Paprika’s hydrological stations
BasinArea (km²)% glac. Phakding Pheriche Dingboche Khote 14835,3
More Paprika’s hydrology
Pangboche m Kharikola m Two small slope basins could be studied in a detailed hydrological field approach. PhD project submitted for funding (feb. 2011) at UM2 CoP
Spatialized climate data sets
Available climate datasets précipitation TypeNameSpatial resol. Time resol. PeriodDerived productsFormat Precip.Aphrodite °daily monthly seasonal yearly netcdf matlab Precip.CRUTS °monthly seasonal, yearlynetcdf Precip.TRMM 3B420.25°daily dailymatlab Air temp. CRUTS °monthly seasonal, yearlynetcdf Air temp. Ncep/Ncar reanalysis 17 levels 2.5°daily regrided on 0.25° (*) daily, monthly, seasonal, yearly netcdf Air temp. Ncep/Ncar reanalysis 2m (gauss grid) 1.8°daily regrided on 0.25° (*) daily, monthly, seasonal, yearly netcdf (*) bilinear interpolation
Comparison of seasonal (monthly) precipitation CRU versus Aphrodite on period over Koshi basin
Spatial comparison of monthly precipitation CRU versus Aphrodite on 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 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+ snow better agreement over a small area in the southern basin Correlation: low correlation TRMM-Aphrodite on north-west part of the basin
DHM’s hydrological balance
Awa Gaon Mulghat Simle Khurkot Rabuwa bazar Comparison of annual/monthly discharge and precipitation - 5 sub catchments of Koshi river at Chatara (93% of Koshi catchment area at Chatara) : Awa Gaon km² 606 : Simle km² 690 : Mulghat km² 652 : Khurkot km² 670 : Rabuwabazar km² 695 : Chatara 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
BasinArea (km²) % glac. Chatara ,4 Simle ,9 Awa Goan ,5 Rabuwabazar ,9 Muhlghat 58809,1 Khurkot ,8 Simle-AwaG 38000,9
The main problems : 1. For all the catchment the runoff coefficients C (annual and seasonal time steps) happen to be higher than one Exemple of the Dud Koshi catchment at the annual scale : All catchments All seasons C >>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 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 Arun – Awa Gaon – km² Arun – Simle – km² Decreasing trend in annual discharge Break in the annual discharge time serie (near ) 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 Delclaux Luc Neppel
ArcGis Projection WGS 84 UTM 45N (Nepal) UTM 43N (Pakistan) DEM Snow Cover Hydrology Etc. Contacts: Pierre Chevallier