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Dune system waveform evolution simulation on the terylene substances using Olson's dynamical analogies, similarity criteria and dimensional analysis
No full textIt is well known that sand waves are formed by the action of either wind or water (through the waves or tidal currents). Modeling of the evolution of tidal sand waves is the basis of marine and river dune dynamics. Both the river dunes and tidal sand waves are generated by the same physical mechanisms. Hence, it is possible to simulate such phenomena using uniform or similar equations, which can be explicated not only for the linear scales, but also for nonlinear systems and non-stationary boundary conditions. Morphodynamic modeling of tidal sand waves is usually performed using computer software algorithms, but the aim of our work is realization of direct physical modeling of tidal sand waves based on chemically different media using several hydrodynamical / hydraulical similarity criteria and principles of the unified interpretation of the wave phenomena in the framework of nonlinear physics. We also use the scaling principles for microscopic simulation of the effects observed on the mesoscopic and "macroscopic" levels (sensu lato), for direct observation of them at the microscopic level using complex electron microscopy instrumentation
Benthic foraminiferal, Mg/Ca-based, paleotemperatures spanning the Cenozoic from ODP Site 121-757
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Field measurements and high resolution reference data of leaf area index, fraction of vegetation cover and clumping index in Honghe, China, 2019
No full textThe file includes both field measured and satellite derived high resolution leaf area index(LAI), fraction of vegetation cover(FVC) and clumpling index(CI) data obtained over the Honghe farm in northeastern China. The Honghe farm (centered at 47°39′N, 133°31′E) is located in the east of the Heilongjiang province, northeast China. Five plots in 400 m × 600 m were selected in the Honghe farm in 2019. Within each plot, about 50 - 60 elementary sampling units (ESUs) about 20 m ×20 m in size were selected in different weeks with a moving sampling strategy to avoid the sampling disturbance. Field LAI/FVC/CI measurements were performed weekly June 22 to August 26, 2019. All ESU measurements made with Digital hemispherical photography (DHP) within a plot were averaged to represent the plot LAI/FVC/CI. High-resolution reference data was generated with cloud-free harmonized Landsat, and Sentinel-2 (HLS) imagery based on random forest models for 2019, respectively. The HLS V1.4 dataset with a spatial resolution of 30 m (L30 and S30) was used for upscaling (https: //hls.gsfc.nasa.gov). In the random forest model, the reflectances of the blue, green, red, and near-infrared bands were used as explanatory variables, whereas LAIe, LAI, and FVC were used as the explained variables. The model was trained with yearly ground measurements and assessed by 10-fold cross-validation, for which nine-tenths of the samples were used for training and the remainder of the samples were used to evaluate the model. This step was run 10 times until all samples were looped. The optimal hyperparameters of the model (e.g. the number of trees and the maximum depth of the tree) were determined by selecting parameters corresponding to the best performance after iterative running
Depth integration of ODP Hole 177-1090D
No full textAlkenones, lipid biomarkers produced by certain species of coccolithophores and preserved in marine sediment cores, are a well-established proxy of sea surface temperature (SST). Here, we share a dataset containing a high resolution (~2-3 kyr) record of previously unpublished SST estimates for ODP Site 1090 during the Pliocene, calculated using the Uk'37 alkenone unsaturation index. The data spans approximately 4.27-2.58 Ma. We additionally supply the estimated maximum %C37:4, revealing low concentrations of this ketone. Using our SST estimates and shipboard data (magnetic susceptibility and cryomagnetic inclination), we produced an improved composite of ODP Site 1090 Holes D and E by correlating the two holes' properties. We then used biostratigraphic, magnetostratigraphic, and SST data to establish constraints for our age model. Although alkenone-based SST records Site ODP 1090 records already exist, we were motivated to create this reconstruction because inconsistent temperature estimates across existing reconstructions (Etourneau et al., 2010 & Martínez-Garcia et al., 2010) and unusually high reported C37:4 values in the Martínez-Garcia record. Our record reveals both lower SST estimates and lower %C37:4 than those in the Martínez-Garcia record