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Home > Papers > Natural-Geography-(including-Chemical-Geography,-Ecological-Geography,-Geomorphology,-ice
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1. Evaluation of ERA5 temperature and precipitation data in Fujian Province of China. | |||
Amandu Dennis Tagawa,Gao Lu | |||
Earth Science 11 March 2022 | |||
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Abstract:InAlthough reanalysis data has been widely applied over the world in the past two decades, the latest generation reanalysis, ERA5 produced by ECMWF, has not been evaluated on local scales. In this study, monthly air temperature and monthly total precipitation data from 22 meteorological stations in Fujian Province was applied to validate the reliability of ERA5 in 1979-2019. The results showed that ERA5 generally performed well in capturing temporal pattern of temperature and precipitation in Fujian Province of China. The correlation coefficient between observations and ERA5 for temperature ranged from 0.996 to 0.999. The RMSE ranged between 0.36 C and 5.49 C with an average of 1.08 C over all stations. ERA5 monthly minimum temperature, maximum temperature and mean temperatures showed the significant correlations with r2 ranged from 0.87 to 0.89. The correlation coefficient ranged from 0.6 to 0.81 with an average of 0.7 for all the stations which indicates that ERA5 captured well for annual monthly precipitation. The largest RMSE was 625.59mm found at Pucheng station. The biases ranged from -138.8mm to 529.4mm with average bias value of 148.2mm for annual precipitation. The bias difference was possible from the height differences between ERA5 grid point and height of the observation. | |||
TO cite this article:Amandu Dennis Tagawa,Gao Lu. Evaluation of ERA5 temperature and precipitation data in Fujian Province of China.[OL].[11 March 2022] http://en.paper.edu.cn/en_releasepaper/content/4756636 |
2. Analysis on the current situation of land use and economic development in Yantai city | |||
LIU Luyu,WANG Qiuxian,WU Xiao | |||
Earth Science 02 September 2019 | |||
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Abstract:In this paper, based on the remote sensing image of Landsat7 TM/ETM, the ArcGIS10.3 software is used to interpret the land use in Yantai 2015, and the Land Use Remote sensing classification of China\'s coastal zone is classified as the basis, then the land use status of Yaitai 2015 is obtained. The paper analyzes the matching relationship between land use status and economic development by combining the state of economic development, relevant literature and related Yearbook. The following conclusions are drawn: ①The main land utilization type of Yantai 2015 are arable land, woodland, garden and construction sites, while the unused land area is very small. ②The protection of coastal wetlands in Yantai has been better in recent ten years, and the methods of inshore aquaculture and other utilization have increased. ③ The development and policy of Yantai economy is the main driving force of the change of land use mode. ④ The Yantai city belongs to the retarded type of land use benefit, and the development degree of barely coordinating can′t provide a big impetus for economic development. | |||
TO cite this article:LIU Luyu,WANG Qiuxian,WU Xiao. Analysis on the current situation of land use and economic development in Yantai city[OL].[ 2 September 2019] http://en.paper.edu.cn/en_releasepaper/content/4749542 |
3. Analysis on Land Use Dynamic Changes in Qingdao from 2005 to 2015 based on ArcGIS | |||
Zhuotao Liu,Qiuxian Wang,Xiao Wu | |||
Earth Science 30 August 2019 | |||
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Abstract:In order to study the land use change situation of Qingdao in recent 10 years, this paper used the land Use classification system of China\'s coastal zone to overlay the land use of 2015 by visual interpretation with 2005 data in Arcgis10.2. The results showed that the residence of Qingdao increased 1612.3km2, the area of urban mining increased 351.2km2, the area of woodland increased 499.7km2, and the area of arable land decreased 1911.9km2, the grassland areas decreased 342.4km2, and the water body decreased 277.4km2. These changes were mainly due to the speed of urbanization, another reason was that the Government attached importance to environmental issues, vigorously carried out afforestation and returned farmland to forest. The research provided scientific basis for local government departments to formulate targeted land use planning and policies, which is of great practical significance for regional comprehensive, coordinated and sustainable development. | |||
