Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitati...Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitation prediction. In one of the experiments, the initial snow conditions over the TP were climatological values; while in the other experiment, the initial snow anomalies were snow depth estimates derived from the passive microwave remote-sensing data. In the current study, the difference between these two experiments was assessed to evaluate the impact of initial snow anomalies over the TP on simulated precipitation. The results indicated that the model simulation for precipitation over eastern China had certain improvements while applying a more realistic initial snow anomaly, especially for spring precipitation over Northeast China and North China and for summer precipitation over North China and Southeast China. The results suggest that seasonal prediction could be enhanced by using more realistic initial snow conditions over TP, and microwave remote-sensing snow data could be used to initialize climate models and improve the simulation of eastern China precipitation during spring and summer. Further analyses showed that higher snow anomalies over TP cooled the surface, resulting in lower near- surface air temperature over the TP in spring and summer. The surface cooling over TP weakened the Asian summer monsoon and brought more precipitation in South China in spring and more precipitation to Southeast China during summer.展开更多
We designed two types of pre-adaption plans for this study. One was a pre-adaption training with progressive intermittent hypoxia, with a constant lower pressure oxygen tank used in the plain before arriving at the pl...We designed two types of pre-adaption plans for this study. One was a pre-adaption training with progressive intermittent hypoxia, with a constant lower pressure oxygen tank used in the plain before arriving at the plateau （PG）. The other was by progressively increasing the time of exposure to hypoxia with oxygen supplied in stages after radical plateau （RG）. By testing the blood oxygen saturation （SpO2）, heart rate （HR）, and quality of sleep after arriving at the 3800 m high plateau, results showed that the pre-acclimatization and radical groups performed better than the control group （CG）. Both strategies were equivalent in terms of effects and principles in providing more flexible choices for acclimatization.展开更多
Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the...Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.展开更多
To investigate the tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its surrounding areas,we selected over 1,500 focal mechanism solutions of inland earthquakes(epicenter locates at ...To investigate the tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its surrounding areas,we selected over 1,500 focal mechanism solutions of inland earthquakes(epicenter locates at least 100 km to the coastlines)from Global Centroid Moment Tensor(GCMT)project and analyzed the values of tidal normal and shear stress as well as tidal Coulomb failure stress.For Coulomb failure stress calculation,we used Coulomb 3.40 software.We find that:(1)p-values of tidal stress change suggests a high tidal correlation of earthquake imitations with tidal normal stress change;(2)when tidal normal stress reached the local maximum values of compression and when tidal shear stress were closed to the positive peaks,earthquakes generated more frequently;(3)particular seismogenic environments such as strong continental plate interactions and the existence of fluids or rheologic substance possibly raise the tidal correlations and(4)higher sensitivity of earthquake initiation to earth tide presents along with higher seismicity,suggesting the rate of rain energy accumulation somehow has a dominating effect on the tidal correlation of earthquake initiation.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2009CB421407)the Special Fund for Public Welfare (Meteorology) (Grant No. GYHY200906018)+1 种基金"Strategic Priority Research Program-Climate Change: Carbon Budget and Related Issues" of the Chinese Academy of Sciences (Grant No. XDA05110201)the National Key Technologies R&D Program of China (Grant No. 2007BAC29B03)
文摘Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitation prediction. In one of the experiments, the initial snow conditions over the TP were climatological values; while in the other experiment, the initial snow anomalies were snow depth estimates derived from the passive microwave remote-sensing data. In the current study, the difference between these two experiments was assessed to evaluate the impact of initial snow anomalies over the TP on simulated precipitation. The results indicated that the model simulation for precipitation over eastern China had certain improvements while applying a more realistic initial snow anomaly, especially for spring precipitation over Northeast China and North China and for summer precipitation over North China and Southeast China. The results suggest that seasonal prediction could be enhanced by using more realistic initial snow conditions over TP, and microwave remote-sensing snow data could be used to initialize climate models and improve the simulation of eastern China precipitation during spring and summer. Further analyses showed that higher snow anomalies over TP cooled the surface, resulting in lower near- surface air temperature over the TP in spring and summer. The surface cooling over TP weakened the Asian summer monsoon and brought more precipitation in South China in spring and more precipitation to Southeast China during summer.
基金supported in part by the national basic research program of China 973 program(NO.2012CB518200-G)Army major issue of comprehensive medical security research of flight crew in the plateau(N0.AKJ11J005)
文摘We designed two types of pre-adaption plans for this study. One was a pre-adaption training with progressive intermittent hypoxia, with a constant lower pressure oxygen tank used in the plain before arriving at the plateau （PG）. The other was by progressively increasing the time of exposure to hypoxia with oxygen supplied in stages after radical plateau （RG）. By testing the blood oxygen saturation （SpO2）, heart rate （HR）, and quality of sleep after arriving at the 3800 m high plateau, results showed that the pre-acclimatization and radical groups performed better than the control group （CG）. Both strategies were equivalent in terms of effects and principles in providing more flexible choices for acclimatization.
基金supported by the National Natural Science Foundation of China(grant No.41571013)Project of China Geological Survey(grant No.12120114002101)
文摘Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.
基金This work was supported by the National Program on Global Change and Air-Sea Interaction(grant No.GASI-GEOGE-05-02)the National Natural Science Foundation of China(grant Nos.91955204,42074047 and 92058210)+1 种基金the second Tibetan Plateau Scientific Expedition and Research Program(grant No.2019QZKK2704)Opening Fund of Geomathematics Key Laboratory of Sichuan Province(grant No.scsxdz2020yb03).
文摘To investigate the tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its surrounding areas,we selected over 1,500 focal mechanism solutions of inland earthquakes(epicenter locates at least 100 km to the coastlines)from Global Centroid Moment Tensor(GCMT)project and analyzed the values of tidal normal and shear stress as well as tidal Coulomb failure stress.For Coulomb failure stress calculation,we used Coulomb 3.40 software.We find that:(1)p-values of tidal stress change suggests a high tidal correlation of earthquake imitations with tidal normal stress change;(2)when tidal normal stress reached the local maximum values of compression and when tidal shear stress were closed to the positive peaks,earthquakes generated more frequently;(3)particular seismogenic environments such as strong continental plate interactions and the existence of fluids or rheologic substance possibly raise the tidal correlations and(4)higher sensitivity of earthquake initiation to earth tide presents along with higher seismicity,suggesting the rate of rain energy accumulation somehow has a dominating effect on the tidal correlation of earthquake initiation.
