Geothermal resources have become an increasingly important source of renewable energy for electrical power generation worldwide. Combined Three Dimension (3D) Subsurface Temperature (SST) and Land Surface Temperature (LST) measurements are essential for accurate assessment of geothermal resources. In this study, subsurface and surface temperature distributions were combined using a dataset comprised of well logs and Thermal Infrared Remote sensing (TIR) images from Hokkaido island, northern Japan. Using 28,476 temperature data points from 433 boreholes sites and a method of Kriging with External Drift or trend (KED), SST distribution model from depths of 100 to 1500 m was produced. Regional LST was estimated from 13 scenes of Landsat 8 images. Resultant SST ranged from around 50• C to 300• C at a depth of 1500 m. Most of western and part of the eastern Hokkaido are characterized by high temperature gradients, while low temperatures were found in the central region. Higher temperatures in shallower crust imply the western region and part of the eastern region have high geothermal potential. Moreover, several LST zones considered to have high geothermal potential were identified upon clarification of the underground heat distribution according to 3D SST. LST in these zones showed the anomalies, 3 to 9• C higher than the surrounding areas. These results demonstrate that our Remote Sens. 2015, 7 2648 combination of TIR and 3D temperature modeling using well logging and geostatistics is an efficient and promising approach to geothermal resource exploration.

Some factors (i.e. lithology, topography, climate, the change of population as well as land use during the past 50 years) that could have great influence on the development of gully in the arid-hot basin of Jinshajiang valley were investigated. The results show that the factors leading to the strong gully erosion in this area include: the widely distributed Yuanmou group stratum, which promotes the development of gully erosion; the unique geomorphologic configuration that is prone to rock fall and gully erosion; the strong and time-concentrated rainfall; the arid-humid alternate climate characteristics that prepares the ground for the development of fissures in soils; the arid-hot climate that goes against the growth and recovery of vegetation; and the unreasonable and abusive human activities.

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The crash of an aircraft with an almost vertical attitude in Wuzhou, Guangxi, China, on March 21, 2022, has caused a robust discussion in the civil aviation community. We propose an active disturbance rejection controller (ADRC) for suppressing aeroelastic vibrations of a flexible aircraft at the simulation level. The ADRC has a relatively simple structure and it has been proved in several fields to provide better control than the classical proportional-integral-derivative (PID) control theory and is easier to translate from theory to practice compared with other modern control theories. In this paper, the vibration model of the flexible aircraft was built, based on the first elastic vibration mode of the aircraft. In addition, the principle of ADRC is explained in detail, a second-order ADRC was designed to control the vibration model, and the system’s closed-loop frequency domain characteristics, tracking effect and sensitivity were comprehensively analyzed. The estimation error of the extended state observer (ESO) and the anti-disturbance effect were analyzed, while the robustness of the closed-loop system was verified using the Monte Carlo method, which was used for the first time in this field. Simulation results showed that the ADRC suppressed aircraft elastic vibration better than PID controllers and that the closed-loop system was robust in the face of dynamic parameters.

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Abstract:The quantification of spatial heterogeneity can be used to examine the structure of ecological systems. The 2008 Wenchuan earthquake caused severe vegetation damage. In addition to simply detecting change, the magnitude of changes must also be examined. Remote sensing and geographic information system techniques were used to produce landscape maps before and after the earthquake and analyze the spatial-temporal change of the vegetation pattern. Landscape metrics were selected to quantify the spatial heterogeneity in a categorical map at both the class and landscape levels. The results reveal that the Wenchuan earthquake greatly increased the heterogeneity in the study area. In particular, forests experienced the most fragmentation among all of the landscape types. In addition, spatial heterogeneity in a numerical map was studied by using variogram analysis of normalized difference vegetation indices derived from Landsat images. In comparison to before the earthquake, the spatial variability after the earthquake had doubled. The structure of the spatial heterogeneity represented by the range of normalized difference vegetation index (NDVI) variograms also changed due to the earthquake. Moreover, the results of the NDVI variogram analysis of three contrasting landscapes, which were farmland, broadleaved forest, and coniferous forest, confirm that the earthquake produced spatial variability and changed the structure of the landscapes. Regardless of before or after the earthquake, farmland sites are the most heterogeneous among the three landscapes studied.

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