Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Land use/cover change will interfere with the stable supply capacity of ecosystems, which in turn poses a threat to ecosystem services and sustainable development. Taking Urumqi City of Xinjiang, China, as the study area, this study simulates land use changes in Urumqi City under multiple scenarios in 2030 based on the patch- generating land use simulation (PLUS) model and combines the equivalent factor method and spatial autocorrelation analysis to estimate and project the ecosystem service value (ESV) and its trade-off synergy for 1990—2030 in Urumqi City. The results are as follows: (1) Land use in Urumqi City shows a trend of“two increases and four decreases”from 1990 to 2020. In the integrated development scenario, the area of built- up land increases, while the area of ecological land is also on the rise; in the key development scenario, the expansion of urban built-up land is the most drastic, and the area of arable land is severely degraded. (2) From 1990 to 2020, the trend of ESV in Urumqi City has a“V”shape. In 2030, ESV increases under the ecological protection scenario and the comprehensive development scenario and decreases under the inertia development scenario and the key development scenario. (3) Under the four development scenarios in 2030, the synergistic relationships among various ecosystem services in Urumqi City are primarily synergistic, with“high-high”and “low-low”synergistic aggregation areas coinciding highly with the distribution of high and low ESV values, and trade-off relationships sporadically distributed in local areas. These findings may serve as a basis for distributing ESVs in Urumqi City and can also provide scientific reference for the spatial planning of Urumqi City and the construction of ecological security patterns.
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： The coordination development of land ports and port-counties is a key component of developing port economic belts with high quality. Using the entropy weight method and coupling coordination model, we analyze the spatiotemporal characteristics of the coupling coordination development of Xinjiang land ports and portcounties in China from 2009 to 2019. The findings are as follows: (1) The overall development of Xinjiang land ports and port-counties can be divided into two phases: one was oriented by land ports, and the other by portcounties. The land port development has moderated as the number of cargoes imported and exported has decreased. (2) The coupling coordination development of Xinjiang land ports and port-counties has improved and can be divided into three levels: sound coordinated development represented by the Alashankou port; primary coordinated development by the Baketu port; barely coordinated development by the Taykexkin port. (3) The Xinjiang land port development pattern is evolving into a new pattern with the Alashankou and Khorgas ports as its core and other land ports as its wings. However, some port-counties are antiquated, which restricts the further improvement of coordinated development
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Because ecological protection and high-quality development in the Yellow River Basin in China have been elevated as national strategies, it is critical to fully explore factor performance, the microeconomic foundation of high-quality economic development, despite the constraints of the environment. According to Marxist political economics, factor performance consists of factor quality and efficiency. The former one, which stands for the production capacity of factors, is the indispensable premise to fully effect factor performance, whereas the latter one is an inherent requirement to fulfill it. Factor quality and efficiency are integrated into a unified analytical framework to construct an indicator, factor performance. Based on the interactive mechanism between the influences of environmental regulation on upgrading factor quality and on improving factor efficiency, this research empirically analyzed the impact of environmental regulation on factor performance in the Yellow River Basin from 2008 to 2019 using the fixed effect model and mediation model. The results are as follows: (1) Environmental regulation upgrades factor quality through population agglomeration, improves factor efficiency through industrial structure optimization, and thus, promotes factor performance with the joint efforts of the improved factor quality and efficiency. (2) The graphical relationships between environmental regulation and factor quality, efficiency, and performance are U-shaped. (3) The influence of environmental regulation on factor performance varies significantly because of different city scales and economic development levels. Therefore, in areas with high-level economic development, environmental regulation promotes factor performance significantly; in areas with low-level economic development or small urban scale, environmental regulation first inhibits and then boosts factor performance, presenting a U-shaped relationship; notably, in large-scale cities, the relationship between environmental regulation and factor performance is not distinctive. Reasonable standards and intensity of environmental regulation should be determined, and differentiated environmental regulation policies should be formulated according to local conditions so that ecological protection and high-quality economic development in the Yellow River Basin can be achieved.
