Estimating Sensible and Latent Heat Fluxes over an Inland Water Body Using Optical and Microwave Scintillometers     

Pierre  Adrien  Isabelle  Pierre-Erik  Nadeau  Daniel F.  Thiboult  Antoine  Perelet  Alexei  Rousseau  Alain N.  Anctil  François  Deschamps  Jaril 《Boundary-Layer Meteorology》2022,185(2):277-308

Boundary-Layer Meteorology - Observations of turbulent heat fluxes over inland water bodies are scarce despite being critical to adequate lake parametrization for numerical weather forecast and...  相似文献   

Reply to “Comment on ‘Attenuation, source parameters and site effects in the Irpinia–Basilicata region (southern Apennines, Italy)’ by I.B. Morozov”     

Luciana Cantore  Adrien Oth  Stefano Parolai  Dino Bindi 《Journal of Seismology》2012,16(1):91-93

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Demarcation of fluoride vulnerability zones in granitic aquifer,semi-arid region,Telengana, India     

Ankita Chatterjee  Sarah Sarah  Pagodala Damodaram Sreedevi  Adrien Selles  Shakeel Ahmed 《Arabian Journal of Geosciences》2017,10(24):558

This study has been carried out in the granitic aquifer of Maheshwaram watershed, Telengana, India. In this study, groundwater sample data of 8 years were analyzed for the fluoride content with other chemical quality parameters. The correlation and factor analysis were employed to understand the mechanisms for fluoride (F) enrichment as well as the hydrochemistry of the area. These analyses addressed that the observed groundwater quality was due to water-rock interaction in the aquifer and fluoride is coming from the dissolution of fluorite and other silicate minerals like biotite and hornblende by the groundwater. Land use/land cover (LULC) study from 2002 to 2008 revealed there were significant positive changes in build-up land and negative changes in vegetation cover after 2003. The main agriculture (paddy) has been reduced to 0.97 km² in 2008 from 2.39 km² in 2003. The studied watershed has been characterized on the basis of F concentration into safe, transition, and unsafe groups following the WHO and BIS guidelines. The temporal variation of the three groups showed that 57.6% area of the watershed was in unsafe zone in 2000–2003, but 69.2% of the area became safe in 2006–2009. It has been found that F concentration reduced in 12.59% of the area (became safe from unsafe) accompanied by the reduction of paddy field area. After validation with present (2016) fluoride concentrations, it was found that 16.28% are vulnerable in near future. The results of this study showed that (a) the safe and unsafe zones of fluoride concentrations vary with time with the changes in other parameters associated with it like crop pattern and (b) vulnerable zone can be identified based on the susceptibility to change of safe and unsafe zones. Such studies are useful for planning and management purposes.  相似文献   

Hydraulic visibility: Using satellite altimetry to parameterize a hydraulic model of an ungauged reach of a braided river          下载免费PDF全文

Pierre‐André Garambois  Stéphane Calmant  Hélène Roux  Adrien Paris  Jérôme Monnier  Pascal Finaud‐Guyot  Amanda Samine Montazem  Joecila Santos da Silva 《水文研究》2017,31(4):756-767

What hydraulic information can be gained from remotely sensed observations of a river's surface? In this study, we analyze the relationship between river bed undulations and water surfaces for an ungauged reach of the Xingu River, a first‐order tributary of the Amazon river. This braided reach is crosscut more than 10 times by a ENVISAT (ENVironmental SATellite) track that extends over 100 km. Rating curves based on a modeled discharge series and altimetric measurements are used, including the zero‐flow depth Z ₀ parameter, which describes river's bathymetry. River widths are determined from JERS (Japanese Earth Ressources Satellite) images. Hydrodynamic laws predict that irregularities in the geometry of a river bed produce spatial and temporal variations in the water level, as well as in its slope. Observation of these changes is a goal of the Surface Water and Ocean Topography satellite mission, which has a final objective of determining river discharge. First, the concept of hydraulic visibility is introduced, and the seasonality of water surface slope is highlighted along with different flow regimes and reach behaviors. Then, we propose a new single‐thread effective hydraulic approach for modeling braided rivers flows, based on the observation scales of current satellite altimetry. The effective hydraulic model is able to reproduce water surface elevations derived by satellite altimetry, and it shows that hydrodynamical signatures are more visible in areas where the river bed morphology varies significantly and for reaches with strong downstream control. The results of this study suggest that longitudinal variations of the slope might be an interesting criteria for the analysis of river segmentation into elementary reaches for the Surface Water Ocean Topography mission that will provide continuous measurements of the water surface elevations, the slopes, and the reach widths.  相似文献   

