The response of tropospheric circulation to perturbations in lower-stratospheric temperature

A multiple regression analysis of the NCEP-NCAR reanalysis dataset shows a response to increased solar activity of a weakening and poleward shift of the subtropical jets. This signal is separable from other influences, such as those of El Nino-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), and is very similar to that seen in previous studies using global circulation models (GCMs) of the effects of an increase in solar spectral irradiance. The response to increased stratospheric (volcanic) aerosol is found in the data to be a weakening and equatorward shift of the jets. The GCM studies of the solar influence also showed an impact on tropospheric mean meridional circulation with a weakening and expansion of the tropical Hadley cells and a poleward shift of the Ferrel cells. To understand the mechanisms whereby the changes in solar irradiance affect tropospheric winds and circulation, experiments have been carried out with a simplified global circulation model. The results show that generic heating of the lower stratosphere tends to weaken the subtropical jets and the tropospheric mean meridional circulations. The positions of the jets, and the extent of the Hadley cells, respond to the distribution of the stratospheric heating, with low-latitude heating forcing them to move poleward, and high-latitude or latitudinally uniform heating forcing them equatorward. The patterns of response are similar to those that are found to be a result of the solar or volcanic influences, respectively, in the data analysis. This demonstrates that perturbations to the heat balance of the lower stratosphere, such as those brought about by solar or volcanic activity, can produce changes in the mean tropospheric circulation, even without any direct forcing below the tropopause.

Look up, look around: is there anything different about team-level OCB in China?

Ethical leadership has been widely identified as the key variable in enhancing team-level organizational citizenship behavior (team-level OCB) in western economic and business contexts. This is challenged by empirical evidence in China and findings of this study. Our study examined the relationship between ethical leadership, organizational ethical context (ethical culture and corporate ethical values) and team-level OCB. Team-level data has been collected from 57 functional teams in 57 firms operating in China. The findings suggest that although ethical leadership is positively associated with team-level OCB, ethical context positively moderates the relationship between ethical leadership and team-level OCB. The higher ethical context is found to be, the greater is the (positive) effects of ethical leadership on team-level OCB and the opposite holds true when ethical context is low. Key implications are discussed on the role of contextual ethics for team level OCB, while managerial implications include how non-Chinese firms could improve team-level OCB in the Chinese business context.