Did you know that it’s not only the oceans that have a tide? Yes, the solid Earth has tides as well, and they are not so small as one might imagine.
This example shows a global view of the vertical component of the Earth tide for a perticular data.
using GMT
GMT.resetGMT() # hide
G = earthtide(T="2022-07-07T12:00:00");
imshow(G, coast=true, colorbar=true, title="Earth tide at noon 7-July-2022")Precompiling packages... 62761.4 ms ✓ GMT 1 dependency successfully precompiled in 68 seconds. 80 already precompiled. [ Info: Precompiling GMTParkerFFTExt [35a23bc9-6f20-5cbc-8971-9cdf66427582]
Now we show the three components of the Earth tide for a specific location (the Panama Cannal) and time interval (the 7’th July 2022).
First we compute the components that will come out in a with named columns. This is handy because we can refer to them by name instead of by column number.
D = earthtide(range=("2022-07-07T", "2022-07-08T", "1m"), location=(-82,9))
1441×4 GMTdataset{Float64, 2}
Row │ Time East North Vertical
─────┼────────────────────────────────────────────────────────
1 │ 2022-07-07T00:00:00 -0.0186548 -0.0120856 0.152718
2 │ 2022-07-07T00:01:00 -0.0187063 -0.0123039 0.152364
3 │ 2022-07-07T00:02:00 -0.0187575 -0.0125214 0.152003
4 │ 2022-07-07T00:03:00 -0.0188083 -0.0127382 0.151636
5 │ 2022-07-07T00:04:00 -0.0188586 -0.0129542 0.151263
6 │ 2022-07-07T00:05:00 -0.0189085 -0.0131695 0.150883
7 │ 2022-07-07T00:06:00 -0.018958 -0.0133839 0.150496
8 │ 2022-07-07T00:07:00 -0.0190071 -0.0135975 0.150103
9 │ 2022-07-07T00:08:00 -0.0190558 -0.0138102 0.149704
10 │ 2022-07-07T00:09:00 -0.0191041 -0.0140221 0.149298
11 │ 2022-07-07T00:10:00 -0.0191519 -0.0142331 0.148886
12 │ 2022-07-07T00:11:00 -0.0191993 -0.0144432 0.148468
13 │ 2022-07-07T00:12:00 -0.0192463 -0.0146525 0.148044
⋮ │ ⋮ ⋮ ⋮ ⋮Now plot the three of them with a legend
D = earthtide(range="2022-07-07T/2022-07-08T/1m", location=(-82,9)); # hide
plot(D[:Time, :Vertical], lc=:red, lw=1, legend=:Vertical,
title="Earth tide components (m) at Panama Cannal")
plot!(D[:Time, :East], lc=:green, lw=1, legend=:East)
plot!(D[:Time, :North], lc=:blue, lw=1, legend=:North, show=true)
And now, let’s see a full month of tidal data (vertical component).
D = earthtide(range=("2022-07-01T", "2022-07-31T", "1m"), location=(-82,9));
plot(D[:Time, :Vertical], lc=:blue, legend=:Vertical, title="Tides (m), one month", show=true)