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The Autonomous Underwater Vehicle (AUV) is a submersible with energy, autonomous navigation, and a wide range of sensors, which is an important means of marine observation. More and more attention has been paid to the long-term observation of the marine environment using AUVs. Due to the restriction of energy and operation mode, traditional autonomous underwater vehicle can work very short time. In order to meet the long-term observation requirements of marine environment, a new type of autonomous underwater vehicle named Long Term Station-keeping Profile Observing AUV with variable buoyancy system has been developed. By carrying the variable buoyancy system, the AUV can be adjusted to neutral before travelling which will help to reduce the resistance; When vertical profile observing, the AUV’s diving and surfacing are realized by VBS without continuous power consumption; During the observation interval, AUV is adjusted to neutral in water, and by closing the carrying equipment, the AUV gets into sleep state so as to save energy. Through these measures, it is expected to achieve long-term observation by AUV for one month. The key is the high precision variable buoyancy system with bidirectional regulation ability, which can adjust the residual buoyancy and pitch angle at any working depth. In order to realize the precise adjustment of buoyancy, a seawater piston cylinder is adopted. By measuring the position of the piston in the sea water cylinder accurately, the precise control of the amount of buoyancy adjustment can be realized. Through laboratory proofing and sea tests, the variable buoyancy system has attained its design targets expected. The AUV equipped with this system can realize underwater suspension at fixed depth, diving, surfacing and low energy sleep, which has carried out many marine applications in the Yellow Sea, the South China Sea and the East China Sea, and it proved to be stable and reliable. The results of laboratory and sea tests show that the variable buoyancy system with seawater cylinder features high accuracy and reliable operation.

The diving plane motion of autonomous underwater vehicles (AUVs) is a complex multivariable nonlinear system with pitch-heave coupling. Tornambe’s controllers (TCs) can online estimate the dynamic uncertainty regardless of the type of disturbance. The TCs for depth and pitch angle are adopted to achieve multivariable decoupling control by introducing virtual control inputs. The methodology can obtain fast and non-overshoot control of depth and pitch angle in the diving and floating process. Simulation results demonstrated the effectiveness of the proposed control scheme.

In this paper, two digital elevation models of debris flow in Yingxiu mountain area are generated; one is from contour lines with manual interpretation before earthquake and the other is from high resolution aerial photos using MapMatrix software. By analyzing three random points which are not in the same edge, a new formula for calculating the volume from these three points to their projection on the datum plane is derived. Then, the volumes of the two DEMs before and after earthquake can be calculated, and the volume of the total debris flow is the difference of those two.

Land surface temperature (LST) of the Nanchong City in China was retrieved using Landsat TM/ETM+ images, which obtained on September 15, 1988, July 22, 2000, and September 20, 2007 respectively, and then be classified by Mean-standard Deviation method. The spatio-temporal evolution of UHI was analyzed including UHI distribution variation and transformation. Research result are the following: (1) The UHI area in the Nanchong city was continually increasing from 1988 to 2007, and the rate in the later period (from 2000 to 2007) was 1.8 times that in the previous period (from 1988 to 2000). The UHI expansion was synchronous with built-up area, and the expansion form was extending along and outwards the Jialing River. (2) The UHI-in area was far greater than the UHI-out area from 1988 to 2007. In the previous period, the UHI-into rate was 4.0 times that of UHI-out, and in the later period, the UHI-into rate was 2.2 times the UHI-out rate. Comparison of the previous and later period, the UHI-into rate or UHI-out rate was increasing, but the increased scope of UHI-into rate was more 22.42 hm2/a than UHI-out rate. In short, the UHI in the Nanchong City was continuously strengthening from 1988 to 2007, and the rate in the latter period was higher than that in the previous period.

Taking Mianyang city as the study area and TM /ETM+ images of 1988, 2000 and 2007 as the data source. At first, image geometric correction must be done, and urban built-up area would be extracted by the methods of NDBI and supervised classification, then the brightness temperature map was generated by the radiometric calibration and retrieving brightness temperature. At last, the author analyzes the tendency of urban expansion and urban heat island effects. The results show that: (1) The urban built-up area of Mianyang city has been expanding rapidly during the past twenty years, which expanded mainly in the northeast from 1988 to 2000, and urban area increased from 18.3 km2 to 52.6 km2, the increased area is about 34.3 km2; from 2000 to 2007 the outstretched direction is northwest and urban area increased from the 52.6 km2 to 88.1 km2, the increased area is about 35.5 km2, the direction of expansion is limited by the Fujiang river and Anchang river, (2) The city's expansion resulted in the surface temperature gradually raise, and heat island area also increased from 12.7 km2 in 2000 to 26.0km2 in 2007, the increased area of the urban heat island was about 13.3 km2 during 7 years, the proportion index of urban heat island increased 5%. And the summer's heat island intensity was significantly higher than winter, urban expansion and distribution of heat island showed consistency in space.

Rainfall is an important factor which causes soil erosion. Spatial interpolation is an effective way to extrapolate the unknown data according to rainfall data discrete observing point. This article selected data which were obtained from seven observing points near the Ertan Hydropower Station on the Yalong River in 1988.Fiver interpolation methods were used in this research, which were inverse distance weight tension (IDW), spline , kriging, field interpolation and trend surface analysis respectively. Cross-validation results showed that the spline method is the best interpolation method for rainfall data in this research area.

Base on synthetically analysis of Mountains terrain characteristics, this paper uses analytic hierarchy process (AHP) to study classification of Mountains terrain characteristics of the Sichuan Mountains which lies in China's Sichuan Province, according to applying characteristics of AHP. This paper builds the recursion stage structure model using to the mode of highestlevel, middle-level and lowest-level. In the light of the five extracted classification factor and combining the assessed index of Mountains terrain characteristics, an index system should divide into A which notes target-layer and B which notes index-layer (factor-layer). According to the index system, the weights of five extracted classification factors are calculated by using established judgment matrixes. Sichuan Mountains terrain Layer can be extracted in ArcGIS and the result of characteristic is analyzed. Finally, The result of seven characteristics of classification is obtained, which supplies the new classification evaluate means for mountainous region synthesized research and application.