Table 1 Simulation scenarios and statistics

From: Dissecting cirrus clouds: navigating effects of turbulence on homogeneous ice formation

 

ε m2 s−3

D m2 s−1

ν s−1

ni # g−1

nsed # g−1

ri μm

qi ppm

qv ppm

Trad

—

—

—

167.9 ± 9.3

0

20.7 ± 0.1

5.7 ± 0.2

102.0 ± 0.2

NoSed

—

—

—

290.2 ± 31.4

0

14.2 ± 0.4

3.4 ± 0.2

104.3 ± 0.2

NoTurb

—

—

—

286.7 ± 39.9

58

14.3 ± 0.3

3.4 ± 0.5

104.3 ± 0.03

Base

10−5

0.015

3

295.2 ± 88.8

49

14.0 ± 0.9

3.4 ± 1

104.4 ± 0.7

Turb-low

10−6

0.0015

0.3

289.5 ± 60.4

55

14.2 ± 0.5

3.4 ± 0.7

104.3 ± 0.4

Turb-high

10−4

0.15

30

289 ± 72.9

28

13.6 ± 0.9

3 ± 0.7

104.8 ± 0.6

Anvil

10−5

0.015

3

613.3 ± 204.5

47

8.8 ± 0.6

1.75 ± 0.6

42.5 ± 0.4

TTL

10−5

0.015

3

8474 ± 3415

28

1.45 ± 0.15

0.12 ± 0.04

3.1 ± 0.04

  1. Given the dissipation rate of turbulence kinetic energy (ε), turbulent diffusivity (D) and average rate of turbulent mixing events (ν) are inferred model variables. Results (mean ± standard deviation), sampled from vertical profiles of all statistical realisations, include nucleated ICNCs (ni), their mean radii (ri) and ice water mass mixing ratio (qi), and H2O mass mixing ratio (qv). Moreover, nsed denotes the mean number concentration of ice crystals that settled out of the freezing layer during HFEs. Relative to the baseline scenario Base, sensitivity scenarios NoTurb, NoSed, and Trad allows us to assess the role of physical processes and to compare with traditional simulations, respectively. Scenarios Turb vary turbulence intensity. Scenarios Anvil and TTL evaluate effects of lower air temperature and pressure. Simulations are based on initially uniform vertical profiles of temperature of 220 K and pressure of 230 hPa and qv = 107.7 ppm (Anvil: 210 K, 150 hPa, 44.25 ppm; TTL: 190 K, 100 hPa, 3.18 ppm). All scenarios assume a mean updraught speed of 0.1 m/s, a Brunt-Väisälä frequency of 0.015 s−1, and an inner (outer) length scale of turbulence of 0.1 m (15 m).
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