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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:
0.031341
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| Volume, mi3 |
0.1236 |
0.1557 |
0.1101 |
0.1113 |
0.0986 |
0.0453 |
0.0406 |
| Volume, km3 |
0.5151 |
0.6490 |
0.4591 |
0.4639 |
0.4112 |
0.1888 |
0.1693 |
Volume Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | 0.032 mi3
(0.134 km3) | -0.013 mi3
(-0.056 km3) | -0.012 mi3
(-0.051 km3) | -0.025 mi3
(-0.104 km3) | -0.078 mi3
(-0.326 km3) | -0.083 mi3
(-0.346 km3) |
|---|
| 1913 | -- | -0.046 mi3
(-0.190 km3) | -0.044 mi3
(-0.185 km3) | -0.057 mi3
(-0.238 km3) | -0.110 mi3
(-0.460 km3) | -0.115 mi3
(-0.480 km3) |
|---|
| 1971 | | -- | 0.001 mi3
(0.005 km3) | -0.012 mi3
(-0.048 km3) | -0.065 mi3
(-0.270 km3) | -0.070 mi3
(-0.290 km3) |
|---|
| 1994 | | | -- | -0.013 mi3
(-0.053 km3) | -0.066 mi3
(-0.275 km3) | -0.071 mi3
(-0.295 km3) |
|---|
| 2009 | | | | -- | -0.053 mi3
(-0.222 km3) | -0.058 mi3
(-0.242 km3) |
|---|
| 2015 | | | | | -- | -0.005 mi3
(-0.020 km3) |
|---|
Percent Change Between Periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 | 25.99% | -10.87% | -9.95% | -20.18% | -63.35% | -67.14% |
|---|
| 1913 | -- | -29.26% | -28.53% | -36.65% | -70.91% | -73.92% |
|---|
| 1971 | | -- | 1.03% | -10.45% | -58.88% | -63.13% |
|---|
| 1994 | | | -- | -11.36% | -59.30% | -63.50% |
|---|
| 2009 | | | | -- | -54.08% | -58.83% |
|---|
| 2015 | | | | | -- | -10.33% |
|---|
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 Cowlitz Glacier is 0.031341 (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 Cowlitz Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0452 mi3 (0.1883 km3).
Back-calculated Nylen (2001) Method: 0.0360 mi3 (0.1503 km3).
Average of the two (above equation and values listed for 2021 here): 0.0406 mi3 (0.1693 km3).
Official volume estimate listed above, with error: 0.0406 ± 0.0142 mi3 (0.1693 ± 0.0593 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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