The stratosphere as a puppeteer of European winter climate

No abstract

Longitudinal associations between trauma exposure and executive functions in children:Findings from a Dutch birth cohort study

This study is the first to distinguish two possible predictive directions between trauma exposure and executive functioning in children in a community sample. The sample consists of 1006 children from two time points with a seven years’ time interval of a longitudinal Dutch birth cohort study, the ABCD-study (Van Eijsden et al., 2011). We analyzed the longitudinal associations between trauma exposure and executive functioning using structural equation modeling. The results demonstrated that (after controlling for prenatal substance exposure and mothers’ educational level) trauma exposure before age 5 is predictive of poorer executive functioning at age 12 and trauma exposure between age 6 and 12. However, the association between executive functioning at age 5 and trauma exposure between age 6 and 12 was not statistically significant. Our results indicate that early life trauma exposure has a long term impact on later executive functioning and not the other way around. On top of that, trauma exposure seems to accumulate across childhood when children are exposed to a traumatic event before the age of 5. When looking at the potential moderating role of parenting behavior we found no evidence for such a moderating effect of parenting behavior. Our findings showed that children exposed to trauma early in life may experience problems in executive functioning later in life and they seem at higher risk for cumulative trauma exposure. Clinical practice should take this into account in both the way they provide (early) mental health care and in prevention and recognition of early trauma exposure

Analysis of the coupling between the stratospheric meridional wind and the surface level zonal wind during 1979-93 Northern Hemisphere extratropical winters

The coupling between the stratosphere and the troposphere has been investigated by analysing low-frequency variations in: (1) the meridional mass flux into the polar cap (north of 60°N), computed separately for the stratosphere and the troposphere; (2) the polar cap mean surface pressure, and (3) the surface level meridional pressure gradient and zonal wind around 60°N. The analysis has been done for the 1979–93 Northern Hemisphere (NH) winters, using ECMWF reanalysis data. The results show that for all winters the meridional mass flux variations in the stratosphere precede those in the troposphere, by about one day. This result can also be obtained qualitatively with a very simple model, based on the zonally averaged zonal and meridional momentum equations. The lag is not very sensitive to the latitude of the southern boundary of the polar cap. The analysed variations in the polar cap mean surface pressure associated with variations in the meridional mass flux, determine most of the variability in the analysed meridional surface pressure gradient and the associated surface zonal wind around 60°N. The results also show that in the stratosphere the Coriolis force associated with the zonal-mean meridional wind is in near-balance with the convergence of the eddy momentum flux, and in the lower troposphere with the zonal frictional force. In summary, the results indicate that in the extratropical northern winter hemisphere, low-frequency variations in the meridional wind in the stratosphere induce low-frequency variations in the zonal wind near the surface

The stratosphere as a puppeteer of European winter climate

No abstract