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| 1 | Multichannel singular spectrum analysis of the axial atmospheric angular momentum显示文摘Earth's variable rotation is mainly produced by the variability of the AAM(atmospheric angular momentum). In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth's rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD(length of day) were described. We applied MSSA(Multichannel Singular Spectrum Analysis) jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs(Principal components) strongly related to ENSO(El Nino southern oscillation) were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability. | Leonid Zotov N.S.Sidorenkov Ch.Bizouard C.K.Shum Wenbin Shen | 2017 | Geodesy and Geodynamics2017，8，6： | 3 |
| 2 | A possible interrelation between Earth rotation and climatic variability at decadal time-scale显示文摘Using multichannel singular spectrum analysis(MSSA) we decomposed climatic time series into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic oscillations have been found in the global mean Earth temperature anomaly(Had CRUT4) and global mean sea level(GMSL). Similar cycles were also found in Earth rotation variation.Over the last 160 years multi-decadal change of Earth's rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth's rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes. | Leonid Zotov C.Bizouard C.K.Shum | 2016 | Geodesy and Geodynamics2016，7，3： | 2 |
| 3 | 精密定轨用地球大气模型误差的补偿方法显示文摘本文提出了一种用于精密轨道确定的地球大气模型误差的补偿方法,这种方法采用改进 大气周日峰角的技术,有效地补偿了大气密度模型的误差,并具有较好的物理意义.与传统 的每圈改进一次加速度的方法比较,轨道确定达到了相当的径向精度,且避免了轨道改进参 数间的相关性,同时解算参数的数量也少了一半. | 汤锡生 C.K.Shum | 1997 | 天文学报1997，38，3： | 2 |
| 4 | 利用海洋重力场变化分析洋底板块运动显示文摘洋底板块运动是地球动力学和全球变化研究的重要内容.本文根据质量迁移与地球外部重力场变化的对应关系,利用不同时期测高资料推算的1995-2019全球海洋重力场变化结果,反演分析全球洋底板块运动特征.研究表明,板块汇聚边界、板块内无震海岭、海山群、断裂带等区域重力异常变化显著,而在板块离散边界无明显变化趋势;西南印度洋中脊、大西洋中脊、中印度洋中脊等地区重力异常垂直梯度变化显著,且在西太平洋俯冲带、部分海岭区域也存在明显变化,其空间分布与地形基本吻合.海洋重力场变化整体上准确反映了全球洋底板块构造运动.相较于重力异常变化反演结果,重力垂直梯度的变化能够更为准确地反映洋底板块运动特征,特别是在洋中脊区域,扩张速率越小,垂直重力梯度变化越显著.此外,详细讨论了测高海洋重力场不确定因素对洋底板块运动分析结果的影响,海面坡度改正是主要因素之一. | 李倩倩 鲍李峰 C.K.Shum | 2020 | 地球物理学报2020，63，7： | 2 |
| 5 | 在非球形引力摄动下金星轨道器运动的分析解显示文摘给出了行星轨道器在慢自转中心天体 (如金星、水星等 )非球形引力摄动下运动的分析摄动解 ,它适用于 0 | 刘林 C.K.Shum | 1999 | 中国科学(A辑)1999，29，10： | 1 |
| 6 | Analytic perturbation solutions to the Venusian orbiter due to the nonspherical gravitational potential显示文摘The analytic perturbation solutions to the motions of a planetary orbiter given in this paper are effective for0< e< 1, where e is the orbital eccentricity of the orbiter. in the solution, it is as-sumed that the rotation of the central body is slow, and its astronomical background is clear. Examples for such planets in the solar system are Ven黶 and Mercury. The perturbation solution is tested numer-ically on two Venusian orbiters with eccentric orbits, PVO and Magellan, and found to be effective. | 刘林 C.K.Shum | 2000 | Science China Mathematics2000，43，5： | 1 |
| 7 | The rigorous adjustment of the global mean sea level budget during 2005-2015显示文摘Global mean sea level budget is rigorously adjusted during the period 2005-2015.The emphasis is to provide the best estimates for the linear rates of changes(trends)of the global mean sea level budget components during this period subject to the constraint:Earth’s hydrosphere conserves water.The newly simultaneously adjusted trends of the budget components suggest a larger correction for the global mean sea level trend implicated by the other budget components’trends under the budget constraint.The simultaneous estimation of the linear trends of the budget components subject to the constraint for closure improves their uncertainties and enables a holistic assessment of the global mean sea budget,which has implications for future sea level science studies,including the future Intergovernmental Panel on Climate Change(IPCC)Assessment Reports,and the US Climate Assessment Reports. | H.Bâki Iz T.Y.Yang C.K.Shum | 2021 | Geodesy and Geodynamics2021，12，3： | 0 |
