national climate and water briefing...july-september 2010 july-september 2011 month to date: october...
TRANSCRIPT
Lake Eyre - © Pete Dobre
National Climate and Water Briefing
October 2011
Lake Eyre - © Pete Dobre
Climate conditions and outlook
• Recent climate conditions and trends • Current state of key climate drivers • Climate outlook
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Calculating deciles
Sort and rank
Historical record Sorted historical record
Group into tenths for deciles
Deciles 1 to 10
1 2 3 4 5 6 7 8 9 10
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A tale of two years: rainfall
July – September 2010 July – September 2011 Month to Date: 20 October
Wettest on record Rank 45 of 112 years
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A tale of two years: upper layer soil moisture
September2011September2010
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A tale of two years: lower layer soil moisture
September2010 September2011
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A tale of two years: maximum temperature
July-September 2010 July-September 2011 Month to Date: October
10th coolest on record 8th warmest on record
Recent rainfall trends: the global picture Thailandflooding2011
Tuvaludrought2011
h8p://www.cpc.ncep.noaa.gov/products/fews/AFR_CLIM/afr_clim_season.shtml
SOMALIAKENYA
ETHIOPIA
EastAfricandrought2011
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Recent rainfall trends: the global picture
Typical La Nina Summer Impacts
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Key points
1. Australian spring of 2011 has been vastly different to that of 2010
2. Effects of the La Niña from last year and emerging event this year are being felt around the world
bom.gov.au/climate/ahead
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Climate conditions and outlook
• Recent climate conditions and trends • Current state of climate drivers • Climate outlook
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La Niña – the return
Sea surface temperature difference from average Southern Oscillation Index
2010
2011
La Niña
- 8 ▼
+8 ▲
El Niño
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A tale of two years: change in the Indian Ocean
2010
+IOD
-0.4 ▼
+0.4 ▲
-IOD
2011
DifferencebetweenSeptember2011&September2010OceanTemperatures
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• September2010:warmwatertothenorthofAustralia(2010–recordwarmAustralianoceantemperatures)• September2011:averagetocoolwatertothenorthofAustralia
A tale of two years: Australian sea surface temperatures
September2010 September2011 Weekending16October2011
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Key points
1. A late forming La Niña is developing in the tropical Pacific 2. Current observations are clearly different to this time last year 4. Expect warming in the Indian Ocean with start of Monsoon 3. Deep soil moisture is still high from summer rainfall while top
layers have dried
bom.gov.au/climate/ahead
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Climate conditions and outlook
• Recent climate conditions • Current state of key climate drivers • Climate outlook
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Pacific Ocean – forecast
• La Niña conditions forecast by most models • Event has started late in the
year • Current conditions indicate a
weaker event than in 2010-11
Australia’sPOAMAmodelforecastforNINO3.4
bom.gov.au/climate/enso
El Niño
- 0.8 ▼
+0.8 ▲
La Niña
El Niño
La Niña
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Rainfall outlook for November 2011 to January 2012 bom.gov.au/climate/ahead
Seasonal outlook for November 2011 – January 2012 Global model outlooks POAMA outlook for Nov -Jan
20102011
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Temperature outlook for November to January
• Warm days in the north and south, cool days on the QLD/NSW border
• Warm nights over most of southern and eastern Australia
Minimum temperature Maximum temperature
Percentage chance of above median
Percentage chance of above median
Tropical cyclone outlook: November 2011- April 2012 • Above average tropical
cyclones forecast in Australian region and western region of South Pacific
• Below average tropical
cyclones forecast for eastern region of South Pacific
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Key points
1. La Niña developing in Pacific – indicators much weaker than at this point in 2010 2. Rainfall inland including Murray-Darling Basin less than normal 3. Outlook for wetter conditions in east of Australia 4. Tropical Cyclone forecast for above average number of cyclones in the Australian
region
bom.gov.au/climate/ahead
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Hydrologic conditions and outlook
• Trends in water storage and rainfall • Conditions in Murray-Darling Basin • Forecasts for the next three months • New forecast locations
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Water storage levels – current status
water.bom.gov.au
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Lake Eildon reaching 100%
Image:TheAge
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Water supply storages rising
Thomson Dam (water supply for Melbourne) Warragamba Dam (water supply for Sydney)
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Northern Australia storages
Argyle Dam (Ord River in Western Australia) Burdekin Dam (Burdekin River in Queensland)
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Drier winters and wetter summers?