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Rural territorial space security is not only an important part of the national security system but also the focus of territorial space planning and an important basis for realizing ecological civilization construction and rural revitalization. In addition to regional, comprehensive, and complex characteristics, rural space security has typical dynamic characteristics. Rural spaces in different periods have faced security challenges with different development goals. It is a novel exploration of the microgeographic scale to study territorial space security based on rural space. Therefore, this study takes the loess hilly region as the research area. Based on remote sensing data and statistical data, the rural territorial space security of 323 administrative villages in 18 townships in Lintao County of Dingxi City, Gansu Province, China, was quantitatively evaluated using the entropy method and spatial autocorrelation analysis method, and with the help of geographic detectors, factors affecting rural territorial space security were identified. In addition, due to the geographical particularity of the selected study area, this study fully considers the regionality and localization of the indicators in constructing the relevant evaluation index system, which makes the evaluation results more scientific. The results are as follows: (1) The overall rural territorial space security is at a moderate level in Lintao, with the level of living space security> production space security>ecological space security. Villages with a high safety level (69.73% ) are primarily distributed in the irrigated agricultural areas of the Tao River Valley, whereas villages with a low safety level (30.27% ) are primarily distributed in the dry farming areas in the northern and eastern hilly and mountainous areas of the county. (2) The rural territorial space security in Lintao County has obvious spatial autocorrelation. The local spatial distribution is dominated by three types: high-high (18.52% ), low-high (0.62% ), and low-low (9.26% ). The spatial correlation between villages in the county is mainly positive correlation type and exhibits obvious agglomeration and distribution characteristics. The negative correlation types of village and town units are less distributed and more scattered, indicating their weaker spatial heterogeneity. (3) Topography, population size, government investment, and locational connections have a significant impact on the level of rural territorial space security, and the degree of impact on different townships varies. Based on these findings, subsequent research can focus on the long-term evolution process of rural territorial space security and its driving mechanism and pay attention to the understanding and change of rural territorial space security by different subjects (countries and villagers) in different periods. In the next step, attention should also be paid to the implementation and assessment system of rural territorial space security construction, and explore the establishment of a more rational and fair territorial space security evaluation system to more effectively promote the management practice of territorial space and provide services for the sustainable development of territorial space.
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： As an essential hub of the Silk Road Economic Belt, the coordinated development of landscapedemographic urbanization in Central Asia not only affects the sustainable socio-economic development of Central Asia but also promotes the implementation of the Belt and Road Initiative. We explored the spatiotemporal coupling characteristics of five Central Asian capitals from 2000 to 2019 using the urban expansion mode index, population concentration index, equal fan analysis method, and spatial coupling coordination model. The results are as follows: (1) From the spatial evolutionary characteristics, the expansion type of urban land in five Central Asian capitals is mainly sprawl type, and overall, the expansion mode index tends to increase and then decrease. Regarding population concentration characteristics, the population concentration index in Ashkhabad exhibits an upward trend, whereas that in Dushanbe and Nur Sultan exhibit a downward trend, and those of Tashkent and Bishkek fluctuate between 0.6 and 0.7. (2) In terms of spatial growth trends, the expansion directions of landscape urbanization and demographic urbanization are identical in Bishkek, Ashkhabad, and Nur Sultan, with a slight deviation in Tashkent and a significant difference in Dushanbe. (3) From the coupling coordination characteristics, the landscape-demographic urbanization coupling situation is poorly coordinated in Tashkent, and the coordinated urbanization development is at the initial stage. The coupling coordination situations are better in Dushanbe and Bishkek, but their coordination levels vary widely and are at the fluctuating stage. Ashkhabad and Nur Sultan exhibit high coordination levels and are at the stable stage
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： The landscape diversity index (LDI) is not only an important indicator in landscape ecology research but also an important component in biodiversity conservation. Based on the land use/cover raster data (30-m resolution), the spatiotemporal variation and scale- dependence characteristics of the LDI of an oasis along the Yellow River in Ningxia, China, have been studied using Neighborhood and Focal tools in ArcMap from 1975 to 2000. The results are as follows: (1) The LDI, which is measured by a square with a side length from 90 m to 6000 m, had obvious spatial scale-dependent characteristics based on five times repeat, and its turning point was 3000 m. (2) The change trend of the LDI had been cyclical in the past decades, with a turning point of 2000. During the study period, the LDI exhibited a decreasing trend from 1975 to 2000, and the analysis of LDI zoning indicated