新疆自然植被对非对称性昼夜增温的时滞响应

为探究新疆地区植被活动与昼夜增温之间的复杂关系，本文利用2000~2015年归一化植被指数（NDVI）及气象数据，定量研究了新疆北疆、南疆及伊犁地区生长季日间最高气温（T_max）、夜间最低气温（T_min）变化趋势及植被对非对称性累积昼夜增温的时滞响应，通过二阶偏相关分析了T_max、T_min对新疆地区植被的影响.结果表明：北疆、南疆及伊犁地区昼夜增温均呈非对称性，昼夜增温空间异质性显著，北疆地区T_min增温速率为T_max增温速率的1.67倍，南疆地区T_min增温速率为T_max增温速率的1.59倍，伊犁地区T_min增温速率为T_max增温速率的2.67倍，伊犁地区昼夜温差缩小趋势显著.植被对非对称性昼夜累积增温时滞性呈现明显的空间差异，T_max、T_min对新疆地区植被平均滞后时间为（0.97±0.93）个月和（0.91±0.95）个月.南疆、北疆及伊犁地区针叶林、阔叶林及草甸草原植被受日间增温的影响，荒漠草原、典型草原受夜间增温影响显著，夜间增温影响范围更广.

Time lags responses of terrestrial natural vegetation to asymmetric diurnal warming in Xinjiang

In order to explore the complex relationship between vegetation productivity and diurnal warming in Xinjiang, this study quantitatively analyzed the variation trend of diurnal warming and the temporal lagging in responses of vegetation, via Normalized Difference Vegetation Index, to asymmetric diurnal warming in the northern of Xinjiang, southern of Xinjiang and Yili valley. The results indicated that:The trend of the diurnal warming in all the three regions were asymmetric with a significant spatial heterogeneity. The nighttime warming was approximately 1.67 times that of daytime in northern Xinjiang during growing seasons, 1.59 times in southern Xinjiang, and 2.67 times in Yili valley. The diurnal temperature difference reduced significantly in Yili region. There was a significant difference in the response of vegetation to the asymmetric diurnal accumulated temperature. The average temporal lags of vegetation response to cumulative T_max and T_min in Xinjiang were approximately (0.97±0.93) months and (0.91±0.95) months. Overall, the daytime warming had significantly positive effects on the coniferous forests, broad-leaved forests and meadow grassland vegetation in all three regions; and the nighttime warming had significantly positive effects on the desert grassland and typical grassland.