Friday, April 4, 2014

The 2014 Earthtemp network workshop 23rd-25th June, KIT, Germany

Posted on behalf Rosie Graves and Karen Veal

The EarthTemp Network aims to stimulate new international collaboration in measuring and understanding the surface temperatures of Earth. Motivated by the need for better understanding of how different types of measurements relate, including both in situ and satellite observations the network is international but funded by the UK’s Natural Environment Research Council.
The 2014 meeting will bring together about 60 researchers from all over the world who specialise in different types of measurement of surface temperature. The meeting will be specifically designed to review the latest science of surface temperatures for Africa, identify future developments, and, importantly facilitate new connections and collaborations between researchers who may not normally meet. Therefore, the programme emphasizes activities that actively increase networking and interaction between the participants and that enable structured discussions towards the goal of identifying key research opportunities. A preliminary programme can be found at the EarthTemp Network website, follow the links to the ‘Annual themes and workshop’ link on the left hand side.
The meeting will be held on the 23-25th June 2014 at The Karlsruhe Institute of Technology, Karlsruhe, Germany. Registration is free and lunch will be provided each day of the meeting, with a dinner on the Tuesday evening also included. If you are interested in attending this meeting please go to the to the EarthTemp webpage and follow links to the Annual themes and workshop. As places are limited we strongly encourage you to act quickly.
The workshop will be immediately followed by the GlobTemperature 2nd user consultation meeting in the same location, on the 25-26th June. GlobTemperature is a European Space Agency funded project to support the land surface temperature (LST) community to develop products and access mechanisms better suited to users. Participants at the EarthTemp workshop are very welcome to attend this meeting. More details can be found on the GlobTemperature website.

Thursday, February 6, 2014

Workshop on novel approaches to homogenization, Boulder, July 2014

We have long recognized that the enabling framework aspects of the Initiative (databank, benchmarks, data serving) are but one aspect of the problem. What is needed in addition are new approaches to the data homogenization so that we can better understand the data and their uncertainties. This is not something the Initiative can mandate nor something that the 10 cents coin I found following exhaustive searching down the back of my sofa will get us very far in funding. So, we have been and continue to pursue novel means to increase the number of independent groups and individuals undertaking the analysis of the data.

As one such activity, the Initiative put forward a proposal for a SAMSI (Statistical and Applied Mathematical Sciences Institute) summer program activity - which got selected. Over the past few months we have been working with colleagues from SAMSI and NCAR IMAGe (Institute for Mathematics Applied to Geosciences) who joined as substantive co-sponsors to arrange the meeting logistics. We are now in a position to announce the workshop.

So, without further ado ...

Applications are invited for participation in a workshop to be held in Boulder, Colorado July 8th-16th. The aim of the workshop is to develop new and novel techniques for the homogenisation of land surface air temperature data holdings. The workshop participants will have access to the almost 32,000 stations held in the first version databank release (which will be publicly available by then) and also to several of the benchmark datasets. The workshop will mainly be practically based - with few talks and lots of coding and discussions either in plenary or in smaller breakout groups. A final agenda will be forthcoming nearer the time.

Applications are welcome from all. The final meeting is space limited to 44 people. Participants from non-traditional backgrounds, early career scientists and members of under-represented groups are particularly encouraged to apply.

Further meeting details and application form are availble at

Wednesday, January 29, 2014

Initiative progress report published

The overarching initiative progress report has now been published and is available here. This will now be sent to initiative sponsors for their feedback but feedback here is also welcome.

The coming year promises an upward shift in apparent momentum as a result of significant work over the past three years with the release of databank holdings and benchmarks and an exciting workshop to be held in the summer - for more details on the latter watch this space in a few days time.

We will also continue to work with partner activities to further mutual aims.

Thursday, January 16, 2014

All participants meeting Jan 2014

Early in January a meeting of all groups involved in the initiative was held to discuss progress to date and future plans. The minutes from this meeting can be found here. The annual progress reports were discussed (more on this at months end). Also, new terms of reference were adopted for all groups (see the group pages at The coming year promises many new, exciting, developments. Amongst others we expect to see:
  • Release of the version 1 databank which will consist of c.32,000 stations
  • Development and release of benchmarks
  • A workshop held jointly with SAMSI and NCAR on developing novel approaches to dataset homogenization
 We will endeavour to announce major advances through this blog.

Friday, January 10, 2014

The surface temperatures of Earth: steps towards integrated understanding of variability and change

As mentioned back in the summer a paper led by Chris Merchant of Reading University on all aspects of surface temperatures arising from a workshop of the Earthtemp initiative had been submitted to the Open Access EGU journal Geoscientific Instrumentation, Methods and Data Systems. This was accepted and formally published just before Christmas.

