scholarly journals Evaporation in Hydrological Models Under Rising CO2: A Jump into The Unknown

2021 ◽  
Author(s):  
Thibault Lemaitre-Basset ◽  
Ludovic OUDIN ◽  
Guillaume THIREL
Keyword(s):  
Stomatal Resistance ◽  
Limited Area ◽  
Climate Projections ◽  
Hydrological Models ◽  
The North ◽  
Rapid Changes ◽  
Runoff Decrease ◽  
Rcp 8.5 ◽  
Atmospheric Concentrations ◽  
Different Levels

Abstract Many hydrological models use the concept of potential evaporation (PE) to simulate actual evaporation. PE formulations often neglect the effect of carbon dioxide (CO2), which challenges their relevance in a context of climate change and rapid changes in CO2 atmospheric concentrations. In this work, we implement three options from the literature to take into account the effect of CO2 on stomatal resistance in the well-known Penman–Monteith PE formulation. We assess their impact on future runoff using the Budyko framework over France. On the basis of an ensemble of Euro-Cordex climate projections using the RCP 4.5 and RCP 8.5 scenarios, we show that taking into account CO2 in PE formulations largely reduces PE values but also limits projections of runoff decrease, especially under an emissive scenario, namely, the RCP 8.5. Whereas the classic Penman–Monteith formulation yields decreasing runoff projections over most of France, taking into account CO2 yields more contrasting results. Runoff increase becomes likely in the north of France, which is an energy-limited area, with different levels of runoff response produced by the three tested formulations. The results highlight the sensitivity of hydrological projections to the processes represented in the PE formulation.

scholarly journals Dynamical Downscaling of ERA5 Data on the North-Western Mediterranean Sea: From Atmosphere to High-Resolution Coastal Wave Climate

2021 ◽  
Vol 9 (2) ◽  
pp. 208
Author(s):  
Valentina Vannucchi ◽  
Stefano Taddei ◽  
Valerio Capecchi ◽  
Michele Bendoni ◽  
Carlo Brandini
Keyword(s):  
Mediterranean Sea ◽  
Wind Wave ◽  
Dynamical Downscaling ◽  
Wave Climate ◽  
Western Mediterranean ◽  
Limited Area ◽  
Computational Domain ◽  
Wave Hindcast ◽  
The North ◽  
Western Mediterranean Sea

A 29-year wind/wave hindcast is produced over the Mediterranean Sea for the period 1990–2018. The dataset is obtained by downscaling the ERA5 global atmospheric reanalyses, which provide the initial and boundary conditions for a numerical chain based on limited-area weather and wave models: the BOLAM, MOLOCH and WaveWatch III (WW3) models. In the WW3 computational domain, an unstructured mesh is used. The variable resolutions reach up to 500 m along the coasts of the Ligurian and Tyrrhenian seas (Italy), the main objects of the study. The wind/wave hindcast is validated using observations from coastal weather stations and buoys. The wind validation provides velocity correlations between 0.45 and 0.76, while significant wave height correlations are much higher—between 0.89 and 0.96. The results are also compared to the original low-resolution ERA5 dataset, based on assimilated models. The comparison shows that the downscaling improves the hindcast reliability, particularly in the coastal regions, and especially with regard to wind and wave directions.

Agriculture expansion and deforestation in seasonally dry forests of north-west Argentina

2005 ◽  
Vol 32 (2) ◽  
pp. 140-148 ◽  
Author(s):  
H. RICARDO GRAU ◽  
N. IGNACIO GASPARRI ◽  
T. MITCHELL AIDE
Keyword(s):  
Global Trends ◽  
North West ◽  
Conservation Policies ◽  
Seasonally Dry ◽  
The North ◽  
Agriculture Expansion ◽  
Soybean Price ◽  
Different Levels ◽  
Semi Arid ◽  
Arid Chaco

