Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Statistical models for use of palaeosol magnetic properties as proxies of palaeorainfall
AU - Maher, Barbara
AU - Possolo, A.
PY - 2013/12
Y1 - 2013/12
N2 - The magnetic properties of well-drained, near-neutral modern soils exhibit strong relationships with mean annual precipitation (MAP, conventional 30-year averages). The pedogenic magnetic susceptibility is low for low MAP values (≈300mm/yr), increases with increasing MAP (up to ≈1500mm/yr), and then flattens or declines for higher MAP values. These relationships have been amply documented, characterised quantitatively, and used for Quaternary palaeorainfall reconstructions. However, neither the fitting of climofunctions nor the evaluationof the associated uncertainty had yet been done recognizing the measurement errors that invariably affect the values of magnetic susceptibility and of MAP. Using published datasets – from the Great Plains of the United States, from the Chinese Loess Plateau and the Russian steppe, from arid and tropical areas of Mali, and from Mediterranean and Saharan regions of Morocco – we illustrate the development and calibration of statistical models that enable the use of magnetic properties of palaeosols as proxies for palaeorainfall. The methods we use (errors-in-variables regression) take into account the measurement errors that inevitably affect both the measurements of magnetic susceptibility, and of rainfall. We also characterise the uncertainty of the palaeoclimatic reconstructions that these models produce, and show that the uncertainty with which we can estimatethe long-term (over hundreds of years) average values of MAP that truly characterise the prevailing climate, is sufficiently small to enable reliable palaeoclimate reconstructions. As an example, we provide an assessment of the uncertainty of the Holocene palaeorainfall reconstruction for Duowa, Qinghai Province, in the Chinese Loess Plateau, which corroborates the changes in the regimen of monsoons detected in previous studies.
AB - The magnetic properties of well-drained, near-neutral modern soils exhibit strong relationships with mean annual precipitation (MAP, conventional 30-year averages). The pedogenic magnetic susceptibility is low for low MAP values (≈300mm/yr), increases with increasing MAP (up to ≈1500mm/yr), and then flattens or declines for higher MAP values. These relationships have been amply documented, characterised quantitatively, and used for Quaternary palaeorainfall reconstructions. However, neither the fitting of climofunctions nor the evaluationof the associated uncertainty had yet been done recognizing the measurement errors that invariably affect the values of magnetic susceptibility and of MAP. Using published datasets – from the Great Plains of the United States, from the Chinese Loess Plateau and the Russian steppe, from arid and tropical areas of Mali, and from Mediterranean and Saharan regions of Morocco – we illustrate the development and calibration of statistical models that enable the use of magnetic properties of palaeosols as proxies for palaeorainfall. The methods we use (errors-in-variables regression) take into account the measurement errors that inevitably affect both the measurements of magnetic susceptibility, and of rainfall. We also characterise the uncertainty of the palaeoclimatic reconstructions that these models produce, and show that the uncertainty with which we can estimatethe long-term (over hundreds of years) average values of MAP that truly characterise the prevailing climate, is sufficiently small to enable reliable palaeoclimate reconstructions. As an example, we provide an assessment of the uncertainty of the Holocene palaeorainfall reconstruction for Duowa, Qinghai Province, in the Chinese Loess Plateau, which corroborates the changes in the regimen of monsoons detected in previous studies.
KW - Palaeoclimate
KW - Palaeorainfall
KW - Magnetic susceptibility
KW - Pedogenesis
KW - Palaeosol
KW - Climofunction
KW - Logistic curve
KW - Errors-in-variables
KW - Bootstrap
KW - Simultaneous confidence region
U2 - 10.1016/j.gloplacha.2013.09.017
DO - 10.1016/j.gloplacha.2013.09.017
M3 - Journal article
VL - 111
SP - 280
EP - 287
JO - Global and Planetary Change
JF - Global and Planetary Change
ER -