Precipitation Estimates Methods - Furuno WR2120 Operator's Manual

2.4.3.

Precipitation Estimates Methods

It is possible to accommodate by adjusting the following parameter if rainfall is large or small.
Zh method
1) Use standard equation,
2) Parameters "B" and "β" are able to set from advanced setting.
Default value of "B" is 200. "β" is 1.6. Zh unit is using dBZ.
Zh, Ah decay correction method
1) Calculate ��ℎ
2) Where, the parameters b1, b2 and range bin data resolution ∆r are able to set from
advanced setting. Default values are 0.233, 1.020 and 0.1 [km], respectively.
3) Calculate rainfall intensity R from ��ℎ
described.
Kdp+Zh method
1) Calculate the rainfall intensity R from "Kdp" or from "Zh". This will be selected by thresholds setting
of RainMap. In addition, calculation from Kdp can be selected to use elevation or not at "Rainfall
intensity estimation correction by EL" in the "Signal processing" under the advanced setting of
RainMap.
(With elevation correction [OFF])
(With elevation correction [ON])
Rain ( Kdp ) = c × (a + 2.64 × 10
2) Where, the parameters a, b, and c are able to set from advanced setting. Default values are 19.6,
0.825 and 1.2, respectively.
3) Where, the parameters th ( Kdp ) and th ( Zh ) are able to set from advanced setting. Default
values are 0.3 [deg/km], and 30 [dBZ], respectively.
Rain ( Zh ) = (
from Zh and Ah
��������
( i ) = Zh ( i ) + 2 × ∑ Ah ( i )
Zh
corr
Ah ( i ) = b1 × Kdp ( i )
Rain ( ��ℎ
��������
Rain ( Kdp ) = c × a × Kdp
−2
Rainfall intensity R = {
1
1 Zh
β
) × 10 10×β
B
i
i=0
b2
using same method of "Zh method" previously
��������
1
��ℎ
1
β
��������
) = (
) × 10 10×β
B
b
−3
× ���� + 1.73 × 10 × ����
Kdp > ��ℎ ( Kdp )
Rain ( Kdp )
Zh > ��ℎ ( Zh )
Rain ( Zh )
24
× ∆r
2 −4 3
+ 1.09 × 10 × ����
other
)