This study investigates the error characteristics of six quasi-global satellite precipitation products and associated error propagation in flow simulations for 16 mountainous basin scales (areas ranging from 255 to 6967 km2) and two different periods (May-Aug & Sep-Nov) in northeast Italy. The satellite products used in this study are 3B42-CCA, 3B42-V7, CMORPH and PERSIANN with their respect gauge-adjusted products. To evaluate the error propagation in flood simulations satellite precipitation datasets were used to force a gauge-calibrated hydrologic model to simulate runoff for the 16 basins, and comparing them to the gauge-driven simulated hydrographs for a range of moderate to high flood events spanning a nine-year period (2002 to 2009). Statistics describing the systematic and random error, the temporal similarity and error ratios between precipitation and runoff are presented.

1. Classification
• Basin scale: 9 medium and 7 large (less and greater than 1000 km2);
• Seasonality: warm and cold period (May-Aug and Sep-Nov);
• Severity: low to moderate and high flow rate (below and above the 90th percentile
of gauge-simulated runoff).
Evaluating Satellite Precipitation Error Propagation in Runoff Simulations of Mountainous Basins
Yiwen Mei1, Efthymios I. Nikolopoulos2, Emmanouil N. Anagnostou1 and Marco Borga2
1 Civil and Environmental Engineering, University of Connecticut, Storrs, CT, USA
2 Department of Land, Environment, Agriculture and Forestry, University of Padova, Legnaro, Padova, Italy
This study investigates the error characteristics of six quasi-global satellite
precipitation products and associated error propagation in flow simulations for 16
mountainous basin scales (areas ranging from 255 to 6967 km2) and two different
periods (May-Aug & Sep-Nov) in northeast Italy. The satellite products used in this
study are 3B42-CCA, 3B42-V7, CMORPH and PERSIANN with their respect
gauge-adjusted products. To evaluate the error propagation in flood simulations
satellite precipitation datasets were used to force a gauge-calibrated hydrologic
model to simulate runoff for the 16 basins, and comparing them to the gauge-driven
simulated hydrographs for a range of moderate to high flood events spanning a nine-
year period (2002 to 2009). Statistics describing the systematic and random error, the
temporal similarity and error ratios between precipitation and runoff are presented.
• Upper Adige River Basin (6967 km2);
• 104 rain gauges and 143 temperature stations;
• Integrated Catchment Hydrological Model (ICHYMOD):
snow routine, soil moisture routine, flow routine
Introduction
Study Area
Methods
Error metrics
• Mean Relative Error (MRE);
• Centered Root Mean Square Error (CRMSE);
• Correlation Coefficient (CC);
• Ratio between Error Metric (γ).
Role of elevation on systematic error
Effects of basin scale, seasonality and flow severity
Error Propagation
May-AugSep-Nov
3B42 CMORPH PERSIANN 3B42 CMORPH PERSIANN
Mean Basin Elevation (m a.s.l.)
MREinFlow
MREinRainfall
MRE
Above90th
Percentile
Below90th
Percentile
CRMSE CC
γMRE γCRMSE γCC
Satellite Precipitation Products
Satellite Precipitation Products
Conclusions
• Systematic error ranged from underestimation to
overestimation with the mean basin elevation;
• Low to moderate flow rate group (below the 90th
percentile threshold) yield higher consistency
compared to the high flow rate one;
• Random errors are reducing and converging with
basin scale and from cold to warm period;
• Gauge-adjusted products outperform their near-real-
time counterparts;
• Lower degree of variability from ratios of random
error and temporal similarity metrics for larger basins
and warm period cases;
• Significant dampening effect in random error
compared to the other metrics.