The abstract is:
Surface temperature is a key aspect of weather and climate, but the term may refer to different quantities that play interconnected roles and are observed by different means. In a community-based activity in June 2012, the EarthTemp Network brought together 55 researchers from five continents to improve the interaction between scientific communities who focus on surface temperature in particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities. The workshop identified key needs for progress towards meeting scientific and societal requirements for surface temperature understanding and information, which are presented in this community paper. A "whole-Earth" perspective is required with more integrated, collaborative approaches to observing and understanding Earth's various surface temperatures. It is necessary to build understanding of the relationships between different surface temperatures, where presently inadequate, and undertake large-scale systematic intercomparisons. Datasets need to be easier to obtain and exploit for a wide constituency of users, with the differences and complementarities communicated in readily understood terms, and realistic and consistent uncertainty information provided. Steps were also recommended to curate and make available data that are presently inaccessible, develop new observing systems and build capacities to accelerate progress in the accuracy and usability of surface temperature datasets.
If you are interested in broader aspects of the surface temperatures problems and issues than just land surface air temperatures or how ISTI may fit into the whole I would encourage you to read the paper (caveat emptor: I am a co-author). The paper is available at doi:10.5194/gi-2-305-2013. It contains a mix of scientific, practical and development activities which taken as a whole would significantly improve our ability to understand all aspects of global surface temperatures.

Wednesday, December 18, 2013

Surface Temperatures at EGU 2014 - now in PICO format

A guest post by Stephan Matthiesen of the Earthtemp Initiative

Following last year's success, the EarthTemp Network is again organising a session at the EGU 2014 and are looking for abstract submissions. The deadline is 16 Jan., and the EGU Assembly is 27 April - 2 May 2014.

The session "Taking the temperature of the Earth: Temperature Variability and Change across all Domains of Earth's Surface" is motivated by the need for better understanding of in-situ measurements and satellite observations to quantify surface temperatures and invites contributions that emphasize sharing knowledge and make connections across different domains and sub-disciplines. They can include, but are not limited to, topics such as:
  • How to improve remote sensing of ST in different environments
  • Challenges from changes of in-situ observing networks over time
  • Current understanding of how different types of ST inter-­relate
  • Nature of errors and uncertainties in ST observations
  • Mutual/integrated quality control between satellite and in-situ observing systems.
  • What do users of surface temperature data require for practical applications (e.g. in environmental or health sciences)?
We are also excited to try out the new interactive PICO format. PICO (Presenting Interactive COntent) is a new session format developed by EGU designed to be more interactive and specifically to encourage more interaction between presenters and audience.

In practice, this means that there will not be the traditional split between oral presentations and poster session. Each author will get her/his 2 minutes of oral presentation in front of the whole audience. Once this general presentation is over, each author gets their "own" screen and can show the complete presentation, with plenty of time for discussions.

We are thrilled to try out this new format, as it supports the vision of the EarthTemp Network to experiment with new ways of encouraging dialogue and collaborations.

We hope you will help us making this session again a big success with your submissions. The convener is happy to answer all questions about the new PICO format and help with technical issues,
so that your contribution will have an impact.

Abstracts can be submitted (deadline 16 January 2014) through the session website.

Some more information on the EarthTemp Network can be found on the EarthTemp Network Website. We have also just published the final version of the EarthTemp position paper, arising from the first workshop in Edinburgh, in the EGU open access journal Geoscientific Instrumentation, Methods and Data Systems:

Merchant, C. J., Matthiesen, S., Rayner, N. A., Remedios, J. J., Jones, P. D., Olesen, F., Trewin, B., Thorne, P. W., Auchmann, R., Corlett, G. K., Guillevic, P. C., and Hulley, G. C.: The surface temperatures of Earth: steps towards integrated understanding of variability and change, Geosci. Instrum. Method. Data Syst., 2, 305-321, doi:10.5194/gi-2-305-2013, 2013.

Thursday, November 7, 2013

Summary of Regional Inhomogeneities in Surface Temperature

A few months ago the ISTI Benchmarking group made a call to the homogenisation community to submit any times/characters of known inhomogeneities occurring in different regions.

Thanks to the many contributors we now have an overview for a number of countries:
Central Europe

There is always room for more. If you come across any useful information or would just like to see what is there so far please go to:

This is an online editable document so please do add info. A static version will be scraped once a month.


