Monday, October 6, 2014

A framework for benchmarking of homogenisation algorithm performance on the global scale - Paper now published

The ISTI benchmarking working group have just had their first benchmarking paper accepted at Geoscientific Instrumentation, Methods and Data Systems:

Willett, K., Williams, C., Jolliffe, I. T., Lund, R., Alexander, L. V., Brönnimann, S., Vincent, L. A., Easterbrook, S., Venema, V. K. C., Berry, D., Warren, R. E., Lopardo, G., Auchmann, R., Aguilar, E., Menne, M. J., Gallagher, C., Hausfather, Z., Thorarinsdottir, T., and Thorne, P. W.: A framework for benchmarking of homogenisation algorithm performance on the global scale, Geosci. Instrum. Method. Data Syst., 3, 187-200, doi:10.5194/gi-3-187-2014, 2014.

Benchmarking, in this context, is the assessment of homogenisation algorithm performance against a set of realistic synthetic worlds of station data where the locations and size/shape of inhomogeneities are known a priori. Crucially, these inhomogeneities are not known to those performing the homogenisation, only those performing the assessment. Assessment of both the ability of algorithms to find changepoints and accurately return the synthetic data to its clean form (prior to addition of inhomogeneity) has three main purposes:

      1) quantification of uncertainty remaining in the data due to inhomogeneity
      2) inter-comparison of climate data products in terms of fitness for a specified purpose
      3) providing a tool for further improvement in homogenisation algorithms

Here we describe what we believe would be a good approach to a comprehensive homogenisation algorithm benchmarking system. Thfis includes an overarching cycle of: benchmark development; release of formal benchmarks; assessment of homogenised benchmarks and an overview of where we can improve for next time around (Figure 1).

Figure 1 Overview the ISTI comprehensive benchmarking system for assessing performance of homogenisation algorithms. (Fig. 3 of Willett et al., 2014)

There are four components to creating this benchmarking system. 

Creation of realistic clean synthetic station data

Firstly, we must be able to synthetically recreate the 30000+ ISTI stations such that they have the correct variability, auto-correlation and interstation cross-correlations as the real data but are free from systematic error. In other words, they must contain a realistic seasonal cycle and features of natural variability (e.g., ENSO, volcanic eruptions etc.). There must be a realistic persistence month-to-month in each station and geographically across nearby stations. 

Creation of realistic error models to add to the clean station data

The added inhomogeneities should cover all known types of inhomogeneity in terms of their frequency, magnitude and seasonal behaviour. For example, inhomogeneities could be any or a combination of the following:

     -  geographically or temporally clustered due to events which affect entire networks or regions (e.g. change in observation time);
     -  close to end points of time series;
     -  gradual or sudden;
     -  variance-altering;
     -  combined with the presence of a long-term background trend;
     - small or large;

     - frequent;
     - seasonally or diurnally varying.

Design of an assessment system

Assessment of the homogenised benchmarks should be designed with the three purposes of benchmarking in mind. Both the ability to correctly locate changepoints and to adjust the data back to its homogeneous state are important. It can be split into four different levels:

     - Level 1: The ability of the algorithm to restore an inhomogeneous world to its clean world state in terms of climatology, variance and trends.

     - Level 2: The ability of the algorithm to accurately locate changepoints and detect their size/shape.

     - Level 3: The strengths and weaknesses of an algorithm against specific types of inhomogeneity and observing system issues.

     - Level 4: A comparison of the benchmarks with the real world in terms of detected inhomogeneity both to measure algorithm performance in the real world and to enable future improvement to the benchmarks.

The benchmark cycle

This should all take place within a well laid out framework to encourage people to take part and make the results as useful as possible. Timing is important. Too long a cycle will mean that the benchmarks become outdated. Too short a cycle will reduce the number of groups able to participate.

Producing the clean synthetic station data on the global scale is a complicated task that has now taken several years but we are close to completion of a version 1. We have collected together a list of known regionwide inhomogeneities and a comprehensive understanding of the many many different types of inhomogeneities that can affect station data. We have also considered a number of assessment options and decided to focus on levels 1 and 2 for assessment within the benchmark cycle. Our benchmarking working group is aiming for release of the first benchmarks by January 2015.

