Number 101, February 2009
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
January’s climate
•
The South Pacific Convergence Zone (SPCZ) was displaced
southwest of its normal position and was very active.
•
Very suppressed convection near Western Kiribati and south of the
Equator from Nauru east to northern French Polynesia.
•
Normal to well above normal rainfall for many areas in the South
Pacific, with many new records established in Fiji.
El Niño/Southern Oscillation (ENSO), seasonal
rainfall, and sea surface temperature forecasts
•
La Niña-like conditions exist in the tropical Pacific. Many climate
models project continuation of La Niña through to the end of
summer 2009.
•
Below normal rainfall is forecast for Western Kiribati, Tuvalu,
Tokelau, the Northern Cook Islands, and the Society Islands.
•
Above normal rainfall is expected for New Caledonia, Niue, Tonga,
and Papua New Guinea.
•
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.
The Island Climate Update, No. 101, February 2009
Page 2
Climate developments in January 2009
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 January 2009 position
of the South Pacific Convergence Zone (SPCZ) was displaced southwest of
its normal position, and much more coherent than last month. The average
position of the SPCZ is identified by the dashed green line, which is based
on mean January rainfall for the South Pacific. Mean sea level (MSL) pressure
anomalies (in hPa) are shown as grey lines.
-90 -70 -50 -30 -20 -10 10 20 30 50 70 90
Australia
NewZealand
Fiji
NewCaledonia
Vanuatu
SolomonIs
Pitcairn
Samoa
Tonga
Niue
E Kiribati
Papua NewGuinea
NCook Is
S Cook Is
Society Is
WKiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
TokelauIs
Nauru
Fed States of Micronesia
Tuamotu Is
EQUATOR
Wallis & Futuna
H
H
H
H
Soil moisture in January 2009
Estimated soil moisture conditions at the end of January 2009,
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. 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), Hanan (Niue), Port Vila (Vanuatu), Rarotonga
(Southern Cook Islands), and Apia (Samoa) project moist
(at or near field capacity) soil moisture conditions. Soils are
moderate for the time of year at Nuku’alofa (Tonga).
T
he South Pacific Convergence Zone (SPCZ) activity was
displaced south and west of normal during January,
and was more consolidated than last month. A region of
enhanced rainfall due to intensified convection was observed
during January 2009 over northeast Australia, and in the
south Pacific extending from the Solomon Islands southeast
to the Southern Cook Islands. Very high amounts of rainfall
occurred within this band, and are highlighted in this issue.
Suppressed convection intensified during the month near
the Equator, and encompassed the region northeast of the
Solomon Islands that included Nauru and Western Kiribati,
and extended across the southwest Pacific to the Marquesas.
The regional circulation for the month was characterised by
more frequent high pressure across the northeastern half
of the South Pacific; and lower than normal pressures east
of northern New Zealand and south of the Southern Cook
Islands.
Many rainfall records were shattered in Fiji in January 2009
(see back page highlight article), with most stations receiving
140–450% of normal rainfall. Similarly, northeastern
Australia (220–250% or normal), Vanuatu (135–200% of
normal), and Tonga (120–340% of normal) received well
above normal rainfall for many stations. Enhanced rainfall
was also localised near Pitcairn Island. All of the reporting
stations for Tonga received greater than 300mm rainfall in
January, and two of those stations were close to or exceeded
previous monthly record highs.
Lower than normal rainfall was recorded at many stations in
French Polynesia, with Hiva Hoa in the Marquesas Islands
receiving 34 mm of rainfall (22% of normal). Elsewhere in
the eastern half of the southwest Pacific, the stations in the
Tuamotu archipelago and the Austral Islands all recorded
normal or below normal rainfall, except Rikitea, which
received a record high total of 433 mm (297% of normal).
Continuing the trend from last month, many stations in New
Caledonia received well below normal rainfall (30–60%)
during January. Northern New Zealand also experienced a
relatively dry month, with the northern part of the country
recording well below normal rainfall (20–60% of normal).
