内蒙古温带典型草原返青期变化对生长率的时空影响研究

This proposal aims to investigate the spatial and temporal impacts of green up changes on growth rate in typical steppe of Inner Mongolia, integrating ecological in-suit and ground spectrum measurement techniques, multi-temporal remote sensing images, GIS and global position system. Besides, land use type maps, vegetation type maps and meteorological data are also considered as supporting data sources. A new method monitoring green up of typical steppe will be developed to improve the traditional ones combining field survey and remote sensing inversion. In order to study multi-year changes of above-ground and under-ground accumulated growth rate of different grassland communities, the proposal will reform and construct a growth rate monitoring model suitable for typical steppe in Inner Mongolia driven by multi-temporal remote sensing data. Then, couple the remote sensing extraction model of vegetation green up with vegetation growth rate model and develop a new monitoring model revealing the response of vegetation growth rate on vegetation green up changes. With the models above, the proposal will achieve the response of multi-year growth rate changes on green up of typical steppe in regional scale. A thorough investigation of the influence of the advance or delay of green up on grassland growth rate is very important to scientific management and utilization of grassland, and will supply essential basis for sustainable development of animal husbandry on typical steppe.

利用土地利用类型图、植被类型图和气象数据等辅助资料，在生态学野外测量技术、地面光谱测量技术，多时相遥感影像、地理信息系统、全球定位系统的综合支持下，结合地面观测与遥感反演，改善传统的草原返青期模拟方法，发展草原返青期模拟新方法。集成基于多时相遥感数据驱动的生长率模拟模型，发展和完善适用于内蒙古典型草原的生长率模拟模型，研究多年的不同草原群落的地上和地下累积生长速率的变化；耦合植物物候的遥感提取模型与植被生长率模型，发展植被生长率对植物物候的响应模拟模型，研究区域尺度多年典型草原生长速率变化对草原返青期的响应。深入研究草原返青期提前或推迟对草原生长率的影响，为科学地管理和利用草地，实现草地畜牧业的可持续发展提供重要的科学依据。

本研究选取内蒙古三种不同类型草原进行研究，在生态学野外测量技术、地面光谱测量技术，全球定位技术、地理信息系统技术的综合支持下，利用多时相遥感数据、气候数据、土壤数据、植被类型数据、结合了草地生长特性，提出了一种改进的动态阈值法来模拟草地返青期，并分析了内蒙古温带草原2001-2015年牧草返青日期的空间变化规律；分析了返青期和地表温度关系研究；通过耦合植物物候遥感提取模型与植物生长率模型，得到一种植被生长率对植物物候的响应模拟模型，并证实牧草返青日期不同对该模型模拟精度具有一定的影响；在控制每年牧草返青后气温、降水相同的情况下，分析了在长时间序列上返青日期变化对牧草旬生长速率、月生长速率的影响，发现大部分旬牧草生长率受返青期变化影响显著。