Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society What is a climate model? What is a climate model? If we cannot predict weather, how can we predict climate?

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Reading for Week 6 Lecture 11 What is a climate model? RG GW Chapter 5 IPCC WG1 Chapter 8, FAQ 8.1 How Reliable Are the Models Used to Make Projections of Future Climate Change? – ftp://iges.org/pub/emilia/CLIM101_2010/reading/IPCC_ WG1_FAQ8.1.pdf

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Substitute for reality Closely mimics some essential elements Omits or poorly mimics non-essential elements What is a Model?

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society What is a Model? Quantitative and/or qualitative representation of natural processes (may be physical or mathematical) Based on theory Suitable for testing “What if…?” hypotheses Capable of making predictions

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Input DataModelOutput Data Tunable Parameters What output data might we consider for a typical climate model? What input data might we consider for a typical climate model? What are the tunable parameters of interest? What is a Model?

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Input DataModelOutput Data Tunable Parameters What is a Model? Temperature, Pressure, Humidity, Wind Velocity, Salinity, Ice Mass, … Averaged by Day, Month, Season, Year, … Need verification with obs Energy flux from Sun Atmospheric constituents (CO 2, etc.) Landscape features (geography, topography, land use, etc.) Initial conditions of all predicted variables Properties of: Clouds, Ice, Aerosol …

CLIMATE DYNAMICS OF THE PLANET EARTH S Ω a g T4T4 WEATHERWEATHER CLIMATE. CLIMATE. hydrodynamic instabilities of shear flows; stratification & rotation; moist thermodynamics day-to-day weather fluctuations; wavelike motions: wavelength, period, amplitude S,, a, g, Ω O 3 H 2 O CO 2 stationary waves (Q, h*), monsoons h*: mountains, oceans (SST) w*: forest, desert (soil wetness)  (albedo)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate System Theory Discretization

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate System Theory Discretization

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society (approximation) Mass conservation Energy conservation Newton’s law  = p / p s

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate System Theory Discretization Equations of motions and laws of thermodynamics predict rate of change of: T, P, V, q, etc. (A, O, L, CO 2, etc.)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate System Theory Discretization Equations of motions and laws of thermodynamics predict rate of change of: T, P, V, q, etc. (A, O, L, CO 2, etc.)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Discretization Atmosphere and ocean are continuous fluids … but computers can only represent discrete objects

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Discretization Atmosphere and ocean are continuous fluids … but computers can only represent discrete objects

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Equations of motions and laws of thermodynamics to predict rate of change of: T, P, V, q, etc. (A, O, L, CO 2, etc.) 10 Million Equations: 100,000 Points × 100 Levels × 10 Variables With Time Steps of: ~ 10 Minutes Use Supercomputers What is a Climate Model?

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Numerical Weather Prediction 1.Determine (continuous) equations to be solved – Equation of state or Ideal Gas Law (Boyle’s Law relates P  V, Charles’ Law relates V  T, Gay-Lussac’s Law relates T  P) – Conservation of mass (dry air, water) – Conservation of energy – Conservation of angular momentum – Result: set of coupled, nonlinear, partial differential equations 2.Discretize the equations for numerical solution (typically requires computer) 3.Measure current state of global atmosphere to obtain initial conditions 4.Solve the initial value problem to produce a forecast 5.Take into account uncertainty in measured atmospheric state by repeating step 4 over an ensemble of slightly different initial conditions

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate Predictability: Averages in space and/or time are more predictable than instantaneous values. Energy balance sets the range of weather variation.

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Science Predictability in the Midst of Chaos: A Scientific Basis for Climate Forecasting 23 October 1998, Volume 282, pp J. Shukla Soil Wetness SST Anomalies ( o C)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society 1998 JFM SST [ o C] JFM SST Climatology [ o C] 1998 JFM SST Anomaly [ o C] El Nino/Southern Oscillation

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society El Nino/Southern Oscillation

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Rainfall Anomalies

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society ca 2000 AGCM Model Simulation of ENSO Effects 500 hPa Height Anomalies (ACC = 0.98)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Moore’s “Law” IPCC-1 IPCC-2 IPCC-3 IPCC fold jump since 1st IPCC fold jump in last 30 years Latest advance due to dual-core chips Near-term advance w/quad-core chips

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society John von Neumann Seymour Cray & Cray-1 ENIAC IBM 360 Cray-2 Columbia NASA

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Climate Models circa early 1990s Global coupled climate models in 2007 and new ESMs New decadal prediction models Global coupled models in 5 yrs post-AR5 ~500 km~100 – 200 km ~50 km~10 km

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society European Heat Wave 2003 European Heat Wave 2003

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society JJA 2003 SST Anomaly

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society JJA obs OBS.SST-CLIM.SST exp. result significant at more than 90% sig.lev.

