Number 98, November 2008
The Island
Climate Update
Collaborators
Pacific Islands National
Meteorological Services
Australian Bureau of
Meteorology
Meteo France
NOAA National
Weather Service
NOAA Climate
Prediction Centre
(CPC)
International Research
Institute for Climate
and Society
European Centre
for Medium Range
Weather Forecasts
UK Met Office
World Meteorological
Organization
MetService of
New Zealand
October’s climate
•
The South Pacific Convergence Zone (SPCZ) was active across
southern Papua New Guinea, Vanuatu, and New Caledonia this
past month, and was displaced southwest of its normal position.
•
Very suppressed convection across much of the region, particularly
near Western Kiribati and south of the Equator from Nauru
southeast to the Society Islands.
•
Below normal rainfall for many areas in the South Pacific, including
Samoa and southwestern French Polynesia, but above normal
rainfall in Vanuatu.
El Niño/Southern Oscillation (ENSO), seasonal
rainfall, and sea surface temperature forecasts
•
Neutral ENSO conditions exist in the tropical Pacific at present.
Most climate models project neutral ENSO conditions persisting
into early 2009.
•
Below average rainfall is forecast for Western Kiribati, the
Marquesas, the Society Islands, Tuvalu, Tokelau, Wallis & Futuna,
Samoa, the Northern Cook Islands, and the Tuamotu archipelago.
•
Above normal rainfall is expected for Papua New Guinea, New
Caledonia, Vanuatu, and Tonga for the coming three months.
•
Normal to above normal SSTs are forecast for the southwestern half
of the southwest Pacific region. Normal to below normal SSTs are
forecast for the northeast half of the southwest Pacific, except for
the Society Islands which are projected to have near normal SSTs
.
The Island Climate Update, No. 98, November 2008
Page 2
Climate developments in October 2008
Outgoing Long-wave Radiation (OLR) anomalies, in Wm
2
are represented
by hatched areas. High radiation levels (yellow) are typically associated
with clearer skies and lower rainfall, while cloudy conditions lower the
OLR (blue) and typically result in higher rainfall. The October 2008 position
of the South Pacific Convergence Zone (SPCZ) is contracted slightly toward
Papua New Guinea and displaced southwest of its normal position. The
average position of the SPCZ is identified by the dashed green line, which
is based on mean January rainfall for the South Pacific (after Linacre and
Geerts, 1998). Mean sea level (MSL) pressure anomalies (in hPa) are shown
as grey solid (high pressure) and dashed (low pressure) lines (adapted from
Bureau of Meteorology, Australia).
Soil moisture in October 2008
Estimated soil moisture conditions at the end of October 2008,
using monthly rainfall data. Soil moisture projections for individual
Pacific Island countries are dependent on data availability at the
time of publication.
E
stimates of soil moisture shown in the map (right) are
based on monthly rainfall for one station in each country.
Currently there are not many sites in the water balance model,
but more stations will be included in the future.
The information displayed is based on a simple water balance
technique to determine soil moisture levels. Addition of
moisture to the available water already in the soil comes
from rainfall, with losses via evapotranspiration. Monthly
rainfall and evapotranspiration are used to determine the soil
moisture level and its changes. Please note that these soil
moisture calculations were made at the end of the month,
and for practical purposes, generalisations were made about
the available water capacity of the soils at each site.
Nadi (Fiji) and Rarotonga (Southern Cook Islands) project
dry soil moisture conditions. Soils continued to be moist
(at field capacity) for the time of year at Port Vila (Vanuatu)
and Hanan (Niue), while moderate soil moisture is projected
for Apia (Samoa), Nuku’alofa (Tonga), and Tarawa (Western
Kiribati).
T
he South Pacific Convergence Zone (SPCZ) activity
strenghtened in October relative to previous months.
A consolidated region of enhanced rainfall was observed
in satellite data during October 2008, extending southeast
from southern Papua New Guinea toward Vanuatu
and New Caledonia. A localised region of suppressed
convection expanded during the month to the south of the
Equator, encompassing northeast of the Solomon Islands,
and extending through the central southwest Pacific to
Pitcairn Island. The regional circulation for the month was
characterised by more frequent anticyclones over eastern
Australia, with a ridge of high pressure extending over the
Tasman Sea and the southwest Pacific to the north of New
Zealand. Lower than normal pressure also developed to the
north of the Marquesas Islands.
