3 : 417 NRA ERA [326 ] ( ) 8 ( hpa) [4 6 ] NRA 8 ( hpa) [ (CSEs) ] ECMWF NCEP/ NCAR : ERA NRA 9W = P - R - E

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1 65 3 Vol. 65 No ACTA METEOROLO GICA SIN ICA J une 2007 Ξ LASG ECMWF NCEP/ NCAR NCEP/ NCAR ; ECMWF NCEP/ NCAR ECMWF ECMWF : 1 ( GEWEX) (WCRP) ( ECMWF) ( ERA) / ( NCEP/ NCAR) (NRA) ( WEBS) GEWEX (CSEs) ; ERA NRA [122 ; ] Ξ : ; : : (CCSF200729) ; ( ) ; (2004CB418307) : E2mail : gov. cn

2 3 : 417 NRA ERA [326 ] ( ) 8 ( hpa) [4 6 ] NRA 8 ( hpa) [ (CSEs) ] ECMWF NCEP/ NCAR : ERA NRA 9W = P - R - E (1) 9t 9Q = E + C - P (2) [15219 ] 9t Q E P C W 1999 [9 ] [ ] R NRA ( Q) ( Q v ) ( C) : Q = 1 g p s qd p (3) p ERA NRA t Q v = 1 g p s qvd p (4) p t m 3 C = - g ( Q v ) (5) km 2 19 p s p t ( 300 hpa) q v (4) (4) (5) : ERA NRA C = C m + C i (6) C C m C i 2 NRA ERA ( 1) ( hpa) (1) 730 3

3 W 9t [8 ] (1) 3 [20 ] 3. 1 E o = P o - R o (7) o 2a (2) (5. 24 mm/ d) 12 (0. 67 mm/ d) % Q 9t (1) (2) (6) mm/ d( 1) (5. 13 mm/ d) R = C = C m + C i (8) % (8) (0. 84 mm/ d) (3. 26 mm/ d) (2. 59 mm/ d) ERA NRA ERA 7 6 ERA 5 7 P = 1 A i P i A i (9) 1 A A i 2 1 (5 10 ) (11 4 ) ( 2c) ( 1 ( ) ( ) Fig. 1 The Yangtze River basin outline (thick curve) and the location of the Datong gauge station (solid circle) measuring the discharge of the river NRA ) (30. 3 %) (17. 8 %) ( ) ERA NRA ( 1 2b) ( 2c) ERA NRA 7 ERA NRA ( ) ( 2d 1) NRA

4 3 : ERA NRA (a. ;b. ;c. ;d. ( ) ERA NRA r EO r NO ( ) ) Fig. 2 OBS ERA and NRA precipitations for the Yangtze River basin during (a. Annual cycle of average monthly rainfall (mm/ d) ; b. interannual variations of annual precipitation anomaly (mm/ d) ; c. standard deviations of monthly precipitation(mm/ d) ; d. linear trend coefficients (bar) and contemporaneous correlations ( r EO r NO ) of time series of monthly precipitation of ERA and NRA with OBS with the linear trends removed the horizontal dash lines indicate the 95 % confidence level acoording to Student s t test)

5 ; ERA NRA [21 ] [ ] ERA NRA a % ( : ) ( 2d) 26 a (5 ) (1 4 ) mm/ d % ERA NRA ERA 1 ERA NRA a ;NRA ERA ERA b NRA 1 6 ERA NRA ERA (2. 47 mm/ d) 1 (0. 5 mm/ d) EAR NRA NRA ERA ( 3b c) ( %) ( %) ERA NRA ( 3d r EO r NO ) ERA 5 11 NRA ( 1 3b c) ERA ( ) % NRA 8 9

6 3 : 421 (0. 74) ERA ERA (0. 54) 3b NRA NRA NRA NRA ( d r EO r NO 2d 3 ) Fig. 3 As in Fig. 2 except for runoff ( The definition of correlations r EO and r NO in (d) is different from that in Fig. 2d see the 3rd section of text for details) d a 5 ERA NRA NRA ERA NRA ERA NRA NRA NRA mm/ d (2. 96 mm/ d) % (1. 42 mm/ d) a 3. 3 (7) ERA NRA mm/ d NRA

