Spatial-temporal variation of satellite-based gross primary production estimation in wheat-maize rotation area during 2000–2015

North China Plain is the largest agricultural production center in China and wheat-maize rotation is a widespread cultivation practice in this area. As gross primary production (GPP) is a proxy of land productivity, research on its spatial-temporal dynamics helps understand the variation of grain production in wheat-maize rotation. Here, Moderate Resolution Imaging Spectroradiometer (MODIS) data and ground observation data were combined to drive Vegetation Photosynthesis Model (VPM) in GPP estimation over wheat-maize rotation area during 2000–2015. Annual GPP has increased by 540.95 g C m−2 year−1 from 2000 to 2015, while total annual GPP has grown ∼150% than that of 2000. Moreover, annual GPP showed an increasing trend in the consecutively wheat-maize rotation area between 2000 and 2015. A strong linear relationship between GPP estimates and grain production demonstrated the potential of using VPM model to evaluate grain production in wheat-maize rotation area of Henan province, China.华北平原是中国最大的农业生产中心，小麦-玉米轮作是该区域广泛采用的种植模式。总初级生产力（Gross Primary Production, GPP）是表征土地生产力的关键指标，对其时空动态开展研究有助于明晰小麦-玉米轮作区粮食生产的变化规律。本研究结合中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS）数据与地面观测数据，驱动植被光合模型（Vegetation Photosynthesis Model, VPM），对2000—2015年华北平原小麦-玉米轮作区的总初级生产力进行估算。2000至2015年间，年均总初级生产力提升了540.95 g C m⁻²·a⁻¹，研究区年度总初级生产力较2000年增长约150%。此外，2000—2015年连续小麦-玉米轮作区的年均总初级生产力呈持续上升趋势。总初级生产力估算值与粮食产量之间存在显著线性相关关系，证实了利用VPM模型评估中国河南省小麦-玉米轮作区粮食产量的应用潜力。