Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The Tarim River is the largest inland river in China, and had historically nine river systems and one main stream with 144 rivers. At present, only the Aksu River, the Hetian River, the Yarkant River, and the Kaidu-Kongque River have surface hydraulic connections with the main stream of the Tarim River. The connectivity of river systems and ecological protection in the Tarim River Basin are very prominent. In the past 30 years, the downstream of the cut-off river has become the most serious area of ecological degradation in the Tarim River Basin. Based on field investigation and sample pilot survey, this paper systematically analyzes the problems existing in the river system connectivity of the Tarim River Basin, and points out that the connectivity of the river system is poor and the ability to withstand extreme climatic hydrological events is insufficient. The area of cultivated land continues to expand, and the proportion of agricultural water use is too high, which strongly occupies the ecological water use, leading to the cutoff of river channels, dismember of rivers, and damage to the integrity of river basin water system. The groundwater overexploitation causes the groundwater level to drop sharply, the surface ecology process is damaged, and the ecology hidden worry is prominent. In view of this, the following points are put forward: (1) promote and realize scientific management of water resources in Tarim River Basin from mechanism and system. Brought the five source streams that have been cut off into the unified management of the Tarim River
Subjects: Biology >> Botany submitted time 2022-12-01 Cooperative journals: 《广西植物》
Abstract：
To explore the photosynthetic system adaptation mechanism of two dominant ephemeral plants, including Malcolmia scorpioides and Arnebia decumbens, to light and temperature, this study measured the chlorophyll fluorescence parameters and discussed its light damage and the change of photosynthetic activity under different temperatures (25-60 ℃) and constant room temperature and high temperature and different illumination (80-400 μmol·m-2·s-1). The results were as follows: (1) The photosynthetic efficiency and electron transfer rate increased first and then decreased with the increase of temperature, reaching the highest value at 40 ℃, and then rapidly decreased, and the quantum yield of non-regulated energy dissipation in PS Ⅱ [Y(NO)] and PS I receptor side heat dissipation efficiency [Y(NA)] increased, and the photosynthetic system was damaged due to the accumulation of excitation pressure at the receptor terminal. (2) Under the light range of 80-400 μmol·m-2·s-1 and room temperature, the photosynthetic efficiency increased with the enhancement of light intensity; Under high temperature, the combined stress of light and high temperature on plants descended the photosynthetic activity of plants and the quantum yield of regulatory energy dissipation in PS II [Y(NPQ)], and when the light intensity reaches 320 μmol·m-2·s-1, the ring electron transport flow disappeared. In conclusion, light and temperature within a certain range can improve the photosynthetic activity, activate heat dissipation and ring electron transport flow and reduced photoinhibition. However, with the increase of temperature and light intensity at high temperature, the adaptation ability of the two ephemeral plants decrease and the photoprotective mechanism disappeared. The main reason is the failure of regulatory heat dissipation and the accumulation of PS I receptor side excitation pressure.
Subjects: Geosciences >> Geography submitted time 2020-01-06 Cooperative journals: 《干旱区地理》
Abstract：在全球变化的背景下，植被生产力发生了一系列的变化，如何定量的评估中国西北干旱区气候变化和人类活动对植被生产力的影响，对于应对气候变化，促进“一带一路”生态建设以及美丽中国建设具有重要的意义。以新疆为研究区，以植被净第一性生产力（NPP）作为评价指标，分析了2001—2016年气候变化和人类活动对植被恢复和退化的影响。结果表明：（1） 从2001—2016年，植被NPP有明显变化趋势的面积占植被覆盖区总面积的34.02%，其中30.58%的面积呈现恢复趋势，3.44%的面积呈现退化趋势，NPP平均每年增加634 Gg C·a-1(Gg=109 g)。（2） 由人类活动和气候变化引起植被恢复的面积占植被NPP变化总面积的42.03%和30.58%；在上述两个区域，NPP平均每年增加量分别为319 Gg C·a-1和59 Gg C·a-1。由人类活动和气候变化引起植被退化的面积占NPP变化总面积的57.63%和19.45%；其中，在上述两个退化区域，NPP平均每年分别减少68 Gg C·a-1和7 Gg C·a-1。（3） 不同植被类型中，人类活动对农作物、荒漠、草地、高山植被的恢复作用大于退化作用，对森林、灌丛、沼泽的退化作用大于恢复作用；气候变化对沼泽的退化作用大于恢复作用，对其他6种植被类型的恢复作用大于退化作用。总体上，人类活动是影响新疆植被恢复和退化的主要原因。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2019-11-14 Cooperative journals: 《干旱区研究》
Abstract： 潜在蒸散发在区域水量平衡、干旱程度评价、农作物需水量等方面的研究中具有重要的作用。然而，潜在蒸散发的空间化处理一直以来都是相关研究面临的一个挑战。基于新疆地区1960—2017年66个气象站的观测数据，通过一种简单的参数方程，实现了潜在蒸散发（ET0）的空间化处理。研究结果表明：① 简化参数方程中的2个重要参数a，c的空间分布呈现一定的规律，参数a在空间上呈现东南高，西北低的特点；参数c则随海拔的增加而增大。② 简化参数方程与Penman-Monteith方法相比，拟合结果在日、月和季节尺度上的R2值均大于0.90，且R2值随时间尺度的增加而增加。③ 将简化参数方程的拟合结果与CRU数据和MOD16A2数据进行对比发现：简化参数方程与Penman-Monteith方法拟合的R2值较高，拟合效果和偏差指标表现更佳，而CRU、MOD16A2数据拟合的R2值较低。简化参数方程所获得的潜在蒸散发精度高且空间分辨率更高（500 m×500 m），是一种适用于新疆地区潜在蒸散发估算的简便有效的方法。
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