that the main characteristics were as follows: the class area (CA) of the degraded area was the largest, and the CA of the improved area was the smallest, which were 6840 km2 and 1332 km2 , respectively. In contrast, there was an increasing trend for the LDI from 2000 to 2020, mainly characterized by the maximum CA in the impervious area and the minimum CA in the degraded area, which were 7848 km2 and 792 km2 , respectively. Because the initial LDI in 2000 was the lowest in the entire period, its improvement status in the later period did not reach that of the early period. (3) The conversions of the LDI-grading area were mainly characterized by the transfer from the early improved area to the late impervious area (796 km2 , 60.5% of the improved area) and the transfer from the degraded area to the impervious area (3519 km2 , 51.5% of the degraded area) and the improved area (3036 km2 , 44.4% of the degraded area), respectively. (4) The change in the landscape diversity pattern was characterized by a negative correlation between CA and relative splitting index, and this relationship mechanism was universal in different periods and change types. Thus, it is to best understand the landscape diversity change with credible spatiotemporal scales in a regional landscape study. It is necessary to ensure that the research results are not only used for reference and sharing but also used to visualize and analyze regional landscape diversity
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Research on the evolution characteristics of loess erosion and the development of watershed geomorphic systems in the Loess Plateau of China is a hotspot in the study of loess landforms, and many related scientific issues still need to be studied. Most previous studies have focused on the erosion and development characteristics of watershed geomorphology, but there is a lack of research on indepth analysis of the geomorphic evolution characteristics of loess small watersheds with multiple rock and soil layers in the field from the perspective of watershed geomorphology system and its potential energy information entropy (PEIE). Therefore, based on the viewpoint and method of system theory, mathematical models of the geomorphic system and its PEIE of a small loess watershed with multiple rock and soil layers were built. Taking the Xindiangou small watershed at Suide County, Shaanxi Province, China as the research sample area, the digital elevation model data of 5 periods from 2000 to 2019 were used to investigate the entropy change law of the PEIE and the characteristics of landform evolution in the watershed. The results show that from 2000 to 2019, the geomorphic evolution process dominated by loess erosion in the Xindiangou small watershed is the process of entropy reduction of its PEIE and continuous erosion of the loess landform. Combined with the entropy change of PEIE in the Xindiangou small watershed and the indoor small watershed, it is speculated that the watershed geomorphic system will form a W-shaped PEIE change curve in its complete geomorphic evolution process, and its PEIE can better indicate the watershed geomorphic development demarcation points in its infancy, maturity, and old age. The research results also confirm the effectiveness of the conceptual model of the loess watershed geomorphic system and its mathematical model of PEIE in the numerical simulation of the Xindiangou small watershed. This model is an extension of the existing mathematical model of PEIE of watershed geomorphic systems with homogeneous single loess layers, which can be used in heterogeneous multiple rock and soil layer loess watershed geomorphic systems and has wider applicability. The research results provide ideas for further research on the geomorphic formation mechanism and evolution law of the Xindiangou small watershed in the future and guide soil and water conservation, ecological restoration, and regional sustainable development of the Xindiangou small watershed, which has important theoretical significance and good application prospects
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Although large-scale ripples (LSRs) are widely distributed in various desert regions of the globe, there are few studies on LSR in China. Through field investigations and observation, remote sensing imagery analysis by Google Earth, and a laser particle size analyzer, spatial distribution patterns and fundamental morphometric and grain size features of both individual and collective forms of LSRs in the Korqin Sandy Land of China are explored. Furthermore, coarse grain sources, differences in granulometric distribution, morphometric features, interior sedimentary structures between LSRs and common ripples, and differences between sands from LSR and common wind ripple are discussed in this study. The results are as follows: (1) LSRs are primarily concentrated on the central and northern parts of Ongniud Bannar, the western extreme of Korqin Sandy Land, and close to or surrounding nearby rocky mountains; they are also primarily distributed in the southern zone of the middle Xilamulun River, on the eastern banks of the Xiangshui River, in the area of the Songshu Mountain, and on the fluvial plain of the lower Chaganmulun River. (2) In line with the dimension, shape, and location of LSRs, plot-, patch-, and stripe-shaped LSR spatial units can be recognized, which are mainly generated on such geomorphic positions as broad interdune, central and upper stoss of a dune, and trough-like lowland, respectively. (3) The average length of LSR is 6.32 m, with an obvious spatial difference; the average strike is NE-SW, significantly perpendicular to the local predominant wind direction and with an insignificant spatial difference; the average spacing is 1.68 m, with a spatial difference; individual LSR has a dissymmetric cross-section. (4) The grains of LSR are comparatively coarser, belonging to the class of middle-coarse sand, which are, however, thinner than those in northwestern China, West Asia, and North Africa; coarse grains are mainly derived from fluvial sediments on ancient river channels, underlying fluvial-lacustrine sediments of late Quaternary, and weathering crusts and alluvial deposits on foothills of nearby denuded mountains. (5) There are considerable differences in appearance, grain composition, geometric morphology, and internal sedimentary structure between LSRs and common sand ripples, which are the smallscale perpendicular bedforms among aeolian depositional landforms and can superimpose on the surfaces of various dunes. The research will, to some extent, advance the principle theories of aeolian geomorphology and effective sand-control practice.