scholarly journals Interannual analysis of high spatially-resolved δ18O and δ2H data in precipitation across North-East Italy

2020 ◽  
Author(s):  
Mauro Masiol ◽  
Daniele Zannoni ◽  
Barbara Stenni ◽  
Giuliano Dreossi ◽  
Luca Zini ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Isotopic Composition ◽  
Unconfined Aquifer ◽  
Interesting Case ◽  
Point Of View ◽  
Water Isotopes ◽  
Stable Water Isotopes ◽  
Weather Factors ◽  
North East ◽  
The North

<p>Stable water isotopes are widely-used tracers to investigate hydrological processes occurring in the atmosphere and to determine the geospatial origin of water, i.e. to acquire useful information about the hydrological cycles over catchment basins and to find the origin of water recharging rivers, aquifers, and springs. Mapping the isotopic composition of precipitation provides hydrological and climate information at regional and global scales. However, the isotopic composition of precipitation is usually analyzed at large scales with a limited spatial resolution. In Italy, a few studies mapped the oxygen stable isotopes using annually-averaged data, not accounting for the strong seasonality of the isotopic composition linked to climatic and weather factors. To partially fill this gap, the present study proposes a detailed analysis of more than 2250 isotope data (δ<sup>18</sup>O, δ<sup>2</sup>H, and deuterium excess) related to precipitations collected in the Friuli Venezia Giulia (FVG) region (Italy) with monthly or seasonal frequency in 36 sites between 1984 and 2015.</p><p>The FVG region lies at the north-eastern end of Italy, bordering Austria in the North and Slovenia in the East, and extends over ~7.9·10<sup>3</sup> km<sup>2</sup>. From a hydrogeological point of view, FVG is an interesting case study. Large highly-permeable carbonate aquifers are present in the Alps and Prealps, while the southern part of the region is characterized by an alluvial plain, split by the spring belt into two sectors: the High Plain in the North, characterized by an highly-permeable unconfined aquifer, and the Low Plain in the South, characterized by a system of confined and artesian aquifers. All the aquifers are recharged by the effective precipitations which in the FVG exhibits among the highest annual precipitation rates in Italy (with peaks >3000 mm/year).</p><p>For the present research, the isotopic data were used: (i) to analyze the spatial and seasonal variability of isotopic composition; (ii) to relate water isotopes with orography and weather parameters collected from meteorological stations as well as using ECMWF ERA5 reanalysis; (iii) to reconstruct the local meteoric water lines across the FVG at annual and seasonal bases; (iv) to quantify interannual trends and analyze their spatial distribution; and (iv) to model the spatial distribution of isotope content in precipitation and create annual and seasonal maps.</p>

Past Verses Present; Metamorphosis in Different Spheres of Guwahati: A Study of Srutimala Duara’s Mindprints of Guwahati

2020 ◽  
Vol 8 (2) ◽  
pp. 13
Author(s):  
Ankita Pandey
Keyword(s):  
Point Of View ◽  
Areca Nut ◽  
Medieval Period ◽  
River Bank ◽  
North East India ◽  
North East ◽  
The North ◽  
Indian State ◽  
The City ◽  
Beautiful City

Guwahati derives its name from the Assamese word “Guwa” means areca nut and “Haat” means market. However, the modern Guwahati had been known as the ancient Pragjyotishpura and was the capital of Assam under the Kamrupa kingdom. A beautiful city Guwahati is situated on the south bank of the river Bramhaputra. Moreover, It is known as the largest city in the Indian state of Assam and also the largest metropolis in North East India. It has also its importance as the gateway to the North- East India. Assamese and English are the spoken languages in Guwahati.  In 1667, the Mogul forces were defeated in the battle by the Ahom forces commanded by Lachut Barphukan. Thus, in a sense Guwahati became the bone of contention among the Ahoms, Kochas and the Moguls during the medieval period.  Guwahati the administrative headquarters of Lower Assam with a viceroy or Barbhukan was made by the Ahom king.  Since 1972 it has been the capital of Assam. The present paper will discuss the changes happened in Guwahati over the period of late 1970s till the present time. It will focus on the behavior of people, transformed temples, Panbazar of the city, river bank of Bramhaputra, old Fancy Bazaar, chaotic ways, festivals and seasons including a fifth man made season etc. It will also deal how over the years a city endowed with nature’s gifts and scenic views, has been changing as “a dirty city”. Furthermore, it will also present the insurgencies that have barged into the city. The occurrence of changes will be discussed through the perspective and point of view of Srutimala Duara as presented in her book Mindprints of Guwahati.

