swedish meteorological and hydrological institute se-601 76 norrköping, sweden comparison of areal...
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Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
COMPARISON OF AREAL PRECIPITATION ESTIMATES: A CASE STUDY FOR A
CENTRAL SWEDISH CATCHMENT
Jonas Olsson, Barbro Johansson(presented by Günther Haase)
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Study region - Gimån catchment
• Catchment area: 4 300 km²• Mean annual precipitation: 700 mm• Mean altitude: 340 m.a.s.l. (range: 20-540 m.a.s.l.)
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Data sources and analyses
Sources:• PTHBV: interpolated gauge data• HIRLAM: NWP model (+30h - +6h forecasts)• RADAR: gauge-adjusted radar data• MA22, MA11: mesoscale analysis, real-time (22) and climate-
corrected(11)
Resolution, extension:• Temporal: daily accumulations during 2002• Spatial: ~22 km resolution in 72120 km2 grid (20 grid nodes)
Analyses:• Temporal: descriptive statistics and autocorrelation of daily spatial
mean precipitation• Spatial: standard deviation and correlation
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Temporal analysis - descriptive statistics
Annual total
300
400
500
600
HIRLAM MA22 MA11 PTHBV RADAR
(mm
)
Mean daily standard deviation
1,5
2
2,5
3
HIRLAM MA22 MA11 PTHBV RADAR
(mm
)
Daily maximum
0
5
10
15
20
25
HIRLAM MA22 MA11 PTHBV RADAR
(mm
)
Dry days (prec.<0.1 mm)
0
10
20
30
40
50
HIRLAM MA22 MA11 PTHBV RADAR
(%)
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Temporal analysis - seasonal & autocorrelation
0
20
40
60
80
100
120
J F M A M J J A S O N D
Pre
cip
ita
tio
n (
mm
)
HIRLAM
MA22
MA11
PTHBV
RADAR
-0,1
0
0,1
0,2
0,3
0,4
0,5
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Lag (days)
Co
rre
lati
on
co
eff
icie
nt
HIRLAM
MA22
MA11
PTHBV
RADAR
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Spatial analysis2002 totals
1440000 1460000 1480000 1500000 1520000 1540000
6940000
6960000
6980000
7000000
400m m
450m m
500m m
550m m
600m m
650m m
700m m
750m m
1440000 1460000 1480000 1500000 1520000 1540000
6940000
6960000
6980000
7000000
400m m
450m m
500m m
550m m
600m m
650m m
700m m
750m m
1440000 1460000 1480000 1500000 1520000 1540000
6940000
6960000
6980000
7000000
400m m
450m m
500m m
550m m
600m m
650m m
700m m
750m m
1440000 1460000 1480000 1500000 1520000 1540000
6940000
6960000
6980000
7000000
400m m
450m m
500m m
550m m
600m m
650m m
700m m
750m m
1440000 1460000 1480000 1500000 1520000 1540000
6940000
6960000
6980000
7000000
400m m
450m m
500m m
550m m
600m m
650m m
700m m
750m m
PTHBV
HIRLAM
RADAR (maximum=1390 mm)
MA22
MA11
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Spatial analysis - standard deviation & correlation
Standard deviation: mean daily
0,5
1
1,5
HIRLAM MA22 MA11 PTHBV RADAR
(mm
)
Standard deviation: 2002 total
0
50
100
HIRLAM MA22 MA11 PTHBV RADAR
(mm
)
206
0,4
0,5
0,6
0,7
0,8
0,9
1
25 50 75 100 125
Distance (km)
Co
rre
lati
on
co
eff
icie
nt
HIRLAM
MA22
MA11
PTHBV
RADAR
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Summary
- PTHBV vs. MA: The mesoscale analysis consistently generated the lowest amount of precipitation, possibly due to (i) no correction for observation losses and (ii) an underestimation in synoptical observations.
- HIRLAM: Somewat different seasonal cycle than the other sources. Low daily areal variability, possibly due to areal smoothing in the model. High areal variability of 2002 totals, possibly due to orographically induced small but systematic areal variations.
- RADAR: A distinct inhomogeneity was found, with precipitation amounts being consistently overestimated by ~8 mm/day over a region of 500-1000 km² during October-December. Possible cause: temporary improper functionality of the Östersund radar, north-west of the study catchment.
Swedish Meteorological and Hydrological InstituteSE-601 76 Norrköping, SWEDEN
Runoff simulation (HBV model) 2000-2002Input: PTHBV
0
200
400
600
00-01-01 00-07-01 01-01-01 01-07-01 02-01-01 02-07-01
Dis
char
ge
(mm
)
HBV OBSERVED
Input: RADAR
0
200
400
600
00-01-01 00-07-01 01-01-01 01-07-01 02-01-01 02-07-01
Dis
char
ge
(mm
)
HBV OBSERVED
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