High-precision Q modeling and Q migration technology and its applications in loess plateau regions

The propagation of seismic waves in viscous media,such as the loess plateau and shallow gas regions,alters their amplitude,frequency,and phase due to absorption attenuation,resulting in reductions in the resolution and fi delity of seismic profi les and the inaccurate identifi cation of subtle structure and lithology.Q modeling and Q migration techniques proposed in this paper are used to compensate for the energy and frequency attenuation of seismic waves,obtain high-quality depth imaging results,and further enhance structural imaging to address the aforementioned problem.First,various prior information is utilized to construct an initial Q model.Q tomography techniques are employed to further optimize the precision of the initial Q model and build a high-precision Q model.Subsequently,Q prestack depth migration technology is employed to compensate for absorption and attenuation in the three-dimensional space along the seismic wave propagation path and correct the travel times,realizing the purposes of amplitude compensation,frequency recovery,and phase correction,which can help improve the wave group characteristics while enhancing the resolution.Model data and practical application results demonstrate that high-precision Q modeling and Q migration techniques can substantially improve the imaging quality of underground structures and formations in the loess plateau region with extremely complex surface and near-surface conditions.The resolution and fi delity of seismic data,as well as the capability to identify reservoirs,can be improved using these techniques.

Study on Rural Domestic Waste Treatment in Loess Plateau Region——Taking Longfang Town in Shaanxi Province as Example

With the continuous development of economy and changes in people’s lifestyle,rural domestic waste brought about serious harm to water,air,human health,ecological landscape and so forth.In this paper,taking Longfang Town in Loess Plateau region as example,the source,amount and harms of rural domestic waste were analyzed firstly,as well as the current situation and existing problems of treatment,and then a suitable waste disposal technology for the town was chosen,finally the reasonable treatment methods combining new countryside and non-new countryside with township was summed up,so as to realize the reduction,harmless and resource treatment of rural domestic waste.

Study on the Climate Changes Characteristics in the Hilly Region of the Loess Plateau and Its Influence on Agricultural Production

[Objective] The aim was to study the climate changes characteristics in the hilly region of the loess plateau and its influence on agricultural production.[Method] Taking Yan’an City as an example,and by dint of temperature and precipitation in nine meteorological stations from 1957 to 2007 and accumulated anomaly curve,linear regression and relevant analysis,the climate changes characteristics in 51 years in Yan’an were expounded.The climate changes in the hilly region of the loess plateau were studied and its influences on agricultural production were concluded.[Result] The characteristics of climate changes in the hilly region were as follow:high temperature in winter and warm winter trend was clearly;the temperature in spring enhanced fast and the drought disaster was increasing worse;rainy days occurred now and then in autumn.The climate changes had different levels of influences on agricultural production in Yan’an City.Because of rising temperature in winter,facility agriculture was vigorously developed and the apple range expanded;in the meantime,because of rising temperature in spring,drought was worsen and sowing in spring can not proceed;constant rain in autumn damaged the quality of date.[Conclusion] The study provided theoretical basis for the regional agricultural production and agricultural structure adjustment.

Land-use changes in the small watershed of the Loess Plateau,hilly-gully region, China

As more and more farmland is converted to forestry, the need for effective decision support regarding the use of land in the fragile ecological environment of the Loess Plateau hilly-gully area. The Luoyugou watershed was chosen as the study area to calculate the single dynamic degree, integrated dynamic degree, and change indexes of land use, as well as the land-use type transition matrix. This was done by interpreting the TM and SPOT images of the Luoyugou watershed in 1986, 1995, and2004 and making statistical analysis. The results of ou statistical analysis show that the conversion of slope farm land to terrace and forest land plays a dominant role in land-use changes in the Luoyugou watershed from 1986 to2004. The land-use changes are mainly driven by popula tion growth, socio-economic development, consume spending, and investment in forest ecology.

