Hydrological modelling of the Zambezi catchment for ... - TU Delft
Hydrological modelling of the Zambezi catchment for ... - TU Delft
Hydrological modelling of the Zambezi catchment for ... - TU Delft
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HYDROLOGICAL MODEL INPUT DATA<br />
Table 3.1: Validation statistics <strong>of</strong> rainfall estimates from MIRA and GPI compared with o<strong>the</strong>r rainfall<br />
estimation methods (Todd et al., 2001)<br />
Independent validation data MIRA GPI<br />
CC Ratio RMSE CC Ratio RMSE<br />
SSM/I BUC [1]<br />
0.47 1.1 2.2 0.04 1.54 2.84<br />
SSM/I BUC [2]<br />
EPSAT gauge data [3]<br />
GPCP gauge data [4]<br />
WetNet PIP-3 GPCP land based<br />
gauges [5]<br />
WetNet PIP-3 Comprehensive Pacific<br />
Rainfall Data Base [6]<br />
0.54 1.01 2.02 0.24 1.97 1.98<br />
0.96 1.08 2.04 0.76 1.4 5.3<br />
0.54 1.76 25.17 0.66 2.74 36.9<br />
0.8 1.24 82.6 0.69 1.69 147.5<br />
0.85 0.96 74.6 0.75 1.08 100.8<br />
[1] 140°-180°E, 20°S-20°N, July 1991, 0.25°, conditional instantaneous, n= 515, mean=1.7mmhr -1<br />
[2] 140°-180°E, 20°S-20°N, July 1991, 0.5°, conditional instantaneous, n= 228, mean=1.04 mmhr -1<br />
[3] 2°-3°E, 13°-14°N, July 1992, 1°, daily, n=30, mean=3.5mm.day -1<br />
[4] Selected locations (see Todd et al., 2001; Table 2), July 1991,2.5°, pentad, n= 46, mean=8.7mm.pentad -1<br />
[5] Selected locations (see Morrissey et al., 1994), 2.5°, monthly, n=159, mean =83.7mm<br />
[6] Selected locations (see Morrissey et al., 1994), 2.5°/monthly, n=17, mean=217.6mm<br />
Rain rate [mm/h]<br />
40<br />
30<br />
20<br />
10<br />
0<br />
1<br />
Validation Validatation <strong>of</strong> <strong>of</strong> MIRA and GPI<br />
4<br />
7<br />
10<br />
13<br />
16<br />
19<br />
22<br />
25<br />
Time [days]<br />
Gauge MIRA GPI<br />
28<br />
Figure 3.3: MIRA and GPI compared to rain gauges (Todd et al., 2001).<br />
3.1.1.1 Data<br />
The MIRA algorithm has calculated daily rainfall estimates in mean mm/hour <strong>for</strong> <strong>the</strong> period<br />
from 1993 till 2002. It covers only <strong>the</strong> African continent and has a spatial resolution <strong>of</strong> 0.1° x<br />
0.1°. The rainfall estimates from MIRA can be downloaded from <strong>the</strong> Sou<strong>the</strong>rn African<br />
Regional Science Infinitive (SAFARI 2000)-site:<br />
http://ltpwww.gsfc.nasa.gov/s2k/html_pages/groups/precip/daily_rainfall_mira. html<br />
Although <strong>the</strong> high temporal resolution <strong>of</strong> <strong>the</strong> rainfall estimates, <strong>the</strong>re are un<strong>for</strong>tunately some<br />
gaps (Table 3.2). These gaps are <strong>for</strong> example due to <strong>the</strong> fact that some data files became<br />
corrupt by archiving on CD. To repair <strong>the</strong> data one <strong>of</strong> <strong>the</strong> following actions is executed:<br />
24