National Disaster Reduction Center

Beijing, China

National Disaster Reduction Center

Beijing, China
Time filter
Source Type

Zheng W.,Central South University | Hu J.,Central South University | Zhang W.,National Disaster Reduction Center | Yang C.,Central South University | And 2 more authors.
Science China Information Sciences | Year: 2017

The ability of differential interferometric synthetic aperture radar (DInSAR) technology used for centimeter level deformation detection has been well-proved. Nevertheless, the applications of DInSAR under the low Earth orbit (LEO) are limited to the line-of-sight (LOS) measurements, the limited observation area and the long revisited time. Geosynchronous SAR (GEO SAR), which runs in the height of 36000 km with the advantage of a short revisit time and a large observation area, is a potential approach to overcome the series problems in LEO SAR. This paper focuses on estimating three-dimensional (3D) displacements by using GEO SAR DInSAR measurements acquired from multiple imaging geometries. Aiming to provide a normal solution for geologic hazard monitoring and relative geophysical application in the future, the errors induced by decorrelation noise, orbital ramp and ionospheric distortion are analyzed for the GEO SAR DInSAR measurements. A series of experiments have been conducted to find the relationship between the 3D displacements and the DInSAR observations which are provided with different noises and combinations of imaging geometries. The results reveal that 3D displacements can be expected from the combination of left- and right-looking GEO SAR DInSAR measurements. In particular, the north-south solution can achieve centimeter and even millimeter level. © 2017, Science China Press and Springer-Verlag Berlin Heidelberg.

Zhou H.,National Disaster Reduction Center | Zhang C.,National Disaster Reduction Center
Journal of Natural Disasters | Year: 2017

Disaster relief is an important part of integrated disaster risk governance system, and different from the conventional disaster relief, large-scale disaster relief will be mere influenced by the various disaster types. Taking the Wenchuan earthquake and drought in SW China in 2009-2010 as examples, analysis discovered that the both types of large-scale disaster relief show obvious differences from conventional one in three aspects, (1) on the emergency relief supplies, the sudden disaster has an obvious instantaneous demand peak after the disaster occurred, especially in the 10 days after disaster; while for the slow-onset disaster, it is not typical on this characteristic. (2) On the diversity of disaster relief objects, sudden large-scale disasters result in largest number of relief objects and highest diverse need, in which sudden disaster has more diverse objects due to its characteristics of wide range, stronger identity and so on. (3) On the post-disaster relief, large-scale disasters need an overall arrangement of post disaster relief, in which sudden disaster will be more integrated on relief policies and measures than slow-onset disaster. (4) Flexibility, vulnerability, resilience and other related theory can better explain the above three differences. The results of this study can provide a theoretical basis for enriching disaster relief theory, and improving the large-scale disaster relief system.

Wen Q.,National Disaster Reduction Center | Chen S.,National Disaster Reduction Center | He H.,National Disaster Reduction Center | Li S.,Beijing Municipal Research Institute of Environmental Protection | And 2 more authors.
Journal of Natural Disasters | Year: 2012

Unmanned aerial vehicle (UAV) system has the advantage of flexible, rapid response. It is suitable for natural disaster monitoring and assessment. This paper introduced the composition of UAV remote sensing system, the emergency process and data process flow in Yingjiang, Yunnan earthquake disaster. Then, the UAV remote sensing image and pre-disaster high resolution satellite image were compared, housing damage, disaster relief tents, roads damage and traffic jam were monitored and assessed. It turned out that results are good. However, the data processing efficiency and the acquisition capability of three dimension information for UAV remote sensing system need to be further improved.

Wang Z.,National Disaster Reduction Center | Wang Z.,Key Laboratory of Integrated Disaster Assessment and Risk Governance | He F.,PICC Property and Casualty Company Ltd | Fang W.,The Academy of Management | And 2 more authors.
Natural Hazards | Year: 2013

Food security has drawn great attention from both researchers and practitioners in recent years. Global warming and its resultant extreme drought events have become a great challenge to crop production and food price stability. This study aimed to establish a preliminary theoretical methodology and an operational approach for assessing the physical vulnerability of two wheat varieties ("Yongliang #4" and "Wenmai #6") to agricultural drought using Environmental Policy Integrated Climate model (EPIC). Drought hazard index was set up based on output variables of the EPIC water stress (WS), including the magnitude and duration of WS during the crop-growing period. The physical vulnerability curves of two wheat varieties to drought were calculated by the simulated drought hazard indexes and loss ratios. And the curve's effect on drought disaster risk was defined as A, B and C sections, respectively. Our analysis results showed that (a) physical vulnerability curves varied between two wheat varieties, which were determined by genetic parameters of crops; (b) compared with spring wheat "Yongliang 4#" winter wheat "Wenmai 6#" was less vulnerable to drought under the same drought hazard intensity scenario; (c) the wheat physical vulnerability curve to drought hazard displayed a S shape, suggesting a drought intensity-dependent magnifying or reducing effect of the physical vulnerability on drought disasters; (d) the reducing effect was mainly in the low-value area of vulnerability curve, whereas the magnifying effect was in the middle-value area, and the farming-pastoral zone and the Qinling Mountain-Huaihe River zone formed important spatial division belts. © 2013 Springer Science+Business Media Dordrecht.

He R.,CAS Technical Institute of Physics and Chemistry | He R.,University of Chinese Academy of Sciences | Lin Z.S.,CAS Technical Institute of Physics and Chemistry | Zheng T.,Nanjing University of Technology | And 2 more authors.
Journal of Physics Condensed Matter | Year: 2012

The development of ultraviolet (UV) nonlinear optical (NLO) crystals demands optical materials with wide energy band gaps. Here we report first-principles studies on the electronic structures in several UV NLO borates with representative structures. Combined with model analysis, we find that the oxygen non-bonding 2p orbitals play an important role on the top of valence bands. The energy band gap can be adjusted by modifying the coordination environment around the oxygen atoms. Under ideal conditions the energy band gaps achieve 9eV if the non-bonding orbitals are totally eliminated, despite the original values varying from 6.6 to 8.3eV. © 2012 IOP Publishing Ltd.

