Coral bleaching
Thermal stress
indices
Coral
Reefs - sites: 1871 to date
During 1997-1998
mass
coral
bleaching was observed on many of the world’s coral reefs (See
also "Status of the World’s Coral Reefs:"
1998,
2000 &
2002).
There has also been increased number of reports of
mass coral bleaching events since the mid-1970s (e.g. Glynn, 1996)
coinciding with an increased rate of warming of global temperatures
(e.g. IPCC 2001) and growing concern about the potential impacts of
global warming due to the enhanced Greenhouse effect on the frequency
of such events (e.g. Hoegh-Guldberg, 1999). These large-scale coral
bleaching events appear primarily due to unusually warm sea surface
temperatures (SSTs) during the warm water season at affected coral
reef sites. Lough (2000) published indices, for the period 1903-1999,
of thermal stress at 47 global coral reef sites that had bleached
during 1997-98.
These indices showed that the frequency of warm season
extremes had increased since the 1970s and that the degree of thermal
stress during 1997-98 was the highest on record.
These thermal stress indices have recently been
extended back to 1871 using the UK Hadley Centre global monthly SST
compilation up to 1999 and updated to the present using NOAA NCEP EMC CMB Global Reyn-Smith OIv2 blended satellite and observations data set.
 UK
Hadley Centre
OIv2
blended satellite and observations data set
The "thermal stress" or omonth
indices presented here are determined for each year and site and combine both the magnitude and
duration of warm season SST anomalies. The base period for
calculating SST anomalies was 1982-1999, common to the two data
sets.
Thermal
stress indices
The thermal stress indices cover the period
1871 through to current date and will be up-dated at regular intervals.
 Figure
1 |
Average annual
maximum SSTs were extracted and anomalies above this mean summed
for the months each year this average was exceeded at each of 50
sites. |
|
Figure
2 |
Annual thermal
stress indices averaged over all 50 sites. |
|
Figure
3 |
Annual thermal
stress
indices averaged from 18 sites in the Indian Ocean
and Middle East. |
|
Figure
4 |
Annual
thermal stress
indices averaged from 9
sites in southeast Asia. |
|
Figure
5 |
Annual thermal
stress
indices averaged from 11
sites in the Pacific Ocean. |
|
Figure
6 |
Annual thermal
stress
indices averaged from 12 sites in the Caribbean and
Atlantic Ocean. |
References
-
Glynn, PW (1996) Coral reef bleaching: facts,
hypotheses and implications. Global Change Biology 2:
495-509.
-
Hoegh-Guldberg, O (1999) Climate change, coral
bleaching and the future of the world’s coral reefs. Marine
and Freshwater Research 50: 839-866
-
IPCC (2001) Climate Change 2001: The Scientific
Basis, Cambridge University Press, 944pp (see also http://www.ipcc.ch/)
-
Lough, JM (2000) 1997-98: Unprecedented thermal
stress to coral reefs? Geophysical Research Letters 27:
3901-3904
Contact
Dr. Janice Lough
Email:
j.lough@aims.gov.au
See also:
Coral
bleaching index - current and
archival information covering the past several years
December 18, 2008
|
20021218