Spatio-Temporal Change Remote Sense Monitoring And Analysis Of Surface Water Resources In Five Countries Of Central Asia

The five countries of Central Asia,including Kazakhstan,Tajikistan,Kyrgyzstan,Uzbekistan,and Turkmenistan,are the typical vulnerable and sensitive ecological area of the world.Water resources play a vital role in the development of social and economic and maintaining the balance of the regional ecosystem in the arid region.But the vast majority of the water resources actually available in the five Central Asian countries are surface water,and the contradiction between water resources is very prominent.Affected by global climate change and human activities,it has triggered a series of environmental problems,such as soil salinization,land desertification,desert ecosystem vegetation degradation,water shortage,and water pollution.In order to reveal the temporal and spatial variation characteristics and their influencing factors of the surface water of the five countries of Central Asian,bases on the long-term remote sensing data MOD44W and JRC global surface water data-set from 2001 to 2015,this paper achieves the extraction of information,dynamic change characteristics and transfer rules of surface water in the five countries of Central Asia by spatial statistical method.And the dynamic changes of land use and landscape pattern in the study area in the past 15years were analyzed.Combined with the correlation model and method,the influence factors of surface water were also analyzed from the three aspects of geographical environment,climate change and human activities.Main works and conclusions of this paper are listed as follows:(1)After investigating the temporal and spatial variation characteristics of the surface water index of the five Central Asian countries in the past 15 years,we can see that:1)The spatial distribution of surface water area in the five Central Asian countries has gradually increased from south to north,and the characteristics of surface water,which is more intensive in the northern than southern,are very obvious.The change trend of surface water area is generally declining.A total of 15263.1875 km~2was reduced during the year.2)Kazakhstan is the country with the largest surface water area in the five Central Asian countries.In the past 15 years,the surface water area has reduced in general,and the most severe region of surface water reduction includes Qyzylorda,Mangghystau and Atyrau.Surface water area in Uzbekistan changes in the past 15 years also showed a decreasing trend.Due to the greater degradation of the East Aral Sea area,the surface water area of Karakalpakstan Republic decreased the most intensive.And The surface water area of Turkmenistan,Kyrgyzstan and Tajikistan has not changed much in this 15years.3)The surface water area of the Balkhash-Ala Lake Basin,the Amu River Basin and the Syr River Basin are all increasing,and the total surface water area is greatly affected by the seasonal water area change.The seasonal water area changes in most years.The amplitude is greater than the change in permanent water area,while the area of the Aral Sea is greatly affected by the permanent water area.(2)After studying the temporal and spatial variation characteristics of land use/cover and landscape pattern in the five countries of Central Asia in the past 15 years,it is known that:1)The main land use/cover types of the five Central Asian countries are grassland and unused land,and the artificial surface area is the least,but the artificial surface area of each country is increasing.The cultivated land in Kazakhstan has been reduced overall,and the cultivated land of the remaining four countries has shown a growth state.For natural vegetation,the forest land is growing,while the grassland is decreasing overall,and the unused land shows a growth trend.The overall landscape pattern of the five Central Asian countries is becoming more and more fragmented,and the impact of human activities on landscape patches is gradually strengthening.2)Both the cultivated land and man-made land in the Amu River are growing.The artificial surface area of the Balkhash-Ala Lake Basin and the Syr River is increasing year by year,while the cultivated land area is decreasing.The grass area of the Amu River Basin and the Syr River Basin The area of unused land has increased,while the grassland area in the Balkhash-Ala Lake Basin has increased while the unused land has decreased.The landscape pattern changes in the Amu River Basin and the Syr River Basin are consistent with the whole,while the complexity of the landscape pattern in the Balkhash-Ala Lake Basin is gradually reduced.(3)Analysis of the influencing factors on the surface water bodies of the five Central Asian countries:1)The distribution of surface water bodies in the first-level elevation(<0m)and the second-level elevation(0-50m)of the study area accounts for a large proportion,and the inter-annual variation of surface waters in the second-level elevation is too large.The weighted shape index of unused land,forest land and unused land area is highly negatively correlated with surface water area(correlation coefficient is greater than 0.9),and grassland area is highly positively correlated with surface water area.2)The annual precipitation and annual average temperature in the study area are increasing,which will inevitably increase the regional precipitation and glacial meltwater,thereby increasing the regional surface water supply,which is related to the Amu River Basin and the Syr River Basin.The increase in water area is in line with the trend.3)The population and gross national product of Kazakhstan,Uzbekistan and Turkmenistan are highly correlated with the surface water area.There is no significant correlation between the population and gross national product of the two mountainous countries of Kyrgyzstan and Tajikistan and the surface water area.This shows that the impact of human activities on surface water in the five domestic water-using countries is more significant than that in water-producing countries.