Is the Isotope Composition of Snow a Reliable Temperature Indicator?

[Andre]

In several threads I have tried to discus the ice cores of Greenland and Antarctica about not being accurate paleo-termometers and those glacial interglacial spikes were hardly about big temperature changes but told much more about changes in precipitation patterns (caused by some pet idea).

I may have shown graphs like http://home.wanadoo.nl/bijkerk/vostok-cor2.GIF showing the extreme tight correlation between (relative) annual ice layer height and isotopes.

Of course the thermometer is the isotope composition of the precipitation which means that you can only measure temperature when it snows (or rains), a temperature, which may be far off the real average temperature especially with changing seasonalilty of precipitation. So those big spikes in the 100,000 years that show a tight correlation with precipitation may have a different message than temperature.

The beauty of being right is, that sooner or later some study will confirm it:

pp 38:

AWS data revealed that during accumulation, temperature is above average. This effect is most pronounced in winter and at low-accumulation sites such as the Antarctic plateau.

From the summary: pp 143-145

The interpretation of stable isotopes in Antarctic snow is the subject of this thesis. Isotope ratios of oxygen (d18O) and /or deuterium (dD) are widely used as proxies for atmospheric temperature, on a variety of time scales. A significant spatial correlation between mean annual surface temperature (Ts) and the average isotopic composition of snow (d) is commonly used as argument to use d values a a paleothermometer. However, previous research has shown that this spatial d - Ts relation is also influenced by other processes, and is not always constant over time. This obscures the interpretation of isotope records, and points out that isotope records from ice cores should not be quantitatively translated to temperature changes without calibration, using independent temperature records.

 

[Mk]

How do you pronounce d180 and dD?

 

[ravenprp]

Based on the above content, it is clear that the isotope composition of snow is not a reliable temperature indicator. While there may be a correlation between isotope ratios and temperature, it is not a direct and consistent relationship. Other factors, such as precipitation patterns, can also influence the isotope composition of snow and therefore affect its reliability as a temperature indicator.

Furthermore, this content suggests that isotope records from ice cores should not be solely relied upon to determine temperature changes. Instead, these records should be calibrated using independent temperature records in order to accurately interpret the data.

It is important to consider all factors and variables when studying past climate changes, and not to rely solely on one indicator. This content highlights the need for continued research and calibration in order to fully understand the complexities of past climate changes.