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PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0261651
Author(s):  
Gabriel J. Bowen ◽  
Jessica S. Guo ◽  
Scott T. Allen

A wide range of hydrological, ecological, environmental, and forensic science applications rely on predictive “isoscape” maps to provide estimates of the hydrogen or oxygen isotopic compositions of environmental water sources. Many water isoscapes have been developed, but few studies have produced isoscapes specifically representing groundwaters. None of these have represented distinct subsurface layers and isotopic variations across them. Here we compiled >6 million well completion records and >27,000 groundwater isotope datapoints to develop a space- and depth-explicit water isoscape for the contiguous United States. This 3-dimensional model shows that vertical isotopic heterogeneity in the subsurface is substantial in some parts of the country and that groundwater isotope delta values often differ from those of coincident precipitation or surface water resources; many of these patterns can be explained by established hydrological and hydrogeological mechanisms. We validate the groundwater isoscape against an independent data set of tap water values and show that the model accurately predicts tap water values in communities known to use groundwater resources. This new approach represents a foundation for further developments and the resulting isoscape should provide improved predictions of water isotope values in systems where groundwater is a known or potential water source.


2021 ◽  
Vol 21 (23) ◽  
pp. 17649-17664
Author(s):  
Yang Yi ◽  
Fan Yi ◽  
Fuchao Liu ◽  
Yunpeng Zhang ◽  
Changming Yu ◽  
...  

Abstract. Mid-level stratiform precipitations during the passage of warm fronts were detailedly observed on two occasions (light and moderate rain) by a 355 nm polarization lidar and water vapor Raman lidar, both equipped with waterproof transparent roof windows. The hours-long precipitation streaks shown in the lidar signal (X) and volume depolarization ratio (δv) reveal some ubiquitous features of the microphysical process of precipitating hydrometeors. We find that for the light-rain case precipitation that reaches the surface begins as ice-phase-dominant hydrometeors that fall out of a shallow liquid cloud layer at altitudes above the 0 ∘C isotherm level, and the depolarization ratio magnitude of falling hydrometeors increases from the liquid-water values (δv<0.09) to the ice/snow values (δv>0.20) during the first 100–200 m of their descent. Subsequently, the falling hydrometeors yield a dense layer with an ice/snow bright band occurring above and a liquid-water bright band occurring below (separated by a lidar dark band) as a result of crossing the 0 ∘C level. The ice/snow bright band might be a manifestation of local hydrometeor accumulation. Most falling raindrops shrink or vanish in the liquid-water bright band due to evaporation, whereas a few large raindrops fall out of the layer. We also find that a prominent δv peak (0.10–0.40) always occurs at an altitude of approximately 0.6 km when precipitation reaches the surface, reflecting the collision–coalescence growth of falling large raindrops and their subsequent spontaneous breakup. The microphysical process (at ice-bright-band altitudes and below) of moderate rain resembles that of the light-rain case, but more large-sized hydrometeors are involved.


Author(s):  
Harmel Obami-Ondon ◽  
Médard Ngouala Mabonzo ◽  
Urbain Gampio Mbilou ◽  
Bernard Mabiala

Abstract. Cette étude porte sur l'impact de la variabilité saisonnière des précipitations sur les eaux du Plateau de Mbé. 120 échantillons d'eau ont été prélevés dans huit (08) points d'eau (1 puits, 4 forages et 3 rivières) entre novembre 2017 et août 2018. L'analysés au laboratoire de ces échantillons, permettent de caractériser les éléments physico-chimiques des eaux. Ces résultats sont traités à partir d'une méthode hydrochimie, en utilisant les diagrammes  : de Piper, de Schoeller Berkaloff, de Stiff, et de Wilcox. Les données traitées montrent que les valeurs obtenues après les analyses des eaux des saisons ne présentent pas une variation considérable et sont toutes conformes aux normes prescrites par l'OMS pour l'eau de boisson, en dehors de la température qui est légèrement supérieure à la normale avec une moyenne de 27 ∘C. Le pH a une moyenne de 5.0; ce qui confirme le caractère acide des eaux dans toute cette zone d'étude. Abstract. This study examines the impact of seasonal rainfall variability on the Mbé Plateau waters. 120 water samples were taken from eight (08) water points (1 well, 4 boreholes and 3 rivers) between November 2017 and August 2018, analyzed in the laboratory, to characterize the physicochemical elements of the water. These results are processed from a hydrochemical method, using the diagrams : of Piper, Schoeller Berkaloff, Stiff, Wilcox. They show that the water values analyzed between the 4 seasons do not vary considerably and all comply with the standards prescribed by the WHO for drinking water, except for the abnormal temperature with an average of 27 ∘C and average pH of 5.0 which confirms the acidity of the waters throughout this study area.


2021 ◽  
Author(s):  
Amin Shoari Nejad ◽  
Andrew C. Parnell ◽  
Alice Greene ◽  
Peter Thorne ◽  
Brian P. Kelleher ◽  
...  