Lin Z.S.,CAS Technical Institute of Physics and Chemistry | Kang L.,CAS Technical Institute of Physics and Chemistry | Kang L.,University of Chinese Academy of Sciences | Zheng T.,Nanjing University of Technology | And 4 more authors.
Computational Materials Science | Year: 2012

The predictive capabilities of the density functional theory with various exchange-correlation functionals on the energy band gaps and optical properties in ultraviolet nonlinear optical (UV NLO) crystals are systematically investigated. We find that the energy band gaps of these crystals can be accurately predicted by the non-local hybrid functionals and sX-LDA functionals, but their calculated optical properties are not consistent with the experimental results compared to the usually adopted LDA or GGA functionals with the scissors corrections. Accordingly, we propose that a precise and effective strategy to study the optical properties in the UV NLO crystals without any experimental parameter should be the combination of different functional calculations. © 2012 Elsevier B.V. All rights reserved.

Yang Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yang Y.,University of Chinese Academy of Sciences | Su H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Su H.,Texas A&M University-Kingsville | And 3 more authors.
Journal of Applied Remote Sensing | Year: 2012

Accurate estimation of evapotranspiration (ET) has long been an important issue in hydrology. Many experimental observations indicate advection has a great impact on ET in arid and semiarid areas. However, most of the remote sensing models only focus on the vertical energy balance and deviate from reality. A revised Penman equation has been derived to estimate actual ET under normal conditions in order to account for advection. The parameter of the water availability for ET is introduced and the Ts/f (surface temperature and vegetation fraction) space is used to characterize this parameter in the revised formula. The estimates were validated using the observations measured with eddy covariance systems at the Yingke station. In 22 of all 24 days, the difference between the observations and the estimates was smaller than 70 W?m2. The correlation coefficient is 0.91 and the RMSE is 48.38 W/m2. This finding reveals that this approach is capable of providing reliable results. In addition, when considering advection, the potential ET can be 83.23 W/m 2 larger than the available energy. This finding indicates that the advection effect needs to be considered in remote sensing models in order to derive more reliable regional ET. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Huang H.,CAS Technical Institute of Physics and Chemistry | Huang H.,National Disaster Reduction Center | Lin Z.S.,CAS Technical Institute of Physics and Chemistry | Bai L.,CAS Technical Institute of Physics and Chemistry | And 4 more authors.
Solid State Communications | Year: 2010

The electronic properties of SrAlF5 and BaMgF4 have been studied using the ab initio plane-wave pseudopotential method. Based on the electronic band structures, the linear and nonlinear optical properties for these crystals are theoretically determined. Both the calculated refractive indices and nonlinear optical effects are in reasonable agreement with the available experimental values. The origin of the nonlinear optical effects is elucidated through a real-space atom-cutting analysis. It is found that in SrAlF5 crystals the contribution of the (AlF6) 3- anionic group to both the anisotropy of the linear optical and second harmonic generation effect is dominant while that of the A-site cations Sr2+ can be negligible. With the size increase of the A-site cations the contribution of Ba2+ for the optical effects in BaMgF4 become more pronounced and is comparable to that of the (MgF6) 4- anionic group. © 2010 Elsevier Ltd. All rights reserved.

Nie C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Nie C.,University of Chinese Academy of Sciences | Li H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yang L.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 5 more authors.
Quaternary International | Year: 2012

This study focuses on extreme temperature and extreme precipitation changes in Guangxi Province of south China, which has experienced increased numbers of climate disasters in recent years. In this paper, spatial and temporal changes in extreme temperature and extreme precipitation were reconstructed for the period 1960-2009. The method of FFT filtering was used to smooth time series of extreme temperature and extreme precipitation, linear regression to calculate linear fits, and spline interpolation to interpolate station data and estimate linear changes. The results show that the annual extreme temperature increased in most of the area during 1960-2009, especially in the northeast. The greatest increase was the extreme temperature in winter, compared to that in autumn, summer and spring in order from high to low across most of the study area. The annual extreme precipitation changed little in the first three decades and increased significantly in the last two decades, and varied with region and season. Spatially, the annual trend of extreme precipitation increased across most of the province, except in some areas of the southeast. The seasonal change trend of extreme precipitation varied greatly across different areas. © 2012 Elsevier Ltd and INQUA.

Yang Y.-Q.,Institute of Disaster Prevention | Hu J.-F.,National Disaster Reduction Center | Xi M.-H.,Institute of Disaster Prevention
Journal of Natural Disasters | Year: 2011

A large-scale debrisflow disaster occurred in Zhouqu County, Gansu Province on August 8, 2010, which made huge economic losses and people's death. Based on grey correlation method, the main influencing factors could be found by the analysis of influence of debris flow hazard in Zhouqu. The results show that, the heavy rainfall is direct dynamic force to cause the debris flow disaster and human's activities are the indirect reasons to lead to the geological disaster. The development of agriculture and animal husbandry has the biggest influence on debris flow in all human's factors. Author considers that the reasonable development of agriculture and animal husbandry should be planned appropriately. In addition, afforestation or converting cropland to forest should be strengthened, ecological environment impact assessment must be carried out for the new-building hydropower station to reduce natural disasters risk.

Loading National Disaster Reduction Center collaborators
Loading National Disaster Reduction Center collaborators