| 8 | Characterizing receiver clock behaviors onboard Low Earth Orbiters:A case study of GRACE satellites显示文摘Accurate estimation of clocks, for example for the Gravity Recovery And Climate Experiment(GRACE)twin-satellites, is a critical part of precise orbit determination(POD) that ensures temporal gravity inversion. Characterizing the periodic variations of the receiver clocks is critical for precise clock modeling and prediction. In this study, the receiver clock is estimated using two different POD procedure: kinematic and reduced-dynamic approaches. Choices and the number of orbital parameters estimated in POD process affect the clock estimates, e.g., there are 8895 and 34,560 total parameters in the reduced-dynamic and kinematic approaches, respectively. In the both cases, the periodic variations of GRACE receiver clock are mainly dominated by the GPS orbit period, as well as once-(1-pr) and twiceper-revolution(2-pr) effects. Here the 1-pr effect is coupled with the relativistic effect, resulting in a difficulty to separate both signals. The clock amplitudes caused by the GPS orbit period, 1-pr and 2-pr are about 0.1, 0.03 and 0.01 ns, respectively. The GPS orbit period is almost one order magnitude larger than the 1-and 2-pr effect. The 0.1-ns amplitude of the 12-h periodic variation is equivalent to a 3-cm error in range. Such a systematic error should be considered in the receiver clock modeling for both the improvement of positioning accuracy and the reduction of number of unknown parameters, if the precise point positioning(PPP) technique is used for the orbit determination of the GRACE. | Tzu-Pang Tseng C.K.Shum Ting-Yi Yang | 2019 | Geodesy and Geodynamics2019，10，4： | 0 |
| 9 | Antarctic-wide annual ice flow maps from Landsat 8 imagery between 2013 and 2019显示文摘Ice velocity constitutes a key parameter for quantifying ice-sheet discharge rates and is thus crucial for improving the coupled models of the Antarctic ice sheet towards accurately predict its contribution to future global sea-level rise.However,in Antarctica,high-resolution and continuous ice velocity estimates remain elusive,which is key to unravel Antarctica’s present-day ice mass balance processes.Here,we present a suite of newly estimated Antarctic-wide,annually-sampled ice velocity products at 105-m grid-spacing observed by Landsat 8 optical images data.We first describe a procedure that can automatically calibrate and integrate ice displacement maps to generate Antarcticwide seamless ice velocity products.The annual ice velocity mosaics are assembled using a total of 250,000 displacement maps inferred from more than 80,000 Landsat 8 images acquired between December 2013 and April 2019.The new annual Antarctic ice velocity data product exhibits an improved quantification of near-decadal Antarctic-wide ice flow,and an opportunity to investigate ice dynamics at a higher spatial resolution and annual sampling,as compared to existing data products.Validation studies confirmed improved accuracy and consistency of this new data product,when compared with independently estimated optical and radar ice velocity data products,as well as in situ data. | Qiang Shen Hansheng Wang C.K.Shum Liming Jiang Houtse Hsu Fan Gao Yingli Zhao | 2021 | International Journal of Digital Earth2021，14，5： | 0 |
| 10 | 地球重力场的时间变化显示文摘目前人们对地球物理、大气现象引起重力场变化的原因及影响还不是十分清楚.地球重力场反映了组成地球全部物质的分布.重力场的变化是由固体地球运动引起的,这种运动与太阳、月亮相互吸引(潮汐)有关.也与由气候变化引起的大气、海洋、极冰盖和地下水变化相互影响有关.这些变化影响地球转动.改变地球卫星轨道.引起海平面变化并且间接地影响全球气候. | C.K.Shum R.J.Eanes 刘爱国 | 1992 | 地球物理学进展1992，，2： | 0 |
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