Abstract. We provide an updated sea level dataset for Dublin for the period 1938 to 2016 at yearly resolution. Using a newly collated sea level record for Dublin Port, as well as two nearby tide gauges at Arklow and Howth Harbour, we perform data quality checks and calibration of the Dublin Port record by adjusting the biased high water level measurements that affect the overall calculation of mean sea level (MSL). To correct these MSL values, we use a novel Bayesian linear regression that includes the Mean Low Water values as a predictor in the model. We validate the re-created MSL dataset and show its consistency with other nearby tide gauge datasets. Using our new corrected dataset, we estimate a rate of 1.08 mm/yr sea level rise at Dublin Port between 1953–2016 (95 % CI from 0.62 to 1.55 mm/yr), and a rate of 6.48 mm/yr between 1997–2016 (95 % CI 4.22 to 8.80 mm/yr). Overall sea level rise is in line with expected trends but large multidecadal varaibility has led to higher rates of rise in recent years.


2021 ◽  
Author(s):  
Linn Schäffer ◽  
Arild Helseth ◽  
Magnus Korpås

<div>We present a medium-term hydropower scheduling model that includes state-dependent environmental constraints on maximum discharge. A stochastic dynamic programming algorithm is used to enable modelling of nonconvex relationships in the problem formulation. The model is applied in a case study of a Norwegian hydropower system with multiple reservoirs. We find that the maximum discharge constraint significantly impacts the water values and simulated operation of the hydropower system. A main finding is that the nonconvex characteristics of the environmental constraint is reflected in the water values, implying a nonconvex objective function. Operation according to the computed water values is simulated for cases with and without the environmental constraint. Even though operation of the system changes considerably when the environmental constraint is included, the total electricity generation over the year is kept constant, and the total loss in expected profit limited to less than 0.8%.</div>


2021 ◽  
Author(s):  
Linn Schäffer ◽  
Arild Helseth ◽  
Magnus Korpås

<div>We present a medium-term hydropower scheduling model that includes state-dependent environmental constraints on maximum discharge. A stochastic dynamic programming algorithm is used to enable modelling of nonconvex relationships in the problem formulation. The model is applied in a case study of a Norwegian hydropower system with multiple reservoirs. We find that the maximum discharge constraint significantly impacts the water values and simulated operation of the hydropower system. A main finding is that the nonconvex characteristics of the environmental constraint is reflected in the water values, implying a nonconvex objective function. Operation according to the computed water values is simulated for cases with and without the environmental constraint. Even though operation of the system changes considerably when the environmental constraint is included, the total electricity generation over the year is kept constant, and the total loss in expected profit limited to less than 0.8%.</div>


2021 ◽  
Vol 13 (15) ◽  
pp. 2960
Author(s):  
Andrzej Araszkiewicz ◽  
Damian Kiliszek ◽  
Michał Mierzwiak ◽  
Joanna Nowak Da Costa ◽  
Marcin Szołucha

An increase in temperature causes higher evaporation of water from water bodies; consequently, the water content in the atmosphere also increases. The precipitable water (PW), as the water content in the atmospheric air column, is therefore an important parameter to consider when studying climate change. The aim of this study was to analyse multi-annual precipitable water data derived from a dense Global Navigational Satellite Systems (GNSS) network. Twelve years of observations from over a hundred ASG-EUPOS stations were used to estimate changes in precipitation water values over Poland. The data were validated by comparison with the available radio-sounding data. The analysis of the GPS-based PW values showed an upward trend in the PW value of 0.078 mm/year. The spatio-temporal distribution of the mean PW values and their fluctuations over the years were studied and visualised in the form of maps. The results are congruent with the fact that Poland lies on the border of influence of both continental and oceanic climates. Our results are also consistent with other climate research concerning this region.


Irriga ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 367-382
Author(s):  
Marcello Henryque Costa Souza ◽  
Roberta Daniela da Silva Santos ◽  
Clóvis Manoel Carvalho Ramos ◽  
Luís Henrique Bassoi

