Precipitation Record Research Articles

Moisture sources and synoptic conditions of summer precipitation in the glacial zone of the East Sayan Range

Abstract. Precipitation in high-mountain regions is characterized by a strong heterogeneity due to complex interaction between atmospheric circulation and steep topography, however, extremely rare network of high elevation stations hampers the adequate high resolution regional climate modeling. In this study we present new data of precipitation directly measured in high-mountain catchment, on the continental glacier (East Sayan Range, south of East Siberia) during the summer periods of 2015–2017 using automatic weather station. The precipitation record was compared with near located weather stations and ERA Interim and NCEP/NCAR reanalysis data. Precipitation mode similar to the glacier site was found at the stations located west and northwest, while ERA Interim and NCEP/NCAR reanalysis data underestimated the precipitation by 40 % and 70 %, respectively. Atmospheric circulation patterns in days with precipitation were analyzed by using mean sea level pressure, geopotential height at 700 and 500 hPa and classification of macro scale atmospheric processes of the Northern Hemisphere by Dzerdzeevskii. Summer precipitation was mostly associated with meridional southern group of large scale circulation the Northern Hemisphere, while at synoptic scale it basically fell in cyclonic (49 % of precipitation) and low-gradient cyclonic (30 %) baric fields. Six typical atmospheric circulation patterns over the East Sayan were identified for days with precipitation. The sources and atmospheric moisture transfer to the glacier was defined by using the HYSPLIT trajectory model. The most of summer precipitation (70 %) was related with western cyclones, while about 25 % of rainfalls (mainly of moderate to strong intensity) was originated from the south-east (Pacific monsoon influence).

Initiation of a stable convective hydroclimatic regime in Central America circa 9000 years BP

Many Holocene hydroclimate records show rainfall changes that vary with local orbital insolation. However, some tropical regions display rainfall evolution that differs from gradual precessional pacing, suggesting that direct rainfall forcing effects were predominantly driven by sea-surface temperature thresholds or inter-ocean temperature gradients. Here we present a 12,000 yr continuous U/Th-dated precipitation record from a Guatemalan speleothem showing that Central American rainfall increased within a 2000 yr period from a persistently dry state to an active convective regime at 9000 yr BP and has remained strong thereafter. Our data suggest that the Holocene evolution of Central American rainfall was driven by exceeding a temperature threshold in the nearby tropical oceans. The sensitivity of this region to slow changes in radiative forcing is thus strongly mediated by internal dynamics acting on much faster time scales.

Hydrometeorological processes in semi-arid western India: insights from long term isotope record of daily precipitation

Long term (2005–2016) daily precipitation isotope data (δ18O, δD and d-excess) from Ahmedabad in semi-arid Western India are examined in light of various meteorological parameters and air parcel trajectories to identify prominent patterns in the isotopic character and discern the underlying hydrometeorological processes. One of the most prominent and systematic annual patterns is the isotopic depletion (average δ18O: − 2.5‰ in Jun–Jul; − 5.2‰ in Aug–Sept) in the second half of the Indian Summer Monsoon (ISM), which is observed in the 11 out of the 12 years of this study. Four geographically feasible causal factors have been examined if they contribute to observed late monsoon isotopic depletion. These factors are: (1) increased contribution of terrestrially recycled vapor; (2) intra-seasonal change in sea-surface, surface-air and cloud base temperatures; (3) increased rain-out fraction from marine vapor parcel; and (4) increase in relative proportion of convective rain. It is inferred from the present study that isotopic depletion in the second half of ISM is associated with: (1) increased contribution (45% from 36%) of terrestrially recycled moisture; (2) 1.9° C lower cloud base temperature; (3) increased rainout fraction due to decreased wind velocity (6.9 m/s from 8.8 m/s); and (4) an increase of 22.3% in the proportion of convective rain. Daily rain events with atypical isotopic composition (20‰ < d-excess < 0‰) are ascribed mainly to local weather perturbations causing sudden updraft of moist air facilitating terrestrial recycling of water vapor.

