Aquarius / SAC-D Science Team MeetingSeattle, WA, USA / 11-14 November 2014
The Aquarius Radiometersand Radio Frequency Interference:
Analysis of RFI at L-Bandand its Impact on Salinity Retrieval
Paolo de Matthaeis, Yan SoldoGESTAR Goddard Space Flight Center, USA
Seung-bum KimJet Propunsion Laboratory, USA
David M. Le VineNASA Goddard Space Flight Center, USA
The Aquarius Radiometers and Radio Frequency Interf
Outline
Introduction
Analysis of RFI environment changes
Conclusions
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 2
Introduction
Undetected RFI is a serious issue because it can
unknowingly cause biases in retriebved salinity
It is usually related to high level RFI but can also
appears without it
Cases of undetected RFI in two different areas of
the world (Japan and North Atlantic) will be
examined here
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 3
SMOS RFI Probability
SMOS detected a large increase of RFI over Japan starting
September 2011
Suspected cause: start of operation in frequency band ad-
jacent (above) to Earth Exploration Satellite Service (EECS)
primary allocation to passive remote sensing systems
40° N
August 25 − September 21, 2011
130° E 135° E 140° E 145° E 30° N
35° N
45° N
SM
OS
RF
I pro
babi
lity
[%]
0
20
40
60
80
100
40° N
September 22 − October 19, 2011
130° E 135° E 140° E 145° E 30° N
35° N
45° N
SM
OS
RF
I pro
babi
lity
[%]
0
20
40
60
80
100
40° N
October 20 − November 16, 2011
130° E 135° E 140° E 145° E 30° N
35° N
45° N
SM
OS
RF
I pro
babi
lity
[%]
0
20
40
60
80
100
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 4
Aquarius RFI and antenna temperature (ascending)
no change in detected RFI...
August 25 − September 21, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
September 22 − October 19, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
October 20 − November 16, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
but large change in observed antenna temperature!
August 25 − September 21, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
September 22 − October 19, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
October 20 − November 16, 2011beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 5
Aquarius RFI and antenna temperature (descending)
same trend is observed in descending tracks(and beams 2,3)
August 25 − September 21, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
September 22 − October 19, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
October 20 − November 16, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
0
20
40
60
80
100
August 25 − September 21, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
September 22 − October 19, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
October 20 − November 16, 2011beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
(TA
V
+T
AH
)/2
(afte
r R
FI f
ilter
ing)
[K
]
180
200
220
240
260
280
300
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 6
Analysis over Kyushu: SMOS RFI
Change is most evident over the island of Kyushu where little
RFI had been detected before September 2011, by either
SMOS or by Aquarius
Kyushu
difference[September 22 − October 19, 2011] − [August 25 − September 21, 2011]
130° E 135° E 140° E 30° N
35° N
40° N
chan
ge in
SM
OS
RF
I pro
babi
lity
[%]
−20
0
20
40
60
80
100
10
15
20
25
30
35
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
SM
OS
RF
I pro
babi
lity
[%]
Kyushu
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 7
Analysis over Kyushu: Aquarius RFI and TA
no recognizable change in Aquarius detected RFI...
