Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： As an important energy production and supply base in China, Xinjiang plays a pivotal role in the deli#2;cate balance between economic development and carbon emissions. Ensuring a harmonious coordination between these factors is essential to achieve sustainable economic growth and meet goals related to energy conservation and emission reduction. This paper measures and analyzes the spatiotemporal characteristics of energy consumption carbon emissions in Xinjiang from 2000 to 2020 using spatial autocorrelation based on the data obtained from Xinjiang Statistical Yearbook. Results indicate that the total carbon emission intensity from energy consump#2;tion in Xinjiang shows an increasing trend every year during the study period. Nevertheless, the overall trend reveals a reduction in the intensity of carbon emissions. The spatial distribution of carbon emission intensity shows that the eastern slope of Tianshan Mountain has a high carbon emission intensity, whereas the northern edge of Junggar, the northern slope of Tianshan Mountain, and the northern slope of Kunlun Mountain has a low carbon emission intensity. These regions exhibit evident clustering characteristics. Considering global warming and carbon emission reduction, Xinjiang must work toward achieving the goals of“carbon peak and“carbon neutrality”while promoting high-quality socioeconomic development in the area through the implementation of a multienergy, complementary green energy network
Subjects: Geosciences >> Geography submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： Abstract：The changes in soil loss, runoff, and sediment load in the headwaters of the Yangtze River and their correlation were studied based on the data of daily precipitation at 12 stations, and annual runoff and sediment at Zhimenda station in the headwaters of this river from 1980 to 2020. (1) The annual soil erosion modulus in the source area showed a significantly increasing trend (P<0.05), and the average annual soil erosion modulus was 4.71 t·hm-2·a-1. The erosion intensity and higher grades of erosion were mainly distributed in the southeast of the headwaters of the Yangtze River. (2) The runoff increased significantly (P<0.05), however, there was an abrupt change in 2004 when the suspended sediment concentrate and sediment load showed no significant change. (3) Precipitation had a significant positive effect on runoff and soil loss at 70% and 52.9%, respectively. Both runoff and soil loss showed direct positive effects on the sediment load. Precipitation, runoff, and soil loss explained 72.5% of the variation in sediment load. During this period, changes in precipitation had significant effects on soil loss and sediment in the headwaters of the Yangtze River. The results can provide a scientific basis for the research and evaluation of the effects of implementing ecological engineering in the headwaters of the Yangtze River.
Subjects: Geosciences >> Geography submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： The Wuding River Basin is the key area for the implementation of the grain for green program on the Loess Plateau. Exploring the spatial differentiation mechanism of land cover and the characteristics of variation of related water-carbon variables is essential for supporting water and soil resources conservation and planning, along with serving the construction of regional ecological civilization. Here we used the linear tendency method, Mann-Kendall trend test, Pettitt test, and geodetector to analyze the spatiotemporal characteristics and the factors driving the spatial differentiation of land cover in Wudinghe River Basin. In addition, from the perspective of land- water- carbon coupling, we analyzed the characteristics of variation of total primary productivity (GPP), actual evapotranspiration (ET), and water use efficiency (WUE). Three main results were as follows: (i) The total grassland, forest, and construction land increased significantly, while the cropland and barren land decreased significantly during 1990-2019. The area of forest and grassland increased mainly in the lower reaches of the basin and along Wuding River. (ii) Population density, precipitation, and temperature have a significant impact on the spatial pattern of land cover. On the whole, the influence of socioeconomic factors is greater than that of natural factors, but the influence of natural factors represented by precipitation and temperature is increasing. (iii) There is a good correlation between the variation of water- carbon variables and land cover change. Spatially, GPP, ET, and WUE are relatively high in the southeastern part of the basin where cropland, forest, and grassland are the main cover, while they are lower in the northwestern part of the basin where grassland and barren land are the main cover. In terms of time, GPP, ET, and WUE all showed increasing trends during 2001-2019. GPP and WUE increased significantly in most parts of the basin, while ET increased significantly mainly in its middle and lower reaches. In conclusion, under the implementation of the grain for green program and climate change, the forest and grass in Wudinghe River Basin have been restored and the ecology has been improved.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-03-15 Cooperative journals: 《干旱区地理》
Abstract： As the main carrier of alpine freshwater ecosystems, alpine lakes are currently experiencing rapid climate change that has profound and complex effects on their ecosystems. In this study, we systematically analyze the effects of altitude-dependent warming on the thermal properties, dissolved oxygen stratification, and biological processes of alpine lakes in the context of climate change, describe the adaptation measures of alpine aquatic organisms and changes in underwater radiation characteristics in the context of radiation enhancement, and reveal the effects of precipitation changes on the cross-ecosystem material subsidies and biogeochemical cycles in alpine lakes, as well as the mechanism of the impact of precipitation changes on these cross-ecosystem material subsidies and biogeochemical cycles in mountain lakes. In the future research, we must improve the integrated response experiments of lake habitats under the changes of multiple climate factors, strengthen the systematic monitoring and integration of the whole elements of alpine lake ecosystems, and change the research type (i.e., static and qualitative research to process, dynamic, and quantitative research) to enhance knowledge on the response mechanism of alpine lake ecosystems to global climate change.
Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》
Abstract： In arid areas，snowmelt is the main source of water resource formation. Therefore, the formation, transformation and utilization of snow resources are important research topics on the development and utilization of water resources in Xinjiang, China. Further, hydrological model is a key to determine the formation and transformation of water resources. This study uses the field experimental area of Tianshan Snow Station, Chinese Academy of Sciences, as the experimental area. The meteorological data and snowmelt amount were adopted as the independent and dependent variables. A snowmelt model based on temperature change is studied, and a singlefactor simple model is calibrated and validated. Simultaneously, the variation law of snowmelt in the experimental area for many years and the response process of snowmelt to temperature are analyzed. The results indicate that snowmelt still occurs in winter in certain low- temperature ranges. In the study area of Tianshan Mountains, the critical value of daily average temperature of snowmelt is approximately -7 ℃. When the temperature is lower than -7 ℃, snowmelt is basically suspended, reflecting the characteristics of snowmelt in arid areas. In terms of the model, a single factor simple snowmelt model based on temperature exhibits good performance in simulating snowmelt in mountainous areas. During the calibration period (2016—2020), the correlation parameters of Bias, MAE, RMSE, NSE and R2 between the observed and simulated snowmelt values were -0.037, 0.367, 0.482, 0.870, and 0.876 respectively. The values of validation period were -0.210, 0.292, 0.577, 0.845, and 0.811, respectively. The simulation results and correlation coefficients during the validation period indicate that the simulated value of the model has good consistency with the measured value. The advantage is that the amount of snowmelt in the basin can be estimated through the available meteorological data. The results provide a relatively simple algorithm for snowmelt calculation in arid areas and a simple and effective snowmelt submodule for a hydrological model. This study has an important reference value for understanding the change law of snowmelt and the simulation and prediction of snowmelt runoff in subsequent studies
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：针对风云三号C星微波湿温探测仪(FY-3C/MWHTS)的陆地晴空观测资料，建立了一维变分反演系统，对大气的温湿廓线进行反演。为了更好的描述温湿廓线的相关性，同时减小温度和湿度在反演过程中相互之间的误差传递，提出了使用背景协方差矩阵的联合矩阵和单独矩阵进行组合反演的方法。对于MWHTS模拟亮温和观测亮温之间的偏差，使用逐扫描点的统计回归方法进行校正。选择我国部分陆地区域的晴空观测亮温进行温湿廓线的反演，并利用欧洲中期天气预报中心(ECMWF)再分析数据、美国国家环境预报中心(NCEP)分析数据以及无线电探空观测(RAOB)数据对反演结果进行验证，温湿廓线的反演结果与ECMWF再分析数据验证的最大均方根误差分别是2.59 K和11.87%，与NCEP分析数据验证的最大均方根误差分别是1.88 K和21.50%，与RAOB数据验证的最大均方根误差分别是3.43 K和25.48%，验证结果表明了反演结果的可靠性。另外与国外同类载荷AMSU观测亮温的物理方法和统计方法反演精度进行了对比，结果表明：MWHTS具有较强的湿度廓线以及高空温度廓线的探测能力，且针对MWHTS的观测亮温建立的一维变分反演系统具有较高的反演精度。与NCEP 6小时预报廓线的验证结果表明：反演的湿度廓线可以提高预报廓线的精度。
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：提出了一种单层的具有多谐振结构的微带反射阵单元,利用HFSS对其反射相位特性进行仿真分析，获得了约430°的反射相位动态范围，并且反射相位曲线的线性度较好。根据此单元设计了一个工作在Ku波段的微带反射阵，用指数渐变槽线（Vivaldi）天线作为该反射阵的馈源。仿真结果表明，在中心频率处增益可达27.1dB，半功率波瓣宽度均为4.96°，在12GHz-15.5GHz的频带内增益波动约2dB，具有较宽的频带。将此Vivaldi天线和反射阵天线进行加工测试，得到的测试结果与仿真结果吻合的较好。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：该文提出一种新型的具有多谐振结构的单层微带反射阵单元，是由六个振子以一定的间隔平行放置组合而成，该单元具有良好的线极化特性，采用高频电磁仿真软件HFSS对单元的各个参数进行优化分析，使得单元的反射相位曲线在两个频段内均具有良好的线性度。根据此单元设计了一个工作在X/Ku波段的偏馈双频双极化微带反射阵天线，在两个频段内采用同一个角锥喇叭天线作为其馈源。将此反射阵天线进行加工并测试，测试结果表明，在X波段中心频率10GHz和Ku波段中心频率13.58GHz处，天线均具有良好的辐射性能。实测和仿真结果吻合的较好，证明了该反射阵天线具有良好的双频辐射性能。该文的设计对于微带反射阵列天线实现双频双极化性能来说具有重要的参考价值。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：本文基于灵敏型地基相干高频雷达（AgileDARN）系统，回顾了空间电离层探测的研究背 景，简要介绍了 AgileDARN 雷达系统。对其数字信号处理系统进行了分析，阐述了系统发射信号产生 模块、回波信号处理模块的工作流程，设计数字系统的硬件结构，详细分析了系统发射信号多脉冲序 列产生的机制，回波信号处理的详细步骤，利用 FPGA 实现原始信号的产生，阵列天线信号波束合成 处理，以及系统中数字滤波器的设计，并通过仿真实验验证了 FPGA 设计的可行性和有效性，满足了 AgileDARN 雷达数字系统的设计要求。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：太阳跟踪研究的发展，向太阳跟踪器的控制系统智能化提出了更高的要求。以SOLYS Gear Drive 太阳跟踪器为仪器平台，创新性地提出利用路由器建立控制主机和太阳跟踪器在局域网内，以及局域网和互联网之间的通信,并以虚拟仪器开发软件LabVIEW为软件平台，综合调用百度地图应用程序接口API和指令脚本文件，设计了一套控制系统。