciduous forest(+22 million ha), the decreased coniferous forest(–0.08 million ha), and the expanded urban settlement(+0.04 million ha).With these changes, despite the unit grain yield showing a rising trend, the yield contribution of Central Jilin to the national total decreased. The poor cultivating structure made for the cropland expansion and reduced the implementation space of environmental restoration projects such as the Grain to Green. Thus, in Central Jilin that transits from the agri-food production zone to the eco-regulation zone, environmental projects coexisted in a trade-off manner with agricultural policies that aim to liberate agricultural productivity. In the key urban agglomerations of Central Jilin, the increase in the proportion of green space improved the thermal environment and carbon balance. The gross domestic product of the large city and its local proportion also rose. These improvements benefited from the promotion of development policies and urbanization policies at key time points. In the future, it is necessary to coordinate agricultural policies and environmental projects and promote the progress of small-and medium-sized cities to ensure the equality of regional development. This study has implications for making decisions to revitalize Northeast China and researchers who inform decisions.     

基于GF-3和Landsat 8遥感数据的土壤水分反演研究

基于我国首颗全极化雷达卫星高分三号（GF-3）和Landsat8数据,研究浓密植被覆盖地表土壤水分反演方法。为了提高浓密植被覆盖地表土壤水分反演精度,首先利用PROSAIL模型、实测植被参数及Landsat8光学数据分析了8种植被指数与植被冠层含水量的相关性,从中优选出归一化差异水指数（NDWI₅）用于反演植被冠层含水量,并通过分析植被含水量和植被冠层含水量的关系,构建植被含水量模型;然后结合植被含水量反演模型和简化MIMICS模型校正了植被对雷达后向散射系数的影响,最后基于AIEM建立裸土后向散射系数模拟数据集,发展一种主动微波和光学数据协同反演浓密植被覆盖地表土壤水分模型,并以山东省禹城市为研究区,实现了玉米覆盖下HH、VV和HH+VV 3种模式土壤水分反演。实验结果表明： ① NDWI₅为最佳植被指数,对于去除植被影响有较好效果;② 基于此方法,利用GF-3和Landsat8卫星数据反演得到的土壤水分具有较高的精度;③ 相比HH和VV两种极化模式,HH+VV双通道模式对土壤水分反演结果更好,决定系数（R2）为0.4037,均方根误差（RMSE）为0.0667 m ³m ^-3。     

The Improved Simulated Annealing Algorithm and Application in the Surface Wave Dispersion Inversion

The velocity distribution of layers from surface wave dispersion curve is a severely nonlinear program. Base on the Metropolis rule,we improved the simulated annealing algorithm to simultaneously inverse the velocities and thicknesses using the dispersion data and identified the Moho and the bottom of lithosphere. The application to the numerical examples with 5% noise shows the velocity RMS is 1. 56% between the non-linear results and the original models when the condition of selecting method for temperature parameters and initial temperature are satisfied. Using the pure dispersions of Rayleigh wave,the nonlinear inversion has been carried out for S-wave velocities and thicknesses of the vertical profile crossing the Indian Plate,the Qinghai-Tibetan Plateau,and the Tarim Basin. It indicated that the crustal thickness is about 70 km in the Qiangtang block,while in the hinterland of the Qinghai-Tibetan Plateau the lithosphere is relatively thin(～ 130 km)from the velocity values and their offsets.     

2016年12月8日新疆呼图壁MS6.2地震发震构造初步研究

2016年12月8日呼图壁县发生M_S6.2地震,由于初始定位误差较大,余震序列分布离散,对呼图壁地震的发震断层尚不清楚。本研究采用CAP方法反演主震及余震中M_S ≥ 3.5地震的震源机制解,并采用双差定位方法对余震进行重定位,得到了637个地震的震源参数。结果显示,呼图壁地震主震的最佳双力偶节面解为：节面Ⅰ走向82°,倾角18°,滑动角61°;节面Ⅱ走向292°,倾角74°,滑动角98°。其中节面Ⅱ为本次地震的破裂面。重定位后,主震的震源位置被重定为（86.36°E,43.79°N）,震源深度14 km,根据余震的分布特点、震源机制解特征和区域构造特征,呼图壁地震的发震断层并不是南倾的准噶尔南缘断裂,而是在其北边的霍尔果斯-玛纳斯-吐谷鲁断裂带上的一个反冲断层。在北天山区域内,由于构造反转的作用,存在诸多倾角在45°~55°之间的北倾的断层。根据GPS的资料显示,天山北部地区的应力在新生代晚期已开始积累,这增加了天山北部前缘的发震概率。     

太湖流域典型水源水库藻类水华的促发条件

藻类异常增殖引发的水华是威胁我国水源地水库的主要生态问题之一。探究水源水库中藻类异常增殖的促发因素是防控藻类水华水质问题的前提。本文以太湖流域两个大(Ⅱ)型中营养水库为例,通过周年浮游植物细胞密度、生物量及相关环境因子逐月监测,分析影响水库有害藻类生物量季节性异常增殖特征及其促发条件。结果表明,地处亚热带季风区的两个水源水库均存在蓝藻和硅藻阶段性异常增殖的风险,老石坎水库5月暴发了以曲壳藻为绝对优势种的重度硅藻水华现象,硅藻细胞密度达到6232×10⁴ cells/L,赋石水库则在6和9月均出现了蓝藻细胞数达到水华级别的异常增殖现象。冗余分析表明,总磷、水温和水位是影响水库硅藻、蓝藻异常增殖的关键因素。非线性回归等统计分析表明,两个水库中水体总磷浓度显著影响藻类异常增殖强度的临界值为0.024 mg/L,而水温高于16℃时,硅藻水华事件可能发生,硅藻水华发生的最佳温度为22℃水温高于20℃时,蓝藻水华事件可能发生,蓝藻水华发生的最佳温度为30℃持续低水位或水位快速波动过程中藻类水华暴发的风险较高。研究表明,太湖流域中营养水源水库藻类异常增殖或藻类水华的发生往往是营...     