0
5
10
15
20
25
30
35
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Kyushu, ascending tracks only
beam 1beam 2beam 3
0
5
10
15
20
25
30
35
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Kyushu, descending tracks only
beam 1beam 2beam 3
but definite change in Aquarius observed antenna temperature compared toexpected antenna temperature
120
140
160
180
200
220
240
260
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Kyushu, ascending tracks only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
120
140
160
180
200
220
240
260
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Kyushu, descending tracks only
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 8
Analysis over Pacific Ocean, Region P
P1
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
P2
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 2, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
P3
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 3, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
P1
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
P2
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 2, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
P3
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 3, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 9
Analysis of Region P: Aquarius Observations
ascending
0
5
10
15
20
25
30
35
40
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
regions P1, P2, P3 / ascending tracks only
beam 1beam 2beam 3
96
98
100
102
104
106
108
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
regions P1, P2, P3 / ascending tracks only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
29
30
31
32
33
34
35
36
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
sea
surf
ace
salin
ity S
SS
[P
SU
]
regions P1, P2, P3 / ascending tracks only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
descending
0
5
10
15
20
25
30
35
40
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
regions P1, P2, P3 / descending tracks only
beam 1beam 2beam 3
96
98
100
102
104
106
108
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
regions P1, P2, P3 / descending tracks only
29
30
31
32
33
34
35
36
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
sea
surf
ace
salin
ity S
SS
[P
SU
]
regions P1, P2, P3 / descending tracks only
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 10
Analysis over Pacific Ocean, Region Q
Q1
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 1, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
Q2
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 2, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
Q3
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 3, ascending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
Q1
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 1, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
Q2
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 2, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
Q3
[September 22 − October 19, 2011] − [August 25 − September 21, 2011]beam 3, descending
130° E 135° E 140° E 145° E 150° E 155° E 25° N
30° N
35° N
40° N
45° N
50° N
chan
ge in
(ob
serv
ed−
expe
cted
) (T
AV
+T
AH
)/2
[K]
−2
−1
0
1
2
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 11
Analysis of Region Q: Aquarius Observations
ascending
0
5
10
15
20
25
30
35
40
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
regions Q1, Q2, Q3 / ascending tracks only
beam 1beam 2beam 3
96
98
100
102
104
106
108
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
regions Q1, Q2, Q3 / ascending tracks only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
32
32.5
33
33.5
34
34.5
35
35.5
36
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
sea
surf
ace
salin
ity S
SS
[P
SU
]
regions Q1, Q2, Q3 / ascending tracks only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
descending
0
5
10
15
20
25
30
35
40
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
regions Q1, Q2, Q3 / descending tracks only
beam 1beam 2beam 3
96
98
100
102
104
106
108
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
regions Q1, Q2, Q3 / descending tracks only
32
32.5
33
33.5
34
34.5
35
35.5
36
25−Aug−2011
03−Sep−2011
13−Sep−2011
22−Sep−2011
02−Oct−2011
11−Oct−2011
21−Oct−2011
30−Oct−2011
09−Nov−2011
18−Nov−2011
28−Nov−2011
07−Dec−2011
17−Dec−2011
26−Dec−2011
05−Jan−2012
sea
surf
ace
salin
ity S
SS
[P
SU
]
regions Q1, Q2, Q3 / descending tracks only
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 12
Discussion
Aquarius RFI filter is missing most of the RFI emittedby wireless telecommunication systems
Quantifying the effect on SSS and soil moistureretrievals is difficult due to the short time range rangeof RFI-free measurements (4 weeks)
Effect is very large over land but present, althoughalmost undetectable, over ocean as well
Further analysis are mostly confined to the areaaround Kyushu due to presence of radar systems RFIon other parts of Japan
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 13
Change in RFI Environment in Canada and North Atlantic
Following requests by SMOS, in November 2013 radars part of the North WarningSystem (formerly DEW Line) adjusted their operating frequency to avoid interferencein the 1400 to 1427 MHZ band
As a result, most antenna sidelobe RFI over the Eastern part of the North Atlanticdisappeared starting on November 26, 2013
An analysis has been performed on selected regions, findings shown here are limitedto three of them
−80 −60 −40 −20 010
20
30
40
50
60
70
80
longitude [deg]
latit
ude
[deg
]
October 2013
A
B
C
perc
enta
ge o
f RF
I [%
]
0
20
40
60
80
100
−80 −60 −40 −20 010
20
30
40
50
60
70
80
longitude [deg]
latit
ude
[deg
]
December 2013
A
B
C
perc