THE NORMALIZED DIFFERENCE VEGETATION INDEX AS AN INDICATOR OF DYNAMICS

2021 ◽  
Author(s):  
Haddad Amar ◽  
Beldjazia Amina ◽  
Kadi Zahia ◽  
Redjaimia Lilia ◽  
Rached-Kanouni Malika
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Climatic Factors ◽  
Mediterranean Ecosystems ◽  
Point Of View ◽  
Aleppo Pine ◽  
Landsat 8 ◽  
North East ◽  
The North ◽  
Pine Trees

Mediterranean ecosystems are considered particularly sensitive to climate change. Any change in climatic factors affects the structure and functioning of these ecosystems and has an influence on plant productivity. The main objective of this work is to characterize one of the Mediterranean ecosystems; the Chettaba forest massif (located in the North-East of Algeria) from a vegetation point of view and their link with monthly variations using Landsat 8 satellite images from five different dates (June 25, 2017, July 27, 2017, August 28, 2017, October 15, 2017). The comparison of NDVI values in Aleppo pine trees was performed using analysis of variance and the use of Friedman's non-parametric test. The Mann-Kendall statistical method was applied to the monthly distribution of NDVI values to detect any trends in the data over the study period. The statistical results of NDVI of Aleppo pine trees indicate that the maximum value is recorded in the month of June, while the lowest values are observed in the month of August where the species studied is exposed to periods of thermal stress.

scholarly journals O, H and C isotopic systematics of Icelandic groundwater

2019 ◽  
Vol 98 ◽  
pp. 07031
Author(s):  
Arny E. Sveinbjörnsdóttir ◽  
Andri Stefánsson ◽  
Jan Heinemeier
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopes ◽  
Upper Mantle ◽  
Lower Crust ◽  
Natural Waters ◽  
Large Range ◽  
Carbon Sources ◽  
Water Isotopes ◽  
Stable Water Isotopes ◽  
Range Of Values

Stable water isotopes of oxygen and hydrogen have been studied in Icelandic natural waters since 1960 for hydrological and geothermal research. All the waters are of meteoric and seawater origin. The measured range in δD and δ18O is large -131 to +3.3‰ and -20.8 to +2.3‰ respectively. Some of the waters are more depleted than any present-day precipitation suggesting a pre-Holocene component in the groundwater. Carbon isotopes of streams, rivers, soil and groundwater have been studied since 1990 in order to evaluate the carbon sources and reactions that possibly influence the carbon systematics of the water. Results show large range of values, for δ13CDIC -27.4 to +4.5‰ and for 14CDIC +0.6 to +118 pMC. Apart from atmospheric, organic and rock leaching, input of gas at depth with similar isotopic composition as the pre-erupted melt of the upper mantle and lower crust beneath Iceland have been identified as sources for carbon in the deeper groundwater.

scholarly journals Contrasting stable water isotope signals from convective and large-scale precipitation phases of a heavy precipitation event in southern Italy during HyMeX IOP 13: a modelling perspective

2019 ◽  
Vol 19 (11) ◽  
pp. 7487-7506
Author(s):  
Keun-Ok Lee ◽  
Franziska Aemisegger ◽  
Stephan Pfahl ◽  
Cyrille Flamant ◽  
Jean-Lionel Lacour ◽  
...  
Keyword(s):  
Large Scale ◽  
Cold Front ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Water Isotopes ◽  
Precipitation Event ◽  
Stable Water Isotopes ◽  
Heavy Precipitation Event ◽  
The North ◽  
Upper Level

Abstract. The dynamical context and moisture transport pathways embedded in large-scale flow and associated with a heavy precipitation event (HPE) in southern Italy (SI) are investigated with the help of stable water isotopes (SWIs) based on a purely numerical framework. The event occurred during the Intensive Observation Period (IOP) 13 of the field campaign of the Hydrological Cycle in the Mediterranean Experiment (HyMeX) on 15 and 16 October 2012, and SI experienced intense rainfall of 62.4 mm over 27 h with two precipitation phases during this event. The first one (P1) was induced by convective precipitation ahead of a cold front, while the second one (P2) was mainly associated with precipitation induced by large-scale uplift. The moisture transport and processes responsible for the HPE are analysed using a simulation with the isotope-enabled regional numerical model COSMOiso. The simulation at a horizontal grid spacing of about 7 km over a large domain (about 4300 km ×3500 km) allows the isotopes signal to be distinguished due to local processes or large-scale advection. Backward trajectory analyses based on this simulation show that the air parcels arriving in SI during P1 originate from the North Atlantic and descend within an upper-level trough over the north-western Mediterranean. The descending air parcels reach elevations below 1 km over the sea and bring dry and isotopically depleted air (median δ18O ≤-25 ‰, water vapour mixing ratio q≤2 g kg−1) close to the surface, which induces strong surface evaporation. These air parcels are rapidly enriched in SWIs (δ18O ≥-14 ‰) and moistened (q≥8 g kg−1) over the Tyrrhenian Sea by taking up moisture from surface evaporation and potentially from evaporation of frontal precipitation. Thereafter, the SWI-enriched low-level air masses arriving upstream of SI are convectively pumped to higher altitudes, and the SWI-depleted moisture from higher levels is transported towards the surface within the downdrafts ahead of the cold front over SI, producing a large amount of convective precipitation in SI. Most of the moisture processes (i.e. evaporation, convective mixing) related to the HPE take place during the 18 h before P1 over SI. A period of 4 h later, during the second precipitation phase P2, the air parcels arriving over SI mainly originate from north Africa. The strong cyclonic flow around the eastward-moving upper-level trough induces the advection of a SWI-enriched African moisture plume towards SI and leads to large-scale uplift of the warm air mass along the cold front. This lifts moist and SWI-enriched air (median δ18O ≥-16 ‰, median q≥6 g kg−1) and leads to gradual rain out of the air parcels over Italy. Large-scale ascent in the warm sector ahead of the cold front takes place during the 72 h preceding P2 in SI. This work demonstrates how stable water isotopes can yield additional insights into the variety of thermodynamic mechanisms occurring at the mesoscale and synoptic scale during the formation of a HPE.

