History of Climate Modeling

Art of Climate Modeling Course from UC Davis ATM 265 (Paul Ullrich)

Over the course, we will discuss:

• Global Atmospheric Models
• Numerical discretizations in horizontal, vertical, and temporal dimentions
• diffusion filters and fixers
• kinetic energy spectra
• physical parameterizations
• computing on large-scale parallel systems, model evaluation and inter-comparison

Global Earth-System Modeling

• understanding circulation of the atmosphere
• later ocean and cryo models were develooped
• used as labs for answering science of weather/climate drivers, used to model other planets’ atmospheres.

Global Model has physical horizontal and vertical grid (over temporal aka time)

Anatomy of Atmospheric Model

1. Dynamic Core (horizontal transport, resolved-scale vertical motion) include: pressure, adiabetic processes, temperature, diffusion, wind velocity
2. Physical Parameterizations (moisture, ice, land, chemistry, radiation, etc.) include: Radiation, Frcition, Humidity, Clouds, Precipiation, Cumulus Convection, Evaporation, Sensible Heat Flux, Ground Roughness, Ground Temperature, Snow, Ground Humidity, Melting

Climate models and numerical weather prediction models used to be different, one for long time scales and over global scale, the latter more about faster computation, high spatial resolution (smaller spaces) and minimal physical parameterizations. But the lines have blurred.

Global and Regional Models (have lateral boundaries and captures a portion of the Earth’s surface).

Variable Resolution Models are increasingly popular to focus on certain geographic areas while not ignoring the greater factors of other parts of the global, models include: conformal cubed-sphere, non-conforaml cubed sphere, and centroidal vornoi tessellation

History

1600s — barometer (pressure) and hygrometer (humidity)

1700s — thermometer (fahrenheit scale),
French chemist Antonie-Laurent de Lavoisier made daily measurements of air pressure, moisture content, wind speed, direction; he is also known as father of modern chemistry and for first version of law of conservation of mass, definition of metric system, first exhaustive list of chemical elements

1800s — electric telegraph invention allowed communication of weather conditions over vast geographical area, the idea of national meteorology system started to track measurements (but without delivering mass weather forecast), modern meteorology started with a naval disaster of a storm that destroy ships, investigated by Urbain Le Verrier of Paris Observatory, leading to national storm warning service;
Robert FitzRoy used telegraph system to produce first synoptic charts to coin ‘weather forecast’
Internationl Meteorlogical Organization formed in Vienna; US Army Signal Corp forerunner for National Weather Service, issued first hurricane warning.

1900s — first set of equationsof motion for atmosphere using theory of fluids; Lewis Fry Richardson, proposal of materical technique for systematic forecasting by numerical methods, but his primitive numerical method swere very inaccurate, due to missing smoothing methods, this dramatic failure was ok because after finding the smoothing, the corrections showed forecast was essentially accurate. he first imagined a chamber of ‘mathematician calculators aka people’ doing math to predict weather, even though it would take forever.

1940s John von Neumann used computing systems to compute explosion behaviors and encouraged use of computers to model atmosphere

1950s first GCM developed by Norman Phillips in 1955 Princeton U, Smagorinsky and Manabe to build 3D atmosphere model, led to Geophysical Fluid Dynamics Lab.

AGCM Family Tree started for many modelling centers with shared code bases

GFDL, NCAR (National Center for Atmos. Research), ECMWF (Euro. Centre for Medium-Range Weather Forecasts), GISS (Goddard Institute for Space Sciences), UCLA, UKMO (UK Met Office)

1965 — shortfalls in models due to computational power limitations

1970s- algorithmic developments from computational fluid dyanmics (generally Aerospace)

Models had Solar Radiation, Atmosphere, Precipitation

1980s

Models included: Clouds, Land surface, prescribed ice

1990s

Models + Swamp Ocean (ocean to act as heat reservoirs)

1996s

Models + Volanism, Sulfates, Ocean currents

2001

Models + Carbon Cycle, Hydrologic cycle, deep ocean circulation, aerosols

2007

Models + Atmospheric chemistry, interactive vegetation

Steady rise in forecast skill steadily since 1955 to today, growing from 20+% to nearly 90%. 36h is lagged by 72h’s accuracy by about the same

Since early 2000s, southerm hemisphere has caught up to north

Look into: Madden Julian Oscillation (timescales up to a month), America Multi-Model Ensemble (up to 12 months in advance)

Climate simulations in US performed at NCAR Cheyenne or NERSCE (DOE) Cori Supercomputer

Fundamental mathematics required to understand the development of these models