Transfer Matrix Analysis Research Articles

Experimental synthesis of random pressure fields based on Transfer-Matrix analysis on 1D arrays

Synthesizing random pressure fields with loudspeaker arrays in a laboratory setting requires acquiring a global transfer matrix of all channels between the loudspeaker array and the microphone array. This inevitably involves measuring a large and unwieldy number of transfer functions. Therefore, we propose a prediction method for the transfer matrix under free-field conditions, combining a substantially reduced number of measurements with specific predictions based on segmented acoustic centers. In free-field conditions, if only three sets of transfer functions are measured for each loudspeaker and the remaining entries in the global transfer matrix are predicted using analytical expressions, the results show that the normalized error between the predicted and measured transfer matrices can be less than -13 dB. The experimental results indicate that, based on a one-dimensional loudspeaker array in a standard anechoic chamber, this prediction method shows promise for accurately reproducing random pressure fields, such as a diffuse acoustic field and the pressure field in the spanwise direction of a turbulent boundary layer. Additionally, the prediction method demonstrates the potential for extension to two-dimensional synthesis.

Asymmetric transfer matrix analysis of Lyapunov exponents in one-dimensional nonreciprocal quasicrystals

Asymmetric transfer matrix analysis of Lyapunov exponents in one-dimensional nonreciprocal quasicrystals

Enhancing railway noise reduction through advanced multilayer acoustic absorbent systems with tunable resonators

Railway noise poses a significant environmental challenge, prompting the need for effective mitigation strategies. In response, noise barriers are often employed to reduce noise near railways. This research focuses on the use of porous materials, more specifically porous concrete, for acoustic absorption, particularly in the context of railway noise reduction. A novel approach is proposed, wherein porous multilayer metamaterial systems are developed, with each layer's macroscopic parameters strategically optimized to enhance the overall sound absorption curve. Additionally, to broaden the frequency range of noise attenuation, tunable resonators are seamlessly integrated into the multilayer system. The analytical framework for analyzing both the multilayer system and resonators involves employing equivalent fluid models and the analytical transfer matrix method. Linear regressions were employed to establish relationships between porosity, density, and other macroscopic parameters, enabling the derivation of the sound absorption curve solely from these parameters. Through systematic optimization and integration of resonators, it is expected that, the proposed approach demonstrates significant advancements in railway noise reduction efficacy across a wide frequency range. This research aims to contribute to the development of more efficient and versatile acoustic absorbent systems for mitigating railway noise pollution.

Analytical equation for camera imaging with refractive interfaces

Camera imaging through refractive interfaces is a crucial issue in photogrammetric measurements. Most past studies adopted numerical optimization algorithms based on refractive ray tracing procedures. In these studies, the camera and interface parameters are usually calculated iteratively with numerical optimization algorithms. Inappropriate initial values can cause iterations to diverge. Meanwhile, these iterations cannot efficiently reveal the accurate nature of refractive imaging. Therefore, obtaining camera calibration results that are both flexible and physically interpretable continues to be challenging. Consequently, in this study, we modeled refractive imaging by employing ray transfer matrix analysis. Subsequently, we deduced an analytical refractive imaging (ARI) equation that explicitly describes the refractive geometry in a matrix form. Although this equation is built upon the paraxial approximation, we executed a numerical experiment that shows that the developed analytical equation can accurately illustrate refractive imaging with a considerable object distance and a slightly tilted angle of the flat interface. This ARI equation can be used to define the expansion center and the normal vector of the flat interface. Finally, we also propose a flexible measurement method to determine the orientation of the flat interface, wherein the orientation can be measured rather than calculated by iterative procedures.

