Statistical post-processing techniques for weather, climate, and hydrological forecasts are powerful approaches to compensate for effects of errors in model structure or initial conditions, and to calibrate inaccurately dispersed ensembles. These techniques are now an integral part of many forecasting suites and are employed in many end-user applications such as wind energy production or flood warning systems. Many of these techniques are now flourishing in the statistical, meteorological, climatological, hydrological, and engineering communities. The methods range in complexity from simple bias correction up to very sophisticated distribution-adjusting techniques that take into account correlations among the prognostic variables.

Conversely, there is more and more interest in building probabilistic forecasts based on various sources of information at various timescales, for instance data-driven nowcasting with numerical weather prediction models. In this context, statistical techniques are also used to provide reliable forecasts.

This special issue gathers contributions on theoretical developments in statistical post-processing and blending techniques, and on evaluations of their performances in different practical applications oriented toward environmental predictions.

2019 will be the hundredth anniversary of a new start of international scientific collaborations after the First World War, in particular with the creation of the International Union of Geophysics and Geodesy, its associations, and national committees. It is a remarkable opportunity to celebrate the accomplishments of nonlinear geophysics during this past century, as well as to look forward to the challenges of the next century. It is also a remarkable opportunity to think about NPG's revival and testifies to its importance. NPG is therefore inviting the EGU Richardson medallists to contribute to this issue.

Please note that this special issue is only for invited contributions.

The issue is open to any aspect of the subject including the present accuracy of coastal, regional and global tide models; tidal dissipation and its role in geophysics; internal tides and their role in mixing the ocean and in the global ocean circulation; secular changes in tides; and new techniques for measuring tides and analysing the data. The issue also welcomes new findings on earth and atmospheric tides, the role of tides in the origin of life on earth, palaeotides, lake and planetary tides and many other aspects of tides.

The launch of the special issue coincides with the upcoming 100th anniversary of the founding of the Liverpool Tidal Institute (LTI). The LTI was established in 1919 and for many years was the world centre for knowledge of the tides, with Joseph Proudman taking the lead in dynamical theories and Arthur Doodson in the analysis of tidal information from around the world, and tidal prediction. The year 2019 is also the 100th anniversary of the International Union of Geodesy and Geophysics (IUGG), which will meet in Montreal during 9–18 July 2019. The Montreal IUGG will include a Joint Symposium on Tides (with IAPSO as the lead Association) that will be open to all of the aspects of tidal science mentioned above. The symposium will provide a fitting recognition of the anniversaries of both the LTI and IUGG. Contributors to the symposium would be encouraged to write up their work for publication in the special issue.

The special issue is open for contributions now and will stay open until the end of 2019, thereby taking advantage of new findings presented at the IUGG. It is open to any contributor, not only those with links to the LTI or attending the IUGG in Montreal.

Statistical post-processing techniques for weather, climate, and hydrological forecasts are powerful approaches to compensate for effects of errors in model structure or initial conditions, and to calibrate inaccurately dispersed ensembles. These techniques are now an integral part of many forecasting suites and are employed in many end-user applications such as wind energy production or flood warning systems. Many of these techniques are now flourishing in the statistical, meteorological, climatological, hydrological, and engineering communities. The methods range in complexity from simple bias correction up to very sophisticated distribution-adjusting techniques that take into account correlations among the prognostic variables.

Conversely, there is more and more interest in building probabilistic forecasts based on various sources of information at various timescales, for instance data-driven nowcasting with numerical weather prediction models. In this context, statistical techniques are also used to provide reliable forecasts.

This special issue gathers contributions on theoretical developments in statistical post-processing and blending techniques, and on evaluations of their performances in different practical applications oriented toward environmental predictions.

2019 will be the hundredth anniversary of a new start of international scientific collaborations after the First World War, in particular with the creation of the International Union of Geophysics and Geodesy, its associations, and national committees. It is a remarkable opportunity to celebrate the accomplishments of nonlinear geophysics during this past century, as well as to look forward to the challenges of the next century. It is also a remarkable opportunity to think about NPG's revival and testifies to its importance. NPG is therefore inviting the EGU Richardson medallists to contribute to this issue.

Please note that this special issue is only for invited contributions.

The issue is open to any aspect of the subject including the present accuracy of coastal, regional and global tide models; tidal dissipation and its role in geophysics; internal tides and their role in mixing the ocean and in the global ocean circulation; secular changes in tides; and new techniques for measuring tides and analysing the data. The issue also welcomes new findings on earth and atmospheric tides, the role of tides in the origin of life on earth, palaeotides, lake and planetary tides and many other aspects of tides.

The launch of the special issue coincides with the upcoming 100th anniversary of the founding of the Liverpool Tidal Institute (LTI). The LTI was established in 1919 and for many years was the world centre for knowledge of the tides, with Joseph Proudman taking the lead in dynamical theories and Arthur Doodson in the analysis of tidal information from around the world, and tidal prediction. The year 2019 is also the 100th anniversary of the International Union of Geodesy and Geophysics (IUGG), which will meet in Montreal during 9–18 July 2019. The Montreal IUGG will include a Joint Symposium on Tides (with IAPSO as the lead Association) that will be open to all of the aspects of tidal science mentioned above. The symposium will provide a fitting recognition of the anniversaries of both the LTI and IUGG. Contributors to the symposium would be encouraged to write up their work for publication in the special issue.

The special issue is open for contributions now and will stay open until the end of 2019, thereby taking advantage of new findings presented at the IUGG. It is open to any contributor, not only those with links to the LTI or attending the IUGG in Montreal.