ESTIMATIVA DA DEMANDA HÍDRICA DE DIFERENTES CULTURAS NO PERÍMETRO IRRIGADO PONTAL SUL     MARCELLO HENRYQUE COSTA DE SOUZA1; ROBERTA DANIELA DA SILVA SANTOS2; CLOVIS MANOEL CARVALHO RAMOS3 E LUÍS HENRIQUE BASSOI4   1 Setor de Operação do Sistema, Distrito de Irrigação Nilo Coelho – DINC, Vila CS-1, Perímetro Senador Nilo Coelho s/n. CEP: 56.300-990. Petrolina-PE, Brasil, [email protected]; 2 Instituto Federal de Educação, Ciência e Tecnologia de Roraima – IFRR, campus Novo Paraiso, BR-174, s/n - Vila Novo Paraíso, Caracaraí – RR. CEP:69365-000, Brasil, [email protected]; 3 Colegiado de Engenharia Agrícola e Ambiental, UNIVASF, Avenida Antônio Carlos Magalhães, 510 - Santo Antônio. CEP: 48902-300 – Juazeiro – BA, [email protected]; 4 Embrapa Instrumentação, R. 15 de Novembro, 1452 - Centro, São Carlos – SP. CEP:13560-970, Brasil. [email protected].     1 RESUMO   O presente trabalho objetivou determinar a demanda hídrica para diferentes culturas no Perímetro Irrigado Pontal Sul e verificar se a lâmina fornecida é capaz de atender ou não as necessidades das culturas; identificar quando e qual cenário há maior necessidade de água; e definir quais cenários baseados em diferentes culturas e na disponibilidade de água poderão ser atendidos de acordo com a capacidade de bombeamento do perímetro irrigado. Para alcançar tais objetivos foram feitos levantamentos de dados, estudos bibliográficos, geração de cenários agrícolas (considerando diferentes culturas – Acerola, Caju, Goiaba, Banana, Coco, Uva e Manga) e estimativa das demandas do Perímetro Irrigado Pontal Sul. De acordo com os cenários gerados, o perímetro irrigado apresenta, em parte, dados que favorecem a superestimação de valores de água a serem fornecidos, porém também apresenta problemas no que diz respeito ao fornecimento de água para as culturas quando avaliados cenários e condições de exigência máxima das culturas. Assim, este estudo mostra a necessidade do estudo prévio e uma alternativa para um planejamento adequado para implantação das culturas e uso de sistemas de irrigação no Perímetro Irrigado Pontal Sul.   Palavras-chave: irrigação, planejamento agrícola, uso de água.     SOUZA, M. H. C.; SANTOS, R. D. S.; RAMOS, C. M. C.; BASSOI, L. H. ESTIMATION OF WATER DEMAND BY CROPS FOR WATER ALLOCATION IN PONTAL SUL IRRIGATION SCHEME     2 ABSTRACT   This work aimed to determine the water demand for different crops in the Pontal Sul Irrigation Scheme and to verify if the water depth supplied is capable of attending crop water demands; to identify when and which scenario the water demand is maximum; and to define which scenarios based on different crops and on water availability can be met according to the pumping capacity of the irrigation scheme. To achieve these objectives, data surveys, bibliographic studies, generation of agricultural scenarios (considering different cultures - Barbados cherry, Cashew, Guava, Banana, Coconut, Grape and Mango) and estimation of the demands of the Pontal Sul Irrigated Perimeter were made. According to the scenarios generated, the Pontal Sul irrigated project presents, in part, data that favor the overestimation of water values ​​to be provided, but it also presents problems related to water supply for crops in scenarios and conditions of maximum crop requirements. Thus, this study shows the need for a previous study and an alternative for planning for cropping and the use of irrigation systems in Pontal Sul Irrigation Scheme.   Keywords: irrigation, agricultural planning, water use.


2021 ◽  
Vol 70 (1-2) ◽  
pp. 67-75
Author(s):  
Polina Lemenkova

Summary The study presents a comparative analysis of eight Vegetation Indices (VIs) used to examine vegetation greenness over the northern coasts of Iceland. The geographical extent of the study area is set by the coordinates of the two fjords, Eyjafjörður and Skagafjörður, notable for their agricultural significance. Vegetation in Iceland is fragile due to the harsh climate, climate change, overgrazing and volcanic activity, which increase soil erosion. The study was conducted on a Landsat TM image using SAGA GIS as a technical tool for raster bands calculations. The NDVI dataset shows a range from -0.56 to 0.24, with 0 indicating ‘no vegetation’, and negative values – ‘other surfaces’ (e.g. rocks, open terrain). The DVI, compared to the NDVI, shows statistically non-normalized values ranging from -112 to 0, with extreme negative values while the coastal vegetation areas are badly distinguished from the water areas. The NRVI shows an extent from -0.24 to 0.48 with higher values for vegetation. The NRVI reduces topographic, solar and atmospheric effects and creates a normal data distribution. RVI shows a range in a dataset from 0.2 to 3.2 with vegetation in the river valleys clearly visible and depicted, while the water areas have values 0.8 to 1.0. The CTVI shows corrected TVI, in a data range -0.10 to 1.10, as the dataset of NDVI were negative. The TVI dataset ranges from 0.44 to 0.80 with the ice-covered areas and glaciers distinguishable and water values within a range from 0.60 to 0.64 and the vegetation from 0.60 to 0.44. The TTVI dataset ranges from 0.40 to 0.80 performing similarly to the TVI, but more refined with vegetation values 0.64 to 0.68. SAVI dataset ranges from -0.80 to 0.30 with minimized effects of soil on the vegetation through a constant soil adjustment factor added into the NDVI formula. The paper presents a comparison of eight VIs for Arctic vegetation monitoring. The overall behavior of SAGA GIS in calculation and mapping of the VIs is effective in terms of their use for vegetation mapping of the region.


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