Water Cycle Dynamics in a Changing Environment Advancing Hydrologic Science through Synthesis
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Transcript of Water Cycle Dynamics in a Changing Environment Advancing Hydrologic Science through Synthesis
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Water Cycle Dynamics in a Changing EnvironmentAdvancing Hydrologic Science through Synthesis
to organize and employ synthesis activities to produce transformational outcomes that will be utilized to improve the predictability of water cycle dynamics in a changing Earth environment.
Objective
Hydromorphology: Human-Nature Interactions #1. Interactions between hydrosphere and biosphere processes #2. Interactions of landscape processes within intensively managed watersheds Evolution, structure and function of hydrologic subsystems in hillslopes Stochastic transport in heterogeneous media
Research Themes
Principal Investigators: Murugesu Sivapalan, Praveen Kumar, Bruce Rhoads, Don Wuebbles
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Unprecedented Types, Rates, Scales, and Magnitudes of Change
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Limits to predictabilityPrediction means making probabilistic statements about future system states given the current and past observed states and our understanding of how nature works. The four classical limits to predictability are (NRC WSTB, 2002):• Type I – uncertainty in the characterization
of initial states• Type II – uncertainty in the characterization
of the dynamics at the interfaces• Type III – uncertainty in the
characterization of model parameters• Type IV – uncertainty or inadequacy of
characterization of critical processes, process interactions and feedbacks
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Working Hypotheses: Patterns
• Patterns help us to reduce the complexity through reduced dimensionality, and thus help to improve predictions
• Patterns (both observed and so far unobserved) are emergent properties arising out of complex interactions and feedbacks between a multitude of processes.
• Study of patterns (how to describe them, why they emerge, their impact on the overall response) yields new insights and lead to increased understanding.
• Study of observed patterns (why they emerge) may give insights into unobservable or as yet unobserved patterns, and help to make improved predictions
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Theme #1: Interactions between hydrosphere and biosphere processes
Water balance partitioning at the catchment scalePeter Troch, Ciaran Harman and Sally Thompson
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
The Horton Index
Precip
“Fast” runoff
“Slow” runoff
ET
Wetting
Annual Evapotranspiration
Annual WettingHI =
Proportion of available water that is vaporized
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Horton Index vs. Humidity IndexBetween catchments
Troch et al., 2009 (HP)
Between yearsPattern that intrigues…..
Humidity Index =Annual Precipitation
Annual Potential Evaporation
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Horton, 1933 (AGU)
H constantVW
V : Growing-season vaporization (E+T)W : Growing-season wetting (P-S)
“The natural vegetation of a region tends to develop to such an extent that it can utilize the largest possible proportion of the available soil moisture supplied by infiltration” (Horton, 1933, p.455)
Pattern that intrigues…..
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
MOPEX catchments
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Models of landscapes as nonlinear filters Penman Monteith
Model
Rn VPD LAI U P T
Emax
E
T
Interception Model
PPT
Runoff
Drainage
Infiltration
Multiple Wetting Front Model Root Water Uptake Model
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
FLUXNET sites
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Hypothesis
?
?
?
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Theme #2: Interactions of landscape processes
within intensively managed watersheds
Sediment and Contaminant Dynamics Across Scales Nandita Basu, Ciaran Harman, Sally Thompson
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Patterns that intrigue…..
Nitrate load-discharge relationships across Mississippi
Sediment load-discharge relationships
Why are they linear?Or,
Why are watersheds chemostatic?At what scale are they chemostatic?
And why?
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Filtering of solute variability across scales: Study sites
Mississippi Basin
Little Vermilion
Single Tile Drain
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Landscape and Network Filtering of Sediment Transport: Study Sites
Goodwin Creek, Mississippi Rio Isabena, Spain
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Hypothesis: Landscapes act as cascading,coupled filters
Observed “patterns” are windows into this filtering
2009 Hydrologic Synthesis Reverse Site Visit – Arlington VA
Summary• Summer institute: grassroots type organization – team based,
egalitarian, targeted and yet free to explore alternative ideas or approaches, trail blazing
• Data based: recognize/extract patterns from data• Patterns needing a multitude of perspectives from different disciplines
to explain or interpret• Interpretation of patterns using parsimonious models: a top-down
approach• What are the minimum processes needed to describe strong physical, chemical
and biological coupling over a wide range of spatial and temporal scales?• How do complex highly heterogeneous physical, chemical and biological systems
respond to changes in forcing behavior and system structure?• Comparative hydrology: develop generalizable insights through
comparisons and classification• Modeling of landscapes as nonlinear hierarchical filters –
potentially transformative approach