基于Daycent模型的三江源地区草地NPP估算及其对气候变化的响应

Estimation of grassland net primary productivity in Three-River Headwaters region based on Daycent model and its response to climate change

摘要:

【目的】探求 1971-2020 年草地 NPP 的时空变化特征及其与气候因子的关系。【方法】基于 Daycent 模型估算三江源地区草地 NPP，结合同期温度和降水数据，运用多元回归分析法进行分析。 【结果】1)三江源地区草地 NPP 多年的年平均值为 168. 10 gC/m² ，空间上呈现东高西低，南高北低的格局。2)高寒草甸类年均 NPP 为 227. 44 gC/m² ，高寒草原类年均 NPP 为 117. 23 gC/m² 。3)当降水量小于 450 mm 时，温度与草地 NPP 呈正相关；当降水量大于 450 mm 时，温度与草地 NPP 呈负相关。【结论】三江源地区草地 NPP 呈自东南向西北递减的空间格局；不同草地类型中，高寒草甸类年均 NPP 大于高寒草原类年均 NPP，且高寒草原类年均 NPP 有显著的增加趋势；三江源地区的草地 NPP 与降水量呈显著相关关系，温度对该地区的草地 NPP 也有影响。

Abstract:

【Objective】 This research was to explore the spatial‐temporal variation of grassland net primary pro‐ ductivity (NPP) and its relationship with climate factors during 1971~2020.【Method】 Based on the Daycent model， the grassland NPP in the Three ‐River Headwaters region was estimated， and multiple regression analysis was used in conjunction with temperature and precipitation data in the same period of time.【Result】1) The average annual NPP in Three ‐River headwaters region was 168. 10 gC/(m² ·a)， and presented a pattern with higher in the east and south ， but lower in the west and north. 2) The average annual NPP of alpine meadow was 227. 44 gC/(m² · a)， and the average annual NPP of alpine grassland was 117. 23 gC/(m² ·a). 3) When precipitation was less than 450 mm， the grassland NPP was positively correlated with temperature . When precipitation was greater than 450 mm， the NPP of grassland was negatively correlated with temperature.【Conclusion】 The grassland NPP in the Three ‐ river Headwaters region showed a spatial pattern of decreasing from southeast to northwest； Among different grass‐ land types， the average annual NPP of alpine meadow was higher than that of alpine grassland， and the average an‐ nual NPP of alpine grassland had a significant increasing trend；There was a significant correlation between grassland NPP and precipitation in the Three ‐River headwaters region. Temperature also influenced grassland NPP in this re‐ gion.