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How do we predict weather and climate?. Review of last lecture. Tropical climate: Land-sea contrasts: seasonal monsoon Extratropical climate: Mean state: westerly winds, polar vortex What is the primary way El Nino affect extratropics? (PNA) - PowerPoint PPT Presentation
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How do we predict weather and How do we predict weather and climate?climate?
Review of last lectureReview of last lecture
Land-sea temperature contrasts: seasonal monsoonLand-sea temperature contrasts: seasonal monsoon
Extratropical climate:Extratropical climate: Mean state: westerly winds, polar vortexMean state: westerly winds, polar vortex The natural oscillations associated with The natural oscillations associated with
strengthening/weakening of polar vortex: AO, NAO, AAOstrengthening/weakening of polar vortex: AO, NAO, AAO Effect of global warming on polar vortexEffect of global warming on polar vortex What is the primary way El Nino affect extratropics? (PNA)What is the primary way El Nino affect extratropics? (PNA)
AstronomyMeteorologyAgriculture
FoodWeather
CommunicationTransportationEngineeringMaterialsEnergy
EnvironmentHealth
ComputerMechanicsChemistryPhysics Math
Earth SciBiology
0 500 1500 20001000500BC
Human Needs
Science
Middle Ages
Archimedes
Socrates Galileo
BrunoMadam Curie
Einstein
Time
Spirit of Independent Thinking
Individual Objects
Organic System
The Global Climate System - Atmosphere, The Global Climate System - Atmosphere, ocean, biosphere, cryosphere, and geosphereocean, biosphere, cryosphere, and geosphere
RadiationCloud/precipitation
Shallow convection Boundary layer turbulence
Mesoscale convective system ThunderstormTornado
Heat waveMidlatitude cycloneAtmospheric riverTropical cyclone
Diurnal variation
Madden-Julian Oscillation Tropical wavesAnnular modes
100,000yr100yr10yr1yr1mon1day1min1sec10-15sec
Global Climate System
Globe
Continent
State
City
Football field
1 mm
1 m
Spatial Scale
Time Scale
10-4 m Composition
Monsoon
ENSOQBO
Global warmingMulti-decadal Oscillation
Ice ageGlacial cycleAbrupt change
Video: Video: Predicting the forces of NaturePredicting the forces of Nature
https://www.youtube.com/watch?v=aC-q0CkBYIA https://www.youtube.com/watch?v=aC-q0CkBYIA
(-6:00, 38:40-)(-6:00, 38:40-)
General Circulation Model: BasicsGeneral Circulation Model: Basics
• General circulation models are systems of differential equations based on the General circulation models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. basic laws of physics, fluid motion, and chemistry.
• Scientists divide the planet into a 3-dimensional grid (Scientists divide the planet into a 3-dimensional grid (100-500 Km wide100-500 Km wide), apply the ), apply the basic equations within each grid and evaluate interactions with neighboring points. basic equations within each grid and evaluate interactions with neighboring points.
General Circulation Model: General Circulation Model: Basic equations Basic equations
This set of equations is This set of equations is called the called the Navier-Stokes Navier-Stokes equationsequations for fluid flow, for fluid flow, which are at the heart of which are at the heart of the GCMs.the GCMs.
There are other There are other equations dealing with equations dealing with the conservation of Hthe conservation of H22O, O,
COCO22 and other chemical and other chemical
species.species.
(Conservation of monmentum)
(Conservation of mass)
(Conservation of energy)
Supercomputer power (FLOPS)Supercomputer power (FLOPS)
WorldWorld’’s Major Global Climate Modelss Major Global Climate Models
General Circulation Model: UsagesGeneral Circulation Model: Usages
Global climate projections
Global weather predictions
Global climate predictions
Required model complexityRequired model complexity
Global weather prediction (up to 1 month) - Global weather prediction (up to 1 month) - Atmospheric GCM (AGCM)Atmospheric GCM (AGCM)
Global climate prediction (beyond 1 season) Global climate prediction (beyond 1 season) - Coupled ocean-atmosphere GCM (CGCM)- Coupled ocean-atmosphere GCM (CGCM)
Global climate projections (beyond 10 years) Global climate projections (beyond 10 years) - Climate system model (CSM)- Climate system model (CSM)
Coupler .
Land Sea Ice
Atmosphere
Ocean
Framework of Climate System ModelFramework of Climate System Model
Example: Example: Land ModelLand Model
(From Bonan 2002)
Video: Climate Modeling With Video: Climate Modeling With SupercomputersSupercomputers
http://www.youtube.com/watch?v=izCoiTcsOd8http://www.youtube.com/watch?v=izCoiTcsOd8
Mesoscale modelMesoscale model
Mesoscale: 1 Km- 1000 Km, 1 min - 1 dayMesoscale: 1 Km- 1000 Km, 1 min - 1 day Grid size: 1 Km - 10 kmGrid size: 1 Km - 10 km Three characteristics: Three characteristics:
Non-hydrostatic processesNon-hydrostatic processes
Nested gridNested grid
Topography effectsTopography effects
Mesoscale model: Non-hydrostic processesMesoscale model: Non-hydrostic processes
Non-hydrostatic processes need to be consideredNon-hydrostatic processes need to be considered
Mesoscale model: Nested gridMesoscale model: Nested grid
Finer grids in regions of interestFiner grids in regions of interest
Mesoscale model: TopographyMesoscale model: Topography Topography strongly influences mesoscale processes Topography strongly influences mesoscale processes
(e.g. land breeze, mountain breeze) (e.g. land breeze, mountain breeze)
SummarySummary
General circulation models: Grid size. 3 General circulation models: Grid size. 3 usages. Name of the basic set of equations. usages. Name of the basic set of equations.
4 components of the climate system model.4 components of the climate system model. Mesoscale models: grid size. 3 characteristics.Mesoscale models: grid size. 3 characteristics.