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Changes in the frequency of temperature extremes are often attributed to global warming. The recent availability of near‐surface temperature data records from reference networks, such as the U.S. Climate Reference Network (USCRN), enables the quantification of measurement uncertainties. Within an activity of the Copernicus Climate Change Service, the estimation of the measurement uncertainty has been provided for USCRN temperature data, using metadata made available by the National Oceanic and Atmospheric Administration (NOAA). In this paper, four climate extreme indices (Frost Days, Summer Days, Ice Days, Tropical Nights) and the related uncertainties are calculated for the period 2006–2020 from the USCRN data set and compared with traditional indices. Moreover, the asymmetric USCRN measurement uncertainties are propagated to estimate the uncertainties of climate indices. The comparison shows expanded uncertainties homogeneously distributed with the latitude and typically within 15 days per year for Frost Days and within 10 days for Ice Days, while smaller uncertainties are estimated for Summer Days and Tropical Nights, with values typically within six to seven days per year. Positive uncertainties are typically larger than negative ones for all the indices. The values of Frost and Ice Days with the related uncertainties for USCRN have also been compared with the corresponding values calculated from reanalyses data, showing differences typically within 60 days for median values, quite often smaller than USCRN and inconsistent within the related uncertainties, Overall, the results show that USCRN measurement uncertainties increase confidence in the estimation of climate extreme indices and decisions for adaptation. Plain Language Summary: The relationship between the intensity and frequency of extremes and climate change as well as their attribution to human activities is fundamental for improving the assessment of risk and the elaboration of adaptation strategies. Temperature extremes are often reported and estimated using observations or model data using indices, which are widely adopted in the research community and by decision‐makers. However, the number of temperature extremes is quantified assuming input observations as perfect, whereas these are always affected by uncertainties due to instrumental noise and systematic effects that cannot be always properly accounted for. This also implies that climate extreme indices may under or over‐represent the number of temperature extremes. The advent of reference measurement networks, as well as the overall increase in observational data quality due to recent technological improvements, allows us to quantify measurement uncertainties in detail. In this paper, temperature extremes over the US are estimated from near‐surface temperature measurements provided by the USCRN network in the period 2006–2020 with related uncertainties. The use of uncertainty illustrates the range of values that climate extreme indices may assume. Possible sources of uncertainties and comparisons with data from atmospheric reanalysis are also discussed. Key Points: An extensive assessment of uncertainties for four climate extreme indices is provided using reference near‐surface temperaturesEstimate uncertainties of climate indices for reanalysis validation and quantification of extremes by propagating measurement uncertaintiesUSCRN traceable measurements with quantified uncertainties increase confidence in estimating extreme indices and decisions for adaptation [ABSTRACT FROM AUTHOR]

Thirteen samples of mortar collected from different masonry structures of the Curia of Pompey the Great and from three mixtilinear basins located within the Sacred Area of Largo Argentina of Rome were studied. Despite the use of the same volcanic deposit, known as 'Pozzolane Rosse', to produce the fine aggregate in all these mortars, it was possible to highlight some distinctive features through the combination of geochemical analyses on selected trace elements and petrographic analysis under an optical microscope, allowing the three groups of mortars to be distinguished. These types of mortars reflect a perfect coincidence between the diversity of the volcanic materials used and the different construction phases identified and documented by the analysis of the stratigraphic units: a first construction phase of Pompeian age, a second phase of Augustan age and a final phase in the medieval period. Furthermore, it was possible to ascertain two phases of construction of the basins, the second coeval with the interventions of the Augustan period. Finally, this study increases knowledge about the methods of exploitation and selection of volcanic materials used to produce mortars in the Roman period, identifying additional elements useful to establish their origin and chronology of use. [ABSTRACT FROM AUTHOR]

