Hydroclimatic variability and weather type characteristics in the Levant during the last interglacial

Abstract. Proxy-based reconstructions of the Last Interglacial peak indicate changes in precipitation characteristics in the Levant. These reconstructions suggest that precipitation occurred in brief and intense events, particularly in the region's southern parts. Some studies have offered conflicting paradigms for explaining hydroclimate variability. However, these have yet to be consistently tested in a modeling framework. Indeed, the modeling approach can undoubtedly enhance the combined interpretation of proxy records and our understanding of past hydroclimate processes. We use simulations from the Paleoclimate Model Intercomparison Project 4th phase (PMIP4) to evaluate and reconstruct the precipitation characteristics of the Levant. First, we identify the Alfred Wagner Institute Earth System Model as one that largely resembles proxy reconstructions. Then we use it to understand hydroclimate variability. We examine changes in the frequency, seasonality, and persistence of the Levant's rain-bearing weather types, including Cyprus Lows and Red Sea Troughs. We further decompose the dynamic and thermodynamic contributions to changes in the water balance, comparing the Last Interglacial peak with Pre-Industrial times. Based on differences in daily mean precipitation, we provide evidence that the rain-bearing weather types yielded significantly more precipitation (≈+20%) during the Last Interglacial peak. This increase is most evident in the southern Levant, where higher precipitation occurs during Red Sea Trough days, primarily due to thermodynamic changes. Minor differences in the frequency and persistence of these weather types were found. Our research offers insights into historical hydroclimate changes in the Levant, broadening our understanding of future climate impacts driven by natural variability.