Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid heigh...Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.展开更多
The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales(Balaenoptera musculus).From 2014 to 2019,during 6 separate research cruises,the dive behav...The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales(Balaenoptera musculus).From 2014 to 2019,during 6 separate research cruises,the dive behavior of 28 individual blue whales was investigated using bio-logging tags(DTAGs),generating≈190 h of data.Whales dove to significantly greater depths during the day compared to nighttime(day:32.6±18.7 m;night:6.2±2.7 m;P<0.01).During the night,most time was spent close to the surface(86%±9.4%;P<0.01)and at depths of less than 12 m.From 2016 to 2019,active acoustics(scientific echosounders)were used to record prey(euphausiids)density and distribution simultaneously with whale diving data.Tagged whales appeared to perform dives relative to the vertical migration of prey during the day.The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also≈12 m.In recent decades,northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry.Vessel strike risks for large whales are likely underestimated in this region.Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.展开更多
基金supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar(KZCX2-EW-QN114)the National Natural Science Foundation of China(41004006,41131067,11173049 and 41274041)+7 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(Z01101)the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(11-01-02)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of National Administration of Surveying,Mapping and Geoinformation of China(201322)the Open Research Fund Program of the State Key Laboratory of Geoinformation Engineering,China(SKLGIE2013-M-1-5)the Main Direction Program of Institute of Geodesy and Geophysics,Chinese Academy of Sciences(Y309451045)the Research Fund Program of State Key Laboratory of Geodesy and Earth's Dynamics,China(Y309491050)the Research Fund of the National Civilian Space Infrastructure Project(Y419341034)the Research Fund of the Lu Jiaxi Young Talent and the Youth Innovation Promotion Association of Chinese Academy of Science(Y305171017)
文摘Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.
基金supported by the National Key Research and Development Program of China(Grant number 2016YFC0300802)the biodiversity investigation,observation and assessment program(2019-2023)of the Ministry of Ecology and Environment of ChinaIndian Ocean Ninety-east Ridge Ecosystem and Marine Environment Monitoring and Protection,supported by the China Ocean Mineral Resources R&D Association(no.DY135-E2-4).
文摘The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales(Balaenoptera musculus).From 2014 to 2019,during 6 separate research cruises,the dive behavior of 28 individual blue whales was investigated using bio-logging tags(DTAGs),generating≈190 h of data.Whales dove to significantly greater depths during the day compared to nighttime(day:32.6±18.7 m;night:6.2±2.7 m;P<0.01).During the night,most time was spent close to the surface(86%±9.4%;P<0.01)and at depths of less than 12 m.From 2016 to 2019,active acoustics(scientific echosounders)were used to record prey(euphausiids)density and distribution simultaneously with whale diving data.Tagged whales appeared to perform dives relative to the vertical migration of prey during the day.The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also≈12 m.In recent decades,northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry.Vessel strike risks for large whales are likely underestimated in this region.Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.