7 ERA (0. 44) NRA ERA NRA ERA NRA Fig. 4 Interannual variations of the annual mean evaporation anomaly (mm/ d) for the Yangtze River basin 4. 1 during in the OBS ERA and NRA data 5a ( 2a) a NRA 6 (6. 14 mm/ d) (0. 64 mm/ d) OBS ERA NRA ( (a) (b) (c) (d) (e) (f) ) Fig. 5 OBS ERA and NRA precipitations over the Yangtze River basin for (a. Seasonal cycle ; b - f. Interannual variations of annual spring (MAM) summer (JJA) fall (SON) and winter (DJ F) precipitation anomalies)

8 3 : % 1958 C m (8) mm/ d (2. 96 mm/ d) 6a C m 11 a ERA NRA C m ERA NRA mm/ d ERA NRA (1. 42 mm/ d) b - f NRA ERA ERA (8) NRA ( 7) ; ( OBS ERA NRA Fig. 6 As in Fig. 5 except for water vapor convergence transported by mean circulation

9 NRA mm 6 5 (mm/ d) Fig. 7 Annual cycle(mm/ d) of water vapor convergence over the Yangtze River basin for in the NRA data ) ERA NRA C m ERA ERA mm NRA mm C m 6 (9. 00 mm/ d) 12 (1. 70 mm/ d) % 1 6 C m mm/ d mm/ d 10 NRA ERA NRA ERA NRA ERA 12 NAR mm/ d ERA mm/ d NRA ERA mm mm mm mm % 2 (3 5 ) mm mm mm mm 8b - f b - f mm/ d NRA ERA 26 ( 5 ) ERA

10 3 : OBS ERA NRA Fig. 8 As in Fig. 5 except for precipitable water a mm/ d mm ERA ERA NRA ERA ECMWF NCEP/ NCAR NRA ; ERA NRA ERA 2 NRA 6 [ 1 ] Kalnay E Kanamitsu M Kistler R et al. The NCEP/ NCAR 402year reanalysis project. Bull Amer Meteor Soc : NRA ERA [2 ] Kgallberg P Simmons A Uppala S et al. The ERA240 Archive

11 September 2004 http : www. ecmwf. int/ publications/ library/ ecpublications/ Ο pdf/ era40/ ERA40 Ο PRS17. pdf[2004 ] [ 3 ] Roads J Kanamitsu M J uang H. Vertical structure of humidity and temperature budget residuals over the Mississippi River basin. J Geophys Res : [ 4 ] Kanamitsu M Saha S. Systematic tendency error in budget cal2 culations. Mon Wea Rev : [ 5 ] Schubert S D Rood R B Pfaendtner J. An assimilated dataset for earth science applications. Bull Amer Meteor Soc : [ 6 ] Roads J Chen S Kanamitsu M et al. Surface water character2 istics in the NCEP global spectral model and reanalysis. J Geo2 phys Res (19) : [ 7 ] Roads J Kanamitsu M Stewart R. CSE water and energy bud2 gets in the NCEP2DOE reanalysis II. J Hydrometeor (3) : [ 8 ] William J Gutowski J Chen Y gtles Z. Atmospheric water va2 por transport in NCEP2NCAR reanalyses : Comparison with river discharge in the central United States. Bull Amer Meteor Soc : [ 9 ]. NCEP/ NCAR valley. Chinese Sci Bull : (2) : [ 10 ] Roads J Betts A. NCEP2NCAR and ECMWF reanalysis surface water and energy budgets for the Mississippi River basin. J Hy2 drometeor : [11 ] Maurer E O Donnell G Lettenmaier D et al. Comparison of NCEP/ NCAR reanalysis NCEP II AMIP water and energy budgets with macroscale hydrologic model simulations. J Geo2 phys Res : [ 12 ] Leung L R Qian Y Han J L et al. Intercomparison of global reanalyses and regional simulations of cold season water budgets in the Western United States. J Hydrometeor : [13 ]. GAME NCEP 1998 HUBEX (2) : [14 ] Marengo J A. Characteristics and spatio2temporal variability of the Amazon River basin water budge. Clim Dyn : [15 ] Li W P. Moisture flux and water balance over the South China Sea during late boreal spring and summer. Theor Appl Climatol : [ 16 ] (3) : [ 17 ] Wang K L Cheng G D Xiao H L et al. The westerly fluctua2 tion and water vapor transport over the Qilian2Heihe valley. Sci2 ence in China (Ser D) : [18 ] Xu X D Chen L S Wang X R et al. Moisture transport source/ sink structure of Mei Yu rain belt along the Yangtze River [19 ] (3) : [20 ] Qiu X F Zeng Y Miao Q L et al. Calculating surface annual evapotranspiration by conventional meteorological observations. Science in China (Series D) (3) : [ 21 ] (A03) :