scholarly journals Experimental observation of transient <i>δ</i><sup>18</sup>O interaction between snow and advective airflow under various temperature gradient conditions

2017 ◽  
Vol 11 (4) ◽  
pp. 1733-1743 ◽  
Author(s):  
Pirmin Philipp Ebner ◽  
Hans Christian Steen-Larsen ◽  
Barbara Stenni ◽  
Martin Schneebeli ◽  
Aldo Steinfeld
Keyword(s):  
Temperature Gradient ◽  
Isotopic Composition ◽  
Ice Cores ◽  
Transport Processes ◽  
Water Isotopes ◽  
Polar Regions ◽  
Stable Water Isotopes ◽  
Climate History ◽  
Stable Isotopes Of Water ◽  
Past Climate Variability

Abstract. Stable water isotopes (δ18O) obtained from snow and ice samples of polar regions are used to reconstruct past climate variability, but heat and mass transport processes can affect the isotopic composition. Here we present an experimental study on the effect of airflow on the snow isotopic composition through a snow pack in controlled laboratory conditions. The influence of isothermal and controlled temperature gradient conditions on the δ18O content in the snow and interstitial water vapour is elucidated. The observed disequilibrium between snow and vapour isotopes led to the exchange of isotopes between snow and vapour under non-equilibrium processes, significantly changing the δ18O content of the snow. The type of metamorphism of the snow had a significant influence on this process. These findings are pertinent to the interpretation of the records of stable isotopes of water from ice cores. These laboratory measurements suggest that a highly resolved climate history is relevant for the interpretation of the snow isotopic composition in the field.

scholarly journals Central Business District of St. Petersburg 1869–2017

2019 ◽  
Vol 3 (1) ◽  
pp. 23-39
Author(s):  
Константин Аркадьевич Холодилин ◽  
Леонид Эдуардович Лимонов
Keyword(s):  
Spatial Distribution ◽  
Market Economy ◽  
Substantial Reduction ◽  
Central Business District ◽  
Soviet Period ◽  
City Center ◽  
North East ◽  
The North ◽  
Business District ◽  
The City

The city center is at the core of urban and housing economics. Many models crucially depend on it. In a market economy, the location of urban amenities, especially eating establishments, closely correlates with that of the city center and, more generally, with the Central Business District (CBD). In a centrally planned economy, the spatial distribution of those amenities is determined by the central planner and can differ significantly from a market-based distribution. Using the case of St. Petersburg (Russia), we investigate changes in the spatial distribution of eating establishments resulting from the transition from a market economy to a centrally planned one and then again to a market economy. In addition, we explore the shifts of the city center between 1895 and 2017 using eating establishments as a proxy. The spatial distribution is analyzed using a 2-D kernel density estimation. We find evidence for a substantial reduction and dispersion of eating establishments during the Soviet period. We also establish that after the October 1917 Revolution the city center of St. Petersburg moved several kilometers to the north-east.

scholarly journals Experimental observation of transient δ<sup>18</sup>O interaction between snow and advective airflow under various temperature gradient conditions

2017 ◽  
Author(s):  
Pirmin P. Ebner ◽  
Hans Christian Steen-Larsen ◽  
Barbara Stenni ◽  
Martin Schneebeli ◽  
Aldo Steinfeld
Keyword(s):  
Temperature Gradient ◽  
Isotopic Composition ◽  
Ice Cores ◽  
Transport Processes ◽  
Water Isotopes ◽  
Polar Regions ◽  
Stable Water Isotopes ◽  
Equilibrium Processes ◽  
Stable Isotopes Of Water ◽  
Past Climate Variability

Abstract. Stable water isotopes (δ18O) obtained from snow and ice samples of polar regions are used to reconstruct past climate variability, but heat and mass transport processes can affect the isotopic composition. Here we present an experimental study on the effect on the snow isotopic composition by airflow through a snow pack in controlled laboratory conditions. The influence of isothermal and controlled temperature gradient conditions on the δ18O content in the snow and interstitial water vapor is elucidated. The observed disequilibrium between snow and vapor isotopes led to exchange of isotopes between snow and vapor under non-equilibrium processes, significantly changing the δ18O content of the snow. The type of metamorphism of the snow had a significant influence on this process. These findings are pertinent to the interpretation of the records of stable isotopes of water from ice cores. These laboratory measurements suggest that a highly resolved history is relevant for the interpretation of the snow isotopic composition in the field.

Sign in / Sign up

Export Citation Format

Share Document