Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The Hexi Region holds a dual significance in China, being both a pivotal area for ecological security and the core of the Silk Road Economic Belt. The assessment of the net primary productivity (NPP) of the region and a quantitative analysis of the driving forces behind these dynamics bears immense theoretical importance and practical implications. Based on MOD17A3 product, land use cover, and meteorological information, this study scrutinized the evolving characteristics of the vegetation- related NPP, the influence of land use cover changes, and climate fluctuations on the NPP of the Hexi Region from 2000 to 2020. This study employed R-contribution rate and biased correlation analysis methods. The results show that: (1) There was an overall increase in the area of arable land, waters, and residential land in the Hexi Region, while the grassland and unused land area was reduced. The overall dynamics of land use cover change (LUCC) after 2010 was significantly higher, with grassland, cropland, built- up land, and unused land dominating the inter- conversion of land use types. (2) The overall NPP in the Hexi Region increased, with rates of change of 0.86 and 1.29 in the periods 2000-2010 and 2010-2020, respectively. There was a significant regional variation in NPP, which decreased from southeast to northwest. (3) The influence of LUCC on NPP gradually increased from 2000 to 2020. While climate change contributed more to NPP than LUCC, their respective roles varied among land use cover types. Specifically, climate change dominated the influence factor of NPP on cropland, forested land, and grassland, whereas for unutilized land and residential construction areas, LUCC played a more significant role.
Subjects: Geosciences >> Geography submitted time 2023-03-15 Cooperative journals: 《干旱区地理》
Abstract： Improving the green development efficiency (GDE) is crucial for constructing ecological civilization and high-quality development in Gansu Province, China. Based on the Super-SBM model, hotspot analysis and the geographic detector model, Gansu Province from 2005 to 2019 was analyzed for the spatiotemporal evolution characteristics and driving factors of the GDE in 14 cities and prefectures. The following results are obtained: (1) Temporally, the GDE shows a pattern of“M”- shaped fluctuated growth, and the regional relative difference demonstrates a corresponding trend of fluctuation. (2) Spatially, the spatial heterogeneity of the GDE is significant, and the gradient difference in the north- south direction is significantly greater than that in the eastwest direction. However, the degree of spatial agglomeration