Transcript Document

Engineering Design and Climate:
Change
and
Variability
Ana P. Barros
March 7, 2005
1. Back to the early 20th century…
(engineering thinking)
Climate variability – refining the concept
From periods
to cycles of varying periodicity
to modes of variability and nonstationary
Space-Time Variability and Interconnectedness
(the missing science piece)
Design Implications
2. Practice, Science,
Risk Assessment and Man-Made Change
(engineering doing)
3. Design for the Future
(engineering renaissance)
Water Resources Management and Engineering Paradigm
“We the Governors of the States and Territories of the United
States of America, in Conference assembled, do hereby declare
the conviction that the great prosperity of our country rests upon
the abundant resources of the land chosen……..”
“These natural resources include the land on which we live….
The living waters which fertlize the soil, supply power, and
form great avenues of commerce…..The forests …..”
“We recognize in our waters a most valuable asset of the People
of the United States…… enactment of laws … irrigation, water
supply, power production, navigation, to the end that navigable
and source streams may be brought under
control
complete
and be fully utilized for every purpose”
Declaration of the Conservation Conference, May 15, 1908
The beginning of the race …
“Is it possible that climatic oscillations can exist alone (with no effect
upon anything else) ? … So far, we are completely in the dark as the
plotting of meteorological observations alone will not determine it.”
Brückner, 1890
“For instance, a sharp controversy has raged for several years between
States bordering on the Great Lakes and the City of Chicago ..cause
Abnormally low lake levels…The question is whether the recurring
variations in lake level are another of the …climatic cycle established
by Brückner.”
Streiff, 1926
Chronology …
Huntington, 1914 (tree rings)
………
Streiff, 1926 (Nile floods, nonstationary)
Streiff, 1928
……….
Shuman, 1931 (lake levels)
………
Gilette, 1935 (rainfall)
………
What they were saying….
“ Most of our park systems drive-ways, and roads of all types for
auto travel, in the various States, have been completed within the past
30 years, namely, beginning at the very lowest point of our climatic
swing (1900 and 1910). There is every reason to believe, therefore,
as the next 20 years comes on apace, we will witness considerable
damage to work done during this past regime of weather.”
Jesse W. Shuman, C.E
Monthly Weather Review, June 1931
“..It would seem as though the mean annual levels of Lake Ontario
Were due for an oscillating reduction (first, high, then lower,
but generally downward) for a few years, then an upward trend till 1940…”
Shuman, 1931
The prediction ….
“We are in the middle of one of those long dry periods in history,
which in old times caused famines migrations and wars.
averaged by decades, rainfall in general will be subnormal for
about 40 years.”
Gillete, June1935 (AMS)
Water Works and Sewage, August 1935
Andover
Oxford
70-80 years
“The design of works for control of water
requires the estimate of future runoff.
This is usually done by
taking the probability of occurrence a priori equal to that a posteriori,
which procedure often based on short records often does not take into
consideration the oscillations in precipitation which occur.
A better procedure is
to analyze these trends and oscillations and
to estimate their extrapolation for such length of time as
may be involved in the project under consideration.”
Abraham Streiff, C. E.
Monthly Weather Review, March 1928
1. Back to the early 20th century…
(engineering thinking)
2. Practice, Science,
Risk Assessment and Man-Made Change
(engineering doing)
Predictability and Uncertainty
Precipitation, Runoff
“Extremes”
Adaptation
3. Design for the Future
(engineering renaissance)
Precipitation Processes
Clausius-Clapeyron Equation
vapor pressure
saturation vapor pressure
Clouds
???
(3)
e
Evaporation
Heating
(2)
Td
(1)
T
Temperature (T)
Cooling / Lifting
Rainfall
Freshwater Resources
EvapoTranspiration
Evaporation
Precipitation
70%
10%
Runoff
Soil Moisture
Blue
Green
Virtual
Report of the Water Sector Assessment
Team of the National Assessment of the
Potential Consequences of Climate
Variability and Change
September 2000
http://www.nacc.usgcrp.gov
Evidence…
•There is evidence of historical trends of both increasing and decreasing
precipitation in different parts of North America since 1900. The
intensity of precipitation has increased for very heavy and extreme
precipitation days.
