| Climate warming has already had an important impact on terrestrial ecosystem-related processes and has become an important part of the study of carbon cycling in terrestrial ecosystems.In the face of large-scale grass pasture production estimation,remote sensing monitoring has become the most common and fastest advanced method.As the most sensitive area of the ecosystem in China,Sanjiangyuan Nature Reserve in China has been used to estimate pasture biomass and its related factors by using remote sensing methods,which is of great significance to the sustainable utilization of grassland resources and the development of animal husbandry.Based on remote sensing and meteorological data,the paper uses remote sensing and meteorological data to estimate grassland grassland production in the study area,and analyzes the trends and abrupt changes of six meteorological factors.The impact of changes in meteorological factors on grassland volume is as follows:(1)Based on the improved CASA model for different types of natural pastures in the study area,using 2000-2010 MODIS vegetation remote sensing product data and precipitation and temperature data for the annual growing season from April to September,and using ArcGIS software to establish grassland grass production.Satellite remote sensing estimation model.The experiment shows that the yield per year of the grassland in the study area is 160～180kg between the lake,the beach and the meadow,and the overall trend is slightly higher.The yield of the sparse forest in the mountainous area is between 130-160kg,and the overall trend is slightly reduced;mountain irrigation Grass yield per mu is between 128～160kg,and grass yield is not stable;alpine meadow is between 110～130kg and plateau grassland is between 70～80kg.The overall trend is relatively stable;mountain grassland is between 48～56kg.Plateau wide desert is between 39～45kg,and mountain desert is between 40～50kg.The overall trend is very stable.Spatially,there is an overall gradual decline from southeast to northwest,in which alpine meadow grassland and highland wide grassland grassland dominate;(2)Using the Mann-Kendall model to calculate the trend and abrupt change trend of meteorological factors such as average temperature,average minimum temperature,average maximum temperature,sunshine duration,precipitation,and average relative humidity in the study area weather station for more than sixty years The dynamic changes of various meteorological factors were analyzed.The results showed that the temperature factors in the study area as a whole showed a significant upward trend.The most significant areas of upward trend were concentrated in the southern and southwestern grasslands of the study area,especially the areas with an average temperature factor of more than half had an upward trend of more than 99%.The significance level reflects the global warming trend;the overall trend of the sunshine hours factor and precipitation factor is not obvious,showing a relatively stable trend;the average relative humidity factor as a whole is a significant downward trend,more than 90%.The regional decline trend exceeds the 90%significance level;(3)Using the grey correlation method,the correlation between meteorological factors and grass yield was calculated based on the grassland grass production and relevant weather factor data in the study area from 2000-2010.The results showed that the correlations of the six meteorological factors and grass yields from large to small were average relative humidity,average maximum temperature,average temperature,sunshine hours,precipitation and average minimum temperature,of which the first four were the most significant,and the correlation was 0.8.Left and right,the last two correlations are between 0.65～0.7.In summary,this study has important guiding significance for rapid monitoring and protection of grassland production in grasslands of Sanjiangyuan Nature Reserve. |
