天山北坡植被NPP时空格局及气候因子驱动分析

Spatial-temporal Distribution of NPP and Its Climatic Driving Factors in the Northern Slope of Tianshan Mountain

【目的】研究天山北坡植被净初级生产力(NPP)的时空格局,分析NPP与气候因子的关系,为天山北坡自然资源的合理开发利用与管理提供科学依据。【方法】利用CASA模型估算天山北坡植被的NPP,分析其年内时空变化特征,采用相关性分析法研究天山北坡NPP与气候因子的关系。【结果】(1)2015年天山北坡NPP总量为34.57 Tg C,平均值为173.34 g C/(m2·a),中西部区域NPP占天山北坡总量的82.25%,是天山北坡NPP的主要供给区,山地区域的NPP平均值最高。(2)不同植被类型的NPP差异较大,林地、耕地、草地、未利用地分别为534.47、333.47、174.20和124.18 g C/(m2·a)。(3)天山北坡NPP月总量波动在0.29~3.00 Tg C/mon,6月NPP达到一年中最大值,为7.39 Tg C/mon。草地NPP随季节的波动幅度最大,林地随季节波动幅度最小。NPP季节变化表现为夏季>春季>秋季>冬季。(4)温度对天山北坡不同植被类型的影响大于降水。NPP的变化受气候因子驱动影响的区域占66.06%,主要集中在天山北坡中西部区域;非气候因子的影响占33.94%,主要集中在天山北坡中东部以北地区。【结论】天山北坡NPP总体上呈现西高东低的趋势,不同植被类型随季节的变化趋势不同,温度是天山北坡NPP年内变化的主要影响因素。

【Objective】This project aims to study the spatial and temporal pattern of the net primary productivity(NPP)in the northern slope of Tianshan Mountain,analyze the relationship between NPP and climate factors and provide scientific basis for rational exploitation,utilization and management of natural resources there.【Method】The CASA model was used to estimate the NPP of vegetation in the northern slope of Tianshan Mountain in 2015 and its spatial and temporal variation characteristics of the year were analyzed.In addition,the correlation between NPP and climate factors was analyzed by using the correlation analysis method.【Result】(1)In 2015,The total NPP of the northern slope of Tianshan Mountain was 34.57 TgC/a,with an average of 173.34 gC/(m 2·a).The NPP in central and western regions accounted for 82.25%,which was the main supply area,and the average value of NPP in the mountainous region was the highest.(2)The NPP of different vegetation types was different,in the forestland,cultivated land,grassland and unused land,they were 534.47 gC/(m 2·a),333.47 gC/(m 2·a),174.20 gC/(m 2·a)and 124.18 gC/(m 2·a)respectively.(3)The total fluctuation range of vegetation NPP was between 0.29-3.00 TgC/mon in the northern slope of Tianshan Mountain,and in June it reached the maximum of the whole year,which was 7.39 TgC/mon.Grassland NPP had the largest fluctuation amplitude with seasons,while woodland had the smallest one.The seasonal variation of NPP was summer>spring>autumn>winter.(4)The influence of temperature on different vegetation types in northern slope of Tianshan Mountain was greater than that of precipitation.66.06%of NPP changes were driven by climate factors,mainly concentrating in the central and western regions of the northern slope of the Tianshan mountains.The impacts of non climatic factors accounted for 33.94%,mainly concentrating in the east midlands in the northern slope of Tianshan Mountain.【Conclusion】The NPP of the northern slope of the Tianshan Mountain shows a trend of"west high and east low",different vegetation trends vary with the seasons,and the temperature is the main influencing factor of the change of vegetation NPP in the northern slope.