GG 281: Atmosphere and HydrosphereAssigned: November 15 – 18
Due: November 29 – December 2
Out of 33 Marks Total
Lab 6: Snow Processes
A 50 km2 drainage basin in the Boreal region on northwestern Canada has three major cover
types, each with contrasting snow cover properties (Table 1).
Table 1: The major cover types, the percentage of the basin area that they occupy and their snow
cover properties.
Cover type
% area
ds (cm)
ρ (kg/m3)
SWE (mm) Days to melt
Conifer forest
45
85
162
Wetland
35
48
187
Lakes
20
32
195
1. A) Complete the table by providing the snow water equivalent (SWE) values for each land
cover (9 Marks).
B) What is the value of the areally-weighted SWE for the basin? Account for the variation in the
values of snow depth and of snow density presented in Table 1 (3 Marks).
C) Explain how the depth and density can change even in the absence of snowmelt and
additional snowfall (3 Marks).
2. A) Considering that the latent heat of fusion is 334 J/g, and assuming that the daily total melt
energy (QM) is 2.459 MJ/m2, fill in the last column of Table 1 with your estimate of the number
of days required to completely melt the snow (Round to nearest day) (15 Marks).
B) If a rain event occurs during the snowmelt period, explain how it could affect the rate of
snowmelt (3 Marks).
Lab 6: Snow Processes
TAs: Maude (Mo) Auclair (aucl9080@mylaurier.ca), Mikhail Mack
(mack1375@mylaurier.ca), Iain Thomson (thom6030@mylaurier.ca)
Given:
A 50 km2 drainage basin in the Boreal region on northwestern Canada has three major cover types, each with contrasting snow cover
properties (Table 1).
Table 1: The major cover types, the percentage of the basin area that they occupy and their snow cover properties.
Find:
1.
Cover type
% area
ds (cm)
ρ (kg/m3)
Conifer forest
45
85
162
Wetland
35
48
187
Lakes
20
32
195
SWE (mm)
Days to melt
A) Complete the table by providing the snow water equivalent (SWE) values for each land cover (9 Marks).
B) What is the value of the areally-weighted SWE for the basin? Account for the variation in the values of snow depth and of
snow density presented in Table 1 (3 Marks).
C) Explain how the depth and density can change even in the absence of snowmelt and additional snowfall (3 Marks).
2.
A) Considering that the latent heat of fusion is 334 J/g, and assuming that the daily total melt energy (QM) is 2.459 MJ/m2, fill in
the last column of Table 1 with your estimate of the number of days required to completely melt the snow (Round to nearest
day) (15 Marks).
B) If a rain event occurs during the snowmelt period, explain how it could affect the rate of snowmelt (3 Marks).
Total Marks: 33 Due two weeks from today: November 29 – December 2
SWE Calculation Example
Cover Type
ds (cm)
ps (kg/m3)
Meadow
54
132
𝑆𝑊𝐸 = 0.01 𝑑! 𝑝!
𝑆𝑊𝐸 = 0.01 ∗ 54 𝑐𝑚 ∗ 132
𝑆𝑊𝐸 = 71.3 𝑚𝑚
𝑘𝑔
𝑚”
SWE (mm)
Weighted Average Calculation
=
51 ∗ 10 + 86 ∗ 30 + 74 ∗ 20 + 62 ∗ 40
(10 + 30 + 20 + 40)
(7050)
=
(100)
= 70.5
Grade
Received
Weight
Quiz
51%
10%
Lab
86%
30%
Term Paper
74%
20%
Final
62%
40%
Cover Type
ds (cm)
ps (kg/m3)
SWE (mm)
Meadow
54
132
71
The daily total melt energy (QM) is 2.9 MJ/m2
Conversion of total melt energy.
Amount of melt
𝑚𝐽
𝑄# = 2.9 $
𝑚
#%
&”’ (%
= 2.9 #! ∗ ( & #% )
𝑄𝑚
𝑀=
𝑃𝑠 𝐿𝑓
𝑘𝐽
= 2900 $
𝑚
2900
=
=
𝑘𝐽
𝑚$
𝑘𝑔
𝑘𝐽
∗
333.5
𝑘𝑔
𝑚”
= 0.0658 𝑚
132
= 65.8 𝑚𝑚
Days to melt
=
)*+ (##)
“”
./012 #314 #$%
71 𝑚𝑚
65.8 𝑚𝑚
= 1.1 𝑑𝑎𝑦𝑠