532
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g260
co
:;
~ 240
CI>
a.
~220
I..
~200
c
E
.g> 180
III
c
.. .
~'60
,..,
20
Angle ot incidence: 45 deg.
Polarizatton: V8f1tcal
:a::===--~==::::::::==;;:.
::::~~~~~~-~:~~=::~i~~~;=:
~--/'
...•..........•........ .,c .....................................•................•....••..•...
.............. ~:.~ ................................................••.•..................
60
Frequency (GHz)
80
,00
2Wr-------------------------------------------,
~
~ 240
~
~220
I. .
~200
C
E C>
-c 180
III
c
(If
~'60
,..,
20
............................. ,;r.:.:::::::====-.====-.==.==.: ..... .
/ ' / '
Anglo of incidenco: 45 dog.
/ '
Polarization: Vortical
···········/··························Ak·i;;;p;.-;;;,,;;:~s·c···· .................. .
/'/'
--K·············I ~~ico ~~~ ~~ 1 000
- . - - -• • • • • • • • • • • •
60
Frequency (GHz)
80
'00
260r-----------------------------------------,
~
::l
Gi 240
lii
a.
~220
..
:200
c
1:
0>
-'::180
III
C
..
~160
'40 20
=-I-==-.".-~ .. "" ... ~.:.=.:::::::::::::::::::::::::::::::::::::::~ ..... .
=~=:=:~=:::-~~~~~~~~
/"
Ang)e ot incidence: 45 deg.
, / /
Polarizatton: Vettical
·····-·····-7··································Aj;.· __ ,;,;;.;;::2·C··················
/ /
..~ ..... ml~ ~~ico ~~.~ ~*~I···· __ · __ · __ m
60
Frequency (GHz)
80
'00
M. Hallikainen
Figure 19.3: Mean brightness temperatures of ice types and open water measured in the Baltic
Sea using a helicopter-borne radiometer (Kurvonen and Hallikainen, 1995a). (a) Dry ice/snow
conditions (air temperature _lOa C), 13 February 1992 (b) Wet ice/snow conditions (air temperature +0.5 °C), 13 March 1992 (c) Refrozen ice/snow conditions (air temperature -2°C),
17 March 1992.