Friday, September 12, 2014

The Databank Near Real Time Update System

Since the official release back in June, we have worked to keep the databank updated with the most recent data. Each month we will post new data from sources that update in near-real-time (NRT), along with an updated version of the recommended merge with the latest data appended. Stage 1 data (digitized in its original form) will be updated no later than the 5th of each month, and then Stage 2 (common formatted data) and Stage 3 (merged record) data will be updated no later than the 11th of the month.

So what data gets updated in our NRT system? We have determined four sources that have updated data within the first few days of the month. They are the CLIMAT streams from NCDC as well as the UK, the unpublished form of the monthly climatic data for the world (MCDW) and finally GHCN-D. Similar to the merge program, a hierarchy is placed determining which source its data appends to if there are conflicts. The hierarchy is here:

1) GHCN-D
2) CLIMAT-UK
3) CLIMAT-NCDC
4) MCDW-Unpublished

An overview of the system is shown here in this flow diagram (Click on image to enlarge):

The algorithm to append data looks for station matches through the same metadata tests as described in the merge program. These include geographic distance, height distance, and station name similarity using the Jaccard Index. If the metadata metric is good, then an ID test is used to determine station match. Because the four input sources have either a GHCN-D or WMO ID, the matching is much easier here than in the merge program. Once a station match is found, new data from the past few months are appended. Throughout this process, no new stations are added.

We have had two monthly updates so far. As always the latest recommended merge data can be found on our ftp page here, along with older data placed in the archive here. Note that we are only updating the recommended merge, and not the variants. In addition, the merge metadata is not updated, because no new merge has been applied yet. We plan to have another merge out sometime in early 2015.

Friday, August 29, 2014

ccc-gistemp and ISTI

This is a guest post by David Jones of the Climate Code Foundation. It is a mirror of their post at http://climatecode.org/blog/2014/08/ccc-gistemp-and-isti/

ccc-gistemp is Climate Code Foundation‘s rewrite of the NASA GISS Surface Temperature Analysis GISTEMP. It produces exactly the same result, but is written in clear Python.

I’ve recently modified ccc-gistemp so that it can use the dataset recently released by the International Surface Temperature Initiative. Normally ccc-gistemp uses GHCN-M, but the ISTI dataset is much larger. Since ISTI publish the Stage 3 dataset in the same format as GHCN-M v3 the required changes were relatively minor, and Climate Code Foundation appreciates the fact that ISTI is published in several formats, including GHCN-M v3.

The ISTI dataset is not quality controlled, so, after re-reading section 3.3 of Lawrimore et al 2011, I implemented an extremely simple quality control scheme, MADQC. In MADQC a data value is rejected if its distance from the median (for its station’s named month) exceeds 5 times the median absolute deviation (MAD, hence MADQC); any series with fewer than 20 values (for each named month) is rejected.

So far I’ve found MADQC to be reasonable at rejecting the grossest non climatic errors.

Let’s compare the ccc-gistemp analysis using the ISTI Stage 3 dataset versus using the GHCN-M QCU dataset. The analysis for each hemisphere:

For both hemispheres the agreement is generally good and certainly within the published error bounds.

Zooming in on the recent period:

Now we can see the agreement in the northern hemisphere is excellent. In the southern hemisphere agreement is very good. The trend is slightly higher for the ISTI dataset.

The additional data that ISTI has gathered is most welcome, and this analysis shows that the warming trend in both hemispheres was not due to choosing a particular set of stations for GHCN-M. The much more comprehensive station network of ISTI shows the same trends.

Thursday, July 24, 2014

The WMO Commission for Climatology meeting and developments on the WMO front



The World Meteorological Organization’s Commission for Climatology had its four-yearly meeting in Heidelberg, Germany, from 3-8 July, preceded by a Technical Conference from 30 June – 2 July. The Commission is the central body for climate-related activities in WMO, and has a major role in establishing international standards and setting international work programs in the climate field, particularly through setting up networks of Expert Teams and Task Teams to work on particular issues. Its  President (re-elected at the meeting) is Tom Peterson of NCDC, who will be well-known to many of you. The International Surface Temperature Initiative was set up as the result of a resolution of the last Commission for Climatology meeting, in 2010.