实现对仪器的状态监测，指令控制，远程访问等。系统功能丰富，操作简单，界面可视化好，普遍适用性强。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：AgileDARN雷达系统是一种基于全数字相控阵技术的灵敏型地干高频雷达系统，实现对中高纬度电离层的探测。本文对雷达系统的数字信号处理展开研究，设计分析雷达系统收发信号处理流程 ，基于FPGA芯片实现信号收发 、 幅相不一致性校正、数字滤波 、数字波束合成处理，实现方向图的灵活扫描和定向精度的提升，通过仿真实验证了FPGA设计的可行性和有效性。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In order to ensure quantum science experiments can be developed smoothly, a high data rate two-way link for Space-Ground microwave communication must be established. Via following the study on Consultative Committee for Space Data Systems (CCSDS) and taking into account the scientific requirements of microwave communication link for quantum science experiment satellite, the physical layer hardware architecture and modulation/demodulation algorithm of microwave communication link for the satellite are presented.The uplink modulation type of the microwave communication link is SRRC-OQPSK, which accord with CCSDS spectrum standard. The specification of uplink data rate is 1.024Mbps,. The downlink modulation type of the microwave communication link is SRRC-OQPSK/GMSK, and the data rate is 4Mbps. By compatible tests with several ground stations, we find that the sensitivity of carrier acquisition is superior to -100dBm, and AGC ability is greater than 43dB. Moreover, the bit error rate of actual transmission is superior to 1�0-9 as the received signal level is equal to -96 dBm. The measured results indicate that the physical layer design scheme of microwave communication link meets the requirements of space quantum science experiments.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Multi-point synchronous magnetic field measurements can give more accurate space current density compared with the traditional single-point measurement, since multi-point measurement can eliminate the temporal change in the magnetic field. Based on the current density inversion method for multi-point magnetic field measurements, through simulation, several factors affecting space current density inversion are analyzed, such as the number of satellites, satellite formation configuration, satellite positioning precision, satellite attitude determination error, magnetic field measurement accuracy, external magnetic field intensity, external current density and so on. It is shown that 5-point measurements are better than 4-point measurements, and error in attitude determination and external magnetic field intensity are the main factors causing the error in current density inverted, while satellite formation configuration is also an important factor. According to the simulation, the maximum error in current density is less than 24% near the equator when the attitude determination error is 0.001癮nd the scale of the satellite formation is about 100km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： By studying Rayleigh lidar data，The seasonal variations of atmospheric temperature of 35-70km in Beijing area are analyzed.The atmospheric temperature between 30-70km height range at Beijing region has obvious annual cycle variation. The highest temperature in the stratosphere appeared in June and July, which is about 270K. The lowest temperature in the middle layer 70km is also in June, July, about 200K. Take the data of October 14, 2014 as an example， Gravity wave dissipation under 50km is found，while， the gravity waves propagate upward almost without dissipation above 50km.By comparing the average potential energy density between 35-50km height range, the seasonal variation of the gravity waves activities intensity in the Beijing area was studied. The gravity waves activities over Beijing have an obvious cycle of one year.The average potential energy density in winter is , while in summer, the average potential energy density is , the gravity waves activities intensity in winter is about two times of that in summer. In addition, the profile of seasonal averaged gravity waves potential energy density are given in spring,summer,autumn and winter. The dissipation of gravity waves in different seasons and different heights is analyzed in Beijing area.