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 hydroclimate processes in the past. We used simulations from the Paleoclimate Model Intercomparison Project 4th phase (PMIP4) to evaluate and reconstruct the precipitation characteristics of the Levant. First, we identified the Alfred Wagner Institute Earth System Model to largely resemble proxy reconstructions. Then we used it to understand the variability of hydroclimate. We examined changes in the frequency, seasonality, and persistence of the Levant's rain-bearing weather types, including Cyprus Lows and Red Sea Troughs. We further decomposed the dynamic and thermodynamic contributions to changes in the water balance of precipitation minus evaporation, comparing the Last Interglacial peak with preindustrial time. 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, with higher precipitation during Red Sea Trough days, resulting primarily from thermodynamic changes. Minor differences in these weather types' characteristics were found. Our research provides insights into historical hydroclimate changes in the Levant, extending our perspective on future climate impacts driven by natural variability.