Dynamic Land Use /Cover Change and Analysis of Landscape Pattern in the Hilly and Gully Region of Loess Plateau: A Case Study of Pengyang County in Southern Ningxia

The quantitative evaluation on land use /cover change as well as its influence on landscape pattern under the background of returning grain plots to forestry is significant to the sustainable utilization of land resources and ecological environment reconstruction in the southern Ningxia.Based on multi-temporal remote sensing data from four periods of Landsat TM /ETM,and combination of ecological quantity analytical method with GIS,the change of land use /cover and landscape pattern in Pengyang County of Ningxia Province were analyzed.The conclusions showed that the amount of each land use type was changed with different degrees,the area of forest /grass land increased,while farmland and unused land decreased.The change of landscape pattern was characterized as that the degree of landscape fragmentation,mixed distribution of patches,diversity index and evenness index increased gradually and then decreased,the connectivity between patches decreased gradually and then increased,and landscape shape presented irregular.

Autumn Daily Characteristics of Land Surface Heat and Water Exchange over the Loess Plateau Mesa in China

The Loess Plateau, located in northern China, has a significant impact on the climate and ecosystem evolvement over the East Asian continent. In this paper, the preliminary autumn daily characteristics of land surface energy and water exchange over the Chinese Loess Plateau mesa region are evaluated by using data collected during the Loess Plateau land-atmosphere interaction pilot experiment （LOPEX04）, which was conducted from 25 August to 12 September 2004 near Pingliang city, Gansu Province of China. The experiment was carried out in a region with a typical landscape of the Chinese Loess Plateau, known as ＂loess mesa＂. The experiment＇s field land utilizations were cornfield and fallow farmland, with the fallow field later used for rotating winter wheat. The autumn daily characteristics of heat and water exchange evidently differed between the mesa cornfield and fallow, and the imbalance term of the surface energy was large. This is discussed in terms of sampling errors in the flux observations-footprint; energy storage terms of soil and vegetation layers; contribution from air advections; and low and high frequency loss of turbulent fluxes and instruments bias. Comparison of energy components between the mesa cornfield and the lowland cornfield did not reveal any obvious difference. Inadequacies of the field observation equipment and experimental design emerged during the study, and some new research topics have emerged from this pilot experiment for future investigation.

Vegetation and environmental changes in western Chinese Loess Plateau since 13.0 ka BP

Pollen records from the Chinese Loess Plateau revealed a detailed history of vegetation variation and associated climate changes during the last 13.0 ka BP. Before 12.1 ka BP, steppe or desert-steppe vegetation dominated landscape then was replaced by a coniferous forest under a generally wet climate （12.1-11.0 ka BP）. The vegetation was deteriorated into steppe landscape and further into a desert-steppe landscape between 11.0 and 9.8 ka BP. After a brief episode of a cool and wet climate （9.8-9.6 ka BP）, a relatively mild and dry condition prevailed during the early Holocene （9.6-7.6 ka BP）. The most favourable climate of warm and humid period occurred during mid-Holocene （7.6-4.0 ka BP） marked by forest-steppe landscape and vegetation alternatively changed between steppe and desert-steppe from -4.0 to -1.0 ka BP.

Dynamic Simulation of Land Use in the Southern Loess Plateau

To study the dynamic changes of land use and predict the future land use scenarios based on the current land use,this paper uses Cellular Automata- Markov( CA- Markov) model to simulate the landscape pattern in 2030. The results show that in the study area during the period 1980- 2005,grassland and construction land increased,and woodland increased slightly; waters and unused land decreased,and arable land underwent dramatic changes. The simulation precision of CA- Markov model is 87. 28%,indicating that the use of it for simulation is reliable. The land use of the study area will be changed greatly in the future. This method provides a reference for the regions to carry out land prediction,and the research results can provide a basis for the study of optimization of land.

THE SYSTEMATIC DYNAMIC EMULATION ON THE AGRICULTURAL DEVELOPMENT ON THE LOESS PLATEAU

The Loess Plateau, covered with thick loess, lies in the middle reaches of the YellowRiver to the west of the Taihangshan Mountains, east of the Wuqiao Mountains south ofYinshan Mountains and north of the Qinling Mountains with a total area of 56×10~4km^2.The plateau is 1000--2500m above sea level and has loess as thick as 100--200 metres, be-

