The Science behind Predicting the Weather

The scientific study of the atmosphere is known as meteorology. Prediction of the weather through application of the principles of physics and meteorology is known as weather forecasting. Experts in the field of meteorology save lives and property by providing timely warnings regarding events like tsunamis. The World Meteorological Organization (WMO) is a specialized agency of the United Nations for meteorology.

The modern age of weather forecasting began with the invention of the electric telegraph. This technology facilitated quick transmission of weather condition reports. The first public radio forecasts were made in the year 1922 from Marconi House, London. Farmers found these forecasts very useful.

Meteorologists use mathematical models of the oceans and the atmosphere to predict the weather. The atmosphere is like a fluid. Meteorologists apply the principles of fluid dynamics and thermodynamics to predict the weather. They are of the opinion that if they design an accurate mathematical model of the atmosphere (with all its complexities), they will be able to predict the weather accurately. Generally imperfect models result in inaccurate weather predictions.  

Partial differential equations (PDE) are used to simulate the atmosphere. It is very difficult to solve these equations correctly. Another challenge is that small errors grow with time. They double about every five days. Techniques like model output statistics (MOS) help in handling errors in numerical predictions. Ensemble forecasts have helped in dealing with the stochastic nature of weather processes. 

Some models use finite differences while some others use spectral methods to predict the weather. The horizontal domain of a model is either global or regional. The ideal gas law (pressure=density*temperature*gas constant) is used extensively by the meteorologists all over the world. 

Computer simulation (also known as computer modeling) has made weather prediction easier. Modern atmospheric models (computer programs that produce meteorological information at a given location) use primitive equations to predict the weather. Meteorologists use supercomputers to perform complex calculations involved in modern numerical weather prediction. Use of computers has extended the range and accuracy of weather forecasts. 

Weather observations obtained from radiosondes (installed in weather balloons) help meteorologists predict weather with adequate accuracy. Weather balloons sometimes reach the stratosphere (which is above the troposphere). Radiosondes measure variables like pressure, humidity, altitude, cosmic ray readings, geographical position (latitude/longitude), temperature, wind speed and wind direction. Weather reconnaissance aircrafts (like the Boeing WB-50D) are used to obtain atmospheric data. Weather satellites provide valuable information for meteorologists. 

Meteorology is a fascinating subject.