Tuesday, October 29, 2013

Request for support sent from World Meteorological Organization to National Met Services

Earlier this month a letter was circulated from WMO on behalf of the Director General to the Permanent Representatives of its member services (such as NOAA, Met Office, KNMI, Meteo France, BoM, CMA etc.). This letter is a result of discussions at the meeting of the Global Climate Observing System's Atmospheric Observations Panel for Climate in its session earlier this year (report here) and facilitated by GCOS. The letter focusses upon databank aspects of the Initiative. Specifically it asks for help in:
  • Confirming the holdings for stations under the auspices of the national service;
  • Sharing any metadata that is associated with these holdings;
  • Help in sharing any other national data either collected by the national service or not held directly by the national service; and
  • Making available any parallel measurement holdings undertaken by the service as part of their network operations to manage / understand change.
As the letter is an official letter it has been translated into several additional languages. These are currently available online (third party hosted so no guarantee of perpetuity availability clearly). Versions are available in English, French, Russian, Spanish and Arabic.To my knowledge although clearly addressed to the national PRs there is no bona fide restriction on their use in support of appropriate requests through other channels. Clearly any reuse should be appropriate and have a clear cover letter to distinguish that it is supporting material.

While we are discussing the databank ... we are now very much in the final stretch of the development of a stable release. The methods paper has been accepted and as soon as it is available in AOP (probably in the next week or two) we will announce so here. In the meantime i's are being dotted and t's crossed to enable us to go out of beta to a release candidate version concurrent with the paper appearance. Barring discovery of major issues in process forensics the release candidate will become version 1 as soon as due processes have been undertaken.

Tuesday, August 20, 2013

Benchmarking and assessment workshop

Cross-posted from the benchmarking blog.

The workshop agenda and full report can be found here

Below is the executive summary.

1st – 3rd July 2013 Benchmarking Working Group Workshop Report Executive Summary National Climatic Data Center (NCDC) of the National Oceanic and Atmospheric Administration (NOAA), Asheville, NC, USA

Attended in person:
Kate Willett (UK), Matt Menne (USA), Claude Williams (USA), Robert Lund (USA), Enric Aguilar (Spain), Colin Gallagher (USA), Zeke Hausfather (USA), Peter Thorne (USA), Jared Rennie (USA)

Attended by phone:
Ian Jolliffe (UK), Lisa Alexander (Australia), Stefan Brönniman (Switzerland), Lucie A. Vincent (Canada), Victor Venema (Germany), Renate Auchmann (Switzerland), Thordis Thorarinsdottir (Norway), Robert Dunn (UK), David Parker (UK)

A three day workshop was held to bring together some members of the ISTI Benchmarking working group with the aim of making significant progress towards the creation and dissemination of a homogenisation algorithm benchmark system. Specifically, we hoped to have: the method for creating the analog-clean-worlds finalised; the error-model worlds defined and a plan of how to develop these; and the concepts for assessment finalised including a decision on what data/statistics to ask users to return. This was an ambitious plan for three days with numerous issues and big decisions still to be tackled.

The complexity of much of the discussion throughout the three days really highlighted the value of this face-to-face meeting. It was important to take time to ensure that everyone understood and had come to the same conclusion. This was aided by whiteboard illustrations and software exploration, which would not have been possible over a teleconference.

In overview, we made significant progress in terms of developing and converging on concepts and important decisions. We did not complete the work of Team Creation as hoped, but necessary exploration of the existing methods was undertaken revealing significant weaknesses and ideas for new avenues to explore have been found.

The blind and open error-worlds concepts are 95% complete and progress was made on the specifics of the changepoint statistics for each world. Important decisions were also made regarding missing data, length of record and changepoint location frequency. Seasonal cycles were discussed at length and more research has been actioned. A significant first go was made at designing a build methodology for the error-models with some coding examples worked through and different probability distributions explored.

We converged on what we would like to receive from benchmark users for the assessment and worked through some examples of aggregating station results over regions. We will assess both retrieval of trends and climate characteristics in addition to ability to detect changepoints. Contingency tables of some form will also be used. We also hope to have some online or assessment software available so that users can make their own assessment of the open worlds and past versions of benchmarks. We plan to collaborate with the VALUE downscaling validation project where possible.

From an intense three days all participants and teleconference participants gained a better understanding of what we're trying to achieve and how we are going to get there. This was a highly valuable three days, not least through its effect of focussing our attention prior to the meeting and motivating further collaborative work after the meeting. Two new members have agreed to join the effort and their expertise is a fantastic contribution to the project.

