Brief Rain Shower

In just a few moments the sky stirs to life with a simple, clean sprinkle of rain that runs along the roof and the little channels in the garden. You stand beneath your porch, enjoying the unexpected change to the afternoon weather, washing away all the week's worries down into the brown earth, changing the typical garden into a filter for your mind. One of the main uses of weather radar is to be able to assess the amount of precipitations fallen over large basins for hydrological purposes. For instance, river flood control, sewer management and dam construction are all areas where planners use rainfall accumulation data. Radar-derived rainfall estimates compliment surface station data which can be used for calibration. Satellite derived rainfall estimates use passive microwave instruments aboard polar orbiting as well as geostationary weather satellites to indirectly measure rainfall rates. The Quantitative Precipitation Forecast (abbreviated QPF) is the expected amount of liquid precipitation accumulated over a specified time period over a specified area. A QPF will be specified when a measurable precipitation type reaching a minimum threshold is forecast for any hour during a QPF valid period.If one wants an accumulated rainfall over a time period, one has to add up all the accumulations from each grid box within the images during that time.