1. explore • inspire • engage

2. Overview Some slides about resolution
Short video: build a climate model
Hands-on activity: resolution vs. computing time
A few more slides: why we need supercomputers

3. Resolution: What Does It Mean?

4. Improving Resolution of Climate Models
Grid Cell Sizes
1990s (T42)
200 x 300 km
120 x 180 miles
2000s (T85)
100 x 150 km
60 x 90 miles
Resolution – temporal and spatial – relationship to computing power or resources needed – differences in Wx vs. Climate models
Credit: Warren Washington, NCAR

5. Improving Resolution of Climate Models
Around the time of the First Assessment Report (FAR) in 1990, many climate models used a grid with cells of about 500 km (311 miles) on a side (upper left image). By the time of the the Second Assessment Report (SAR) in 1996, resolution had improved by a factor of two, producing grid cells 250 km (155 miles) on a side. Models references in the Third Assessment Report (TAR) in 2001 generally had reduced grid cells sizes to about 180 km (112 miles), while Fourth Assessment Report (AR4) models typically used a 110 km (68 mile) wide grid cell, further improving resolution.
Notice how elements of topography, such as the Alps Mountains, are shown in much greater detail in higher-resolution models. This allows such models to begin to make reasonable forecasts of regional climate in the future, a currently emerging capability.
Credit: Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4): Working Group 1: Chapter 1, page 113, Fig. 1.4

6. Vertical Resolution of Climate Models
Vertical Layers
1990s
10 layer atmosphere
1 layer “slab” ocean
2000s
30 layer atmosphere
30 layer ocean
Credit: UCAR

7. Horizontal and Vertical Grid

8. Horizontal and Vertical Grid

9. Building a Climate Model Movie
gcm_model_grid_very_hi_res.mov

10. One-dimensional Model
40 km resolution
each square on checkerboard represents 10 km
cards are every fourth square
4 x 10 km = 40 km

11. One Dimensional Data - Altitude

12. One-dimensional Model
40 km resolution
2 calculations

13. One-dimensional Model
20 km resolution
4 calculations

14. One-dimensional Model
10 km resolution
8 calculations

15. 80 km x 80 km square – how big?

16. Two-dimensional Model
40 km resolution
4 calculations

17. Two-dimensional Model
20 km resolution
16 calculations

18. Two-dimensional Model
10 km resolution
64 calculations

19. Two-dimensional Model
10 km resolution
64 calculations

20. Resolution and Computing Power
Double resolution – increase number of nodes – more calculations!
One Dimension
2 times as many nodes
relationship between resolution and computing power or resources needed
show simple math of need for 16x computing power if temporal and spatial (x, y and z) resolution double
supercomputing – movies at end
Two Dimensions
4 times as many nodes

21. Three Dimensions

22. Fourth Dimension – Time!

23. Double Resolution – in 4 Dimensions
What happens to number of calculations if we double the resolution in four dimensions (3 space + time)?
relationship between resolution and computing power or resources needed
show simple math of need for 16x computing power if temporal and spatial (x, y and z) resolution double
supercomputing – movies at end

24. Double Resolution – in 4 Dimensions
16 times as many nodes – 16x computing power required!
This is why we need supercomputers!

25. Activity Data and Graph

26. Extras?
Extra

27. TitleTitle
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28. Hexagonal Grid and Sub-grids
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Grids – hexagonal vs. rectangular
Credit: UCAR (Lisa Gardiner)

29. TitleTitle
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30. Evolution of Climate Models
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Credit: Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4): Working Group 1: Chapter 1, page 99, Fig. 1.2