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Nitrogen addition promotes soil carbon accumulation globally

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science China Life sciences 2025年第1期 284-293页

作者： Xuemei Yang suhui Ma Erhan Huang Danhua Zhang Guoping Chen Jiangling Zhu Chengjun Ji Biao Zhu Lingli Liu Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Ministry of Education key laboratory for Transboundary Ecosecurity of southwest China School of Ecology and Environmental ScienceYunnan University state key laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences

soil is the largest carbon(C) reservoir in terrestrial ecosystems and plays a crucial role in regulating the global C cycle and climate *** nitrogen(N) deposition has been widely considered as a critical factor affecting soil organic carbon(sOC) storage, but its effect on sOC components with different stability remains unclear. Here, we analyzed extensive empirical data from 304 sites worldwide to investigate how sOC and its components respond to N addition. Our analysis showed that N addition led to a significant increase in bulk sOC(6.7%), with greater increases in croplands(10.6%) and forests(6.0%) compared to grasslands(2.1%). Regarding sOC components, N addition promoted the accumulation of plant-derived C(9.7%–28.5%) over microbial-derived C(0.2%), as well as labile(5.7%) over recalcitrant components(–1.2%), resulting in a shift towards increased accumulation of plant-derived labile C. Consistently, N addition led to a greater increase in particulate organic C(11.9%) than mineral-associated organic C(3.6%), suggesting that N addition promotes C accumulation across all pools, with more increase in unstable than stable pools. The responses of sOC and its components were best predicted by the N addition rate and net primary productivity. Overall, our findings suggest that N enrichment could promote the accumulation of plant-derived and non-mineral associated C and a subsequent decrease in the overall stability of soil C pool, which underscores the importance of considering the effects of N enrichment on sOC components for a better understanding of C dynamics in soils.

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An Adaptive 2D Planar Projection and Its Application in Geoscience studies

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Journal of earth science 2015年第5期26卷 724-728页

作者： Yong Zheng Bikai Jin Xiong Xiong sidao Ni state key laboratory of geodesy and earth's dynamics Institute of Geodesy and GeophysicsChinese Academy of Sciences

A linear projection approach is developed to present geoscience research result in planar coordinate system projected from spherical coordinate system. Here, the sphere is intersected by a plane and its surface is projected onto the plane. In order to keep the projected coordinate system orthogonal, and minimize the distortion, one axis of the planar coordinate system is chosen in our projection based on the shape of the region to be projected, and the other axes can be chosen arbitrarily or based on the constraint of the orthogonality. In the new method the projection is self-contained. The forward projection can be fully projected backward without loss of precision. The central area of the sphere will be projected to the planar system without distortion, and the latitudinal length in the rotated spherical system keeps constant during the projecting process. Only the longitudinal length in the rotated spherical system changes with the rotated latitude. The distortion of the projection therefore, overall, is small and suitable for geoscience studies.

关键词： adaptive 2D projection linear planar geoscience

Physical analysis on improving the recovery accuracy of the earth's gravity field by a combination of satellite observations in along-track and cross-track directions

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Chinese Physics B 2014年第10期23卷 633-640页

作者：郑伟许厚泽钟敏员美娟 state key laboratory of geodesy and earth’s dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences College of science Wuhan University of Science and Technology

The physical investigations on the accuracy improvement to the measurement of the earth＇s gravity field recovery are carried out based on the next-generation Pendulum-A/B out-of-plane twin-satellite formation in this paper. Firstly, the earth＇s gravity field complete up to degree and order 100 is, respectively, recovered by the collinear and pendulum satellite formations using the orbital parameters of the satellite and the matching accuracies of key payloads from the twin GRACE satellites. The research results show that the accuracy of the earth＇s gravity field model from the Pendulum-A/B satellite formation is about two times higher than from the collinear satellite formation, and the further improvement of the determination accuracy of the earth＇s gravity field model is feasible by the next-generation Pendulum-A/B out-of-plane twin-satellite formation. secondly, the earth＇s gravity field from Pendulum-A/B complete up to degree and order 100 is accurately recovered based on the orbital parameters of the satellite （e.g., an orbital altitude of 400 km, an intersatellite range of 100 km, an orbital inclination of 89° and an orbital eccentricity of 0.001）, the matching accuracies of space- borne instruments （e.g. 10-6 m in the intersatellite range, 10-3 m in the orbital position, 10-6 m/s in orbital velocity, and 10-11 m/s2 in non-conservative force）, an observation time of 30 days and a sampling interval of 10 s. The measurement accuracy of the earth＇s gravity field from the next-generation Pendulum-A/B out-of-plane twin-satellite formation is full of promise for being improved by about l0 times compared with that from the current GRACE satellite formation. Finally, the physical requirements for the next-generation Pendulum-A/B out-of-plane twin-satellite formation are analyzed, and it is proposed that the satellite orbital altitude be preferably designed to be close to 400±50 km and the matching precision of key sensors from the Pendulum-A/B mission be about one ord