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Improving the forecasting accuracy of solar irradiance, as an important safeguard ensuring the stability of grid operations, remains one of the challenging technical bottlenecks. This study constructs a short-time solar irradiance forecasting model (R model) based on the cloud relative radiative forcing ratio R derived by the ground-based solar irradiances from the relationship between clouds and radiation and then evaluates the forecasting accuracy of the R model using 16- year solar irradiance measurements at the Southern Great Plains Central Facility site in the United States. The results show that (1) the R model significantly outperforms the simple persistence model and exhibits a 2%-25% improvement relative to the advanced smart persistence model (also called cloud relative radiative forcing (RCRF) model herein) in the cloudy case. (2) For the overall validation with 2.9×105 individual cloudy casesin 8 categories over 16 years,the forecast accuracy ofthe R model is significantly better than that of the simple model and the RCRF model at lead times longer than 1 h. Compared with the RCRF model, the forecast performance of the R model is improved by 25% and 19% in global horizontal irradiance and direct normal irradiance, respectively, and the lead time is extended by 1.5 and 1 h. (3) The R model with higher forecast performance sets a higher standard for the benchmark model of short-term solar irradiance forecasting. Meanwhile, the R model only requires short-term ground-based radiation observations for forecasting, facilitating and providing new possibilities for photovoltaic power plants without concurrent meteorological measurements in short-term solar irradiance forecasting.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Solar radiation is the primary energy source of the earth’s system and is closely related to human life. By selecting the monthly sunshine hour data of 50 meteorological observation stations in the Qinghai Plateau of China from 1961 to 2020, the spatiotemporal variation characteristics of sunshine hours in the Qinghai Plateau as a whole, different latitudes, and different altitudes were analyzed. The results are as follows: (1) The annual sunshine hours in the Qinghai Plateau exhibit a significant downward trend from 1961 to 2020, and a sudden decrease occurred in 2004. From the perspective of spatial distribution, the annual sunshine hours in other regions showed a significant decreasing trend except that the sunshine hours in some southern stations is flat or slightly increased. And the decreasing trend is most significant in Qaidam area and eastern agricultural area. (2) The decreasing trend of sunshine hours in high-latitude areas is significantly greater than that in low-latitude areas of the Qinghai Plateau. The variation trend of sunshine hours at different latitudes in spring is small. In summer and winter, the decreasing trend of sunshine hours at relatively high latitudes is significantly greater than that at low latitudes, and in autumn, the decreasing trend of sunshine hours at low and high latitudes is significantly greater than that at middle latitudes. (3) The decreasing trend of annual sunshine hours in relatively low-altitude areas of the Qinghai Plateau is significantly greater than that in relatively high-altitude areas. The change trend of sunshine hours at different altitudes in spring is small, flat, or slightly reduced. The decreasing trend of sunshine hours at relatively low altitudes is significantly greater than that at higher altitudes in summer and winter. The sunshine hours at different altitudes in autumn exhibit a decreasing trend, but there is a significant difference in the decreasing trend.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Previous studies have shown that the Emanuel scheme performs relatively well in simulating temperature and precipitation in East Asia. However, the user’s guide of RegCM4.6 points out that the Emanuel scheme tends to produce excessive precipitation over lands, especially in some intense individual precipitation events. In contrast, the Grell scheme tends to produce weak precipitation over tropical oceans. Therefore, the new version of the regional climate model RegCM4.6 has incorporated the Mix cumulus convective parameterization scheme, which means that the Emanuel scheme can be used over oceans and the Grell scheme over land, to compensate for the deficiencies of a single scheme. Previous validation studies have mainly focused on temperature and precipitation, and few studies have been conducted on the Mix scheme. The MODIS product from January 1st , 2016, to December 31st , 2016, was used as a reference to evaluate the simulation results of cloud fraction (CF), ice water path (IWP), and liquid water path (LWP) in East Asia from the Emanuel and Mix schemes in RegCM4.6 at various time scales. Some statistical parameters were calculated, such as the correlation coefficient (r), mean absolute error (MAE), mean bias error (MBE), and root mean square error (RMSE). The results were as follows. (1) The simulated CF were slightly overestimated in the northwest and mainly underestimated in the southeast roughly bounded by the Hu Huanyong line. The performance of the