Annual Seminar 2019

Over the past decade, substantial efforts have been devoted to elucidate how a changing climate will impact ENSO. At the same time, there have been continuous advances in ENSO monitoring and predictive capabilities. In this talk, we bring together both lines of work by discussing the performance of initialized ENSO predictions. Improved reanalyses data sets, real-time seasonal forecasts, and...

The Madden-Julian Oscillation is the dominant mode of sub-seasonal variability in the tropical climate system and a major potential source of predictability on sub-seasonal timescales. This presentation will review our current understanding of the MJO; the impacts of the MJO in the tropics and extra-tropics; the skill of weather and climate models in simulating the MJO; and conclude with some...

Unlike in vast areas of midlatitude ocean basins, the warm midlatitude/subtropical western boundary currents and associated oceanic frontal zones can potentially impact the overlying atmosphere. Multi-scale aspects of the impacts are overviewed in this presentation. Effective moisture supply from a warm current to individual cyclones and efficient restoration of near-surface atmospheric...

Processes occurring at the land surface impact weather and climate variability in a wide range of timescales from days to millennia, making land surface models a required component of both weather and climate prediction systems. Of special relevance is the role of land surface processes involving snow, soil water and vegetation in the amplification of extreme weather and climate anomalies,...

At high latitudes, the dominant physical processes are radically different from the mid-latitudes and the tropics. At the surface, the large-scale presence of snow and sea ice provides a potential source of predictability on sub-seasonal to seasonal time scales, but poses a difficult challenge for reliable observation, model representation and initialization. Likewise, the atmosphere over snow...

In recent years, user demand for forecasts that fill the gap between medium-range weather (up to 15 days) and long-range or seasonal
(3–6 months) forecasts has increased. Skillful subseasonal to seasonal prediction can support decision-making and help
optimizing resource management decisions.
Prediction at the S2S scale, however, is particularly challenging because it is both an initial value...

Sub-seasonal to seasonal (S2S) predictions of surface climate are crucial for a wide range of sectors. One of the promising areas that adds predictability on these timescales is the stratosphere, which has been found to play an important role in the predictability of surface weather on S2S timescales. The downward influence of the stratosphere onto the surface can lead to increased persistence...

This seminar will review statistical methods for verification of probabilistic forecast at the extended and seasonal range. Transparent statistical modelling frameworks will be presented for modelling the distributional properties of forecasts and observations. It will be shown how such frameworks can provide complete verification summaries and be used to diagnose predictability issues such as...