"Climate Change and Southern Hemisphere Tropical Cyclones" International Initiative – Progress since the First International Conference on Indian Ocean Tropical Cyclones and Climate Change - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 23

results were obtained in the annual 945 hPa counts, but not in the 955 hPa
counts.
While some of the trends in the TC data appear to be artificial to a degree,
due to changes in TC observation practices and analysis techniques as discussed
above, it is possible that TC occurrences are subject to variability associated
with low-frequency climate modes, such as ENSO (Kuleshov et al., 2008;
Kuleshov et al., 2009a, 2009b), the Indian Ocean Dipole (Chan and Liu, 2009)
and the Pacific Decadal Oscillation (Goh and Chan, 2009), to the extent of
having a noticeable impact on the trends. The inclusion of these low-frequency
climate modes in the trend analysis is beyond the scope of this study, but will
be a topic of further investigation.
4. Historical Cyclone Data Portal
To provide a user-friendly means for accessing detailed information and data
on historical tropical cyclones for the SH, the first version of a specialised
website for disseminating results and data “Tropical Cyclones in the Southern
Hemisphere” was developed in 2007. Recently, a new design for the website
has been developed (Fig. 4; http://www.bom.gov.au/cyclone/history/tracks/)
(Kuleshov et al., 2011). Main features of this design are briefly presented in
this section.
The new tropical cyclone website has been developed using OpenLayers
platform (see for example Yim and Feng, 2009). This allows dynamic map
navigation, presenting detailed information for a selected region in the SH and
the display of changes in tropical cyclone intensity over the lifetime of a cyclone.
The features of the new web site are presented below using tropical cyclone
Ivan as an example.
Cyclone Ivan was a powerful tropical cyclone that struck Madagascar in
February 2008. It caused catastrophic damage to Madagascar estimated at >30
million dollars (2008 USD). In Sainte Marie Island, the worst hit area, 90% of
the infrastructure was destroyed. On mainland Madagascar, over 400,000 acres
(1,600 km 2 ) of cultivated crops were destroyed, leaving hundreds of families
without food. Over 330,000 people were left homeless, and the storm caused
93 deaths (Cyclone Ivan 2008 Wiki).
Best track of the TC Ivan extracted using the website's mapping function
is presented in Fig. 5. In Fig. 6, track of the cyclone Ivan is displayed over the
“Elevation and bathymetry” layer. Orange dots represent best track six-hourly
positions of the cyclone when its central pressure was estimated above 970
hPa and red dots represent the cyclone's positions when pressure was estimated
as equal to or below 970 hPa (an approximate pressure threshold for severe
tropical cyclones in the SH).
The dynamic map navigation feature of the new web site allows one to
examine the cyclone track over a selected region in detail. Dashed line connects
points of the tropical cyclone best track when the system was at a stage of