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We explore the variations of Rayleigh wave phase velocity beneath eastern China in a broad period range (20–200 s). Rayleigh wave dispersion curves are measured by the two-station technique for a total of 734 interstation paths u...
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We explore the variations of Rayleigh wave phase velocity beneath eastern China in a broad period range (20–200 s). Rayleigh wave dispersion curves are measured by the two-station technique for a total of 734 interstation paths using vertical component broadband waveforms at 39 seismic stations in eastern China from 466 global earthquakes. In addition, 599 waveform inversion interstation measurements were added to this data set. The interstation dispersion curves are then inverted for high-resolution isotropic and azimuthally anisotropic phase velocity maps at periods between 20 and 200 s. At shorter periods sampling the crustal depth range, phase velocities are higher in the southeastern part of the region, reflecting the thinner crust there. The Jiangnan Belt separates Cathaysia from the Yangtze Craton, the latter with thicker crust and a deep, high-velocity cratonic root. The eastern part of Yangtze Craton, however, east of 115–116?E, does not display a deep root and has a thin lithosphere. Azimuthal anisotropy at long periods (>120 s) shows fast propagation directions broadly similar to that of the absolute plate motion. Beneath Cathaysia and eastern Yangtze Craton, anisotropy in the asthenosphere is strong and suggests coast-perpendicular flow. Asthenospheric flow from beneath China’s thick continental lithosphere toward the thinner lithosphere of the margin and the resulting decompression melting may be the fundamental causes of the intraplate basaltic volcanism along the eastern coast of China.
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Post-orogenic mafic dikes are widespread across eastern Shandong Province, North China Craton, eastern China. We here report new U-Pb zircon ages and bulk-rock geochemical and Sr-Nd-Pb isotopic data for representative samples of t...
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Post-orogenic mafic dikes are widespread across eastern Shandong Province, North China Craton, eastern China. We here report new U-Pb zircon ages and bulk-rock geochemical and Sr-Nd-Pb isotopic data for representative samples of these rocks. LA-ICP-MS U-Pb zircon analysis of two mafic dike samples yields consistent ages of 118.7 ± 0.25 million years and 122.4 ± 0.21 million years. These Mesozoic mafic dikes arc characterized by high (~(87)Sr/~(86)Sr)_i ranging from 0.7082 to 0.7087, low ε_(Nd)(t) values from -17.0 to -17.5, ~(206)Pb/~(204)Pb from 17.14 to 17.18, ~(207)Pb/~(204)Pb from 15.44 to 15.55, and ~(208)Pb/~(204)Pb from 37.47 to 38.20. Our results suggest that the parental magmas of these dikes were derived from an ancient, enriched lithospheric mantle source that was metasomatized by foundered lower crustal eclogitic materials prior to magma generation. The mafic dikes underwent minor fractionation during ascent and negligible crustal contamination. Combined with previous studies, these findings provide additional evidence that intense lithospheric thinning beneath eastern Shandong occurred at -120 Ma, and that this condition was caused by the removal/foundering of the lithospheric mantle and lower crust.
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Satellite data (MODIS, GOME, and MOPITT) together with a chemical transport global model of the atmosphere (MOZART-2) are used to characterize air pollution in Eastern China and the Eastern US to assess the differences between the...
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Satellite data (MODIS, GOME, and MOPITT) together with a chemical transport global model of the atmosphere (MOZART-2) are used to characterize air pollution in Eastern China and the Eastern US to assess the differences between the photochemical conditions in these two regions. Observations show that aerosol concentrations (both fine (radius < 0.5 μm) and coarse modes (radius > 0.5 μm)) are higher in Eastern China than in the Eastern US. The NO_x concentrations in both regions are substantially higher than in remote regions such as over the oceans (150 compared to 5 (10~(14)#cm~(-2)) over the Pacific Ocean). The CO concentrations are high in both urbanized areas (30 compared to 10 (10~(17)#cm~(-2)) over the Pacific Ocean). However, the concentrations of non-methane hydrocarbons from both anthropogenic and biogenic sources are considerably lower in Eastern China than in the Eastern US. As a result, the rate of photochemical ozone production and ozone concentrations during summer is significantly lower in Eastern China (daily averaged concentrations of 40-50 ppbv in summer) than in the Eastern US (daily averaged values of 60-70 ppbv). The analysis also shows that in Eastern China, the O_3 production is mainly due to the oxidation of carbon monoxide (54% of total O_3 production), while, in the Eastern US, the O_3 production is attributed primarily to the oxidation of reactive hydrocarbons (68% of total O_3 production). The results also indicate that biogenic emissions of hydrocarbons contribute substantially to the production of O_3 in the Eastern US. The O_3 production due to the oxidation of biogenic hydrocarbons represents approximately one third of total O_3 photochemical production in this region. Measurements of surface ozone in the Eastern US and Eastern China seem to support that the summer ozone production is lower in Eastern China than in the Eastern US. However, additional surface measurements, especially of reactive hydrocarbons and ozone are needed in Eastern China in order to improve the present analysis and to confirm our current conclusions. A sensitivity study shows that with increase in anthropogenic emissions of HCs, the surface ozone concentrations significantly increase in Eastern China, indicating that the increase in the emissions of HCs plays an important role for the enhancement in surface ozone in this region.