In Argentina, deforestation due to agriculture expansion is threatening the Semi-arid Chaco, one of the largest forested biomes of South America. This study focuses on the north-west boundary of the Argentine Semi-arid Chaco, where soybean is the most important crop. Deforestation was estimated for areas with different levels of soil and rainfall limitation for agriculture between 1972 and 2001, with a finer analysis in three periods starting in 1984, which are characterized by differences in rainfall, soybean price, production cost, technology-driven yield and national gross domestic product. Between 1972 and 2001, 588 900 ha (c. 20% of the forests) were deforested. Deforestation has been accelerating, reaching >28 000 ha yr−1 after 1997. The initial deforestation was associated with black bean cultivation following an increase in rainfall during the 1970s. In the 1980s, high soybean prices stimulated further deforestation. Finally, the introduction of soybean transgenic cultivars in 1997 reduced plantation costs and stimulated a further increase in deforestation. The domestic economy had little association with deforestation. Although deforestation was more intense in the moister (rainfall >600 mm yr−1) areas, more than 300 000 ha have already been deforested in the drier areas, suggesting that climatic limitations are being overcome by technological and genetic improvement. Furthermore, more than 300 000 ha of forest occur in sectors without major soil and rainfall limitations. If global trends of technology, soybean markets and climate continue, and no active conservation policies are applied, vast areas of the Chaco will be deforested in the coming decades.

Boys' circumcision and girls' puberty rites among the Swahili of Mafia Island, Tanzania

Africa ◽  
1976 ◽  
Vol 46 (1) ◽  
pp. 21-33 ◽  
Author(s):  
A. P. Caplan
Keyword(s):  
The Political ◽  
The North ◽  
Political Implications ◽  
Opening Paragraph ◽  
Different Levels

Opening ParagraphIn the north of Mafia Island, the rites surrounding the circumcision of boys and the first menstruation of girls are no longer, if indeed they ever were, universally performed. This article attempts to explain this situation, and in so doing, draws on some of Turner's work on symbolism. In particular, his distinction between different levels of meaning expressed by symbols—the exegetical, the operational and the positional (1962)—is followed in a discussion of the political implications of performance or rejection of the rites.

Increased frequency of Eurasian double jets linked to summer heat extremes in Europe

2021 ◽  
Author(s):  
Efi Rousi ◽  
Kai Kornhuber ◽  
Goratz Beobide Arsuaga ◽  
Fei Luo ◽  
Dim Coumou
Keyword(s):  
Zonal Wind ◽  
Large Scale ◽  
Driving Forces ◽  
Linear Regression Analysis ◽  
Reanalysis Data ◽  
Self Organizing Maps ◽  
Upper Troposphere ◽  
The North ◽  
Heat Extremes ◽  
Different Levels

<p>Persistent summer extremes, such as heatwaves and droughts, can have considerable impacts on nature and societies. There is evidence that weather persistence has increased in Europe over the past decades, in association to changes in atmosphere dynamics, but uncertainties remain and the driving forces are not yet well understood. </p><p>Particularly for Europe, the jet stream may affect surface weather significantly by modulating the North Atlantic storm tracks. Here, we examine the hypothesis that high-latitude warming and decreased westerlies in summer result in more double jets, consisting of two distinct maxima of the zonal wind in the upper troposphere, over the Eurasian sector. Previous work has shown that such double jet states are related to persistent blocking-like circulation in the mid-latitudes. </p><p>We adapt a dynamical perspective of heat extreme trends by looking at large scale circulation and in particular, changes in the zonal mean zonal wind in different levels of the upper troposphere. We define clusters of jet states with the use of Self-Organizing Maps and analyze their characteristics. We find an increase in frequency and persistence of a cluster of double jet states for the period 1979-2019 during July-August (in ERA5 reanalysis data). Those states are linked to increased surface temperature and more frequent heatwaves compared to climatology over western, central, and northern Europe. Significant positive double jet anomalies are found to be dominant in the days preceding and/or coinciding with some of the most intense historical heatwaves in Europe, such as those of 2003 and 2018. A linear regression analysis shows that the increase in frequency and persistence of double jet states may explain part of the strong upward trend in heat extremes over these European regions.</p>

scholarly journals Convergence of the Pamir and the South Tian Shan in the late Cenozoic: Insights from provenance analysis in the Wuheshalu section at the convergence area

