buoy data 22/23fr

[Brigantine]

Interesting how very linear that density often gets. (at least for the top 200m shown) Are you able to fix the scale on that density the same way you have for temp/salinity?

[uniquorn]

Will have a go.

https://www.teos-10.org/

This site is the official source of information about the Thermodynamic Equation Of Seawater - 2010 (TEOS-10), and the way in which it should be used.

TEOS-10 is based on a Gibbs function formulation from which all thermodynamic properties of seawater (density, enthalpy, entropy sound speed, etc.) can be derived in a thermodynamically consistent manner. TEOS-10 was adopted by the Intergovernmental Oceanographic Commission at its 25th Assembly in June 2009 to replace EOS-80 as the official description of seawater and ice properties in marine science.

A significant change compared with past practice is that TEOS-10 uses Absolute Salinity SA (mass fraction of salt in seawater) as opposed to Practical Salinity SP (which is essentially a measure of the conductivity of seawater) to describe the salt content of seawater. Ocean salinities now have units of g/kg.

Absolute Salinity (g/kg) is an SI unit of concentration. The thermodynamic properties of seawater, such as density and enthalpy, are now correctly expressed as functions of Absolute Salinity rather than being functions of the conductivity of seawater. Spatial variations of the composition of seawater mean that Absolute Salinity is not simply proportional to Practical Salinity; TEOS-10 contains procedures to correct for these effects.

for ref

[uniquorn]

So, oce PlotProfile uses Tlim for temp limits and Slim for salinity. Now the axes don't jump about any more.

uses densitylim

plotProfile(ctd, xtype="density", densitylim=xlimd, ylim=ylim, type="p", col="blue")

Makes more sense. Same buoy

For comparison here is Float3901865 in the Norwegian Sea, sep2016-oct2022
Temp, salinity and density.
https://fleetmonitoring.euro-argo.eu/float/3901865

[Brigantine]

Ohh... Now that I see it like that, I think that linearity that was surprising me is just the effect of pressure. The difference between "density", and what I'm more used to looking at which is "potential density"

Interesting that they've updated the definitions. I had only seen the equations in terms of PSU before. I wonder if the new ones can even account for the exotic antarctic salt compositions that keep Don Juan Pond liquid down to -50⁰C

[uniquorn]

There might be a potential density option.

whoi top7 rawmat data.

TOP7 was deployed in open water in the Beaufort Sea on October 1, 2022 at 76° 59.4 N, 149° 16.1 W as part of the Beaufort Gyre Observing System (BGOS) during the JOIS 2022 cruise on the CCGS Louis S. St. Laurent. The TOP is operating on a standard sampling schedule of 6 two-way profiles from the surface to 200 m depth each day.

The distance between profiler top end and pressure sensor is 18 cm. I don't yet know how to correct for local pressure. Will have to look at the 4 co-located buoys. The SIMB3 records local pressure. Anyway the after effects of the oct low pressure are evident. How to interpret?

[uniquorn]

WSC incoming at roughly 8.7km/day north of Svalbard over the last 22days using worldview measurements.

https://fleetmonitoring.euro-argo.eu/float/4903641

Float 4903641
Cycle 1
Date: 03/10/2022 16:33:00 Quality: 1
Position: 80.999N 15.896E Quality: 1

Cycle 2
Date: 14/10/2022 22:58:00 Quality: 1
Position: 81.566N 20.112E Quality: 1

Cycle 3
Date: 25/10/2022 02:41:00 Quality: 1
Position: 81.573N 26.029E Quality: 1

https://go.nasa.gov/3U2I0V1

Cycle 4
Date: 04/11/2022 17:50:00 Quality: 1
Position: 81.759N 28.662E Quality: 1

Only 10 days this time. Drift dropped to 4.7km/day
nov4 location over today's ice edge on worldview. 4903641 still hugging the shelf break.
https://go.nasa.gov/3zWsyT1

We can compare with the mid july deployment of 6904221, cycle1-7

[uniquorn]

A quick look at WHOI TOP5 which is one of the 4 co-located buoys. It has some anomalies in the 1m-2m depth after deployment which also show up on whoi charts.
Was surprised to see freezing point departure(fpd) go positive recently. Looks like it's due to an increase in salinity. Maybe brine draining.

whoi top5 drift with a crop of the 1m-2m anomalies
fpd contours
temp contours
salinity

[uniquorn]

hmm. Should have looked a bit deeper. Warm eddy at 60m. That's a long way from home. iirc we did see +2.0C at 50m a couple of years ago. This is only 0.7C

maybe it was 2016
macid's mean temp at 50-60m from here

actually ties in quite well with the recent SMOS but the itp's don't get to northwind ridge this time of year.

[uniquorn]

Looking further at TOP5 with temp difference over 1m

overview, 2m-110m

close up on 2m-20m, very small difference of +-0.003C

[uniquorn]

Calibration of SIMB3 565600 temp sensors using WHOI TOP5 temps

4m temps oct17-nov11
top5 = -1.51C
565600 = -1.62C

565600 needs correction of +0.11C in ocean

[uniquorn]

simb3-448890 co-located with 2022T98 drifting from pole to Fram Strait.

