| 徐茜,杨忍,任志远.黄土高原地区NPP的自然影响因素分析[J].干旱地区农业研究,2016,34(4):244~250 |
| 黄土高原地区NPP的自然影响因素分析 |
| Analysis on the natural factors affecting NPP in Loess Plateau |
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| DOI：10.7606/j.issn.1000-7601.2016.04.37 |
| 中文关键词: NPP CASA模型 自然影响因素 黄土高原 |
| 英文关键词:NPP substance CASA model the natural influence factors Loess Plateau |
| 基金项目:国家自然科学基金项目(41401190) |
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| 中文摘要: |
| 以SPOT NDVI和多种自然地理要素数据为基础，利用改进光能利用率计量模型，探究影响净第一性生产力(NPP)变化的自然因素差异及各地貌类型区NPP变化的主导影响因素。结果表明：① 1998—2010年黄土高原地区NPP物质量平均值为9.884～50.790 gC·m-2·a-1，明显低于全国平均水平342 gC·m-2·a-1。② 影响NPP变化的自然因素差异显著。台塬区保水性好，水土流失强度较低，NPP物质量增加显著，风蚀地貌区NPP水平低，降幅明显；干湿条件是影响NPP变化的重要自然要素，半湿润区NPP增幅量较大；坡度对NPP变化的影响显著，陡坡区林、草植被覆盖度增加，NPP增幅明显；微观尺度上水热空间分布与海拔高度相关，研究区海拔200～1 000 m范围NPP增幅显著，海拔高于1 000 m的区域NPP呈下降趋势。③ 影响NPP空间分布格局差异的主导因素为水热条件，但决定黄土粱卯地貌类型区的NPP物质量水平正相关的主导因素为高程因子，0.01置信水平下相关系数为0.52；太阳辐射对NPP物质量表现为显著负相关关系，尤其对气候干旱区域表现突出。 |
| 英文摘要: |
| This study explored differences of natural factors that affected NPP and the driving factors of NPP, which was based on a variety of data of natural geographical elements including the type of land-forms, and SPOT NDVI using a modified light use efficiency model. The study showed that from 1998 to 2010, the mean value of NPP substance changed from 9.884 gC·m-2·a-1 to 50.790 gC·m-2·a-1 in the Loess Plateau region. The value was lower than the national average level which was 342 gC·m-2·a-1. In addition, natural factors that affected the changes of NPP showed significant differences. The loess platform had high water retention, low water loss and soil erosion intensity, such that NPP substance became increased significantly. NPP was maintained at a relatively low level and was dropped significantly in wind erosion landform areas. Dry and wet conditions were important natural elements which affected the changes of NPP. NPP increase amount was much bigger in semi-humid zone than others. Slope had significantly effects on NPP changes. With the increase of vegetation coverage in steep slope areas, NPP was obviously increased. Within micro scales, heat water spatial distribution was found to be related with the elevation. In the study areas, NPP was significantly increased at altitude from 200 m to 1 000 m. However, NPP was shown to become declined when altitude was over 1 000 m. Furthermore, the dominant factor which affected the differences of NPP special distribution was hydro-thermal condition. But the main effect factor of NPP substance based on loess ridge and loess hill was altitude. Its correlation coefficient was 0.52, under the 0.01 confidence level. There was a significant negative correlation between solar radiation and NPP, which was particularly apparent in arid region. |
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