Lithosphere ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 507-523 ◽  
Author(s):  
Xinwei Chen ◽  
Hanlin Chen ◽  
Edward R. Sobel ◽  
Xiubin Lin ◽  
Xiaogan Cheng ◽  
...  
Keyword(s):  
Source Area ◽  
Limited Area ◽  
Late Cenozoic ◽  
Provenance Analysis ◽  
The South ◽  
Active Deformation ◽  
The North ◽  
Large Populations ◽  
A Minor ◽  
Tian Shan

Abstract In response to collision and convergence between India and Asia during the Cenozoic, convergence took place between the Pamir and South Tian Shan. Here we present new detrital zircon U-Pb ages coupled with conglomerate clast counting and sedimentary data from the late Cenozoic Wuheshalu section in the convergence zone, to shed light on the convergence process of the Pamir and South Tian Shan. Large Triassic zircon U-Pb age populations in all seven samples suggest that Triassic igneous rocks from the North Pamir were the major source area for the late Cenozoic Wuheshalu section. In the Miocene, large populations of the North Pamir component supports rapid exhumation in the North Pamir and suggest that topography already existed there since the early Miocene. Exhumation of the South Tian Shan was relatively less important in the Miocene and its detritus could only reach a limited area in the foreland area. Gradually increasing sediment loading and convergence of the Pamir and South Tian Shan caused rapid subsidence in the convergence area. Since ca. 6–5.3 Ma, the combination of a major North Pamir component and a minor South Tian Shan component at the Wuheshalu section is consistent with active deformation of the South Tian Shan and the North Pamir. During deposition of the upper Atushi Formation, a larger proportion of North Pamir–derived sediments was deposited in the Wuheshalu section, maybe because faulting and northward propagation of the North Pamir caused northward displacement of the depocenter to north of the Wuheshalu section.

scholarly journals Impacts of the North Atlantic Warming Hole in Future Climate Projections: Mean Atmospheric Circulation and the North Atlantic Jet

2019 ◽  
Vol 32 (10) ◽  
pp. 2673-2689 ◽  
Author(s):  
Melissa Gervais ◽  
Jeffrey Shaman ◽  
Yochanan Kushnir
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Forced Response ◽  
Future Climate ◽  
Climate Projections ◽  
Transient Eddy ◽  
The North ◽  
Climate Simulations ◽  
The North Atlantic ◽  
The Impact

Abstract In future climate simulations there is a pronounced region of reduced warming in the subpolar gyre of the North Atlantic Ocean known as the North Atlantic warming hole (NAWH). This study investigates the impact of the North Atlantic warming hole on atmospheric circulation and midlatitude jets within the Community Earth System Model (CESM). A series of large-ensemble atmospheric model experiments with prescribed sea surface temperature (SST) and sea ice are conducted, in which the warming hole is either filled or deepened. Two mechanisms through which the NAWH impacts the atmosphere are identified: a linear response characterized by a shallow atmospheric cooling and increase in sea level pressure shifted slightly downstream of the SST changes, and a transient eddy forced response whereby the enhanced SST gradient produced by the NAWH leads to increased transient eddy activity that propagates vertically and enhances the midlatitude jet. The relative contributions of these two mechanisms and the details of the response are strongly dependent on the season, time period, and warming hole strength. Our results indicate that the NAWH plays an important role in midlatitude atmospheric circulation changes in CESM future climate simulations.

scholarly journals FeelOpo

2018 ◽  
Vol 9 (2) ◽  
pp. 52-62
Author(s):  
Isabel Carvalho ◽  
José Bidarra ◽  
Carla Porto
Keyword(s):  
Cultural Identity ◽  
Interactive Art ◽  
Interactive Installation ◽  
Art Installation ◽  
The North ◽  
Intangible Heritage ◽  
Identity Based ◽  
Different Levels

