104
W.T. Liu et al.
Fig. 6.8 Bin-average of (a)
U N , (b) normalized radar
cross section at vertical, and
(c) horizontal polarization
measured by QuikSCAT for
12 hurricanes as a function of
co-located Hwind. Error bars
represent 1 standard deviation
of data in each bin
scatterometers that would be sensitive to hurricane-scale winds (Esteban-Fernandez,
2006). As seen in Section 6.2, flow separation occurs at high winds and conventional
formulations of drag coefficient fail. Although retrieving the very strong winds of
a hurricane may not be an important and practical way to use the scatterometer, its
measurements are significant not only in revealing the relation between wind and
stress, but also in studying oceanic feed back to the dynamic forcing that is critical
in hurricane maintenance and intensification.
6.4 Geophysical Model Function for Stress Retrieval
6.4.1 Equivalent Neutral Wind Retrieval
At present, QuikSCAT geophysical retrieval is through GMF-W, which relates the
scatterometer normalized radar cross-section σ 0 with U N , as
σ 0 = f (U N ,χ ,ϑ,p)
(6.7)
W.T. Liu et al.
Fig. 6.8 Bin-average of (a)
U N , (b) normalized radar
cross section at vertical, and
(c) horizontal polarization
measured by QuikSCAT for
12 hurricanes as a function of
co-located Hwind. Error bars
represent 1 standard deviation
of data in each bin
scatterometers that would be sensitive to hurricane-scale winds (Esteban-Fernandez,
2006). As seen in Section 6.2, flow separation occurs at high winds and conventional
formulations of drag coefficient fail. Although retrieving the very strong winds of
a hurricane may not be an important and practical way to use the scatterometer, its
measurements are significant not only in revealing the relation between wind and
stress, but also in studying oceanic feed back to the dynamic forcing that is critical
in hurricane maintenance and intensification.
6.4 Geophysical Model Function for Stress Retrieval
6.4.1 Equivalent Neutral Wind Retrieval
At present, QuikSCAT geophysical retrieval is through GMF-W, which relates the
scatterometer normalized radar cross-section σ 0 with U N , as
σ 0 = f (U N ,χ ,ϑ,p)
(6.7)