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植物生长季的变化反映了全球气候变化对生态环境的影响。本研究以2000-2006年间MODIS-NDVI影像数据集,使用TIMESAT软件从归一化植被指数(NDVI)时间序列中,分别提取福建省不同森林植被的生长季开始日期(Start of Season,SOS)、生长季结束日期(End of Season,EOS)和生长季长度(Length of season,LOS)等物候参数,并与全省尺度的气温与降水量进行相关分析。结果表明:不同森林类型NDVI与当月月均气温之间具有较显著的相关性(R2为0.72-0.79,p<0.01),同期温度变化对植被生长的影响相对于降水量更重要;而植被生长对降水量的响应存在大约2个月的时滞效应(R2为0.54-0.75,p<0.01),说明前期的降水累积对于后续植被生长有较显著影响。福建省森林植被生长季持续时间约213~223 d,开始于每年4月初到4月中旬(第98~103 d),结束于11月中旬前后(第316~321 d)。其中,南亚热带森林生长季长于中亚热带森林,相同气候条件下的阔叶林生长季时间略长于针叶林。另外,春季(2-4月)气温变化是导致福建省内2个气候带森林生长季开始时间、生长季结束时间及生长季长度变化的关键因素,而伴随春季温度升高,植被生长季开始时间提前(R2为0.83,p<0.01),同时生长季长度延长(R2为0.80,p<0.01)。7 a间,生长季持续时间呈现微弱延长趋势,总体延长幅度为2.4~3.1 d。
Changes in plant growth season reflect the impact of global climate change on the environment. In this study, the MODIS-NDVI image dataset from 2000 to 2006 was used to extract the Start of Season (SOS) of different forest vegetation in Fujian Province from the normalized NDVI time series using TIMESAT software. End of Season (EOS), and Length of season (LOS), were calculated and correlated with the temperature and precipitation over the province scale. The results showed that there was a significant correlation between NDVI of different forest types and the monthly average temperature of the current month (R2 = 0.72-0.79, p <0.01), and the effect of temperature change on vegetation growth was more important than the precipitation during the same period. The response to precipitation has a lag effect of about 2 months (R2 = 0.54-0.75, p <0.01), indicating that precipitation accumulation in the early stage had a significant effect on the subsequent vegetation growth. The growing season of forest vegetation in Fujian Province lasts about 213 ~ 223 d, beginning from April to mid-April (98 ~ 103 d) and ending in mid-November (from 316 to 321 d). Among them, the growing season of South Asia subtropical forest is longer than that of the subtropical forest, and the growth season of broad-leaved forest under the same climatic conditions is slightly longer than that of coniferous forest. In addition, the change of temperature in spring (February-April) was the key factor that led to the start of forest growth season, the end of growing season and the growth of growing season in two climatic zones in Fujian Province. However, with the increase of spring temperature, the vegetation growth season started The time was earlier (R2 was 0.83, p <0.01) and the length of growing season was longer (R2 0.80, p <0.01). During the period of 7 a, the duration of the growing season showed a slight lengthening trend with an overall increase of 2.4-3.1 d.