Specifically, Kate and Robert are to work on their respective methods for Team Creation, utilising GCM data and the vector autoregressive method. This will result in a publication describing the methodology. We aim to finalise this work in August.

Follow on teleconferences, Team Corruption will focus on completing the distribution specifications and building the probability model to allocate station changepoints. This work is planned for completion by October 2013. Release of the benchmarks is scheduled for November 2013.

Team Validation will continue to develop the specific assessment tests and work these into a software package that can be easily implemented. This work is hoped to be completed by December 2013, but there is more time available as assessment will take place at least 1 year after benchmark release.

Friday, July 19, 2013

New Initiative Implementation Plan published covering 2013-2015

This afternoon we have published a new version of the Initiative over-arching Implementation Plan to cover the period 2013-2015. The document is available from here (pdf, 3.3 Mb).  The plan covers the following major aspects (amongst others):
  • Completion of first version databank release
  • Formulation of databank updates strategy including real-time updates and period of record updates
  • Work on metadata collection
  • Work on construction of a database of parallel (collocated) measurements 
  • Construction of the first set of benchmark analogs and their documentation
  • Development of assessment methods
  • Promotion of benchmarking activities and attempts to ensure multiple groups participate to realize the scientific benefits
  • Communications and outreach
  • Cooperation with other relevant activities
  • Creation of a working group concerned with dataset dissemination and user support
You are, of course, welcome to comment on any aspect of the plan here including things you think we are missing that we should be trying to cover (within the stated remit of the Initiative obviously).

Friday, June 28, 2013

Earthtemp position paper on surface temperatures published - comments are welcome

The EarthTemp community position paper, which reviews the state of art of measuring the surface temperatures of Earth and recommends steps to improve our understanding, has been published as a discussion paper in the open access journal Geoscientific Instrumentation, Methods and Data Systems (Discussions) (GI(D)). As the paper aims to capture a community position and influence future science funding and policy decisions, all interested colleagues are encouraged to submit comments or reviews during the discussion phase (until 6 August) which will then be considered (together with the invited peer-reviews) when preparing the final version of the paper.

The workshop and the paper 
The paper captures the ideas and recommendations developed during the first annual EarthTemp Network meeting in Edinburgh (25-27 June 2012), with invited 55 participants from five continents. The meeting placed particular emphasis on encouraging discussions, networking and collaboration between the participant, featuring networking activities to build relationships across the new community, overviews of the state of the art in the field, and a series of 20 intensive small-group discussions on current gaps in our knowledge and scientific priorities on 5 to 10 year timescales across a number of themes. Chris J. Merchant, the PI of the EarthTemp network, drafted a first version of the paper (available on based on notes and presentations from the chairs of the breakout discussions. The current version for peer-reviewed publication was then developed in several stages, incorporating comments from the Network meeting participants as well as more details, examples and references. The wider community of surface temperature providers and users now has an opportunity to add comments and reviews during the open review phase of the journal Geoscientific Instrumentation, Methods and Data Systems (Discussions) (GI(D)). Like all open access journals published by the European Geoscientific Union (EGU), GI(D) has a two stage publication process: Submitted papers are published very rapidly after an editor's access review as discussion paper. This discussion paper is then sent out for peer-review to reviewers assigned by the handling editor. At the same time, all interested colleagues also have the opportunity to submit comments or reviews through the GI website. Both the official invited peer reviews and the spontaneous comments are public (the official reviewers may chose to remain anonymous, though), and the authors are required to respond (publicly) and address all comments adequately for the final version of the paper. Besides being open access, this open review system adds another aspect of transparency to the work, as readers can monitor the quality of the reviews and the authors' responses. The deadline for comments on the GID journal website is 6 August 2013. We plan to communicate the paper and its recommendations widely to a range of scientific organisations, funding and policy bodies.  

The recommendations 
 The workshop identified the following needs for progress towards meeting societal needs for surface temperature understanding and information, which are summarised in the chart and explained in more detail in the paper: 1 Develop more integrated, collaborative approaches to observing and understanding Earth’s various surface temperatures 2 Build understanding of the relationships between different surface temperatures, where presently inadequate 3 Demonstrate novel underpinning applications of various surface temperature datasets in meteorology and climate 4 Make surface temperature datasets easier to obtain and exploit, for a wider constituency of users 5 Consistently provide realistic uncertainty information with surface temperature datasets 6 Undertake large-scale systematic intercomparisons of surface temperature data and their uncertainties 7 Communicate differences and complementarities of different types of surface temperature datasets in readily understood terms 8 Rescue, curate and make available valuable surface temperature data that are presently inaccessible 9 Maintain and/or develop observing systems for surface temperature data 10 Build capacities to accelerate progress in the accuracy and usability of surface temperature datasets. 
Your views and comments 
We want to encourage all users and providers of surface temperature data, in all domains and for all applications, to contribute your views on the recommendations made in the paper, through the open review on the GID journal website. In view of recommendation 3, we would particularly like to hear from users from outside the climatological and meteorological communities, for example scientists who apply temperature data to questions in ecology, health and epidemiology, society, or public engagement: what kind of data is useful for you and what are barriers to their use in your work?  

