GHCND - this was using just the HCN over the US, but we've now expanded this to include the GSN and so have world wide coverage. There is a risk that by using these data we are including stations which have significant inhomogeneties in them. However, in regions with other data sources, the effect should be minimised as a result of the other stations present. And in regions with no other data, having some data is better than none!
ACRE - we have adapted how this dataset is processed by Climpact2. As few stations will have overlaps with the reference period we are using (1961-90 by default) the quality control removes these stations, and so no indices are calculated - even those where the reference period isn't used. We now use a temporary reference period for each station and remove the indices which rely on it at a later stage.
Arabian, West African & South African data - these have been calculated using a more recent reference period (1981-2010). Again, we've adapted how these are handled to make sure as many stations are retained and those requiring the base period are removed.
What our intention is that we will release a version for a 1981-2010 reference period - where this situation is reversed. Of course, for raw data where the indices are calculated using Climpact, this isn't a problem. And for ECAD, LACAD and SACAD we can revert to the underlying daily data from EOBS, "LAOBS", and "SAOBS" and recalculate the indices.
We are continuing to source data - over Brazil, China, India, Iran, Japan, and Mexico - and also hope to obtain more data over south-east Asia in due course. We have set a deadline of June 2019 for data submissions to allow the finalisation of the paper.
The latest station distribution plots are below. This time we're showing the annual coverage and also for one of the months - as these tend to have more stations pulled through. The reason for this is that there are data presence requirements on a monthly and annual basis - and it is more likely to have insufficient data to calculate an annual quantity, than to calculate a monthly quantity.
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| Fig 1 - Consecutive Dry Days - Annual |
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| Fig 2 - Consecutive Dry Days - Monthly |
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| Fig 3 - Minimum Tmin - Annual |
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| Fig 4 - Minimum Tmin - Monthly |
In some cases the data that have been kindly provided only contain the annual indices, and so the coverage is different between annual and monthly maps shown below.
And here are the trend plots (simple linear values) for the same indices, also monthly (January and July) and annual. We note that the colour scales are the same for the annual and monthly maps - which we will reassess and adjust in future runs.
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| Fig 5 - trends for CDD, annually, in January and in July |
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| Fig 6 - trends for TNn, annually, in January and in July |
