期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
GRACE RL05-based ice mass changes in the typical regions of antarctica from 2004 to 2012 被引量:3
1
作者 Ju Xiaolei Shen Yunzhong Zhang Zizhan 《Geodesy and Geodynamics》 2014年第4期57-67,共11页
The Antarctic ice sheet is the largest block of ice on Earth, a tiny change of its ice sheet will have a significant impact on sea level change, so it plays an important role in global climate change. The Gravity Reco... The Antarctic ice sheet is the largest block of ice on Earth, a tiny change of its ice sheet will have a significant impact on sea level change, so it plays an important role in global climate change. The Gravity Recovery and Climate Experiment (GRACE) mission, launched in 2002, provides an alternative method to monitor the Antarctic ice mass variation. The latest Release Level 05 ( RL05 ) version of GRACE time-variable gravity (TVG) data, derived from GRACE observations with improved quality and time-span over 10 years, were released by three GRACE data centers (CSR, JPL and GFZ) in April 2012, which gives us a chance to re-estimate the ice mass change over Antarctic more accurately. In this paper, we examine ice mass changes in regional scale, including Antarctic Peninsula (AP, West Antarctica), Amundsen Sea Embayment (ASE, West Antarctica), Lambert-Amery System (LAS, East Antarctica) and 27 drainage basins based on three data sets. The AP mass change rates are -12.03±0.74 Gt/a (CSR, 2004-2012), -13.92±2.33 Gt/a (JPL, 2004 -2012) , -12.28±0.76 Gt/a (GFZ, 2005-2012) , with an acceleration of -1.50±0.25 Gt/a^2, -1.54±0.26 Gt/a^2, -0. 46±0.28 Gt/a^2 respectively, the ASE mass change rates are -89.22±1.93 Gt/a, -86.28± 2.20 Gt/a, -83.67±1.76 Gt/a with an acceleration of -10. 03±0. 65 Gt/a^2, -8.74±0. 74 Gt/a^2 and -5.69 ±0.68 Gt/a^2, and the LAS mass ehange rates are -4.31±1.95 Gt/a, -7.29±2. 84 Gt/a, 1.20±1.35 Gt/a with an acceleration of -0. 18±0.62 Gt/a^2, 3.55±0.95 Gt/a^2 and 0.97±0.49 Gt/a^2. The mass change rates derived from the three RL05 data are very close to each other both in AP and ASE with the uncertainties much smaller than the change rates, and mass losses are significantly accelerated since 2007 in AP and 2006 in ASE, respectively. However, the mass change rates are significantly different in LAS, negative rate from CSR and JPL data, but positive rate from GFZ data, the uncertainties are even larger than the correspondent change rates. With regard to the 27 drainage basins, seven basins (basin 3-9) located in the east Antarctica show positive mass change rates, and the rest twenty basins are characterized by negative mass change rates during the time span of the three RL05 data. 展开更多
关键词 GRACE Antarctic ice mass change Antarctic Peninsula Amundsen Sea Embayment Lambert-Amery System
下载PDF
Mass change of the Antarctic ice sheet inferred from ICESat and CryoSat-2 被引量:1
2
作者 ZHANG Baojun WANG Zemin +1 位作者 AN Jiachun LIU Yanxia 《Advances in Polar Science》 2017年第3期185-195,共11页
This study examined the mass change of the Antarctic ice sheet(AIS) based on ICESat and CryoSat-2 observations. We estimated the AIS exhibited mass losses of-101±15 Gt·aduring the ICESat period(Sept–Nov 200... This study examined the mass change of the Antarctic ice sheet(AIS) based on ICESat and CryoSat-2 observations. We estimated the AIS exhibited mass losses of-101±15 Gt·aduring the ICESat period(Sept–Nov 2003 to Sept–Oct 2009) and-186±55 Gt·aduring the CryoSat-2 period(Jan 2011 to Dec 2015). Mass losses occurred mainly in the sectors of the Amundsen and Bellingshausen seas. Benefitting from the 30-d subcycle of CryoSat-2, we obtained monthly estimates of mass evolution. Considerable annual variations were observed in the mass evolution sequences and the climatological monthly mass evolution. Seasonal mass evolutions in the sectors of the Bellingshausen and Amundsen seas were found most representative of the annual variation. The geographical distribution characteristics of interannual AIS mass evolution were revealed by the annual average mass evolution sequences. During Jan 2011 to Dec 2015, the ice sheets in the sectors of the Bellingshausen and Amundsen seas, and the Totten Glacier, experienced increasingly rapid areal mass loss. An area of mass gain with a moderate rate of increase was found between Dronning Maud Land and Enderby Land. Rapid mass accumulation has occurred in a limited area of the Kamb Ice Stream. 展开更多
关键词 Antarctic ice sheet mass change mass evolution ICESAT CryoSat-2
下载PDF
Mass and chemical changes of immobile elements in Yamaghan Occurrence, Zanjan Province, Iran 被引量:1
3
作者 I.Vosoughi Niri (Institute of Applied Geophysics, Central South University, Changsha 410083, P.R.China) 《中国有色金属学会会刊:英文版》 CSCD 2001年第4期617-622,共6页
