NORDHOM

Project description

NORDHOM - Nordic collaboration on establishing long-term homogeneous climate data records.
Phase 2 2015-2016

Background

Analysis of climate variability and change demands access to long term high-quality instrumental climate records. Such series are however often affected by inhomogeneities (artificial shifts) due to changes in the measurement conditions (relocations, instrumentation, change in environment, etc.). These changes may have the same magnitude or even exceed the multidecadal climate signal. When studying long-term variations, trends or cycles in climate a direct analysis of raw data series can therefore lead to wrong conclusions about climate variability and change.

To deal with this problem homogenization procedures have been developed for detecting and adjusting inhomogeneities. Several methods exist. COST Action ES0601 HOME made a comparison of the methods most commonly used applying benchmark datasets with known synthetic inhomogeneities.

The climate services at the Nordic NMHSs have a long profound tradition in cooperation on activities having common interest at all institutes. One of the more successful activities within this collaboration was the NACD1-project carried out in the 1990’ies. The outcome of this project was the NACD data set (1890- ) that was continued as the Nordic Climate Dataset (NkDS). This dataset consists of high quality long term climate series. In NACD the series for important climate elements were tested for homogeneity and in many cases adjusted for detected inhomogeneities. All Nordic institutes applied the same method for this analysis, namely the SNHT method developed at SMHI by Hans Alexandersson.

Since the mid-1990’ies there have been little systematic homogenization effort at the Nordic Meteorological Institutes. As a result of the above mentioned COST Action this important activity has been highlighted and there are concrete plans to establish new homogenization procedures at least at FMI, MET Norway and SMHI.

At an expert meeting held at Met Norway 3. – 4. December 2012 national plans and a possible Nordic collaboration applying common tools and procedures were discussed. The conclusion was that the national activities would profit from a Nordic cooperation. Phase 1 of the collaboration lasted 2013-2014, and is now ended. The next paragraphs presents possible activities for phase 2 where collaboration will be a support to the national activities and where exchange of data and knowledge will improve the quality of Nordic long term climate series. The focus is on synergetic activities where significant results should be obtained within a time frame of two years.

Deliverables transferred from phase 1

Deliverable D1.3 Datasets of monthly mean temperature and precipitation sum for homogeneity testing

Responsible: all

Deliverable ready: Q2-2015, done.

Specification of stations and time periods to use in homogenization work on the wiki-site. The raw-data files in Home-R format together with the network file will be uploaded to the wiki page. Norway still has to add temperature data. The Baltic states will also add data where possible.

Deliverable D1.4.1 Upload of metadata to the web

Responsible: All

Deliverable ready: Q2-2016

Uploading of metadata to wiki-site and on the web page at the end of the project Q4-2014. This metadata describes the stations used in the homogenization and the start year and stop year of the timeseries. Erik will write an example for Sweden and send to the other participants.

Deliverable D1.5 Nordic dataset of homogenized monthly series of mean temperature and precipitation sum

Responsible: all

Deliverable ready: Q4-2016

Homogenized data in Home-R format made available on the NORDHOM wiki-site (internal) and on the NkDS web-site (external). Sweden 1860-2015 for temperature and precipitation. Finland 1890-2013 for temperature and 1890-2013 for precipitation. Norway 1896-2015 for precipitation and 1920-2008 for temperature. Different methods will be used for precipitation which have to be documented.

Deliverable D1.5.1 Baltic dataset of homogenized monthly series of mean temperature and precipitation sum

Responsible: Baltic states

Deliverable ready: Q4-2016

Homogenized data in Home-R format made available on the NORDHOM wiki-site (internal) and on the NkDS web-site (external).

Deliverable D1.6 Re-launch of NkDS with homogenized data

Responsible: SMHI

Deliverable ready: Q4-2016

Data from D1.5 consisting of homogenized climate data series of monthly mean temperature and precipitation sum in NkDS format as a parallel dataset to the original unhomogenized quality controlled NkDS.

Deliverable D2.5 Publish what we have done with monthly data in an article describing the work of project phase 1 (2012-2014).

Responsible: all

Deliverable ready: Q4-2016

Together write a short article to document and make the international community aware of our work. This will be transferred to phase 2.

WP 1: Reference climate data sets

A reference data set consisting of homogeneous data series is the basis for all homogeneity testing. Establishing a common Nordic reference data set will increase the robustness of the national homogeneity analyses, particularly in the border regions and areas with sparse data coverage. The reference data set will be merged from the national reference data sets.

With the user needs focusing on daily data series, the second phase of the Nordhom project is a logical step forward.

Deliverable D11.1 Datasets of daily temperature and precipitation for homogeneity testing

Responsible: all

Deliverable ready: Q2-2016

Specification of stations and time periods to use in homogenization work on the wiki-site.

The raw-data files in Home-R format together with the network file will be uploaded to the wiki page. Mean, max and min data for temperature.

