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N.H. Schade et al.: Regional Evaluation of ERA-40 Reanalysis Data
Meteorol. Z. 22, 2013
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1961-2000
Box2, 1961-2000
DJF, 1961-2000
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Grid boxes
Box2, DJF, 1961-2000
0 1 2 3 4 5
Sub grid boxes of box 2
Figure 3: Box plots of 2 m air temperatures from measurements (black) and ERA-40 (grey) for the period 1961-2000. Above left: Annual
values, above right: Whiter month DJF for Box 1 and 2. Median values and the 25 and 75 percentiles are marked by the box, the whiskers
show the 10 and 90 percentiles, the plus the percentiles 1, 5, 95 and 99. Below: Same as above but for the four subgrid boxes of Box 2 (see
Fig. 1). Boxes facing to the open sea have odd, land side boxes even numbers.
Mean Air Temperature, December/August,
1961-2000, Box2
Observations [°C]
Mean Sea Level Pressure, December/August,
1961-2000, Box2
1025
1020
1015
1010
1005
1000
995
.-'Qi *
±.'<T
6
☆ .
4M
w ^ ☆ December
☆ 0 August
(tJ&f*
> tr
V*'
/ir
995 1000 1005 1010 1015 1020 1025
Observations [hPa]
Figure 4: Scatter plot of monthly mean 2 m ah temperatures (left) and sea level pressures (right) of measurement and ERA-40 data pahs hi
Box 2 hi December (black stars) and August (grey diamonds). Base period: 1961-2000.
The values of mean SLP in contrast show no systematic
differences between December and August. The
December values differ more from the optimum accordance
line and show a larger spread than the August
values, but are more or less uniformly distributed. The
larger spread in December can be explained by an
increased low pressure activity and pronounced pressure
differences. More low pressure system paths lead through
