Classification of CryoSat-2 Radar Echoes - Towards an Interdisciplinary Approach in Earth System Science - page 142

Fig. 3 CryoSat-2 monthly
mean radar freeboard from
December 2013, using a 40 %
retracker threshold. The black
line shows the CryoSat-2
ground track that is
considered in this study

CS-2 track

Radar freeboard in (m)

0.2 0.3 0.4 0.5 0.6 0.7 0.8

0.0 0.1

between FYI and MYI can be seen in the fact that if we use the MYI thresholds for
FYI we discard 86 % of the FYI waveforms.
Figure 4 b shows the left- and right-peakiness along the CryoSat-2 track. Within
the MYI the left-peakiness reveals a mean value of 9.0 (Table 2 ) whereas for FYI
we

nd a mean PP l of 32.0. Furthermore the scattering for FYI is higher than for
MYI. The right-peakiness PPl. r shows overall less scattering compared to PPl. l .It
reveals mean values of 5.6 for MYI and 10.1 for FYI. The mean difference between
FYI and MYI is lower than for PPl l but also shows higher values for FYI (Table 2 ).
In coincidence with negative outliers in the MYI zone in Fig. 4 awe

find increased

values for PPl. r and PP l .
Considering the biased waveforms in Table 2 we nd PP l values of 21.5 for FYI

and 38.7 for MYI. These values are signi cantly higher than the mean value for

MYI, but in the range of the mean PPl l for FYI. On the other hand, the PPl r for MYI
is close to the mean PP r of the unbiased MYI waveforms.

4 Discussion

Waveforms from FYI and MYI are of signi cantly different nature, which has been

already investigated in Zygmuntowska et al. ( 2013 ). Surface properties of MYI,
involving snow cover and surface roughness, cause a shallow echo power distri-
bution in the waveform whereas for FYI we

find a steeper leading edge (Fig. 2 )
which results in increased left- and right peakiness values (Fig. 4 b).