Spatiotemporal Patterns of Vegetation Evolution in a Deep Coal Mining Subsidence Area: A Remote Sensing Study of Liangbei, China

This study aims to provide a comprehensive analysis of the impacts of high-intensity coal mining on vegetation in Liangbei Town, a typical deep coal mining area in central of China. Using Landsat remote sensing data from 2000 to 2023, processed by the Google Earth Engine (GEE) platform, the study calculates the Normalized Difference Vegetation Index (NDVI). Temporal and spatial distribution patterns of vegetation were assessed using LandTrendr algorithm, Sen’s slope estimation, the Mann–Kendall test, the coefficient of variation, and the Hurst index. Vegetation growth dynamics were further analyzed through transfer matrix and intensity analysis frameworks. Driving factors influencing vegetation trends were evaluated using local climate data and surface deformation variables from SAR imagery. Temporal Dimension: From 2000 to 2023, the annual NDVI in Liangbei Township showed an upward trend with a growth rate of 0.0894 (10a)−1, peaking at 0.51 in 2020. Spatial Dimension: The NDVI distribution in Liangbei Township displayed a pattern of being lower in the center and higher around the edges, with values concentrated between 0.4 and 0.51, covering 50.34% of the total area. Trend of Change: Between 2000 and 2023, 83.28% of the area in Liangbei Township experienced significant improvement in the NDVI, with vegetation growth trends shifting primarily from slight to significant improvement, encompassing a total area of 10.98 km². This shift exhibited a marked tendency. Driving Factors: Deep mining in Liangbei Township is concentrated in the eastern part, with SAR imagery indicating a maximum surface subsidence of 0.26 m. As surface subsidence increases, the NDVI significantly decreases. The findings suggest that in the future, 91.13% of the vegetation in Liangbei Township will display an antipersistent change trend. The study offers critical insights into the interaction between mining activities and vegetation cover can serve as a reference for environmental evolution and management in similar mining areas.

Network- and CFD/CAA-modelling of the high frequency flame response in multi-jet combustors

Low order networks are widely used for linear stability analysis of combustors in the low frequency limit. High frequency stability analysis, however, is limited to cost-intensive numerical or experimental methods, since derivation of analytical solutions is either cumbersome or impossible. The article at hand provides a quasi-two-port network model for the effective modal acoustic pressure and axial velocity normalised with the transverse acoustic field for cylindrical combustors. This network modelling approach includes transfer matrices of acoustic area jumps, ducts for longitudinal, standing and spinning transverse and mixed mode wave propagation. The purely acoustic transfer matrices are validated with a generic non-reactive experiment. On the basis of phase-locked [Formula: see text] images of an engine-similar multi-jet combustor with a forced T1 mode, a locally distributed flame response model is derived, which is reduced to a global flame transfer matrix. A locally resolved convective flame response model is implemented in a numerical model in order to verify the provided theory by the comparison of the analytical and numerical flame transfer matrix for the high-frequency regime.

An Anti-Forensics Video Forgery Detection Method Based on Noise Transfer Matrix Analysis.

The dispute over the authenticity of video has become a hot topic in judicial practice in recent years. Despite detection methods being updated rapidly, methods for determining authenticity have limitations, especially against high-level forgery. Deleting the integral group of pictures (GOP) length in static scenes could remove key information in the video, leading to unjust sentencing. Anyone can conduct such an operation using publicly available software, thus escaping state-of-the-art detection methods. In this paper, we propose a detection method based on noise transfer matrix analysis. A pyramid structure and a weight learning module are adopted to improve the detection rate and reduce the false positive rate. In total, 80 videos were examined through delicate anti-forensic forgery operations to verify the detection performance of the proposed method and three previously reported methods against anti-forensic forgery operations. In addition, two of the latest learning-based methods were included in our experiments to evaluate the proposed method. The experimental results show that the proposed method significantly improves the detection of frame deletion points compared with traditional and learning-based methods, especially in low false positive rate (FPR) intervals, which is meaningful in forensic science.

Monitoring of vegetation changes based on RS monitoring in Changbai Mountain Nature Reserve

High vegetation cover helps maintain the ecosystem's stability and reduces the risk of soil erosion and natural disasters. Vegetation restoration is essential for the ecological value of Changbai Mountain Nature Reserve. In this study, the interannual changes in vegetation cover in Changbai Mountain Nature Reserve, China, from 2013 to 2022 were studied in depth based on Landsat remote sensing data and land use transfer matrix. The study includes interannual dynamic changes in vegetation types, quantitative analysis of interannual changes in surface vegetation types, and the land use transfer matrix analysis. In addition, the drivers of dynamic changes in vegetation types were analysed. The research indicates a notable advancement in ecological restoration within Changbai Mountain Nature Reserve between 2013 and 2022. There was a substantial reduction in the extent of barren land, which predominantly transitioned into grass and woodland areas. In particular, the year 2022 exhibited a significant increase in grassland area when compared to 2013, with a remarkable expansion of 27.18 square kilometers, primarily concentrated in the central-eastern sector of the study area. The findings of this investigation serve as a valuable scientific foundation for guiding ecological preservation and management decisions within Changbai Mountain Nature Reserve, contributing to a deeper comprehension of the evolving patterns in vegetation cover.