Interannual Southern California Precipitation Variability During the Common Era and the ENSO Teleconnection

AbstractSouthern California's Mediterranean‐type hydroclimate is highly variable on interannual time scales due to teleconnected climate forcings such as the El Niño–Southern Oscillation (ENSO). Here we present subannually resolved scanning X‐ray fluorescence Ti counts from deep‐sea cores in Santa Barbara Basin, California, recording 2,000 years of hydroclimate variability. The reconstructed Southern California precipitation record contains interannual variability in the 2‐ to 7‐year band that could be driven by changes in tropical Pacific ENSO variability and/or the strength of the ENSO teleconnection modulated by extratropical pressure systems. Observed interannual precipitation variance increased and was associated with longer periodicities (5–7 years) when the Intertropical Convergence Zone migrated southward (1370–1540 CE) and the Aleutian Low strengthened creating a robust ENSO teleconnection. Weak interannual precipitation variance with shorter periodicity (2–3 years) was observed when the Intertropical Convergence Zone shifted northward (700–900 CE) and/or the Aleutian Low was weak (1540–1680 CE).

Long-Term Isotope Records of Precipitation in Zagreb, Croatia

The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (3H activity concentration, δ2H, δ18O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition reflected observed climate changes in Zagreb: a significant increase in the annual air temperature and larger variations in the precipitation amount. Annual mean δ18O and δ2H values showed an increase of 0.017‰ and 0.14‰ per year, respectively, with larger differences in monthly mean values in the first half of the year than in the second half. Mean annual d-excess remained constant over the whole long-term period, with a tendency for monthly mean d-excess values to decrease in the first half of the year and increase in the second half due to the influence of air masses originating from the eastern Mediterranean. Changes in the stable isotope composition of precipitation thus resembled changes in the temperature, the circulation pattern of air masses, and the precipitation regime. A local meteoric water line was obtained using different regression methods, which did not result in significant differences between nonweighted and precipitation-weighted slope and intercept values. Deviations from the Global Meteoric Water Line GMWL (lower slopes and intercepts) were observed in two recent periods and could be explained by changes in climate parameters. The temperature gradient of δ18O was 0.33‰/°C. The tritium activity concentrations in precipitation showed slight decreases during the last two decades, and the mean A in the most recent period, 2012–2018, was 7.6 ± 0.8 Tritium Units (TU).

Tipping bucket raingauge with GPRS data logger DL-2016: Specifications, installation, and analysis

Rain sustains life by providing the means for transferring water from the atmosphere to the surface, and it is an important measure and predict local and global rainfall behavior to understand the water cycle better. Mainly agricultural engineers, civil engineers want to know the precipitation statement and capacity of water for the catchment area. For that, install a rain gauge and data analysis. Among all rain gauges (recording and nonrecording), the tipping bucket rain gauge works very efficiently, accurately, and economically also. For this project, selected tipping bucket rain gauge with GPRS based data logger DL-2016 for data storage with a longer time. A placed rain gauge on top of the roof with the constructed block (dimensions 0.46 * 0.46 m2, and the height is 1 m). We built the block with the aspects of the regular brick. In the neighborhood, we constructed the concrete bed with 0.15 m height with M30 grade concrete. On the practical bed, we placed two wooden blocks with dimensions of 0.08 * 0.45 m2 after rain gauge set on the woodblocks. After construction of the block and installation of the rain gauge, have to give a power connection to a data logger with extended wire. Actually, can not place data logger under precipitation due problematic with data storage and power connection. Hypertrm software used to retrieve the precipitation recordings from the GPRS based data logger DL-2016. The user has to perform, however, several additional data filtering and processing operations before storing the records in the final database. From GPRS based datalogger DL-2016. Major all industries, irrigation, drinking, and municipalities depend on precipitation. In this project, selected recording type of rain gauge for determining annual data and installation in ABR College. From rain gauge, get data for a given time to analyze and calibrate precipitation. Hydrographs do calibration and analysis in that unit-hydrographs. Draw hydrograph From rain gauge for precipitation data in ABR collage catchment, we are installing tipping bucket rain gauge (recording type rain gauge) on the top floor with following standards from the data logger we get data in terms of precipitation intensity with time. So from this data, we can analyze precipitation in the ABR college as a catchment area.

Change in climate withered an empire

Anthropology From roughly 912 to 609 BCE, the Neo-Assyrian Empire rose as one of the most powerful superpowers of its time, dominating much of the Near East. Sinha et al. propose that megadroughts played an important role in the rapid decline in the empire's power, from its height around 670 BCE to its collapse only six decades later. Precisely dated cave deposits from northern Iraq preserved a record of precipitation and effective moisture over a 4000-year period that includes the span of the Neo-Assyrian Empire. This record demonstrates that the rise of the empire occurred during a roughly 200-year interval of abundant rainfall. Subsequently, severe megadroughts characterized the climate across the empire, likely contributing to the empire's rapid decline. Sci. Adv. 10.1126/sciadv.aax6656 (2019).