I made a presentation to the Technical Conference on the current status of ISTI. By happy coincidence, this presentation was scheduled for the morning on 1 July, a few hours after the release of the first version of the ISTI databank. The presentation appeared to be well-received; there were few direct questions or follow-ups, but the pile of leaflets we brought describing ISTI (once they got there, after a couple of bonus days enjoying Berlin with the rest of my luggage) was a lot smaller at the end of the week than it was at the start. One particular reason for targeting the Commission audience is that many of the attendees at Commission meetings are senior managers in their national meteorological services (often the head of the climate division, or equivalent), and so potentially have more influence over decisions to make data available to projects such as ISTI than individual scientists would.

Slow progress is also being made in two other areas of WMO of interest to ISTI. The inclusion of at least some historic climate data amongst the set of products which countries agree to freely exchange has been a long-standing goal of ours. The key decisions on this will be made at the full WMO Congress, which will be held next year, but progress to date (including through the recent WMO Executive Council meeting) is encouraging. There are also moves to include the month’s daily data in monthly CLIMAT messages, which are the principal means of exchanging current climate data through the WMO system but currently only contain monthly data. This will be very useful for the ongoing updating of data sets, as it will make daily data available which can be assumed to be for a full 24-hour day and is likely to have received at least some quality control (neither of which is necessarily true for the real-time synoptic reports which are the primary current source of recent daily and sub-daily data). Considerable technical work remains to be done, though, to implement this, even once it is formally endorsed.

Data rescue and climate database systems continue to be a high priority of the Commission, with several initiatives outlined at the meeting. Among them are proposals for an international data rescue portal, which (among other things) would potentially facilitate crowd-sourced digitisation. It is, however, an indication of how much work still remains to be done in many parts of the world that, according to results of a survey reported at the meeting, 25% of responding countries still stored their country’s climate data in spreadsheets or flat files, and 40% had a climate database system which was not fully functioning or not functioning at all.

The Commission also agreed to establish a new Task Team on Homogenisation. The full membership (and chairing) of this group are not yet clear but I will almost certainly be part of it. This team will be working closely with ISTI, but will also have a major focus on supporting the implementation of homogenised data sets which contribute to operational data products nationally and internationally.

Also of interest to ISTI is a new WMO initiative to formally recognise “centennial stations”, which, as the name implies, are stations which have existed with few or no changes for 100 years or more. Countries are to be asked to identify such stations, whose data will clearly be of considerable value to ISTI, if not already part of our databank. Free access to data and relevant metadata are among the recommendations for centennial stations.

And one advantage of holding an international meeting during the World Cup: it provides an instant conversation-starter with delegates of almost any country. (Perhaps fortunately for the Brazilian delegation, the meeting finished just before the semi-finals).

(Update 5 August: the resolution which came out of the WMO Executive Council meeting is available at


Monday, July 21, 2014

Later talks from SAMSI / IMAGe workshop

Following up to the previous post there were two further recorded talks at the event.

http://video.ucar.edu/mms/image/samsi2014_jonathan_woody.mp4 - Jonathan Woody gave a talk on analyses of snow depth.

http://video.ucar.edu/mms/image/samsi2014_bo_li.mp4 - Bo Li provided a talk on model selection in the use of palaeodata analyses.

We hope to have a meeting report out within a matter of days to weeks. We will post this here.

Overall there was a lot of active participation and many new directions to be taken in the analysis of surface temperatures. Our thanks go out to both SAMSI and IMAGe for facilitating this meeting and to all the participants for being active. More details to appear soon ...