Merchant, C. J.; Matthiesen, S.; Rayner, N. A.; Remedios, J. J.; Jones, P. D.; Olesen, F.; Trewin, B.; Thorne, P. W.; Auchmann, R.; Corlett, G. K.; Guillevic, P. C.; Hulley, G. C. (2013): The surface temperatures of the earth: Steps towards integrated understanding of variability and change. Geoscientific Instrumentation, Methods and Data Systems Discussions, 3(1), 305–345. DOI:

You can find out more about Earthtemp at and follow on twitter at

Friday, June 21, 2013

IDL users of the netcdf files databank take note

If using certain versions of IDL (mine for example - 8.0) and sequentially reading, manipulating and then writing out the files there is a pretty spectacular bug in IDL that causes a random crash. It seems that IDL is not dynamically clearing memory between reads for certain unfathomable file combinations. If you are getting issues randomly in such a loop then reset all the read in variables to =0 at the end of the loop each time and these crashes will simply disappear. Ours is clearly not to wonder why, particularly on a Friday ...

Friday, June 14, 2013

Databank beta 4 release

Today we released a fourth beta release of the databank holdings. The associated readme file is available at The fourth beta release involves changes to the metadata format (see the README) and the provision of files in netcdf format. We have made every effort to make these netcdf files compliant with the CF conventions. Put more honestly we have managed to fool the available online python script-based checker into concurring that these are CF compliant. But we would greatly appreciate anyone taing these for a road test and telling us if we are missing things or things break so we can modify the netcdf file formats as necessary.

The formal release is still planned to occur upon acceptance of the methods paper which at this time remains as submitted status at the journal.

The set of stations remains over 30,000, with many longer stations than available in GHCNMv3

Tuesday, June 11, 2013

Notes from meeting open to all initiative participants

Last week we held a call with an open invitation to all those actively participating in the initiative. This call concentrated upon where we stand today and where we want to aim for in the coming two years. It is hoped that we can release a new Implementation Plan to replace the current one by the end of July.

The call notes provide a reasonable snapshot of where we stand today as well as what the open issues are and hence I am publicizing via the blog (there are very many meetings of the steering committee and various groups which it would get more than a tad repetetive (and boring) to highlight each one on this blog but salient / general interest calls we will highlight). Comments on the call notes and constructive suggestions for what we should be aiming to do in the coming two years are most welcome.

The call notes are available from here.

As a heads up we also intend to release a fourth beta of the databank this week. This will include a modicum of further station blacklisting but also a (hopefully) CF-compliant netcdf format version so that people can test this and highlight any issues in our netcdf conversion before formal release of a first version - the timing of which is still dependent upon methods paper acceptance. We'll have a further post when this is up.

Thursday, May 16, 2013

Meeting announcement: Characterising surface temperatures in data-sparse and extreme regions (with a focus on high-latitude domains)

2nd Annual EarthTemp Network Meeting 
12-14 June 2013, Copenhagen 

Data-sparse and extreme regions is the topic of the second year of the network. A focus will be the high-latitude domains, but the network remains inclusive and open to surface temperature researchers of all backgrounds who are interested in sharing knowledge and making connections across sub-discipline boundaries. 

The workshop aims to facilitate collaborations between researchers and will have substantial dialogue and networking activities as well as invited overview presentations, panel discussions and the opportunity to present your work in poster sessions. Sessions planned for the programme are: 

Overview presentations by invited speakers, followed by panel discussions on 
- High-latitude surface temperatures: synthesis of datasets and what they tell us (Kevin Wood) 
- Arctic Land Surface Temperature: Variability and Change (Claude Duguay) 
- Sea Surface Temperature Changes in Polar Regions (Pierre Le Borgne) 
- Sea-Ice Surface Temperature Measurements: Status and Utility (Jacob Hoyer) 
Plenary discussion: Combined interpretation of Arctic temperatures Networking activities 

Breakout discussion groups on 
- Techniques for matching measurements and retrievals across different platforms 
- Measurement of high-latitude Surface Temperature (SST): Why is it difficult, and how can we do it better? 
- Satellite Land Surface Temperatures (LST) in high latitudes and high altitudes: How can we exploit them better? 
- The EarthTemp White Paper: Turning recommendations into actions 

Poster sessions & Poster discussions 

There is no attendance fee. 

