European warm-season temperature and hydroclimate since 850 CE

Abstract

The long-term relationship between temperature and hydroclimate has remained uncertain due to the short length of instrumental measurements and inconsistent results from climate model simulations. This lack of understanding is particularly critical with regard to projected drought and flood risks. Here we assess warm-season co-variability patterns between temperature and hydroclimate over Europe back to 850 CE using instrumental measurements, tree-ring based reconstructions, and climate model simulations. We find that the temperature-hydroclimate relationship in both the instrumental and reconstructed data turns more positive at lower frequencies, but less so in model simulations, with a dipole emerging between positive (warm and wet) and negative (warm and dry) associations in northern and southern Europe, respectively. Compared to instrumental data, models reveal a more negative co-variability across all timescales, while reconstructions exhibit a more positive co-variability. Despite the observed differences in the temperature-hydroclimate covariability patterns in instrumental, reconstructed and model simulated data, we find that all data types share relatively similar phase-relationships between temperature and hydroclimate, indicating the common influence of external forcing. The co-variability between temperature and soil moisture OPEN ACCESS RECEIVED

Monthly storminess over the Po River Basin during the past millennium (800–2018 CE)

“…This may demonstrate that dynamic atmospheric processes are present in generating cyclone-related precipitation extremes throughout the LIA (Raible et al 2018), departing from the Clausius-Clapeyron thermodynamic expectations of an increase in precipitation intensity associated with atmospheric warming (Pall et al 2007, Trenberth 2011, Trenberth et al 2014, Kirby 2016, Prein and Pendergrass 2019. Our study thus shows the same tendency as revealed by Ljungqvist et al (2019) for a negative low-frequency temperature-hydroclimatic coupling (i.e., warm and dry) in southern Europe. Likewise, solar-type periodicities suggest that the Sun may be one of the precursors of hydrological processes in northern Italy (Zanchettin et al 2008).…”

“…This is distinctly visible in figure 4(a), which shows that ASSIS(GF) is only little accentuated in this drier period in the ninth and tenth centuries. Between c. 750 and 1250 CE, southern Europe, including northern Italy, tended to receive relatively low amounts of precipitation, at least in summer, whereas the temperature, on average, was higher (Luterbacher et al 2016, Ljungqvist et al 2019.…”

“…There has been increasing interest in the hydroclimatic response to large-scale environmental changes such as ongoing global warming (e.g., Luo et al 2018, Orth and Destouni 2018, Ljungqvist et al 2016, 2019) and largescale urbanization (e.g., Debbage andShepherd 2018, Paul et al 2018), including active construction sites (e.g., Ricks et al 2020). Water is not only a valuable natural resource and societal asset, but has also the potential to inflict damage on human society and the environment, causing large disasters and financial losses (Hoeppe 2016, Brown et al 2018.…”

Close co-variation between soil moisture and runoff emerging from multi-catchment data across Europe

“…Europe also spans steep climate gradients, such that we can study the targeted possible emergent large-scale patterns of soil moisture co-variation with other hydro-climatic variables in and across the three main European climate regions distinguished and proposed by the Intergovernmental Panel on Climate Change (IPCC) as appropriate for managing risks of extreme events and advancing climate change adaptation 2 : Northern Europe (NEU), Central Europe (CEU), and Southern Europe (SEU). Recent large-scale multi-catchment studies of current 5 and past 26 hydro-climate across Europe have also shown distinctly different large-scale characteristics of these three climate zones with regard to soil moisture anomaly responses to atmospheric driver variations. To also assess data uncertainty effects, the analysis combines the three alternative data products into a fully independent set for a basic study, as well as an internally consistent and an intermediate dataset for comparative study (Table 1).…”

Recovering Climate Data from Documentary Sources: A Study on the Climate in the South of Spain from 1792 to 1808

“…Terms used in the CMEI to describe the meteorological events and the assigned indices (i t = temperature index; i r = precipitation index). It is interesting to consider the combined effect of the thermal and pluviometric (rainfall) regimes [22,23]. To do this, the differences between the percentages of wet and dry (warm and cold) weather records were calculated for each year and represented, as shown, in Figure 3d.…”