A Rainwater Harvesting Accounting Tool for Water Supply Availability in Colorado

Rainwater harvesting (RWH) is a renewable water supply option for nonpotable use, most commonly used for landscaping irrigation. Water rights in Colorado prohibit all RWH except residential rain barrels and a pilot project program that allows centralized rainwater harvesting for new development. Development of a natural catchment creates impervious surfaces, thereby increasing runoff, with a subsequent decrease in infiltration and losses to evapotranspiration; pilot projects are allowed to harvest a volume equal to the predevelopment runoff losses that would have occurred on new impervious areas at the site. To support this administrative policy, a tool was developed for the efficient calculation of daily allowable harvest at nearly any project site in Colorado. A reliable and useful policy tool requires the incorporation of hydrologic science with widely applicable, user-friendly design, a challenging balance of rigor and accessibility that is welcomed by engineers and policymakers alike. The daily allowable harvest is determined for each soil group as a percentage of infiltrated rainfall less the groundwater return. Horton’s infiltration method is used to model rainfall‒runoff for a range of soil parameters (NRCS hydrologic soil groups) and precipitation events (0.25- to 25-year return periods and 15-min to 24-h durations). For most events, the percent infiltration is 90% of the precipitation depth; this ratio decreases when precipitation exceeds the infiltration rate. Results are simplified in a spreadsheet tool for policy application, with allowable harvest rules binned by event duration and frequency. Simulations using the tool for a 2010‒2017 precipitation record from Colorado’s Front Range showed that RWH can supply up to 50% of the annual demand for traditional landscaping and over 100% of the water-smart landscaping demand.

A 68 ka precipitation record from the hyperarid core of the Atacama Desert in northern Chile

Abstract The Atacama Desert in northern Chile is one of the driest deserts on Earth. Hyperaridity persists at least since the Miocene and was punctuated by pluvial phases. However, very little is known about the timing, regional spread and intensities of precipitation changes. Here, we present a new precipitation record from a sedimentary sequence recovered in a tectonically blocked endorheic basin that is located in the hyperarid core of the Atacama Desert. The chronostratigraphic framework of the record is given by a multi-disciplinary dating approach, suggesting an age of ca. 68 ka BP for the core base. The sequence consists of three sediment types, whose sedimentological and geochemical characteristics suggest different depositional processes that reflect different degrees in humidity. First, particularly fine-grained sediments with high clastic but low calcium sulfate and carbonate contents reflect a particularly dry climate with only sporadic precipitation events and fluvial supply via channel systems. Second, more coarse-grained sediments with lower clastic and higher calcium sulfate and carbonate contents reflect more moist conditions with stronger precipitation events that lead to fluvial activity not restricted to the channels but involving the slopes and plains in the catchment. Third, normally graded layers with an equally high proportion of calcium sulfate and carbonate reflect occasional high-precipitation events that caused sediment supply also from most distant parts of the catchment via severe flash floods. The sedimentary succession suggests that precipitation changes took place on orbital but also on millennial time scales. Rather moist periods occurred during most of MIS 2, several shorter periods within MIS 3 and parts of MIS 4. Comparison of the findings from the Huara record with selected climate records from continental and marine sites in South America suggests a strong precipitation heterogeneity across the Atacama. This heterogeneity is caused by pronounced differences in the dominating climate patterns and a shift from predominant summer rain in the north to winter rain in the south. Precipitation supply to the Huara clay plan is controlled by the atmospheric circulation rather than the surface temperature of the adjacent ocean.

Multidecadal Climate Variability and the Florescence of Fremont Societies in Eastern Utah

Fremont societies of the Uinta Basin incorporated domesticates into a foraging lifeway over a 1,000-year period from AD 300 to 1300. Fremont research provides a unique opportunity to critically examine the social and ecological processes behind the adoption and abandonment of domesticates by hunter-gatherers. We develop and integrate a 2,115-year precipitation reconstruction with a Bayesian chronological model for the growth of Fremont societies in the Cub Creek reach of Dinosaur National Monument. Comparison of the archaeological chronology with the precipitation record suggests that the florescence of Fremont societies was an adaptation to multidecadal precipitation variability with an approximately 30-plus-year periodicity over most, but not all, of the last 2,115 years. Fremont societies adopted domesticates to enhance their resilience to periodic droughts. We propose that reduced precipitation variability from AD 750 to AD 1050, superimposed over consistent mean precipitation availability, was the tipping point that increased maize production, initiated agricultural intensification, and resulted in increased population and development of pithouse communities. Our study develops a multidecadal/multigenerational model within which to evaluate the strategies underwriting the adoption of domesticates by foragers, the formation of Fremont communities, and the inherent vulnerabilities to resource intensification that implicate the eventual dissolution of those communities.

