内蒙古草原生产力与气候变化关系及公元1-2000年ANPP的重建

发布时间：2018-11-07 11:53

【摘要】：草原是生态系统的重要组成部分,植被地上净初级生产力(ANPP)是表征陆地生态过程的重要参数,对了解全球碳平衡有着重要作用。草原生产力强烈地依赖自然环境和气候变化,目前我们对千年尺度上的草地生产力变化的认识几乎是空白。本文利用近60a年的实测气象资料及公元1-2000年重建的高精度历史气候资料,基于一些假设条件的前提,选取海拉尔、锡林浩特、百灵庙作为草甸草原、典型草原和荒漠草原的代表站点,借助CENTURY模型重建了公元1-2000年内蒙古不同草原生产力的序列,在此基础上,综合应用Pearson相关、连续小波和交叉小波等统计方法,探讨不同草原ANPP的周期特征及其与温度、降水量之间关系,分析ANPP时空分布特征,得到的主要结论如下:1)利用1982-2006年卫星资料反演的草原年均NDVI和气象数据,CENTURY模型模拟草甸草原、典型草原、荒漠草原ANPP与同期NDVI有很好的一致性,通过了 99%的信度水平检验,表明CENTURY模型能够很好反映ANPP的变化特征。2)近60a内蒙古草甸草原、典型草原、荒漠草原气候均呈现出增温的趋势。3类草原ANPP年际波动显著,与典型草原有轻微下降趋势不同,草甸和荒漠草原有轻微上升趋势。典型草原ANPP波动幅度最大,荒漠草原次之,草甸草原最小;草甸草原生产力最高,荒漠草原最低,典型草原居中。3类草原草原ANPP存在准3～5a显著振荡周期,典型草原ANPP还存在准7a显著振荡周期,荒漠草原ANPP还存在准9a的振荡周期。草甸草原ANPP主要受温度控制,温度越高,ANPP越大,典型草原和荒漠草原主要受降水控制,升温不利于ANPP的增加,3)重建所得公元1-2000年内蒙古草甸草原、典型草原和荒漠草原ANPP长期波动大体相似,其中在魏晋和明清小冰期有明显的低值阶段,公元600-1200年为高值期。ANPP均具有显著的周期特性,草甸草原ANPP有准300a、准150a和准50a显著周期,典型草原ANPP有准280a和准64a显著周期,荒漠草原ANPP有准256a和64a显著周期。降水和温度对草原生产力有重大影响,但在对不同类型的草原影响有所不同。典型草原和荒漠草原主要受降水控制,草甸草原受降水和温度共同控制。4)内蒙古草原区1-2000年ANPP均值存在明显的空间差异,自东向西呈现为不规则带状格局。2000年ANPP均值分布图中,ANPP大于140gC/m2、大于80小于140gC/m2、小于80gC/m2区域分别与草甸、典型和荒漠草原区相对应。相比2000年ANPP均值分布,暖期草甸草原面积普遍增加,冷期草甸和典型草原面积的显著减少。温暖湿润的气候会使得荒漠草原转变为典型草原或草甸草原;干燥和寒冷的天气会使得草地区域荒漠化,荒漠草原面积增加。以上研究结果将有助于在更长时间尺度内了解全球碳循环、草原游牧民族各部落畜牧经济的变化以及合理开发利用草原自然资源提供理论支撑。
[Abstract]:Grassland is an important part of ecosystem. (ANPP) is an important parameter to characterize terrestrial ecological process and plays an important role in understanding the global carbon balance. Grassland productivity strongly depends on natural environment and climate change. At present, our understanding of grassland productivity change on millennium scale is almost blank. In this paper, the Hailar, Xilinhaote and Bailingmiao are selected as meadow grasslands based on the measured meteorological data of nearly 60 years and the high-precision historical and climatic data reconstructed from 1-2000 AD, based on some hypothetical conditions. The representative sites of typical steppe and desert steppe have reconstructed the sequences of different grassland productivity in Inner Mongolia from 1 to 2000 AD with the help of CENTURY model. On this basis, the statistical methods such as Pearson correlation, continuous wavelet and cross wavelet are used synthetically. This paper discusses the periodic characteristics of ANPP in different steppe and its relationship with temperature and precipitation, and analyzes the spatial and temporal distribution of ANPP. The main conclusions are as follows: 1) the average annual NDVI and meteorological data of steppe retrieved by satellite data from 1982 to 2006; CENTURY model can simulate meadow steppe, typical steppe and desert steppe have good consistency with NDVI in the same period. The reliability level test of 99% indicates that CENTURY model can well reflect the change characteristic of ANPP. 2) Inner Mongolia meadow steppe in recent 60 years. The climate of typical steppe and desert steppe showed a trend of increasing temperature. The interannual fluctuation of ANPP of three steppe was significant, which was different from that of typical steppe, and that of meadow and desert steppe increased slightly. The range of ANPP fluctuation in typical steppe was the largest, followed by desert steppe and meadow steppe. The productivity of meadow steppe is the highest, the desert steppe is the lowest, and the typical steppe is in the middle. The three types of steppe ANPP have quasi-3 ~ 5 years significant oscillation period, typical steppe ANPP has a quasi-7 year notable oscillation period, and the desert steppe ANPP also has a quasi-9 year oscillation period. The ANPP of meadow steppe is mainly controlled by temperature, the higher the temperature is, the larger the ANPP is. The typical steppe and desert steppe are mainly controlled by precipitation, and the increase of temperature is not conducive to the increase of ANPP. The long-term fluctuation of ANPP in typical steppe and desert steppe was similar, among which there was a low value stage in the small ice age of Wei, Jin and Ming and Qing dynasties, and a high value period in 600-1200 AD. ANPP had significant periodic characteristics, and ANPP in meadow steppe had quasi-300a. The typical grassland ANPP has a quasi-280a and quasi-64a significant cycles, and the desert steppe ANPP has a quasi-256a and 64a significant cycles. Precipitation and temperature have great influence on grassland productivity, but have different effects on different types of grassland. The typical steppe and desert steppe are mainly controlled by precipitation, while the meadow steppe is controlled by precipitation and temperature. 4) there is a significant spatial difference in the mean value of ANPP between 1-2000 years in Inner Mongolia steppe. From east to west, an irregular zonal pattern appeared. In the mean value distribution of ANPP in 2000, ANPP was greater than 140 g C / m 2, more than 80 < 140 g C / m 2, and smaller than 80gC/m2 area corresponding to meadow, typical and desert grassland respectively. Compared with the mean distribution of ANPP in 2000, the grassland area of meadow in warm period generally increased, and the meadow and typical grassland area in cold period decreased significantly. The warm and humid climate will change the desert steppe into typical steppe or meadow steppe; the dry and cold weather will make the grassland area desertification and increase the desert grassland area. The above results will be helpful to understand the global carbon cycle in a longer time scale, to provide theoretical support for the changes of pastoral economy of nomadic tribes and the rational exploitation and utilization of grassland natural resources.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812

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