2000-2012年青海湖流域NPP时空分布特征

利用青海湖流域及周边地区气象资料和MODIS遥感影像等数据,结合地理信息系统技术和植被净初级生产力(NPP)估算模型(CASA模型),确定了2000-2012年青海湖流域NPP值,并评价了其时空分布特征。结果表明:2000-2012年青海湖流域年均NPP为4.77×10¹² g,空间分布以青海湖为中心,由低到高呈环带状,并呈由东南向西北递减趋势,在青海湖北侧河流中游地区年均NPP达到最高,为374.19 g·m^-2。2000-2012年NPP呈波动中逐渐增长趋势,年均增加4.81×10¹⁰ g;NPP年内变化显著,7月NPP达到全年最高值,占全年的28.77%。13年间流域内大部分地区NPP呈增长趋势,显著增长区主要分布在共和县江西沟乡、石乃亥乡和天峻县周围;青海湖北侧哈尔盖河上游、沙柳河中游地区则是主要减少区。多元回归分析表明归一化植被指数(NDVI)和降水是青海湖流域NPP的主要影响因素。

Spatial-temporal Characteristics of the Vegetation Net Primary Production in the Qinghai Lake Basin from 2000 to 2012

Using the meteorological data and MODIS data, the CASA model and Geographic Information System were applied to analyze the NPP change in the Qinghai Lake Basin during 2000-2012. The results showed that the annual NPP was 4.77×10¹² gC·a^-1, and spatially, NPP distribution from low to high in a ring-shaped around the Qinghai lake, and showed a decrease trend from southeast to northwest, the highest NPP was 374.19 gC·m^-2·a^-1 in the middle region of the Qinghai Lake north river. The inner-annual variation of NPP was obvious and an periodicity increasing tendency with a mean change rate of 4.81×10¹⁰gC·a^-1 could be seen from 2000 to 2012; The NPP changed significantly in a year, July had the highest NPP account 28.77%. Most parts of Qinghai Lake Basin had an increase in total NPP , the significant increase area mainly distributed around the Gong He county in Jiang Xi-gou town, Shi Nai-hai town and Tian Jun county, expect the upstream of the Ha Er-gai river and the midstream of the Sha Liu river were the mainly decrease region. Multiple regression analysis showed that NDVI and precipitation were the main factors influenced the NPP in the Qinghai Lake Basin.