09.04.2013 Views

Observations and Modelling of Fronts and Frontogenesis

Observations and Modelling of Fronts and Frontogenesis

Observations and Modelling of Fronts and Frontogenesis

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

In a manner exactly analogous to that leading to (16), making<br />

careful use <strong>of</strong> (A6), an equation for the ageostrophic<br />

velocities may be obtained:<br />

g(p<strong>of</strong>Y1(p3 pB)[(h3v3) vBh3TjI + (f u3y)(vB - v3)<br />

g(p0f)[(p3 PB) We] y<br />

This may be rewritten as<br />

re(z) [ Q + (PB p)w(z)Jy)<br />

g(pf)((p3 PB)(h3v3)yy + [(P3 PB)e]y<br />

g(pfY1-(p3 pB)vBh3 (f U3y)(V - v3)<br />

- (poh1)(rX(z) Te(z)<br />

(A9)<br />

[- Q + (PB - p)w(z)]y). (AlO)<br />

Then (AlO) may be integrated across the interval (y2 6'Y2 +<br />

6), in which the transition layer between the two homogeneous<br />

parts <strong>of</strong> the composite layer meet the surface <strong>of</strong> layer 3, <strong>and</strong><br />

the width 26 <strong>of</strong> this region allowed to approach zero. If we<br />

assume that h3 is twice differentiable at y2(t), none <strong>of</strong> the<br />

terms on the right h<strong>and</strong> side <strong>of</strong> (AlO) will be singular in the<br />

limit as 5 0, so their integral across this region will<br />

vanish in that limit. Since layer 1 consists primarily <strong>of</strong><br />

fluid that has been entrained from layer 2, the variation in<br />

PB is very small. If it is neglected altogether, the left<br />

h<strong>and</strong> side <strong>of</strong> (AlO) may be integrated exactly across the<br />

transition region. The result is (23c).

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!