Traditional Culture Encyclopedia - Weather inquiry - The unit of precipitation in weather forecast is "millimeter". What is the concept of "millimeter"?

The unit of precipitation in weather forecast is "millimeter". What is the concept of "millimeter"?

The precipitation in a certain period, the depth of rainwater gathered without any infiltration, evaporation or loss during this period, is called the precipitation in this period, and the unit is expressed in millimeters (mm).

PS。 The unit of precipitation is the length unit, and the daily precipitation should be 0.2mm, preferably 0.1mm; ; The total precipitation in a week or a month should be at least accurate to1mm. The measurement of daily precipitation should be fixed at a certain time period, such as 8: 00 am to 2: 00 pm/kloc-0.