Articles | Volume 6, issue 3
Nat. Hazards Earth Syst. Sci., 6, 377–386, 2006
https://doi.org/10.5194/nhess-6-377-2006

Special issue: Advances in radar, multi-sensor and hydrological modelling...

Nat. Hazards Earth Syst. Sci., 6, 377–386, 2006
https://doi.org/10.5194/nhess-6-377-2006

  17 May 2006

17 May 2006

On the use of radar reflectivity for estimation of the areal reduction factor

F. Lombardo, F. Napolitano, and F. Russo F. Lombardo et al.
  • Department of Hydraulics, Highways and Roads, University of Rome “La Sapienza", 00184 Rome, Italy

Abstract. In order to estimate the rainfall fields over an entire basin raingauge, pointwise measurements need to be interpolated and the small-scale variability of rainfall fields can lead to biases in the rain rate estimation over an entire basin, above all for small or medium size mountainous and urban catchments.

For these reasons, several raingauges should be installed in different places in order to determine the spatial rainfall distribution during the evolution of the natural phenomena over the selected area.

In technical applications, many empirical relations are used in order to deduce heavy areal rainfall, when just one raingauge is available.

In this work, we studied the areal reduction factor (ARF) using radar reflectivity maps collected with the Polar 55C, a C-band Doppler dual polarized coherent weather radar with polarization agility and with a 0.9° beamwidth.

The radar rainfall estimates, for an area of 1 km2, were integrated for heavy rainfall with an upscaling process, until we had rainfall estimate for an area of 900 km2.

The results obtained for a significant amount of data by using this technique are compared with the most important relations of the areal reduction factor reported in the literature.

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