TO cite this article:Zhuotao Liu,Qiuxian Wang,Xiao Wu. Analysis on Land Use Dynamic Changes in Qingdao from 2005 to 2015 based on ArcGIS[OL].[30 August 2019] http://en.paper.edu.cn/en_releasepaper/content/4749450 |
4. Insolation-driven monsoon-mediated changes in Earth's surface processes in mid-latitude East Asia since the last deglaciation | |||
LIU Jianbao,CHEN Qiaomei,XIE Chengling | |||
Earth Science 05 May 2016 | |||
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Abstract:The stability of Earth's critical zone is intimately linked with erosion, chemical weathering and the vegetation type and density, therefore affecting the global biogeochemical processes and in turn the global climate. However, there is a lack of knowledge on how Earth's critical zone processes have changed over time. Here we rebuild erosion-weathering-vegetation interactions since ~14.7 ka using geochemical records of a radiocarbon-dated sediment core from Gonghai Lake in North China. Our results revealed distinct, millennial, late deglacial-Holocene erosion and weathering patterns and transitions. Chemical Index of Alteration (CIA) molar, a humidity proxy, indicated low humidity during the late deglacial ~11.5-14.7 ka, high humidity during the early-mid Holocene ~11.5-3.2 ka, and intermediate humidity during the late Holocene interval since ~3.2 ka. Comparison of our records with other climate reconstructions further suggested an orbital-phased humidity changes in North China. This study provides evidence for the solar-forcing controlled Earth's surface processes in the mid-latitude China under natural climate conditions. | |||
TO cite this article:LIU Jianbao,CHEN Qiaomei,XIE Chengling. Insolation-driven monsoon-mediated changes in Earth's surface processes in mid-latitude East Asia since the last deglaciation[OL].[ 5 May 2016] http://en.paper.edu.cn/en_releasepaper/content/4686394 |
5. Effect of Forest Gaps on the Photosynthetic Physiology of Castanopsis kawakamii seedlings | |||
TANG Rong,HE Zhongsheng,LIU Jinfu,SU Songjin,ZHENG Shiqun,HONG Wei | |||
Earth Science 10 April 2015 | |||
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Abstract:The variations of photosynthetic physiology in plants were the dominant factors that could affected seedlings' dynamic growth. The objective of this study was to explore the effects of weak light on photosynthetic physiology of C.kawakamii seedlings by the measurements of chlorophyll contents, net photosynthetic rate (Pn), and chlorophyll fluorescence in forest gaps and non-gaps. The results showed that: (1) the contents of chlorophyll a (Chl-a), chlorophyll b (Chl-b), and total chlorophyll (total Chl) of C.kawakamii seedlings in forest gaps were lower than those of non-gaps while the value of chlorophyll a/b (Chl-a/b) in forest gaps was higher than that of non-gaps. The increase of Chl-b content improved the absorption of light energy which could conducive to enhance the adaptability of seedlings in non-gaps under the weak light condition, (2) the Pn of C.kawakamii seedlings in forest gaps was higher than those of non-gaps, which showed that the formation of forest gaps could improve seedlings' photosynthetic capacity and promote their growth, and (3) under the weak light condition, the initial fluorescence (Fo) of C. kawakamii seedlings in the low age classes of forest gaps and the high age classes in non-gaps showed an increasing trend. Weak light restrained the seedlings' photochemical efficiency with a downward trend in PSII photochemical conversion efficiency (Fv/Fm) for the low age classes of forest gaps. Photochemical quenching (qP) of C.kawakamii seedlings in forest gaps and non-gaps were sensitive to weak light and demonstrated a decreasing trend. The descending trend of Non-photochemical quenching coefficient (NPQ) for C.kawakamii seedlings in forest gaps was larger than that of non-gaps, which indicated that the decline of heat dissipation capacity constrained the growth of seedlings in forest gaps under the weak light condition. Seedlings in forest gaps could maintain a rapid photosynthetic electron transport rate under the weak light condition. This is due to the actual quantum yield of PSII photochemical (Y) showed a tiny decreasing trend in forest gaps than those of non-gaps. We concluded that weak light condition limited the growth of C.kawakamii seedlings at the low age classes of forest gaps and the high age classes of non-gaps. | |||