论土体结构各层次的功能及其相互关系

土体广泛分布于地球的表层,是一个十分复杂的自然体。本文在论述了土体7个结构层次功能的基础上,从系统科学的角度阐述了各层次之间的辩证关系,包括低层次是高层次结构的基础;高层次对低层次结构的影响;层次间的协同作用;层次间交错、重叠与演变等。在与土体相关的研究工作和工程实践中,将土体作为一个系统进行合理的层次划分和分析,有助于复杂问题的简化,从而全面正确地掌握土体的工程性质及其形成机理。     

面向对象的特色农作物种植遥感调查方法研究

宁夏自治区具有土地、光能、引黄灌溉等优势,为宁夏特色农作物（硒砂瓜、枸杞、大枣）的生长提供了先天条件。快速准确地获取特色农作物的种植信息不仅是宁夏特色农作物监测、估产和灾害评估的重要依据,同时也是分析特色农作物结构分布变化和评价区域特色农业生产影响的重要凭证。近年来,随着航天技术和卫星传感器的不断发展,越来越多的学者将遥感技术运用到农作物种植信息的提取研究中。但是传统的遥感调查模型都是基于中低分辨遥感数据建立的,对于新的高分数据没有完备的信息提取模型。此外,基于GF-1遥感影像对类似宁夏特色农作物（硒砂瓜、枸杞、大枣）的信息提取研究相对较少,决策条件和分类模型的选择也难以满足高分农业的需求。基于此,本文利用国产GF-1 PMS遥感影像,在分析3类特色农作物光谱特征和纹理特征的基础上,建立了面向对象的支持向量机（SVM）分类模型,总体分类精度达到94.94%,Kappa系数为0.9174。同时将分类结果与传统的SVM分类结果相比较,研究发现面向对象的SVM模型的精度更高,效果最好,纹理信息的引入使光谱特征差异较小的枸杞和大枣更容易区分,有效降低了模型错分和漏分误差,改善了模型分类结果。研究结果为实现宁夏特色农作物的快速自动化提取提供了有效途径,也为开展农作物承保和受灾定损评估体系建设提供技术支撑。     

Estimation of genetic parameters for upper thermal tolerances and growth-related traits in turbot Scophthalmus maximus

An abnormally high temperature produces a stress response in turbot causing large economic losses in the turbot aquaculture industry of China. A genetic improvement of the upper thermal tolerance (UTT) of turbot could allow cultured fi sh to adapt. A genetic evaluation of UTT is required for determining the practicability of including this trait into a breeding program. In this study, data were recorded from a temperature tolerance test conducted on 3 200 individual turbots from 32 full-sib groups. A cross-sectional linear model and a cross-sectional threshold probit model were used to analyze the test-period survival and a cross-sectional threshold logit model was used to analyze the test-day survival. In addition, phenotypic and genetic correlations between body weight and survival data were estimated. The estimated heritability values obtained from the cross-sectional linear model (CSL), the cross-sectional threshold (probit) model (THRp), and the cross-sectional threshold (logit) model (THRl) were 0.247 9±0.108 3, 0.288 3±0.161 2, and 0.106 9±0.045 2, respectively. The correlation coeffi cients among the full-sib family estimated breeding values (EBVs) obtained from the three models were greater than 0.998 6 and all models produced an almost identical family ranking. The accuracies of selection obtained with the CSL, THRp, and THRl model were 0.773 8, 0.775 4, and 0.784 4, respectively, the greatest from the THRl model. The genetic correlations between body weight and survival data EBVs from the CSL, THRp, and THRl models were 0.020 1,-6.201 1×10^-4 , and -3.115 4×10^-4 , respectively, and the phenotypic correlations between the two traits were -0.837 1 and -0.667 1, respectively. The findings of this study provide background information to determine the best strategy of selection for the genetic improvement of UTT in turbot.     

中国东海和南海4个真虾(甲壳动物亚门:十足目:真虾下目)新记录种

采集自中国东海和南海的4个真虾物种,经研究发现为中国海域的新记录物种,即凯氏鞭腕虾（Lysmata kempi Chace,1997）,利普克鞭腕虾（Lysmata lipkei Okuno&Fiedler,2010）;透明近绿虾（Chlorocurtis jactans（Nobili,1904））和黑斑活额虾（Rhynchocinetes conspiciocellus Okuno&Takeda,1992）。本文描述了这四个物种的形态特征,编制了检索表,并对其分类地位进行了讨论。     

基岩面形状对土体变形破坏的影响实验研究

采用离心模型试验研究基岩面形状对重力式加筋挡土墙土体变形破坏的影响,基岩面形状设置为直线形和台阶形,直线情况下基岩与挡墙分别围成三角形和梯形,台阶则分为两级台阶和三级台阶,试验共进行4组。试验结果表明,水平位移和沉降变化剧烈的位置主要在土体顶部靠近挡墙的位置,近岩面处土体水平位移和沉降都比较小;在挡土墙底部基岩与挡墙之间应当有足够的水平距离才有利于土体的稳定;基岩与挡墙所围形状为三角形时对土体的变形和稳定最为不利,基岩与挡墙围成梯形或基岩为台阶形时对土体稳定比较有利。