Precipitation (rainfall) information has traditionally been derived from rain gauge records. Rain gauges directly measure the rainfall at a certain point, and if installed appropriately can provide excellent data. However, estimating rainfall between rain gauges can be a difficult process, especially if distances are large or elevations differ.
XRain by contrast provides data based on satellite rainfall measurements. This is particularly helpful where rainfall information is otherwise not available (such as in remote areas or developing countries) or where it is difficult to access. XRain data is even available over oceans, meaning islands are covered.
XRain provides the following information, based on data from 2000 to 2020 (inclusive):
- Monthly rainfall totals: mean, maximum, 75th percentile, median, 25th percentile, minimum
- Number of days of precipitation in a month
- Annual totals
For flood modelers, XRain provides high intensity rainfall information, otherwise known as design rainfall or extreme rainfall. Specifically, it provides a depth-duration-frequency (DDF) or intensity-duration-frequency (IDF) table for your site. Durations from 1 hour to 18 weeks are covered. See an example of the data available.