气候和土地利用变化对成都市植被NPP时空分布的影响

以2001-2010年MOD17A3数据集的年均NPP数据为基础,分析成都市植被净初级生产力的时空变化及其影响因素,并借助回归分析方法对引起植被NPP变化的影响因素进行量化分析.结果表明:研究区植被净初级生产力年际变化特征明显,年净初级生产力分布在560～699gC/(m~2·a)之间,平均值为663gC/(m~2·a),总体来看10年间成都市植被净初级生产力呈波动减少趋势,年际减少为5.04gC/(m~2·a).空间分布上表现为由西南向东北逐渐减少的趋势,不同地形区植被NPP变化程度各异,其中平原区植被NPP下降趋势最为显著,其次为山区,而丘陵区植被NPP呈上升趋势.温度、降水量、耕地面积和建设用地面积对整个成都市植被NPP时空变化的独立解释能力分别为2.3%,16.4%,1.0%,10.5%,即研究区植被NPP受到自然因素和人为因素共同作用,而自然因素对植被NPP时空变化的主控作用总体上大于人为因素.对各地形区而言,山区NPP变化主要受到温度和降水量影响,降水量是主控因素(独立解释能力为6.6%);平原区NPP变化主要受到降水量、耕地面积和建设用地面积影响,建设用地面积为主控因素(独立解释能力为10.3%);丘陵区NPP变化主要受到温度、降水量、建设用地面积影响,建设用地面积为主控因素(独立解释能力为5.2%).研究结果为区域生态环境的建设,以及合理的城市土地利用规划提供依据.

The Effects of Changes in Climate and Land Use on the Spatio-Temporal Distribution of Vegetation NPP in Chengdu

In order to provide a theoretical basis for the construction of regional ecological environment and rational urban land-use planning, this paper analyzes the spatio-temporal variation and its influencing factors for vegetation net primary productivity in Chengdu based on the annual NPP data of MOD17A3 data sets from 2001 to 2010, and conducts a quantitative analysis of the influencing factors causing vegetation NPP variation with the help of the regression analysis method. Results indicate that the annual variation characteristics of vegetation net primary productivity in the research area are obvious, while the annual net primary productivity is distributed in the range of 560 and 699 gC/(m²·a), averaging 663 gC/(m²·a). Overall, in the ten years (2001-2010), the vegetation net primary productivity in Chengdu presented a decreasing tendency, with an annual decrease of 5.04. The spatial distribution of vegetation net primary productivity in Chengdu shows a tendency of gradual decrease from southwest to northeast. The vegetation NPP varies with different morphologic regions. The plain areas show the most obvious decreasing tendency, followed by the mountainous areas, while a rising tendency is present in the hilly areas. Temperature, precipitation, agricultural acreage and construction land area account for 2.3%, 16.4%, 1.0% and 10.5%, respectively, of the vegetation NPP spatio-temporal variation in Chengdu. In other words, the vegetation NPP in the research area is under the combined action of natural factors and artificial factors. As a whole, the main control function of natural factors on vegetation NPP spatio-temporal variation is stronger than artificial factors. NPP variation in mountainous areas is mainly influenced by temperature and precipitation, while precipitation is the main control factor (its independent interpretation ability being 6.8%). NPP variation in plain areas is mainly influenced by precipitation, agricultural acreage and construction land area, while construction land area is the main control factor (its independent interpretation ability being 10.3%). NPP variation in hilly areas is mainly influenced by temperature, precipitation and construction land area, while construction land area is the main control factor (its independent interpretation ability being 5.2%).