Post on 20-Dec-2015
Application of GPS data on Severe Weather Forecasting
To investigate correlation between PWV and VIL, and hence its role in lightning/damaging winds monitoring/nowcasting
Summer Internship at the Hong Kong Observatory 2006
Law Ka Hei (CUHK/PHY/3)
Supervisor: Linus Yeung
Motivation
Project Goal Use PWV for severe weather nowcasting
PWV - Precipitable Water Vapor Represent amount of water vapor in an atmospher
ic column VIL - Vertically Integrated Liquid
Represent amount of liquid water in an atmospheric column
Highly related to rainfall
Calculation of PWV
GPS SignalDelay
IonosphericDelay
TroposphericDelay
HydrostaticDelay
Wet Delay
PWV
Visualization Tool – Web
PWV http://openlab3/~swirls/2005.html
VIL http://openlab3/~swirls/vil.cgi?id=0507201200-hks
l Radar Image
http://openlab3/~swirls/radar_js.html
PWV Climatology
Diurnal PWV Mean in Spring
52.00
53.00
54.00
55.00
56.00
57.00
58.00
59.00
0 5 10 15 20
Hour
PW
V M
ea
n (
mm
) hkfn
hkkt
hklt
hksc
hksl
hkst
MeanDiurnal PWV Mean in Summer
43.00
48.00
53.00
58.00
63.00
0 5 10 15 20
Hour
PW
V M
ean
(mm
) hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Mean in Autumn
42.00
47.00
52.00
57.00
62.00
0 5 10 15 20
Hour
PW
V M
ean
(mm
) hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Mean in Winter
20.00
25.00
30.00
35.00
40.00
0 5 10 15 20
Hour
PW
V M
ean
(mm
) hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Mean in Spring
43.00
48.00
53.00
58.00
63.00
0 5 10 15 20
Hour
PW
V M
ean
(mm
) hkfn
hkkt
hklt
hksc
hksl
hkst
Standard DeviationDiurnal PWV Standard Deviation in Summer
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
15.00
0 5 10 15 20
Hour
PW
V S
D (m
m)
hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Standard Deviation in Winter
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
15.00
0 5 10 15 20
Hour
PW
V S
D (m
m)
hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Standard Deviation in Spring
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
15.00
0 5 10 15 20
Hour
PW
V S
D (m
m)
hkfn
hkkt
hklt
hksc
hksl
hkst
Diurnal PWV Standard Deviation in Autumn
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
15.00
0 5 10 15 20
Hour
PW
V S
D (m
m)
hkfn
hkkt
hklt
hksc
hksl
hkst
PWV before Rainstorm
0
0.5
1
1.5
2
2.5
3
3.5
-10 -8 -6 -4 -2 0
Time Before (Hour)
Ave
rag
e P
WV
Tim
e D
iffe
ren
ce (
mm
)
Scatter Plot: VIL vs PWV
50 52 54 56 58 60 62 64 66 68 70 72 74 76 78
PWV
-2
0
2
4
6
8
10
12
14
16
18
7km V
IL
VIL vs PWV Time Change
-6 -4 -2 0 2 4 6
PWV Time Difference (-2, -6) Anomaly
-2
0
2
4
6
8
10
12
14
16
18
7km V
IL
VIL vs PWV Time Change
-5 -4 -3 -2 -1 0 1 2 3 4 5 6
PWV Time Difference (-8, -15) Anomaly
-2
0
2
4
6
8
10
12
14
16
18
7km V
IL