Review on Regional Climate Change Induced by Qinghai-Tibet Plateau Uplift

[Objective]The aim was to study the influence of Qinghai-Tibet Plateau uplift on regional climate in China.[Method] Trough relevant study of Qinghai-Tibet Plateau and its surrounding movement,the tectonic movement of the Qinghai-Tibet Plateau and its surrounding areas,especially the case of the impact caused by plateau phased uplift were studied based on paleomagnetic measurements.[Result]The increasing Qinghai-Tibet Plateau led to obvious transition from dry to cold in northwest China and it became dry quickly,which led to loess accumulation,replacement of vegetation types and human activity.Meanwhile,it was dry,and there was certain degree of climate changes in the area.[Conclusion] Qinghai-Tibet Plateau had far-reaching significance on basic climate characteristics in northwest China.

黄土高原次沟流域样条分区谱系建构与规划设计导控研究

次沟流域是黄土高原丘陵沟壑区城乡发展的重要潜在区域,但其狭长的沟谷空间内地形复杂、多系统复合,孕育出了复杂的人地关系,城市规划的一般经验与方法较难适用于这种独特的地域环境,导致该区域规划建设存在诸多问题。将“城乡空间样条断面”方法引入次沟流域规划,遵循人地和谐共生理念并从“自然环境生态性、聚落建设适宜性、人居发展程度”3个维度绘制次沟流域样条分区谱系图,定义“T3-a发展成熟区、T3-b发展潜力区、T2-a适度收缩区、T2-b维持平衡区、T1-a生态治理区、T1-b生态服务区、T1-c生态保育区”7类样条分区;基于次沟流域样条分区的不同特征与问题,确定各分区的职能定位与发展导向,从聚落空间秩序、营建模式、功能设施及生态景观等方面对次沟分区规划设计提出差异化的导控规则与指标,以促进次沟流域人居环境与自然环境的健康良性发展,为黄土高原丘陵沟壑区规划设计提供具有可操作性的决策依据。

黄土高原河谷城镇“川—沟”融合单元发展路径研究

通过分析黄土高原河谷城镇独特的城乡关系与发展困境,认为川道与次沟空间结构一体化、功能结构差异化发展是振兴黄土高原丘陵沟壑区的重要突破口,由此提出“川—沟”融合单元的概念内涵与划定方法。以榆林市绥德县为例,打破镇域行政边界和小流域镇村体系,基于川道城镇和次沟乡镇的空间关联关系划定10个融合单元,并从用地形态结构、产业经济地理、服务设施配置等方面对融合单元的空间构型、功能类型和服务水平进行剖析,探讨川道与次沟协同视角下以融合单元为抓手推动黄土高原河谷城镇高效发展和管控治理的新路径。

文化保护与乡村振兴协同的杨家沟建设规划研究

以杨家沟为代表的一类特殊乡村具有红色文化资源丰富但地处偏远、对外交通不便、产业基础薄弱、土地资源紧缺等特征,长期面临红色文化资源保护与乡村振兴的双重压力.基于乡村地域系统理论与评估框架,诊断杨家沟乡村子系统发展水平及问题,结果表明:杨家沟乡村子系统呈两极化发展水平,虽然红色文化资源丰富、历史文化底蕴深厚,但在生态环境脆弱、土地资源紧缺、遗产保护要求约束的影响下,该村农业和旅游业难以充分发展,导致人口外流、产业空心化、经济发展缓慢,进一步加剧遗址维护人员及资金短缺、遗址保护管理不善等问题.对此,规划提出“红色文化+X”的发展模式,形成文化遗产带动红色旅游、红色旅游反哺遗产保护、促进乡村振兴的良性循环,并采用“枝状网络分形”的空间布局,解决遗址环境保护与旅游产业发展、移民搬迁安置的潜在用地冲突.