Deliverable D11.2 Nordic dataset of homogenized daily series of temperature

Responsible: all

Deliverable ready: Q4-2016

Homogenised daily mean, max and min temperature series 1960-2015 made available on the NORDHOM wiki-site (internal) and on the NkDS web-site (external). Precipitation is more complicated and is excluded at this stage.

WP2) Common methods for daily homogeneity testing and adjustment for inhomogenieties.

One of the outcomes of the COST HOME Action was open source software (in R) for homogeneity analysis. We suggest applying this software as a common (reference) method within the Nordic countries in practice and agreeing general principles of using metadata information. This will ensure consistent analysis within the Nordic NMHSs and also be in line with ongoing homogenization work elsewhere in Europe.

The national services will be responsible for analysis of their own climate records. In the border regions cooperation is needed to secure consistent analysis. Establishing common rules and specifications for identifying homogeneity breaks and calculating adjustments will be necessary.

Deliverable D12.1 Joint methodology and strategy for daily homogeneity testing and adjustment

Responsible: met Norway

Deliverable ready: Q2-2016

We have a draft strategy with methods and their performance, shortcomings, restrictions etc. for homogenization of daily values.

Description of SplidHom and MASH, version in use, instructions for installation, use etc. available at wiki-site.

Deliverable D12.2 Publish what we have done with daily data in an article describing the work of project phase 2 (2015-2016)

Responsible: Sweden

Deliverable ready: Q2-2017

Together write a short article to document and make the international community aware of our work in phase 2 (2015-2016). Depending on the progress of the work with daily homogenisation.

WP 3) Works shops, training seminars and dissemination.

Common understanding of the algorithms and software used for homogeneity analysis need proper training. Within NORDHOM training seminars and workshops for exchanging experiences and results will be organized. These might be co-organized with the European homogenization community.

In the second phase training on SplidHom and MASH should be organized.

Deliverable D13.1: Upload of documentation etc. on wiki-site

Responsible: all

Deliverable ready: Q4-2016

Continuous uploading of documentation etc. to keep wiki-site updated.

Deliverable D13.2: Updating Nordmet-website

Responsible: SMHI

Deliverable ready: Q4-2016

Continuous uploading of NORDHOM information, metadata, homogenized series etc. to keep external Nordmet-website updated.

Deliverable D13.3: Nordic workshops and training seminars

Responsible: all

Deliverable ready: Q4-2016

Gather for Nordic workshops one time a year and organize training in the softwares. Between physical meetings, video meetings will be arranged.

Practical training workshop on splidhom in Tarragona in Spain and/or MASH in Oslo? 2-3 days.

Also compare results of individual homogenisation of a common Nordic monthly dataset of temperature and precipitation. Maybe focus on the most northern part of Norway, Sweden and Finland.

Survey of timetable and deliverables

 

2015

2016

2017

Activities transferred from phase 1

1

2

3

4

1

2

3

4

1

2

 

D1.3 Datasets of monthly temperature and precipitation for homogeneity testing

x

X

 

 

 

 

 

 

 

 

 

D1.4.1 Upload of metadata to the web.

x

x

x

x

x

X

 

 

 

 

 

D1.5 Nordic dataset of homogenized monthly series of mean temperature and precipitation

x

x

x

x

x

x

x

X

 

 

 

D1.5.1 Baltic dataset of homogenized monthly series of mean temperature and precipitation

x

x

x

x

x

x

x

X

 

 

 

D1.6 Re-launch of NkDS with homogenized data

x

x

x

x

x

x

x

X

 

 

 

D2.5 Publish what we have done with monthly data in an article describing the work of project phase 1 (2012-2014).

x

x

x

x

x

x

x

X

 

 

 

Activities in phase 2

 

 

 

 

 

 

 

 

 

 

 

D11.1 Datasets of daily temperature and precipitation for homogeneity testing

x

x

x

x

x

X

 

 

 

 

 

D11.2 Nordic dataset of homogenized daily series of temperature

 

X

X

X

X

X

X

X

X

 

 

 

D12.1 Joint methodology and strategy for daily homogeneity testing and adjustment

x

x

x

x

x

X

 

 

 

 

 

D12.2 Publish what we have done with daily data in an article describing the work of project phase 2 (2015-2016)

x

x

x

x

x

x

x

x

x

X

 

D13.1: Upload of documentation etc. on wiki-site

x

x

x

x

X

X

X

X

 

 

 

D13.2: Updating Nordmet-website

x

x

x

x

x

x

x

X

 

 

 

D13.3: Nordic workshops and training seminars

x

x

x

x

x

x

x

X

 

 

 

Homogenization software used in the Nordhom project

Homer

Splidhom

MASH

AttachmentSize
Nordhom_phase 1_v3.pdf114.91 KB
Nordhom_phase_2_v6.pdf110.63 KB