Stratospheric Network for the Assessment of Predictability (SNAP)

Forecasting the weather from days to two weeks in advance has typically focused on the troposphere, the layer of the atmosphere closest to the ground. A typical weather forecast first attempts to estimate what the atmosphere is like now, and then extrapolates forward in time, using a complex model of the atmosphere based on the basic physical laws of motion. Over the last 15 years, evidence has been growing that different parts of the atmosphere and Earth system can also be exploited to improve weather forecasts. One of these regions is the stratosphere, the layer directly above the troposphere. Because, temperatures increase with height in the stratosphere, winds and weather systems are quite different, and a distinct community of scientific researchers who study the stratosphere exists around the world. Through the work of this community, many weather forecasting centres have been encouraged to look to the stratosphere to improve their weather forecasts and have been modifying their weather forecasting models accordingly. What has been missing, however, is a concerted effort to understand how best to make use of the stratosphere to improve weather forecasts and to determine how much weather forecasts might benefit.

This proposal will fund a new international scientific network which will bring scientists from around the world together to study the stratosphere and how it might be used to improve weather forecasts. The network is made up of scientists from universities and weather forecasting centres around the world and is supported by two other international scientific research bodies. The network will allow scientists to come together to discuss current research in this area and to plan and carry out a new experiment which will compare the stratosphere and its impact on weather forecasts in their weather forecasting models. At the end of the research project, the network members will work together to produce a report which will provide guidance to all weather forecasting centres on the use of the stratosphere for weather forecasting.

The key beneficiaries of the research will be the weather forecasting centres who participate in the network and will gain valuable insight into how to maximise potential gains in tropospheric predictability from the stratosphere. Since they will be part of the network, it will be very easy to communicate the key results of the project to them through the two project workshops and the report that the network will produce. In the UK, the Met Office is a core member of the network and will benefit strongly from the research which meets their own strategic goals as expressed in their letter of support.

Since all of the weather forecasting centres provide their forecasts to a broad range of governmental and non-governmental customers, improving the skill of weather forecasts provides a direct way that research in this area can benefit the UK and other economies and general public well-being. It is worth noting that previous research has suggested that some of the most recent periods of disruptive weather in the UK, particularly the extreme cold conditions in December 2009, have been linked in part to stratospheric weather.