GB/T 44956-2024Weather forecast verification—Precipitation and air temperature forecast (English PDF)

3.1 precipitation

During a certain period of time, liquid (rain) or solid (snow) precipitation (after melting) that falls from the sky to the ground without evaporation, infiltration, or flow.

The depth at which the water is lost and accumulates on the horizontal plane.

Note. The unit is millimeter (mm).

[Source. GB/T 28592-2012, 2.1]

3.2 Temperature

During ground meteorological observations, the air temperature at a height of 1.50m above the ground is measured inside radiation protection devices such as louvered boxes.

Note. The unit is Celsius (°C).

[Source. GB/T 35226-2017, 3.1, modified]

3.3 forecast verification

According to the forecast results and actual observations, the forecast quality is tested according to certain methods.

[Source. GB/T 38308-2019, 2.6]

3.4 forecastskil

A comparison of the forecast accuracy of one forecasting method relative to another.

Note 1.Used to compare the relative quality of two forecast methods.

Note 2.The actual forecast accuracy is usually compared with the forecast accuracy of the climate persistence forecast method. If the former is higher than the latter, it is called "positive skill".

The former is equal to or lower than the latter and is called "zero skill" or "negative skill".

4.1 Precipitation forecast verification

Precipitation forecast verification is a test for precipitation forecast, including graded precipitation verification, cumulative precipitation verification and sunny/rainy (snowy) verification.