黄土高原近30年降水集中度分析及时空演变特征

选取近30年的黄土高原地区58个气象站点的降水数据,分析了黄土高原年降水以及降水集中度(PCD)和集中期(PCP)的时空变化特征,结果表明:(1)黄土高原地区年均降水量在50~900 mm,空间分布上东南高西北低。降水高值区分布在三门峡站与武功站附近以及五台山站,年均降水量为900 mm;低值区位于临河站附近,年均降水量为50 mm;(2)黄土高原地区的降水集中度分布于0.43~0.76,自东南向西北递增;而降水集中期的变化则不太明显,多集中于夏季的7-8月份。因此在降水集中的7-8月份,水土流失会比较加重,应加强水土流失防治工程,在降水量大的月份做好灾害防护,为工农业生产提供预警,减少工农业生产损失与经济损失。

2005-2019年陕西长武农田生态系统国家野外科学观测研究站气象数据集

陕西长武农田生态系统国家野外科学观测研究站(长武站)所在区域代表了黄土高塬沟壑区的典型农田,在研究站内设置气象自动观测系统对气象要素进行长期定位观测,对该区气候变化背景下农田生态系统水、土、气、生过程研究具有重要意义。本数据集对2005–2019年长武站的原始气象数据进行处理、质量控制和评估,对大气温度、相对湿度、降水量、大气压、总辐射、反射辐射、紫外辐射、净辐射、光合有效辐射、日照时数和各土层土壤温度(0 cm、5 cm、10 cm、15 cm、20 cm、40 cm、60 cm和100 cm)18项气象观测指标,以180条月尺度和15条年尺度的格式进行信息公开,以期为黄土高原沟壑区农业生态研究、天气灾害预警和气候生产潜力模拟等提供基础数据支撑。

Spatial distribution and influencing factors of Surface Nibble Degree index in the severe gully erosion region of China’s Loess Plateau

In China’s Loess Plateau severe gully erosion(LPGE)region,the shoulder-line is the most intuitive and unique manifestation of the loess landform,which divides a landform into positive and negative terrains(PNTs).The spatial combination model of PNTs is of great significance for revealing the evolution of the loess landform.This study modeled and proposed the Surface Nibble Degree(SND),which is a new index that reflects the comparison of the areas of PNTs.Based on 5 m DEMs and matched high-resolution remote sensing images,the PNTs of 164 complete watersheds in the LPGE were extracted accurately,and the SND index was calculated.The spatial distribution trend of SND was discussed,and the relationship between SND and the factors that affect the evolution mechanism of regional landform was explored further.Results show that:(1)The SND can be calculated formally.It can quantify the development of the loess landform well.(2)The SND of the LPGE has evident spatial differentiation that increases from southwest to northeast.High values appear in Shenmu of Shaanxi,Shilou of Shanxi,and northern Yanhe River,whereas the low values are mainly distributed in the southern loess tableland and the inclined elongated ridge area of Pingliang in Gansu and Guyuan in Ningxia.(3)In the Wuding River and Yanhe River,the SND decreases with the increase in flow length(FL).In the North-Luohe River and Jinghe River,the SND increases with FL.(4)SND is significantly correlated with gully density and sediment modulus and moderately correlated with hypsometric integral.As for the mechanism factors analysis,the relationship between loess thickness and SND is not obvious,but SND increased first and then decreased with the increase of precipitation and vegetation in each geographical division,and we found that the land use type of low coverage grassland has greater erosion potential.

The effect of environmental factors on spatial variability in land use change in the high-sediment region of China＇s Loess Plateau

In areas with topographic heterogeneity, land use change is spatially variable and influenced by climate, soil properties, and topography. To better understand this variability in the high-sediment region of the Loess Plateau in which soil loss is most severe and sediment diameter is larger than in other regions of the plateau, this study builds some indicators to identify the characteristics of land use change and then analyze the spatial variability as it is affected by climate, soil property, and topography. We build two indicators, a land use change intensity index and a vegetation change index, to characterize the intensity of land use change, and the degree of vegetation restoration, respectively. Based on a subsection mean method, the two indicators are then used to assess the spatial variability of land use change affected by climatic, edaphic, and topographic elements. The results indicate that： 1） Land use changed significantly in the period 1998-2010. The total area experiencing land use change was 42,302 km2, accounting for 22.57%of the study area. High-coverage grassland, other woodland, and forest increased significantly, while low-coverage grassland and farmland decreased in 2010 compared with 1998.2） Land use change occurred primarily west of the Yellow River, between 35 and 38 degrees north latitude. The four transformation types, including （a） low-coverage grassland to medium-coverage grassland, （b） medium-coverage grassland to high-coverage grassland, （c） farmland to other woodland, and （d） farmland to medium-coverage grassland, were the primary types of land use change, together constituting 60% of the area experiencing land use change. 3） The spatial variability of land use change was significantly affected by properties of dryness/wetness, soil conditions and slope gradient. In general, land use changed dramatically in semi-arid regions, remained relatively stable in arid regions, changed significantly in clay-rich soil, remained relatively stable in clay-poor soil, changed dramatically in steeper slopes, and remained relatively stable in tablelands and low-lying regions. The increase in vegetation coincided with increasing changes in land use for each physical element. These findings allow for an evaluation of the effect of the Grain to Green Program, and are applicable to the design of soil and water conservation projects on the Loess Plateau of China.

