Homogenization (instrumental correction) of water vapour data from Vaisala radiosondes and older...
18
Homogenization (instrumental correction) of water vapour data from Vaisala radiosondes and older (MARZ, RKZ) used in Polish aerological service Barbara Brzóska
-
Upload
madalynn-holeman -
Category
Documents
-
view
216 -
download
2
Transcript of Homogenization (instrumental correction) of water vapour data from Vaisala radiosondes and older...
Homogenization(instrumental correction)
of water vapour data from Vaisala
radiosondes and older (MARZ, RKZ) used in
Polish aerological serviceBarbara Brzóska
GoalThe water vapour content in the atmosphere has crucial role for the ozone chemistry and photochemical processes of its destruction. Thus the research on its variability are of crucial importance, particularly in the levels of upper troposphere and lower stratosphere (UTLS). The most reliable source of information on the relative humidity (RH) are the radiosonde measurements. Unfortunately, the numerous changes of radiosonde types influence the homogeneity of the RH series. The simple humidity sensors (MARZ, RKZ) was used in Polish aerological service till the 90-ties. Since 1992 Vaisala radiondes are used. However, the change of the radiosonde type in June 1999 (RS-80A to RS-90) and in June 2006 (RS-90 to RS-92) caused the break of homogeneity of the series.
1970 1975 1980 1985 1990 1995 2000 2005 201025
30
35
40
45
50
55
60
65
70Legionowo 400 hPa
time [years]
RH
[%]
Smoothing
1992 1994 1996 1998 2000 2002 2004 2006 200850
55
60
65
70
75
80
85
90
95
trend y=0.82*x-1559
trend y=-0.05*x+175
Legionowo 1000 hPa
time [years]
RH
[%
]
1992 1994 1996 1998 2000 2002 2004 2006 200850
55
60
65
70
75
80
85
90
95
trend y=0.94*x-1798 trend y=0.08*x-79
Legionowo 1000 hPa
time [years]
RH
[%
]
In the first step of homogenisation, data from Vaisala radiosondes was smoothed using a 12-month moving average.
1992 1994 1996 1998 2000 2002 2004 2006 20080
5
10
15
20
25
30
35
40
trend y=-0.04*x+92
trend y=0.24*x-462
Legionowo 200 hPa
time [years]
RH
[%
]
1992 1994 1996 1998 2000 2002 2004 2006 20080
5
10
15
20
25
30
35
40
trend y=-0.25*x+507
trend y=0.15*x-284
Legionowo 200 hPa
time [years]
RH
[%
]
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
Humidity correction methods for RS-80A radiosonde 1
• Laboratory measurements conducted at Vaisala; the magnitude of the correction factor is about 1.1 at –35°C, 1.4 at –50°C, 1.8 at –60°C, and 2.5 at –70°C. SPARC Assessment of Upper Tropospheric and Stratospheric Water Vapour, 2000:
Hcorr = (-2∙10-5∙t3 - 0.0021∙t2 - 0.089∙t - 0.3) ∙H
(‘Vaisala’)
Humidity correction methods for RS-80A radiosonde 2
• Simultaneous RH measurements from RS80-A and frostpoint hygrometers at NOAA, Boulder (cooperation with Vaisala):
Miloshevich, L. M. et al., 2000: “Characterization and correction of relative humidity measurements from Vaisala RS80-A radiosondes at cold temperatures”:
Hcorr =H * G(t) (‘Miloshevich’)
G(t) = (3.9407∙10-8) ∙t4 + (1.8179∙10-6) ∙t3 + (1.5783∙10-4) ∙t2 + (-5.9662∙10-3) ∙t + 0.9278
Humidity correction methods for RS-80A radiosonde 3
• Data collected during TOGA COARE experiment (1992/1993); the temperature dependence error for the RS-80A results from an approximation of a linear function of temperature to the actual nonlinear temperature dependence of the sensor, and also introduces a dry bias.Wang et al., 2002: “Corrections of humidity measurement errors from the Vaisala RS80 radiosonde - Application to TOGA COARE Data”
(‘Wang’)
Humidity correction methods for RS-80A radiosonde 4
• A new measuring and evaluation method has been developed at the Meteorological Observatory Lindenberg by Leiterer; Research reference humidity radiosondes are the experimental basis using the new measuring and evaluation method of so-called "standardised frequencies„:
Leiterer, U., et al.,2002:"Method for correction of RS80 A – Humicap
humidity profiles”
])404.0*112.0*005.0()%100,(
)%100
*%6.5([*]404.0*112.0*005.0[
]%100
*%6.5[
22
tticetH
HH
tt
HHHcorr
w
%100)(
)()%100,(
Te
TeicetH
w
iw
