Report on validation of CIIs

As part of EUPORIAS, we have analysed seasonal forecasts of climate information indices. This final deliverable of work package 22 highlights opportunities and challenges of working with seasonal forecasts of indices.

Seasonal forecasts of indices are challenging to produce and analyse. Common and publicly available tools developed in WP22 for download, bias correction, computation of indices, and evaluation of such forecasts are key to capacity building within and beyond the project.

Forecasts of indices are generally only as skilful as those of the underlying variables the indices are derived of1. Also, skill varies in space, time, and many other factors. We have developed a publicly available web platform2 for users to explore variability in forecast skill and identify opportunities for skilful and thus useful forecasts.

Overall, predictability for Europe is limited and forecasts of indices are only marginally skilful. This current report presents examples for various sectors such as hydrology, viticulture, and energy showing that it is very difficult to derive decision-relevant information from seasonal forecasts in Europe due to the lack of skill. Shorter-range forecasts on the other hand may add value thanks to their enhanced forecast quality as demonstrated with heat-related mortality forecasts3.

In the context of the LEAP prototype, it has been shown that estimates of humanitarian needs for Ethiopia with forecasts from May are as good as post-hoc estimates of needs based on satellite data available in October after the growing season. Thereby, humanitarian needs in Ethiopia could be estimated four months earlier than currently. This illustrates that while the climatic conditions can be difficult to forecast, forecasts of impacts dependent of these conditions can have considerable value.