Using mass and chemical changes, behavior of some elements have been evaluated in the study area, Yamaghan Occurrence. The techniques using immobile elements can precisely identify altered volcanic rock precursors and... Using mass and chemical changes, behavior of some elements have been evaluated in the study area, Yamaghan Occurrence. The techniques using immobile elements can precisely identify altered volcanic rock precursors and measure material changes. The rocks of the study area were affected by hydrothermal alteration. Testing of some compatible incompatible and compatible compatible immobile pairs indicates that Al 2O 3 is the most immobile component in the study area. It means that during the three main stages of hydrothermal alteration (phyllic, intermediate argillic and propylitic) aluminum was the most immobile and titanium was slightly immobile. Increases in mass mostly result from mineralization, silicification or carbonatization as voids and other open space fillings and may have replaced the part of glassy matrix. Mass addition has diluted the immobile elements at constant rates. Mass loss is commonly due to leaching of Si, Ca and Na 2O during chloritization and sericitization. The mass loss is recognized by increased proportions of inert minerals such as chlorite and sericite. Mineralographic studies in the study area shows the existence of a supergene zone. Calcocite and covellite are considered enriched minerals. Considering this evidence and mass change results, the enrichment of copper in the circulating fluid is suspected with occasional sulfide precipitation. 展开更多
关键词 mass and chemical changes immobile elements lithogeochemical Yamaghan
下载PDF
Application of Physics Phenomenon Model Towards Economic Symptoms in Indonesia (Spring Oscillation Model and Rupiah Rate Exchange)
4
作者 Kunlestiowati H. Nani Yuningsih Sardjito 《Economics World》 2018年第2期133-141,共9页
A physical phenomenon can be duplicated similarly to different phenomenon. Based on these facts, the application of physics phenomenon model towards the economic cases that occurred in Indonesia will be discussed. Phy... A physical phenomenon can be duplicated similarly to different phenomenon. Based on these facts, the application of physics phenomenon model towards the economic cases that occurred in Indonesia will be discussed. Physical phenomenon to be discussed is the loaded oscillation spring, while the economic case is the dynamics of the Rupiah against foreign currencies, namely U.S. Dollars. Symptoms of the analyzed oscillations involve vibration load on the spring, with the mass load changes against time; for free oscillation, damped oscillation, forced oscillation, as well as forced damped oscillation. Oscillation is modeled into a non homogenous second order differential equation, which results in a solution of the deviation function of time in the form of logarithmic harmonic function. Obtained solutions of physical phenomenon model are matched with the dynamics of the exchange rate data for both steady state, as well as to the condition shortly after the surge (crash). Models are quite satisfactory, especially when being associated with the occurrence of momentary interruption followed by a relaxation mechanism, both for amplitude and period. 展开更多
关键词 spring oscillations mass change exchange rate logarithmic harmonic function
下载PDF
Trends in gravity changes from 2009 to 2013 derived from ground-based gravimetry and GRACE data in North China 被引量:3
5
作者 Shen Chongyang Xuan Songbai +1 位作者 Zou Zhengbo Wu Guiju 《Geodesy and Geodynamics》 2015年第6期423-428,共6页
North China is a key region for studying geophysical progress. In this study, ground-based and Gravity Recovery and Climate Experiment(GRACE) gravity data from 2009 to 2013 are used to calculate the gravity change r... North China is a key region for studying geophysical progress. In this study, ground-based and Gravity Recovery and Climate Experiment(GRACE) gravity data from 2009 to 2013 are used to calculate the gravity change rate(GCR) using the polynomial fitting method. In general, the study area was divided into the Shanxi rift, Jing-Jin-Ji(Beijing-Tianjin-Hebei Province), and Bohai Bay Basin(BBB) regions. Results of the distribution of the GCR determined from ground-based gravimetry show that the GCR appears to be "negativepositive-negative" from west to east, which indicates that different geophysical mechanisms are involved in the tectonic activities of these regions. However, GRACE solutions are conducted over a larger spatial scale and are able to show a difference between southern and northern areas and a mass redistribution of land water storage. 展开更多
关键词 North China Ground-based gravimetry Gravity Recovery and Climate Experiment(GRACE) Polynomial fitting method Gravity changes rate Tectonic activities Geophysical mechanisms mass redistribution
下载PDF
GRACE time-variable gravity and its application to geoscience:Quantitative analysis of relevant literature 被引量:3
6
作者 Cao Liu WenKe Sun 《Earth and Planetary Physics》 EI CSCD 2023年第2期295-309,共15页
