2000-2012年山西省不同植被类型物候变化及其对气候变化的响应

Phenological Variation of Different Vegetation Types and Its Response to Climate Changes in Shanxi Province from 2000 to 2012

利用非对称高斯函数重建山西省2000—2012年MODIS-NDVI时间序列影像,通过动态阈值法提取植被生长季始期(SOG)、生长季末期(EOG)、生长季长度(LOG)信息,研究不同植被类型物候的时空变化及其与气候因子(气温、降水、日照时数)的相关关系。结果表明:(1)13a来,山西省不同植被类型物候的年际变化均表现出SOG提前、EOG推迟、LOG延长的趋势。(2)山西植被物候存在明显的空间差异。植被平均物候由南向北表现为SOG逐渐推迟,EOG逐渐提前,LOG逐渐缩短。从变化趋势看,研究区大部分地区表现出植被SOG提前、EOG推迟、LOG延长的趋势。其中,SOG提前、EOG推迟、LOG延长的地区主要分布在昕水河以北的黄河干流、汾河上游、桑干河、滹沱河等地区;而SOG推迟、EOG提前、LOG缩短的地区主要分布在管涔山、恒山、五台山、吕梁山、太岳山南部等地区。(3)降水和日照时数可能是影响该区植被物候的主要因素,不同植被类型物候对气候变化的响应不同。春季降水增多和3月平均日照时间变短可能是植被(针叶林除外)SOG提前的主要原因,9月降水量增多和平均日照时间变短可能是植被(针叶林和草甸除外)EOG推迟的主要原因。

We reconstructed time-series MODIS-NDVI data of Shanxi Province from 2000 to 2012 by asymmetric C-aussian function and extracted S（）G, EOG and LOG of vegetation by dynamic threshold method. We analyzed spatiotemporal variation of different kinds of vegetation phenology and investigated the correlation between vegetation phenology and climate factors （temperature, precipitation and sunshine duration）. The result showed that： （1） SOG of vegetation presented the advancing trend, EOG of vegetation showed the delady trend, and LOG of vegetation showed the prolonging trend at various degrees during 13 years in Shanxi Province; （2） the spatial variation of vegetation phenology was obviously different, average phenology of vegetation from south to north in Shanxi Province showed that SOG of vegetation was gradually postponed, EOG of vegetation was gradually advanced and LOG of vegetation was gradually shortened, based on the variation trend, SOG of vegetation showed the advancing trend, EOG of vegetation showed the delayed trend, and LOG of vegetation showed the prolonging trend in most research areas; the region in which SOG of vegetation was advancing, EOG of vegetation was postponing and LOG of vegetation was prolonging mainly distributed in mainstream of Yellow River in the north of Xinshui River, upstream of Fenhe River, Sanggan River and Hutuo River; in contrast, the region in which SOG of vegetation was postponing, EOG of vegetation was advancing and LOG of vegetation was shortening mainly distributed in Guancen Mountain, Hengshan Mountain,Wutai Mountain, I.tiliang mountain and the south of Taiyue Mountain; （3） we found that variations of different vegetation phenology events probably were controlled by precipitation and sunshine duration, the response of vegetation phenology to climate change differed among vegetation types; increasing precipitation in spring and shortening sunshine duration in March probably were main reasons for SOG advancing of vegetation besides conifers, and the increasing precipitation and shortening sunshine duration in September probably were main reasons for EOG postponement besides conifers and meadow.