Rainfall was below average for many countries in the
Southwest Pacific during October 2008. A new monthly
low rainfall total was recorded at Bora Bora in the Society
Islands, which received 14 mm of rainfall (14% of normal).
Elsewhere in the eastern half of the Southwest Pacific, the
stations in the Northern and the Southern Cook Islands, the
Tuamotu archipelago, and the Austral Islands all recorded
20–50% of normal rainfall, with the exception of 175.8 mm
(105% of normal) occurring at Rapa on the southern margin
of the Austral Islands. Many stations in Fiji and Samoa also
received between 25–75% of normal rainfall.
Australia
New Zealand
Fiji
New Caledonia
Vanuatu
Solomon Is
Samoa
Tonga
Niue
E Kiribati
Papua New Guinea
S Cook Is
N Cook Is
Society Is
W Kiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Caroline Is
Tuamotu Is
Pitcairn
EQUATOR
In Samoa, the continuation of well–below normal rainfall
has meant water restrictions are still in place in Apia, which
experienced the lowest monthly rainfall total for the past
five years. Western Kiribati also received lower than normal
rainfall, with 37% of normal recorded at Tarawa. Eastern
Kiribati recorded well below normal rainfall during the
month. 5.1 mm (8% of normal) fell on 4 October in Kiritimati,
which accounted for the entire monthly total for that island.
In the western Southwest Pacific, rainfall totals were near
to above normal in the southwestern Solomon Islands,
and also in northern and western New Caledonia, with a
high monthly rainfall total recorded at La Roche (215 mm,
256% of normal). A new monthly record was established
at Bauerfield, Vanuatu, which recorded 327 mm (461% of
normal) rainfall.
Wet
Moderate
Dry
Wet
Moderate
Dry
Wet
Moderate
Dry
Wet
Moderate
Dry
October 2008
October 2007
Island Group
Location
Rainfall
(mm)
% of
avg
Comments
Vanuatu
Bauerfield
327
461
Record high
Vanuatu
Sola
548
151
Highest monthly
total in the region
New Caledonia
La Roche
215
256
Very high
Society Islands
Bora Bora
14
14
Record low
Western Kiribati
Kiritimati
5
8
Very low
Australia
Townsville
4
15
Very low
The Island Climate Update, No. 98, November 2008
Page 3
Mean sea surface temperatures (ºC) for October 2008
Sea surface temperature anomalies (ºC) for October 2008
Forecast validation: August to October 2008
-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.5 1.0 1.5 2.0 2.5 3.0
Australia
New Zealand
Fiji
New Caledonia
Vanuatu
Solomon Is
Samoa
Tonga
Niue
E Kiribati
Papua New Guinea
S Cook Is
N Cook Is
Society Is
W Kiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Fed States of Micronesia
Tuamotu Is
Pitcairn
EQUATOR
Wallis & Futuna
10 12 14 16 18 20 22 24 26 28 30 32
Australia
New Zealand
Fiji
New Caledonia
Vanuatu
Solomon Is
Samoa
Tonga
Niue
E Kiribati
Papua New Guinea
S Cook Is
N Cook Is
Society Is
W Kiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Fed States of Micronesia
Tuamotu Is
Pitcairn
EQUATOR
Wallis & Futuna
El Niño/Southern Oscillation (ENSO)
D
uring October, ENSO-neutral conditions were
well established in the equatorial Pacific ocean,
but the Tropical Pacific atmosphere continued to
exhibit La Niña-like characteristics. The SOI remains
positive at around +1.5 (an August-October mean of
+1.2), consistent with enhanced trade winds about
and west of the Date Line.
SST anomalies in October were close to neutral
across the Equatorial Pacific: The NINO3 anomaly for
October was +0.2°C (3-month mean +0.6°C), and
the NINO4 anomaly was zero (ASO mean 0.1°C).
