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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:
0.031247
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| Volume, mi3 |
0.0777 |
0.0367 |
0.0295 |
0.0204 |
0.0201 |
0.0176 |
0.0169 |
| Volume, km3 |
0.3238 |
0.1531 |
0.1230 |
0.0852 |
0.0838 |
0.0733 |
0.0706 |
Volume Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -0.041 mi3
(-0.171 km3) | -0.048 mi3
(-0.201 km3) | -0.057 mi3
(-0.239 km3) | -0.058 mi3
(-0.240 km3) | -0.060 mi3
(-0.250 km3) | -0.061 mi3
(-0.253 km3) |
|---|
| 1913 | -- | -0.007 mi3
(-0.030 km3) | -0.016 mi3
(-0.068 km3) | -0.017 mi3
(-0.069 km3) | -0.019 mi3
(-0.080 km3) | -0.020 mi3
(-0.082 km3) |
|---|
| 1971 | | -- | -0.009 mi3
(-0.038 km3) | -0.009 mi3
(-0.039 km3) | -0.012 mi3
(-0.050 km3) | -0.013 mi3
(-0.052 km3) |
|---|
| 1994 | | | -- | 0.000 mi3
(-0.001 km3) | -0.003 mi3
(-0.012 km3) | -0.003 mi3
(-0.015 km3) |
|---|
| 2009 | | | | -- | -0.003 mi3
(-0.010 km3) | -0.003 mi3
(-0.013 km3) |
|---|
| 2015 | | | | | -- | -0.001 mi3
(-0.003 km3) |
|---|
Percent Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | -52.73% | -62.01% | -73.70% | -74.13% | -77.35% | -78.20% |
|---|
| 1913 | -- | -19.62% | -44.37% | -45.27% | -52.09% | -53.87% |
|---|
| 1971 | | -- | -30.79% | -31.92% | -40.39% | -42.61% |
|---|
| 1994 | | | -- | -1.63% | -13.87% | -17.08% |
|---|
| 2009 | | | | -- | -12.45% | -15.71% |
|---|
| 2015 | | | | | -- | -3.73% |
|---|
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 Tahoma Glacier is 0.031247 (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 Tahoma Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0187 mi3 (0.0781 km3).
Back-calculated Nylen (2001) Method: 0.0151 mi3 (0.0631 km3).
Average of the two (above equation and values listed for 2021 here): 0.0169 mi3 (0.0706 km3).
Official volume estimate listed above, with error: 0.0169 ± 0.0059 mi3 (0.0706 ± 0.0247 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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