Exploring the impacts of land use and land cover change on ecosystem services in Dongting Lake, China: a spatial and temporal analysis

Background and objectives: Land use and land cover change (LULCC) directly affects the human living environment and economic society by influencing ecosystem services. This study explores the complex relationship between LULCC and ecosystem services in the Dongting Lake region of China.Methods: The analysis incorporates the transfer matrix analysis of LULCC, ecosystem service value (ESV) accounting, Mann–Kendall mutation test, gray correlation, and path analysis. This study explored the spatial and temporal characteristics of LULCC and ecosystem services and revealed the comprehensive impacts of LULCC on ecosystem services from the perspective of factor interactions.Findings: The findings reveal that open water (OW) area and farmable land are the dominant land use types transferring in and out of the study area, with significant interconversion observed among open water area, wetland (WL), arable land (AL), and forest land (FL). Water conservation, waste disposal, climate regulation, and biodiversity conservation emerge as the most crucial ecosystem services in the study area. The study identifies consistent patterns of abrupt changes in LULCC and ESV across six analyzed time periods. Forest land exhibits the most substantial direct influence on climate regulation, gas exchange, soil formation and protection, conservation of biodiversity, raw materials, and recreation and leisure. Additionally, forest land, wetland, arable land, and open water area contribute significantly to the total ESV, with forest land being the dominant factor influencing the spatial differentiation of ecosystem services in the Dongting Lake region.Conclusion: The research reveals the consistency of ecosystem services and LULCC trends in the Dongting Lake area. LULCC is a complex process influenced by multiple factors, in which the conversion between ecological and non-ecological land use has a significant impact, and the complex coupling and coordination among LULCC drivers together influence ecosystem services. Furthermore, LULCC alters the structure and scale of ecosystems, resulting in alterations in the ESV.

An open-source alignment method for multichannel infinite-conjugate microscopes using a ray transfer matrix analysis model.

Multichannel, infinite-conjugate optical systems easily allow implementation of multiple image paths and imaging modes into a single microscope. Traditional optical alignment methods which rely on additional hardware are not always simple to implement, particularly in compact open-source microscope designs. We present here an alignment algorithm and process to position the lenses and cameras in a microscope using only image magnification measurements. We show that the resulting positioning accuracy is comparable to the axial resolution of the microscope. Ray transfer matrix analysis is used to model the imaging paths when the optics are both correctly and incorrectly aligned. This is used to derive the corresponding image magnifications. We can then extract information about the lens positions using simple image-based measurements to determine whether there is misalignment of the objective lens to sample distance (working distance) and with what magnitude and direction the objective lens needs to be adjusted. Using the M4All open-source 3D printable microscope system in combination with the OpenFlexure microscope, we validate the alignment method and highlight its usability. We provide the model and an example implementation of the algorithm as an open-source Jupyter Notebook. This article is part of the Theo Murphy meeting issue 'Open, reproducible hardware for microscopy'.

Spatio-Temporal Changes and Habitats of Rare and Endangered Species in Yunnan Province Based on MaxEnt Model

