Predictions, Projections, or Portents - Weather and Climate Modelling
(VIRTUAL) October – December 2022
Instructors: Simon J Mason (lead) and Ángel Muñoz, International Research Institute for Climate and Society, Columbia Climate School
Weather and climate forecasting involves use of some of the most powerful computers in the world, and yet there is a widespread perception that forecasts are highly inaccurate, and some people believe that models are so problematic that they undermine the basis for belief in climate change projections, for example. The weather is, generally, inherently impossible to predict beyond a few days, and there are some serious limitations to climate models, so what basis is there for predicting far into the future, and how much can we believe it?
This workshop will take a sober approach to addressing these questions. It will take a largely mathematics- and physics-lite approach to understanding the basic principles of how weather forecasts are made, and how those approaches are adapted, and sometimes modified completely, to predict further into the future. Forecasts at timescales of hours, days, weeks, months, years, decades, and centuries will discussed. The workshop will spend some time considering how the quality of forecasts can be measured to highlight some ways in which it is possible to make forecasts look far better than they really are, and to highlight why some seemingly intuitive ways of evaluating forecasts can encourage the forecaster to make bad predictions! Using this information, the workshop will also evaluate some non-official sources of forecasts, recognizing what is valid whilst exposing what is more problematic.
- The concept of chaos: Why is it theoretically impossible to make accurate weather predictions, and how far into the future can accurate forecasts be made?
- The importance of timescale: How might it be possible to forecast further into the future, i.e., how is it possible to make forecasts weeks, months, and longer into the future when weather forecasts become so inaccurate so quickly? We will cover timescales from minutes to centuries in advance.
- The concept of uncertainty: How can the inherent uncertainty in forecasts be (a) estimated and (b) communicated?
- The importance of good data: How important is it to know what the weather is like now? How much can we tell from weather observations on the ground? And how do we know what is going on above the ground, or in the sea? How useful are satellites? How is all the data accessed in the first place?
- Weather and climate models: How do weather and climate models work, and how do they differ? What are the different types of climate models? Are climate models realistic, and how serious are their imperfections? What can be done to try to compensate for the model imperfections? Do we even need to use such models – are some simpler ways of making forecasts that are almost as good, or possibly even better?
- Forecasting impacts: How do we translate forecasts of weather and climate phenomena into forecasts of impacts that we may care more about, such as floods, health risks, crop failures, pests, power shortages, or perhaps even civil unrest or migration?
- Forecast verification? What can we forecast well, and what not so well? How far into the future? Are there good and bad ways for measuring how good or bad forecasts are? How do some forecasters cheat to make their forecasts look better than they really are? How do unbiased estimates of forecast quality compare with your own perceptions of how good or bad the forecasts are? Can we estimate how economically valuable forecasts are?
- Alternative forecasting systems: Can the weather and climate be predicted using the phase of the moon, or by cyclic periods of droughts and floods, or by other observations of nature, or by consulting the long-range weather forecasts in the Farmers’ Almanac. Is there any validity to folk-lore methods of prediction?
Who this workshop is intended for: This workshop is intended for individuals who are looking to gain a basic understanding of how weather and climate forecasts are made, how to interpret them correctly, what their limitations are, and how much credence to place in them. Some basic understanding of climate science would be useful, but not essential. A small amount of mathematics and statistics will be used, but again the level of comfort in these fields that is required will be minimal. A basic understanding of maps and graphs will be needed, but if needed some simple introductory materials can be provided that participants can review before the course commences. The workshop will be accessible to learners from different backgrounds and will provide foundational knowledge about how weather and climate are predicted.
Learning modalities: This workshop will be offered in a virtual format via Zoom. It will feature of mix of lectures, discussion, and audio/visual materials. Guest speakers will share their practical knowledge and experience as well. A small amount of additional reading material will be provided for participants who need more background to understand better the material presented, and some video material can be pointed to. Some limited additional material can be referenced for participants who wish to learn more about the topics. Guest speakers will share their practical knowledge and experience as well.
Please note that all workshops are taught in English. Proficiency in written and spoken English is required.
Schedule: VIRTUAL October – December 2022. Session 1 will be 2 hours in length, and all subsequent sessions will be 2 hours and 10 minutes.
Session 1: Thursday, October 27, 5.30-7.30pm
Session 2: Thursday, November 3, 5.30-7.40pm
Session 3: Thursday, November 10, 5.30-7.40pm
Session 4: Thursday, November 17, 5.30-7.40pm
Session 5: Thursday, December 1, 5.30-7.40pm
Session 6: Thursday, December 8, 5.30-7.40pm
Session 7: Thursday, December 15, 5.30-7.40pm