The Solomon Islands also had a relatively normal month,
except at Honiara and Henderson, which received 170–
Wet
Moderate
Dry
Wet
Moderate
Dry
Wet
Moderate
Dry
Wet
Moderate
Dry
January 2009
January 2008
Island Group
Location
Rainfall
(mm)
% of
avg
Comments
Fiji
Lautoka
1291
348
Record high;
Highest monthly
total in the region
Tonga
Fua’amotu
570
284
Record high
Fiji
Penang
1228
310
Record high
Tuamotu
Rikitea
433
297
Record high
Marquesas
Hiva Hoa
34
22
Very low
New Caledonia
Belep
60
25
Very low
190% 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
Tuamotu Is
Pitcairn
EQUATOR
The Island Climate Update, No. 101, February 2009
Page 3
Mean sea surface temperatures (ºC) for January 2009
Sea surface temperature anomalies (ºC) for January 2009
Forecast validation: November 2008 to January 2009
-3
-2
-1
0.5
2
3
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 January, La Niña conditions were
established in the equatorial Pacific Ocean, with
the tropical Pacific atmosphere exhibiting moderate
La Niña characteristics. The SOI remained positive
with a January value of +0.9 (NDJ mean +1.3),.
The easterly trade winds remained strong during
December about and west of the Date Line, now
have weaken slightly across the tropical Pacific, but
still appear to strongest around 160°E.
SST anomalies in December were below average
across the Equatorial Pacific: the NINO3 anomaly for
strengthened in January to –0.7°C (3-month mean
–0.3°C), as did the NINO4 anomaly which is –0.7°C
(OND mean 0.4°C). Equatorial subsurface anomalies
that strengthened at the thermocline in December
(with a –4°C anomaly centred near 140°W below
100m) now appear to be weakening somewhat in the
eastern equatorial Pacific with some weak warming
at the surface near South American Coast. West
of the dateline sub-surface warming appears to be
occurring and intensifying towards 160°W.
Tropical Pacific precipitation patterns continue to
exhibit La Niña characteristics, with the TRMM ENSO
precipitation index at -0.82 for January (up from
-1.34 in December). OLR anomalies show extremely
suppressed equatorial convection about and west
of the Date Line and the eastern Indian Ocean for
January as a whole, with enhanced convection over
the maritime continent and northern Australia. The
MJO in the Indian Ocean is weak and is expected to
remain so into the second week of February.
Several climate models assessed by NIWA predict
weakening La Niña conditions over the next three-
months (FMA). The majority indicate ENSO-neutral
conditions during late autumn and early winter
2009. The NCEP discussion of 8 January indicates
a continuation of below average sea surface
temperatures and continuation of La Niña through
early 2009. The IRI summary of 14 January indicates
A
region of suppressed convection was expected 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 was expected for those countries. Enhanced
convection was 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 was forecast for the Southern Cook Islands,
the Austral Islands, and Pitcairn Island, while no clear
precipitation forecast was offered for the Solomon Islands.
The rainfall outlook for the November 2008–January 2009
period was calculated for 17 island groups (one island had
a forecast of ‘climatology’, which is unscoreable, and three
did not report values). The global station ‘hit’ rate was 71%,
7% higher than average for forecasts made during November
and 10% higher than the average for all months combined.
Rainfall was overprojected for Vanuatu and New Caledonia,
and either over– or under– projected for parts of French
Polynesia.
a 55% chance of La Niña conditions persisting over the
coming season, and 45 – 50 % chance of a return to ENSO-
neutral conditions.
Tropical Cyclone Activity and Guidance
T
ropical cyclone Hettie, the first to form in the southwest Pacific during the 2008–09 season, developed on 28th January to
the southeast of Fiji. The system brought southerly winds and heavy rain to the central region of Fiji on the 28–29 January,
and then tracked to the southwest before dissapating on 30 January. Conditions in the tropical Pacific are still likely to affect
the chances of tropical cyclone (TC) activity for several countries between January and May 2009. There is an increased risk
of TC occurrence for countries west of the Date Line, including Vanuatu, the Solomon Islands, and New Zealand, and a slight
risk increase for New Caledonia. Reduced risk is expected for Samoa, Tonga, and Niue.
