Extended Abstract

Fig. 4 The same as Fig.3, but at Wangjiaba.The Nash-sutcliff efficiency coefficient was also obtained to assess the si mulated discharge of threeEPS at Xixian and Wangjiaba station. The Nash-sutcliff efficiency coefficient was written as:Where Q0and2( Q0 Qs)E 1.0 2( Q Q )00Qsare observed a nd si mulated discharge, and Q0is th e tim e av erage of ob serveddischarge. A value of E close to 1.0 indicates the good agreement of observation and the prediction(Nash and Sutcliffe 1970). It is obviously seen from table 2 that the best E appeared with that drivenby ECM WF which is 0.97 and 0.96 while t he worst E appeared with NCEP. For Wang jiaba, theaverage of E with ECMWF is 0.68, which is much better than the other two EPS. The maximum,minimum a nd a verage E were als o given in t able 2. Something must b e poi nted o ut is t hat otherreferences should also be taken into consideration when you must make decision with these results tomake sure not be confused.Table 2 Nash-Sutcliffe efficiency coefficient of Wangjiaba and XixianWangjiabaXixianMax Min Ave Max Min AveEC 0 .97 0.54 0.68 0.96 -0.15 0.26NCEP -1 .22 -1.47 -1.36 0.41 -0.08 0.21CMA 0 .74 0.28 0.51 0.76 -0.45 -0.13(1 )5. Conclusion and DiscussionsDriving by the TIGGE pro vided EC MWF, NCEP and CMA EPS ou tput to tal precipitation andtemperature, disc harges at Xixia n an d Wa ngjiaba control stations were simulated and comp ared toobservation. It s eems t hat the result s are n ot in good consist ence with th e analysis of p recipitation(Zhao et al 2010). The performance of all three EPS at Xixian is not so satisfied, especially on the firstonset of rising limb, while the tendency of the recession limb was well performed, but is much lowerthan the observation. At Wangjiaba, the performance is better than at Xixian station. All captured the-169-