Land surface heating of the Tibetan Plateau (TP) plays an important role in the Asian Monsoon system. In this study, the interannual variability of the sensible heat flux over the TP and its connection with the summer...Land surface heating of the Tibetan Plateau (TP) plays an important role in the Asian Monsoon system. In this study, the interannual variability of the sensible heat flux over the TP and its connection with the summer monsoon intensity and onset date was examined based on the newly released land "reanalysis" data, produced by NASA Global Land Data Assimilation System. Although correlation analyses don't show a significant relevance to the summer monsoon intensity, the interannual anomalies in sensible heating near the south flank of the TP indicate a weak reversal in the relationship with the onset date of the West Pacific East Asian monsoon. A diagnostic study shows that above (below) normal sensible heating over the south flake of the TP will lead to rapid (slow) warming of the upper air column over the TP and early (later) reversal of (overturn) the meridional temperature gradient and the vertical wind shear. This will further lead to an earlier (later) onset of the Asian Monsoon.展开更多
Studies of metabolic variation in birds have involved both wild and captive individuals, but few studies have investi- gated whether captivity directly influences metabolic rates, despite such variation potentially co...Studies of metabolic variation in birds have involved both wild and captive individuals, but few studies have investi- gated whether captivity directly influences metabolic rates, despite such variation potentially confounding conclusions regarding how metabolic rates respond to the conditions under study. In addition, whether short-term captivity influences metabolic rate re- peatability in birds is currently uninvestigated. In this study, we measured Msum （maximal cold-induced metabolic rates） in sum- mer acclimatized American goldfinches Spinus tristis directly after capture from wild populations, after approximately 2 weeks of indoor captivity （Captive 1）, and again after an additional 1-2 weeks of captivity （Captive 2）. M~ increased significantly （16.9%） following the initial captive period, but remained stable thereafter. Body mass （Mb） also increased significantly （9.2%） during the initial captive period but remained stable thereafter, suggesting that muscle growth and/or remodeling of body composition pro- duced the observed metabolic variation. Mb and Msum were not significantly repeatable between wild and Captive 1 birds, but were significantly repeatable between Captive 1 and Captive 2 groups. These data suggest that caution must be exercised when extrapolating metabolic rates from short-term captive to wild populations. In addition, Msum was a repeatable trait for birds under conditions where mean metabolic rates remained stable, but Msum repeatability disappeared during acclimation to conditions pro- moting phenotypically flexible metabolic responses. This suggests that the capacity for phenotypic flexibility varies among indi- viduals, and such variation could have fitness consequences展开更多
基金partially supported by the National Public Benefit Research Foundation (No.GYHY200906018)an open project of the Institute of Plateau Meteorology
文摘Land surface heating of the Tibetan Plateau (TP) plays an important role in the Asian Monsoon system. In this study, the interannual variability of the sensible heat flux over the TP and its connection with the summer monsoon intensity and onset date was examined based on the newly released land "reanalysis" data, produced by NASA Global Land Data Assimilation System. Although correlation analyses don't show a significant relevance to the summer monsoon intensity, the interannual anomalies in sensible heating near the south flank of the TP indicate a weak reversal in the relationship with the onset date of the West Pacific East Asian monsoon. A diagnostic study shows that above (below) normal sensible heating over the south flake of the TP will lead to rapid (slow) warming of the upper air column over the TP and early (later) reversal of (overturn) the meridional temperature gradient and the vertical wind shear. This will further lead to an earlier (later) onset of the Asian Monsoon.
文摘Studies of metabolic variation in birds have involved both wild and captive individuals, but few studies have investi- gated whether captivity directly influences metabolic rates, despite such variation potentially confounding conclusions regarding how metabolic rates respond to the conditions under study. In addition, whether short-term captivity influences metabolic rate re- peatability in birds is currently uninvestigated. In this study, we measured Msum （maximal cold-induced metabolic rates） in sum- mer acclimatized American goldfinches Spinus tristis directly after capture from wild populations, after approximately 2 weeks of indoor captivity （Captive 1）, and again after an additional 1-2 weeks of captivity （Captive 2）. M~ increased significantly （16.9%） following the initial captive period, but remained stable thereafter. Body mass （Mb） also increased significantly （9.2%） during the initial captive period but remained stable thereafter, suggesting that muscle growth and/or remodeling of body composition pro- duced the observed metabolic variation. Mb and Msum were not significantly repeatable between wild and Captive 1 birds, but were significantly repeatable between Captive 1 and Captive 2 groups. These data suggest that caution must be exercised when extrapolating metabolic rates from short-term captive to wild populations. In addition, Msum was a repeatable trait for birds under conditions where mean metabolic rates remained stable, but Msum repeatability disappeared during acclimation to conditions pro- moting phenotypically flexible metabolic responses. This suggests that the capacity for phenotypic flexibility varies among indi- viduals, and such variation could have fitness consequences
