|
ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2023):
PLEASE see important notes about this, below...
Glacier-specific Scaling Parameter, c:
0.022042
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| Volume, mi3 |
0.1526 |
0.0984 |
0.0700 |
0.0677 |
0.0544 |
0.0535 |
0.0502 |
| Volume, km3 |
0.6363 |
0.4102 |
0.2918 |
0.2821 |
0.2268 |
0.2231 |
0.2091 |
Volume Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -0.054 mi3
(-0.226 km3) | -0.083 mi3
(-0.344 km3) | -0.085 mi3
(-0.354 km3) | -0.098 mi3
(-0.410 km3) | -0.099 mi3
(-0.413 km3) | -0.102 mi3
(-0.427 km3) |
|---|
| 1913 | -- | -0.028 mi3
(-0.118 km3) | -0.031 mi3
(-0.128 km3) | -0.044 mi3
(-0.183 km3) | -0.045 mi3
(-0.187 km3) | -0.048 mi3
(-0.201 km3) |
|---|
| 1971 | | -- | -0.002 mi3
(-0.010 km3) | -0.016 mi3
(-0.065 km3) | -0.016 mi3
(-0.069 km3) | -0.020 mi3
(-0.083 km3) |
|---|
| 1994 | | | -- | -0.013 mi3
(-0.055 km3) | -0.014 mi3
(-0.059 km3) | -0.018 mi3
(-0.073 km3) |
|---|
| 2009 | | | | -- | -0.001 mi3
(-0.004 km3) | -0.004 mi3
(-0.018 km3) |
|---|
| 2015 | | | | | -- | -0.003 mi3
(-0.014 km3) |
|---|
Percent Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -35.53% | -54.14% | -55.67% | -64.36% | -64.94% | -67.13% |
|---|
| 1913 | -- | -28.87% | -31.23% | -44.72% | -45.62% | -49.02% |
|---|
| 1971 | | -- | -3.32% | -22.28% | -23.55% | -28.33% |
|---|
| 1994 | | | -- | -19.61% | -20.92% | -25.87% |
|---|
| 2009 | | | | -- | -1.63% | -7.78% |
|---|
| 2015 | | | | | -- | -6.25% |
|---|
Important comments about the calculation of volume shown here
The calculation of glacial volume shown on this page is based on an analysis of two methods used at Mount Rainier in the past (Driedger and Kennard [1986]; and Nylen [2001]) as well as the most recent literature review for glacier area-volume scaling (Please review Beason et al. [2023] for an in-depth discussion about this issue). It should be noted that simply converting area to volume with an equation is extremely difficult and the values presented here have extremely large error margins (likely ± 35% or more). With that in mind, the values presented here should give you an estimate of the glacial volume and change in volume over time. Please use these data very carefully with those caveats.
The calcuation of the volume is as follows:
\[V_i = {(c_iA_i^{1.375}) + (c_nA_i^{1.36}) \over 2}\]
Where:
\(V_i\) = Average volume for the glacier in question (km3);
\(c_i\) = The glacier-specific scaling parameter (back-calculated from glacier area and volume in 1971 in Driedger and Kennard (1986); Method described in Beason et al. (2023). The value for the North Mowich Glacier is 0.022042 (this is also listed above the volume graph);
\(c_n\) = The back-calculated scaling parameter from Nylen (2001) of 0.0255; and
\(A_i\) = The measured volume of the glacier in question (km2).
This is essentially an average of the back-calculated Dreidger and Kennard (1986) and Nylen (2001) methods (D&K is in the first parenthesis; Nylen in the second). For example, for the North Mowich Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0471 mi3 (0.1964 km3).
Back-calculated Nylen (2001) Method: 0.0532 mi3 (0.2218 km3).
Average of the two (above equation and values listed for 2021 here): 0.0502 mi3 (0.2091 km3).
Official volume estimate listed above, with error: 0.0502 ± 0.0176 mi3 (0.2091 ± 0.0732 km3).
As you can see, the D&K method tends to produce higher values and Nylen produces lower values; the average of these two methods probably estimates the glacial volume. Until further research is done in this area and we can develop a better method or equation to determine volumes, this is the method we are using to determine glacial volumes. For more information about this method, please read the methods section of Beason et al. (2023).
|