What is Frontal surface; stationary front; occluded front?

Example 22.3 (A typical slope)

At $45{}^{\circ}$ N, $f = 1.03 \times 10^{-4}\,\mathrm{s}^{-1}$. Across a front with $\bar T = 280\,\mathrm{K}$, a temperature contrast of $5\,\mathrm{K}$ and a wind that changes by $10\,\mathrm{m}/\mathrm{s}$ along it, $\tan\alpha = 1.03 \times 10^{-4} \times 280 \times 10/(9.81 \times 5) = 0.0059$, about 1 in 170: the frontal surface reaches a height of $1\,\mathrm{km}$ some $170\,\mathrm{km}$ from the front on the ground. A sharper wind shift gives a steeper surface; a stronger temperature contrast, a gentler one.