SEASONAL CLIMATE SEASONAL CLIMATE FORECASTING TO BENEFIT FORECASTING TO BENEFIT BUSINESS AND SOCIETY BUSINESS AND SOCIETY Dr Mark Saunders Dr Mark Saunders Head of Seasonal Forecasting Head of Seasonal Forecasting Department of Space and Climate Physics Department of Space and Climate Physics University College London University College London UCL Lunch Hour Lecture UCL Lunch Hour Lecture 13th November 2001 13th November 2001
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BUSINESS AND SOCIETY SEASONAL CLIMATE · UCL Lunch Hour Lecture 13th November 2001. 2 University Department Department of Space and ... Seasonal Weather Prediction ... CRU NAO Index
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SEASONAL CLIMATESEASONAL CLIMATEFORECASTING TO BENEFITFORECASTING TO BENEFIT
BUSINESS AND SOCIETYBUSINESS AND SOCIETY
Dr Mark SaundersDr Mark Saunders
Head of Seasonal ForecastingHead of Seasonal ForecastingDepartment of Space and Climate PhysicsDepartment of Space and Climate Physics
University College LondonUniversity College London
UCL Lunch Hour LectureUCL Lunch Hour Lecture13th November 200113th November 2001
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University DepartmentUniversity Department
Department of Space andDepartment of Space and Climate Physics Climate PhysicsUniversity College LondonUniversity College LondonHOLMBURY ST MARYHOLMBURY ST MARYDorkingDorkingSurrey RH5 6NTSurrey RH5 6NTUKUK
Limits of Weather PredictionLimits of Weather Prediction
““Claims of Claims of skilfullskilfull predictions of day-to-day predictions of day-to-dayweather beyond 1-2 weeks have no scientificweather beyond 1-2 weeks have no scientificbasis and are either misinformed or calculatedbasis and are either misinformed or calculatedmisrepresentations of true capabilitiesmisrepresentations of true capabilities””..
American Meteorological Society PolicyAmerican Meteorological Society PolicyStatement, 2001Statement, 2001
�� The prediction of anomalies in climate overThe prediction of anomalies in climate overseasonal (1-3 months) periods of time.seasonal (1-3 months) periods of time.
�� Skill possible because atmosphere is forcedSkill possible because atmosphere is forcedby large scale (and predictable) anomalies inby large scale (and predictable) anomalies insea surface temperature which evolve slowly.sea surface temperature which evolve slowly.
�� A major focus of MSSL Climate PhysicsA major focus of MSSL Climate PhysicsResearch:Research:
England and Wales WinterEngland and Wales WinterRainfall 1900/01-2000/01Rainfall 1900/01-2000/01
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Central England WinterCentral England WinterTemperature 1900/01-2000/01Temperature 1900/01-2000/01
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2. 2. Impacts of SeasonalImpacts of SeasonalWeather on BusinessWeather on Businessand Societyand Society
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Industries AffectedIndustries Affected
•• Anomalous seasonal weather affects theAnomalous seasonal weather affects thefinancial performance of financial performance of 70%70% of business of businessand industry. Sectors affected include:and industry. Sectors affected include:
Insurance, power, construction, farming,Insurance, power, construction, farming,tourism, retail, manufacturing and travel.tourism, retail, manufacturing and travel.
•• Anomalous weather also affects our Anomalous weather also affects our healthhealth..
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Atlantic HurricanesAtlantic Hurricanes
�� Rank as theRank as thelargest cause oflargest cause ofUS catastropheUS catastropheloss (loss (££3.5 3.5 bnbn per peryear 1925-2000)year 1925-2000)
�� Floyd (pictured)Floyd (pictured)had a damage billhad a damage billof of ££3.3 billion.3.3 billion.