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Potassium (K), calcium (Ca), and magnesium (Mg) are essential nutrients that have important biological and ecological functions. However, little is known about the large-scale patterns of soil K, Ca, and Mg concentrations across u...
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Potassium (K), calcium (Ca), and magnesium (Mg) are essential nutrients that have important biological and ecological functions. However, little is known about the large-scale patterns of soil K, Ca, and Mg concentrations across urban forests that provide crucial ecosystem services. By measuring total K, Ca, and Mg concentrations of topsoil samples (0-10 and 10-20 cm) from forest patches in 27 urban parks across nine large cities in eastern China, we analyzed their spatial trends and main drivers. Our results indicate a decrease of topsoil K concentration in urban forests from cities in the north to cities in the south, while topsoil Ca and Mg concentrations both showed a unimodal trend along with the latitude. The spatial trend of topsoil K concentration was mainly explained by mean annual temperature (MAT) and preurban soil order, while the spatial variations of topsoil Ca and Mg concentrations both were controlled by mean annual precipitation (MAP) and MAT. Other factors, including nitrogen deposition, gross domestic product per capita, the area and age of each park had an unimportant role in shaping the spatial trends of topsoil K, Ca, and Mg concentrations. Our findings suggest a predominant control of climate on the large-scale patterns of topsoil K, Ca, and Mg concentrations in urban forests and highlight a risk of base cationic nutrient deficiencies in urban forests in southern China.
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The 2011 Tohoku earthquake (M_w 9.0) in Japan caused significant coseismic displacement in much of eastern China, where seismic activity has been intense and damaging earthquakes numerous. Did the Tohoku earthquake change the stre...
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The 2011 Tohoku earthquake (M_w 9.0) in Japan caused significant coseismic displacement in much of eastern China, where seismic activity has been intense and damaging earthquakes numerous. Did the Tohoku earthquake change the stress field and seismic activity in eastern China? Here, we used a viscoelastic deformation model of layered spherical earth to calculate the coseismic and postseismic displacements and compared the results with Global Positioning System data for eastern China. Using the best-fitting model, we then calculated the coseismic and postseismic Coulomb stress changes on major active faults in eastern China. Our results show that the Coulomb stress changes caused by the Tohoku earthquake on these faults are less than 0.002 MPa, so were unlikely to significantly alter the stress field or trigger earthquakes in eastern China.
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The mantle transition zone (MTZ) structure beneath eastern China is studied by using P-wave receiver functions. The 410 km discontinuity is relatively flat whereas the depth of the 660 km discontinuity varies significantly under t...
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The mantle transition zone (MTZ) structure beneath eastern China is studied by using P-wave receiver functions. The 410 km discontinuity is relatively flat whereas the depth of the 660 km discontinuity varies significantly under the study area. This indicates that the 660 is more influenced by laterally varying temperature. The 520 km discontinuity is continuously observed at ～520 km depth under a limited area. Within the South China Block, the MTZ thickness under the Yangtze Craton is larger than normal whereas that under the Cathaysia Block is nearly normal. This indicates colder temperature affecting the MTZ beneath the Yangtze Craton. Combined with seismic tomography, our result suggests that the stagnant ancient slab beneath eastern China is mainly trapped around the base of the MTZ beneath the Yangtze Craton in the study area.