Equatorial subsurface temperature anomalies are
now relatively weak, with a -1 to -2°C anomaly centre
near 140°W (weakened from -3°C in September).
Tropical Pacific precipitation patterns continue
to show a La Niña signal, with the TRMM ENSO
precipitation index at -1.26 for October, after
weakening earlier in the month. OLR anomalies
show suppressed Equatorial convection about and
west of the Date Line. A convective pulse associated
with the Madden-Julian Oscillation is passing
through the Indonesian region during late October,
and is expected to move over the Western Pacific in
early November. This is on average associated with
negative MSLP anomalies over New Zealand and
positive anomalies to the north. The SPCZ was more
active during October than last month. The Southern
Annular Mode (SAM) was predominantly positive
in October, and is predicted to continue along a
positive trend into November.
Almost all models indicate neutral conditions
continuing through to the end of autumn 2009. The
NCEP discussion of 9 October indicates ENSO-
neutral conditions through to early 2009, with a small
possibility of a return to La Niña conditions. The IRI
summary of 16 October gives a 90% probability
of ENSO-neutral conditions in the October to
December season, and the probability of El Niño 2%
and La Niña only 8%. The Australian weekly tropical
summary of 21 October suggests ENSO-neutral
conditions persisting through the austral autumn.
A
large region of suppressed convection was forecast over
Tuvalu, Tokelau, the Northern Cook Islands, Tuamotu,
the Society Islands, Pitcairn Island, and the Marquesas during
August to October 2008, with average–to–below or below
average rainfall expected for those countries. Enhanced
convection for the same period was projected from Papua
New Guinea extending in a band southeast toward Vanuatu
and through Tonga, with above average rainfall forecast for
those countries. Near–to–above average rainfall was forecast
for Fiji, Niue, the Solomon Islands and New Caledonia. No
clear precipitation guidance was offered for Eastern Kiribati,
Wester Kiribati, the Southern Cook Islands or the Austral
Islands.
The rainfall outlook for the August–October 2008 period
was very good compared to what was forecast, the island
group global station ‘hit’ rate being 77%, 19% higher than
average for forecasts made during August and 16% higher
than the average for all months combined. Rainfall totals
were overestimated for the west-central part of the South
Pacific, including Niue and Tonga and for the eastern fringe
of French Polynesia.
Forecast statistics compiled over the last nine years indicate
the multi-ensemble strike rate will continue to improve
toward the end of the year.
The Island Climate Update, No. 98, November 2008
Page 4
Tropical Pacific rainfall – October 2008
Rainfall totalling 200% or more is considered well above average. Totals of 40% or less are normally well below average. Highlighted values are
new records.
Data are published as received and may be subject to change after undergoing quality control checks. N/A denotes data unavailability at the time
of publishing, and * denotes synoptic values.
Territory and
station station
name
October 2008
rainfall
total (mm)
October 2008
percent of
average
Australia
Cairns Airport
82
199
Townsville Airport
4
15
Brisbane Airport
55
59
Sydney Airport
67
85
Cook Islands
Penrhyn
85
49
Aitutaki
N/A
N/A
Rarotonga Airport
40
39
Fiji
Rotuma Island
255
75
Udu Point
51
31
Nadi Airport
69
67
Nausori
221
108
French Polynesia
Hiva Hoa, Atuona
83
85
Bora Bora
14
14