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society J. Shukla, T. DelSole, M. Fennessy, J. Kinter and D. Paolino Geophys. Research Letters, 33, doi /2005GL025579, 2006 Climate Model Fidelity and Projections of Climate Change

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Regional Climate Change – Beyond Today’s Models’ Ability?

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Annual Mean Precipitation Change Europe: 21 st C minus 20 th C T159 (125-km)T1279 (16-km) “Time-slice” runs of the ECMWF IFS global atmospheric model with observed SST for the 20 th century and CMIP3 projections of SST for the 21 st century at two different model resolutions The continental-scale pattern of precipitation change associated with global warming is the same, but the regional details are quite different, particularly in southern Europe.

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global SocietySummary 1.Weather prediction depends on initial conditions (global observations). 2.Short-term climate (seasonal-decadal) depends on boundary conditions (SST, soil wetness, snow, sea ice, etc.), which depends on ocean-atmosphere interactions. (natural forcings: sun, volcanoes, etc.) 3. Long-term climate change depends on “external” forcing (Human: greenhouse gases, land cover change, etc.)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Dynamics Physical processes Climate System Modeling Atmospheric General Circulation Model Basic Equations

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Weather Prediction Future pressure = current pressure + (rate of change of pressure) x  t Future temperature = current temp. + (rate of change of temp.) x  t Current pressure & temperature: use global observations For rate of change: use mathematical equations For producing forecast: use supercomputers

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Sea Level Pressure (mb) & Precipitation Rate (mm/12Hr) 00Z Tue 10 Nov 1998

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Sea Level Pressure (mb) & Precipitation Rate (mm/12Hr) 12Z Tue 10 Nov 1998

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Sea Level Pressure (mb) & Precipitation Rate (mm/12Hr) 00Z Wed 11 Nov 1998

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society 2003 Heat wave hits Europe 30,000 people die in Western Europe observations HadCM3 Medium-High (SRES A2) s 2060s Temperature anomaly (wrt ) °C

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Courtesy of P. Houser (GMU)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society 200 km

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Geographic resolution characteristic of the generations of climate models used in the IPCC Assessment Reports: FAR (IPCC, 1990), SAR (IPCC, 1996), TAR (IPCC, 2001a), and AR4 (2007). The figures above show how successive generations of these global models increasingly resolved northern Europe. These illustrations are representative of the most detailed horizontal resolution used for short-term climate simulations. The century-long simulations cited in IPCC Assessment Reports after the FAR were typically run with the previous generation’s resolution. Vertical resolution in both atmosphere and ocean models is not shown, but it has increased comparably with the horizontal resolution, beginning typically with a single- layer slab ocean and ten atmospheric layers in the FAR and progressing to about thirty levels in both atmosphere and ocean.

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Computing Capability & Global Model Grid Size (km) Peak Rate:10 TFLOPS100 TFLOPS1 PFLOPS10 PFLOPS100 PFLOPS Cores (1 st year available) 1,400 (2006) 12,000 (2008) ,000 (2009) ,000 (2011) 6,000,000? (20xx?) Global NWP 0 : 5-10 days/hr (~20X10 6 points) Seasonal 1 : days/day (~20X10 6 points) Decadal 1 : 5-10 yrs/day (~2X10 6 points) Climate Change 2 : yrs/day (~0.5X10 6 points) Range: Assumed efficiency of 10-40% 0 - Atmospheric General Circulation Model (AGCM; 100 levels) 1 - Coupled Ocean-Atmosphere-Land Model (CGCM; ~ 2X AGCM computation with 100-level OGCM) 2 - Earth System Model (ESM; ~ 2X CGCM computation) * Core counts above O(10 4 ) are unprecedented for weather or climate codes, so the last 3 columns require getting 3 orders of magnitude in scalable parallelization (scalar processors assumed; vector processors would have lower processor counts) Thanks to Jim Abeles (IBM)

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society Center of Ocean-Land- Atmosphere studies Projection of Global Warming Mean of 15 Models Surface Air Temperature Difference (Sresa1b YR ) minus (20c3m ), Global Average = 2.61

Center of Ocean-Land- Atmosphere Studies CLIM101: Global Warming - Weather, Climate and Global Society IPCC º C Increase in Surface Temperature Observations Predictions with Anthropogenic/Natural forcings Predictions with Natrual forcings