© Crown copyright Met Office © Crown copyright Met Office Vicky Pope October 2013 Latest developments in climate modelling:
© Crown copyright Met Office © Crown copyright Met Office
Vicky Pope
October 2013
Latest developments in climate modelling:
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Seamless prediction
Forecast lead-time
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boundary
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Analysis of past weather observations to manage climate risks
Eg. Agriculture: this informs crop choice and planting date to optimise yields and minimise crop failure risk. Predicting routine and
hazardous weather conditions and disseminating tailored and timely warnings.
Public, emergency response, international disaster risk reduction
Monthly to decadal predictions informs probability of drought, cold, heat.
Contingency planners, national and international humanitarian response, government and private infrastructure investment
Global and regional climate predictions.
Informs mitigation policy and adaptation choices. Impacts on water resurces, heat stress, crops, infrastructure.
Supporting decision making
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The big picture:
Models for global climate change and
mitigation
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Climate models Used in IPCC AR4 2007
People Emissions Atmospheric
Composition
Climate
Change
Impacts
Climate models Integrated Assessment Models Impact models
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People Emissions Atmospheric
Composition
Climate
Change
Impacts
Feedbacks
Earth System Models Used by some in IPCC AR5 2013
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The global carbon cycle...
Why is it so important?
© Crown copyright 2007
Vegetation absorbs and releases carbon
• “photosynthesis” absorbs CO2 from the atmosphere, and turns it into carbon in the living vegetation
CO2
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Vegetation absorbs and releases carbon
• “photosynthesis” absorbs CO2 from the atmosphere, and turns it into carbon in the living vegetation
• The plant’s metabolism releases some back to the atmosphere
• “plant respiration”
CO2 CO2
© Crown copyright 2007
Vegetation absorbs and releases carbon
• “photosynthesis” absorbs CO2 from the atmosphere, and turns it into carbon in the living vegetation
• The plant’s metabolism releases some back to the atmosphere
• “plant respiration”
• Dead matter (leaves etc) falls to soil
• LARGE amounts of carbon stored in the soil
CO2 CO2
“litter”
© Crown copyright 2007
Vegetation absorbs and releases carbon
• “photosynthesis” absorbs CO2 from the atmosphere, and turns it into carbon in the living vegetation
• The plant’s metabolism releases some back to the atmosphere
• “plant respiration”
• Dead matter (leaves etc) falls to soil
• LARGE amounts of carbon stored in the soil
• Decomposed by bacteria/microbes and released as CO2 back to the atmosphere
• “soil respiration”
CO2 CO2
“litter” CO2
© Crown copyright 2007
Large scale view
• Very large amounts of carbon in…
• Very large amounts of carbon out
• In long term, these balance
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Ocean carbon cycle
• Also absorbs carbon
• Sea water dissolves carbon
• Plankton photosynthesise and/or eat each other
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Ocean carbon cycle
• Large amounts of CO2 in
• And out
• In long term, these balance
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Carbon cycle “protection”
• Currently, the global carbon cycle absorbs about half of our emissions
CO2 growth in the atmosphere
CO2 emissions
© Crown copyright 2007
Carbon cycle “protection”
• Currently, the global carbon cycle absorbs about half of our emissions
CO2 growth in the atmosphere
CO2 emissions
Warm years mean more CO2
Balancing the carbon
100
What we emit…
Balancing the carbon
100
50
25 25
=
atmosphere land ocean
What we emit… Must go somewhere
Balancing the carbon
100
50
25 25
=
atmosphere land ocean
If these go down due to climate change…
What we emit… Must go somewhere
Balancing the carbon
100
50
25 25
=
atmosphere land ocean
If these go down due to climate change…
This must go up
What we emit… Must go somewhere
Balancing the carbon
100
50
=
atmosphere
For given emissions, carbon cycle feedback means:
- More CO2 stays in atmosphere
- We will see greater climate change >50
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The local picture:
Models for regional detail and adaptation
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“I need hardly repeat, Sir, what has been so often explained, that the ‘forecasts’ are expressions of probabilities – and not dogmatic predictions.”
Admiral Robert Fitzroy, 1863
“… one flap of a sea-gull’s wing may forever change the future course of the weather”
Edward Lorenz, 1963
10-year Vision: Integrated weather and climate prediction
for estimating hazards and risks
A number of global predictions at ~20km with
lead times of days to years:
Large-scale weather
A smaller number of regional predictions at
~1km:
Local weather
Probability of local hazard:
Impacts
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Moving from uncertainty to probabilities/likelihoods
UKCIP02
Single projection
Very unlikely to be less than (10%)
UKCP09
Central estimate (50%)
Very unlikely to be more than (90%)
Su
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Ra
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08
0’s
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Significant step forwards:
• First to quantify uncertainties and provide probability
distribution functions
• First to include feedbacks and uncertainties from
carbon cycle
But……
• No wind or snow variables, only limited information on
extremes – but more could be extracted from the
regional climate model ensembles
• No account of the current state of the climate system
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UKCP09: The first step on a long road...
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Storm-resolving forecasts: 1800 5th – 1500 6th Sep 2008
© Crown copyright Met Office Frames at 10min intervals
Our 3 day forecasts are as good as our 1 day forecasts were 20 years ago.
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Improved rainfall over and around mountains and hills in 1.5km forecast model
12 km
4 km 1 km
Rain gauge observations and model forecasts
Model orography
12km 1 km
Case study: Carlisle flood, Jan 2005
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Future change in the 1.5km model
• First climate change experiments with a
convection-permitting have now been
completed
• For first time we can examine future changes in
heavy rainfall at the hourly timescale
• 1.5km model shows large increases in heavy rain
in summer, which is very different to the driving
12km model.
• 12km RCM underestimates heavy rain in
summer, and shows little change in the future.
• Both models show similar increases in heavy rain
in winter.
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Exploitation of the 1.5km model results
1.5km model results
Water How will flooding, water resources...
Change?
Storms How will small-scale intense (convective) storms change?
Extremes How will the risk of
risk of extreme events change?
Accuracy What are the strengths
and weaknesses of current models?
Improvement How can models be improved?
© Crown copyright Met Office
Exploitation of the 1.5km model results
1.5km model results
Water How will flooding, water resources...
Change?
Storms How will small-scale intense (convective) storms change?
Extremes How will the risk of
risk of extreme events change?
Accuracy What are the strengths
and weaknesses of current models?
Improvement How can models be improved?
What else? What would help
you?
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Questions?