A new method for establishing hydrologic fidelity of snow depth measurements based on snowmelt–runoff hydrographs

Figures & data

Table 1. Four-category skill score matrices used in this study.

Method	(a) Gerrity skill score	(b) LEPS skill score	(c) Barnston skill score
Matrix of parameters

Figure 1. Pecatonica watershed map (adopted from Park and Markus 2014).

Figure 2. Volumetric percentage of snow and rain contributing to each flood event at Freeport on the Pecatonica River (USGS no. 05435500).

Figure 3. Observed snow depths (colors) at the beginning of each flood event at five climate gages and the corresponding flood peaks (wide boxes with black borders) at Freeport on the Pecatonica River for 17 selected snowmelt-driven floods.

Figure 4. Example of VIC model simulation for a flood in 1975.

Table 2. Range of model parameters used in calibration (modified from Park and Markus 2014).

Soil parameter	Description	Unit	Range	Calibration value
Bi	Infiltration shape parameter	-	0−0.4	0.04
Ds	Fraction of Dsmax where nonlinear baseflow begins	-	0−1	0.1
Dsmax	Maximum subsurface flow rate	mm d^−1	0−30	5
Ws	Fraction of the maximum soil moisture where nonlinear baseflow occurs; Ws > Ds	-	0−1	0.6
D2	Depth of the second soil layer	m	0.1−1.5	0.1
D3	Depth of the third soil layer	m	0.1−1.5	0.2
Expt 1	Variation of Ksat with soil moisture in the first layer	-	-	10.585
Expt 2	Variation of Ksat with soil moisture in the second layer	-	-	10.585
Snow rough	Snow roughness of snow pack	m	0.0001–0.01	0.0001–0.1

Table 3. Performance metrics of snow depth simulations using the VIC model at five climate stations in 17 snowmelt-dominated flood events between February and March in 1959–1994.

	Station
	Freeport	Darlington	Monroe	Martintown	Dodgeville
RMSE (cm)	9.5	10.9	16.6	10.1	12.9
RRMSE (%)	64.0	59.1	77.7	55.4	53.8
B (cm)	−0.5	−2.2	−8.0	−5.0	−8.1
RB (%)	−3.4	−12.1	−37.4	−27.4	−33.8

Figure 5. Observed and simulated maximum snow depths for five stations.

Figure 6. Comparisons between observed data and data simulated by VIC: (a) observed flow peaks and observed flow volumes; (b) simulated flow peaks and simulated flow volumes; (c) observed and simulated flow peaks; and (d) observed and simulated flow volumes.

Table 4. Four-by-four contingency tables for snow depth vs flow peaks.

Station	Obs. flow peak vs Obs. snow depth	VIC flow peak vs Obs. snow depth	Obs. flow peak vs VIC snow depth	VIC flow peak vs VIC snow depth
Darlington
Dodgeville
Freeport
Martintown
Monroe

Figure 7. Average over the three skill score methods presented for each gaging station for observed and VIC data between snow depths and flow volumes.

Figure 8. Average over the five stations presented for each skill score method for observed and VIC data between snow depths and flow volumes.

Table 5. Skill scores showing the categorical correspondence between snow depth and flow volume for observed and model-generated data at five gaging stations. Bold numbers denote the highest and second highest scores.

Comparison	Obs. flow volume & Obs. snow depth			Obs. flow volume & VIC snow depth			VIC flow volume & Obs. snow depth			VIC flow volume & VIC snow depth
Station	Barnston	LEPS	Gerrity	Barnston	LEPS	Gerrity	Barnston	LEPS	Gerrity	Barnston	LEPS	Gerrity
Freeport	0.424	0.434	0.386	0.235	0.271	0.242	0.141	0.118	0.098	0.424	0.461	0.425
Darlington	0.424	0.479	0.438	0.377	0.325	0.333	0.424	0.421	0.464	0.565	0.521	0.516
Monroe	0.282	0.318	0.294	0.282	0.252	0.268	0.094	0.112	0.111	0.471	0.500	0.425
Martintown	0.329	0.465	0.386	0.235	0.225	0.242	0.329	0.366	0.412	0.612	0.641	0.608
Dodgeville	0.424	0.379	0.333	0.329	0.339	0.307	0.329	0.274	0.255	0.424	0.439	0.386

Figure 9. Data-based and model-based averages of the three skill scores between snow depths and flow volumes for early and late periods at Darlington gaging station.

Figure 10. LOOCV box plots of Barnston skill scores depending on stations: (a) Freeport; (b) Darlington; (c) Monroe; (d) Martintown; and (e) Dodgeville. Note that black circles are Barnston skill score results for all 17 year datasets.

Figure 11. LOOCV box plots of Gerrity skill scores depending on stations: (a) Freeport; (b) Darlington; (c) Monroe; (d) Martintown; and (e) Dodgeville. Note that black circles are Barnston skill score results for all 17 year datasets.

Figure 12. LOOCV box plots of LEPS skill scores depending on stations: (a) Freeport; (b) Darlington; (c) Monroe; (d) Martintown; and (e) Dodgeville. Note that black circles are Barnston skill score results for all 17 year datasets.

Park, D. and Markus, M., 2014. Analysis of changing hydrologic flood regime using the variable infiltration capacity model. Journal of Hydrology, 515, 267–280. doi:10.1016/j.jhydrol.2014.05.004

 Web of Science ®Google Scholar