At 1.4m and 1.55m thick, the ice is still cooling before bottom freeze can begin.

drift
448890 temp contours
T98 log(heat120/heat30)

[uniquorn]

It seems unlikely that 2022T97, deployed at 86.5N on aug6, will have any chance to thicken from 1.75m before reaching the Fram Strait. Ice cooling has slowed at 1.4m depth. Possibly waterlogged below that.

T97 drift
temp contours
log(heat120/heat30)

[uniquorn]

WSC incoming at roughly 8.7km/day north of Svalbard over the last 22days using worldview measurements.

https://fleetmonitoring.euro-argo.eu/float/4903641

Float 4903641
Cycle 1
Date: 03/10/2022 16:33:00 Quality: 1
Position: 80.999N 15.896E Quality: 1

Cycle 2
Date: 14/10/2022 22:58:00 Quality: 1
Position: 81.566N 20.112E Quality: 1

Cycle 3
Date: 25/10/2022 02:41:00 Quality: 1
Position: 81.573N 26.029E Quality: 1

https://go.nasa.gov/3U2I0V1

Cycle 4
Date: 04/11/2022 17:50:00 Quality: 1
Position: 81.759N 28.662E Quality: 1

Only 10 days this time. Drift dropped to 4.7km/day
nov4 location over today's ice edge on worldview. 4903641 still hugging the shelf break.
https://go.nasa.gov/3zWsyT1
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Cycle 5
Date: 14/11/2022 22:53:00 Quality: 1
Position: 81.836N 29.997E Quality: 1

drift dropped again to 2.4km/day
https://go.nasa.gov/3Gns9Ns

potential density at surface this time.

[uniquorn]

After relatively mild temperatures from nov9-16 peaking at -9C we can see it takes about 2 days for colder air temps of -32C to cool 565600 down to roughly 1m depth. Possibly another 2cm thickening on the way.
https://www.cryosphereinnovation.com/simb3/300434064565600/

very tight temp difference over 2cm of +-0.375C

[uniquorn]

Difference between absolute salinity and practical salinity for a few profiles of whoi itp136

https://dankelley.github.io/oce/reference/swAbsoluteSalinity.html

Seawater absolute salinity, in GSW formulation
Source: R/sw.R

Compute the seawater Absolute Salinity, according to the GSW/TEOS-10 formulation with gsw::gsw_SA_from_SP() in the gsw package. Typically, this is a fraction of a unit higher than practical salinity as defined in the UNESCO formulae.

example code:
#############get absolute sal and conservative temp
      abssal <- swAbsoluteSalinity(salinity, pressure.dbar., lon, lat)


absolute minus practical

[uniquorn]

Difference between Conservative temperature and in situ temperature (C)

cstemp <- swConservativeTemperature(salinity, temperature.C., pressure.dbar., lon, lat)

quite small

[uniquorn]

6903581 drifted across the Barents towards Kara, here showing aug25-nov23.
Progressive cooling till a rapid change at cycle 192.

[uniquorn]

simb3 448890 co-deployed near the pole with T98 started bottom freeze from 1.4m thick on dec11. Probably doesn't have long to thicken.

[uniquorn]

2022T98 log(heat120/heat30) giving some indication of bottom freeze or at least a phase change.

Temperature data for 2022T94-97 all stopped together on nov22, which is unusual, and they aren't visible in the active or inactive lists.

[uniquorn]

animated 2022T98 aug27-dec24 and ascat day240-357
seasons greetings to all buoy watchers

[uniquorn]

SIMB3 448890 deployed at pole on aug27 had a recent highs of -5C on jan3 and -1C on jan6.
Heat flux reversing again through the snow layer

[uniquorn]

update on 2022T98 co-located with SIMB3 448890 nearing the Fram Strait. Recent warm temperature spikes visibly slowing thickening on 448890.

log of HEAT120 divided by HEAT30 looks like a good method for estimating ice thickness, especially in winter.

[uniquorn]

As 2022T98 and SIMB3448890 drift south over the 78N line and nearer the ice edge there is an unsurprising shift in ice bottom temps and a tick up on bottom distance. Maybe related to a temporary rise in water temps. Warm eddy?

[uniquorn]

There were more

[uniquorn]

2022T98 confirming the bottom melt and also showing a significant change in state close to surface. Unfortunately this may be the last heat data we get as the last two days have been all zeros.

Closer look at 448890 from dec25. Rapid thickening then melting again. Ice warming up.

[uniquorn]

2cm temp diffs
https://www.cryosphereinnovation.com/simb3/300434064565600/

[uniquorn]

The recent low pressure event near Svalbard caused enough open water for float 6901934 to surface for the first time since nov21. It seems that only a partial profile is available.

[uniquorn]

A second argo float, 4903641, surfaced in open water north of FJL on feb14.

3.2 dbar -1.201℃ 34.243 PSU

Roughly 0.57C warmer than 10 days ago.

[uniquorn]

2022T98 confirming the bottom melt and also showing a significant change in state close to surface. Unfortunately this may be the last heat data we get as the last two days have been all zeros.

Closer look at 448890 from dec25. Rapid thickening then melting again. Ice warming up.

SIMB3 448890 also having trouble with the temperature strip since yesterday. Fairly steady bottom melt since feb6. Accelerated again due to warmer water on feb12.