Observational records are more often than not influenced by residual non‐climatic factors which must be detected and adjusted for prior to their usage. In this work, we present a novel approach, named Radiosounding HARMonization (RHARM), providing a homogenized data set of temperature, humidity and wind profiles along with an estimation of the measurement uncertainties for 697 radiosounding stations globally. The RHARM method has been used to adjust twice daily (0000 and 1200 UTC) radiosonde data holdings at 16 pressure levels in the range 1,000–10 hPa, from 1978 to present, provided by the Integrated Global Radiosonde Archive. Relative humidity (RH) data are limited to 250 hPa. The applied adjustments are interpolated to all reported levels. RHARM is the first data set to provide homogenized time series with an estimation of the observational uncertainty at each sounding pressure level. By construction, RHARM adjusted fields are not affected by cross‐contamination of biases across stations and are fully independent of reanalysis data. Analysis of trends for temperature, RH and winds highlights increased geographical coherency of trends over 1978–2000 globally, but especially in the Northern Hemisphere and South America. RHARM shows warming trends of 0.39 K/decade at 300 hPa in the Northern Hemisphere and of 0.25 K/decade in the tropics. The RHARM adjustments also reduce differences with the European Centre for Medium‐Range Weather Forecast ERA5 reanalysis, with the strongest effect in the Northern Hemisphere for temperature and relative humidity. For wind speed, the comparison indicates a good agreement with ERA5 in the troposphere. Plain Language Summary: Systematic observations of atmospheric parameters by balloon soundings have been collected regularly across the globe since decades. However, changes in the instrumentation, calculation algorithms, station re‐locations and other factors can influence the measurement time series, making the identification of climate signals difficult. The availability of measurement metadata, cross‐comparison with (sparser) reference networks and the application of statistical methods allows to greatly improve the physical consistency of the records. We developed the Radiosounding HARMonization (RHARM) methodology to provide users with homogenized radiosonde profiles of temperature, humidity, and wind, along with measurement uncertainties, for 697 locations globally and twice daily based on the Integrated Global Radiosonde Archive. Key features of RHARM are the provision of multiple fundamental atmospheric parameters, adjusted for spurious biases and the inclusion of measurement uncertainties estimated following the standards of the metrological community when available metadata permits. The current version of the RHARM data set can be used to investigate tropospheric weather and climate for the last four decades. Key Points: The Radiosounding HARMonization (RHARM) data set provides homogenized time series of temperature, relative humidity and wind profiles for hundreds of radiosonde stationsMetrologically accurate estimates of the observational uncertainty are provided together with each observation and variableFor all variables, RHARM increases the geographical coherency of estimated trends and the agreement with a modern atmospheric reanalysis [ABSTRACT FROM AUTHOR]

Tufo Lionato is a volcanic tuff that was used extensively for construction in Rome, Italy, during antiquity and after; at least three varieties can be identified: Anio, Monteverde, and Portuense. The widespread introduction of Tufo Lionato in Roman construction is generally dated to the mid‐second century before the common era (B.C.E.). Another tuff, Lapis Albanus, is held to have been introduced during the third century B.C.E. Due to their similar macroscopic appearance, it is impossible to reliably distinguish visually among varieties of Tufo Lionato, or between Lapis Albanus and other "peperino" tuffs, nor does geochemistry alone always allow definitive identifications. A combination of geochemical and petrographical analyses is presented here, to provenance building stone from the Roman temples of Fortuna and Mater Matuta at Sant'Omobono in Rome. The combination of techniques allows for secure identification of Anio tuff and Lapis Albanus, and their use in structures of the fourth–third and fifth–third centuries B.C.E., respectively, one to two centuries earlier than previously demonstrated. These findings show a diversification of tuffs used by the Roman construction industry earlier than henceforth acknowledged, and suggest the ability of archaeometric techniques to bring new perspectives even to such familiar archaeological contexts as the city of Rome. [ABSTRACT FROM AUTHOR]

ABSTRACT Integrated 40Ar/39Ar, trace-element, stratigraphic, palaeontological and palaethnological data provide geochronological and biochronological constraints for the sedimentary and tectonic history of a Middle Pleistocene fluvial-lacustrine basin near Rome (Cretone Basin, central Italy), which has yielded a significant record of mammal fossil remains and Palaeolithic industry. This work is a case study of the interplay between tectonics and glacio-eustacy, which strongly influenced the evolution of the Tyrrhenian Sea margin of central Italy. Dating of tephra layers interbedded within the Cretone Basin lacustrine succession and reconstruction of relict terraced surfaces allow correlation with similar, geochronologically constrained, marine isotopic stages (MIS) 15-5 terraced deposits along the coast. Coupled extensional tectonics and regional uplift over the last 600 ka caused the progressive uplifting and westward migration of the main fluvial-lacustrine basin and the formation of a smaller satellite basin at its eastern margin. Here, stable environmental conditions during MIS 13-5 indicated continuous human and large mammal frequentation, as testified by lithic industry and fossil remains ascribable to the Acheulean and later early Middle Palaeolithic technocomplexes and Galerian-Aurelian mammal faunas, respectively. In addition to providing independent age constraints to glacial sea-level oscillations of this region, the reconstructed chronostratigraphic setting for the Cretone Basin provides evidence for one of the oldest Acheulean lithic assemblage of central Italy, as well as new biochronological and palaeobiogeographical data for some Middle Pleistocene mammal species of Italy. [ABSTRACT FROM AUTHOR]