Tahiti – Faa’a
28
28
Tuamotu, Takaroa
23
20
Gambier, Rikitea
N/A
N/A
Tubuai
42
32
Rapa
48
41
Kiribati
176
105
Tarawa
48
37
Kanton
53
77
New Zealand
Kaitaia
76
76
Whangarei Airport
56
51
Auckland Airport
91
115
New Caledonia
Ile Art, Belep
30
55
Koumac
28
101
Ouloup
72
112
Ouanaham
101
154
Poindimie
115
93
La Roche
215
256
La Tontouta
40
93
Noumea
42
85
Moue
110
138
Territory and
station station
name
October 2008
rainfall
total (mm)
October 2008
percent of
average
Niue
Hanan Airport
114
61
Liku
217
148
North Tasman
Lord Howe Island
79
59
Norfolk Island
27
30
Raoul Island
27
34
Samoa
Faleolo Airport
139
60
Apia
121
53
Nafanua
168
N/A
Afiamalu
161
N/A
Maota
146
N/A
Solomon Islands
Taro
N/A
N/A
Munda
198
80
Auki
266
125
Honiara
40
26
Henderson
93
107
Kira Kira
341
142
Santa Cruz, Lata
447
127
Tonga
Niuafo’ou
N/A
N/A
Mata’aho Airport
N/A
N/A
Lupepau’u
133
75
Salote Airport
184
202
Nuku’alofa
70
55
Fua’amotu Airport
42
41
Tuvalu
Nanumea
81
48
Nui Island
138
71
Funafuti
172
64
Nuilakita
N/A
N/A
Vanuatu
Sola
548
151
Pekoa
328
182
Lamap
276
242
Port Vila
250
272
Tanna/Whitegrass
98
N/A
Aneityum
237
249
The Island Climate Update, No. 98, November 2008
Page 5
Rainfall outlook map for November 2008 to January 2009
Tropical rainfall and SST outlook: November 2008 to January 2009
NOTE: Rainfall and sea surface termperature estimates for Pacific Islands for the next three months are given in the tables below. The tercile probabilities (e.g.,
20:30:50) are derived from the averages of several global climate models. They correspond to the odds of the observed rainfall or sea surface temperatures being in
the lowest one third of the distribution, the middle one third, or the highest one third of the distribution. For the long term average, it is equally likely (33% chance)
that conditions in any of the three terciles will occur. *If conditions are climatology, we expect an equal chance of the rainfall being in any tercile.
D
uring the November 2008–January 2009 forecast
period, a region of suppressed convection is likely to
encompass the central and eastern Southwest Pacific, in a
region extending from Western Kiribati to the Marquesas
Islands and the Society Islands, including Tuvalu, Tokelau,
Wallis & Futuna, Samoa, the Northern Cook Islands, and
the Tuamotu archipelago. Below normal or near–to–below
normal rainfall is expected for those countries.
Enhanced convection is expected to be focused near Papua
New Guinea, and also near Vanuatu, New Caledonia, Tonga,
Fiji, and Niue with above average rainfall. Near–to–above
average rainfall is forecast for the Southern Cook Islands,
the Austral Islands, and Pitcairn Island for the next three-
month period. No clear precipitation forecast is offered for
the Solomon Islands.
SSTs are expected to be above normal in a band extending
from near Papua New Guinea, southeast to Fiji, including
Vanuatu, New Caledonia, and the Solomon Islands. Near –
above normal SSTs are forecast for Niue, the Southern Cook
Islands, the Austral Islands and Pitcairn Island. Normal to
below normal SSTs are forecast for the northeastern sector
of French Polynesia, including the Tuamotu archipelago and
the Society Islands, Tuvalu, Tokelau, and both Eastern and
Western Kiribati.
The confidence in the forecast model skill for this seasonal
rainfall outlook is moderately high for most Pacific Island
countries. In the past, the average region-wide hit rate for
forecasts issued in November is 64%, 4% higher than the
long-term average for all months combined. The SST forecast
confidence is moderate for this period.
