Table 1 Mean values of meteorological and radiation parameters on the glacier for the period 7 July to 23 August.

Air temperature, T (°C)

7.3

6.8

− 1.0

Relative humidity, RH (%)

76.0

80.6

9.1

Precipitation, P (mm)

119.4

195.7

152.6

Specific humidity, q (g kg⁻¹)

6.4

6.7

0.5

Atmospheric pressure, p (hPa)

749.1

748.6

− 1.0

Wind speed, u (m s⁻¹)

1.1

1.2

0.2

Maximal wind speed, u_m (m s⁻¹)

3.5

3.8

0.5

Wind direction (°)

–

–

–

Incoming shortwave radiation, S_in (W m⁻²)

157.8

141.6

− 32.5

Reflected shortwave radiation, S_ref (W m⁻²)

67.8

63.1

− 9.5

Incoming longwave radiation, L_in (W m⁻²)

300.6

309.9

18.6

Outgoing longwave radiation, L_out (W m⁻²)

315.6

315.6

0.0

Sensible heat, H (W m⁻²)

2.1

3.2

2.1

Latent heat, LE (W m⁻²)

1.3

2.2

1.8

Atmospheric transmissivity, τ

0.37

0.34

− 0.06

Albedo (accumulative), α_acc

0.43

0.45

0.04

Total cloudiness, C_tot (%)

67.5

73.2

11.3

Low cloudiness, C_low (%)

44.4

51.3

13.7