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Annual<br />
DJF<br />
MAM<br />
JJA<br />
SON<br />
Observed<br />
Mean<br />
1970-99<br />
<strong>Turks</strong> <strong>and</strong> <strong>Caicos</strong> Isl<strong>and</strong>s: Country scale changes in Rainfall Extremes<br />
Observed<br />
Trend<br />
1960-2006<br />
mm Change<br />
in mm<br />
per<br />
decade<br />
A2<br />
A1B<br />
B1<br />
A2<br />
A1B<br />
B1<br />
A2<br />
A1B<br />
B1<br />
A2<br />
A1B<br />
B1<br />
A2<br />
A1B<br />
B1<br />
3.10. Hurricanes <strong>and</strong> Tropical Storms<br />
Projected changes by Projected changes by Projected changes by<br />
the 2020s<br />
the 2050s<br />
the 2080s<br />
Min Median Max Min Median Max Min Median Max<br />
Maximum 5-day Rainfall (RX5day)<br />
Change in mm Change in mm<br />
28<br />
-14 -1 17 -18 -3 11<br />
-18 0 12 -16 0 29<br />
-13 0 23 -15 -4 18<br />
-9 0 9 -9 1 9<br />
-7 0 9 -9 0 9<br />
-7 -1 8 -8 0 3<br />
-12 -4 14 -18 -7 6<br />
-14 -3 12 -15 -4 13<br />
-8 -1 12 -10 0 25<br />
-16 -3 11 -21 -6 -1<br />
-16 -3 3 -28 -5 0<br />
-13 -2 18 -13 -3 5<br />
-11 -4 13 -18 -2 12<br />
-19 0 12 -13 0 33<br />
-11 0 22 -13 -3 10<br />
Historical <strong>and</strong> future changes in tropical storm <strong>and</strong> hurricane activity have been a topic of heated debate in<br />
the climate science community. Drawing robust conclusions with regards to changes in climate extremes is<br />
continually hampered by issues of data quality in our observations, the difficulties in separating natural<br />
variability from long-term trends <strong>and</strong> the limitations imposed by spatial resolution of climate models.<br />
Tropical storms <strong>and</strong> hurricanes form from pre-existing weather disturbances where sea surface<br />
temperatures (SSTs) exceed 26˚C. Whilst SSTs are a key factor in determining the formation, development<br />
<strong>and</strong> intensity of tropical storms, a number of other factors are also critical, such as subsidence, wind shear<br />
<strong>and</strong> static stability. This means that whilst observed <strong>and</strong> projected increases in SSTs under a warmer<br />
climate potentially exp<strong>and</strong> the regions <strong>and</strong> periods of time when tropical storms may form, the critical<br />
conditions for storm formation may not necessarily be met (e.g. Veccchi <strong>and</strong> Soden, 2007; Trenberth et al.,<br />
2007), <strong>and</strong> increasing SSTs may not necessarily be accompanied by an increase in the frequency of tropical<br />
storm incidences.<br />
Several analyses of global (e.g. Webster et al., 2005) <strong>and</strong> more specifically North Atlantic (e.g. Holl<strong>and</strong> <strong>and</strong><br />
Webster, 2007; Kossin et al., 2007; Elsner et al., 2008) hurricanes have indicated increases in the observed<br />
record of tropical storms over the last 30 years. It is not yet certain to what degree this trend arises as part<br />
of a long-term climate change signal or shorter-term inter-decadal variability. The available longer term<br />
records are riddled with in homogeneities (inconsistencies in recording methods through time) - most<br />
significantly, the advent of satellite observations, before which storms were only recorded when making<br />
l<strong>and</strong>fall or observed by ships (Kossin et al., 2007). Recently, a longer-term study of variations in hurricane