Product Manual

The values for DD
2
are always negative and are derived from the following formula:
TS_106
ΔD
2
= -
H
R
· 10
6
DD
2
Reduction to mean sea level [ppm]
H Height of EDM above sea level [m]
R
6.378 * 10
6
m
Atmospheric corrections in ppm with temperature [°C], air pressure [mb] and height [m] at 60%
relative humidity.
TS_108
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
50°C50°C
40°C40°C
30°C30°C
20°C20°C
10°C10°C
0°C 0°C
-10°C-10°C
-20°C-20°C
550 mb
5000 m 4500
600 650 700 750 800 850 900 950 1000 1050 mb
550 mb 600 650 700 750 800 850 900 950 1000 1050 mb
4000 3500 3000 2500 2000 1500 1000 500 0 m
Atmospheric corrections in ppm with temperature [°F], air pressure [inch Hg] and height [ft] at
60% relative humidity.
TS_109
130°F
120°F
110°F
100°F
90°F
80°F
70°F
60°F
50°F
40°F
30°F
20°F
10°F
0°F
-10°F
-20°F
130°F
120°F
110°F
100°F
90°F
80°F
70°F
60°F
50°F
40°F
30°F
20°F
10°F
0°F
-10°F
-20°F
16
[ ft ]
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 inch Hg
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 inch Hg
16000 15000 14000 13000 12000
11000
10000
9000 8000 7000 6000 5000 4000 3000 2000 1000
o ft
-15
-20
-25
-30
-35
-40
-45
-50
-55
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
Reduction to mean sea
level DD
2
Atmospheric corrections
°C
Atmospheric corrections
°F
Technical Data 63