•Vegetation is blooming earlier in spring and summer and
continuing to photosynthesize longer in the fall (medium
confidence).
•The flood related consequences of climate change may be as
serious and widely distributed as the adverse impacts of droughts
and there is more evidence now that flooding is likely to become a
larger problem in many temperate regions, requiring adaptations not
only to droughts and chronic water shortages, but also to floods and
associated damages, raising concerns about dam and levee failure.”
Vegetation
and
Hydrologic Resilience
San Joaquin Valley
3000 BC
Cedars of Lebanon
Precipitation
Soil
Vegetation
Runoff Fraction
Vegetation
Control
Monongahela River Basin
1988 Drought
April-August
Soil
Water
Control
Evaporative Fraction
May 13, 2001
Photo-Op with the the president of the ANEEL
The energy crisis: What went wrong
Hydroclimatology….
Reservoirs
Rainfall
SON DJF MAM JJA
Spring
Fall
Summer
“Winter”
Time
Hydrometeorological Asymmetry…..
(Land Controls on Space-Time Variability)
Streamflow = Surface Runoff + Subsurface Runoff +Baseflow
Shifts in Seasonality …..
Summer Rainfall
Fall Rainfall
Evapotranspiration
Rainfall Intensity
Subsurface Runoff
Temperature
Diurnal Cycle
Reservoirs
Prediction…
1) Uncertainty of fact
Prediction…
2) Mandelbrot uncertainty
Observations
Joseph effect
*Low-Frequency Analysis
*Noah Effect
Joseph Effect
1950
1970
Pe=1: 15,000 years
Multifractals as Design
Alternative to Probable
Maximum Precipitation
Estimation with known
Risk
Douglas and Barros, 2003
Pe=1: 1 million years
Noah Effect
Multifractals
And Small Dam Design
Current Best
Practice Estimate
Known
Risk
Global Warming and Uncertainty
Noah (?) , Joseph (?), Noah-Joseph (?) Effect
State (higher-order moments)
Tails
Mean
1. Back to the early 20th century…
(engineering thinking)
Climate variability – refining the concept
From periods
to cycles of varying periodicity
to modes of variability and nonstationary
Space-Time Variability and Interconnectedness
(the missing science piece)
Design Implications
2. Practice, Science,
Risk Assessment and Man-Made Change
(engineering doing)
3. Design for the Future
(engineering renaissance)
Recommendations….
A continued reliance solely on current engineering practice may lead
us to make incorrect – and potentially dangerous or expensive – decisions.
These systems were designed and for the most part are operated assuming
that future climatic and hydrologic conditions will look like past conditions.
Accordingly, two of the most important coping strategies must be to try to
understand what the consequences of climate change will be for water
resources and to begin planning for and adapting to those changes.
It is vital that uncertainties not be used to delay or avoid
taking certain kinds of action now. Water managers and policymakers
must start considering climate change as a factor in all decisions about water
investments and the operation of existing facilities and systems.
(Barros and Evans, 1996)
Challenges and Opportunities
Paradigm Shifts…
•Control ---- Management
•Reactive (static) ---- Adaptive (dynamic) Design
•Modeling - - - Monitoring
•Inter/Transdisciplinarity
•Complex Multiscale Dynamical Systems
Science & Technology
•Understanding (new science)
•Methodologies and Metrics
•Space-Time Observations (from Remote Sensing)
•Computational Power
•Information Technology
Engineering is a “Process” ….
*Monitoring (data)
*Analysis
Terrestrial Hydrological Cycle at
spatial and temporal scales needed to detect
change in the dynamics of limiting physics;
* Synthesis, Integration & Adaptation
Resilient Design Embraces Variability