4 Discoveries About Tropical Cyclones Provided by Microwave Remote Sensing
65
different times and in different orbit swaths (e.g. Bentamy et al., 2003). This work
includes estimates of turbulent fluxes of latent and sensible heat.
4.2.4 Altimetry and TCs
An altimeter measures the distance between the sea surface and the satellite in a
narrow swath at nadir (about 7 km × 7 km). SEASAT carried an altimeter and
several more have followed on ERS 1 and ERS 2 and on the dedicated satellite,
launched in 1992, the Topography Experiment TOPEX/Poseidon (where Poseidon
was an experimental additional altimeter operated by the French Space Agency).
With a determination of the Earth’s average gravitational geoid over time, deviations
or Sea Height Anomalies (SHAs) can be determined. These allow interpretation in
terms of ocean currents and the heat content of upper ocean eddies. This latter aspect
has been developed for aid in determining the Tropical Cyclone Heat Potential,
TCHP, of warm eddies in the path of TCs.
Exceptionally high values of heat content have been linked to rapid intensification of a passing hurricane or typhoon. The early estimates of this possibility was
for hurricane Opal in the Caribbean sea (Shay et al., 2000). A notable example of
intensification while passing over an eddy is that of hurricane Katrina in 2005, as
illustrated in Figs. 4.4 and 4.5.
Fig. 4.4 Illustration of the Sea Height Anomaly present as hurricane Katrina passed it on its
approach to New Orleans, Louisiana, USA in August of 2005. The colours and size of the position
circles of the storm indicate the category rating of the storm at the time. Katrina intensified as she
passed over the warm eddy
65
different times and in different orbit swaths (e.g. Bentamy et al., 2003). This work
includes estimates of turbulent fluxes of latent and sensible heat.
4.2.4 Altimetry and TCs
An altimeter measures the distance between the sea surface and the satellite in a
narrow swath at nadir (about 7 km × 7 km). SEASAT carried an altimeter and
several more have followed on ERS 1 and ERS 2 and on the dedicated satellite,
launched in 1992, the Topography Experiment TOPEX/Poseidon (where Poseidon
was an experimental additional altimeter operated by the French Space Agency).
With a determination of the Earth’s average gravitational geoid over time, deviations
or Sea Height Anomalies (SHAs) can be determined. These allow interpretation in
terms of ocean currents and the heat content of upper ocean eddies. This latter aspect
has been developed for aid in determining the Tropical Cyclone Heat Potential,
TCHP, of warm eddies in the path of TCs.
Exceptionally high values of heat content have been linked to rapid intensification of a passing hurricane or typhoon. The early estimates of this possibility was
for hurricane Opal in the Caribbean sea (Shay et al., 2000). A notable example of
intensification while passing over an eddy is that of hurricane Katrina in 2005, as
illustrated in Figs. 4.4 and 4.5.
Fig. 4.4 Illustration of the Sea Height Anomaly present as hurricane Katrina passed it on its
approach to New Orleans, Louisiana, USA in August of 2005. The colours and size of the position
circles of the storm indicate the category rating of the storm at the time. Katrina intensified as she
passed over the warm eddy