Biodiversity is crucial for ecosystem functioning, but it is rapidly declining due to human activities and climate change. Protecting biodiversity has become a key priority for global environmental conservation actions. Rare and endangered species have a great impact on the ecosystem, yet due to their limited survival capacity, they are more prone to extinction, thus exerting a significant impact on biodiversity. However, current research reveals a lack of information concerning the potential distribution and changes of these species. This study used the maximum entropy model to predict the present and future potential habitats of rare and endangered species in Yunnan Province. After superimposing model results, four richness regions are divided by the natural breakpoint method and analyzed. Existing protected areas are compared with hotspots, and the land-use composition of hotspots is also analyzed. The results revealed that, in both current and future scenarios, rare and endangered species in Yunnan Province are primarily found in the western mountainous region, the Xishuangbanna–Wenshan high temperature area, and the Kunming–Qujing dense vegetation cover area. These species are also expanding their distribution towards the western mountainous area. However, under the low carbon emission scenario (RCP2.6), these species will spread from the high abundance regions to the low altitude hotspots by 2070. In the high carbon emissions scenario (RCP8.5), there will be fewer high abundance areas in 2070 than in 2050. The transfer matrix analysis reveals regional richness variations over time. Furthermore, the analysis revealed significant conservation gaps and found that existing hotspot areas were heavily affected by human activities. To improve conservation efficiency, it is necessary to enhance the protection of existing hotspots in Yunnan Province. Climate change plays a significant role in species migration, with precipitation levels being a key factor. The necessary actions should be taken to address the insufficient protection, resolve conflicts between human activities and land use in critical areas, and formulate effective strategies for adapting to future climate changes. Yunnan Province, with its rich species resources, has the potential to become a global innovator in biodiversity conservation by implementing improved conservation strategies.

Transfer matrix analysis of the birefringent fiber Fabry–Perot cavity and laser frequency locking

The Fiber Fabry–Perot (FFP) cavities are reported as various types of sensors in conventional experiments while rarely reported in application of frequency stabilization. We fabricated 10 cm, 30 cm, 50 cm Single Mode Fiber Fabry–Perot (SMF-FP) cavity with parallel end faces to serve as a frequency reference. The thermoelectric cooler (TEC) and piezoelectric transducer (PZT) are configured on the cavity structure for frequency coarse tuning and fine tuning. By establishing the transfer matrix model of light resonant process in the SMF-FP, the birefringence and thermal effect of resonance peak is explained, and the relationship between the locking error signal and the input polarization is analyzed. It provides a method to improve the precision and stability of frequency locking by optimizing the input polarization performance. Finally, The Allan variance after the frequency locking reached 2.8×10−10 at 10s of the integral time, which is higher half an order magnitude than the stability of free running. The research work is of great significance to the compact frequency reference with low cost and high precision.

Prediction and Evolution of Carbon Storage of Terrestrial Ecosystems in the Qinling Mountains North Slope Region, China

The Qinling Mountains north slope region constitutes a vital terrestrial ecosystem reserve within China. This study employs land use and land cover (LULC) data spanning from 1990 to 2020. Utilizing methodologies encompassing land use classification, transfer matrix analysis, and the application of the PLUS and InVEST models, this research endeavors to elucidate the spatial-temporal dynamics of land use patterns and associated carbon storage in the region. These analyses are conducted within the context of four prospective scenarios: Natural Development Priority, Arable Land Protection Priority, Ecological Protection Priority, and Urban Development Priority, all projected onto the landscape for 2030. Notably, our findings reveal a consistent decline in carbon storage across all four scenarios for 2030 compared to the baseline year 2020. This stark reality presents substantial challenges to achieving the region’s targets of carbon peaking and eventual carbon neutrality. Furthermore, this paper meticulously delineates six key drivers contributing to this decline in carbon storage. In conclusion, it proffers nine strategic recommendations aimed at augmenting carbon storage, with an overarching objective of establishing a harmonized mechanism capable of balancing urban development, safeguarding cultivated land, fortifying ecological preservation, and enhancing carbon sequestration within the area.

Electro-mechanical transfer matrix modeling of piezoelectric actuators and application for elliptical flexure amplifiers

Mechanically amplified piezoelectric actuators (APAs) can be found in many scenarios of precision engineering and instrumental devices. However, the electro-mechanical design of curvilinear APAs is difficult due to the existence of curved flexure beams and multi-domain electro-elasto dynamics. In this paper, the electro-mechanical behavior of elliptical APAs is studied by exploiting a novel electro-mechanical transfer matrix method. The motivation is to facilitate both the static and dynamic analyses of such a complex APA with curvilinear flexure beams by considering the multi-domain dynamics of piezoelectric stacks and compliant mechanisms from an electro-mechanical viewpoint. To this end, an analytical electro-elasto transfer matrix of piezoelectric stacks operating at the d33 mode is derived in the form of Taylor's series based on Timoshenko beam theory. The dynamic response spectrum of displacement and impedance for elliptical APAs are insightfully captured by such an electro-mechanical model. Different topologies of elliptical APAs are also compared and the optimal configuration is suggested. At last, a proof-of-concept prototype is fabricated and tested with a special focus on experimental evaluation of the electro-mechanical coupling model.

