Sunday, July 21, 2019

Ice Sheet Melt According To Tide Gauge Stations

Fig. 1 Tide Gauge Station Locations
In today's post we take a look at ice mass loss according to tide gauge records of measurements taken around the globe.

The graphic at Fig. 1 shows the extent of tide gauge stations.

There is also a link at Fig. 1 to a Permanent Service for Mean Sea Level (PSMSL) page which contains extensive tide gauge station information that is good enough to be used to calibrate satellite data collection instruments (NOAA, cf. Synchronizing Satellite Data With Tide Gauge Data).

The alleged problem spoken of in a recent paper (Thwaites) is fanciful for not realizing that tide gauge data covers up to two or three centuries in some cases.

Using a single glacier or a small number of them for reference is also problematic ("This result illustrates the risk of summarizing the ice sheet loss on the basis of the fate of a few glaciers." -Mouginot, Rignot et al., 2009, at 9242).
Fig. 2
Fig. 3
Fig. 4

The graphs at Fig. 2 and Fig. 3, for example, cover sea level changes with PSMSL records taken and recorded since 1809 (210 years).

The relatively new satellite record is tiny compared to the tide gauge record (Synchronizing Satellite Data With Tide Gauge Data).

With that in mind I thought I would calculate the number of gigatons of  ice melt using the hundreds of years of tide gauge records.

Before I get into how that is done, let's consider the graphs.

The graph at Fig. 2 shows the three types of sea level change (SLC).

Sea level rise (SLR), the black line on Fig. 2, is the most known to the public, sea level fall (SLF), the red line on Fig. 2, is less well known, and ghost water (green line) is virtually unknown to the public.

The graph at Fig. 4 shows the calculated ice melt (mass loss) associated with the SLR with and without including ghost water SLR.

You can see by the difference in the red line and the black line of Fig. 4 that ghost water is a necessary component of any complete SLC computation.

Let's now consider how to use the SLC record to calculate the ice mass loss.

To derive SLR (mm) from ice mass gigatons divide the gigatons value by 361.841, or to derive ice mass gigatons from an SLR value, multiply the SLR (mm) value by 361.841.

The Antarctica and Greenland tables below show the computations in the papers (Antarctic Ice Sheet, Rignot et al. 2019, Greenland Ice Sheet, Mouginot, Rignot, et al. 2019).

The tables also include my tide gauge computations so that comparisons can be made.

Remember that my calculations imply all of the Cryosphere (all locations), not just Antarctica and Greenland, so naturally the Rignot values will not match my values.

Also remember what a difference two centuries of data makes compared to four decades of data.

Here are the net comparisons between PSMSL data and the two papers:
Greenland
Rignot gt 1972 - 2018 = 5,406 (5,447 - 41)
Rignot gmsl mm 1972 - 2018 = 14.940291 (15.0536 − 0.113309)

Greenland
PSMSL gt 1972 - 2018 = 28,475.5 (57,274.1 − 28,798.6)
PSMSL gmsl mm 1972 - 2018  = 78.6654 (158.2 − 79.5346)

Antarctica
Rignot gt 1979 - 2018 = 4,450 (4,490 − 40)
Rignot gmsl mm 1979 - 2018 = 12.298254 (12.4088 −0.110546)

Antarctica
PSMSL gt 1979 - 2018 = 20,002.5 (48,210.7 − 28,208.2)
PSMSL gmsl mm 1979 - 2018 = 55.2665 (133.168 − 77.9015)


Totals (Greenland + Antarctica)

Rignot Gt: 9,856 (5,406 + 4,450)
Rignot GMSL mm: 27.238545 (14.940291 + 12.298254)

PSMSL Gt: 48,478 (28,475.5 + 20,002.5)
PSMSL GMSL mm: 133.9319 (78.6654 + 55.2665)
The countries with tide gauge stations I use (Countries With Sea Level Change - 2)  have to be added together properly, then averaged properly, in order to derive the otherwise generally useless global mean sea level (GMSL).

There are 1,512 stations of which the following 8 were excluded:
Station Number, Name

41, POTI
51, BATUMI
118, KLAIPEDA
1082, STANLEY
1597, RIMOUSKI
1796, STANLEY II
1849, KERGUELEN
2246, SAINT PIERRE ET MIQUELON

Ok, on to how the calculations are done.

It is a common error to include SLF tide gauge station records with SLR tide gauge station records when calculating GMSL.

One reason for the error is memory loss concerning applicable scientific research.

Note that the work of Woodworth 1888 and even Newton have not been used by all scientists when required.

That is, gravity has not been popular enough in sea level papers  (The Gravity of Sea Level Change, 2, 3, 4, 5) because the bathtub model is an easier sell to the public (The Bathtub Model Doesn't Hold Water, 2, 3, 4, 5).

So, where there is a net SLF I do not subtract that from the net SLR, because SLF is generally caused by the tide gauge station being near or within the hinge point of melting ice sheets (The Evolution and Migration of Sea Level Hinge Points, 2).

SLF is actually the proportional pattern of ice sheet gravity loss like CT is the proportional pattern of potential enthalpy (see e.g. Patterns: Conservative Temperature & Potential Enthalpy - 3).

I don't add the "ghost water" value ((-1.0 x SLF) x 0.27 "about a third" - Mitrovica) to the SLR value either, because it is the quantity of water moving away from the coast of the Cryosphere location to another area far away, where it will then register on tide gauges as SLR (NASA Busts The Ghost).

The next post in this series will explain why.

