Improved spatial and temporal coverage

Since the last post, more data have arrived and been included in the latest run of HadEX3.  These include temperature and rainfall over Canada and Chile, and rainfall over Australia.

With the Angular Distance Weighting gridding, these additions are starting to fill in the globe for some indices - those which have long correlation length scales.  However, our quest for further data is not over, and we are indebted to our colleagues around the world for their efforts in providing data and calculating the indices.

Station Distribution for TX90p (annual)

Station distribution for R10mm (annual)

The location of all the stations which currently contribute to HadEX3 for two example indices are shown above.  As is clear, we still have large gaps, in Africa and Asia, as well as parts of South America, but we are working on filling these in the next few months.  However, as always, if you are able to send daily Tx, Tn and Precipitation data, or know of collections we could use, please get in touch!

Trend in TX90p (annual)

Trend in R10mm (annual)

Using the preliminary data the above two panels show the linear trends in these two example indices.  These plots are automatically produced, so the colour-scales are not necessarily the best. What is also clear is that some stations in central-north Africa seem to have some unexpected values for TX90p which are influencing the region surrounding them.  These may be true measurements, but are in stark contrast to neighbouring regions.  Similarly over south-eastern Asia there are strong trends not occurring in neighbouring grid-boxes.  As these are preliminary plots, we are not commenting on the correctness, just that we should take a look and check.

 

Timeseries of TX90p, comparing HadEX3 with earlier products (and matching to HadEX2 coverage).

Timeseries of R10mm, comparing HadEX3 with earlier products (and matching to HadEX2 coverage)

 

What we can also do at this stage is compare the "global" average (land surface, where there are data) to previous products in the "Climdex Family".  Even at this point, with relatively large gaps in the spatial coverage, there is some agreement with HadEX2 (and more so when HadEX3 is coverage matched). For TX90p, as this is an index using a reference period, then GHCNDEX also matches relatively well.  However, for R10mm, although the short-timescale variation is reasonable, there is an offset to GHCNDEX, most likely due to different regions having data. This is also a likely cause for the "edge-effects" in the most recent years, as there are no stations in Asia and few in Africa post-2014 (see below).

HadEX3 stations for R10mm in 2005

HadEX3 stations for R10mm in 2015