<p>On the temperature calculation using the <sup>18</sup>O isotopes:
Calibration: The samples are always plotted against the VSMOW (Vienna Standard Mean Ocean Water) which is always 0 permil.</p>
<p>Info:
We calibrate every Sample against recent ocean water Oxygen-18. 18O concentrations in the sample similar to the ocean water have a 18O signature about 0 permil</p>
<p>The temperatures can be calculated according to the equations (in high latitudes):</p>
<p><span class="math-container">$\delta^{18}\textrm{O} = (0.521 \pm 0.014)t_a - (14.96 \pm 0.21)^0\!\!/\!_{00}$</span></p>
<p>For further information: <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation" rel="nofollow noreferrer">https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation</a></p>
<p>It is a lovely introduction to this highly interesting topic! Keep interested in this topic!</p>

CC BY-SA 4.0
2022-07-26T14:14:19.593Z
Thank you, this is very helpful! Would you have some moments to expand with a little more detail, as I am a novice in this area? Eg what does 0 permil mean? And why high latitudes?
Peter A
CC BY-SA 4.0
2022-07-27T07:51:27.060Z
Hi I hope it is more clear now!
Weiss
CC BY-SA 4.0
2022-07-27T09:28:30.173Z
Thank you very much!
Peter A
CC BY-SA 4.0
2022-07-27T09:47:11.293Z
You are welcome! If you have any outher questions to 18O, please ask! It is a highly interesting topic and a nice tool to determine earth systems (recent and palaeo)
Weiss
CC BY-SA 4.0
2022-07-26T14:06:14.443Z
2022-07-27T07:39:59.303Z
2022-07-27T07:39:59.303Z
Weiss
<p>1 Do ice core temperature reconstruction studies have a calibration step, or is the relationship between Oxygen-18 and mean global temperature considered linear enough that this is not required?</p>
<p>2 Irrespective of whether calibration is used or not, do ice core reconstruction studies supply a verification statistic (R-square) against the instrumental temperature record?</p>
<p>Please could you point me to any papers containing these statistics</p>

CC BY-SA 4.0
2022-07-21T07:25:01.543Z
This is a helpful overview of uncertainties but doesn't address the exact question https://www.ncei.noaa.gov/pub/data/paleo/icecore/ice-cores.pdf
Peter A
<paleoclimatology><isotopic>
Verification statistic for ice core temperature reconstructions
Peter A
# Verification statistic for ice core temperature reconstructions

(Asked by: username_0 on 2022-07-20)

1 Do ice core temperature reconstruction studies have a calibration step, or is the relationship between Oxygen-18 and mean global temperature considered linear enough that this is not required?

2 Irrespective of whether calibration is used or not, do ice core reconstruction studies supply a verification statistic (R-square) against the instrumental temperature record?

Please could you point me to any papers containing these statistics

**Tags:** paleoclimatology, isotopic

> **Comments:**
> **username_0**: This is a helpful overview of uncertainties but doesn't address the exact question https://www.ncei.noaa.gov/pub/data/paleo/icecore/ice-cores.pdf  

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## 1 answers

### Answer by username_1 on 2022-07-26. Score: 3 | Accepted answer

On the temperature calculation using the 18O isotopes:
Calibration: The samples are always plotted against the VSMOW (Vienna Standard Mean Ocean Water) which is always 0 permil.

Info:
We calibrate every Sample against recent ocean water Oxygen-18. 18O concentrations in the sample similar to the ocean water have a 18O signature about 0 permil

The temperatures can be calculated according to the equations (in high latitudes):

$\delta^{18}\textrm{O} = (0.521 \pm 0.014)t\_a - (14.96 \pm 0.21)^0\!\!/\!\_{00}$

For further information: <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation>

It is a lovely introduction to this highly interesting topic! Keep interested in this topic!

> **Comments:**
> **username_0**: Thank you, this is very helpful! Would you have some moments to expand with a little more detail, as I am a novice in this area? Eg what does 0 permil mean? And why high latitudes?  
> **username_1**: Hi I hope it is more clear now!  
> **username_0**: Thank you very much!  
> **username_1**: You are welcome! If you have any outher questions to 18O, please ask! It is a highly interesting topic and a nice tool to determine earth systems (recent and palaeo)  

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