Comprehensive analysis of changes to catchment slope properties in the high-sediment region of the Loess Plateau, 1978-2010

To control soil erosion and restore the degraded environment in the Loess Plateau, a large number of measures related to soil and water conservation have been employed that have profoundly affected catchment properties. This study constructed three indicators to characterize changes to the catchment slope, proposed both a method for a regression analysis of adjacent images and a sequence model, and applied multisource remotely sensed images and GIS spatial clustering analysis technologies to extract thematic information and comprehensively analyze the catchment change characteristics. The results indicate that the catchment slope properties changed significantly. At catchment scale, the average values of ARC, DVC and ART were 6.43%, 25.57% and 4.30%, respectively. There were six clustering types of catchment slope property changes. The maximum and minimum of the average similarities of the clustering types were 0.992 and 0.935. Each slope control measures had a distinct effect on catchment slope; the dominating factor of each clustering type was identified as： Type 1： D-VC, Type 2： D-VCLU, Type 3： D-LUVC, Type 4： D-TAVC, Type 5： D-TAC and Type 6： D-MFC. Type 5 and Type 1 covered the largest areas, respectively occupying 37.28% and 31.01%. Catchment slope property changes also had distinct types that depended on their geomorphological conditions. These findings provide a useful basis from which to further study catchment slope hydrological and soil erosion processes.

双螺孔型重建板前路双关节融合术治疗黄土高原地区晚期踝大骨节病

目的探讨双螺孔型重建板前路双关节融合术治疗黄土高原地区晚期踝大骨节病的疗效。方法采用双螺孔型重建板前路双关节融合术治疗36例黄土高原地区晚期踝大骨节病患者。记录手术情况、疼痛VAS评分、AOFAS踝-后足评分以及并发症发生情况。结果患者均获得随访,时间6~20(9.4±2.2)个月。手术时间50~60(55.0±5.0)min。切口均一期愈合,术后未发生断钉、断板等并发症。疼痛VAS评分及AOFAS踝-后足评分:术后6个月、末次随访时均较术前改善(P<0.05)。末次随访时,X线片显示踝关节植骨均融合,患侧外观正常,患肢行走无明显不适感;采用AOFAS踝-后足评分评价疗效:优30例、良6例,优良率100%。结论采用双螺孔型重建板前路双关节融合术治疗黄土高原地区晚期踝大骨节病,术中能够充分处理关节面,实现坚强固定,术后能够较好地恢复和维持踝关节的矫形位置,并发症少,疗效满意。

Spatial distribution of surface rock fragment on hillslopes in a small catchment in wind-water erosion crisscross region of the Loess Plateau

The cover and size distributions of surface rock fragment in hillslopes were investigated by using digital photographing and treating technique in a small catchment in wind-water erosion crisscross region of the Loess Plateau. The results indicated that the maximal cover of rock fragment was pre-sented at mid-position in steep hillslope. Rock fragment presented a general decreasing-trend along the hillslope in gentle hillslope. Rock fragment cover was positively related to gradient, rock fragment size decreased generally along the hillslope, and the size reduced with the gradient. The mean size of rock fragment was at a range of 6―20 mm in the steep hillslope, rock fragment size > 50 mm was rarely presented. The covers of rock fragment at different positions were markedly related to the quantities of rock fragment < 40 mm. The area of rock fragment of 2―50 mm accounted for 60% or more of the total area, dominating the distribution of rock fragment in the hillslopes.