Island Group
Rainfall Outlook
Outlook confidence
Papua New Guinea
20:30:50 (Above)
Moderate-High
New Caledonia
20:35:45 (Above)
Moderate-High
Niue
20:35:45 (Above)
Moderate-High
Tonga
20:35:45 (Above)
Moderate-High
Vanuatu
20:35:45 (Above)
Moderate-High
Fiji
25:35:40 (Near or Above)
Moderate
Austral Islands
25:35:40 (Near or Above)
Moderate-High
Cook Islands (Southern)
25:35:40 (Near or Above)
Moderate-High
Pitcairn Island
25:35:40 (Near or Above)
Moderate-High
Solomon Islands
30:35:35 (Climatology)
Moderate-High
Kiribati (Eastern)
40:35:25 (Near or Below
)
Moderate-High
Samoa
40:40:20 (Near or Below)
Moderate
Cook Islands (Northern)
45:35:20 (Below)
Moderate-High
Wallis & Futuna
45:35:20 (Below)
Moderate
Marquesas
45:30:25 (Below)
Moderate
Kiribati (Western)
45:30:25 (Below)
Moderate
Society Islands
50:30:20 (Below)
Moderate-High
Tokelau
50:30:20 (Below)
Moderate-High
Tuamotu Islands
50:30:20 (Below)
Moderate-High
Tuvalu
50:30:20 (Below)
Moderate-High
Australia
New Zealand
Fiji
New Caledonia
Vanuatu
Solomon Is
Pitcairn
Samoa
Tonga
Niue
E Kiribati
Papua New Guinea
N Cook Is
S Cook Is
Society Is
W Kiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Fed States of Micronesia
Tuamotu Is
EQUATOR
Wallis & Futuna
NO
FORECAST
SST outlook map for November 2008 to January 2009
Island Group
SST Outlook
Outlook confidence
Fiji
20:35:45 (Above)
Moderate
New Caledonia
20:35:45 (Above)
Moderate
Papua New Guinea
20:35:45 (Above)
Moderate
Vanuatu
20:35:45 (Above)
Moderate
Austral Islands
20:40:40 (Near or above)
Moderate
Cook Islands (Southern)
20:40:40 (Near or above)
Moderate
Pitcairn Island
20:40:40 (Near or above)
Moderate
Samoa
20:40:40 (Near or above)
Moderate
Wallis & Futuna
20:40:40 (Near or above)
Moderate
Niue
25:35:40 (Near or above)
Moderate
Solomon Islands
25:35:40 (Near or above)
Moderate
Tonga
25:35:40 (Near or above)
Moderate
Society Islands
30:45:25 (Near Normal)
Moderate-High
Tuamotu Islands
30:40:30 (Near Normal)
Moderate-High
Cook Islands (Northern)
35:40:25 (Near or Below)
Moderate-High
Marquesas
35:40:25 (Near or Below)
Moderate
Tokelau
35:40:25 (Near or Below)
Moderate-High
Tuvalu
35:40:25 (Near or Below)
Moderate-High
Kiribati (Western)
40:35:25 (Near or Below)
Moderate
Kiribati (Eastern)
40:40:20 (Near or Below)
Moderate
Australia
New Zealand
Fiji
New Caledonia
Vanuatu
Solomon Is
Pitcairn
Samoa
Tonga
Niue
E Kiribati
Papua New Guinea
N Cook Is
S Cook Is
Society Is
W Kiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Fed States of Micronesia
Tuamotu Is
EQUATOR
Wallis & Futuna
Near or
above
Above
Near normal
Near or
below
Below
NO
FORECAST
NO
FORECAST
The Island Climate Update, No. 98, November 2008
Page 6
Acknowledgements
This bulletin is produced by NIWA and made possible
with financial support from the New Zealand Agency
for International Development (NZAID), with additional
support from the Pacific Islands Applied Geosciences
Commission (SOPAC) and the Secretariat for the
Pacific Regional Environmental Programme (SPREP).
This summary is prepared as soon as possible following the
end of the month, once the data and information are received
from the Pacific Island National Meteorological Services
(NMHS). Delays in data collection and communication
occasionally arise. While every effort is made to verify
observational data, NIWA does not guarantee the accuracy
and reliability of the analysis and forecast information
presented, and accepts no liability for any losses
incurred through the use of this bulletin and its content.
The contents of The Island Climate Update may be freely
disseminated, provided the source is acknowledged.
Requests for Pacific Island climate data should be directed
to the Meteorological Services concerned.
