OCR Text |
Show - 14 - Locat ion W1 joch Alta h = 3- 8 cm Alta h = 8- 13 cm Berthoud Pass t- 1 i .- , pa mb 730 735 735 670 Mean d cm 0.5 0.1 0.15 0.35 Mean Tc ° C - 5.0 - 3.9 - 6.3 - 8.2 Mean dT/ dz ° C/ cm 0.7 0.46 0.54 0.32 initial g/ cnr 0.19 0.31 0.31 0.17 final . g/ cnK 0.22 0.31 0.32 0.34 | titie t ( days) actual 40 12 12 55 calculated by'eq. ( 20) 29 8 13 56 corrected 23 9 15 68 The last column of corrected time in days is obtained by replacing the assumed density of 0,28 g/ cm in equation ( 20) with the actual value for the final density of the depth hoar formed, which is available from each of these experiments. Considering the wide range of altitude, climate, experimental conditions and initial snow types which these experiments encompass, the agreement between theory and observation is remarkably good. Equation ( 20,) which has been derived purely from theoretical considerations of water vapor diffusion and generalized geometry of snow cover structure, appears in fact to describe the influence of various climatic factors accurately. Further checks against observation no doubt will suggest some refinements, but the validity of the approach appears to be established. |