Friday, July 11, 2014

Talks from SAMSI / IMAGe workshop on International Surface Temperature Intiative

We are currently in-situ in Boulder at a workshop organized with SAMSI and IMAGe. Work is ongoing and a formal write up will follow after completion. Most, but not all, of the talks have been streamed and are available for viewing.

http://video.ucar.edu/mms/image/samsi2014_richard_smith.mp4 - Richard Smith provided an overview of the SAMSI program and their expectations for the workshop.

http://video.ucar.edu/mms/image/samsi2014_peter_thorne.mp4 - I provided an overview of the ISTI program and progress to date

http://video.ucar.edu/mms/image/samsi2014_peter_thorne_jared.mp4 - I deputized for Jared to provide an overview of the databank process

http://video.ucar.edu/mms/image/samsi2014_kate_willet.mp4 - Kate Willett provided an overview of progress with creation of benchmarks and remaining challenges.

http://video.ucar.edu/mms/image/samsi2014_lucie_vincent.mp4 - Lucie Vincent provided an overview of typical inhomogeneities found in station timeseries and some of their likely causes.

http://video.ucar.edu/mms/image/samsi2014_jaxk_reeves.mp4 - Jaxk Reeves provided an overview of at most one changepoint techniques.

http://video.ucar.edu/mms/image/samsi2014_colon_gallagher.mp4 - Colin Gallagher provided an overview of fitting regression models.

http://video.ucar.edu/mms/image/samsi2014_robert_lund.mp4 - Robert Lund provided an overview of multiple changepoint techniques.

http://video.ucar.edu/mms/image/samsi2014_enric_aguilar.mp4 - Enric Aguilar and http://video.ucar.edu/mms/image/samsi2014_victor_venema.mp4 Victor Venema provided an overview of several state of the art climate homogenization techniques.

http://video.ucar.edu/mms/image/samsi2014_matt_menne.mp4 - Matt Menne provided and overview of the Pairwise Homogenization Algorithm and Bayes Factor Analyses by NCDC and their benchmarking.

http://video.ucar.edu/mms/image/samsi2014_peter_thorne2.mp4 - I provided an overview of uncertainty quantification in climate datasets.

http://video.ucar.edu/mms/image/samsi2014_colin_morice.mp4 - Colin Morice provided an overview of the HadCRUT4 uncertainty estimation techniques.

http://video.ucar.edu/mms/image/samsi2014_doug_nychka.mp4 - Doug Nychka provided an overview of spatial statistical aspects.

http://video.ucar.edu/mms/image/samsi2014_jeff_whitaker.mp4 - Jeff Whitaker provided an overview of comparisons between surface temperature products and dynamical reanalyses driven solely by observed SSTs and surface pressure measurements.

http://video.ucar.edu/mms/image/samsi2014_enric_aguilar2.mp4 - Enric Aguilar gave a talk on problems in some typical data sparse non-N. American / European series.

http://video.ucar.edu/mms/image/samsi2014_finn_lindgren.mp4 - Finn Lindgren provided a talk on spatial statistical aspects.

Monday, June 30, 2014

Global Land Surface Databank: Version 1.0.0 Release

The International Surface Temperature Initiative is pleased to release version 1 of a new monthly dataset that brings together new and existing sources of surface air temperature. Users are provided a way to more completely track the origin of surface air temperature data from its earliest available source through its integration into a merged data holding. The data are provided in various stages that lead to the integrated product. 

This release is the culmination of three years effort by an international group of scientists to produce a truly comprehensive, open and transparent set of fundamental monthly data holdings. The databank has been previously available in beta form, giving the public a chance to provide feedback. We have received numerous comments and have updated many of our sources. 

This release consists of:
  • Over 50 distinct sources, submitted to the databank to date in Stage 0 (hardcopy / image; where available), Stage 1 (native digital format), and Stage 2 (converted to common format and with provenance flags).
  • All code to convert the Stage 1 holdings to Stage 2.
  • A recommended merged product and several variants which have all been built off the Stage 2 holdings. 2 ASCII formats are provided (ISTI format, GHCN format), along with a CF Compliant netCDF format.
  • All code used to process the data merge, along with statistical auxiliary files.
  • Documentation necessary to understand at a high level the processing of the data, including the location of the manuscript published in Geoscience Data Journal.
The entire databank can be found here and the merged product is located here. Earlier betas are also found here. Because the databank is version controlled, we welcome any feedback. We will be providing updates on the blog regarding any new releases.
  • For more information, please visit our website: www.surfacetemperatures.org
  • General Comment? Please email general.enquiries@surfacetemperatures.org

Location of all stations in the recommended version of the Stage Three component of the databank. The color corresponds to the number of years of data available for each station.