Sensitivity analysis and noise reduction optimization design of the insert-pipe double expansion chamber muffler

The insert-pipe double expansion chamber muffler has less passbands and higher sound attenuation in the plane wave range, which is widely used to reduce noise of industrial equipment. But there are many parameters that affect the transmission loss of the insert-pipe double expansion chamber muffler, and the sensitivity of each factor is not clear. Identifying the most influential factor among numerous parameters is an important challenge. It is necessary to investigate the sensitivity of all parameters and study parameter optimization algorithms. Based on the method of transfer matrix analysis, this paper studies the insert-pipe double expansion chamber muffler and its sound elimination mechanism. The global sensitivity analysis of the transmission loss of insert-pipe double expansion chamber muffler was conducted using Sobol's method, and the influence of each parameter sensitivity was examined. According to the noise characteristics of an air conditioner compressor, the external penalty function method (EPFM) algorithm is used to optimize the insert-pipe double expansion chamber muffler, and the maximum transmission loss is obtained in a specific frequency band. According to the optimized parameters, the muffler is designed, manufactured, and installed in a pipeline system to carry out a noise experiment to verify the effectiveness of the optimization scheme.

Increasing NH3 Emissions in High Emission Seasons and Its Spatiotemporal Evolution Characteristics during 1850–2060

Ammonia (NH3) is a crucial alkaline component in the atmosphere, with significant impacts on environmental and ecosystem health. However, our understanding of the long-term variability characteristics of NH3 emissions is still limited due to the scarcity of long-term continuous NH3 emission observation data. In this study, we investigated the global NH3 emission evolution pattern during the high-emission season (March–August) in historical (1850–2014) and future (2015–2060) periods, based on the simulated global NH3 emission and temperature data using the CESM2-WACCM model from CMIP6. We utilized cluster analysis, KNN regression simulation, and transfer matrix analysis to explore the emission characteristics. In the historical period, the analysis revealed that the high NH3 emission season is March–August, accounting for about 60% of annual emissions, with a significant increasing trend of NH3 emissions. The global average NH3 emissions in the last 164 years were about four times higher (28.06 mg m−2) than those in 1850 (5.52 mg m−2). Moreover, on the intercontinental scale, NH3 emissions from 1850 to 2014 March–August exhibited dynamic increases characterized differently across continents. Europe showed an increasing and then decreasing trend, Asia demonstrated a rapid increase, while South America, North America, and Africa exhibited medium increases, and Australia showed low increases. The global NH3 emissions experienced three distinct periods of low (1850–1964, slope = 0.059 mg m−2 y−1), high (1965–1988, slope = 0.389 mg m−2 y−1), and medium (1989–2014, slope = 0.180 mg m−2 y−1) rates of increase. Starting from the high rate of increase period, the hotspots of global NH3 emissions gradually shifted from Europe to East and South Asia. Looking ahead, our findings suggest that the global NH3 emission rate will tend to slow down under the Representative Concentration Pathway (RCP) 4.5 and RCP8.5 warming scenarios. However, compared with the medium-rate increasing period, the moderate and heavy NH3 emission areas under RCP4.5 and RCP8.5 scenarios will show a tendency to expand by 2060, with the proportion of area covered by heavy emissions increasing by 0.55% and 0.56%, respectively. In conclusion, our study highlights that NH3 pollution remains a significant environmental challenge in the future period, with Asia and Europe being the key areas requiring attention for NH3 emission reduction.

