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ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2023):
PLEASE see important notes about this, below...
Glacier-specific Scaling Parameter, c:
0.02217
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| Volume, mi3 |
0.0563 |
0.0474 |
0.0392 |
0.0388 |
0.0376 |
0.0350 |
0.0333 |
| Volume, km3 |
0.2348 |
0.1977 |
0.1635 |
0.1619 |
0.1566 |
0.1460 |
0.1387 |
Volume Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -0.009 mi3
(-0.037 km3) | -0.017 mi3
(-0.071 km3) | -0.018 mi3
(-0.073 km3) | -0.019 mi3
(-0.078 km3) | -0.021 mi3
(-0.089 km3) | -0.023 mi3
(-0.096 km3) |
|---|
| 1913 | -- | -0.008 mi3
(-0.034 km3) | -0.009 mi3
(-0.036 km3) | -0.010 mi3
(-0.041 km3) | -0.012 mi3
(-0.052 km3) | -0.014 mi3
(-0.059 km3) |
|---|
| 1971 | | -- | 0.000 mi3
(-0.002 km3) | -0.002 mi3
(-0.007 km3) | -0.004 mi3
(-0.018 km3) | -0.006 mi3
(-0.025 km3) |
|---|
| 1994 | | | -- | -0.001 mi3
(-0.005 km3) | -0.004 mi3
(-0.016 km3) | -0.006 mi3
(-0.023 km3) |
|---|
| 2009 | | | | -- | -0.003 mi3
(-0.011 km3) | -0.004 mi3
(-0.018 km3) |
|---|
| 2015 | | | | | -- | -0.002 mi3
(-0.007 km3) |
|---|
Percent Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -15.82% | -30.37% | -31.07% | -33.33% | -37.82% | -40.95% |
|---|
| 1913 | -- | -17.28% | -18.12% | -20.80% | -26.14% | -29.85% |
|---|
| 1971 | | -- | -1.01% | -4.25% | -10.71% | -15.19% |
|---|
| 1994 | | | -- | -3.28% | -9.80% | -14.33% |
|---|
| 2009 | | | | -- | -6.74% | -11.42% |
|---|
| 2015 | | | | | -- | -5.02% |
|---|
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 South Mowich Glacier is 0.02217 (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 South Mowich Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0313 mi3 (0.1303 km3).
Back-calculated Nylen (2001) Method: 0.0353 mi3 (0.1470 km3).
Average of the two (above equation and values listed for 2021 here): 0.0333 mi3 (0.1387 km3).
Official volume estimate listed above, with error: 0.0333 ± 0.0116 mi3 (0.1387 ± 0.0485 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).
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