12 3 : 427 WATER BUD GET FOR THE YANGTZE RIVER BASIN AND EVAL UATION OF ECMWF AND NCEP/ NCAR REANALYSIS DATA Zhao Ruixia Wu Guoxiong 2 1 N ational Meteorological Center China Meteorological B ureau Beijing L A S G Institute of A t mospheric Physics Chinese Academy of Sciences Beijing Graduate School of Chinese Academy of Sciences Beijing Abstract The surface and atmospheric water budgets for the Yangtze River basin were examined using the available observations ECMWF and NCEP/ NCAR reanalysis data during 1958 to 1983 and 1990 to 2000 respectively and the water budget components in this study include precipitation runoff evaporation moisture convergence and so on. Based on the observations the water budgets for the Yangtze River basin and their seasonal cycle interannual variations and linear tends were analyzed. On the average of long time the river basin area is a moisture sink. It s interesting that the water vapor is transported to the basin area by the mean air flow instead of the transient eddies which are close associated with synoptic systems and always diverges moisture out of the river basin. On the surface the evaporation is almost equal to the runoff and plays a very important role in the water cycle of t he river basin. Evident annual and interannual variabilities exist in most component s of t he at mo2 sp heric and surface water budget s and only t he interannual variations of evaporation and precipitable water are smaller. Precipitation and moisture convergence by the mean transport both peak in J une and then decrease till December. But t he maxima and minima of runoff and precipitable water occur in J uly and J anuary respectively one mont h later t han t hose of precipitation. During 1958 to 1983 precipitation slightly increased in summer half year and decreased in winter half year insignificantly and insignificant increasing t rends existed in t he annual mean evaporation and st ream flow. Furthermore the contrast analyses of ECMWF and NCEP/ NCAR reanalysis data were performed to evalu2 ate t heir performances in describing t he hydrological cycle in t he Yangtze River basin. Firstly t he NCEP/ NCAR reanalysis data overestimate precipitation runoff and evaporation while underestimate precipitable wa2 ter and moisture convergence as compared with the observations. In the ECMWF reanalysis data the precipita2 tion and runoff are basically close to the observations but the evaporation is overestimated and the precipitable water and moisture convergence are also underestimated but closer to the observations than the NCEP/ NCAR reanalysis data. Fort unately bot h reanalysis data especially t he ECMWF reanalysis data can describe t he an2 nual and interannual variations of water budgets well but the two sets of reanalysis data especially the ECMWF reanalysis data exaggerate linear trends over the period of year 1958 to So in a word the ECMWF and NCEP/ NCAR reanalysis data can be used to describe the annual and interannual variations of the water budgets for the Yangtze River basin but one must be cautious to use the reanalysis data to calculate the linear trends of water budget s. Key words : Yangtze River basin Water budget Evaluation.

Microsoft Word - 1--齐继峰_new_.doc

Microsoft Word - 1--齐继峰_new_.doc 45 6 Vol.45, No.6 2014 11 OCEANOLOGIA ET LIMNOLOGIA SINICA Nov., 2014 * 1, 2, 3 1, 2 1, 2 1, 2 (1. 266071; 2. 266071; 3. 100049) 1956 2005 PN, NCEP,, (PDO),, 19 33Sv, 24.30Sv(1Sv=10 6 m 3 /s);, 1956 2005