UK Climate Projections News

13 October 2021: Update and Improvements to the UKCP Probabilistic Projections

We previously announced that we found some inconsistencies between the maximum, minimum and mean daily temperature data in the Probabilistic Projections. As part of the continual review and improvement of UKCP data products and services, we are currently updating the UKCP Probabilistic Projections to correct this issue. This update will also include improvements to the statistical treatment of precipitation and decadal variability. For precipitation, the update will lead to improved dry-end extremes.

We plan to release the updated data this winter alongside a technical note and guidance. As in our previous announcement, we remind you that you should not use maximum and minimum surface air temperatures from the UKCP Probabilistic Projections that were released in November 2018. Many other UKCP Products include maximum and minimum daily temperatures. For instance, in the interim you could use the Probabilistic Projections of Climate Extremes that provide future projections of maximum daily temperatures or data from UKCP Regional (12km) or UKCP Local (2.2km). Should you have further queries please contact the UKCP team for further advice.

The inconsistencies mentioned above were found in response to user feedback. Following an extensive investigation, we found a software indexing error in one of our climate model datasets that offsets the seasonal cycle of maximum and minimum temperature data by one month. This problem does not affect daily-average temperature, or other variables in the UKCP Probabilistic Projections. It also does not affect any other UKCP product.

 

22 July 2021: UKCP Local (2.2km) Update 

The UKCP Local (2.2km) data have been updated, following a correction to the computer code identified in September 2020 and some additional science improvements. Top-level climate change messages from UKCP are unchanged because no other UKCP product is affected. For any application, we still recommend considering the full suite of UKCP products. The new Local (2.2km) data generally shows improved consistency with the Regional (12km) data.  

The code error related to how much solid precipitation falls as snow and how much as graupel (small, soft ice pellets that typically form in convective clouds). The science improvements mainly relate to the representation of the snowpack. Full details can be found in the UKCP Local Update Report and FAQ, both available from the Guidance and Science Reports page.  

For this reason, snow is primarily affected, and in turn winter temperature and hourly precipitation extremes. Where these variables have been studied using the Local (2.2km) data, the analysis should be repeated using this new data. Winter mean precipitation and heavy daily precipitation events are affected in present-day climate, but the future changes are not significantly different in the new Local (2.2km) data. There should be little effect on summer temperature, summer mean precipitation and cloud cover.  

To reflect the changes, we have updated the following documentation: 

  • UKCP Headline Findings contains updated statements that are not qualitatively different but the UKCP Local-based numbers have been updated.  

  • UKCP Local (2.2km) Update Report describes the full details of the change and its effects on the data, including figures that update those in the UKCP Local (Convection-Permitting Model) Science Report.  Both are available from the Science Reports and Guidance page

  • UKCP Factsheet on Snow has updated plots and analysis, available from the Factsheet page.  

On fixing the graupel error, the simulation of lightning is considerably improved. Therefore, we are releasing a lightning metric: the number of lightning flashes per day (‘flashrate’). For details, see the updated data availability document (also available from the Science Report and Guidance page).  

 

22 July 2021: FUTURE-DRAINAGE - The first user application of the new UKCP Local (2.2km) projections

Uplifts from the UKRI project FUTURE-DRAINAGE (led by Newcastle University) have been released to coincide with the UKCP Local (2.2km) update. This is the first user application of the new UKCP Local (2.2km) projections, providing new estimates of short-duration precipitation extremes. Results have been tailored to stakeholder needs, to help inform flood management and urban drainage design in a changing climate.

 

October 2020: UKCP Enhancements

A set of enhancements to the available UKCP products are now available; these include an assessment of extremes within the Probabilistic Projections, a low emissions scenario update for UKCP Global (60 km), an assessment of the internal variability within the UKCP Projections, three European circulation indices and data on soil moisture and water balance.   