two schemes in simulating CF was the best in summer and the worst in winter. In the four seasons, the absolute values of MAE, MBE, and RMSE of the Mix scheme were generally lower than those of the Emanuel scheme. (2) The systematic deviations of IWP were negative in the whole of East Asia. Except in summer, the IWP from the two simulations and MODIS was significantly negatively correlated in the other three seasons, indicating that it was a challenge to accurately simulate physical processes related to ice particles in the cloud. (3) The LWP was underestimated by the two schemes in the Qinghai Tibet Plateau and Eastern Ocean and was overestimated in southern, central, and northern China, but the annual MBE of the Mix scheme were closer to 0. The performances of the two schemes were similar in winter. In the other three seasons, the absolute values of MAE, MBE, and RMSE of the Mix scheme were less than those of the Emanuel scheme, and the differences in MAE for the two schemes were 21-39 g·m-2 . In conclusion, the Mix scheme is more suitable to simulate cloud water resources in East Asia. This study will contribute to the exploitation of cloud water resources in East Asia and provide a reference for the selection and improvement of the cumulus convection parameterization scheme in a regional climate model.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Drought is the main environmental stressor to crop growth and development and a pivotal natural constraint to high agricultural yield and harvest. Agricultural drought monitoring is typically based on meteorological observations, which, to some extent, cannot reflect the agricultural drought conditions on a regional scale. Taking the Gansu Province of China as the study area, the compositive meteorological drought index (CMDI) was constructed using a random forest regression model and the spatiotemporal pattern and change rule of drought during the crop-growing season (April to September) from 2011 to 2019 in the Gansu Province were analyzed based on MODIS, TRMM, ESA CCI, and other remote sensing data products as well as meteorological station data. The results are as follows: (1) the coefficient of determination (R2 ) of the CMDI and the measured value were all greater than 0.634 in each month; the CMDI has a high spatial correlation with the standardized precipitation evapotranspiration index, showing that the CMDI can reflect the occurrence and development of agricultural drought. (2) The agricultural drought in the Gansu Province exhibited an obvious pattern of regional differentiation, with the drought degree gradually increasing from southeast to northwest. Most parts of the Hexi region were in special and severe drought, the Longzhong region was in severe (medium) drought, and the Longdong, Longnan, and Gannan regions were in fluctuating drought. (3) From 2011 to 2019, the agricultural drought in the Gansu Province exhibited a significant fluctuating trend on both annual and monthly scales, and the drought degree was most moderate in 2012 and most severe in 2017. Agricultural drought has been reduced in the Gannan region in April-September, most areas in April and June, the Longdong region in May, and the Longnan region in September. However, the remaining regions experienced an increasing trend of drought during the crop-growing season from 2011 to 2019
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Research has confirmed that the global terrestrial vapor pressure deficit (VPD) has already increased and will continue to increase. In this context, it is worth exploring whether the atmospheric environment in Xinjiang of China tends to be drier. The VPD series of Xinjiang from 1961 to 2020 was calculated based on meteorological observation data. Then, the distribution and spatio-temporal evolution characteristics of VPD were studied by linear trend analysis, Mann-Kendall test, etc. The results are as follows: (1) From 1982 to 2015, the average annual VPD in Xinjiang exhibited an obvious upward trend with an increased rate of 0.015 kPa·(10a)−1 . As shown in the Mann- Kendall test, an abrupt change in VPD occurred around 2005, and a weakly fluctuating change was observed before the mutation, followed by an increasing trend. (2) There were significant differences in the intensity of VPD in different seasons, but increasing trend changes, even though the rates of increase differed, which appeared in the series of mean VPD values for each season. In comparison, the magnitude of increase in VPD sequences was greater in spring and summer and the smallest in winter. The characteristics of abrupt changes in VPD sequences in spring and autumn were relatively consistent with the changes in the annual VPD value series, whereas summer was slightly later, with the abrupt change that occurred in 2006. (3) Spatially, VPD exhibited a distinct difference of“low in the mountains and high in the basins”, and there was spatial heterogeneity in its long-term evolution trend. A large area of the entire territory (approximately 83.65% of the meteorological stations) exhibited an increasing trend in VPD, whereas the stations with decreasing trends were mostly distributed in the northern foothills of the eastern part of the Tianshan Mountains and the northern/ northwestern edge of the south Xinjiang Basin. On the seasonal scale, the number of meteorological stations with increasing trend changes in VPD in spring accounted for the highest proportion of the total number of stations (96.15% ), indicating that this season is the most extensive period of VPD in Xinjiang. Comparatively, the relatively small variation of the VPD time series showed that the atmospheric dryness during winter in Xinjiang was relatively stable in the long term. This study reveals the evolution of VPD in Xinjiang under a significant shift from warm-wet to warm-dry and serves as a reference for reducing uncertainties in the prediction of changes in ecosystem structure and function
Hits
Hits
Downloads
Comment