Tool for Monitoring Hillslope Stability Considering Precipitation Data

This work presents a methodology applied to the monitoring of slope stability in a rural area in Manizales, using the hillslope-storage Boussinesq (HSB) partial differential equation. This was applied with theoretical information of geotechnical parameters, such as porosity, hydraulic conductivity, thickness and data obtained from indirect measures such as the angle of the hillslope, width of the hillslope, profile of the hillslope and precipitation. In this work, the HSB equation was solved with the finite differences method by applying the python programming in four days of precipitation. The precipitation was reported by the EMAS meteorological station. The result was the saturation curve and its safety factor for each daily record of precipitation in each one of the scenarios given, when varying depth along the hillslope. This methodology can contribute to the monitoring of hillslopes located in rural areas as long as the values of the geotechnical parameters are adjusted, enabling to add to the efforts aimed at an early warning system for the hazard of landslides.

The Beccari series of precipitation in Bologna, Italy, from 1723 to 1765

The precipitation record taken by J.B. Beccari in Bologna from 1723 to 1765, with three observations a day, has been recovered from the original Logs and analysed. Although metadata are scarce or even missing, a thorough investigation of the contemporary sources, the interactions between Beccari, his colleagues in Padua, and the Royal Society London, as well as the record analysis, have allowed reconstruction of most of the information concerning the instrument, its location and exposure, the measuring protocol and units. Daily, monthly and yearly amounts and frequencies, as well as extreme events, have been analysed. The first decade (i.e. 1723–1733) was drier than the 1961–1990 reference period and the subsequent decades wetter. During the calendar year, summer was dryer and October was characterized by a stronger activity of Atlantic perturbations.

Atacama’s Past Rainfall Followed Pacific Sea Temperature

This is the first paleoclimate record of precipitation near Atacama’s hyperarid core and suggests that its moisture source is different from that of the Andes.

Late onset of the Holocene rainfall maximum in northeastern China inferred from a pollen record from the sediments of Tianchi Crater Lake

AbstractThe timing of the Holocene summer monsoon maximum (HSMM) in northeastern China has been much debated and more quantitative precipitation records are needed to resolve the issue. In the present study, Holocene precipitation and temperature changes were quantitatively reconstructed from a pollen record from the sediments of Tianchi Crater Lake in northeastern China using a plant functional type-modern analogue technique (PFT-MAT). The reconstructed precipitation record indicates a gradual increase during the early to mid-Holocene and a HSMM at ~5500–3100 cal yr BP, while the temperature record exhibits a divergent pattern with a marked rise in the early Holocene and a decline thereafter. The trend of reconstructed precipitation is consistent with that from other pollen records in northeastern China, confirming the relatively late occurrence of the HSMM in the region. However, differences in the onset of the HSMM within northeastern China are also evident. No single factor appears to be responsible for the late occurrence of the HSMM in northeastern China, pointing to a potentially complex forcing mechanism of regional rainfall in the East Asian monsoon region. We suggest that further studies are needed to understand the spatiotemporal pattern of the HSMM in the region.

Holocene El Ni\xf1o\u2013Southern Oscillation variability reflected in subtropical Australian precipitation

The La Niña and El Niño phases of the El Niño-Southern Oscillation (ENSO) have major impacts on regional rainfall patterns around the globe, with substantial environmental, societal and economic implications. Long-term perspectives on ENSO behaviour, under changing background conditions, are essential to anticipating how ENSO phases may respond under future climate scenarios. Here, we derive a 7700-year, quantitative precipitation record using carbon isotope ratios from a single species of leaf preserved in lake sediments from subtropical eastern Australia. We find a generally wet (more La Niña-like) mid-Holocene that shifted towards drier and more variable climates after 3200 cal. yr BP, primarily driven by increasing frequency and strength of the El Niño phase. Climate model simulations implicate a progressive orbitally-driven weakening of the Pacific Walker Circulation as contributing to this change. At centennial scales, high rainfall characterised the Little Ice Age (~1450–1850 CE) in subtropical eastern Australia, contrasting with oceanic proxies that suggest El Niño-like conditions prevail during this period. Our data provide a new western Pacific perspective on Holocene ENSO variability and highlight the need to address ENSO reconstruction with a geographically diverse network of sites to characterise how both ENSO, and its impacts, vary in a changing climate.

