Vertical profiling of atmospheric refractivity from ground-based GPS

LOWRY ET AL.: REFRACTIVITY PROFILING FROM GROUND-BASED GPS
6
6
Pt Loma radiosonde (1524 UTC)
Pt Loma radiosonde (2144 UTC)
Pt. Loma GPS (Best-fit model)
Pt. Loma GPS (Best-fit model)
5
SV 01 (1605 d292 99, az 226˚, el 0.9˚)
5
SV 10 (2200 d361 99, az 252˚, el 1.2˚)
Pt. Loma GPS (10 cm RMS envelope)
Pt. Loma GPS (10 cm RMS envelope)
4
4
Altitude (km)
3
Altitude (km)
3
2
2
1
1
A. B.
0
150 175 200 225 250 275 300 325 350
Refractivity (N-units)
0
150 175 200 225 250 275 300 325 350
Refractivity (N-units)
6
6
Pt Loma radiosonde (1657 UTC)
Pt Loma radiosonde (1703 UTC)
Pt. Loma GPS (Best-fit model)
Pt. Loma GPS (Best-fit model)
5
SV 27 (1633 d363 99, az 244˚, el 1.3˚)
5
SV 07 (1727 d034 00, az 196˚, el 1.4˚)
Pt. Loma GPS (10 cm RMS envelope)
Pt. Loma GPS (10 cm RMS envelope)
4
4
Altitude (km)
3
Altitude (km)
3
2
2
1
0
C. D.
150 175 200 225 250 275 300 325 350
Refractivity (N-units)
1
0
150 175 200 225 250 275 300 325 350
Refractivity (N-units)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
Minimum RMS error in GPS Excess Phase (m)
Figure 6. Refractivity versus altitude for the four radiosondes released from the instrument pier at
Point Loma (Figures 6a–6d). White circles are radiosonde measurements, solid black lines are the
best fit model of contemporaneous DS GPS , dashed black lines are the envelope of models with less
than 10 cm RMS error in DS GPS , and color denotes the minimum error in all models of DS GPS at
given (N, Z).
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