radio aeronomy at onsala space observatory
Post on 01-Jan-2016
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Pressure broadening
22.222 22.224 22.226 22.228 22.23 22.232 22.234 22.236 22.238 22.24
-0.05
0
0.05
0.1
0.15
0.2
Frequency [GHz]
Brig
tnes
s te
mpe
ratu
re [
K]
Sky switched H2O at 22 GHz Frequency switched CO at 115 GHz
115.262 115.267 115.272 115.277-20
-19
-18
-17
-16
-15
-14
Frequency [GHz]B
right
ness
tem
pera
ture
[K
]
Tcold can be estimated assuming constant Trec
2
11
1
280 1300.25
280 325
280 300.50
280 250
cold rec cold
hot cold hot cold
hot reccold
cold hot cold
rec hot rec
cold
rec
cold
rec
P T TA
P P T T
A T TT
AdT T T
dT A T T
dTCO
dT
dTH O
dT
Sky as cold load
( ) 1
b bg eff
eff b
eff bg
b T hot coldhot cold
eff bgb T hot cold
hot cold eff cold
b T amb eff ambhot cold
T T e T e
T Te
T T
PT z T T e
P P
T TPT z T T
P P T T
PT z T if T T
P P
Teff is estimated from radiosonde data
Traditionally Teff = 0.95Tground
2 2
, 90
0.95, 0.05
0.90, 0.10
5
eff ground b
eff
T T T
H O H O
CO CO
T K
Stand alone calibration using skydip method
/ sin / sin
/ sin / sin
( ) 1
( , ) ( , )
1
can be calculated
b hot coldhot cold
b bg eff
h lb b b eff bg
h hb hot bg eff
hot cold
PT T T
P P
T T e T e
T T l T h T T e e
PT T T e T e
P P
Optical depth from skydip and dual channel radiometer
196 198 200 202 204 206 208
0.05
0.1
0.15
0.2
0.25
0.3
Day of 2001
Trop
osph
eric
opt
ical
dep
th
Elevation and tropospheric opacity change at 22 GHz
288 289 290 291 292 293 294 295 296 297 2985
10
15
20
25
30
35
Day of 2001
Ele
vatio
n [d
eg]/
optic
al d
epth
[ne
pers
*100
] u/
l
0 50 100 150 200 250 300 350140
150
160
170
180
190
200
210
220
230
240
250
Tem
p. a
t 87
km
[K
]
Day of 2002
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