of the GDE is weak, dominated by low hot-spots, middle hot-spots, and low cold-spots. Additionally, the GDE displays a characteristic of spatial club convergence. (3) Marketization level, innovation ability, government regulation, and urbanization level are the driving factors of GDE. The GDE in Gansu Province is the result of the multifactor interaction. The results not only enrich the index system and case study of GDE but also can provide references for the green transformation development of Gansu Province and other less developed areas.
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 城市绿化是城市建设的重要内容，是实现城市生态文明、生态宜居的重要途径。选取中国292个地级及以上城市，基于变异系数、泰尔指数、空间自相关和地理探测器等方法，刻画了2000-2017年中国城市绿化水平的时空演变和影响因素。结果表明:(1) 2000-2017年中国城市绿化水平呈阶段性波动增长态势，全国城市绿化水平增幅为6. 73 %，其中西部地区绿化水平增加最为显著，改变了2000-2014年保持的“东一中一西”逐渐递减的绿化格局，形成了由沿海向内陆跃升的绿化格局。( 2 ) 2000-2017年中国城市绿化水平的总体差异与东、中、西三大区域的差异均呈降低趋势。从泰尔指数变化趋势来看，总体差异主要由区域内差异引起，且区域内差异与区域间差异在逐渐缩小。(3)东部形成一定规模的稳定性热点区，西部形成局部性热点区与一定规模的稳定性冷点，从而使得我国由“东一中一西”逐渐递减的绿化格局转变为由沿海向内陆跃升的绿化格局更为显著。(4)自然因素是城市绿化水平的基础性影响因素，经济发展水平和政府管理为阶段性关键因子，是促使各时段城市绿化格局演变的动力因子。
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 基于2012年6-8月的实测水汽同位素数据及相关气象数据，对黑河中游夏季昼夜的同位素基本特征、水汽来源方向及潜在蒸发源地进行了研究。结果表明:空气水汽线斜率白天大于夜晚和水汽过量氖值白天大于夜晚，综合说明白天局地蒸发较夜晚强烈;夏季受西风水汽影响显著。其中，6月主要受西风水汽和北冰洋水汽影响，大8月主要受西风水汽和东南方向水汽影响，且8月受东南方向水汽影响最为明显;水汽运移路径上下垫面地形和气压带移动会影响水汽后向轨迹高度，西北方向上水汽输送通道较顺畅，风速较大，有利于水汽的输送;水汽蒸发源地主要集中在研究区周围及以东、以北部，其次是西北部。绿洲是主要的水汽蒸发源地，其次是城市和河流，白天较夜晚局地蒸发强烈且面积大。
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 基于甘肃省河东地区61个气象站点1988-2017年逐日气温数据，利用Mann-Kendall检验，Sen's斜率估计方法分析甘肃省河东地区极端气温指数的时空变化趋势，并探讨极端气温指数与其影响因素之间的关系，最后利用NAR神经网络结合Hurst指数对甘肃省河东地区极端气温指数变化进行预测分析。数变化有密切关系，而太阳黑子等只与个别指数之间存在显著的相关性。(5)预测出的极端气温指数冷极值相对指数仍呈现下降趋势，冷极值的绝对指数、暖极值以及气温日较差、作物生长期仍然呈现增加趋势，但大多数指数与1988-2017年相比变化幅度有所降低。(6)与其他区域相比甘肃省河东地区大多数气温指数变化幅度处于中间水平，表现出其为多种不同气候区、自然区交界地带的特色。结果表明:(1)从时间上看，冷极值相对指数呈下降趋势，冷极值绝对指数、暖极值以及气温日较差、作物生长期呈上升趋势。(2)从空间上看，对冷极值变化反应最为敏感的是高寒湿润区，对暖极值变化反应最为敏感的是温带半湿润区和北亚热带湿润区，除北亚热带湿润区外各区域作物生长期的变化都达到了显著水平，而气温日较差仅在温带半湿润区达到了显著水平。(3)多数极端气温指数与经纬度、海拔之间有显著相关性，但受区域自然特点影响，经度与海拔对其影响实为一类。(4)亚洲区极涡强度、北半球极涡强度以及青藏高原指数B与极端气温指
Subjects: Geosciences >> Hydrology submitted time 2020-01-02 Cooperative journals: 《干旱区研究》
Abstract： 植物功能性状是连接植物与外界环境的重要桥梁，其在不同环境梯度下的变化表现出了对异质环境的适应机制。本文以敦煌西湖国家级自然保护区克隆植物芦苇（Phragmites australis）为研究对象，设置了未退化、轻度退化、中度退化和重度退化4个梯度样地，研究环境异质条件下芦苇叶功能性状特征及其对土壤环境因子的响应。结果表明：① 各环境梯度下，芦苇叶功能性状特征变化显著（P<0.05），叶长、叶宽、叶面积、叶干重随环境梯度退化呈下降趋势，比叶面积随梯度退化呈上升趋势；② 芦苇各叶功能性状间呈协同变化的特征，叶长、叶宽、叶面积、叶干重之间呈极显著正相关（P<0.01），比叶面积与叶长、叶干重呈显著负相关（P<0.05）；③ 叶长、叶宽、叶面积、叶干重与土壤表层（0~30 cm）、中层（30~60 cm）水分呈显著正相关（P<0.05），而与土壤表层、中层含盐量呈显著负相关（P<0.05），说明土壤表层与中层的水分与盐分是芦苇叶功能性状最主要的驱动力。研究结果对干旱区内陆河湿地的保护、生态恢复及管理具有重要的指导意义。
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