Gong Zhaoning

Using RS and GIS to monitoring Beijing wetland resources evolution

In Beijing, Wetlands have been playing a crucial role in conserving municipal freshwater and retaining biodiversity. The classification system of Beijing wetland has been set up. The interpretation keys of six main wetland types in Beijing, including River, Reservoir, City Lake, Artificial Canal, Pound and Paddy Field, were built up using TM/ETM+ multi-spectral pseudo-color composition images as the data source. The modern information technology such as RS, GIS and GPS is combined with field investigation for further analysis to obtain the historical change information of wetland area, water quality and landscape pattern, The wetland soil and plant distribution maps in different large scale were sketched, and their attribute databases including hydrology, soil and plant were built up also. From which, its trend of evolution and some driving factors are analyzed successfully. This study indicates that not only have wetland areas been reduced by half, but also their ecological environments have been degraded because of rapid economic development and population increase. Suggestions based on this research are made to reconstruct the ecological environment of the wetlands and return them to their previous state.

A study on optical and SAR data fusion for extracting flooded area

This article proposes a method of fusing the optical data before the flood and SAR (synthetic aperture radar) data during the flood. The main goal of this study is to evaluate the capability of data fusion to combine the information from Landsat ETM image with Radarsat SAR image for water body and flooded area extraction. The Landsat ETM data will basically provide the information of landform and background information which includes the normal water extent. The Radarsat SAR data however was taken during flood will provide information mainly on water body extent and flooded area. In the result image, flooded area was significantly enhanced. We can distinguish the flooded area and normal water area easily.

Remote sensing applications: Ecological environment effect analysis of Widgeon Lake Wetland change in Beijing region

Using Landsat TM and ETM+ images from 1984 to 2004, this paper analyzed the hydrology, soil, plant condition of the Widgeon Lake Wetland in Beijing. And the results are as follows: Salinized area had increased every year and reached to a head in 2004. Due to the soil salinization, the marsh vegetation species changed to the mesophytic, xeromorphic and salt tolerable ones. Along with the continuously shrinking of water area, wetland dominated the low coverage. The cold-humid effect of wetland had been impaired for the breakage of wetland environment in recent years. The decrease amount of regional daily evapotranspiration proved that the climate was drying and warming. The regional ecological negative effects were closely connected with the decrease of wetland resources. We should bring forward corresponding effective protection and utilization measures and give the scientific basis for the restoration of wetland resources.

Three dimensional groundwater virtual reality system and its spatial database

The current policy in the work of groundwater exploitation and management was paying attention to the questions of overall situation, long-term requirement and the holistic development of hydrological geology. Under this framework, the work of groundwater scientific management had some new characteristics. The outstanding representation was the combination with spatial information technology and virtual reality technology. Our research work was founded on the basis of field monitoring and surveying. To correctly reveal and express the actual spatial structure of groundwater and its storage environment, by using stratum generalization, spatial analysis, data interpolation and some other methodologies, a suit of 3D data structure was designed out and realized by C++ programming language to store and express the underground spatial information. Based on the database technology, an independent 3D spatial data engine interfaces was developed to make the following works more convenient. Taking the 3D virtual demonstration, arbitrary section analysis, dynamic changing simulation, and land subsidence simulation as the main objectives of developing, an integrated 3D groundwater virtual reality system (TDGVRS) was accomplished. We selected visual C++ as the main programming tool and OpenGL as the 3D graphic rendering tool. Now, the system is practically running in some operational departments. Feedbacks from the user show that the effect of visualization was good, the operation is flexible, the analysis functions are powerful and the result is credible. TDGVRS is now providing important technical supports to relative groundwater management works.

The temporal-spatial changes on desertification and salination of West Jilin Province based on RS technology

The west of Jilin province lies in the center of Song-liao plain, which was once an important stockbreeding base in the province and one of the perfect natural pastures in China, while now where ecological environment becomes worse and the “Three Deteriorate” are serious. The whole west of Jilin was made in the severe ecological crises because of a lot of factors, such as weather, over-browse, irrational land utilization, and so on, since 1980s. With the problems of “Three Deteriorate” is increasing, which have greatly effected the environment of economic development and people lives. So it has important reference value to control “Three Deteriorate”, and implement specific measures to improve ecological environment. This article applied remote sensing technology to analyze the image information of land desertification in the west of Jilin province in 1980s and in 1990s, and establish all kinds of image interpreted symbols on environmental features such as physiognomy, grass, water system, salina, sand land, vegetation and so on. Based on the different time scale of remote sensing data, linking with the information of the land utilization, vegetation evolvement and climate change currently which investigated on the site, we established basic database of desertification in the west of Jilin province, found out the temporal-spatial distribution rule of “Three Deteriorate” phenomenon by the analysis among different period image information, and made a conclusion on the correlation among the desertification, the salinization and meadow degeneration. Based on the natural situation of West Jilin province, it is essencial to take measures to protect the ecological environment by transfer the water from the north to the south, to improve the cycle between the ground water and surface water, and to accelerate the restoration of wetland resources.

Remote sensing retrieval for chlorophyll-a concentration in seasonal turbid case II water based on baseline correction of spectra

Chlorophyll-a( Chl. a) concentration is an important indicator of water quality evaluation,which is affected by the seasonal changes of suspended matter concentration. How to weaken the spectral interferences of suspended matter is an important issue in the retrieval of Chl. a concentrations with remote sensing in inland water. Based on six field surveys in 2011-2013 in Guishui River,the inversion ability of Chl. a concentrations with three-band model and support vector regression model were evaluated,in which baseline correction and first order differential method were used to weaken the spectral noises. Reflectance of 750 nm was defined as a baseline,a connecting line of reflectance from 500 nm to 750 nm was defined as another baseline. Baseline correction was defined as spectral reflectance minus baseline values. The validation was performed using data of samples in July 2013,the results demonstrated that SVR model was better than the three-band model in reversion of the Chl. a concentration in seasonal turbid water. Band reflectance combinations after baseline correction screening as the input variables can improve the inversion accuracy of the SVR estimation model. The determination coefficient was 0. 68 and the root mean square error was 3. 38 μg / L. Linear baseline correction can slightly improve the inversion accuracy of the three- band model.

Canopy water content estimation for typical emerged plant community from simulation worldview-2 data: A case study in Wild Duck Lake wetland, Beijing

Quantitative estimation of vegetation water content with remote sensing technique is of great significance for vegetation physiological status and growth trend monitoring. It also provides a theoretical foundation for actual application of vegetation water content diagnosis using remote sensing images in Wild Duck Lake wetland. In this paper the NDVIs and SRs calculated from simulation WorldVeiw-2 curves can be used to model and predict canopy water content of typical emerged plant. The NDVIs and SRs involving the additional spectral bands of WorldView-2, such as the red-edge and near infrared regions of the electromagnetic spectrum, improve the prediction accuracy compared with the traditional NDVIs and SRs.

Research on the Land Desertification of Beijing Piedmont Plain Area based on Remote Sensing Technology

As a significant factor restricting the development of Beijing, land desertification has become one of the most serious ecological environmental problems in Beijing. It is considered as an urgent demand to master the formation causes and change trend of land desertification in Beijing. The information of land desertification in Beijing piedmont plain was recognized and extracted from 2007 SPOT5 data. The result shows that Yongding River, Chaobai River, Dasha River, Kangzhuang, Nankou and their surrounding areas are the principal distributing areas. They are all fixed sand areas that mainly contain mild and moderate desertification. From the year 1999 to 2007, the total area of desertificated land in study area has the trend of decrease. However, the phenomenon of destroying at the same time as fathering still exists in some areas.

Research on the landscape change of YeYaHu wetland based on remote sensing fusion

Because of its special resources and function characters, the wetlands are being attached more and more importance. The Yeyahu wetland is a typical artificial wetland in the north China. Its the only natural conservation area in Beijing region. It locates in the northwest Beijing where is the sand storm coming through road. The wetland is the first circle- protection band for Beijing, and is the northwest ecological shelter. But affected by the strong coercion factor, the resources and the structure have changed quietly in resent ten years and it has threatened the healthy development. Using the fusion remote sensing technology with TM and IRS as date resource, the field circumstance monitoring was conducted. By this research, we found the area of the wetland had decreased more than half. Whats more, the environment is tending to be worse. The reasons for wetland dynamics were analyzed. This is the base for wetland protection and restore.

The creation and analysis of riparian buffer zones based on RS and GIS - a case study on Beijing guanting watershed

IEEE, IEEE Geosci & Remote Sensing Soc, NASA, NOAA, USN Off Res, Japan Aerosp Explorat Agcy, Natl Polar orbiting Operat Environm Satellite Syst, Ball Aerosp & Technologies Corp, Int Union Radio Sci, Elect & Telecommun Res Inst, Korea Sci & Engn Fdn, Korea Natl Tourism Org, Korea Telecommun