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Category: seasonal prediction

GloFAS-ERA5 reanalysis: River discharge ‘maps without gaps’ from 1979-present

GloFAS-ERA5 reanalysis: River discharge ‘maps without gaps’ from 1979-present

Contributed by Shaun Harrigan, ECMWF. In an ideal world we would have river discharge measurements for every river spanning many decades and updated in real time. We all know this is very far from reality with severe gaps in the global observing network (Lavers et al., 2019), and provides a fundamental challenge for hydrological monitoring and forecasting. A way forward pioneered in the field of meteorology and climate is to optimally combine available in situ and satellite Earth system observations…

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Can we foresee drought and its impacts?

Can we foresee drought and its impacts?

Contributed by Samuel J. Sutanto and Henny A.J. Van Lanen; Hydrology and Quantitative Water Management Group, Wageningen University, the Netherlands. The 2018 and 2019 droughts are still fresh in our memory, when extended areas in Europe suffered, once more, from extreme drought. Climate projection studies show that drought very likely will become more frequent. Similar to the 2015 drought (Van Lanen et al., 2016), impacts of the 2018 drought in Europe were tremendous and affected many sectors. For example, farmers…

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Is One Forecast Model Better Than Another?

Is One Forecast Model Better Than Another?

Blog post contributed by: Tim DelSole* The Sign Test Is one forecast model better than another? A natural approach to answering this question is to run a set of forecasts with each model and then see which set has more skill. This comparison requires a statistical test to ensure that the estimated difference represents a real difference in skill, rather than a random sampling error. Unfortunately, there are three problems with using standard difference tests: they have low statistical power,…

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“One thing you need to know about seasonal forecasts”

“One thing you need to know about seasonal forecasts”

Contributed by Rachel Bazile, Marie-Amélie Boucher and Chris White. “It is that they have no skill…” This is how Matt Newman from NOAA’s ESRL referred to seasonal forecasts in his opening presentation at the Second International Conference on Subseasonal to Seasonal (S2S) / Seasonal to Decadal (S2D) Prediction. Organized by NCAR, the meeting which was held from Sept. 17 to 21 in Boulder, Colorado, had gathered more than 300 international scientists from both the S2S and S2D prediction communities… but…

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Summer 2018 in Europe: did the EFAS seasonal outlook predict low river flows?

Summer 2018 in Europe: did the EFAS seasonal outlook predict low river flows?

— this post is jointly published on the blogs of HEPEX and the European Drought Centre — Contributed by Louise Arnal (ECMWF and University of Reading), Shaun Harrigan (ECMWF) & David Lavers (ECMWF). Summer 2018 in Europe was remarkable from a hydroclimate perspective, with large regions experiencing persistent dry conditions, very little to no rainfall for extended periods, a series of heatwaves with record-breaking temperatures and numerous wildfires (in the UK, Sweden, Greece, Spain, Portugal, Latvia and Germany, among others)….

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