• ei(T) saturation vapour pressure with respect to ice in hPa • ew(T) saturation vapour pressure with respect to water in hPa
• ln ei(T) =(-6024.5282)*T-1+24.7219+(1.0613868*10-2)*T+
+(-1.3198825*10-5)*T2+(-0.49382577)*lnT
• ln ew(T) =(-6096.9385)*T-1+16.635794+(-2.711193*10-2)*T+
+(1.673952*105)*T2 +2.433502*lnT
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity uncorrected
time [years]
pres
sure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity corrected Wang
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity corrected Leiterer
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity corrected Miloshevich
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity corrected Vaisala
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Leba humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity uncorrected
time [years]
pres
sure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity corrected Vaisala
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity corrected Wang
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity corrected Leiterer
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity corrected Miloshevich
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1994 1996 1998 2000 2002 2004 2006 2008
200
250
300
400
500
700
850925
1000
Legionowo humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity uncorrected
time [years]
pres
sure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity corrected Vaisala
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity corrected Wang
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity corrected Leiterer
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity corrected Miloshevich
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1993 1995 1997 1999 2001 2003 2005 2007
200
250
300
400
500
700
850925
1000
Wroclaw humidity uncorrected
time [years]
pre
ssure
[hP
a]
RS-80A RS-90,92
0
10
20
30
40
50
60
70
80
90
100
1992 1994 1996 1998 2000 2002 2004 2006 200835
40
45
50
55
60
65
trend uncorrected y=0.27*x-490
trend corrected Wang y=0.26*x-464
trend corrected Leiterer y=0.21*x-376
Leba 700 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200835
40
45
50
55
60
65
trend uncorrected y=-0.07*x+200
trend corrected Wang y=-0.08*x+219
trend corrected Leiterer y=-0.12*x+293
Legionowo 700 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200835
40
45
50
55
60
65
trend uncorrected y=-0.005*x+67
trend corrected Wang y=-0.01*x+79
trend corrected Leiterer y=-0.05*x+165
Wroclaw 700 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200825
30
35
40
45
50
55
trend uncorrected y=-0.004*x+53
trend corrected Wang y=-0.29*x+633
trend corrected Leiterer y=-0.26*x+560
Wroclaw 500 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200825
30
35
40
45
50
55
trend uncorrected y=-0.04*x+130
trend corrected Wang y=-0.34*x+732
trend corrected Leiterer y=-0.30*x+651
Legionowo 500 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200825
30
35
40
45
50
55
trend uncorrected y=0.21*x-381
trend corrected Wang y=-0.10*x+235
trend corrected Leiterer y=-0.03*x+109
Leba 500 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200820
22
24
26
28
30
32
34
36
38
40
trend uncorrected y=0.73*x-1422
trend corrected Wang y=-0.09*x+221
trend corrected Leiterer y=0.06*x-96
Wroclaw 250 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200820
25
30
35
40
trend uncorrected y=0.80*x-1572
trend corrected Wang y=-0.03*x+88
trend corrected Leiterer y=0.12*x-200
Legionowo 250 hPa
time [years]
RH
[%]
1992 1994 1996 1998 2000 2002 2004 2006 200820
25
30
35
40
trend uncorrected y=0.80*x-1579
trend corrected Wang y=0.02*x+3 trend corrected Leiterer y=0.18*x-336
Leba 250 hPa
time [years]
RH
[%]
Humidity correction methods for soviet (MARZ, RKZ) radiosondes
• Due to good quality of corrective method processed by dr Leiterer’s group (Lindenberg, Germany) for measurements executed with radiosounds RS-80A, for correction of data from soviet radiosondes MARZ and RKZ, the corrective method processed also by Leiterer’s group have been used. This method bases on comparison of humidity data from radiosounding and satellite measurements.