The Gravity Recovery and Climate Experiment(GRACE)is the most important gravity satellite to date in human history.Since its launch in 2002,GRACE time-varying gravity has had an unprecedented impact on earth science a... The Gravity Recovery and Climate Experiment(GRACE)is the most important gravity satellite to date in human history.Since its launch in 2002,GRACE time-varying gravity has had an unprecedented impact on earth science and has generated revolutionary changes.Because of natural phenomena such as climate warming,glacial melting,sea level rise,and earthquakes,earth science research has become an increasingly popular discipline in recent years.This article summarizes the importance of GRACE time-varying gravity,its application to geoscience,and its development.We analyzed the historical development and current status of GRACE time-varying gravity as well as research hotspots by searching the literature in the core collection databases of the China National Knowledge Infrastructure and the Web of Science over the past 20 years.The CiteSpace and VOSviewer software packages were applied with reference to the principle of literature metrology.Our investigation and analysis of characteristic indexes,such as the numbers of publications,co-occurrence of keywords,and co-citation of documents,uncovered the wide application and promotion of gravity satellites,especially GRACE time-varying gravity,in earth science.The results showed that the number of publications addressing GRACE data and time-varying gravity theory is increasing annually and that the USA,China,and Germany are the main producers.The Chinese Academy of Sciences,the National Aeronautics and Space Administration of the United States,and the Helmholtz Association of German Research Centres rank among the top three institutions in the world in terms of producing the most publications on this topic.We found that GRACE time-varying gravity plays unique roles in measuring changes in terrestrial water storage changes,ice and snow melting and sea level changes,and(co)seismic gravity changes,as well as in promoting other disciplines. 展开更多
关键词 Gravity Recovery and Climate Experiment(GRACE) Gravity Recovery and Climate Experiment Follow-On(GRACE-FO) time-varying gravity BIBLIOMETRY mass change CiteSpace VOSviewer
下载PDF
Ice rafting history and paleoceanographic reconstructions of Core 08P23 from southern Chukchi Plateau, western Arctic Ocean since Marine Isotope Stage 3 被引量:2
7
作者 ZHANG Taoliang WANG Rujian +4 位作者 XIAO Wenshen CHEN Zhihua CHEN Jianfang CHENG Zhenbo SUN Yechen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第3期68-75,共8页
Multiproxy investigations have been performed on Core 08P23 collected from the Chukchi Plateau, the western Arctic Ocean, during the Third Chinese National Arctic Expedition. The core was dated back to Ma-rine Isotope... Multiproxy investigations have been performed on Core 08P23 collected from the Chukchi Plateau, the western Arctic Ocean, during the Third Chinese National Arctic Expedition. The core was dated back to Ma-rine Isotope Stage (MIS) 3 by a combination of Accelerator Mass Spectrometric (AMS) carbon-14 dating and regional core correlation. A total of five prominent ice-rafted detritus (IRD) events were recognized in MIS 2 and MIS 3. The IRD sources in MIS 3 are originated from vast carbonate rock outcrops of the Canadian Arctic Archipelago and clastic quartz in MIS 2 may have a Eurasian origin. Mostδ18O andδ13C values of Neogloboquadrina pachyderma (sinistral) (Nps) in Core 08P23 are lighter than the average values of surface sediments. The lighterδ18O andδ13C values of Nps in the two brown layers in MIS 1 and MIS 3 were resulted from meltwater events; and those in the gray layers in MIS 3 were caused by the enhanced sea ice formation. Theδ18O values varied inversely withδ13C in MIS 2 indicate that the study area was covered by thick sea ice or ice sheet with low temperature and little meltwater, which prevented the biological productivity and sea-atmosphere exchange, as well as water mass ventilation. The covaried light values ofδ18O andδ13C in MIS 1 and MIS 3 were resulted from meltwater and/or brine injection. 展开更多
关键词 Chukchi Plateau western Arctic Ocean Marine Isotope Stage 3 ice rafted detritus events oxygen and carbon isotope water mass changes
下载PDF
Relation between skeletal muscle volume and prognosis in rectal cancer patients undergoing neoadjuvant therapy 被引量:1
8
作者 Paola De Nardi Alessandro Giani +1 位作者 Giulia Maggi Marco Braga 《World Journal of Gastrointestinal Oncology》 SCIE 2022年第2期423-433,共11页
The prognostic role of body composition indexes,and specifically sarcopenia,has recently been explored in different cancer types.However,conflicting results have been reported.Heterogeneity in cancer type,cancer stage... The prognostic role of body composition indexes,and specifically sarcopenia,has recently been explored in different cancer types.However,conflicting results have been reported.Heterogeneity in cancer type,cancer stage or oncological treatments,as well as different methodology and definition of sarcopenia,could be accounted for different conclusions retrieved from literature.When focusing on colorectal cancer,it clearly appears that colon and rectal cancers are often treated as a single entity though they have different behaviors and treatments.Particularly,patients with advanced rectal cancer