The Island Climate Update, No. 101, February 2009
Page 4
Tropical Pacific rainfall – January 2009
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
January 2009
rainfall
total (mm)
January 2009
percent of
average
Australia
Cairns Airport
882
223
Townsville Airport
664
245
Brisbane Airport
77
49
Sydney Airport
25
25
Cook Islands
Penrhyn
28
11
Aitutaki
221
86
Rarotonga Airport
137
61
Fiji
Rotuma Island
500
141
Udu Point
700
224
Nadi Airport
1181
344
Nausori
652
179
French Polynesia
Hiva Hoa, Atuona
34
22
Bora Bora
201
81
Tahiti – Faa’a
261
96
Tuamotu, Takaroa
123
64
Gambier, Rikitea
433
297
Tubuai
67
33
Rapa
110
46
Kiribati
Tarawa
N/A
N/A
Kanton
N/A
N/A
New Zealand
Kaitaia
20
12
Whangarei Airport
12
14
Auckland Airport
32
48
New Caledonia
Ile Art, Belep
60
25
Koumac
96
54
Ouloup
72
41
Ouanaham
85
43
Poindimie
235
63
La Roche
215
122
La Tontouta
77
64
Noumea
75
65
Moue
150
81
Territory and
station station
name
January 2009
rainfall
total (mm)
January 2009
percent of
average
Niue
Hanan Airport
388
114
Liku
255
103
North Tasman
Lord Howe Island
46
40
Norfolk Island
64
70
Raoul Island
19
15
Samoa
Faleolo Airport
302
123
Apia
386
79
Nafanua
607
123
Afiamalu
955
120
Maota
207
50
Solomon Islands
Taro
240
100
Munda
401
104
Auki
435
121
Honiara
509
187
Henderson
406
171
Kira Kira
377
110
Santa Cruz, Lata
491
117
Tonga
Niuafo’ou
N/A
N/A
Mata’aho Airport
326
118
Lupepau’u
392
136
Salote Airport
559
341
Nuku’alofa
346
199
Fua’amotu Airport
570
284
Tuvalu
Nanumea
4
1
Nui Island
96
23
Funafuti
445
115
Nuilakita
337.0
90
Vanuatu
Sola
557
141
Pekoa
539
166
Lamap
340
135
Port Vila
420
152
Tanna/Whitegrass
79
N/A
Aneityum
183
66
The Island Climate Update, No. 101, February 2009
Page 5
Rainfall outlook map for February to April 2009
Tropical rainfall and SST outlook: February to April 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 February–April 2009 forecast period, a
region of suppressed convection is likely to encompass
the central and eastern Southwest Pacific, extending to
the southeast from Western Kiribati and including Tuvalu,
Tokelau, the Northern Cook Islands, and the Society Islands,
where below normal rainfall is expected. Near–to–below
normal rainfall is expected for Samoa, Eastern Kiribati, the
Tuamotu archipelago, and the Marquesas Islands.
Enhanced convection is expected to extend southeast from,
Papua New Guinea, and includes New Caledonia, Tonga
and Niue, where above normal rainfall is forecast. Near or
above normal rainfall is forecast for the Austral Islands, Fiji,
the Southern Cook Islands, and Pitcairn Island. No clear
precipitation guidance is offered for the Solomon Islands or
Wallis & Futuna for the three-month forecast period.
SSTs are expected to be above normal around eastern
Papua New Guinea, and surrounding Vanuatu, Fiji and
New Caledonia. Near normal or above normal SSTs are also
expected for Niue, Tonga, Wallis & Futuna, the Southern
Cook Islands, the Society Islands, Austral Islands, and
Pitcairn Island. Near normal or below normal SSTs are
forecast for the Tuamotu archipelago, the Northern Cook
Islands, Tuvalu, Tokelau, and Eastern & 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 February is 63%, 1% lower than the long-
term average for all months combined. The SST forecast
confidence is moderate–to–high for this period.
Island Group
Rainfall Outlook
Outlook confidence
New Caledonia
20:30:50 (Above)
High
Niue
20:35:45 (Above)
Moderate-High
Papua New Guinea
20:35:45 (Above)
Moderate-High
Tonga
20:35:45 (Above)
Moderate-High
Austral Islands
25:35:40 (Near or Above)
Moderate-High
Cook Islands (Southern)
25:35:40 (Near or Above)
Moderate-High
Fiji
25:35:40 (Near or Above)
Moderate-High
Pitcairn Island
25:35:40 (Near or Above)
Moderate-High
Vanuatu
25:35:40 (Near or Above)
Moderate-High
Solomon Islands
30:35:35 (Climatology)
Moderate-High
Wallis & Futuna
30:35:35 (Climatology)
Moderate
Marquesas
35:40:25 (Near or Below)
Moderate-High
Kiribati (Eastern)
40:35:25 (Near or Below)
Moderate-High
Samoa
40:35:25 (Near or Below)
Moderate-High
Tuamotu Islands
40:35:25 (Near or Below)
Moderate-High
Cook Islands (Northern)
45:35:20 (Below)
Moderate-High
Society Islands
45:35:20 (Below)
Moderate-High
Kiribati (Western)
50:30:20 (Below)
Moderate-High
Tokelau
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
SST outlook map for February to April 2009
Island Group
SST Outlook
Outlook confidence
Fiji
20:35:45 (Above)
Moderate-High
New Caledonia
20:35:45 (Above)
