What is Flux meaning or define Flux Unit in CMIP5 or CMIP6?

Simply, when we want to describe "flux meaning", we say a continuous moving on or passing by or as of a stream. If we define flux meaning precisely, we can say that it has a particular mean in different sciences. For example, for transportation and transport events, it is a vector quantity that we can assign a direction and magnitude to it, such as heat transfer (heat flux, the rate of heat flow across a unit area) or mass transfer. In physic and electromagnetism sciences, it is the integral over a surface flux, or the total electric or magnetic field passing through a surface.

However, in hydrology and meteorology sciences, Flux is liquid flowing or moving, or a continuous moving, like the Flux of water under a sheet of melting ice, or discharge or flow of a river or flood.

As we mentioned, flux meaning depends on the condition or subject that we use. For example, if we define Flux as a unit for precipitation, such as "CMIP5 data", it will refer to a flux of that data or variable. Flux is expressed as the rate of flow of a property per unit area, which has the dimensions [quantity].[time]-1.[area]-1. For better understanding, pay attention to the "precipitation_flux" or "precipitation" data of CMIP5 or CMIP6. Do you know the unit of precipitation in CMIP5 or CMIP6 variables?

It is better to know that define Flux in this subject, and the Flux of precipitation refers to the capacity of rainfall at the surface, as its unit is kg.m(-2).s(-1). On the other hand, Flux or water flux is typically represented as volume per area per unit of time. If you want to use this variable, you should first convert it to the acceptable dimension, such as mm or cm.

Since in Agrimetsoft we produce and use the outputs of CMIP6 and CMIP5, it would be better to elaborate the concept of "flux meaning", we present several variables with this concept in both subjects, as follows:

• Mean precipitation flux: Amount of water per unit area and time (unit: kg m-2 s-1).
• Surface latent heat flux: Flux per unit area of heat between the surface and the air because of evaporation including sublimation. Positive when directed upward and negative when directed downward (unit: W m-2).
• Surface sensible heat flux: Flux per unit area of heat between the surface and the air by motion of air only. Positive when directed upward (negative downward), (unit: W m-2).
• Surface solar radiation downwards: Radiative shortwave flux of energy downward at the surface(unit: W m-2).