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Integrating climate and weather
products in Water Resources
Management
by
Francis Mutua
University of Nairobi
Climate and Water Resources
 The climate of the Earth is
controlled mainly by the
energy from the sun
• Atmosphere
• Hydrosphere
• Lithosphere
• Biosphere
 Anthropogenic
forces
change the equilibrium
SUN’S
ENERGY
THE CLIMATE SYSTEM
ATMOSPHERE +
STRATOSPHERE
 Moisture
 Pressure
 Temperature
 Energy/dynamics
 G.H. gases
 Etc
LAND
 Terrestrial water
resources
 Topography
 Glaciers + Ice-caps
 Bio-systems
 Etc






OCEANS
Temperature
Salinity
Energy/dynamics
Glaciers + icecaps
Bio-systems
Etc
Climate variability
• Climate variability is strongly linked to variations in the the solar
output – variability with time-scales > 1 yr.
etc.
Examples: ENSO (3-6 yrs), sunspot activity (11 yrs), QBO
(2
yrs),
• The oscillation of the earth around the sun (Time-scale =
seasons): Seasonality: notably in precipitation, temperature
humidity and evaporation
• The
combination
yields
seasons
NORMALABN in precipitation
:
BNNEAR-
• Climate variability introduces a corresponding variability in the
hydrological cycle
Climate Variability and Water Resources
• Hence climate variations have significant consequences on the
quality and quantity of water in all hydrological regimes.
• Climate variability is the major cause of the extremes which are
observed in hydrological systems: floods and droughts
• Thus floods (quick onset) and droughts (slow onset) hazards are
part of the climate systems and therefore unavoidable
• However, they need not become disasters because it is possible
to to be prepared for them (especially drought hazards)
• Often, they turn into disasters
– Famine and crop failure
– Deaths (humans and livestock)
– Adverse economic impacts and impoverishment
– Conflicts
• All because climate and weather information and products are
not adequately factored into national disaster management.
Climate Change
• Climate change
– The IPCC projections of air temperature change over the next
century, following 2xCO2 is an increase of 1o to 3.5oC, with a "best
estimate" of 2oC Ppt, Temp, winds, Press., Evp, etc.
– The manifestation of climate change would imply that the water
resources would respond with the corresponding irreversible trend
(and perhaps higher variability) as with the climate.
• Other forcings which exacerbate the impacts of climate change on
water resources
– population pressure
– land use and land management
Ordinarily
exacerbate
– agricultural and industrial developments
water related disaster
risks (floods+droughts)
– domestic attitudes
Now add climate change!
– recreation demands, etc
Scenarios for Assessing Impacts of
climate change on Water Resources
• Uncertainties
– Future emissions (SRES
story-lines)
– Future concentrations
(climate  CO2 cycle
chemistry physics)
– Response of climate (Time
lags)
– Natural variability?
– GCMs
 GCM/RCM
 Synthetic/Incremental
 Analoque
 Downscaling
GCMRegional
EMISSIONS
Scenarios frompopulation, energy,
economic models
CONCENTRATIONS
CO2, methane, sulphates, etc
Carbon cycle and chemistry models
Synthetic Climate
Change Scenarios
(Thresholds)
GLOBAL CLIMATE CHANGE
Global Climate Models (GCMs)
Statistical Downscaling of
GCMoutputs to Regional
outputs
Regional Climate
Models (RCMs)
(MM5, PRECIS, etc.
Regional Climate Change Scenarios
IMPACTS
Analogue Climate
Change
Scenarios
Integrating climate-change in water
resources management
 CALIBRATION OF THE HYDROLOGIC SYSTEM MANAGEMENT
Climate Input
(Historical Data)
Baseline characteristics
 Soils
 Geology
 Topography
 Vegetation
 Land-use
 etc
Water Resources
Characteristics
(Historical Data)
(Calibration and Verification of the Water Resources Model)
(Use of the Calibrated Model to Assess Impacts of Climate Change on Water Resources)
 FACTORING CLIMATE CHANGE IN WATER RESOURCES SYSTEM
MANAGEMENT
Climate
Change
Scenarios
as Input
Basin scenarios
 Soils
 Geology
 Topography
 Vegetation
 Land-use
 etc
Assessment
of Impacts of
Climate and
Basin
Change on
Water
Resources
characteristic
s
Improved water
resources management
Plans for ground
and surface
water
developments
Coastal waters
 Hazards
Integrating Climate and weather in
Water Resources Management
CLIMATE AND WEATHER PRODUCTS AND
INFORMATION
Climate variability
(ENSO, Sunspot activity,
SEASONAL
Synoptics, QBOs, etc)
OUTLOOKS
Climate-Change (Scenarios)
HYDROLOGY
and/or
Hydraulics
(Modeling)
Physical basin characteristics
and scenarios
 Soils
 Land-use
 Vegetation and land
cover
 etc
Socio-economic
factors +scenarios
Hydrologic outlooks:
 Surface and groundwater deficit/excess
(flood & drought hazards)
 Warnings, awareness and preparedness
 Early warning systems
Climate integrated and improved water resources management with
disaster risk mitigation strategies