Climate and the local water balance
29 important questions on Climate and the local water balance
Getting all properties on soil moisture right, will that give you proper discharge and streamflow dynamics estimation?
Model that gets evaporation, root zone, etc right, will it get the mean streamflow right?
How much water leaves the catchment via evaporation vs. Streamflow? Why else is evaporation important for hydrology?
Evaporation changes due to climate change have a large effect on water availability.
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Why is recession faster in summer?
Name a pro and con for all 5 measurement manners of evapotranspiration
+ Cheap, robust
- Complex relation to actual ET
Lysimeter (cylinder):
+ Accurate, high-resolution
- Expensive, heavy
Catchment water balance:
+ Accurate, large sampling volume
- Temporal resolution: several years (1-5 years), assume no storage change (dS/dt = 0)
Eddy covariance:
+ All ecosystems
- Expensive, footprint definition (measures turbulence, so wind-dependent which can pose a conceptual problem with changing directions and speed, etc.)
Thermal remote sensing:
+ Coverage (global through satellites)
- Land surface temperature is indicative of balance, but not directly related to evaporation
How is evaporation/ET monitored in NL? What's a trend in ET monitoring?
There's interest in ET monitoring and they sell, but be very critical on their quality!
Name a eddy covariance trend
Thus also be critical of their quality/representation!
Name several trends in long-term soil moisture monitoring networks
Mention the main observations/rank the ET rates of bare soil/snow/latitude wise/ET...?
Based on what would we partition between transpiration and evaporation?
How does the reduction in ET look like and how should we model this? (min 44)
Transitional climate: dry summer, wet winters.
!! At low soil moisture, uptake from plant roots can no longer satisfy the atmospheric demand (PET).
!!Important graph on SMC-EF relation: dry-transitional-wet
Stress factor beta
Question on min 60-62 (non)linear relation:
Why do ET linearly decrease over time in drying conditions? How does this relate to different environments?
Forest: ET decay is slower, vegetation has access to more storage.
Explain the differences between saturated, field capacity, typical and wilting point conditions and how they relate to capilary water?
Below FC, water is too tightly bound to the soil particles to move by itself.
ADDD
Mention 5 SM metrics, which is most often used?
- Absolute water content [mm]
- Ratio of saturation or wetness [mm/mm]
- Volumetric water content [mm/mm]
- SM potential (very non-linear scale!, negative scale means the suction is very strong)
- SM index (SMI) [-]
Smt with curvature of water surface, particle size and K
Explain power-law/the relation between volumetric water content and unsaturated K? Give also the formula?
Amount of non-linearity is a function of the soil type
Add formula.
How is field capacity related to SM and Ksat?
- This FC can be seen in time series, e.g. After a few days of drainage.
Why does K increase with increased vol. Water content?
How does drainage capacity relate to typical range in daily rainfall?
What is the soil moisture loss function made up of?
SM does not remain in equilibrium between FC and critical point, why and what is the result?
Winter: above FC
Summer: decreases to critical SMC or below. It can stay below SMC.
A bimodal state preference (wet and dry end): below critical SMC and above FC.
What is available storage?
Typical root depth?
Why fast response in Cork/wet situation and how is this visible in the graph?
Unless when you have long dry periods, an ET dominated regime could occur.
Faster, bc later slope is much steeper than lsope in beginning. Thus stronger response in drainage than in ET. Drainage responds more non-linear! (see min 99)
Give a short summary of the lecture, use the words: energy limited, water limited, SM, ET, drainage
Why is there a horizontal compartment in the loss function?
Explain how an analytical expression for stochastic rainfall can be derived conceptually? Min 100-105.
How does climate determine the partitioning of water? --> goal for practical & Min 105-107
Explain the main concepts of the Budyko curve?
The further you move to the right, you will approach 1 on y-axis: the drier, the more you get to 1.
Humid environment: ETact=ETpot, the more humid, the less likely you'll get below critical SMC.
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