Method and device for soil moisture retrieval using multi-channel collaborative algorithm and passive microwave radiometry

A method for soil moisture retrieval using multi-channel collaboration algorithm and passive microwave radiometry, being characterized in that, the method comprises the following steps:

• establishing a mathematical relationship formula between brightness temperatures at any two channels according to a microwave radiative transfer equation;
• collecting an actual brightness temperature of a core channel and an actual brightness temperature of collaborative channels;
• selecting parameters to be retrieved, wherein the parameters comprises at least a soil moisture value;
• giving a series of estimated values of parameters to be retrieved, calculating a series of predicted brightness temperatures of the collaborative channels according to the actual brightness temperature of the core channel, the microwave radiative transfer equation and the mathematical relationship formula, comparing the predicted brightness temperatures of the collaborative channels with the actual brightness temperature, and determining the soil moisture value among the series of estimated values of parameters to be retrieved according to a comparison result;
• or giving initial values of parameters to be retrieved, performing iterative calculation to obtain a series of predicted brightness temperatures of the collaborative channels according to the actual brightness temperature of the core channel, the microwave radiative transfer equation and the mathematical relationship formula, comparing the predicted brightness temperatures of the collaborative channels with the actual brightness temperature, and determining the soil moisture value according to the comparison result;
• the microwave radiative transfer equation is represented by a two-component model under the zero-order approximation;
• the mathematical relationship formula is written as:
• Tb
• ch
• ⁡
• (
• 2
• )
• total
• =
• V
• ch
• ⁡
• (
• 2
• )
• e
• -
• S
• r
• ⁢
• V
• r
• ·
• V
• ch
• ⁡
• (
• 1
• )
• e
• +
• S
• r
• ⁢
• V
• r
• ·
• Tb
• ch
• ⁡
• (
• 1
• )
• total
• S
• r
• =
• e
• ch
• ⁡
• (
• 2
• )
• s
• e
• ch
• ⁡
• (
• 1
• )
• s
• V
• r
• =
• V
• ch
• ⁡
• (
• 2
• )
• t
• V
• ch
• ⁡
• (
• 1
• )
• t
• wherein, Tbch(2)total and Tb ch(1)total are brightness temperatures at any two channels, ech(2)s and ech(1)s are microwave emissivity of the rough soil surface at the any two channels, and Vch(2)t and Vch(1)t are vegetation emissions at the any two channels, and Vch(2)e and Vch(1)e are vegetation emission term of the any two channels.