摘要: 利用CASA 模型（Carnegie-Ames-Stanford Approach）模拟石羊河流域20002020 年植被净初级生产力（NPP），分析流域NPP的时空变化特征、稳定性和未来变化趋势，并从气候因素、地形因素和人类活动因素3个方面探讨对NPP的变化影响。结果表明：（1）20002020年石羊河流域植被NPP多年平均值为291.01 g Cm-2a-1，呈不显著增加趋势，空间分布呈南高北低的分布格局。（2）2000年以来植被NPP呈增加趋势的区域占总面积的86.4%，其中极显著增加和显著增加的区域分别占6.7%和10.1%。（3）NPP变化在中等波动以上（变异系数Cv0.25）的区域所占比例为50.4%。（4）从未来变化趋势看，石羊河流域植被NPP恢复的持续性较弱，呈增加并反持续的地区所占比例达到57.1%。（5）流域的植被NPP变化与气温、降水均成正相关，对气温的响应更为敏感。NPP随海拔高度和坡度增加呈现增大后减小趋势，近年来流域实施的一系列人工造林、退耕还林还草等措施对植被NPP的增加具有明显促进作用。
Abstract: We estimated the vegetation NPP using the CASA model (Carnegie-Ames-Stanford Approach) in the Shiyang River Basin from 2000 to 2020 and analyzed the temporal and spatial variations, stability, and the future change trends of NPP. The influencing factors were also studied from three aspects, namely climate factors, topographic factors, and human activities. The results showed the following: (1) The average vegetation NPP in Shiyang River from 2000 to 2020 was 291.01 g C m- 2 a- 1 and the increase was insignificant. The spatial distribution of vegetation NPP was generally high in the south and low in the north. (2) The proportion of the area of vegetation NPP increased by 86.4% since 2000. The proportions which were extremely significant increased significantly increased were 6.7% and 10.1%, respectively. (3) The proportion of the area where the change in vegetation NPP was moderately above a fluctuation degree [coefficient of variation (Cv) 0.25] was 50.4%. (4) The future change trend indicated that the ability for vegetation NPP to continuously improve was weak, and the proportion of the area where the vegetation NPP had increased but could be reversed in the future was 57.1%. (5) The vegetation NPP was positively correlated with temperature and precipitation, but it was more sensitive to temperature. With increasing elevation and slope, the vegetation NPP first increased and then decreased. Artificial afforestation and returning farmland to forest and grassland significantly improved the vegetation NPP in recent years.