Station count of the recommended merge by year from 1850-2010. Databank stations in red compared to GHCN-M, version 3 in black.


Saturday, June 28, 2014

Understanding the effects of changes in the temperature scale standards through time

Since records of surface temperature started being made there have been iterations of the fixed points standards used by national metrological institutes (that is not a typo). Assuming that all meteorological measurements through time have been made to such standards (which may be a considerable stretch) this would have imparted changes to the records that are not physical in origin. As part of meteomet efforts have been made to understand this. It is a relatively small effect compared to effects of other long recognized data issues. Nevertheless it is important to properly and systematically consider all sources of potential biases as exhaustively as possible.

The work itself was led by Peter Pavlasek of the Slovak Institute of Metrology. His introduction is reproduced below:
Temperature is one of the main quantities measured in meteorology and plays a key role in weather forecasts and climate determination. The instrumental temperature recordings now spans well over a century, with some records extending back to the 17th century, and represents an invaluable tool in evaluating historic climatic trends. However, ensuring the quality of the data records is challenging, with issues arising from the wide range of sensors used, how the sensors were calibrated, and how the data was recorded and written down.  In particular, the very definition of the temperature scales have evolved. While they have always been based on calibration of instruments via a series of material phase transitions (fixed points), the evolution of sensors, measuring techniques and revisions of the fixed points used has introduced differences that may lead to difficulties when studying historic temperature records. The conversion program here presented deals with this issue for 20th century data by  implementing a proposed mathematical model to allow the conversion from historical scales to the currently adopted International Temperature Scale of 1990 (ITS-90). This program can convert large files of historical records to the current international temperature scale, a feature which is intended to help in the harmonisation processes of long historic series. This work is part of the project “MeteoMet” funded by the EURAMET, the European association of National Institutes of Metrology, and is part of a major general effort in identifying the several sources of uncertainty in climate and meteorological records.

Michael de Podesta, who has served on the steering committee since ISTI's inception, reviewed the software for ISTI and had the following summary:
Assuming that calibration procedures immediately spread throughout the world – homogenisation algorithms might conceivably see adjustments in 1968, with smaller adjustments in 1990.
 
If undetected, the effect would be to create a bias in the temperature record. This is difficult to calculate since the bias is temperature dependent, but if the mean land-surface temperature is ~10°C and if temperature excursions are typically ±10 °C then one might expect that the effect to be that records prior to 1968 were systematically overestimated by about 0.005 °C, and records between 1968 and 1990 by about 0.003 °C.

Michael's full summary which includes some graphical and tabular summaries can be found here.

The code package is a windows operating system based package. It is available here.

Wednesday, June 4, 2014

Paper describing benchmarking concepts in OA review

Just briefly to note that a discussion paper is now open for comment authored by the members of the benchmarking working group. This paper discusses the concepts and frameworks that will underpin all aspects of the benchmarking and assessment exercise. Its open to review until July 30th. Please do, if you have time and inclination, pop along and have a read and provide a constructive (!) review. The discussion site is at http://www.geosci-instrum-method-data-syst-discuss.net/4/235/2014/gid-4-235-2014.html .

Also, watch this space at the end of this month for exciting developments on the first pillar of the ISTI framework - the databank.

Finally, we are rapidly hurtling towards the SAMSI/IMAGe/ISTI workshop on surface temperatures and their analyses. Its going to be a busy few weeks so expect this blog to be somewhat less moribund than of late ...

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 https://www2.image.ucar.edu/event/summerprog.surfacetemps

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 surfacetemperatures.org). 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:
Spain
Poland
Canada
Switzerland
Australia
Tropics
Italy
Central Europe
Russia
Slovenia
Netherlands
UK
Austria
USA

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:

https://docs.google.com/spreadsheet/ccc?key=0Al6ocsUAaINSdHpTREJzVkRZUTdfVjNPRlh0Q1V3WUE&usp=sharing#gid=0

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

Kate

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.