FeelOpo is an interactive art installation that allows contact with fragments of the immaterial heritage of the Oporto City in the North of Portugal. Through location-based storytelling of the living city, this interactive installation allows visitors to explore, at different levels, several typical characteristics of this city, addressing aspects of cultural identity based on contrasting images and videos. The visitors feel and explore visual stories of the live city, through a process of appropriation and articulation of these narratives, generating an expansion of this intangible heritage.

scholarly journals Surface Heat Budget over the North Sea in Climate Change Simulations

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 272 ◽  
Author(s):  
Christian Dieterich ◽  
Shiyu Wang ◽  
Semjon Schimanke ◽  
Matthias Gröger ◽  
Birgit Klein ◽  
...  
Keyword(s):  
Climate Change ◽  
Heat Flux ◽  
North Sea ◽  
Heat Budget ◽  
Coupled Model ◽  
Surface Heat ◽  
The North ◽  
The North Sea ◽  
Rcp 8.5 ◽  
Surface Heat Budget

An ensemble of regional climate change scenarios for the North Sea is validated and analyzed. Five Coupled Model Intercomparison Project Phase 5 (CMIP5) General Circulation Models (GCMs) using three different Representative Concentration Pathways (RCPs) have been downscaled with the coupled atmosphere–ice–ocean model RCA4-NEMO. Validation of sea surface temperature (SST) against different datasets suggests that the model results are well within the spread of observational datasets. The ensemble mean SST with a bias of less than 1 ∘ C is the solution that fits the observations best and underlines the importance of ensemble modeling. The exchange of momentum, heat, and freshwater between atmosphere and ocean in the regional, coupled model compares well with available datasets. The climatological seasonal cycles of these fluxes are within the 95% confidence limits of the datasets. Towards the end of the 21st century the projected North Sea SST increases by 1.5 ∘ C (RCP 2.6), 2 ∘ C (RCP 4.5), and 4 ∘ C (RCP 8.5), respectively. Under this change the North Sea develops a specific pattern of the climate change signal for the air–sea temperature difference and latent heat flux in the RCP 4.5 and 8.5 scenarios. In the RCP 8.5 scenario the amplitude of the spatial heat flux anomaly increases to 5 W/m 2 at the end of the century. Different hypotheses are discussed that could contribute to the spatially non-uniform change in air–sea interaction. The most likely cause for an increased latent heat loss in the central western North Sea is a drier atmosphere towards the end of the century. Drier air in the lee of the British Isles affects the balance of the surface heat budget of the North Sea. This effect is an example of how regional characteristics modulate global climate change. For climate change projections on regional scales it is important to resolve processes and feedbacks at regional scales.

scholarly journals Improving Meteorological Seasonal Forecasts for Hydrological Modeling in European Winter

2020 ◽  
Vol 59 (2) ◽  
pp. 317-332
Author(s):  
Nicky Stringer ◽  
Jeff Knight ◽  
Hazel Thornton
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Hydrological Modeling ◽  
Strongly Correlated ◽  
Hydrological Models ◽  
Seasonal Forecasts ◽  
The North ◽  
Ensemble Mean ◽  
The North Atlantic Oscillation ◽  
Correlation Skill

AbstractRecent advances in the skill of seasonal forecasts in the extratropics during winter mean they could offer improvements to seasonal hydrological forecasts. However, the signal-to-noise paradox, whereby the variability in the ensemble mean signal is lower than would be expected given its correlation skill, prevents their use to force hydrological models directly. We describe a postprocessing method to adjust for this problem, increasing the size of the predicted signal in the large-scale circulation. This reduces the ratio of predictable components in the North Atlantic Oscillation (NAO) from 3 to 1. We then derive a large ensemble of daily sequences of spatially gridded rainfall that are consistent with the seasonal mean NAO prediction by selecting historical observations conditioned on the adjusted NAO forecasts. Over northern and southwestern Europe, where the NAO is strongly correlated with winter mean rainfall, the variability of the predicted signal in the adjusted rainfall forecasts is consistent with the correlation skill (they have a ratio of predictable components of ~1) and are as skillful as the unadjusted forecasts. The adjusted forecasts show larger predicted deviations from climatology and can be used to better assess the risk of extreme seasonal mean precipitation as well as to force hydrological models.

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