Winter and summer rainfall trends over the last 30 years 1981-2010
Example products available in the Australian Water Resources Assessment 2010 ([email protected])
Australian Water Resources Assessment 2010 (released
inNovember)
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Hydrologic conditions and outlook
• Trends in water storage and rainfall • Conditions in Murray-Darling Basin • Forecasts for the next three months • New forecast locations
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Most significant September rainfall at end of the month
One month rainfall deciles for September 2011 Total rainfall recorded in the week to 9.00 am on 1 October
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Low September streamflows
One month observed streamflow terciles for September Three month observed streamflow terciles for July to September
High flowNear median flowLow flow
High flowNear median flowLow flow
South-east Murray-DarlingSeasonal Streamflow Observationsfor July to September 2011
High flowNear median flowLow flow
High flowNear median flowLow flow
South-east Murray-Darling Monthly Streamflow Observationsfor September 2011
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Drying in lower layer soil moisture
June 2010 lower layer soil moisture September 2011 lower layer soil moisture March 2011 lower layer soil moisture
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Hydrologic conditions and outlook
• Trends in water storage and rainfall • Conditions in Murray-Darling Basin • Forecasts for the next three months • New forecast locations
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How have the forecasts been going ?
July to September • mostly moderate skill • 14 hits, seven misses • all misses were by one tercile
South-east Murray-Darling Seasonal Streamflow Forecastsfor July to September 2011
What is a tercile hit ?
A tercile hit is when the observed streamflow for the forecast period is in the same tercile as the most likely tercile from the forecast pie chart
Most likely tercile
Forecast as tercile pie chart
Low flow
Near median flow
High flow
Sorted Historical Streamflow Record
Observed streamflow
Low flow
Near median flow
High flow
Rank/Year
Str
eam
flo
w
July to September forecasts
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Low to near median flows most likely
• October to December forecast – low flows more likely for the
western catchments – near median flows are more
likely in eastern catchments – moderate to high skill at most
sites
Forecast confidence
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Hydrologic conditions and outlook
• Trends in water storage and rainfall • Conditions in Murray-Darling Basin • Forecasts for the next three months • New forecast locations
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New forecast sites
• Initial investigations on sites in every state and territory • Seasonal forecasting data needs – quality, length of record, available in real time
• High Quality Streamflow Reference Stations – basis for further site selection
– comprehensive stakeholder engagement and site selection
Potential Sites
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New forecast sites
• 25 new locations added – Richmond, Shoalhaven, Upper Murray, Manning, Murrumbidgee, Lachlan, Gwydir and Macquarie basins
• Less skill than current sites • Available on password protected experimental
website
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Station Name Drainage Division River Basin Richmond River at Wiangaree South-East Coast Richmond Nowendoc River at Rocks Crossing South-East Coast Manning Shoalhaven River at Warri South-East Coast Shoalhaven Tambo River at Swifts Creek South-East Coast Tambo Wonnangatta River at Waterford South-East Coast Mitchell Latrobe River at Willow Grove South-East Coast Latrobe Maragle Creek at Maragle Murray-Darling Upper Murray Jingellic Creek at Jingellic Murray-Darling Upper Murray Snowy Creek at below Granite Flat Murray-Darling Upper Murray Tarcutta Creek at Old Borambola Murray-Darling Murrumbidgee Halls Creek at Bingara Murray-Darling Gwydir Abercrombie River at Abercrombie Murray-Darling Lachlan Boorowa River at Prossers Crossing Murray-Darling Lachlan Ovens River at Bright Murray-Darling Ovens Fifteen Mile Creek at Greta South Murray-Darling Ovens
New public sites in November
Tour of experimental forecast sites
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Key points 1. Lake Eildon reaching 100%, spilling for first time since 1996 2. Increasing storage levels in Perth, Melbourne and Sydney 3. Forecast for southeast Murray-Darling – low flows more likely for western catchments – near median flows more likely for eastern catchments – moderate to high forecast confidence
4. Australian Water Resources Assessment 2010 and forecasts for 15 new locations in November
bom.gov.au/water/ssf
Lake Eyre - © Pete Dobre