Current and future characteristics of land use based on intensity analysis and PLUS model : a case study of Foshan city, China

Land use change drives urban pattern change. The development of urbanization will result in the diminution of ecological land and the extinction of ecological defense. Foshan is a highly typical city. Identifying the characteristics of dynamic land use changes and predicting the future land use pattern are crucial components of land use planning. Land use transfer matrix and intensity analysis model were utilized in this study. Three representative years, 2010, 2015, and 2020, were used to analyze the interval, category, and transition level characteristics for Foshan City. Then, based on the PLUS model and the Markov model, multiple scenarios for the land use of Foshan City in 2030 were developed. The results indicate the following: (i) According to the interval level intensity analysis, the general trend of land use intensity between 2010 and 2020 is first rapid and then gradual. At the category level, construction land demonstrates stable activity with increasing intensity, whereas dike-ponds demonstrate continuous activity with decreasing intensity. (ii) From 2020 to 2030, there is a slowing in the intensity of site conversion. The natural development scenario is more in line with the city's development. (iii) In simulations of future urban scenarios, the dike-pond has a decreasing trend over the scenario. At the future transition level, three possible land use conversion systems exist: "forestland—dike-pond," "water—dike-pond," and "dike-pond—construction land." With this study, Foshan City can serve as a case study for sustainable development and rational planning.Article HighlightsLand use change components, quantity, exchange and shift were estimated.The largest net change occurred in 2010–2015 due to human activities.Spatial reallocation were characterized by exchange and shift.The largest exchange occurred in 2010–2020 due to the dike-pond eroded.The dike-pond has a decreasing trend over the simulated scenario.

Lithography-free near-infrared broadband absorber based on a multilayer nanosystem

Broadband absorber has been intensively researched for decades because of its high absorption property which can be applied to various applications. Most designed absorbers are based on metasurfaces with complex surface-patterns and complicate manufacturing processes. In this paper, we propose a lithography-free, simple four-layer dielectric and metal nanosystem as a broadband absorber. The performance of the absorber is demonstrated by both numerical finite difference time domain (FDTD) method and analytical transfer matrix method (TMM). In the concerned wavelength range from 800 nm to 2300 nm, the average absorption is 95.81%. And the two maxima of absorptions are 99.99% at 970 nm and 99.31% at 1708 nm. The broadband absorption is due to the ohmic loss of the material Cr, the reflection of the Al layer, the destructive interference between the Cr and the Al layers, and the top Al2O3 helping much light to enter the absorber. And the simple multilayer absorber does not require precious metals, lithography processes, making a large-scale, low-cost manufacturing process possible.

Impact of watershed habitat quality based on land use: a case study of taking Ciyao River Basin

Land use pattern is one of the most important factors affecting the quality of habitats, which is taken as the research objective in this study. Based on the land use data of Ciyao river basin from 1985 to 2020, transfer matrix analysis, superposition analysis, and zoning statistics were carried out by ArcGIS. The impact of main threat sources (cultivated land, urban land, and rural residential land) on water quality was calculated using the investment model. The habitat changes and the impact of the habitat quality of the basin on the hydrological and water quality were analyzed. The findings demonstrated that the land-type conversion in Ciyao River Basin from 1985 to 2020 is mainly manifested in the conversion from cultivated land to construction land (94.49 km2), and from grassland to cultivated land (21.59 km2) and forest land (27.15 km2). The habitat quality of the Ciyao River Basin decreased gradually from North to South. The medium and high habitat quality areas are mainly concentrated in the headwater area of the river. Due to the change in land type, the habitat quality in the headwater area of the river significantly improved from 2005 to 2020, while the habitat quality in the confluence area of the Wuliang section significantly declined from 1995 to 2015. Due to the improvements of habitat quality in the source area of the river and water conservation capacity, the total amount of water resources and annual runoff depth of Ciyao River significantly increased from 2005 to 2019 without significant changes in precipitation. The water quality of the Ciyao River has improved due to development of environmental pollution control and the improvement of watershed habitat in 2016–2020.