The Tables:

Antarctica Table

Year Rignot
Era #
Rignot
Era Year
Rignot
Era GT
Rignot
Total GT
Rignot
GMSL (mm)
PSMSL
GT
Since
1809
PSMSL
GMSL
Since
1809 (mm)
1979 1 1 40400.11054628,208.277.9015
1980 1 2 80800.22109226,706.873.7508
1981 1 3 1201200.33163729,604.281.7621
1982 1 4 1601600.44218330,288.683.6517
1983 1 5 2002000.55272936,651.2101.238
1984 1 6 2402400.66327529,848.882.4284
1985 1 7 2802800.77382128,13677.6984
1986 1 8 3203200.88436627,738.976.6076
1987 1 9 3603600.99491229,212.480.6751
1988 1 10 4004001.1054628,832.379.6298
1989 1 11 4404401.21631,115.385.9396
1990 1 12 4804801.3265529,700.282.0305
1991 2 1 505301.4647330,202.883.4122
1992 2 2 1005801.6029130,510.384.2647
1993 2 3 1506301.741129,408.581.2166
1994 2 4 2006801.8792828,969.380.0073
1995 2 5 2507302.0174630,682.784.7377
1996 2 6 3007802.1556432,415.489.5102
1997 2 7 3508302.2938333,898.493.6223
1998 2 8 4008802.4320136,663.1101.265
1999 2 9 4509302.5701935,412.797.8074
2000 2 10 5009802.7083734,671.795.7591
2001 3 1 1661,1463.1671434,504.295.2933
2002 3 2 3321,3123.625933,112.691.4528
2003 3 3 4981,4784.0846735,80998.907
2004 3 4 6641,6444.5434334,577.795.503
2005 3 5 8301,8105.002235,964.699.3383
2006 3 6 9961,9765.4609635,513.898.0888
2007 3 7 11622,1425.9197336,612.1101.132
2008 3 8 13282,3086.3784938,578.3106.562
2009 3 9 14942,4746.8372638,721.2106.941
2010 4 1 2522,7267.533742,622.8117.713
2011 4 2 5042,9788.2301340,624.1112.211
2012 4 3 7563,2308.9265742,320116.892
2013 4 4 10083,4829.6230141,995.8115.981
2014 4 5 12603,73410.319442,726.6118.004
2015 4 6 15123,98611.015941,688.7115.155
2016 4 7 17644,23811.712346,967129.731
2017 4 8 20164,49012.408848,210.7133.168

Greenland Table

Year Rignot
Era #
Rignot
Era Year
Rignot
Era GT
Rignot
Total GT
Rignot
GMSL (mm)
PSMSL
GT
Since
1809
PSMSL
GMSL
Since
1809 (mm)
1972 1 1 41410.11330928,798.679.5346
1973 1 2 82820.22661928,627.579.0667
1974 1 3 1231230.33992828,286.578.1179
1975 1 4 1641640.45323829,374.681.1319
1976 1 5 2052050.56654725,351.370.0063
1977 1 6 2462460.67985725,819.571.3001
1978 1 7 2872870.79316627,579.176.1601
1979 1 8 3283280.90647528,208.277.9015
1980 1 9 3693691.0197826,706.873.7508
1981 2 1 514201.1607329,604.281.7621
1982 2 2 1024711.3016830,288.683.6517
1983 2 3 1535221.4426236,651.2101.238
1984 2 4 2045731.5835729,848.882.4284
1985 2 5 2556241.7245128,13677.6984
1986 2 6 3066751.8654627,738.976.6076
1987 2 7 3577262.0064129,212.480.6751
1988 2 8 4087772.1473528,832.379.6298
1989 2 9 4598282.288331,115.385.9396
1990 2 10 5108792.4292429,700.282.0305
1991 3 1 419202.5425530,202.883.4122
1992 3 2 829612.6558630,510.384.2647
1993 3 3 1231,0022.7691729,408.581.2166
1994 3 4 1641,0432.8824828,969.380.0073
1995 3 5 2051,0842.9957930,682.784.7377
1996 3 6 2461,1253.109132,415.489.5102
1997 3 7 2871,1663.2224133,898.493.6223
1998 3 8 3281,2073.3357236,663.1101.265
1999 3 9 3691,2483.4490335,412.797.8074
2000 3 10 4101,2893.5623434,671.795.7591
2001 4 1 1871,4764.0791434,504.295.2933
2002 4 2 3741,6634.5959433,112.691.4528
2003 4 3 5611,8505.1127435,80998.907
2004 4 4 7482,0375.6295434,577.795.503
2005 4 5 9352,2246.1463535,964.699.3383
2006 4 6 11222,4116.6631535,513.898.0888
2007 4 7 13092,5987.1799536,612.1101.132
2008 4 8 14962,7857.6967538,578.3106.562
2009 4 9 16832,9728.2135538,721.2106.941
2010 4 10 18703,1598.7303542,622.8117.713
2011 5 1 2863,4459.5207640,624.1112.211
2012 5 2 5723,73110.311242,320116.892
2013 5 3 8584,01711.101641,995.8115.981
2014 5 4 11444,30311.89242,726.6118.004
2015 5 5 14304,58912.682441,688.7115.155
2016 5 6 17164,87513.472846,967129.731
2017 5 7 20025,16114.263248,210.7133.168
2018 5 8 22885,44715.053657,274.1158.2


That is all for today folks.

In the next post I will furnish the 1809 - 2018 Table used to produce Fig. 2 - Fig. 4 because this post is big enough already.

Review the excellent presentation in the video below, by Dr. Mitrovica, if you like.

The next post in this series is here.



3 comments:

  1. Great article, totally what I needed.

    ReplyDelete
  2. I blog frequently and I truly thank you for your content.
    This article has really peaked my interest. I am going to book mark your
    blog and keep checking for new information about once per week.
    I opted in for your RSS feed as well.

    ReplyDelete