Spring Phenological Sensitivity to Climate Change in the Northern Hemisphere: Comprehensive Evaluation and Driving Force Analysis

Plant phenology depends largely on temperature, but temperature alone cannot explain the Northern Hemisphere shifts in start of growing season (SOS). The spatio–temporal distribution SOS sensitivity to climate variability has also changed recent years. We applied partial least squares regression (PLSR) method construct a standardized evaluation index and analyzed combined effects air (Tem), water balance (Wbi), radiation (Srad), previous year’s SOS. spatial temporal distributions change from 1982 2014 were using time windows 33 15 years; dominant biological environmental drivers assessed. results showed that (SCom) is most influenced by preseason sensitivity. However, because asymmetric response daytime/night (Tmax/Tmin) non-negligible moderating Wbi Srad SOS, SCom was more effective expressing effect than any single climatic factor. Vegetation cover (or type) factor influencing pattern sensitivity, followed spring (Tmin > Tmax), weakest balance. Forests had highest absolute values. A significant decrease some vegetation (22.2%) led decreasing trend Hemisphere. Although remains main driving changes SCom, between winter (Tems/Temw). More moisture might mitigate spring/winter warming. adaptation greater influence relative each (Tems, Temw, Wbi, Srad). This study provides basis for assessment prediction.