Technique for estimating rainfall from a meteorological radar with polarization diversity

A process for estimating a precipitation rate by means of a bipolar radar, comprising:

• differential phase Φdp and attenuated reflectivity Z according to at least one of polarizations H or V are measured by means of said bipolar radar, over a given interval [r1, r0] of path radius r with respect to said radar, wherein a reflectivity profile Z(r) is determined,
• an estimate of the attenuation value at r0K(r0) is determined from the attenuated reflectivity profile thus measured, as well as from a difference in differential phase between r0 and r1;
• an estimate of the specific attenuation at r K(r) as a function of the attenuation K(r0) thus determined and of the attenuated reflectivity profile Z(r) is determined, wherein the estimate K(r) of the specific attenuation is determined as a function of r from the equation Z b ⁢ ( r ) K ⁢ ( r ) - Z b ⁢ ( r 0 ) K ⁢ ( r 0 ) = I ⁢ ( r , r 0 )
• and wherein the estimate of the value K(r0) of the attenuation R0 is determined from the equation K ⁢ ( r 0 ) ⁢ ∫ r 1 r 0 ⁢ Z b ⁢ ( s ) Z b ⁢ ( r 0 ) + K ⁢ ( r 0 ) · I ⁢ ( s , r 0 ) ⁢ ⅆ s = γ · ( φ dp ⁢ ( r 0 ) - φ dp ⁢ ( r 1 ) )
• where:
• l(s,r0)=0.46b∫rr0Zb(u)du,
• b being the exponent of the power relation
• K(r)=a[Z0(r)]b (Z0:unattenuated reflectivity)
• and where γ is the parameter of proportionality between the specific attenuation and the differential rate of variation of the phase;
• the rate of precipitation R(r) is determined knowing K(r).