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Fire activity and its environmental effects in eastern China were studied using satellite and surface observations. First, seasonal and interannual variations of fire activity were investigated based on the fire occurrence data fr...
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Fire activity and its environmental effects in eastern China were studied using satellite and surface observations. First, seasonal and interannual variations of fire activity were investigated based on the fire occurrence data from the Moderate Resolution Imaging Spectroradiometer measurements during July 2003 to December 2012. Second, an extraordinarily active agricultural fire season in June 2012 was revealed in mid-eastern China (MEC, 32°N-35°N, 115°E-120°E), where fire pixel density was twice the decadal average and the smoke layer height was observed to be 4 ~ 5 km. Third, significant effects of this fire season on the atmospheric environment were characterized using a combination of ground and satellite data. Crop fires enhanced aerosol optical depth (AOD), nitrogen dioxide (NO_2), and carbon monoxide (CO) amounts near the source and in downwind regions by ~15-60%. A combination of observations and model simulations is required for better understanding effects of crop fires on atmospheric environment and climate. Key Points Variability of fire activity in eastern China was revealed.An extraordinarily active agricultural fire season was observed in June 2012Effects of this fire season on the atmospheric environment were studied
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Clematis erectisepala, a new species of Ranunculaceae collected from Yanjing Village of Markam County in eastern Tibet, is described and illustrated. It is distinguished from other Clematis by its nodding yellow flowers with erect...
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Clematis erectisepala, a new species of Ranunculaceae collected from Yanjing Village of Markam County in eastern Tibet, is described and illustrated. It is distinguished from other Clematis by its nodding yellow flowers with erect sepals and glabrous stamens. This new species is similar to C. brevicaudata DC. vegetatively, but differs from the latter in floral structure.
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Background There were limited studies specifically evaluating whether the difference of the prevalence of sarcopenia exists in men and women in older adults from rural areas in China. The aim of this study was to compare the preva...
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Background There were limited studies specifically evaluating whether the difference of the prevalence of sarcopenia exists in men and women in older adults from rural areas in China. The aim of this study was to compare the prevalence of sarcopenia between men and women in a rural area in eastern China and to explore the underlying causes. Methods This study included 1,105 participants aged 60-89 years. Muscle mass was measured by bio-electrical impedance analysis. Hand grip strength was measured by Jamar Hydraulic Hand Dynamometer. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia-2019 Consensus. Data were analyzed using log-binomial and linear regression. Results The prevalence of sarcopenia was 21.7% in women and 12.9% in men among the study cohort. After adjusting for age, education level, number of diseases, income level, smoking, drinking, and eating habits, proportion of people with sarcopenia was 1.49-fold greater in women than in men (PR = 1.49, 95% CI [1.01–2.26], P?=?0.055). Conclusions The prevalence of sarcopenia in elderly women in this rural area of eastern China is higher than in men, suggesting that women in rural areas in China seem to be more vulnerable for sarcopenia, thus early screening and prevention need to be provided for them to address such gender disparity in health.
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Performance of the Beijing Climate Center Climate System Model (BCC_CSM1.0) insimulating the regional extreme precipitation change over eastern China east of 105°E was eval-uated. Daily observed precipitation data for 1956-2009 a...
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Performance of the Beijing Climate Center Climate System Model (BCC_CSM1.0) insimulating the regional extreme precipitation change over eastern China east of 105°E was eval-uated. Daily observed precipitation data for 1956-2009 at 349 rain gauge stations in China wereused for comparison. The 20th century simulation forced by observed greenhouse gases, aerosols,solar irradiance and volcanic aerosols shows that (1) BCC_CSM1.0 can reproduce the basic fea-ture of observed climatology of annual total precipitation and extreme precipitation over the 95thpercentile, with spatial correlation of 0.77 for both of them. (2) BCC_CSM1.0 is also able to capturethe main change patterns of yearly accumulated extreme precipitation above the 95th percentile,although there are some model biases in the spatial extension and strength. Some model biasesare also noted: (1) Annual total and extreme precipitation south of Yangtze River are underesti-mated. (2) Frequency of heavy precipitation (≥25.0 mm cl~(-1)) over eastern China is underestimated,but the frequency of light rain (0.1 to 9.9 mm d~(-1)) is overestimated. (3) Simulated long-term trendsof annual extreme precipitation amount and frequency in the last 50 yr are the opposite of theobservations in North and South China.
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