Eight Hundred Years of Drought and Flood Disasters and Precipitation Sequence Reconstruction in Wuzhou City, Southwest China

Natural hazards such as floods and droughts occur frequently in southwestern China and have occurred more frequently in recent years, which has caused and will continue to cause serious damage to ecosystems and human lives and property. A full knowledge of the probability of hydro climatic variables is essential for the prevention and mitigation of natural hazards in return. Based on historical archives, atlases and other documented data, a sequence of graded drought and flood disasters covering the period 1250–2000 in Wuzhou City, southwest China, was reconstructed. Then, a correlation coefficient (−0.79, p &lt; 0.01) was established between the sequence of grades and the measured annual precipitation from 1961 to 2000; using this correlation and the sequence of grades from 1250 to 2000, the annual precipitation record (from 1250 to 2000) was reconstructed and extended. Finally, we compared the reconstructed annual precipitation to the measured values from 1961–2000 to evaluate the efficacy of this method. The results show that the reconstructed precipitation sequence is credible, with a high correlation coefficient (0.84, p &lt; 0.01) and a low relative bias (−1.95%). The reconstructed results indicate that the annual precipitation in Wuzhou City increased continuously during the 13–15th century and the 18–19th century and decreased during the 16–17th century and the 20th century. These results are expected to be useful for the prevention of flood and drought impacts and for understanding climate change.

Assessing regional drought impacts on vegetation and evapotranspiration: a case study in Guanacaste, Costa Rica.

This research investigates ecological responses to drought by developing a conceptual framework of vegetation response and investigating how multiple measures of drought can improve regional drought monitoring. We apply this approach to a case study of a recent drought in Guanacaste, Costa Rica. First, we assess drought severity with the Standard Precipitation Index (SPI) based on a 64-yr precipitation record derived from a combination of Global Precipitation Climatology Center data and satellite observations from Tropical Rainfall Measuring Mission and Global Precipitation Measurement. Then, we examine spatial patterns of precipitation, vegetation greenness, evapotranspiration (ET), potential evapotranspiration (PET), and evaporative stress index (ESI) during the drought years of 2013, 2014, and 2015 relative to a baseline period (2002-2012). We compute wet season (May-October) anomalies for precipitation at 0.25° spatial resolution, normalized difference vegetation index (NDVI) at 30-m spatial resolution, and ET, PET and ESI derived with the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model at 1-km spatial resolution. We assess patterns of landscape response across years and land cover types including three kinds of forest (deciduous, old growth, and secondary), grassland, and cropland. Results show that rainfall in Guanacaste reached an all-time low in 2015 over a 64-yr record (wet season SPI=-3.46), resulting in NDVI declines. However, ET and ESI did not show significant anomalies relative to a baseline, drought-free period. Forests in the region exhibited lower water stress compared to grasslands and had smaller declines, and even some increases, in NDVI and ET during thedrought period. This work highlights the value of using multiple measures to assess ecosystem responses to drought. It also suggests that agricultural land management has an opportunity to integrate these findings by emulating some of the characteristics of drought-resilient ecosystems in managed systems.

Twenty-five year record of chemicals in open field precipitation and throughfall from a medium-altitude forest catchment (Strengbach - NE France): An obvious response to atmospheric pollution trends