The workshop is limited to 50 participants. 

Monday, May 13, 2013

Call for regional inhomogeneity info

To create realistic benchmarks we would like to reproduce times and locations of known sources of inhomogeneity as best we can. Please can you help us. If you know of any regional/countrywide changes to the observing system over time please can you list them here or point us to some documentation/reference. Any information is valuable - even if its quite vague.

Ideally we'd like to know:

WHEN - specific date or month or year or even decade etc.
WHERE - a region, a country, an international GTS/WMO change etc.
WHAT - a change in shelter, thermometer type, automation, observing time/practice etc.
HOW - are there any estimates of the size/direction/nature of the effect of this change?

Please post here and encourage others to do so. We then hope to reward you with some realistic error-worlds to play with.

Kate (and the Benchmarking working group)

Thursday, April 18, 2013

Initiative posters at 2013 EGU

There were two posters presented at EGU this year outlining Initiative progress and promoting the use of the databank by groups interested in the challenge of surface temperature data homogenization. I didn't attend myself, but the second hand feedback I have received off the named presenters is that they were generally well received.

One thing that was requested by some was help in getting funding. Sadly, we don't have funding for anything directly, but we are more than happy to write letters of support for any work that furthers the aims of the initiative to funding bodies.

Friday, March 22, 2013

Initiative progress report published

The initiative progress report has been published and shared with our 'sponsors'. This provides a useful overview of what has been acheived and what is intended to occur in the next year. Its been delayed due to demands on folks time. But still, better late than never. Comments and feedback are welcome. All progress reports are archived at

Monday, March 18, 2013

Databank Release: Beta #3

We are nearing an official version 1 release of the global land surface databank. However, because there have been major changes since the last beta release in December, it seemed adequate to push out one more beta for the public to provide any comments.

The beta3 release can be found here: Within that directory one can find all the data and code used, along with some graphics depicting the results of all the merge variants.

In addition, the previous betas are still available to look at, if anyone wishes to run comparisons
The next couple of posts will highlight changes and additions to this beta release, however here are the highlights:
  • A blacklist of candidate stations was generated to either fix known errors with its metadata/data, or withhold the station completely. This is a required input file for the code to run and is provided with this beta release
  • Some minor code changes were applied, including withholding stations when the metadata probability was near perfect, but the data comparisons were so poor the station became unique (when it should have merged). In addition, odd characters were removed from the station name before the Jaccard Index was run.
  • The format of stage 3 data was changed so that it was consistent with all stage 2 data. In addition, all data provenance flags have been ported over in order to be open and transparent
  • Algorithm output is included with each variant result, in order to provide information about each candidate station and how it made it's decision to merge / unique / withhold. A future post will go into great detail about each output file.
As usual these are not considered the final revisions prior to an official Version 1 release. In addition all documentation provided on the FTP site will be superseded with a published version of the databank merge methodology paper, which we are working hard to submit to a peer-reviewed journal soon.

If you wish to provide comments, please feel free to send an e-mail to

Thursday, February 7, 2013

A database with daily climate data for more reliable studies of changes in extreme weather

Repost from the blog Variable Variability.

In summary:
  • We want to build a global database of parallel measurements: observations of the same climatic parameter made independently at the same site
  • This will help research in many fields
    • Studies of how inhomogeneities affect the behaviour of daily data (variability and extreme weather)
    • Improvement of daily homogenisation algorithms
    • Improvement of robust daily climate data for analysis
  • Please help us to develop such a dataset


One way to study the influence of changes in measurement techniques is by making simultaneous measurements with historical and current instruments, procedures or screens. This picture shows three meteorological shelters next to each other in Murcia (Spain). The rightmost shelter is a replica of the Montsouri screen, in use in Spain and many European countries in the late 19th century and early 20th century. In the middle, Stevenson screen equipped with automatic sensors. Leftmost, Stevenson screen equipped with conventional meteorological instruments.
Picture: Project SCREEN, Center for Climate Change, Universitat Rovira i Virgili, Spain.

We intend to build a database with parallel measurements to study non-climatic changes in the climate record. This is especially important for studies on weather extremes where the distribution of the daily data employed must not be affected by non-climatic changes.