TO cite this article:TANG Rong,HE Zhongsheng,LIU Jinfu, et al. Effect of Forest Gaps on the Photosynthetic Physiology of Castanopsis kawakamii seedlings[OL].[10 April 2015] http://en.paper.edu.cn/en_releasepaper/content/4637682 |
6. Relationship between fossil chironomid and water depth: a tool for reconstructing past hydroclimatic changes in arid Northwestern China | |||
Jianhui Chen,Enlou Zhang,Stephen J Brooks,Xiaozhong Huang,Haipeng Wang,Jianbao Liu,Fahu Chen | |||
Earth Science 03 March 2014 | |||
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Abstract:A significant relationship between the distribution and abundance of chironomids and water depth has long been recognized. However, few studies have been carried out on this topic in arid regions where the chironomid community is usually controlled by water salinity. Thus Bosten Lake, the largest inland freshwater lake (approx. 1200 km2) in China and located in the northwest of the country, provides a unique opportunity to investigate this relationship in an arid region. A total of 42 surface sediment samples, from water depths of 0 m to 17 m, and 12 chironomid taxa were used in the analysis. The first PCA axis explained 59.3% of the variance in the chironomid assemblage and there was a significant correlation between PCA axis 1 scores and water depth (r2 = 0.84, P < 0.001). The chironomid assemblages significantly changed at 8.0 m. This threshold corresponded to an abrupt change in the underwater slopes and the spatial pattern of aquatic vascular plants. RDA showed that the abundance of Chironomus plumosus-type, Microchironomus and Cryptochironomus was positively correlated with water depth, whereas the abundance of Tanytarsus, Polypedilum nubifer-type, Cricotopus and Psectrocladius sordidellus-type was negatively correlated with water depth. These ecological relationships have been supported by the literature. The qualitative chironomid-inferred changes in lake level and qualitative diatom-inferred changes in salinity from a sediment core BSTC001 were also compared. The close agreement in trends of these two variables validates the use of chironomid assemblages to study palaeo-hydrological variability in this westerly-dominated arid region. | |||
TO cite this article:Jianhui Chen,Enlou Zhang,Stephen J Brooks, et al. Relationship between fossil chironomid and water depth: a tool for reconstructing past hydroclimatic changes in arid Northwestern China[OL].[ 3 March 2014] http://en.paper.edu.cn/en_releasepaper/content/4587934 |
7. Paleomagnetic age constraints and paleoclimate implications from Miocene fine-grained sediments of the Tianshui Basin, western China | |||
ZHANG Jun,LI Jijun,SONG Chunhui,ZHAO Zhijun,XIE Guangpu,WANG Xiuxi,HUI Zhengchuang,PENG Tingjiang | |||
Earth Science 18 September 2012 | |||
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Abstract:Miocene strata from the Tianshui Basin of western China have received intense attention recently because these sediments have been interpreted as some of the earliest loess deposits in eastern Asia. Detection of lower Miocene loess revises the estimated timing of inland Asian desertification from 8 Ma back to 22 Ma. However, strata with diagnostic sedimentary structures irreconcilable with eolian loess are also commonly observed in the Tianshui Basin. Therefore, constraining ages of fine-grained sediments in the Tianshui Baisn will provide a test of recent provocative interpretations about the initiation of inland Asian desertification. Here we date an interval of fine-grained sediments with non-eolian sedimentary structures from the Tianshui Basin and find that age of this succession is quite similar to the purported lower Miocene loess deposits. We argue that more diagnistic provenance tools need be applied to fine-grained Miocene sediments from the Tianshui Basin before one can confidently state that these sediments are indeed loess and inland Asian desertification had occurred by 22 Ma. | |||
TO cite this article:ZHANG Jun,LI Jijun,SONG Chunhui, et al. Paleomagnetic age constraints and paleoclimate implications from Miocene fine-grained sediments of the Tianshui Basin, western China[OL].[18 September 2012] http://en.paper.edu.cn/en_releasepaper/content/4489893 |
8. Implications for OSL dating of young sediments(<100 years old): a comparison of OSL ages with independent ages | |||