关键词： twin pendulum-MB satellites collinear and pendulum satellite formations along-cross-track ob-servations physical analysis satellite gravity recovery

A contrastive study on the influences of radial and three-dimensional satellite gravity gradiometry on the accuracy of the earth's gravitational field recovery

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Chinese Physics B 2012年第10期21卷 577-584页

作者：郑伟许厚泽钟敏员美娟 state key laboratory of geodesy and earth's dynamics Institute of Geodesy and GeophysicsChinese Academy of Sciences Department of Applied Physics Wuhan University of Science and Technology

The accuracy of the earth＇s gravitational field measured from the gravity field and steady-state ocean circulation explorer（GOCE）,up to 250 degrees,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij from the satellite gravity gradiometry（sGG） are contrastively demonstrated based on the analytical error model and numerical simulation,***,the new analytical error model of the cumulative geoid height,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij are established,*** 250 degrees,the GOCE cumulative geoid height error measured by the radial gravity gradient V zz is about 2 1/2 times higher than that measured by the three-dimensional gravity gradient V ***,the earth＇s gravitational field from GOCE completely up to 250 degrees is recovered using the radial gravity gradient V zz and three-dimensional gravity gradient V ij by numerical simulation,*** study results show that when the measurement error of the gravity gradient is 3×10 12 /s 2,the cumulative geoid height errors using the radial gravity gradient V zz and three-dimensional gravity gradient V ij are 12.319 cm and 9.295 cm at 250 degrees,*** accuracy of the cumulative geoid height using the three-dimensional gravity gradient V ij is improved by 30%-40% on average compared with that using the radial gravity gradient V zz in 250 ***,by mutual verification of the analytical error model and numerical simulation,the orders of magnitude from the accuracies of the earth＇s gravitational field recovery make no substantial differences based on the radial and three-dimensional gravity gradients,***,it is feasible to develop in advance a radial cold-atom interferometric gradiometer with a measurement accuracy of 10 13 /s 2-10 15 /s 2 for precisely producing the next-generation GOCE Follow-On earth gravity field model with a high spatial resolution.

关键词： GOCE GOCE Follow-On radial and three-dimensional gravity gradients satellite gravity gradiometry earth's gravitational field

Efficient and rapid accuracy estimation of the earth's gravitational field from next-generation GOCE Follow-On by the analytical method

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Chinese Physics B 2013年第4期22卷 563-570页

作者：郑伟许厚泽钟敏刘成恕员美娟 state key laboratory of geodesy and earth's dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Department of Applied Physics Wuhan University of Science and Technology

Firstly, a new analytical error model of the cumulative geoid height using the three-dimensional diagonal tensors of satellite gravity gradiometry （sGG） is introduced based on the variance-covariance matrix principle. secondly, a study for the requirements demonstration on the next-generation GOCE Follow-On satellite gravity gradiometry system is developed using different satellite orbital altitudes and measurement accuracies of satellite gravity gradiometer by the new analytical error model of sGG. The research results show that it is preferable to design satellite orbital altitudes of 300 km–400km and choose the measurement accuracies of 10-13/s2 –10-15/s2 from satellite gravity gradiometer. Finally, the complementarity of the four-stage satellite gravity missions, including past CHAMP, current GRACE, and GOCE, and next-generation GOCE Follow-On, is contrastively demonstrated for precisely recovering the earth’s full-frequency gravitational field with high spatial resolution.

关键词： GOCE Follow-On satellite analytical method requirements demonstration satellite gravity gradiometry earth’s gravitational field

seismic attenuation in the lower mantle beneath Northeast China constrained from short-period reflected core phases at short epicentral distances

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earth and Planetary Physics 2019年第6期3卷 537-546页

作者： BaoLong Zhang siDao Ni YuLin Chen state key laboratory of geodesy and earth’s dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences

The thermal structure of the lower mantle plays a key role in understanding the dynamic processes of the earth's evolution and mantle *** intrinsic attenuation in the lower mantle is highly sensitive to temperature,determining of the attenuation of the lower mantle could help us determine its thermal *** attempted to constrain the attenuation of the lower mantle by measuring the amplitude ratios of p to scP on the vertical component and s to scs on the tangential component at short epicentral distances for seismic wave data from deep earthquakes in Northeast *** calculated the theoretical amplitude ratios of p to scP and s to scs by using ray theory and the axial-symmetric spectral element method AxisEM,as well as by considering the effects of radiation patterns,geometrical spreading,and scP reflection *** comparing the observed amplitude ratios with the synthetic results,we constrained the quality factors as Qα≈3,000 and Qβ≈1,300 in the lower mantle beneath Northeast China,which are much larger than those in the preliminary reference earth model(PREM)model of Qα~800 and Qβ~*** propose that the lower mantle beneath Northeast China is relatively colder than the average mantle,resulting in weaker intrinsic attenuation and higher *** estimated the temperature of the lower mantle beneath Northeast China as approximately 300–700 K colder than the global average value.