There are many parallel measurements from numerous previous studies analysing the influence of different measurement set-ups on average quantities, especially average annual and monthly temperature. Increasingly, changes in the distribution of daily and sub-daily values are also being investigated (Auchmann and Bönnimann, 2012; Brandsma and Van der Meulen, 2008; Böhm et al., 2010; Brunet et al., 2010; Perry et al., 2006; Trewin, 2012; Van der Meulen and Brandsma, 2008). However, the number of such studies is still limited, while the number of questions that can and need to be answered are much larger for daily data.

Unfortunately, the current common practice is not to share parallel measurements and the analyses have thus been limited to smaller national or regional datasets, in most cases simply to a single station with multiple measurement set-ups. Consequently there is a pressing need for a large global database of parallel measurements on a daily or sub-daily scale.

Also datasets from pairs of nearby stations, while officially not parallel measurements, are interesting to study the influence of relocations. Especially, typical types of relocations, such as the relocation of weather stations from urban areas to airports, could be studied this way. In addition, the influence of urbanization can be studied on pairs of nearby stations.

Daily data

Daily datasets are essential for studying the variability of and extremes in weather and climate. Looking at the physical causes of inhomogeneities, one would expect that many of the effects are amplified on days with special weather conditions and thus especially affect the tails of the distribution of the daily data. Now that the interest in extreme weather and thus in daily data has increased, more and more people are also working on the homogenization of daily data. Increasingly, developers of national and regional temperature datasets have homogenised the temperature distribution (see e.g., Nemec et al., 2012; Auer et al., 2010; Brown et al., 2010; Kuglitsch et al., 2009, 2010). Further improvements in the quantity and quality of such datasets, and a deeper understanding of remaining deficiencies, are important for climatology.

Application possibilities of parallel measurements

The most straightforward application of such a dataset would be a comparison of the magnitude of the non-climatic changes to the magnitude of the changes found in the climate record. We need to know whether the non-climatic changes are large enough to artificially hide or strengthen any trends or perturb decadal variability. In addition, such a dataset would help us to better understand the physical causes of inhomogeneities. A large and quasi-global dataset would enable to analyse how the magnitude and nature of inhomogeneities differ depending on the geographical region and the microclimate.

The dataset would also benefit homogenisation science in multiple ways. It may reveal typical statistical characteristics of inhomogeneities that would allow for a more accurate detection and correction of breaks. The dataset would facilitate the development of physical homogenisation methods for specific types of breaks that are able to take the weather conditions into account; similar to the method developed for the transition of Wild screens to Stevenson screens for Switzerland by Auchmann and Brönnimann (2012). It would also allow for the development of generalised physical correction methods suitable for multiple climatic regions. Finally, the dataset would improve the ability to create realistic validation datasets, thus improving our estimates of the remaining uncertainties. This in turn again benefits the development of better homogenisation methods.

Organisational matters

As an incentive to contribute to the dataset, initially only contributors will be able to access the data. After joint publications, the dataset will be opened for academic research as a common resource for the climate sciences. These two stages will also enable us to find errors in the dataset before the dataset is published.

The International Surface Temperature Initiative (ISTI) and the European Climate Assessment & Dataset (ECA&D) are willing to host the dataset. This is great, because it makes the dataset more visible for contributors and users alike. We are still looking for an organisational platform that could facilitate the building of such a dataset. Any ideas for this are appreciated.

A preliminary list with parallel measurements can be found in our Wiki.

If you have any ideas or suggestions for such an initiative, if you know of further parallel datasets, or if you just want to be kept informed, please update our Wiki, comment at Variable Variability or send an email to Furthermore, if you know someone who might be interested, please inform him or her about this initiative. Thank you.

Scientists involved in this initiative are:

  • Enric Aguilar (University of Tarragona, Spain)
  • Renate Auchmann (University of Bern, Switzerland)
  • Ingeborg Auer (Zentralanstalt für Meteorologie und Geodynamik, Austria)
  • Andreas Becker (Global Precipitation Climatology Centre, Deutscher Wetterdienst, Germany)
  • Stefan Brönnimann (Institute of Geography, University of Bern, Switzerland)
  • Michele Brunetti (Institute of Atmospheric Sciences and Climate of the National Research Council, Italy)
  • Sorin Cheval (National Meteorological Administration, Romania)
  • Peter Domonkos (University of Tarragona, Spain)
  • Aryan van Engelen (Royal Netherlands Weather Service, The Netherlands)
  • José Guijarro (Agencia Estatal de Meteorología, Spain)
  • Franz Gunther Kuglitsch (GFZ German Research Centre for Geosciences, Germany)
  • Monika Lakatos (Hungarian Meteorological Service, Hungary)
  • Øyvind Nordli (Meteorologisk institutt, Norway)
  • David Parker (UK MetOffice, United Kingdom)
  • Mário Gonzalez Pereira (Universidade de Trás-os-Montes e Alto Douro, Portugal)
  • Tamas Szentimrey (Hungarian Meteorological Service, Hungary)
  • Peter Thorne (National Climatic Data Center, USA; International Surface Temperature Initiative)
  • Victor Venema (University of Bonn, Germany)
  • Kate Willett (UK MetOffice, United Kingdom)