Cover Photo:
Wendy St George,
NIWA
Visit The Island Climate Update at:
www.niwascience.co.nz/ncc/icu
Your comments and ideas about The Island Climate
Update are welcome. Please contact:
Project Director: Dr Jim Salinger, NIWA,
Private Bag 109 695, Newmarket, Auckland,
New Zealand. E-mail:
j.salinger@niwa.co.nz
Forecasts:
Dr. Andrew Lorrey (South Pacific rainfall and SST) and the
NIWA National Climate Centre (ENSO)
ICU Editors:
Andrew Lorrey Email:
a.lorrey@niwa.co.nz
Jim Salinger Email:
j.salinger@niwa.co.nz
Harriet Palmer Email:
h.palmer@niwa.co.nz
Sources of South Pacific rainfall data
This bulletin is a multi-national project, with important
collaboration from the following Meteorological Services:
American Samoa, Australia, Cook Islands, Fiji, French
Polynesia, Kiribati, New Caledonia, New Zealand, Niue,
Papua New Guinea, Pitcairn Island, Samoa, Solomon
Islands, Tokelau, Tonga, Tuvalu, Vanuatu, Wallis and
Futuna.
Improving Meteorological Information in Rural Communities
Jotham Napat, Salesa Kaniaha, and Brian Phillips, Vanuatu Meteorological Service (VMS)
S
ince 2000, the VMS has initiated vigorous awareness programs
throughout the country in an effort to educate rural communities
about weather and climate variability. The initiative has covered
remote regions that have previously not had the opportunity
to engage in climate change, meteorological, environmental,
hydrological, and geological awareness exercises. To date, the
VMS has covered 90% of the 83 inhabited islands of Vanuatu, but
only about 40% of the rural population. This is due to the sparsely
distributed settlements in the islands and lack of sufficient funds.
Raising awareness of weather and climate through radio programs
often falls short due to poor coverage. As a result, new strategic
awareness programs need to be developed to cover these remote
areas. Information distribution will be assisted by localising source
texts that contain detailed meteorological and climate change
information in schools, and improving access to more TV programs,
more media coverage, and additional profile-raising interactions
about climate change and climate variability in rural communities.
A survey conducted by VMS in 2002 showed that people in
rural regions can understand climate and weather concepts
better when they are presented through multimedia (power
point presentations), suggesting understanding can be
facilitated using a combination of audio/visual techniques.
Awareness medium that captures interest (ranking) in %
0
20
40
60
80
Multimedia
Posters
Leaflets
Radio
Video Doc Drama (WSB)
T-Shirt
Type of Material
Interest level for each medium (%)
High
Average
Low
Different mediums used by the VMS for raising awareness and their
effectiveness (percentage) to convey messages from the local perspective.
Climate bulletins with the relevant information that can help
decision making at the community level have not been overly
successful in permeating rural areas. Many communities are still in
the grey zone between traditional knowledge of the environment
and science when it comes to interpreting meteorological and
The Island
Climate Update
climatological phenomenon. There are also some cultural barriers
that hinder the acceptance of meteorological information and
advice. Events like La Niña or El Niño are not well known in
Vanuatu. There are historical accounts of extreme events having
occurred in the past, and traditional adaptive measures were
developed to alleviate impacts of these situations on the wellbeing
of communities. Most of the past extreme events have been in one
way or another viewed as the work of sorcerers. For example, The
drought related to the El Nino event of 1997/98, severely affected
the Vanuatu agriculture, livestock, and water sectors. Chiefs on one
island filed a case that led to the arrest of an individual, with the
belief that he was responsible for causing the drought. VMS will
continue to develop strategies and put in place systems that will
enable effective communication between meteorologists and the
local people to avoid unfortunate misunderstandings like this in
the future.
Topics which locals don't know much about
53
6
11
11
11
8
0
20
40
60
ENSO
Volcanoes
Climate
Change
Issues
Tsunamis Earthquakes Cyclones
(%)
The capacity of the VMS to provide accurate and timely climate
and weather information and improve understanding in rural
communities have recently increased with the introduction of the
Vanuatu Climate Update, Island Climate Update, and Seasonal
Climate Outlook for Pacific Island Country (SCOPIC) software.
VMS is also establishing an ‘ENSO Desk’ that will offer technical
assistance and promote a better understanding of ENSO (La Nina/El
Nino) and its impacts on different sectors in the country. It will also
enable the National Disaster Management Office and VMS to map
out the vulnerabilities of different islands to ENSO, and develop a
centralized information system on ENSO impacts. This information
can then be relayed to communities, and assist the development of
an alert system for provincial government use.