Conventional forward intersection measurement methods in close-range photogrammetry depend on on-site calibrations with aids of control points or parameters from other categories of visual sensors in an object coordinate system. This may restrict the wider adoption of machine vision system. To address these limitations, two key structural parameters were set for expressing the visual-related vectors and for building a measurement coordinate system located on carrier. Two categories of co-spherical resection algorithms were established to calibrate the two key structural parameters based on the resection of principal optic axes in their normal directions. A new parameter vector model was proposed for the collinear equation of co-spherical resection, in which three points on a principal optic axis were included, they are principal target point, perspective point, and tangent point. The vectors for the improved forward intersection measurement were expressed by structural parameters, optical parameters, and posture value of the camera in the measurement coordinate system. Experimental results demonstrated that the calibrations of the two structural parameters by the two co-spherical resection algorithms were both accurate, and the improved forward intersection strategy was effective. The strategy not only dispenses with on-site calibrations, but also achieves satisfactory measurement accuracy on both the spatial plane targets and the plant leaves. The parameter vector model, the two structural parameters, the two co-spherical resection algorithms, and the improved forward intersection strategy hope to be applied to machine-vision platforms with multi-degrees of freedom to facilitate control of robots.
The joint estimation of groundwater contaminant source characteristics and hydraulic conductivity is of great significance for reactive contaminant transport models in heterogeneous subsurface media. The accurate determination of the sorption parameters of such contaminants is also a key prerequisite for estimating the parameters of the groundwater system. In this study, to investigate the impact of the sorption parameter field on the accuracy of hydraulic conductivity and source characteristics estimation, numerical experiments were conducted in a synthetic aquifer considering the contaminant sorption process in groundwater models with varying sorption parameter settings. Iterative local updating ensemble smoother with geometric inflation selection (ILUES-GEO) was employed to assimilate hydraulic head and contaminant concentration data to jointly estimate the contaminant source information and hydraulic conductivity in a heterogeneous aquifer. The results indicated that the ILUES-GEO successfully recovers contaminant source information simultaneously with hydraulic conductivity, and its performance improves as more accurate sorption parameters are introduced. Furthermore, the influence of the ILUES algorithm parameters and ensemble size is investigated to improve the estimation accuracy. Additionally, the characterization of contaminant sources and hydraulic conductivity fields is influenced by the number and locations of measurements. This study can help to understand the significance of sorption parameter setting for the joint estimation of reactive contaminant source and hydraulic parameters.
Abstract The Forchheimer and Izbash equations have been long employed to investigate the behavior of non‐Darcian flow toward a well in various aquifer systems, but both two equations inevitably introduce problems such as more or less empirical nature, and dimensional unbalance. Therefore, this work makes the attempt to introduce the fractional Darcian model for characterizing the non‐Darcian behavior flow toward a fully penetrating well in a confined aquifer instead of the Forchheimer and Izbash equations. In this study, a fractional Darcian model‐based analytical solution in the time domain is obtained by means of Laplace transform and linearization approximation. The proposed analytical solution of this study can be readily reduced to the classical Theis solution for Darcian flow. Meanwhile, the late‐times and steady‐state analytical solutions for non‐Darcian flow described using the fractional Darcian model are also developed. Moreover, a comparison with previous analytical solutions shows that the newly derived analytical solution in this study is sufficiently accurate at later times. The influences of different parameters on transient drawdown are investigated. The results indicate that the fractional derivative order and hydraulic conductivity have a large influence on drawdown compared with other parameters. The introduction of fractional Darcian model in this study could also provide potential application for further investigations of non‐Darian flow behavior toward fully or partially penetrating wells in different aquifer systems, which can be very beneficial for hydrology and other related fields.
Abstract. Human-perceived thermal comfort (known as human-perceived temperature) measures the combined effects of multiple meteorological factors (e.g., temperature, humidity, and wind speed) and can be aggravated under the influences of global warming and local human activities. With the most rapid urbanization and the largest population, China is being severely threatened by aggravating human thermal stress. However, the variations of thermal stress in China at a fine scale have not been fully understood. This gap is mainly due to the lack of a high-resolution gridded dataset of human thermal indices. Here, we generated the first high spatial resolution (1 km) dataset of monthly human thermal index collection (HiTIC-Monthly) over China during 2003–2020. In this collection, 12 commonly used thermal indices were generated by the Light Gradient Boosting Machine (LightGBM) learning algorithm from multi-source data, including land surface temperature, topography, land cover, population density, and impervious surface fraction. Their accuracies were comprehensively assessed based on the observations at 2419 weather stations across the mainland of China. The results show that our dataset has desirable accuracies, with the mean R2, root mean square error, and mean absolute error of 0.996, 0.693 ∘C, and 0.512 ∘C, respectively, by averaging the 12 indices. Moreover, the data exhibit high agreements with the observations across spatial and temporal dimensions, demonstrating the broad applicability of our dataset. A comparison with two existing datasets also suggests that our high-resolution dataset can describe a more explicit spatial distribution of the thermal information, showing great potentials in fine-scale (e.g., intra-urban) studies. Further investigation reveals that nearly all thermal indices exhibit increasing trends in most parts of China during 2003–2020. The increase is especially significant in North China, Southwest China, the Tibetan Plateau, and parts of Northwest China, during spring and summer. The HiTIC-Monthly dataset is publicly available from Zenodo at https://doi.org/10.5281/zenodo.6895533 (Zhang et al., 2022a).
The stratum of Paleogene System at Shahejie formation 3rd Middle sub-member in Jizhong depression is universal distribution. On the base of the welldrilling, core and quake data etc. as characterization and quantification, the lithofacies paleogeography maps of Paleogene System at Shahejie formation 3rd Middle sub-member in Jizhong depression are compiled with the single factor analysis and multifactor comprehensive mapping method proposed by Feng Zengzhao Prof‥ The stratum of Paleogene System at Shahejie formation 3rd Middle sub-member mainly develops some sedimentary facies including alluvial fan, stream, (fan) braided river delta, sublacustrine fan in shore and lake. The result of research shows that the sequence stratum mainly develop umbrella alluvial fan-stream-(fan)braided river delta-lake sedimentary system. Jizhong depression of Paleogen System had gone through the two phases of sedimentary evolvement for the deposit (SQ3) of fault expansive up to the chin age for basin in earlier Eocene Series.
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