1973 1977 1981 1985 1989 1993 1997 2001 2005
400
500
700
850
925
1000
Leba humidity corrected
time [years]
pre
ssure
[hP
a]
MARZ, RKZ Vaisala
30
40
50
60
70
80
90
100
1973 1977 1981 1985 1989 1993 1997 2001 2005
400
500
700
850
925
1000
Leba humidity uncorrected
time [years]
pre
ssure
[hP
a]
MARZ, RKZ Vaisala
30
40
50
60
70
80
90
100
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007
400
500
700
850
925
1000
Legionowo humidity corrected
time [years]
pre
ssure
[hP
a]
MARZ, RKZ Vaisala
30
40
50
60
70
80
90
100
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007
400
500
700
850
925
1000
Legionowo humidity uncorrected
time [years]
pre
ssure
[hP
a]
MARZ, RKZ Vaisala
30
40
50
60
70
80
90
100
1991 1994 1998 2002 2006
400
500
700
850
925
1000
Wroclaw humidity corrected
time [years]
pre
ssure
[hP
a]
MARZ,RKZ Vaisala
30
40
50
60
70
80
90
100
1991 1994 1998 2002 2006
400
500
700
850
925
1000
Wroclaw humidity uncorrected
time [years]
pre
ssure
[hP
a]
MARZ,RKZ Vaisala
30
40
50
60
70
80
90
100
1970 1975 1980 1985 1990 1995 2000 2005 201035
40
45
50
55
60
65
70
75
trend uncorrected y=-0.41*x+874
trend corrected y=0.03*x+1
Leba 700 hPa
time [years]
RH
[%
]
1970 1975 1980 1985 1990 1995 2000 2005 201035
40
45
50
55
60
65
70
75
trend uncorrected y=-0.39*x+841
trend corrected y=-0.04*x+140
Legionowo 700 hPa
time [years]
RH
[%
]
1970 1975 1980 1985 1990 1995 2000 2005 201025
30
35
40
45
50
55
60
65
70
trend uncorrected y=-0.57*x+1191
trend corrected y=-0.07*x+175
Legionowo 400 hPa
time [years]
RH
[%
]
1970 1975 1980 1985 1990 1995 2000 2005 201025
30
35
40
45
50
55
60
65
70
trend uncorrected y=-0.57*x+1174
trend corrected y=0.045*x-48
Leba 400 hPa
time [years]
RH
[%
]
Conclusion 1
For homogenisation of humidity data from Vaisala radiosondes (RS-80A, RS-90 and RS-92) four correction methods have been chosen for correction data from RS-80A radiosounds. Two methods (‘Wang’ and ‘Leiterer’) were submitted for further studies. Analyses of humidity trends on different goepotential surfaces show dominance of ‘Leirerer’ correction over ‘Wang’ one.
BUT
• At the first view, the corrections shift only the humidity values to bigger ones. The question is if it is enough, even as the first step of correction?
• Another question is, what is the reason for the humidity sensors behavior: greater RS-90’s sensitivity and/or sensor
heating mechanism?
• It is still unclear, what are the ‘reliable’ humidity tendencies in the stratosphere?
1992 1994 1996 1998 2000 2002 2004 2006 20080
5
10
15
20
25
30
35
40
trend y=-0.25*x+507
trend y=0.15*x-284
Legionowo 200 hPa
time [years]
RH
[%]
Conclusion 2
For homogenisation of humidity data from soviet (MARZ and RKZ) and finnish (RS-80A, RS-90 and RS-92) radiosondes the correction methods executed by Leiterer’s group have been chosen for correction data from soviet radiosondes.
Adopted method improve quality of data however, there is still not so good so as data after correction can become subject climatic analyses.
![Introduction to upper air measurements with radiosondes and other in situ observing systems [3]](https://static.fdocuments.us/doc/165x107/56814101550346895dacc6cc/introduction-to-upper-air-measurements-with-radiosondes-and-other-in-situ-observing-56918f2ab989f.jpg)
![Introduction to upper air measurements with radiosondes and other in situ observing systems [2]](https://static.fdocuments.us/doc/165x107/56814299550346895daecb0a/introduction-to-upper-air-measurements-with-radiosondes-and-other-in-situ-observing-5692a45625d20.jpg)
