paprika’s hydrological stations
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Paprika’s hydrological stations
Basin Area (km²) % glac.
Phakding 1208 28.5
Pheriche 146 38.8
Dingboche 136 37.9
Khote 148 35,3
More Paprika’s hydrology
Pangboche4000-6500m
Kharikola1600-4000m
Two smallslope basinscould bestudied in adetailedhydrologicalfield approach.
PhD project submitted for funding (feb. 2011) atUM2 CoP
Spatialized climate data sets
Available climate datasets
précipitation
Type Name Spatialresol.
Time resol.
Period Derived products Format
Precip. Aphrodite 10.3 0.25° daily 1951-2006 monthlyseasonalyearly
netcdfmatlab
Precip. CRUTS 3.0 0.5° monthly 1901-2006 seasonal, yearly netcdf
Precip. TRMM 3B42 0.25° daily 1998-2008 daily matlab
Air temp.
CRUTS 3.0 0.5° monthly 1901-2006 seasonal, yearly netcdf
Air temp.
Ncep/Ncar reanalysis17 levels
2.5° daily 1948-2009 regrided on 0.25° (*)daily, monthly, seasonal, yearly
netcdf
Air temp.
Ncep/Ncar reanalysis2m (gauss grid)
1.8° daily 1948-2009 regrided on 0.25° (*)daily, monthly, seasonal, yearly
netcdf
(*) bilinear interpolation
Comparison of seasonal (monthly) precipitation
CRU versus Aphrodite on 1952-2006 period over Koshi basin
Spatial comparison of monthly precipitation
CRU versus Aphrodite on 1952-2006 period over Koshi basin (resol = 0.25°)
monthly bias (CRU-Aphro) monthly correlation between CRU and Aphro(636 values for each cell)
Bias: higher CRU values over Tibet plateau (~1000 mm/year)better agreement in the southern basin
Correlation:good correlation CRU-Aphrodite on southern part of the basin
Spatial comparison of monthly precipitation
TRMM versus Aphrodite on 2000-2007 period over Koshi basin (resol = 0.25°)
monthly bias (Aphro-TRMM) monthly correlation between TRMM and Aphro(120 values for each cell)
Bias: higher TRMM values over Tibet plateau and in south of Nepal (up to 350 mm/year)
probably reflect a bad aphrodite precipitation interpolation (lack of gages) over Tibet plateau higher Aphrodite values along the montains (up to 1000 mm/year)
TRMM :only rain , Aprhodite : rain+ snowbetter agreement over a small area in the southern basin
Correlation:low correlation TRMM-Aphrodite on north-west part of the basin
Monthly precipitation correlation Aphro, TRMM
84.5 85 85.5 86 86.5 87 87.5 88 88.5
26.5
27
27.5
28
28.5
29
29.5
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Monthly precipitation : mean bias Aphro-TRMM (mm)
84.5 85 85.5 86 86.5 87 87.5 88 88.5
26.5
27
27.5
28
28.5
29
29.5
-60
-40
-20
0
20
40
60
80
100
120
DHM’s hydrological balance
Awa Gaon
Mulghat Simle
Khurkot Rabuwabazar
Comparison of annual/monthly discharge and precipitation - 5 sub catchments of Koshi river at Chatara (93% of Koshi catchment area at Chatara) -
600.1 : Awa Gaon 29 700 km²606 : Simle 33 500 km²690 : Mulghat 5 880 km²652 : Khurkot 10 200 km²670 : Rabuwabazar 3 720 km²695 : Chatara 57 300 km²
Aims : Analysing the reliability of discharge measurements Basic anlayses of the catchment hydrology
Data :-Discharge : DHM data base-Precipitation : spatial mean precipitation calculated for each catchment with aphrodite data
Chatara
Basin Area (km²)
% glac.
Chatara 57800 2,4
Simle 33500 5,9
Awa Goan 29700 6,5
Rabuwabazar 3720 13,9
Muhlghat 5880 9,1
Khurkot 10200 8,8
Simle-AwaG 3800 0,9
The main problems :
1. For all the catchment the runoff coefficients C (annual and seasonal time steps) happen to be higher than one
0.000
0.500
1.000
1.500
2.000
2.500
600.000
1100.000
1600.000
2100.000
2600.000
1950 1960 1970 1980 1990 2000
co
eff
icie
nt d
'ec
ou
lem
en
t
Lam
e d
'eau
(m
m)
Date (année)
comparaison pluie débitBV 670 Dud Koshi
Debit annuel (mm)
pluie annuelle (mm)
coefficient d'écoulement
Exemple of the Dud Koshi catchment at the annual scale :
All catchmentsAll seasonsC >>1 in 2005
2. This pattern can not be explain by snow or ice melting as it is • observed in all season an mainly in Winter and October-November• it does not exhibit a seasonal cycle
bv 670 Dud Koshi Hiver
0
20
40
60
80
100
120
140
160
1965 1970 1975 1980 1985 1990 1995 2000 2005
Date (année)
lam
e d
'eau
(m
m)
0.000
5.000
10.000
15.000
20.000
25.000
30.000
co
eff
icie
nt
d'e
co
ule
men
t
debit
pluie
coefficientd'ecoulement
Exemple of Dud Koshi winter (=DJF) runoff coefficient
May be it can be explain • by the uncertainty of low flows measurement ?• by the catchment precipitation estimations (Aphrodite)
3. Inconsistency for Arun river :• Decreasing discharges at Awa Gaon and Simle• No decreasing trend observed for the precipitation
comparaison pluie débit BV 606 Arun
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
800.00
1986 1991 1996 2001 2006
date (année)
lam
e d'
eau
(mm
/an)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8co
effic
ient
d'e
coul
emen
t
debit annuel
pluie annuelle
coefficientd'écoulement
comparaison pluie et débit annuel BV600.1 Plateau tibétain
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
1985 1990 1995 2000 2005
date (année)
lam
e d
'eau
(m
m/a
n)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
coef
fici
ent
d'e
cou
lem
ent
debit annuel
pluie annuelle
coefficientd'écoulement
Arun – Awa Gaon – 29700 km²
Arun – Simle – 33500 km²
Decreasing trend in annual discharge
Break in the annual discharge time serie(near 1996-1997)
No significant trend for annual precipitation
(green curves)
4. Inconsistency in the sub catchments contributions to the total Koshi catchment discharge•We have computed the ratio Qsubcatchment/Qkoshi (annual and seasonal scale) The sum of the 5 ratio is greater than one !
Annual contribution of the 5 subcatchments to the Koshi annual discharge (black curve)
This pattern also appears at the seasonal scale not systematicaly the same year than for annual discharges the years with runoff coefficient and contribution inconsistencies are not simultaneous !
Comparison of monthly temperature, discharge and precipitation (standardized values)
Show consistent pattern : maximum discharge, temperature and precipitation simultanously happen during summer (Monsoon)
Data bases
HYDRACCESS•DHM hydro & climato•EvK2 climato•Paprika hydro &climato
Contact :Pierre Chevallier
Spatial infos•Aphrodite•CRU•TRMM•NCEP•Etc.
Contacts:François DelclauxLuc Neppel
ArcGis
Projection WGS 84UTM 45N (Nepal)UTM 43N (Pakistan)
DEMSnow CoverHydrologyEtc.
Contacts:Pierre Chevallier
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