| Drought,as a common natural disaster with a large impact,has great damage to regional environment,ecological quality,crop growth and development,and many regions in China also show an increasing trend of drought.Due to the deepening integration of 3S technology and drought monitoring,the analysis of agricultural drought has a new and efficient technical way.Based on the special geographical and drought conditions in northwest Liaoning,this paper realizes dynamic monitoring and drought analysis in the arid city agglomeration.Based on the precipitation data of northwest Liaoning from 2001 to 2020,in2002,2009,2009 and 2019,the remote sensing data of four sequences are used to construct Ts-NDVI index model to analyze the temporal distribution of drought,and use the landscape pattern index with ecological significance to analyze the influence of drought degree on the evolution and fragmentation structure of cultivated land.The main research content of this paper is as follows:(1)The water condition in northwest Liaoning is poor,and the average annual precipitation is between350 and 700 mm.The spatial and temporal distribution of precipitation is uneven,and the drought is frequent,which directly affects the growth of crops and the distribution of landscape pattern.In 2009,the drought was more serious,and in 2019,the drought eased.The drought level was mainly extreme drought and drought,showing the transition from the central region to the surrounding to drought and then to normal.In 2009,the sum of extremely arid areas was the largest,88.82%,the year of severe drought,followed by 68.26% in 2002,6 6.63% in 2019 and 19.54%,with the lowest drought.(2)Liaoning northwest overall is given priority to with cultivated land,and remain at a certain level for a long time,no obvious fluctuation,farmland patch area is relatively stable,farmland patch density index value is small,that liao northwest landscape mainly cultivated land for the matrix background,most of the farmland is concentrated connectivity is better,it is more suitable for planting food crops and management.Over time,the patch density index of each landscape type remained basically stable,and the fragmentation degree remained largely unchanged.The maximum patch index of cultivated land is much larger than that of other landscapes,mainly because of the existence of cultivated land as the dominant landscape in the research area,with its large patch scale.Next were woodland and grassland landscapes,and the maximum plaque index of all other landscapes was relatively low and all lower than 1.00.Spreading and parallel index(IJI)are between 35-70,can see cultivated land in arid areas many transitional vegetation types subject to water distribution and limit spread and parallel index,spread and parallel index value is generally higher,this is because,as the product of human activities,in high artificial design components,compared to woodland,grassland,rivers and other natural landscape,its form is relatively simple concentration,high connectivity,reflects the results of human intensive management.(3)According to the correlation analysis between TVDI and cultivated land landscape pattern index,the PD index of cultivated land and drought index(P <0.01),and LPI index,and showed significant positive correlation with IJI index.The correlation coefficient R value was below 0.4,which has a weak impact on landscape fragmentation.Based on the same year farmland landscape index and TVDI index distribution characteristics and distribution difference,drought on the farmland landscape fragmentation produced significant damage,directly affect the growth and yield of grain,chaoyang,Huludao,Jinzhou and Fuxin drought,cultivated land spatial and temporal structure changes,the fragmentation degree is higher,and changtu,kangping,library,xinmin less affected by drought,farmland connectivity is better,more conducive to the growth of crops. |
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