An endless summer: 2018 heat episodes in Europe in the context of secular temperature variability and change

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Observational and Modelling Study of a Major Downburst Event in Liguria : the 14 October 2016 Case

Downbursts are very disruptive weather events that can produce large amounts of damage. The most studied downbursts are those occurring in the United States and continental Europe, but they can happen globally. This work is an observational and modelling analysis of a major downburst event that occurred on 14 October 2016 over eastern Liguria (Italy). This downburst affected an area 30 km long and 10 km wide, producing observed wind gusts of 40 m/s with major impacts to railways, trees, and houses, with more than 2.5 million euros of damage. First, the general environment influencing this downburst is identified and analyzed, then the event is reproduced with a small multi-physics high-resolution ensemble using the Weather Research and Forecasting (WRF)-advanced research WRF (ARW) model, with 1 km horizontal grid spacing. The event was poorly predicted beforehand, and the difficulty in forecasting this event is confirmed by the fact that so few ensemble members suggested the occurrence of damaging winds over eastern Liguria. However, one of the eight members performed well and its output helped to reveal the primary mechanisms for the downburst, suggesting that high-resolution ensembles using mixed physics may be a useful tool for improving the prediction of similar extreme events in the Mediterranean region in the future

Modelling shortwave and longwave downward radiation and air temperature driving ablation at the Forni Glacier (Stelvio National Park, Italy)

We focus here on modelling the meteorological parameters most influencing snow/ice melting over an alpine glacier. Specifically, we consider shortwave and longwave downward radiation, and air temperature. We set up and test a methodology for their accurate distribution at the glacier surface, which can be applied whenever: i) supraglacial meteoro-logical measurements are available or ii) weather data are acquired from a station quite close to the glacier. As a suitable site to test our approach we selected the Forni Glacier, in the Italian Alps, where an Automatic Weather Station (AWS) has been running since autumn 2005 thus giving a robust dataset for developing a field based modeling approach. First, we modelled and distributed the incoming solar radiation by taking into account actual atmospheric conditions, glacier topography and shading. Then, we modelled the incoming longwave radiation considering cloud-cover and air temperature. Third, we investigated a local lapse rate to depict the yearly variability of the vertical air temperature gradient, to assess the actual thermal conditions at different elevations. Finally, we compared the modeled values against data collected on the field. The results display that during the glacier ablation period (i.e.: May-September): i) our approach provides a good depiction of both point incoming solar and infrared radiation fluxes, ii) the spatial distribution of the incoming solar radiation we developed is satisfactory, iii) our tests suggest that the incoming longwave fluxes can be considered constant over the whole glacier ablation area thus neglecting its spatial distribution, and iv) the application of a local lapse rate provides a good distribution of air temperature at the glacier surface

High-Resolution Monthly Precipitation Fields (1913–2015) over a Complex Mountain Area Centred on the Forni Valley (Central Italian Alps)

Mountain environments are extremely influenced by climate change but are also often affected by the lack of long and high-quality meteorological data, especially in glaciated areas, which limits the ability to investigate the acting processes at local scale. For this reason, we checked a method to reconstruct high-resolution spatial distribution and temporal evolution of precipitation. The study area is centred on the Forni Glacier area (Central Italian Alps), where an automatic weather station is present since 2005. We set up a model based on monthly homogenised precipitation series and we spatialised climatologies and anomalies on a 30-arc-second-resolution DEM, using Local Weighted Linear Regression (LWLR) and Regression Kriging (RK) of precipitation versus elevation, in order to test the most suitable approach for this complex terrain area. The comparison shows that LWLR has a better reconstruction ability for winter while RK slightly prevails during summer. The results of precipitation spatialisation were compared with station observations and with data collected at the weather station on Forni Glacier, which were not used to calibrate the model. A very good agreement between observed and modelled precipitation records was pointed out for most station sites. The agreement is lower, but encouraging, for Forni Glacier station data

PATTERNS OF PRECIPITATION VARIABILITY IN THE GREATER ALPINE REGION

A recently set up and homogenised new precipitation dataset for the Greater Alpine Region (GAR) is presented here with some first preliminary analyses. Climate change patterns within the study region are analysed in terms of regionally different evolutions, seasonality, and short to long-term trends. It will be shown that precipitation presents pronouncedly different variability patterns in space as well as in terms of seasonality and at different time scales

Snow data intercomparison on remote and glacierized high elevation areas (Forni Glacier, Italy)

Abstract. We present and compare 11 years of snow data (snowfall, snow depth and snow water equivalent (SWE)) measured by an Automatic Weather Station and by some field campaigns on the Forni Glacier. The data have been acquired by means of (i) a Campbell SR50 sonic ranger from October 2005 (snow depth data), (ii) manual snow pits from January 2006 (snow depth and SWE data), (iii) a Sommer USH8 sonic ranger from May 2014 (snow depth data), (iv) a Park Mechanical SS-6048 snow pillow from May 2014 (SWE data), (v) a manual snow weighting tube (Enel-Valtecne©) from May 2014 (snow depth and SWE data). The aim of the analyses is to assess the mean value of fresh snow density and the most appropriate method to evaluate SWE for this measuring site. The results indicate that the daily SR50 sonic ranger measures allow a rather good estimation of the SWE, and the provided snow pit data are available for defining the site mean value of fresh snow density. For the Forni Glacier measuring site, this value turned out to be 140 kg m−3. The SWE derived from sonic ranger data is rather sensitive to this value: a change in fresh snow density of 20 kg m−3 causes a mean variation in SWE of ±0.093 m w.e. for each hydrological year, ranging from ±0.050 m w.e. to ±0.115 m w.e

X‐ray microtomography and phylogenomics provide insights into the morphology and evolution of an enigmatic mesozoic insect larva

Fossils sometimes show unusual morphological features absent in living organisms, making it difficult to reconstruct both their affinity and their function. We describe here a new lacewing larva, Ankyloleon caudatus gen. et sp.n. (Neuroptera) from the Cretaceous amber of Myanmar, characterized by an abdomen unique among insects, with ‘tail-like’ terminal segments bearing a ventral pair of vesicles. Phase-contrast X-ray microtomography reveals that these structures were dense and equipped with a median duct, suggesting that they were likely pygopods used for locomotion, holding the position through adhesive secretions. Our phylogenetic analyses, combining genomic and morphological data from both living and fossil lacewings, proved critical to placing Ankyloleon gen.n. on the lacewing tree of life as an early representative of the antlion clade, Myrmeleontiformia. These results corroborate the view that derived myrmeleontiform lacewings ‘experimented’ with unusual combinations of features and specializations during their evolutionary history, some of which are now lost