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Parameterized ionosphere model TIEGCM is used as background model. Basing on the COSMIC observations, global ionospheric electron density assimilation model is established using ensemble Kalman filter. Result shows, this model can effectively assimilate observations into background model and acquire three dimensional ionospheric electron density. Compared to background, the error between analysis and observations decreases significantly. The root mean square error(RMSE) of NmF2 decreases about 60% for observations assimilated, and 20% for observations not assimilated. The RMSE of hmF2 doesn’t get improvement except for mean error. The results of simultaneous assimilation (SA) and batches assimilation (BA) are compared for this case. The time that the two methods spend in assimilation is about 6 to 7 minutes, which does not differ very much. SA needs nearly 8 GB storage while BA less than 2GB. The statistic of electron density error shows that they nearly acquire the same mean error, but the SA gets relative better improvement in RMSE above 250km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： Springs can be used to provide release rate for payload in space missions. In order to guarantee the precise releasing velocity of payload and the minimum mass of springs,a nonlinear constrained optimization model was built with geometric constraints, reliability and stability. The theory solution of MATLAB was brought into Adams for simulation, which can work out the fitting relationship between theory and simulation. The spring design parameters were obtained by using the fitting relationship and calculation of MATLAB. The result was verified by Virtual Prototype Technology and perfect performance of design parameters was achieved.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： This paper discussed in detail the relation between the inflation impact load bearing capability and the structural sensitive parameter. Starting from solving tight-coupling characteristics of inflation impact load,and using the computational modeling and numerical simulation method, the model of coupling analysis between the structure and impact airflow was built. By adjusting structural parameters, the response of the canopy structure was analyzed and compared. The simulation result shows that the weak parts of ring slot parachute include the vicinity of radial reinforcing bands,the connection between the canopy and rope and the neighboring region of the top hole. Strengthening measures and the relation between structural sensitive parameters and load bearing capability were discussed accordingly. Research in the paper proves the validity of the simulation method for structural design. Conclusions provide the solid basis for the optimization design.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-04
Abstract： Two-dimensional coupled optics swing mirror is a core module in an infrared optical scanning system of space, which demands special requirements of high precision and decoupling movement in a servo control system. A novel decoupling strategy called coupled offset compensation and segmentation stepping method was proposed based on accurate system modeling, abundant simulating and analysis results. The proposed servo control system of optics swing mirror was mainly constructed with a DSP chip, high precision brushless resolvers and limited angle brushless torque motors, which adopted position feedback and velocity feedback by PID algorithm. The experimental results indicate that the novel decoupling strategies are correct and that the servo control system makes the swing mirror achieve high precision movement which has a good dynamic characteristics, short response time and small overshoot. The method applied to the servo control system can be widely used in the field of high-precision swing scanning control system and possesses a great application prospect.
Peer Review Status:Awaiting Review
Hits
Hits
Downloads
Comment