Rain Rates Measured Acoustically Using Passive
Aquatic Listener
Jie Yang, William E. Asher, Jeffrey A. Nystuen, and Andrew T. Jessup
Applied Physics Laboratory, University of Washington
Acoustics Department talk, April 7, 2014
Argo floats (collaboration with Steve Riser)
• Park depth – 1000 m• Profile duration – several days• Expected lifetime – s e v e ra l
ye a r s• Iridium communication – 2-way
PAL for moorings
• Adaptive underwater recorder• Very low power consumption• High bandwidth (1-40 kHz)• Park depth – 2000 m
330 40 50 60 7020
25
30
35
40
45
50
55
SPL at 5 kHz
SP
L a
t 2
0 k
Hz
Float 6917, results using find acf OSP2, JD:112-476
Winddrizzlerainrain windshippingdcalm
0 10 20 30 400
500
1000
1500
2000
2500
3000
3500
4000
Rainfall Rate (mm/hr)H
isto
gra
m
Float 6917
100 150 200 250 300 350 400 450 5000
5
10
15
20
25
30
35
Ra
infa
ll ra
te (
mm
/hr)
Float 6917
100 150 200 250 300 350 400 450 5000
200
400
600
800
1000
1200
1400
Ra
infa
ll a
ccu
mul
atio
n (
mm
)
Time (JD, 2011)
2 4 6 8 10 12 140
500
1000
1500
2000
Wind speed (m/s)
His
tog
ram
Float 6917
TropicalPacific Float #6917
4/2011 – 3/2012
Comparison of wind speed between PAL and central mooring
Oct Nov Dec Jan 13 Feb Mar Apr May0
2
4
6
8
10
12
14
Date
Win
d sp
eed
(m
s)
central mooringFloat 7587
Float 7587
Comparison of
accumulated rain amount
Sep12 Oct Nov Dec Jan13 Feb Mar Apr May Jun Jul Aug0
100
200
300
400
500
600
700
Date
Acc
umul
ate
d ra
in (
mm
)
Central mooringTRMMFloat6923Float7681Float7587
Float 6923
Float 7681
Float 7587
• Passive acoustic monitoring of the ocean can provide measurements of wind speed and rainfall rate
• Passive acoustic monitoring technology has been deployed on STS/PAL floats
• Initial results from five STS/PAL floats (SPURS region, Equatorial Pacific, and Bay of Bengal) show wind speed and rainfall climatology
• Acoustically derived wind speed compares very well with central mooring MET data
• Comparison between acoustically derived rainfall accumulation using the twelve SPURS STS/PAL floats with satellite data is very encouraging
Summary