A wind proxy based on migrating dunes at the Baltic coast: statistical analysis of the link between wind conditions and sand movement
We statistically analyse the relationship between the structure of migrating dunes in the southern Baltic and the driving wind conditions over the past 26 years, with the long-term aim of using migrating dunes as a proxy for past wind conditions at an interannual resolution. <br> <br&...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
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| Series: | Earth System Dynamics |
| Online Access: | https://www.earth-syst-dynam.net/8/639/2017/esd-8-639-2017.pdf |
| Summary: | We statistically analyse
the relationship between the structure of migrating dunes in the southern
Baltic and the driving wind conditions over the past 26 years, with the
long-term aim of using migrating dunes as a proxy for past wind conditions at
an interannual resolution.
<br>
<br>
The present analysis is based on the dune record derived from geo-radar
measurements by Ludwig et al. (2017). The dune system is located at the Baltic
Sea coast of Poland and is migrating from west to east along the coast. The
dunes present layers with different thicknesses that can be assigned to
absolute dates at interannual timescales and put in
relation to seasonal wind conditions. To statistically analyse this record
and calibrate it as a wind proxy, we used a gridded regional meteorological
reanalysis data set (coastDat2) covering recent decades. The
identified link between the dune annual layers and wind conditions was
additionally supported by the co-variability between dune layers and observed
sea level variations in the southern Baltic Sea.
<br>
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We include precipitation and temperature into our analysis, in addition to
wind, to learn more about the dependency between these three atmospheric
factors and their common influence on the dune system. We set up a
statistical linear model based on the correlation between the frequency of
days with specific wind conditions in a given season and dune migration
velocities derived for that season. To some extent, the dune records can be
seen as analogous to tree-ring width records, and hence we use a
proxy validation method usually applied in dendrochronology,
cross-validation with the leave-one-out method, when the observational record
is short. The revealed correlations between the wind record from the
reanalysis and the wind record derived from the dune structure is in the
range between 0.28 and 0.63, yielding similar statistical validation skill as
dendroclimatological records. |
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| ISSN: | 2190-4979 2190-4987 |