Related posts

Future research in homogenisation of climate data – EMS 2012 in Poland
A discussion on homogenisation at a Side Meeting at EMS2012
What is a change in extreme weather?
Two possible definitions, one for impact studies, one for understanding.
HUME: Homogenisation, Uncertainty Measures and Extreme weather
Proposal for future research in homogenisation of climate network data.
Homogenization of monthly and annual data from surface stations
A short description of the causes of inhomogeneities in climate data (non-climatic variability) and how to remove it using the relative homogenization approach.
New article: Benchmarking homogenization algorithms for monthly data
Raw climate records contain changes due to non-climatic factors, such as relocations of stations or changes in instrumentation. This post introduces an article that tested how well such non-climatic factors can be removed.


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Auer I., Nemec J., Gruber C., Chimani B., Türk K. HOM-START. Homogenisation of climate series on a daily basis, an application to the StartClim dataset. Wien: Klima- und Energiefonds, Projektbericht, 34 p., 2010.

Brandsma, T. and J.P. van der Meulen, Thermometer Screen Intercomparison in De Bilt (the Nether-lands), Part II: Description and modeling of mean temperature differences and extremes. Int. J. Climatology, 28, pp. 389-400, 2008.

Brown, P. J., R. S. Bradley, and F. T. Keimig. Changes in extreme climate indices for the northeastern United states, 1870–2005, J. Clim., 23, 6555–6572, doi: 10.1175/2010JCLI3363.1, 2010.

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Brunet, M., J. Asin, J. Sigró, M. Banón, F. García, E. Aguilar, J. Esteban Palenzuela, T.C. Peterson and P. Jones. The minimization of the screen bias from ancient Western Mediterranean air temperature records: an exploratory statistical analysis. Int. J. Climatol., doi: 10.1002/joc.2192, 2010.

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Kuglitsch F.G., Toreti A., Xoplaki E., Della-Marta P.M., Luterbacher J., Wanner H. Homogenisation of daily maximum temperature series in the Mediterranean. Journal of Geophysical Research, 114, art. no. D15108, doi: 10.1029/2008JD011606, 2009.

Kuglitsch F.G., Toreti A., Xoplaki E., Della-Marta P.M., Zerefos C.S., Türkes M., Luterbacher J. Heat wave changes in the eastern Mediterranean since 1960. Geophysical Research Letters, 37, L04802, doi: 10.1029/2009GL041841, 2010.

Meulen, van der, JP, T Brandsma. Thermometer screen intercomparison in De Bilt (The Netherlands), part I: Understanding the weather-dependent temperature differences. Int. J. Climatol., 28, 371-387, 2008.

Nemec, J., Ch. Gruber, B. Chimani, I. Auer. Trends in extreme temperature indices in Austria based on a new homogenised dataset. Int. J. Climatol., doi: 10.1002/joc.3532, 2012.

Perry, M., Prior, J. and Parker, D.E., 2006: An assessment of the suitability of a plastic thermometer screen for climatic data collection. Int. J. Climatol., 27, 267-276.

Trewin, B. A daily homogenized temperature data set for Australia. Int. J. Climatol., doi: 10.1002/joc.3530, 2012.

Thorne, Peter W., Kate M. Willett, Rob J. Allan, Stephan Bojinskski, John R. Christy, Nigel Fox, Simon Gilbert, Ian Jolliffffe, John J. Kennedy, Elizabeth Kent, Albert Klein Tank, Jay Lawrimore, David E. Parker, Nick Rayner, Adrian Simmons, Lianchun Song, Peter A. Stott, and Blair Trewin 2011: Guiding the Creation of A Comprehensive Surface Temperature Resource for Twenty-First-Century Climate Science. Bull. Amer. Meteor. Soc., 92, ES40–ES47. doi: 10.1175/2011BAMS3124.1. More information at: