Wang Z.,Capital Normal University |
Li X.,Capital Normal University |
Li X.,Urban Environmental Processes and Digital Modeling Laboratory |
Li X.,Laboratory of 3D Information Acquisition and Application |
And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014
In order to take full advantage of the multi-source remote sensing data, the concept of image fusion was proposed and nowadays, many fusion algorithms have been produced, so the adaptability of the algorithm has become a hot topic. This article aiming at the panchromatic and multispectral images of Worldview-2, uses the different fusion methods, including PCA, HPF, Gram-Schmidt and wavelet transform, to fuse the image, and evaluates the results from the aspects of the statistical information, spectral information and spatial characteristics. Then it takes the extracting vegetation as an example, analyzes the applicability of different fusion methods. The research shows that Gram-Schmidt and wavelet transform have better fusion quality and Gram-Schmidt is the most suitable method to extract vegetation for Worldview-2. © 2014 SPIE. Source
Tang L.,Capital Normal University |
Tang L.,Beijing Municipal Key Laboratory of Resources Environment |
Hu D.,Capital Normal University |
Hu D.,Beijing Municipal Key Laboratory of Resources Environment |
And 2 more authors.
Journal of Natural Disasters | Year: 2012
The northwestern Pacific is one of the areas where the tropical cyclone (TC) occurs with the highest frequency and the maximum intensity. Extensive attention has been paid to the research of TC in this area. Based on the optimum track data for TC in northwestern Pacific provided by the Japan Metrology Agency ( JMA ) , the spatiotemporal variation characteristics of both the frequency and intensity of TC from 1951 to 2006 were comprehensively analyzed herein. First, the annual and monthly variations of TC during the 56 years were analyzed statistically, and by calculating the TC frequency in each 1° × 1 ° longitude-latitude grid, the spatial distribution was analyzed. Second , in accordance with the WMO standards of TC classification by wind speed, the annual and monthly variation of different intensities of TC during the 56 years was analyzed. Then, by calculating wind intensity indices, the influence extent of TC on each 1 ° × 1 ° longitude-latitude grid was acquired. The results show that, the regional distribution pattern of the frequency and intensity reflects the characteristics of the TC influence well, and provides a support for both the forecast and risk assessment of the typhoon disaster. Source
Hu Z.,Capital Normal University |
Hu Z.,Experimental Teaching Center for Geographic Science and Technology |
Hu Z.,Beijing Municipal Key Laboratory of Resources Environment |
Liu C.,Capital Normal University |
And 5 more authors.
Lecture Notes in Electrical Engineering | Year: 2012
Asia is an earthquake-prone continent in which earthquakes cause huge losses of lives and property. Efficient data management is and important basis for seismic risk assessment which can effectively improve the post-earthquake emergency response capacity to reduce disaster losses in Asia. Seismic risk assessment needs basic geographic data, remote sensing data, earthquake thematic data, seismic case data and documents data. In this paper Asia seismic risk assessment database construction content, database logical architecture, physical architecture are well designed, and base on the database design the Asia seismic assessment data management program are developed. In order to achieve the seismic risk assessment, the database needs many kinds of large volumes of data, and the data management needs to be efficient and convenient. In recent years, development of GIS technology, spatial database technology and computer technology provides an important foundation for the efficient management of seismic risk assessment data. This paper uses traditional relational database and spatial database engine (SDE) to complete the risk assessment database construction. A data management system is developed which achieves efficient data storage, management, display and processing. The database together with the data management system provides an important support for the Asian earthquake risk assessment. © 2012 Springer-Verlag. Source
Song W.-B.,Capital Normal University |
Song W.-B.,Beijing Municipal Key Laboratory of Resources Environment |
Xie X.-H.,Beijing Normal University |
Xu T.,Capital Normal University |
And 5 more authors.
Wetland Science | Year: 2014
The marsh wetlands in are featured by low-lying, changing river network and seasonal flooding in Honghe National Nature Reserve, China. There is a great challenge to simulate eco-hydrological processes using a hydrological model in the reserve. In this study, we investigated eco-hydrological processes in the marsh wetlands and proposed a new model calibration-validation framework for a hydrological model-Soil and Water Assessment Tool. In addition to the runoff from the outlet of a basin in the reserve, soil moisture from different sub-basins and various depths was measured. These runoff and soil moisture data were combined to calibrate and validate the model based on sensitivity analysis. During the calibration period, the determination coefficient (R2) for the runoff simulation was up to 0.7, and the relative error (RE) was about 21%. For the model validation, the simulation for soil moisture was also acceptable since R2 reached 0.7 and RE was less than 20%. The daily soil moisture reflects the status of internal humidity and the relationship between the soil type and the vegetation. Therefore, Soil and Water Assessment Tool model performed well during the calibration and the validation period and could be used to analyze the eco-hydrological processes in the reserve. Moreover, the soil moisture of four soil-vegetation types, meadow black soil-marshy meadow, meadow black soil-marsh, marsh soil-marshy meadow, and marsh soil-marsh, remained at high levels. So the eco-hydrological function of water regulation in the marsh wetlands was very significant. The four soil-vegetation types were within area of the seasonal water-logged or the perennial water-logged zones. The soil moisture gradient was the dominant factor, which controls the vegetation spatial patterns. It showed that the distribution of vegetation communities have accordingly shrunk into a banding distribution along a humidity gradient. So the marsh wetlands were in a well status and it was favorable for biodiversity conservation. The calibration-validation framework is potential to reduce the modeling uncertainties in such wetland area especially when the data is rather sparse. Source
Zhao W.,Beijing Municipal Key Laboratory of Resources Environment |
Tao S.,Beijing Municipal Key Laboratory of Resources Environment
2010 4th International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2010 | Year: 2010
Based on the monitoring summer data obtained from 87 air sampling stations in Beijing urban area from 2007 to 2009, the spatial distribution of PM0.3, PM3.0 and PM5.0 concentration and meteorological factors were simulated by using Kriging method. Meanwhile, the different regularity and spatial variability of inhalable particulate matter (IPM) were shown in the experiment. Furthermore, taking the case of data in 2009, the influences of different meteorological factors such as temperature, humidity and wind speed were analyzed and compared. Finally, based on land cover map abstracted from remote sensing image, research on the relationship of land use types and local IPM concentration has been carried out. The results showed that spherical models with nuggets could fit the variograms of airborne inhalable particulates. In recent years, the level of inhalable particulate pollution in Beijing has fallen substantially especially in 2008. The main polluted area was centralized at southwest, northwest was weaker. Pollution level in central city was relatively light, and the spatial relativity between three kinds of airborne inhalable particulate pollutant and their impact factors had spatial heterogeneity. As for the meteorological factors, the relative humidity significantly affected inhalable particulate pollution. Temperature was second, and the weakest factor was wind speed. © 2010 IEEE. Source