内蒙古不同类型草地NPP时空动态特征及其气候影响因素分析

Analysis on spatial-temporal dynamics of different types grassland NPP and its climate influencing factors in Inner Mongolia

为揭示内蒙古不同类型草地净初级生产力(NPP)时空动态,探究其与气候因子的相关性,利用2001～2016年遥感数据,气象数据和20世纪80年代中国草地分类数据,采用光能利用率(CASA)模型,模拟获取2001～2016年内蒙古草地NPP,并分析了不同类型草地NPP的时空动态及其对气候因子的响应。结果表明:(1)2001～2016年,内蒙古草地年均NPP为163.9 gC/(m^2·a),空间上呈现东北部高西南部低的特征,年均NPP总量为31.6 TgC/a(1Tg=10^(12)g);(2)试验的16年,内蒙古草地年均NPP呈增加趋势增加量为2.1 gC/(m^2·a),年际波动较大;(3)温性草甸草原、热性草丛、低地草甸、山地草甸和沼泽的年均NPP呈显著增加趋势,其他5类呈显著减少趋势;(4)NPP与年均温和年总降水量的相关系数分别为-0.01和0.4;(5)除温性荒漠草原和温性草原化荒漠外,其他类型草地NPP均与温度呈负相关关系,所有类型草地NPP与降水量均呈正相关关系。降水是影响内蒙古草地NPP最主要的气候因子。

In order to reveal the spatio-temporal dynamics of different types grassland net primary productivity(NPP) in Inner Mongolia,and explore the correlation between NPP and climate factors,based on remote sensing data,meteorological data and grassland classification data of China in the 1980 s and CASA model,grassland NPP in Inner Mongolia from 2001 to 2016 was simulated,and the spatial and temporal dynamics of NPP in different grasslands and its response to climate factors were analyzed.The results showed that:(1) From 2001 to 2016,the mean annual NPP of grassland in Inner Mongolia was 163.9 gC/(m^2·a),which was higher in the northeast and lower in the southwest.The total annual NPP was 31.6 TgC a-1(1 Tg = 1012 g),(2) In the past 16 years,the mean annual NPP of grassland in Inner Mongolia showed an increasing trend,with a growth rate of 2.1 gC/(m^2·a),and the annual fluctuation was large,(3) The mean annual NPP of temperate meadow grassland,thermal grassland,lowland meadow,mountainous meadow and swamp increased significantly,while the other five types decreased,(4) The correlation coefficients of NPP with mean annual temperature and total annual precipitation are-0.01 and 0.4,respectively and(5) Except for the temperate desert steppe and the temperate steppe desert,the NPP of other grasslands was negatively correlated with temperature,and the NPP of all grasslands was positively correlated with precipitation.Precipitation was the most important hydrothermal factor affecting NPP in Inner Mongolia grassland.