1. question 1
height of the 1000 hPa surface
pressure (Pa) at sea level

2. height A B high low 850 855 𝑑𝑝 𝑑𝑧 = −𝜌𝑔
start with pressure at 1500 m MSL
then use hydrostatic balance to estimate the height of the 855 mb surface at B
then draw the 855 mb isobar
use the same method to estimate the height of the 850 mb surface at A
and to draw the 850 mb isobar
Note: density variations are secondary – to a first order, density (thickness) can be assumed constant.
height
855
850
high
low A B
𝑑𝑝 𝑑𝑧 = −𝜌𝑔
Pressure decreases with height at about 10 mb every 100 m

3. question 2
DZ1000,500
Z500
Jan 2010
Jan 2010
DZ1000,500
Z500
Jul 2010
Jul 2010

4. question 3
sea-level pressure
Jan 2010
Jul 2010 NH
winter summer SH

5. Schematic zonal-mean cross section (after Palmen & Newton)
 ITCZ

6. The Palmen-Newton model has three meridional circulation cells in each hemisphere
Note that the three-cell pattern ignores seasonal variation and land-sea contrast.

7. How strong are the meridional cells? (zonal mean)
Jan
NH winter
Hadley
Ferrel
note the broad belt of subsidence (12-52ºN) in winter and the broad belt of ITCZ ascent (0-30ºN) in summer.
ITCZ
In the NH winter, over continents, the northern Hadley cell rising branch crosses the Equator into the SH ITCZ,
and its sinking branch extends between 12-50ºN
July
Ferrel
NH summer NH
Hadley SH
Hadley
Effectively ascent dominates in the summer hemisphere, and sinking in the winter hemisphere, and the Hadley cell that straddles the equator is the strongest.
ITCZ

8. Structure of SLP, winds, temperature seasonal march of sea level pressure and sfc winds
northern oceans:
polar lows: Aleutian, Icelandic
subtropical highs: Pacific, Bermuda
northern continents:
- winter highs: Siberian, Intramtn
- summer lows: Pakistan, Sonoran
southern oceans:
- circumpolar (southern) low
- subtropical highs (3 oceans)
observations:
- A see-saw SLP variation dominates over the northern continents, with highs in winter and lows in summer. The seasonal variation of the polar lows and subtropical highs over the northern oceans is also large, and is in opposition to SLP variations over land at corresponding latitudes.
- The southern hemisphere is far more zonally symmetric.
- Note the extremely low SLP around the Antarctic ice dome.

9. seasonal march of surface air temperature
note that the amplitude of the annual temperature range is higher at:
- higher latitudes
- over land rather than over water [this does NOT occur in terms of net radiation Rn]
- over large land masses, especially their eastern side

10. question 4
Speed for 1 = 4.1 m/s
Speed for 2 = 16.4 m/s
Speed for 3 = 10.8 m/s