Abstract： Loess-paleosol sequences preserve records of climatic change during the Quaternary, which is important for paleoclimate study. In this study, a loess-palaeosol sequence from the Chumbur- Kosa （CK） site in...Abstract： Loess-paleosol sequences preserve records of climatic change during the Quaternary, which is important for paleoclimate study. In this study, a loess-palaeosol sequence from the Chumbur- Kosa （CK） site in the Sea of Azov region was investigated to reconstruct climatic variability during the Marine Isotope Stage （MIS）11- MIS 1, using proxies of grain size （GS）, magnetic susceptibility （xlf and Xfd（%））, carbonate content （CaCO3%） and soil color The results enabled formulation of a detailed description of the climatic characteristics related to each individual layer. The sequence indicates that the paleoclimate shifted progressively towards increasingly cooler, somewhat drier conditions. The CK section may thus be ideal for reconstructing climatie eondifions during the Middle and Late Pleistocene in the Sea of Azov region. However, the ）Of value of paleosol $2 in the CK profile indicates different characteristics from the other paleosol layers, dilution of carbonate resulting from carbonate leaching in L2 may be the main reason for the decrease in magnetic susceptibility. Furthermore, through simple analysis part of the environmental evolution process in the Sea of Azov region and Serbia during Middle and Late Pleistocene cycles. The climate cycle expressed by Xfd（%） and Xlf variations show similar patterns, with rapidly alternating cold and warm intervals. Nevertheless, although the two areas had different climatic regimes, geographical settings, and loess source areas, both exhibited similar climate change trends since the MIS 11.展开更多
Keriya River, one of the ancient Four Green Corridors in the Tarim Basin, recording the changes of climate-environment and the ancient Silk Road of the region. According to the archaeological data, historical material...Keriya River, one of the ancient Four Green Corridors in the Tarim Basin, recording the changes of climate-environment and the ancient Silk Road of the region. According to the archaeological data, historical materials and paleoclimates information, its eeo-environment and climate have taken great changes since the 1.09 Ma B.P, especially during the recent 2,000 years, many famous ancient cities having been abandoned and the south route of the Silk Road has been moved southward. This study illustrates the capability of the remote sensing data （radar data, topographic data and optical images） and historical materials, in mapping the ancient drainage networks. A major paleodrainage system of Keriya River has linked the Kunlun Mountains to the Tienshan Mountains, possibly as far back as the early Pleistocene. The Keriya River will have important implications for not only the understanding of the paleoenvironments and paleoclimates of Tarim Basin from the early Pleistocene to the Holocene, but also the changes of the Silk Road.展开更多
Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring ...Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. In SAR(Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using In SAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the In SAR scattering model for single-layer snow has been fully studied;however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA(Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an In SAR volumetric correlation of different types of multi-layer snow at the X band(9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also developed.The model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization In SAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization In SAR volumetric correlation and more conducive to the development of a parameter-inversion algorithm. The model can be applied to deepen our understanding of In SAR scattering mechanisms and to develop a snow parameter inversion algorithm.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41271024)International Cooperation and Exchanges Project(The record of landscape changes in Eurasian arid and semi-arid regions by loess-paleosol sequence of southern Russian on the million scales and its comparative study with Chinese loess(Grant No.No.41411130204)
文摘Abstract： Loess-paleosol sequences preserve records of climatic change during the Quaternary, which is important for paleoclimate study. In this study, a loess-palaeosol sequence from the Chumbur- Kosa （CK） site in the Sea of Azov region was investigated to reconstruct climatic variability during the Marine Isotope Stage （MIS）11- MIS 1, using proxies of grain size （GS）, magnetic susceptibility （xlf and Xfd（%））, carbonate content （CaCO3%） and soil color The results enabled formulation of a detailed description of the climatic characteristics related to each individual layer. The sequence indicates that the paleoclimate shifted progressively towards increasingly cooler, somewhat drier conditions. The CK section may thus be ideal for reconstructing climatie eondifions during the Middle and Late Pleistocene in the Sea of Azov region. However, the ）Of value of paleosol $2 in the CK profile indicates different characteristics from the other paleosol layers, dilution of carbonate resulting from carbonate leaching in L2 may be the main reason for the decrease in magnetic susceptibility. Furthermore, through simple analysis part of the environmental evolution process in the Sea of Azov region and Serbia during Middle and Late Pleistocene cycles. The climate cycle expressed by Xfd（%） and Xlf variations show similar patterns, with rapidly alternating cold and warm intervals. Nevertheless, although the two areas had different climatic regimes, geographical settings, and loess source areas, both exhibited similar climate change trends since the MIS 11.
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （Grant No. 41271427） and the National Key Technology R＆D Program （Grant No. 2012BAH27B05）.
文摘Keriya River, one of the ancient Four Green Corridors in the Tarim Basin, recording the changes of climate-environment and the ancient Silk Road of the region. According to the archaeological data, historical materials and paleoclimates information, its eeo-environment and climate have taken great changes since the 1.09 Ma B.P, especially during the recent 2,000 years, many famous ancient cities having been abandoned and the south route of the Silk Road has been moved southward. This study illustrates the capability of the remote sensing data （radar data, topographic data and optical images） and historical materials, in mapping the ancient drainage networks. A major paleodrainage system of Keriya River has linked the Kunlun Mountains to the Tienshan Mountains, possibly as far back as the early Pleistocene. The Keriya River will have important implications for not only the understanding of the paleoenvironments and paleoclimates of Tarim Basin from the early Pleistocene to the Holocene, but also the changes of the Silk Road.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41471065 & 41471066)the International Partnership Program of Chinese Academy of Sciences (Grant No. 131C11KYSB20160061)+1 种基金the Science & Technology Basic Resources Investigation Program of China (Grant No. 2017FY100502)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA19070201)
文摘Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. In SAR(Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using In SAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the In SAR scattering model for single-layer snow has been fully studied;however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA(Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an In SAR volumetric correlation of different types of multi-layer snow at the X band(9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also developed.The model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization In SAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization In SAR volumetric correlation and more conducive to the development of a parameter-inversion algorithm. The model can be applied to deepen our understanding of In SAR scattering mechanisms and to develop a snow parameter inversion algorithm.