祁连山国家公园植被时空变化及其对人类活动的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 祁连山国家公园植被时空变化及其对人类活动的响应 DOI: 10.5846/stxb202107221990 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 甘肃省创新群体项目（20JR10RA038）；中国科学院"西部之光"交叉团队项目-重点实验室合作研究专项；国家重点研发计划项目（2019YFC0507401） Spatial and temporal changes in vegetation cover and response to human activities in Qilian Mountain National Park Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:祁连山国家公园地处青藏、蒙新、黄土三大高原交汇地带的祁连山北麓，作为国家公园体制试点之一，是我国重要的生态功能区、水源涵养地和生物多样性保护优先区域，其生态功能不可忽视。以祁连山国家公园2000-2019年归一化植被指数（NDVI）和净初级生产力（NPP）数据为基础，结合气温、降水、土地利用、矿产开采和旅游发展数据，利用泰尔-森趋势分析（Theil-Sen趋势分析）、曼-肯德尔检验（Mann-Kendall显著性检验）、土地转移概率矩阵和多元残差分析方法，分析该区域的植被时空分布特征、变化趋势特征及其对气候变化和人类活动的响应。结果表明：（1）2000-2019年祁连山国家公园内NDVI和NPP在空间上呈现出东南高西北低，由东南向西北递减的格局。时间上呈现上升趋势，上升速率分别为0.0053/a和0.0014/a；（2）祁连山国家公园内NPP提高、降低和稳定区域分别占总面积的87.29%、0.40%和12.30%。降低区域零星分布于整个国家公园，其中在走廊南山和冷龙岭交汇处，靠近甘青两省交界边缘分布最为集中。提高区域分布广泛，尤其以国家公园东部最为明显；（3）祁连山国家公园NDVI与气温呈现显著正相关区域约占40.18%，与降水呈现正相关区域约占25.70%，气温上升、降水增多促进了国家公园植被生长，适宜的水热组合对植被生长更有利；（4）人类活动对植被变化的影响具有两面性：约有28.91%矿业、旅游和水电站在整改、规范之后植被生长状况仍较差，生态环境没有明显恢复；退耕还林还草工程、生态林建设工程成效显著，近3年林地、草地面积增多。（5）祁连山国家公园大部分植被覆盖变化是由气候变化和人类活动共同导致。 Abstract:Qilian Mountain National Park is located in the north piedmont of Qilian Mountains at the intersection of Qinghai-Tibet, Mongolian-Xinjiang and Loess. As one of the national park system pilots, Qilian Mountain National park is an important ecological function area, a water retention area and a priority area for biodiversity conservation in China, and its ecological functions cannot be ignored. Based on the Normalized Difference Vegetation Index (NDVI) and Net Primary Productivity (NPP) of Qilian Mountain National Park from 2000-2019, combined with temperature, precipitation, land use, mineral extraction and tourism development data, we used the Theil-Sen slope estimation, Mann-Kendall test, land transfer matrix and multivariate residual analysis methods to analyze the spatial and temporal distribution characteristics of vegetation, change trend characteristics and its response to climate change and human activities. The results showed that (1) NDVI and NPP in Qilian Mountain National Park from 2000 to 2019 showed a spatial pattern of high in the southeast and low in the northwest, decreasing from southeast to northwest. Temporally, they showed an increasing trend, with an increase rate of 0.0053/a and 0.0014/a, respectively. (2) The improved, decreased and stable areas of NPP in Qilian Mountain National Park accounted for 87.29%, 0.40% and 12.30% of the total area, respectively. Decreased areas are scattered throughout the national park, with the most concentrated distribution at the intersection of Zoulang South Mountains and Lenglongling, near the border edge of Gansu and Qinghai provinces. The improved areas are widely distributed, especially the most obvious in the eastern part of the national park. (3) The NDVI of Qilian Mountain National Park shows a significant positive correlation with temperature in about 40.18% of the area, and a positive correlation with precipitation in about 25.70% of the area, the increase in temperature and precipitation promotes the growth of vegetation in the national park, and a suitable combination of hydrothermal conditions is more favorable to the growth of vegetation.(4) The impact of human activities on vegetation changes was two-sided:Approximately 28.91% of mining, tourism and hydroelectric power stations in the national park still had poor vegetation growth after rectification and regulation, and the ecological environment has not recovered significantly; The cropland to forest and grassland conversion projects and ecological forest projects have been effective, the area of forest and grassland has increased, in the past three years.(5) Most of the vegetation cover changes in Qilian Mountain National Park were caused by a combination of climate change and human activity. 参考文献 相似文献 引证文献