represent a peculiar group of patients that according to current guidelines are treated with neoadjuvant chemotherapy and radiotherapy followed by radical surgery.This review was restricted to a homogeneous group of patients with advanced lower rectal cancer and the aim of exploring whether there is a correlation between skeletal muscle depletion and prognosis.Literature was searched for articles related to patients with advanced rectal cancer undergoing neoadjuvant chemo-radiotherapy(NCRT)followed by radical surgery,in whom muscle mass and/or change in muscle mass during neoadjuvant treatment were measured.Eight full-text articles were selected and included in the present review.The main findings of our review were:(1)The majority of the studies defined sarcopenia as muscle mass alone over muscle strength or physical performance;(2)There was a great deal of heterogeneity in the definition and measures of sarcopenia,in the definition of cut-off values,and in the method to measure change in muscle mass;(3)There was not full agreement on the association between sarcopenia at baseline and/or after chemoradiotherapy and prognosis,and only few studies found a significance in the multivariate analysis;and(4)It seems that a loss in skeletal muscle mass during NCRT is associated with the worst outcomes in terms of disease-free survival.In conclusion,analysis of muscle mass might provide prognostic information on patients with rectal cancer,however more robust evidence is needed to define the role of muscle depletion and/or muscle change during neoadjuvant treatments,related to this specific group of patients.If a prognostic role would be confirmed by future studies,the role of preoperative intervention aimed at modifying muscle mass could be explored in order to improve outcomes. 展开更多
关键词 Advanced rectal cancer SARCOPENIA Neoadjuvant treatment CHEMORADIOTHERAPY Surgery Muscle mass change PROGNOSIS SURVIVAL Review
下载PDF
Monthly gravity field solution from GRACE range measurements using modified short arc approach 被引量:4
9
作者 Shen Yunzhong Chen Qiujie Xu Houze 《Geodesy and Geodynamics》 2015年第4期261-266,共6页
In this paper we present a series of monthly gravity field solutions from Gravity Recovery and Climate Experiment(GRACE) range measurements using modified short arc approach,in which the ambiguity of range measureme... In this paper we present a series of monthly gravity field solutions from Gravity Recovery and Climate Experiment(GRACE) range measurements using modified short arc approach,in which the ambiguity of range measurements is eliminated via differentiating two adjacent range measurements.The data used for developing our monthly gravity field model are same as Tongji-GRACEOl model except that the range measurements are used to replace the range rate measurements,and our model is truncated to degree and order 60,spanning Jan.2004 to Dec.2010 also same as Tongji-GRACE01 model.Based on the comparison results of the C_(2,0),C_(2,1),S_(2,1),and C_(15,15),S_(15,15),time series and the global mass change signals as well as the mass change time series in Amazon area of our model with those of Tongji-GRACE01 model,we can conclude that our monthly gravity field model is comparable with Tongji-GRACE01 monthly model. 展开更多
关键词 Satellite geodesy Gravity field model Time-variable gravity field Gravity satellite Gravity Recovery and Climate Experiment (GRACE)Short arc approach Range data mass change Tongji-GRACE01
下载PDF
Global sea level variations from altimetry,GRACE and Argo data over 2005-2014 被引量:3
10
作者 Feng Wei Zhong Min 《Geodesy and Geodynamics》 2015年第4期274-279,共6页
Total sea level variations(SLVs) are caused by two major components:steric variations due to thermal expansion of seawater,and mass-induced variations due to mass exchange between ocean and land.In this study,the g... Total sea level variations(SLVs) are caused by two major components:steric variations due to thermal expansion of seawater,and mass-induced variations due to mass exchange between ocean and land.In this study,the global SLV and its steric and mass components were estimated by satellite altimetry,Argo float data and the Gravity Recovery and Climate Experiment(GRACE) data over 2005-2014.Space gravimetry observations from GRACE suggested that two-thirds of the global mean sea level rise rate observed by altimetry(i.e.,3.1 ± 0.3 mm/a from 2005 to 2014) could be explained by an increase in ocean mass.Furthermore,the global mean sea level was observed to drop significantly during the2010/2011 La Nina event,which may be attributed to the decline of ocean mass and steric SLV.Since early 2011,the global mean sea level began to rise rapidly,which was attributed to an increase in ocean mass.The findings in this study suggested that the global mean sea-level budget was closed from 2005 to 2014 based on altimetry,GRACE,and Argo data. 展开更多
关键词 Sea level variations Gravity Recovery and Climate Experiment (GRACE)Altimetry ArgoOcean mass change La Nina event Steric sea level Sea level budget
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部