enta
ge o
f RF
I [%
]
0
20
40
60
80
100
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 14
Characteristics of Selected Study Regions
Regions under study partially overlap “RFI exclusion zone” that is not used forcalibration, and include
an area moderately affected by RFI emissions from Canada (region A)
an area severely affected by RFI emissions from Canada (region B)
an area affected by RFI emissions from Europe (region C)
−80 −70 −60 −50 −40 −30 −20 −10 010
20
30
40
50
60
70
80
longitude [deg]
latit
ude
[deg
]
A
B
C
ascending
−80 −70 −60 −50 −40 −30 −20 −10 010
20
30
40
50
60
70
80
longitude [deg]
latit
ude
[deg
]
A
B
C
descending
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 15
North Atlantic Region A
ascending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region A, ascending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region A, ascending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region A, ascending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
descending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region A, descending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region A, descending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region A, descending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 16
North Atlantic Region B
ascending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region B, ascending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region B, ascending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region B, ascending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
descending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region B, descending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region B, descending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region B, descending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 17
North Atlantic Region C
ascending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region C, ascending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region C, ascending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region C, ascending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
descending
0
5
10
15
20
25
30
35
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
perc
enta
ge o
f rad
iom
eter
RF
I−fla
gged
sam
ples
[%]
Atlantic Ocean, region C, descending orbits only
beam 1beam 2beam 3
96
97
98
99
100
101
102
103
104
105
106
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
ante
nna
tem
pera
ture
(T
AV
+T
AH
)/2
[K]
Atlantic Ocean, region C, descending orbits only
beam 1, obsbeam 1, expbeam 2 obsbeam 2, expbeam 3, obsbeam 3, exp
33.5
34
34.5
35
35.5
36
36.5
37
37.5
25−Aug−2011
15−Nov−2011
05−Feb−2012
27−Apr−2012
18−Jul−2012
08−Oct−2012
29−Dec−2012
22−Mar−2013
12−Jun−2013
02−Sep−2013
23−Nov−2013
13−Feb−2014
06−May−2014
27−Jul−2014
18−Oct−2014
sea
surf
ace
salin
ity S
SS
[P
SU
]
Atlantic Ocean, region C, descending orbits only
beam 1, obsbeam 1, ancbeam 2 obsbeam 2, ancbeam 3, obsbeam 3, anc
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 18
Comparison with ARGO SSS
comparison with ARGO data shows a similar trend
33
33.5
34
34.5
35
35.5
36
36.5
37
07−Sep−2011
14−Dec−2011
21−Mar−2012
28−Jun−2012
04−Oct−2012
10−Jan−2013
19−Apr−2013
26−Jul−2013
01−Nov−2013
08−Feb−2014
17−May−2014
24−Aug−2014
sea
surf
ace
salin
ity [
PS
U]
Atlantic Ocean, region A
Aquarius ascAquarius descARGO
33
33.5
34
34.5
35
35.5
36
36.5
37
07−Sep−2011
14−Dec−2011
21−Mar−2012
28−Jun−2012
04−Oct−2012
10−Jan−2013
19−Apr−2013
26−Jul−2013
01−Nov−2013
08−Feb−2014
17−May−2014
24−Aug−2014
sea
surf
ace
salin
ity [
PS
U]
Atlantic Ocean, region B
Aquarius ascAquarius descARGO
33
33.5
34
34.5
35
35.5
36
36.5
37
07−Sep−2011
14−Dec−2011
21−Mar−2012
28−Jun−2012
04−Oct−2012
10−Jan−2013
19−Apr−2013
26−Jul−2013
01−Nov−2013
08−Feb−2014
17−May−2014
24−Aug−2014
sea
surf
ace
salin
ity [
PS
U]
Atlantic Ocean, region C
Aquarius ascAquarius descARGO
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 19
Year-by-Year Comparison with ARGO SSS
ascending
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region A / ascending tracks
2011201220132014
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region B / ascending tracks
2011201220132014
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region C / ascending tracks
2011201220132014
descending
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region A / descending tracks
2011201220132014
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region B / descending tracks
2011201220132014
−2
−1.5
−1
−0.5
0
0.5
1
01−Jan01−Feb
01−Mar01−Apr
01−May01−Jun
01−Jul01−Aug
01−Sep01−Oct
01−Nov01−Dec
31−Dec
diffe
renc
e S
SS
(Aqu
ariu
s) −
SS
S(A
rgo)
[PS
U]
Atlantic Ocean, region C / descending tracks
2011201220132014
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 20
Estimation of SSS Bias Caused by Undetected RFI
region A region B region C
ARGO SSS (2) - ARGO SSS (1) -0.0077 0.0579 -0.0062
asc+desc 0.1043 0.2593 0.0796
AQ SSS (2) - AQ SSS (1) asc 0.0281 0.1763 0.1265
desc 0.1806 0.3423 0.0327
estimated bias asc+desc 0.1120 0.2014 0.0858
in Aquarius SSS asc 0.0358 0.1184 0.1327
caused by undetected RFI? desc 0.1883 0.2844 0.0389
(1) =⇒ average of (23-Nov-2011 to 23-Aug-2012) and (22-Nov-2012 to 24-Aug-2013)
(2) =⇒ (23-Nov-2013 to 24-Aug-2014)
units are PSU
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 21
Conclusions
Aquarius RFI filter is missing some RFI, need to adda way to detect it?
possibility of unexpected undetected RFI must betaken into consideration for calibration
use of SMOS RFI product can help in some analysis
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-Band and its Impact on Salinity Retrieval – p. 22
