1
Supplementary information
Case sequence
Model Parameters
CCN
f
Model results
h (%)
Location
I. Simulations initiated
N
 T0
H
w
t rain
Pn
(cm-3)
(K)
(km)
(m/s)
(hr)
(kg/m2)
10 km
1
50
50
1
---
3.5
2
0
10 km
1
50
50
5
20
14
2
0.03
10 km
1
90
1
3
16
10
3
26
10 km
1
95
1
0.5
11
4.5
3.5
12
10 km
1
101
1
0
12
4
3
12
10 km
0
95
1
0.5
24
11
5
1
10 km
0
150
50
0
32
30
7
200
30 km
1
101
1
0
30
1
12
0.05
Everywhere
1
50
50
5
20
20
2
80
Everywhere
1
50
10
0.5
---
3
---
0
Everywhere
1
80
10
0.5
18
14
3.5
90
Everywhere
1
95
10
0.5
22
20
2.5
110
Everywhere
1
95
1
0
20
12
2
70
2 storms d=20 km
Everywhere
1
90
10
0.5
25
17
3.5
90
3 storms d=10 km
Everywhere
1
90
10
0.5
25
17
3.5
100
with a thermal disturbance
and CCNs at the disturbance
location.
II. Test of the role of
coagulation
III. CCN fall from the
tropopause
IV. CCN available at all
vertical levels
V. Convection initiated by
vertical updrafts (w = 1 m/s)
VI. Multiple storms
Supplement to Table 1: Additional simulations and results of Titan’s convective
clouds.
2
Supplementary figure 1: Methane molar mixing and saturation ratio profiles used
in the simulations. The maximum molar abundance of methane is fixed at 0.05 at the
surface and determines the vertical methane mixing profile for each saturation value.
Here we show the methane molar mixing ratio and saturation ratio profiles for the 50%
(purple), 80% (blue), 100% (orange), 125% (red) and 150% (green). An estimation of
the Cassini-Huygens measurements of methane relative humidity (Niemann et al. 2005)
is shown as a grey line for comparison.
3
Supplementary figure 2: Merger of two nearby convective cells simultaneously
triggered.
The time evolution of two convective cells initially separated by 20 km is shown using
the amount of cloud material as a visual tracer of the dynamics (see last cases in the
supplementary table for details of the simulation). (a) onset, (b) development to the
mature phase (c) characterized by strong precipitation and gust fronts at the surface.
Later on both storms approach until they merge (d) leaving a unique storm (e). The
panel (f) shows the accumulated rain at the final stage of the storm. Although the
average precipitation is 90 kg/m2, there are regions where precipitation can be a few
times higher (300 kg/m2).