Tuesday

1. If a parent domain has a grid spacing of 12 km, a possible value for the grid spacing of one of its nests is:

Any value less than 12 km

4 km

5 km

None of the above

Grid spacing for child domains is determined by the value given to the parent_grid_ratio. This number must be an integer, and therefore the only value above that would work for a parent domain with grid spacing of 10, would be 4 km. This would mean that parent_grid_ratio was set to 3.

Explanation

Grid spacing for child domains is determined by the value given to the parent_grid_ratio. This number must be an integer, and therefore the only value above that would work for a parent domain with grid spacing of 10, would be 4 km. This would mean that parent_grid_ratio was set to 3.

2. It is possible to have more than one nested domain, with all sharing the same parent.

True

False

Multiple child nests do not have to be embedded in each other. It is possible to have several side-by-side within a parent domain.

Explanation

Multiple child nests do not have to be embedded in each other. It is possible to have several side-by-side within a parent domain.

3. The terms "one way" and "two way" nesting refer to:

The total number of nests in a domain

The number of input domains for WRF (coarse-grid only, or an input file for each domain)

Whether the fine-grid domain is feeding information back to the parent domain

Smoothing options

4. How does the model determine the nest domain's time step?

Through the namelist option 'parent_grid_ratio'

Through the namelist option 'parent_time_step_ratio'

The nest domain uses the same time step as the parent domain

5. What is the suggested appropriate integer ratio for a nest domain to use for a real-data application?

Any odd number

Any even number

Odd number less than 7

Odd numbered nest ratios make feedback more accurate (because of the coincident grids). When the nest ratio is too large, it could make model solutions jump too much between the domains.

Explanation

Odd numbered nest ratios make feedback more accurate (because of the coincident grids). When the nest ratio is too large, it could make model solutions jump too much between the domains.

6. Which of these is NOT calculated by a land surface model?

Heat flux

Moisture flux

Friction effect

Soil-layer temperatures

Snow cover

An LSM only computes heat and moisture fluxes, not momentum flux, which is related to frictional effects.

Explanation

An LSM only computes heat and moisture fluxes, not momentum flux, which is related to frictional effects.

7. Above which model top level does ozone become an important factor to consider in your radiation scheme?

100 hPa

50 hPa

10 hPa

Ozone becomes important for model tops above 20km or 50 hPa.

Explanation

Ozone becomes important for model tops above 20km or 50 hPa.

8. Which one of these grid sizes would be better for LES schemes than PBL schemes?

100 m

1 km

10 km

LES is suitable for grid sizes up to about 100 m.

Explanation

LES is suitable for grid sizes up to about 100 m.

9. Regarding running long simulations for regional climate, which of these is a FALSE statement?

You need to use sst_update to have a time-varying sea-surface temperature and sea ice cover

You do not need to use sst_update to have a time-varying vegetation fraction

You need to use an LSM that has evolving soil moisture and snow cover

You need a wrflowinp file

Since most of the LSM's do not have a dynamic vegetation (----), the model needs to include vegetation cover from the wrlowinp file so that fluxes from LSM's can be computed.

Explanation

Since most of the LSM's do not have a dynamic vegetation (----), the model needs to include vegetation cover from the wrlowinp file so that fluxes from LSM's can be computed.