### Lecture: August 26, 8:00-9:30 am

### Exercises: August 26, 9:40-10:30 am

## 2) Exercises

### a) Insolation and orbital theory

#### Use the

#### Exercises Orbit:

- Calculate orbital parameters!
- Calculate annual insolation at a specfic latitude!
- Plot of insolation for the last 1 million years at 65°N !
- Calculate the spectrum of the time series ! (only for
specialists)
- Calculate the space-time plot of insolation for 0 ky, 6 ky, 124 ky
BP !
- Calculate the anomaly of 6 ky and 124 ky minus today !

### b) Energy balance model and feedbacks

- What will happen if the CO2 content in the atmosphere is doubled?
Radiative forcing= 4 Wm-2
- What will happen if the factor γ is 1% higher/lower in the long-wave
radiation?
- Describe the effect if the diffusivity is enhanced by a factor of
2!
- The coalbedo of sea ice can vary between 0.3 and 0.4. Describe the
effect when varying the value!
- Write down the numerical scheme (time stepping etc. from the source
code) !
- Show the evolution at one specific latitude and discuss it!

What will happen if the CO2 content in the atmosphere is
doubled?

(Radiative forcing= 4 Wm-2= lowering of A )

Discuss the sea ice evolution during the year !

Reduce (enhance) the sea ice thermal conductivity by 20% mimiking
more (less) snow on top of sea ice !

Write down the numerical scheme (time stepping) !

#### Literature:

Berger
A., 1978 Long-term variations of daily insolation and Quaternary
climatic changes. Journal of Atmospheric Science, 35(12), 2362-2367.

Huybers, P. and I. Eisenman, 2006. Integrated summer insolation
calculations. NOAA/NCDC Paleoclimatology Program Data Contribution
#2006-079.

Lohmann,
G., 2020 Climate Dynamics: Concepts, Scaling and Multiple
Equilibria. Lecture Notes 2020, Bremen, Germany.

Lohmann,
2020 Temperatures from energy balance models: the effective heat
capacity matters, Earth Syst. Dynam., 11, 1195–1208.

Wagner
and Eisenman, 2015 How Climate Model Complexity Influences Sea Ice
Stability. Journal of Climate.