Säätilamallit

Säätilamallit, also known as weather models, are sophisticated computer programs that simulate the Earth's atmosphere to forecast future weather conditions. These models divide the atmosphere into a three-dimensional grid and use fundamental physical laws, such as those governing fluid dynamics and thermodynamics, to calculate how variables like temperature, pressure, wind, and humidity will change over time.

The process begins with collecting vast amounts of current weather data from various sources, including weather stations, satellites, buoys, and aircraft. This data serves as the initial state for the model. The model then iteratively solves complex mathematical equations for each grid point, predicting the state of the atmosphere at future time steps.

Different weather models exist, varying in their resolution (the size of the grid cells), the physical processes they incorporate, and the geographic area they cover. Global models aim to predict weather patterns worldwide, while regional models focus on smaller areas with higher detail. Numerical weather prediction (NWP) is the overarching term for the science of forecasting weather using these mathematical models.

The accuracy of these models has improved significantly over the decades due to advancements in computing power, data assimilation techniques, and a deeper understanding of atmospheric physics. However, weather forecasting remains an inherently challenging task due to the chaotic nature of the atmosphere, meaning small initial errors can lead to large differences in forecasts over time. Ensemble forecasting, where multiple model runs with slightly varied initial conditions are performed, is a common technique to assess forecast uncertainty and provide a range of possible outcomes.