关键词： seismic attenuation lower mantle Northeast China reflected core phases thermal state

Finite difference calculation of traveltime on non-orthogonal grid

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earthquake science 2018年第2期31卷 55-61页

作者： Xiangfang Zeng sidao Ni state key laboratory of geodesy and earth's dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences

Finite difference methods have been widely employed in solving the eikonal equation so as to calculate traveltime of seismic phase. Most previous studies used regular orthogonal grid. However, much denser grid is required to sample the interfaces that are undulating in depth direction, such as the Moho and the 660 km *** we propose a new finite difference algorithm to solve the eikonal equation on non-orthogonal grid（irregular grid）.To demonstrate its efficiency and accuracy, a test was conducted with a two-layer model. The test result suggests that the similar accuracy of a regular grid with ten times grids could achieve with our new algorithm, but the time cost is only about 0.1 times. A spherical earth model with an undulant660 km discontinuity was constructed to demonstrate the potential application of our new method. In that case, the traveltime curve fluctuation corresponds to topography. Our new algorithm is efficient in solving the first arrival times of waves associated with undulant interfaces.

关键词： finite difference traveltime non-orthogonal grid topography

Rupture Process of the M_s 7.0 Lushan earthquake Determined by Joint Inversion of Local static GPs Records, strong Motion Data, and Teleseismograms

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Journal of earth science 2017年第2期28卷 404-410页

作者： Jun Li Chengli Liu Yong Zheng Xiong Xiong state key laboratory of geodesy and earth's dynamics Institute of Geodesy and Geophysics CAS Hubei subsurface Multi-scale Imaging key laboratory Institute of Geophysics and Geomatics China University of Geosciences

On April 20, 2013, an M_s 7.0 earthquake struck Lushan County in sichuan Province, China, and caused serious damage to the source region. We investigated the rupture process of the M_s7.0 Lushan earthquake by jointly inverting waveforms of teleseismic P waveforms and local strong motion records as well as static GPs observations. The inverted results indicate that the rupture of this earthquake was dominated by the failure of an asperity with a triangular shape and that the main shock was dominated by thrust slip. The earthquake released a total seismic moment of 1.01× 10^（19）Nm, with 92% of it being released during the first 11 s. The rupture had an average slip of 0.9 m and produced an average stress drop of 1.8 MPa. Compared with our previous work that was based mainly on a unique dataset, this joint inversion result is more consistent with field observations and the distribution of aftershock zones.

关键词： GPs Longmenshan Lushan earthquake rupture process strong motion

Rapid earthquake focal mechanism inversion using high-rate GPs velometers in sparse network

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science China earth sciences 2015年第11期58卷 1970-1981,1页

作者： GUO AiZhi NI siDao CHEN WeiWen Jeffrey T.FREYMUELLER sHEN ZhiChao state key laboratory of geodesy and earth's dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences school of earth and space sciences University of Science and Technology of China Geophysical Institute University of Alaska Fairbanks

In this study, we demonstrate an approach for inverting earthquake source parameters based on high-rate global positioning system （GPs） velocity seismograms. The velocity records obtained from single-station GPs velocity solutions with broadcast ephemeris are used directly for earthquake source parameter inversion using the Cut and Paste method, without requiring conversion of the velocity records into displacement records. Taking the E1 Mayor-Cucapah earthquake as an example, GPs velocity records from 10 stations with reasonable azimuthal coverage provide earthquake source parameters very close to those from the Global centroid moment tensor （Global CMT） solution. In sparse network tests, robust source parameters with acceptable bias can be achieved with as few as three stations. When the number of stations is reduced to two, the bias in rake angle becomes appreciable, but the magnitude and strike estimations are still robust. The results of this study demonstrate that rapid and reliable estimation of earthquake source parameters can be obtained from GPs velocity data. These parameters could be used for early earthquake warning and shake map construction, because such GPs velocity records can be obtained in real time.

关键词： high-rate GPs velometer GPs velocity determination CAP method earthquake source parameters sparse network