新疆植被总初级生产力对大气水分亏缺的响应OA北大核心CSTPCD

Climate change in Xinjiang,China,has been remarkable in recent decades.With a significant shift from warm-wet to warm-dry,regional vegetation productivity,atmospheric drought conditions,and the response relationship between them will inevitably be affected.Based on multisource data such as ground meteorological observations and reanalysis data,considering remote sensing products,vegetation gross primary productivity(GPP),and vapor pressure deficit(VPD)as indicators,this study analyzed the spatial-temporal distribution and evo-lution patterns of vegetation GPP and VPD in Xinjiang from 1982 to 2018,as well as the influence of VPD changes on GPP.The results are as follows:(1)The annual mean GPP in Xinjiang was higher in the northern region,espe-cially the mountains,than in the southern region.The annual mean GPP in Xinjiang was 256.6 g C·m-2·a-1 with a significant upward trend in interannual variability(R2=0.72,P<0.01).Approximately 82.00%of the total vegeta-tion area showed an increasing trend,of which the area with significant increase accounted for 42.81%,mostly distributed in the oasis at the edge of the Tarim Basin in southern Xinjiang and agricultural areas on the north slope of Tianshan Mountains.The area with a decreasing GPP trend accounted for a small percentage,and its dis-tribution was scattered.(2)VPD showed a distinct difference of"low in the mountains and high in the basins".A nonsignificant fluctuating upward trend was observed in the VPD,with an annual mean value of 0.66 kPa.Signifi-cant increases in VPD occurred in approximately 82.02%of the whole territory,predominantly in the Tarim and Junggar Basins.In contrast,decreasing trends occurred sporadically in the high-altitude mountainous areas of the Kunlun Mountains.(3)Overall,the response of GPP to VPD was characterized by a distinct spatial heterogeneity with positive and negative correlations.The negative correlation between GPP and VPD accounted for 54.52%of the total vegetation area,mainly in the grassland at the front edge of the mountain.While the positive correlation was mainly distributed at the edge of the Tarim Basin,the northern slope of the Tianshan Mountains and its east-ern section were dominated by cultivated crops and shrubs.Comparative analyses showed that GPP-VPD correla-tions differed significantly across vegetation types.The study proved that the change in VPD has already affected the vegetation productivity in Xinjiang.Although it has not yet become a major limiting factor,there is still a need to strengthen the tracking of the GPP and VPD response relationship to provide a scientific reference for op-timizing ecological restoration and governance.