Geology Reference
In-Depth Information
Fig. 5.1 The river Brue catchment, Southwest England, the United Kingdom
of 1.92 m
3
/s, for the period from 1961 to 1990. The catchment has a dense rain
gauge network which comprises of 49 Cassella 0.2 mm tipping-bucket rain-gauges,
having a recording time resolution of 10 s. This high dense rain-gauge network
provides at least one rain-gauge in each of the 2 km grid squares within the
catchment.
5.1.2 Data from the Hydrological Radar Experiment
(HYREX) Project
The HYdrological Radar EXperiment (HYREX) was a Natural Environment
Research Council (NERC) Special Topic Research Programme which ran from
1993 for three years. Later, data collection was extended to April 2000. The main
aim of this highly funded research was to understand the rainfall variability as
sensed by weather radars and to compare the reliability with land based rain gauge
network. The large volume of data generated from this research attracted many good
quality research activities which dealt with the evaluation rainfall variability and its
impact on the river
flood forecasting at the catchment scale [
10
,
17
,
18
].
HYREX members chose the River Brue catchment due to the presence of well
equipped gauging and weather stations and the radar coverage, given by the weather
radars from Wardon Hill (C-band radar which is 30 km south of the catchment),
Cobbacombe Cross (C-band radar which is 70 km west of the catchment)
and Chilbolton radar installations. The radars complete one azimuthal scan every
minute, and cycle through a 4
ow and
°
scan elevations in every 5 min (0.5, 1.0, 1.5 and
2.0
ectivity information given by the weather radars was converted into
rainfall information covering two Cartesian Grids: an 82
°
). The re
82 grid of 5 km
2
pixels
×
76 grid of 2 km
2
pixels
covering an area with diameter of 76 km. The River Brue catchment lies in the 2 km
grid for all three radar ranges at the study location. Because of that, only the
covering an area with diameter of 210 km and a 76
×
