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| Snow depth
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| Definition |
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Vertical extension of snow at defined sample points.
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| Rationale |
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Snow depth observations are important in assessing winterkill of agricultural crops, influence of surface energy exchange and managing snow removal.
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| Users |
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Modellers, climate, hydrology, climate impact analysts, change detection analysts, agriculturists, transportation specialists and recreational planners.
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| Assessment method |
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Tiers 1-4: direct field measurements (points, snow courses);
Tier 5: inferred from satellite data. The estimation based on optical data varies with cover type and is not generally reliable. Snow depth could be inferred using satellite microwave measurements if snow density distribution is known (see Snow Water Equivalent variable sheet).
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| Units of Measure |
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cm
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| Frequency of measurement |
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Daily
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| Spatial resolution |
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Point measurements at existing climate and synoptic stations (GCOS surface network).
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| Accuracy/precision required |
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± 2 cm at depths up to 20 cm;
± 10% of absolute at depths greater than 20 cm.
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| Associated measurements |
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Temperature and precipitation including snowfall.
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| Present status |
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Manual daily snow depth observations have been a standard observation at synoptic and climatic stations. Automatic snow depth sensor observations are being made at a few fully automated synoptic stations. There are experimental satellite derived estimates being made from microwave sensors.
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| R and D needed |
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- Evaluation and improvement of automatic depth measurements;
- Definition of observation standards for manual and automatic stations;
- Implementation of automatic sensor observations.
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