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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

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