Subjects: Geosciences >> Geography submitted time 2024-04-01 Cooperative journals: 《干旱区地理》
Abstract：近几十年来新疆气候变化显著，“暖湿化”转型与“湿干转折”先后出现，势必对地区植被生产力、大气干旱状况以及二者间的响应关系产生影响。以植被总初级生产力（GPP）和大气水分亏缺（VPD）作为评价指标，分析了1982—2018年新疆地区植被GPP、VPD的时空分布与演变规律，并揭示了大气水分胁迫对植被GPP的影响。结果表明：（1）新疆植被GPP整体具有北高南低的分布特征，年均值为256.6 g C·m-2·a-1，呈显著上升趋势。GPP增加趋势占植被总面积的82.00%，其中增加显著区约占42.81%，多分布于南疆绿洲和北疆山前农业区；GPP下降趋势占比较小且分布零散。（2）新疆地区VPD具有“山区低、平原/盆地高”的鲜明格局，年均值为0.66 kPa，呈不显著波动上升趋势。全疆大部地区表现出VPD显著性上升，下降趋势零星出现在昆仑山脉高海拔山区。（3）新疆植被GPP对VPD的响应“正负共存”，并具有明显空间异质性。GPP与VPD的负相关占植被区总面积的54.52%，主要出现在山前草地地带；正相关则主要分布在塔里木盆地边缘和天山北坡及其东段，以栽培作物和灌木类型为主。VPD对GPP的影响在不同植被类型间差异鲜明，而在同一植被类型内正、负响应共存。分析认为，虽然大气水分胁迫尚未成为地区植被生产力变化的主导驱动力，但在新疆干旱化急剧增加背景下，仍需加强对GPP与VPD响应关系的跟踪。
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
Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-06-17 Cooperative journals: 《干旱区地理》
Abstract： 利用2000—2017年MODIS NPP数据与气象观测数据，采用趋势分析及相关分析法，揭示 了新疆地区植被净初级生产力（NPP）时空演变格局及其对气候变化响应的海拔分异性。结果表明：（1）18 a间，新疆植被NPP年均值为145.96 g C·m-2，以4.422 g C·m-2·(10a)-1速率呈不显著增长；受地形及区域水热条件的制约，植被NPP表现出北疆优于南疆、山区优于平原的分布规律。（2）NPP均值大体上随海拔的增加先增后减。在海拔3900 m）地区取代降水成为限制植被活动的主导因子。在不同海拔梯度下，植被NPP与气温主要呈负相关性，与降水量呈正相关性，且相关性在海拔<1400 m时有更突出的梯度差异。
Hits
Hits
Downloads
Comment