Analysis Of The Response Of Vegetabation NDVI On The Mongilian Plateau To Land Water Store

Water is an important prerequisite for maintaining the growth of vegetation.water availability regulates the growth of vegetation and strongly affects the global carbon cycle.On the other hand,vegetation,as an important part of the terrestrial ecosystem,has the role of connecting ecological elements such as the atmosphere,soil,and hydrology,and plays an important role in regulating water balance on a regional and global scale.Therefore,clarifying the interaction between land water storage and vegetation greenness is particularly important for predicting the future carbon cycle and water cycle,and can provide a scientific basis for regional ecological environmental protection and sustainable development.Based on GIMMS NDVI and GRACE TWSA remote sensing data,this study uses Theil-Sen trend analysis and MK trend test to analyze the spatiotemporal characteristics of vegetation TWSA and NDVI in the Mongolian Plateau.Correlation analysis is used to explore the correlation between the two,and autoregressive model is used to quantify the response of the vegetation ecosystem stability of the Mongolian Plateau to the short-term anomalies of terrestrial water storage anomaly(TWSA)from 2002 to 2015.The main conclusions are as follows:(1)Based on GRACE\TWSA remote sensing data,using Theil-Sen trend analysis and MK trend test to analyze the spatio-temporal change characteristics of vegetation TWSA on the Mongolian Plateau,the results show that the overall TWSA shows a significant downward trend,with a multi-year change rate of 0.715 mm/a(P<0.05).The overall distribution of TWSA shows a decreasing trend from north to south and from northeast to southwest,and shows a relatively high TWSA on the periphery of the plateau,while a relatively low spatial pattern within the plateau.The slope of vegetation TWSA change is stable between-1.55 and 1.42.The TWSA in the study area as a whole shows an increasing trend of the area accounted for45.30% of the total area,of which the significantly increased area accounted for 31.49% of the total area(p<0.05),mainly distributed in Kent Mountain and the Daxinganling Mountains in the east.(2)Based on GIMMS NDVI remote sensing data,using Theil-Sen trend analysis and MK trend test to analyze the spatio-temporal changes of vegetation NDVI in the Mongolian Plateau,the results show that the average annual NDVI value of vegetation in the Mongolian Plateau during the growing season from 2002 to 2015 is 0.26?0.32,As a whole,there is an upward trend of volatility,with a growth rate of 0.02%/10 a,and individual inter-annual changes are relatively volatile.In terms of spatial distribution,it shows strong characteristics of difference,and the overall distribution is zonal decreasing from northeast to southwest.The low-value areas of NDVI are mainly distributed in the Alxa Desert in the southwest.Due to the harsh natural environment in these areas,the NDVI is relatively low.The high value areas are mainly distributed in the forest area and meadow grassland area in the northeast of the Mongolian Plateau.The change trend of vegetation NDVI in the Mongolian Plateau shows obvious regional spatial differences,and the slope of vegetation NDVI change is stable between-0.002 and 0.003.The TWSA area in the study area as a whole showed an increasing trend,accounting for 71.89% of the total area,of which the significantly increased area accounted for 35.49% of the total area(p<0.05).(3)Using Pearson correlation analysis method to analyze the correlation between TWSA and NDVI on the Mongolian Plateau from 2002 to 2015,the results show that the correlation coefficient between vegetation NDVI and TWSA is-0.40?0.70,and the area where vegetation NDVI and TWSA are positively correlated accounts for the total area 75% of the total area is mainly distributed in the central Mongolia and other regions of the Mongolian Plateau;the negatively correlated area accounts for 25% of the total area,mainly distributed in the southern and northwestern regions of the study area.Significant T test was performed on the correlation coefficient between TWSA and vegetation NDVI,50% of the correlation coefficient of TWSA passed the P<0.05 level test,and the significant correlation area was mainly distributed in the central abdomen area of the study area.(4)The autoregressive model was used to quantify the response of the vegetation ecosystem stability of the Mongolian Plateau to the short-term anomaly of terrestrial water storage anomaly(TWSA)from 2002 to 2015.The results showed that 99.2% of the vegetation pixels in the study area showed strong restoration the regions with strong resilience stability are distributed in the northeastern and northern Mongolian plateau and central Inner Mongolia.Woodlands,meadow grasslands,and typical grasslands all show strong resilience stability.Most parts of the study area showed insignificant stability of resistance to TWSA,only 33.1% of vegetation pixels showed remarkable stability of resistance to TWSA.Areas with significant stability of vegetation resistance were mainly distributed in the middle and east of the Mongolian Plateau and the typical grassland and desert grassland areas in the northwest.