Publication Date:
2018-11-12
Description:
The fluxes of sensible heat (H) and latent heat (LE), which are generally the important parts of the energy and mass balances over glacier surfaces, are widely quantified by the bulk method. However, due to the difficulty of determining the aerodynamic roughness length z 0m in this method, H and LE values may still have large uncertainties with significant inaccuracy. To acquire reliable varying and intrinsic z 0m values, new simpler parameterizations for z 0m values at different ranges of the friction velocity u *b were fitted in this study. The method was implemented using the related meteorological data and glacial sublimation/condensation measured at the top of the August-one glacier (4817 m asl) in the Qilian Mountains from 1 July 2016 to 15 August 2017. The parameterization shows that z 0m increased sharply when u *b exceeded 0.43 m/s (the approximate threshold value) and that the effect of snowdrift was slight for the hourly z 0m values in the range 0.15 ≤ u *b ≤ 0.43 m/s, which could thus be used to calculate the daily z 0m . During the wet period (1 July to 24 September 2016 and 5 May to 15 August 2017), the turbulent fluxes calculated by the bulk method showed that net radiation R net was the primary source of surface energy (60.7 w/m 2 ), whereas during the dry period (25 September 2016 to 4 May 2017), the main heat sink was the positive H (28.5 w/m 2 ) rather than the negative R net (−10.0 w/m 2 ). ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
2169-897X
Electronic ISSN:
2169-8996
Topics:
Geosciences
,
Physics
Permalink