FREQUENTLY ASKED QUESTIONS

"What is the importance of sea ice observations for polar prediction?"

Observations are an important element of polar prediction. Observations provide input for data models and are also used to evaluate predictions.

Dr. Donald K. Perovich, ERDC-CRREL, PPP Steering Group Member

"Why should climate researchers be interested in polar weather forecasting?"

Climate prediction is an initial-condition problem in a similar way as weather forecasting is. The progress in weather forecast initialisation from better observations, data assimilation and dynamical models will benefit climate forecasts given that the tools used are very similar. In this context, the PPP is relevant to both the weather and climate forecasting communities.

Dr. F.J. Doblas-Reyes, ICREA Professor at the Catalan Institute of Climate Sciences (IC3), Former PPP Steering Group Member

"Do interactions between atmosphere, ocean & sea ice matter for polar prediction?"

The atmosphere, ocean and sea ice interact through a range of physical processes and mechanisms, from the small-scale opening of leads in the pack ice to large scale impacts of the retreating ice cover. Due to the strong contrasts in polar regions, capturing these interactions can be crucial for making skillful predictions. For example, the sea ice cover acts as a barrier between the atmosphere and the ocean whose temperatures often differ by more than 20°C in winter. Rapid opening of the ice cover can result in the release of large amounts of heat and moisture with important impacts on weather forecasts.

Dr. Gregory Smith, Environment Canada, PPP Steering Group Member

"Why do we need a polar prediction project?"

The benefit of weather and environmental prediction from hours to seasons in Polar Regions has been to some extent delayed, due to the higher priority of forecasting in the more densely populated mid-latitude and tropical regions. Recent and remarkable environmental changes at higher latitudes, like sea-ice cover trend, combined with increasing governmental and socio-economic interests require now better weather and environmental forecasts in the Polar Regions. The Polar Prediction Project of the World Weather Research Programme will accelerate our ability to make reliable forecasts in Polar Regions.

Dr. Gilbert Brunet, WWRP/SSC Chair, Environment Canada

"What forecast ranges is PPP going to address?"

The Polar Prediction Project deals with daily, weekly, monthly and seasonal forecasts. This necessity to consider these forecast ranges can be best illustrated using shipping in the Arctic as an example: Safe shipping through the sea ice requires skilful daily and weekly forecasts to anticipate treacherous environmental conditions such as pressure ridging of the sea ice cover; monthly and seasonal forecasts will provide longer-term information that can be used to decide whether ships shoukd be opting for Arctic sea routes at all. 

Prof. Dr. Thomas Jung, Alfred Wegener Institute, Chair of PPP Steering Group

"How can we determine the quality of a forecast?"

Determining the quality of forecasts, usually called forecast verification in meteorology, can be a very complex process of comparing forecasts with relevant weather observations. There is a saying that nothing is as difficult as forecasting the weather, however there is another saying that nothing is as difficult as properly and reliably evaluating the quality of weather forecasts. The ways to depict and convey forecast quality to the general public need to be done in simple terms, whereas for professional meteorologists the verification measures are often highly sophisticated statistical metrics.

Dr. Pertti Nurmi, Finnish Meteorological Institute, Former PPP Steering Group Member

"Will PPP improve the forecasting of extreme Arctic weather?"

The polar regions are not particularly windy, as they are outside the main storm tracks. Extreme events do intermittently occur in certain regions. One example is polar lows.

These meso-scal hurricane-like cyclones form in October to April when very cold air flows southwards over the open sea water. The winds are rarely extreme (15-20 m/s), but in combination with intense snow-fall and freezing sea-spray, the weather is dangerous. Being prepared is difficult, as they develop very quickly (12-24 hours) in areas with few observations. Some can presently be predicted well, but many are seriously missed. Satellite observations (e.g. IASI) in combination with more frequent or regular observations can improve, and it is good hope that PPP will boost the quality of polar low predictions.    

Prof. Dr. Trond Iversen, ECMWF, MET Norway, Former Member of PPP Steering Group

"Why is it so challenging to improve numerical weather prediction models in polar regions?"

