The Research Of Information Acquisition And Dynamic Change Of Estuary Wetland Resources

Estuary wetland plays a very important role in regulating climate,conserving water source,maintaining biodiversity and maintaining regional ecosystem balance.Because of the fragility and importance of its ecosystem,estuary wetland has become a hot topic in current wetland research.Inventory is an important basic data for rational utilization,development and protection,planning and management of resources.Due to the poor accessibility and the large changes of annual and seasonal dynamics of estuary wetland,the information about the investigation and research of the estuary wetland resources can not be acquired quickly and accurately.Although the application of remote sensing technology has brought great conveniences to the investigation and identification of estuary wetland resources,different remote sensing information sources have their own advantages and defects.In the study of estuary wetland monitoring,the most commonly used Landsat data is relatively high,but the access period is long(16d).In the cloudy and rainy season,remote sensing data cannot be obtained.MODIS data can make up for this defect.It can realize the real-time monitoring of almost every day in any region of the world.However,the spatial resolution of MODIS data is low(250m-1000m),which can not meet the requirements of high-precision wetland resource monitoring.In this paper,MODIS and Landsat remote sensing data fusion method is used to make full use of their complementary characteristics in time and space resolution to generate time series fusion data,further optimize the extraction method of estuary wetland category information and obtain high-precision estuary wetland resource data.On this basis,this paper takes Panjin City as the research area to access the data of estuary wetland resources by using the investigation method derived from the experiment.Meanwhile,the seasonal and annual dynamic characteristics of estuary wetland in this area will be analyzed.By using the driving force analysis model of the enhanced regression tree(BRT)to quantitatively analyze the driving factors of wetland resources change and by establishing the prediction under different plans,the future change and development trend of estuary wetland resources will be predicted.The theoretical basis for estuary wetland resources protection and pattern optimization will be provided.The main research contents and results of this paper are as follows:1.In order to solve the problem of information acquisition caused by the drastic seasonal changes of estuary wetland,this paper uses MODIS and Landsat data fusion method to obtain high-resolution remote sensing data of estuary wetland resources.The experimental results show that the data fusion of the two data sources can well reflect the correlation of different bands,among which the normalized difference water index(NDWI)has the highest correlation coefficient(0.9678),followed by the green band(0.9630),the near-infrared band(0.9345),and the blue band has the lowest correlation coefficient(0.9018).2.In order to extract the classification information of estuary wetland resources more accurately,this paper uses the maximum likelihood method,supporting vector machine method and regression tree(CART)decision tree method to extract the wetland classification information respectively to get the final classification map of estuary wetland and to evaluate the accuracy according to the field survey and high-resolution image.The results show that the overall accuracy of cart decision tree method is more than 2% higher than that of maximum likelihood method and supporting vector machine method,in which the mapping accuracy of swamp wetland is more than 90%,and that of paddy field,river and beach wetland is more than 98%.3.By using data fusion method and category extraction method,the remote sensing data of 6 months in the study area during the wet season and the category time series data of 10 periods are obtained,and then the seasonal and annual changes of the wetland resources in Panjin City are studied.The results show that the seasonal variation of estuary wetland in the study area is intense,and the vegetation coverage is the highest in September.At this time,the remote sensing image is conducive to the information extraction of aquatic vegetation in estuary wetland,and it can reduce the interference of water on the information extraction of paddy field,swamp wetland and other categories.At the same time,the results show that there are significant differences among different types of estuary wetland in the annual changes.From 1998 to 2016,the degree of landscape fragmentation of natural wetland increased year by year,and the connectivity continued to decline,resulting in the gradual decline of wetland ecological function.4.BRT model was used to analyze the relative contribution rate of 14 factors to the change of Panjin estuary wetland.The results showed that the social and economic factors had the greatest impact on the change of Panjin estuary wetland,among which agricultural production had the greatest impact and the contribution rate of agricultural irrigation area was 30.15%,followed by the first industry 10.9% and the second industry 10.59% and the population 9.63%.Relatively speaking,the influence of natural factors on the change of estuary wetland is weak.The sum of annual precipitation,sunshine and average temperature only accounts for 5.58%.5.By using the CLUE-S model,the future changes of wetland resources in Panjin estuary have been predicted and simulated.The results show that according to the historical plan,the patch area is gradually reduced to 78330.8ha in 2035,decreasing by 4.54%,which is mainly caused by the continuous expansion of construction land.According to the ecological plan,by strengthening the protection of wetland resources,the wetland area will reach 83189.8ha,with an increase by 1.40%,mainly resulting from returning farmland to wet.The analysis of landscape pattern shows that according to the ecological plan,the area of estuary wetland has increased slightly.The regional landscape pattern has developed to the direction of homogenization,and the pattern has been continuously optimized.6.Based on the driving force and development trend of wetland change,this paper puts forward the measures for the sustainable utilization of wetland resources in Panjin estuary,including the effective protection of wetland resources in the estuary,the vigorous development of ecological agriculture,the development of natural wetland ecological restoration,the enhancement of wetland pollution control,the rational development of wetland tourism resources,and the improvement of wetland ecological benefit compensation mechanism.