Scientific benefits from undertaking Scientific benefits from undertaking data rescue activities: some data rescue activities: some

examples of what can be achieved examples of what can be achieved with long recordswith long records

Phil JonesPhil JonesClimatic Research UnitClimatic Research Unit

University of East AngliaUniversity of East AngliaNorwich, UKNorwich, UK

Summary of scientific benefitsSummary of scientific benefits

• Longer records for analysis and assessment of Longer records for analysis and assessment of trendstrends

• Able to place recent records in a much longer Able to place recent records in a much longer contextcontext

• Provide longer records for assessing impacts of Provide longer records for assessing impacts of climate changeclimate change

• Provide longer records for the calibration of natural Provide longer records for the calibration of natural and documentary proxiesand documentary proxies

• Provide longer records for ReanalysisProvide longer records for Reanalysis** extensions extensions further back in timefurther back in time

• Ensures NMSs are aware of early data in their Ensures NMSs are aware of early data in their country and their possible shortcomingscountry and their possible shortcomings

*model-based assimilation of the past – so internally consistent

Placing in a longer contextPlacing in a longer context

• Some long European recordsSome long European records

• European summer of 2003European summer of 2003

• Central England temperature Central England temperature extremes since 1772 extremes since 1772

Long European regional temperaturesLong European regional temperatures

Extreme Heat WaveSummer 2003Europe:

Heat waves in Central Europe (35-50ºN, 0-20ºE) in JJA

Trend plus variability?Max temps in Basle (1961-90 and 2003)

Counts of daily Counts of daily temperature temperature extremes in the extremes in the CET SeriesCET Series

Defined as > 90%ile (warm) and < 10%ile (cold) – relative to the period 1881-1910 and to the time of year

Annual number of warm days/cold days

Could have used 1961-90 as the base period. Changing the base period just changes the level

Longer records for assessment Longer records for assessment of proxy evidenceof proxy evidence

• Documentary Records (N. Sweden – where Documentary Records (N. Sweden – where the instrumental record has been extended the instrumental record has been extended back from the 1860s to 1800, back from the 1860s to 1800, Klingbjer and Moberg, Klingbjer and Moberg,

20032003))

• Natural Proxy Records (N. Fennoscandian Natural Proxy Records (N. Fennoscandian trees and Greenland examples – the latter trees and Greenland examples – the latter extending the instrumental record from the extending the instrumental record from the 1870s to the 1780s)1870s to the 1780s)

• Both extend the instrumental record beyond Both extend the instrumental record beyond that readily available from the local NMSthat readily available from the local NMS

Klingbjer and Moberg (2003) Int. J. Climatol. 23, 1465-1494.

N. Fennoscandia (Haparanda, Klingbjer and Moberg, 2003) N. Fennoscandia (Haparanda, Klingbjer and Moberg, 2003) Comparison of instrumental, documentary and natural proxy Comparison of instrumental, documentary and natural proxy datadata

SW Greenland temperaturesSW Greenland temperatures

Seasonal temperatures for SW Seasonal temperatures for SW GreenlandGreenland

From Vinther et al (2006) JGR

Running correlations (30-year window) Running correlations (30-year window) between Greenland ice cores (winter oxygen between Greenland ice cores (winter oxygen isotope values) and SW Greenland winter isotope values) and SW Greenland winter temperaturestemperatures

Assessment of changes in Assessment of changes in extremesextremes

• Require long series of daily data Require long series of daily data (earlier CET example)(earlier CET example)

• Consistent measures of extremesConsistent measures of extremes

• Extremes are how the public and Extremes are how the public and governments perceive climate governments perceive climate changechange

10th (left) and 90th (right) percentiles

Frequency of occurrence of cold or warm temperatures for 202 global stations with at least 80% complete data between 1901 and 2003 for 3 time periods: 1901 to 1950 (black), 1951 to 1978 (green) and 1979 to 2003 (orange).

1979-2003

1951-1978

1901-1950

Warm nights are increasing; cold nights decreasing

fewer more fewer more

Longer records to look at the influence Longer records to look at the influence of the circulation on surface of the circulation on surface temperature and precipitation seriestemperature and precipitation series

• Paris – daily pressure (MSLP) data Paris – daily pressure (MSLP) data can be digitized back to 1670s with can be digitized back to 1670s with only a few missing yearsonly a few missing years

• London – back to the 1690sLondon – back to the 1690s

• Together these two sites produce a Together these two sites produce a useful winter measure of westerly useful winter measure of westerly flow (Paris minus London ≈ NAO)flow (Paris minus London ≈ NAO)

The Royal Society's The Royal Society's Meteorological Record Meteorological Record (1774 - 1842) - London(1774 - 1842) - London

• Appendix to Phil.Trans Appendix to Phil.Trans publicationpublication

• Twice daily observations Twice daily observations

• Very nearly complete, but Very nearly complete, but gap from 1782 - 1786gap from 1782 - 1786

• Extracted Extracted Internal/External Internal/External Temperature & PressureTemperature & Pressure

[SOURCE: Philosophical Transactions of the Royal Society of London, 1775]

James Jurin's James Jurin's Weather Diary Weather Diary (1728 - 1750) - (1728 - 1750) - LondonLondon

•Once daily Once daily observation of observation of temperature, temperature, pressure & wind pressure & wind directiondirection

•Observation time Observation time includedincluded

Joseph de L'Isle's Joseph de L'Isle's Weather Diary (1747 Weather Diary (1747 - 1760) - Paris- 1760) - Paris

• Three or four Three or four observations per dayobservations per day

• Temperature, Temperature, pressure, state of the pressure, state of the skysky

• Mostly readings from Mostly readings from 2+ barometers2+ barometers

• Temperature scale Temperature scale problematicproblematic

Running 30-year correlation between Running 30-year correlation between winter Paris minus London Pressure winter Paris minus London Pressure Index and several temperature series Index and several temperature series and one precipitation seriesand one precipitation series

From Jones et al. (2003) in AGU book on the NAO by Hurrell et al.

Correlations generally consistent except for England and Wales precipitation and NH temperatures north of 20ºN

ConclusionsConclusions

• Longer records than currently available to Longer records than currently available to each NMS are generally available across each NMS are generally available across Europe and the MediterraneanEurope and the Mediterranean

• Records need finding, digitizing and then Records need finding, digitizing and then assessing for homogeneityassessing for homogeneity

• Records often located in libraries/archives, Records often located in libraries/archives, sometimes in other countries. They may sometimes in other countries. They may take some finding, but they generally existtake some finding, but they generally exist