Quantifying Observation Impact for a Limited Area Atmospheric Forecast Model - Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications - page 135

b

60N

Radiosondes

1.4
1
0.7
0.5
0.3
0.2
− 0.2
−

a

50N

40N

0.3
− 0.5
− 0.7

−

30N

1
− 1.4
− 1.8

− 2.2
−

20N

2.6
− 3

10N

130w 120w 110w 100w 90w 80w 70w 60w

d

60N

Radiosondes

1.4
1
0.7
0.5
0.3
0.2
− 0.2
−

c

50N

40N

0.3
− 0.5
− 0.7

− 1

30N

− 1.4

− 1.8
−

20N

2.2
− 2.6
−

3

10N

170w 160w 150w 140w 130w 120w 110w 100w

f

60N

Radiosondes

e

1.4
1
0.7
0.5
0.3
0.2
− 0.2
−

50N

40N

0.3
− 0.5
− 0.7

− 1

30N

1.4

−

− 1.8

− 2.2
−

20N

2.6
− 3

10N
20E

30E 40E 50E 60E 70E 80E 90E

Fig. 6.4 Averaged observation impacts by type for each forecast cycle ( left ) and contribution at
radiosonde locations ( right , multiplied by 1,000) for domains covering ( a )and( b ) the continental
United States, ( c )and( d ) the eastern Pacific Ocean and western United States, and ( e )and( f )
southwest Asia. The impacts were calculated for 12 h forecasts valid over the period 0000 UTC
24-0000 UTC 31 Dec 2010. Values are in units of J kg 1