Increasingly extreme weather is one of the greatest impacts from climate change, the UKCP Probabilistic Projections of Climate Extremes provide information on 21st Century temperature and precipitation extremes across the UK.  They use a similar methodology to the UKCP Probabilistic Projections published in 2018 augmented by the use of extreme value theory to support projections of long return-period events.  The data is available from the UKCP User Interface and the CEDA Archive and described in the following documents: 

UKCP Global (60 km) was one of the products released as part of the UK Climate Projections in 2018, comprising climate model simulations using a high emissions scenario (RCP 8.5). To ensure users can investigate a wider range of scenario uncertainty, the UKCP Global product has been updated to include a low emissions scenario (RCP 2.6). The data is available from the UKCP User Interface and the CEDA Archive and is described in:

An additional set of information is available for those user who wish to explore in more detail the behaviour of the UKCP suite of climate models. This includes three European climate indices, representing the large scale drivers of UK weather and climate within UKCP Global. The data is available from the CEDA Archive and described in the following factsheets:

Soil moisture and water balance metrics are also now available for UKCP Global (60 km) and UKCP Regional (12 km) products on the CEDA Archive. The data is summarised in:

A report that details the role that internal variability of UKCP global climate models:

You can find out more in the press release.

 

24 September 2020: UKCP Updates

Some elements of UKCP will be receiving updates, including a scheduled release of increased functionality, and two amendments fixing errors with the computer code. 

UKCP Local 2.2km correction 

Users of the UKCP Local 2.2km climate model should be aware of an error within the computer code, affecting how much solid precipitation falls as snow and how much falls as small ice pellets. No other UKCP product is affected by the error and top-level UK climate change messages from UKCP are unchanged.  Much of the existing 2.2km data can still be used for many applications, but users are urged not to use data containing projections of snow and winter temperatures over Scotland. 

The following variables are also affected, but to a lesser extent, and for these caution is needed in the use of the existing data: winter precipitation; UK hourly precipitation extremes; and wind extremes over the ocean and north-west coastal regions.  Summer temperature, including extremes and summer mean precipitation remain unaffected. 

The UKCP team are planning to issue revised data in Spring 2021.  A report for technical users providing more detail on this issue and guidance to help users understand how to best continue in their use of the model results is available, along with an FAQ document

Probabilistic Projections investigation 

In response to feedback from a user, the UKCP team have checked projections of daily minimum and maximum surface air temperature (Tmin and Tmax) from the probabilistic projections’ component of the land scenarios (UKCP_Probabilistic). In climate model output, changes in daily mean temperature (Tmean) are usually within 0.5 degrees of the average of changes in Tmax and Tmin. However, in the UKCP_Probabilistic data larger differences were found in some of the 3000 realisations, leading to inconsistencies between the Tmax, Tmin and Tmean results. We will report back on a time-scale of approximately one month, with updated data and guidance.  

Any users of the current Tmax and Tmin results from UKCP Probabilistic who need a faster response are advised to contact the UKCP team for further advice. Other variables in UKCP Probabilistic, including daily-average temperature, are not affected by this issue. 

UKCP enhanced capability 

During October 2020, a suite of new tools delivering advanced functionality will become available. The new features include: 

  • Probabilistic estimates for a range of extreme metrics at return periods of 20, 50 and 100 years for quantities such as daily maximum temperature, and daily precipitation.  
  • Storm and weather-related metrics – including NAO indices, storm track position and intensity, and weather types.  
  • Guidance on water budgets and guidance on global model drifts.   


16 September 2019: UKCP Local (2.2km) climate projections now available 

Today, Defra, BEIS, Met Office and the Environment Agency mark the release of the UKCP Local (2.2km) climate projections with an event taking place in London and hosted by Professor Sir Ian Boyd, with a keynote presentation from Professor Christoph Schär.

The new climate projections complement the UKCP suite of products launched last year. They are the highest ever resolution of climate projections produced for the UK, for the first time on a par with the resolution used for weather forecasting. They provide information to help society to understand how much the climate might change in future, enabling comprehensive adaptation planning to inform how to protect people and infrastructure. Read the press release.

The science team behind the projections are confident that the enhanced detail of these cutting-edge projections – when viewed alongside other UKCP products – provides further comprehensive information on future climate change of key importance for local decision-making and planning.


8 April 2019: Probabilistic projections for aggregated regions now available

We’ve added a new dataset to the UK Climate Projections User Interface: the probabilistic projections for aggregated regions. This provides projected changes for not only river basin regions and administrative regions (similar to that available in UKCP09) but also the UK and its devolved administrations.

In producing this new dataset, we made some improvements to the method (see footnote on page 24 of the land projections report). We’ve also made minor changes to the science overview, land projections report and text and figures in the headline findings  to reflect these improvements.

In response to some user queries, we’ve also published a new technical note clarifying characteristics of the probabilistic projections data such as the clipping at the extremes ends of the distributions and non-zero sum of anomalies during the baseline period.

 

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