Regional Precipitation Trends Since 1500 Ce, Reconstructed from Calcite Sublayers of a Varved Mediterranean Lake Record (Central Pyrenees)

Abstract

The Mediterranean is one of the regions of the world where human-induced climate warming is expected to have large impacts on water and environmental resources. To predict shifts in the current climate system, more regional climate records, including seasonal-to-century scale variability spanning longer than the instrumental periods, are needed. To help fill this gap, we provide a reconstruction of autumn precipitation variations for the Central Pyrenees range since 1500 Common Era (CE) using the varved sediments of Lake Montcortès. To assess the suitability of the calcite sublayer width of the sediments of this lake as a proxy for precipitation anomalies, we performed an analysis and smoothing of the temporal structure of the width series, calibration of the new series with the available instrumental climate records, calculation of a transfer function and testing and comparison of the reconstructed series against available empirical data.The prediction model was statistically robust and showed that the climatic signal was captured in the calcite sublayers. The reconstruction provides the first estimations of regional autumn precipitation shifts in the Central Pyrenees at annual resolution, since 1500 CE. Pronounced interdecadal shifts in precipitation were noticeable; no increasing nor decreasing linear trends or periods of extreme precipitation events were identified. The reconstructed precipitation anomalies suggest a decrease in rainfall during the coldest phase within the coldest period of the Little Ice Age and also during the 20th century, probably associated to current Global Warming. Correlations between autumn precipitation and the North Atlantic Oscillation, Western Mediterranean Oscillation and Southern Oscillation indices were weak to moderate. A potential relationship with the Atlantic Multidecadal Oscillation pattern is suggested. The reconstructed autumn precipitation trends are coherent with other palaeohydrological reconstructions in similar Mediterranean settings, and consistent at a regional level.

Resilience of Pyrenean Forests After Recurrent Historical Deforestations

“…Therefore, in addition to increasing resolution and adopting a genuine ecological approach, the use of proxies independent from pollen (varves, tree rings, elemental analyses, mineralogy, stable isotopes, and others similar) to reconstruct past climates is preferred. In the case of Lake Montcortès, the varved nature of its sediments and the availability of dendroclimatological studies in neighboring areas have allowed reconstruction of high-resolution paleotemperature and paleoprecipitation series [44,45], which have been used to study the responses of forests to past climatic shifts over the last five centuries, which corresponds to the DR3 cycle of this paper. Summer temperature/drought and autumn precipitation, along with their synergies with anthropogenic activities, have been identified as the most influential parameters in forest clearing and recovery.…”

Do Changes of Rainfall Trends Affect Choice of Drainage Systems?

“…However, there are also research indicate that increasing trend is not typical for each place. For example in Poland on the base of precipitation data from 1951-2009, it was found increasing precipitation trend in Podkarpacie Voivodeship and in the same time decreasing trend was noticed in west part of Poland [3,5,7,8,6,9,10] The paper contains results of analysis a daily precipitation data, from 17 stations located in Lubuskie Voivodeship, which were collected over the past 40 years. In climatologic time series, tests for finding the trends can be categorized as parametric and non-parametric methods.…”