This study concerned a 25 yr continuous record of bulk precipitation and throughfall composition in a medium-altitude forested environment. The 1986–2012 survey from the more intense acid rain period in the mid-eighties until the present allowed the quantification of the interaction between atmospheric deposition and vegetation and the long-term evolution following pollutant emission trends.The long-term monitoring evidenced some significant temporal trends (pH, conductivity, SO42−, Cl−, NO3−, Ca2+, Mg2+, and K+). Significant decreases in the concentrations and fluxes of several ions were observed (H+ and SO42−, Cl−, and Ca2+) in open field precipitation and throughfalls. The regular and strong decrease in protons and sulfate followed the decreases in anthropogenic SO2 and NOx (proton precursors) since the 1980s. The decrease in Cl− concentrations was weaker and could have been related to the regional reduction in HCl emissions and/or to changes in the precipitation regime. The annual calcium fluxes were reduced from approximately 15 to 9 and 6 to 2 kg ha−1 under spruces and beeches, respectively, as a consequence of reductions in anthropogenic industrial dust. In such calcium-limited resource soils, the atmospheric Ca flux exceeded the Ca flux from mineral weathering and was highly bioavailable for vegetation growth. This decrease in nutrient input had strong consequences for soil nutrients and may thus have participated in forest decline.The two tree plantations had contrasting effects on the physico-chemical parameters of the incoming precipitation with higher water interception and chemical concentrations under spruces than under beeches, which underlined the role of tree species in atmospheric inputs to soils. The structure and persistence of spruce needles enhanced the capture of particles and water, accentuating the acidity of the deposition and leading to the intensification of acidification processes, nutrient leaching in soils and forest decline. In contrast, beech leaves were able to neutralize a portion of the atmospheric protons, which minimized and reduced the negative effects of acid rain. In addition, the throughfalls represented an important part of the biological cycle of trees for some elements such as K or N, as indicated by the contrasting patterns at year and long-term scales regarding the vegetation type. However, our study indicated that the influence of tree species might change over time with changes in atmospheric pollution, in precipitation regime, or in stand structure.This study outlined the importance of the long-term record of open field precipitation and throughfalls under various tree types to better evaluate the real inputs of elements to forest ecosystems and among them, essential mineral nutrients.

Development of a Stochastic Storm Generator Using High-Resolution Precipitation Records

Abstract.Sophisticated field and watershed scale environmental models for runoff, erosion control, environmental, and global-change investigations require detailed continuous temporal and spatial inputs of precipitation to drive the hydrologic processes. For accurate estimates of these processes, the resolution of the input data must allow the representation of the variability of precipitation as it represents a major source of variability in the model outputs. Currently, the use of stochastic weather generators is widespread to generate continuous series of meteorological data at gauged and ungauged locations. These weather simulators are designed to replicate the statistical properties of real weather data at monthly or daily time resolutions. However, daily values of precipitation do not represent the variability of storm parameters within a day, which is assumed to significantly influence the predictions of environmental or agricultural models where processes are sensitive to sub-daily values. This research proposes a parsimonious stochastic storm generator based on 5-min time resolution and correlated non-normal Monte Carlo-based numerical simulation. The model considers correlated non-normal random rainstorm characteristics such as time between storms, duration, and amount of precipitation, as well as the storm intensity structure. The accuracy of the model was verified by comparing the generated rainfall with rainfall data from a randomly selected 5-min weather station in North Carolina. Current results have shown that the proposed storm generator can capture the essential statistical features of rainstorms as well as their patterns followed by their intensities, preserving the first four moments of monthly storm events, good annual extreme event correspondence, and the correlation structure within each storm. Finally, as the proposed model depends on statistical properties at a site, this may allow the use of the synthetic storms in ungauged locations provided relevant information from a regional analysis is available. Keywords: Monte Carlo, Stochastic storm generator, Storm distribution.

The influence of low-frequency variability on tree-rings based climate reconstruction: a case study from central Italy (Roman coast).

Tree rings are among the best sources of proxy data for reconstructing past climatic records. In this study we explore for the first time what type of climatic signals can be reconstructed from stone pine ( Pinus pinea L.) based on tree-rings from central Italy (Roman coast). Samples from 112 stone pine trees from stands with different age classes were collected at two locations, Castel Fusano and Castelporziano. In determining the particular target variable for climate reconstruction we explored a wide range of climatic signals (from monthly to multiple year scale) for correlations with tree ring chronologies produced using a variety of detrending methods. We reconstructed short term (autumn-early winter) and long term (3 years precipitation) signals during the 150 years of available data using the “classical” detrending method but also methods preserving their low frequency variability (ABD and RCS) within the chronologies. By setting the best multiple year precipitation drivers at an annual scale and applying a simple percentile threshold approach, we identified the wettest and driest climatic events. The best accuracy in identifying the climatic thresholds was obtained with the ABD method, which also showed the best cross spectral correlation with a long precipitation record. Our reconstruction underpins that since ca. 1850 the Roman coast has experienced its driest conditions in terms of 2-3 year rainfall sums during the last 50 years of the 20 th Century. This finding may be used in the context of identifying the long-term natural variability of the region in relation to climate change as it is expected to affect the Mediterranean.