Fan Tianlai,Fan Yuxin | |||
Earth Science 03 March 2010 | |||
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Abstract:We explore the use of quartz optically stimulated luminescence dating of young aeolian dust deposits for reconstructing high-resolution chronology on a time scale of decadals. Samples potentially experiencing long/short transpotation are taken from surface layer of buildings on the northern bank of the Yellow River, Lanzhou, China. The maxmium ages of dust deposits are known from historical sources. De values were calculated basing on the luminescent signals measured using SAR protocol in middle aliquots, and range from 0.16 Gy to 1.78 Gy, indicating that the residual luminescent signals can not be ignored. The potential Optical Stimulated Luminescence ages were estimated using dose rate obtained in loess samples on the Loess Plateau in China. And the final results show that even the minimal De components were taken into account, the OSL age of the youngest samples is estimated to be 32 years, which is obviously older than the history of the building. It is thus concluded that luminescent signals of dusts are possibly unbleached before they were buried, however, the Optical Stimulated Luminescence ages and high-resolution chronology can be obtained on time scale of decades. Besides, more caution should be paid to the application of quartz OSL dating on decadal timescale. | |||
TO cite this article:Fan Tianlai,Fan Yuxin. Implications for OSL dating of young sediments(<100 years old): a comparison of OSL ages with independent ages[OL].[ 3 March 2010] http://en.paper.edu.cn/en_releasepaper/content/40386 |
9. Dating of the River Terraces in Eastern Qilian Shan, Northwest China | |||
Pan Baotian,Gao Hongshan,Li Jijun | |||
Earth Science 10 November 2006 | |||
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Abstract:The actively deformed foreland of eastern Qilian Shan (mountains) contains well-preserved geomorphic features such as river terraces and tectonically uplifted alluvial fans, providing suitable archives for research on regional tectonic activities and paleoclimatic changes. These geomorphic surfaces are well dated by using a combination of magnetostratigraphy, electron spin resonance (ESR), thermoluminescence (TL), infra-red stimulated luminescence (IRSL), radiocarbon dating, and correlation with the well-established loess-paleosol sequences of China. Our results show that the age of river terraces is 1.24 Ma, 820~870 ka, 780 ka, 420~440 ka, 230~250 ka, 140 ka, 60 ka and 10 ka, respectively. Repetitive stratigraphic and geomorphic pattern on these terraces indicate that climate variations play a significant role in controlling regional fluvial geomorphic evolution, even within this tectonic active regions. | |||
TO cite this article:Pan Baotian,Gao Hongshan,Li Jijun. Dating of the River Terraces in Eastern Qilian Shan, Northwest China[OL].[10 November 2006] http://en.paper.edu.cn/en_releasepaper/content/9456 |
10. DEM-based Watershed Topographic Attributes Extraction and Analysis | |||
Yuan Lifeng,Zhang Youshui | |||
Earth Science 03 November 2005 | |||
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Abstract:n this paper we took Yan’er Gully watershed for an analysis instance, using ArcGIS software as a digital terrain analysis tool for studying topographic attributes extraction and analysis methods based on grid DEMs. The spatial and statistical distribution of topographic attributes were computed and compared. We assumed that a relative real DEM which is consistent with natural land surface can be produced through reconditioning basic material generated DEM and reprocessing DEM. We used mathematic statistics method and comparative analysis method to analyze effect of DEMs with different resolutions on the outcome of topographic terrain extraction, including elevation, slope, topographic index (i.e. ln (α/tan β)), watershed and subwatershed area, and drainage network. The analysis results of effect of DEM with different resolution on topographic attributes derived form DEMs indicated that terrain is smoothed, the mean value of slope decreases, the mean value of ln(α/tanβ) distribution i | |||
TO cite this article:Yuan Lifeng,Zhang Youshui. DEM-based Watershed Topographic Attributes Extraction and Analysis[OL].[ 3 November 2005] http://en.paper.edu.cn/en_releasepaper/content/3488 |
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