Workshop Presentations - The Effects of Solar Variability on Earth's Climate - page 22

FIGURE 2.7 Northern hemisphere zonal and annual mean zonal wind (m/s) as a function of latitude and
atmospheric pressure. Top row, right: climatology from National Centers for Environmental Prediction (NCEP)
Reanalysis data set; left: climatology from a simplified climate model. Bottom row, right: solar 11-year-cycle signal
from a multiple regression analysis of NCEP data; left: response in a simple model to heating applied (only) in the
tropical lower stratosphere. Both sets of panels show a weakening and poleward shift in the westerly jet. This
figure does not present a model simulation of solar effects but demonstrates that a thermal perturbation to the
stratosphere can produce similar patterns in tropospheric response, giving indications as to potential mechanisms for
a solar influence on climate. SOURCE: J. Haigh, M. Blackburn, and R. Day, The response of tropospheric
circulation to perturbations in lower-stratospheric temperature, Journal of Climate 18:3672-3685, 2005; ©
Copyright 2005 American Meterological Society (AMS).