Small-scale processes such as turbulence and clouds are difficult to get right in models. Most of the descriptions are based on process knowledge from studies using observations at lower latitudes and are sometimes not well suited for polar conditions. Special conditions found over sea-ice covered ocean are long periods with weak atmospheric activity in a shallow layer in strong interaction with the surface. Models tend to have problems in these conditions and PPP assists in coordinating co-located process observations from in the ocean, through the sea-ice and atmosphere that would help model development and evaluation. 

Prof. Dr Gunilla Svensson, Department of Meteorology and  Bolin Centre for Climate Research, Stockholm University, PPP Steering Group Member

"What is needed the most to significantly improve weather prediction models?"

We know that clouds can look beautiful but sometimes they make us feel cold. So far, clouds are the most significant source of uncertainty in weather prediction models. We still need to learn more on their physical properties, in order to describe them accurately in our models.

Prof. Dr. Mikhail Tolstykh, Institute of Numerical Mathematics/Russian Academy of Sciences and Hydrometcentre of Russia, Member of PPP Steering Group

"Why should early career scientists be interested in polar prediction?"

Polar weather prediction has received much attention over recent years. The rapid increase in industrial activity and tourism in the Arctic means it is likely that the demand for forecasts from stakeholders is likely to continue to grow. This growth in demand makes this subject area a good place to start a career and an exciting topic to research.

Dr. Jonathan Day, University of Reading, PPP Steering Group Member

"What does the term 'new Arctic' imply?"

The "new Arctic" is a term used to capture the view that large changes observed in the Arctic climate system in recent decades are both dramatic and unlikely to reverse in the foreseeable future. The changes are principally associated with warming over land and the unprecedented decline in summer sea ice extent (half what it was 40 years ago). Other changes include loss of permafrost, lengthened growing seasons, northern migration of plants and animals from non-Arctic climate zones, etc. From a scientific perspective, it describes an upset in the normal Arctic balance of physical and chemical processes. For example, the lost sea ice has opened up vast regions of the Arctic Ocean to the growth of ocean surface waves. This increased fetch has changed the wave climate of the Arctic which further increases sea ice loss and coastal erosion.

Dr. Christopher Fairall, ESRL, NOAA, PPP Steering Group Member

"What does hosting the International Coordination Office mean to the Alfred Wegener Institute?"

Observations and modelling of the polar regions and research on polar prediction lie at the heart of the scientific activities at AWI. Hosting the International Coordination Office is part of our contribution to the realization of GIPPS, the WMO Global Integrated Polar Prediction System, and is of major importance to climate research at AWI.

Prof. Dr. Peter Lemke, Alfred Wegener Institute Bremerhaven, Germany, Former PPP Steering Group Member

"What is the role of observations in forecasting?"

Observations provide the starting point for any weather forecast. They are assimilated into the numerical modelling system to provide an initial state for the atmosphere. Forecasts are then calculated from this starting point. In the polar regions, a chronic shortage of observations and the difficulty of interpreting some satellite-based observations present a major challenge to weather forecasting systems.

Prof. Dr. Ian Renfrew, University of East Anglia, PPP Steering Group Member

"How far in advance can we predict September Arctic sea ice cover?"

Studies suggest potential skill in predicting September Arctic sea ice cover for one, or even two, years in advance. However, to realize this potential skill requires the development of reliable forecasting systems. Work is advancing in this area, but more is needed before we will routinely and reliably be providing skillful forecasts of Arctic sea ice conditions.  

Dr. Marika Holland, NCAR, Former PPP Steering Group Member

"Why is international collaboration needed?"

Weather and climate do not respect national boundaries, so to predict more than a short time ahead requires observations from other countries and regions. International collaboration is needed to gather and exchange observational data and products. This is done using systems arranged by the World Meteorological Organization (WMO). Similarly, international collaboration is essential for major research endeavours such as the Polar Prediction Project. Researchers from different countries, organizations and disciplines can share and build on their different expertise and knowledge, and they are all able to exploit both observational data, and computer model output, which can be very expensive to gather and produce.

Neil Gordon, WMO Consultant, New Zealand, formerly with ICO for Polar Prediction