Moderate-High
Papua New Guinea
20:35:45 (Above)
Moderate-High
Vanuatu
20:35:45 (Above)
Moderate-High
Austral Islands
25:35:40 (Near or above)
Moderate
Cook Islands (Southern)
25:35:40 (Near or above)
Moderate
Niue
25:35:40 (Near or above)
Moderate-High
Pitcairn Island
25:35:40 (Near or above)
Moderate
Society Islands
25:35:40 (Near or above)
Moderate-High
Tonga
25:35:40 (Near or above)
Moderate-High
Wallis & Futuna
25:35:40 (Near or above)
Moderate-High
Samoa
25:40:35 (Near or above)
Moderate
Marquesas
30:40:30 (Near Normal)
Moderate
Solomon Islands
30:40:30 (Near Normal)
Moderate
Tuvalu
35:35:30 (Climatology)
Moderate-High
Cook Islands (Northern)
35:40:25 (Near or Below)
Moderate-High
Tokelau
35:40:25 (Near or Below)
Moderate-High
Tuamotu Islands
35:40:25 (Near or Below)
Moderate
Kiribati (Eastern)
40:35:25 (Near or Below)
Moderate-High
Kiribati (Western)
40:35:25 (Near or Below)
Moderate-High
Australia
NewZealand
Fiji
NewCaledonia
Vanuatu
Solomon Is
Pitcairn
Samoa
Tonga
Niue
E Kiribati
Papua NewGuinea
NCook Is
S Cook Is
Society Is
WKiribati
Line Is
Tuvalu
Marquesas Is
Austral Is
Marshall Is
Rawaki Is
Tokelau Is
Nauru
Fed States of Micronesia
Tuamotu Is
EQUATOR
Wallis &Futuna
Near
Normal
Below normal
Near or below
Near or above
Above normal
The Island Climate Update, No. 101, February 2009
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:
Dr Andrew Lorrey, NIWA,
41 Market Place, Auckland, New Zealand
E-mail:
a.lorrey@niwa.co.nz
Forecasts:
Dr. Andrew Lorrey (South Pacific rainfall and SST forecasts) 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.
Extreme rainfall and new records in the Fiji Islands, January 2009
Fiji Meteorological Service
J
anuary 2009 was the wettest first month of the year in more than
a century at several locations in Fiji. The total monthly rainfall
was equivalent to or above 200% of normal at more than 75% of
reporting stations in the Western, Central and Eastern Divisions
of the country. Fourteen monthly rainfall totals and seven
24hr daily rainfall records were broken during the month. The
considerable amount of rainfall was due to a number of intense
synoptic scale weather features that impacted the Fiji region,
including an active monsoonal trough, an enhanced South
Pacific Convergence Zone (SPCZ), two Tropical Depressions,
and Tropical Cyclone (TC) Hettie.
The hovering of the monsoonal trough and SPCZ over Fiji during
the early to middle part of January resulted in severe flooding
that claimed 12 lives and caused major damage in many parts
of Viti Levu and Vanua Levu. Many roads and bridges including
the Sigatoka old bridge were destroyed. There was significant
damage to agricultural crops along the major floodplains. Ba,
Nadi, and parts of Sigatoka town were flooded. In the case of
Ba and Nadi, flooding was the worst in over 75 years. School
facilities and homes in these areas were without water and
electricity for several days due to broken water pipes. As of 30
January, the flood related damage cost is F$76.1M.
A flooded house in Nadi, Fiji that resulted from high rainfall
during January 2009.
The January 2009 floods are the worst natural disaster
‘economically’ to affect Viti Levu since the drought of 1998.
The title of ‘worst natural disaster’ should probably continue to
apply to the TC(s) and flooding in late February 1931 when
The Island
Climate Update
A badly damaged bridge in Nadi, Fiji
flooding similar in magnitude to the 2009 event (but including
the Rewa River) claimed more than 200 lives. There were
statements in the media soon after the recent flood that the
2009 event was higher than the 1931, 8.37 m above mean sea
level record at the Rarawai Mill.
Highlights of the month include:
•Seven sites receiving more than 200 mm rainfall in
24 hours
•A daily rainfall total of 378 mm on the 13th at
Nabouwalu, breaking the record from 1932
•Fourteen stations recording more than 700 mm
rainfall
•Seven sites receiving more than 1m of rainfall
•A total monthly rainfall of 1545.1 mm recorded at
Monasvu, the highest since records began there in
1980
A complete accounting of the month’s events, climate statistics,
an explanation of the cause of the January flooding, and
photographs from across Fiji of the flood damage can be found
on the Fiji Meteorological Services website (www.met.gov.fj/
index.php).
Further enquiries about the floods can also be directed to the
Fiji Meteorological Services by emailing climate@met.gov.fj.