NOAA-14 AVHRR Satellite ImageNOAA-14 AVHRR Satellite Image15 September 199915 September 1999
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European Winter StormsEuropean Winter Storms
Porthleven, Cornwall: 4 Jan 1998 (Courtesy, Simon Burt)
�� European windstormsEuropean windstormscaused damages of caused damages of ££1.91.9bn bn per year 1990-1999per year 1990-1999
�� Rank as the 2nd highestRank as the 2nd highestcause of global insuredcause of global insuredlosses after US hurricaneslosses after US hurricanes
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UK Winter TemperatureUK Winter Temperature
For each For each 11ooCCthe mean dailythe mean dailytemperature fortemperature forEngland andEngland andWales Wales dropsdropsbelow 18below 18°°CC the theNational GridNational Gridsuppliessupplies££200,000200,000 worth worthof additionalof additionalpower.power.
Scarborough: 9/2/1991 (Image courtesy of Scarborough: 9/2/1991 (Image courtesy of ““PAPA”” News). News).
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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Cumulative Probability
Ave
rage
Vol
ume
per
Day
1999 Dry MW1999 Dry WE1999 Wet MW1999 Wet WE
Dry Weekend
Dry Weekday
Wet Weekend
Wet Weekday
England and Wales RainfallEngland and Wales RainfallImpact on Car Wash SalesImpact on Car Wash Sales
(Figure Courtesy of Lance (Figure Courtesy of Lance GarrardGarrard, , MetRiskMetRisk))
Statistical principal component analysis of modesStatistical principal component analysis of modesof sea surface temperature variability.of sea surface temperature variability.
‘‘TrueTrue’’ hindcasthindcast skill for 1986-2000 assessed by skill for 1986-2000 assessed by constructing models always with constructing models always with prior prior data.data.
Leads from 0 to 12 months examinedLeads from 0 to 12 months examined..
Skill Score and UncertaintySkill Score and Uncertainty
Employ percentage improvement in RMSE over a Employ percentage improvement in RMSE over a climatologicalclimatological forecast ( forecast (SSSSClimClim (%) (%)):):
SS SSClimClim = (1 - = (1 - RMSERMSEForeFore//RMSERMSEClimClim) x 100) x 100
Compute 95% confidence intervals on skill using Compute 95% confidence intervals on skill using the bootstrap method.the bootstrap method.
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ENSO Forecast Skill for ASENSO Forecast Skill for AS
2020
La La NiNiññaa Impacts Impacts
(Image Courtesy, NOAA) (Image Courtesy, NOAA)
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Tropical North Atlantic ForecastTropical North Atlantic ForecastSkill for ASSkill for AS
Seasonal Typhoon ActivitySeasonal Typhoon ActivitySkill Skill vs vs Lead TimeLead Time
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"Seasonal Prediction of Tropical Cyclones""Seasonal Prediction of Tropical Cyclones"•• Three ocean basinsThree ocean basins•• New statistical and dynamicalNew statistical and dynamical
model techniquesmodel techniques•• Land-falling tropical cyclonesLand-falling tropical cyclones•• Useful lead timeUseful lead time•• Increase skill levelIncrease skill level•• Frequency and severityFrequency and severity•• Spatial resultsSpatial results
CRU NAO Index = 0.7 +/- 1.0CRU NAO Index = 0.7 +/- 1.0
Thus the coming winter is expected to be a Thus the coming winter is expected to be a neutralneutralNAO winterNAO winter with temperature and rainfall close to the with temperature and rainfall close to thelast 10-year average.last 10-year average.
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ConclusionsConclusions
�� Seasonal climate prediction is an Seasonal climate prediction is an innovationinnovationin meteorology.in meteorology.
�� Forecast skill is already significant at leads ofForecast skill is already significant at leads ofa few months.a few months.
�� There are sound grounds for expecting thisThere are sound grounds for expecting thisskill will improveskill will improve with further research. with further research.
�� With the earnings of With the earnings of 70% of industry70% of industry sensitive sensitiveto seasonal weather, business executives willto seasonal weather, business executives willbe well advised to monitor developments inbe well advised to monitor developments inseasonal forecasting over the next few years.seasonal forecasting over the next few years.