Comments on “Review of UK Climate Change Indicators” – from Hadley Centre

 

General

·        The review includes and proposes rather too many short-period indicators.  Climate change is a long timescale phenomenon.  This means that recent change needs to be put into the context of, at least, a 50 to 100 year record.

·        Avoid indicators only weakly related to climate change, and more strongly by other factors (as this can mislead).  A good example is surface ozone, where we will never see the 276ppb reached in 1976, as the precursor pollutants are much reduced now.  “Public resonance” isn’t a very scientific reason for keeping things in which are only marginally correlated with climate, unless the other factors can be backed out (e.g. in the case of ozone, presumably we could model out the changing precursor emissions)?

 

CET

·        Daily record exists back to late 18th century.

·        Possible to compute long record of degree-days and other temperature indicators from 1780 to present rather than 1900 to 2002.

 

EWP

·        Not homogeneous post 1997 as precipitation network is changing.

·        Needs development of new methodology that can work with network changes.

·        Currently have regional, daily time series, back to 1931.  This would allow intensity index to be computed from then on.

·        Could provide data set of changes in seasonal cycle of EWP back to start of record.

·        SRA2002 will deliver regional, daily time series, back to 1890, which will allow computation of various derived indices back to 1980.

 

Ocean temperatures

·        Hadley Centre could deliver homogeneous record for UK waters from 1860 to present (data already exists but would need extraction).  This would be a great improvement on what is planned.

·        Not clear that proposed record meets homogeneity requirement.

·        With more effort could deliver some high resolution data set from 1950’s to present and keep it up-to-date.

 

Westerly weather

·        Have records back to 1950 or so of number of extreme storms.

·        SRA2002 will fund digitisation of records back to 1920/1900 that will extend this record (but not available yet).

·        Wind speed records are very heterogeneous.

·        NAO records been extended back to 1820 or so.

·        Could use reanalysis data from 1948 to present to provide indices of westerly flow.

·        Could use new Hadley data set of monthly-mean pressure to provide a record from mid-19th century to present.

 

Scottish and Irish indices

·        SNIFFER funded production of three temperature data sets to end of 2002.  (UEA carried out the work).

·        No funding to provide these temperature indices in near-real-time.

·        Regional rainfall time series exist for Scotland and NI.