The electrical conductivity of olivine under highly reducing conditions     

L. P. Lemelle  A. G. Duba  F. Guyot 《Physics and Chemistry of Minerals》1998,26(2):164-170

The electrical conductivity of San Carlos olivine has been measured at 1100 °C under reducing conditions at controlled oxygen fugacity, inside and outside the olivine stability field, in order to study the kinetics of olivine destabilization. Electrical conductivity increases along the direction [010] and decreases along [001]. as oxygen fugacity decreases. To understand these dependences, electrical conductivity transitory regimes were studied. In response to decreases in oxygen fugacity, two transient regimes with different time scales have been observed. A fast (≈1–2 min) increase of electrical conductivity is first observed, followed by a slower decrease (1–10 h, depending on the crystal orientation). After a few hours of annealing, precipitation of metallic iron and nickel and formation of amorphous silica can be observed at the crystal surface. The fast conductivity increase in the first transient regime is ascribed to an increase in the population of electrons at the olivine surface. Two effects: (1) equilibration of surface defects with the bulk of the crystal, and (2) iron loss from the olivine due to metal precipitation, could explain the subsequent decrease of electrical conductivity. Anisotropic diffusion of surface defects to the bulk of the crystal, by a process faster than atomic diffusion is the most likely. Received: 3 September 1997 / Revised, accepted: 16 April 1998  相似文献   

Trends in rainfall and temperature in the Peruvian Amazon–Andes basin over the last 40 years (1965–2007)     

Waldo Sven Lavado Casimiro  David Labat  Josyane Ronchail  Jhan Carlo Espinoza  Jean Loup Guyot 《水文研究》2013,27(20):2944-2957

The hydroclimatology of the Peruvian Amazon–Andes basin (PAB) which surface corresponding to 7% of the Amazon basin is still poorly documented. We propose here an extended and original analysis of the temporal evolution of monthly rainfall, mean temperature (T_mean), maximum temperature (T_max) and minimum temperature (T_min) time series over two PABs (Huallaga and Ucayali) over the last 40 years. This analysis is based on a new and more complete database that includes 77 weather stations over the 1965–2007 period, and we focus our attention on both annual and seasonal meteorological time series. A positive significant trend in mean temperature of 0.09 °C per decade is detected over the region with similar values in the Andes and rainforest when considering average data. However, a high percentage of stations with significant T_mean positive trends are located over the Andes region. Finally, changes in the mean values occurred earlier in T_max (during the 1970s) than in T_min (during the 1980s). In the PAB, there is neither trend nor mean change in rainfall during the 1965–2007 period. However, annual, summer and autumn rainfall in the southern Andes presents an important interannual variability that is associated with the sea surface temperature in the tropical Atlantic Ocean while there are limited relationships between rainfall and El Niño‐Southern Oscillation (ENSO) events. On the contrary, the interannual temperature variability is mainly related to ENSO events. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Cl and Na Fluxes in an Andean Foreland Basin of the Peruvian Amazon: An Anthropogenic Impact Evidence     

Jean-Sébastien Moquet  Laurence Maurice  Alain Crave  Jérôme Viers  Nore Arevalo  Christelle Lagane  Waldo Lavado-Casimiro  Jean-Loup Guyot 《Aquatic Geochemistry》2014,20(6):613-637

The dissolved load of the Amazon River is generally considered to be lowly impacted by anthropogenic activities. In this work, based on the chemical and hydrological database of the Environmental Research Observatory—HYBAM (http://www.ore-hybam.org), we explore the importance of the Peruvian Foreland petroleum activity on the dissolved Na and Cl fluxes of the Amazon River. The main result of this study allows us suggesting that oil extraction activity, concentrated in the El Tigre River basin, a small foreland watershed in the Peruvian Amazon, influenced drastically the Na and Cl exportation of the Amazon River during the 2006–2007 period. During these years,  the dissolved exportations of this basin represented almost 20 % of the annual dissolved Cl Amazon flux and almost 12 % of the annual dissolved Na Amazon flux for a mean annual discharge <1 % of the Amazon River discharge. Since the last decades, the anthropogenic activities are increasing over the whole Amazon basin, especially in Andean countries. In this context, our results demonstrate that extractive activity cannot be considered as negligible on the hydro-chemistry of the Amazonian Rivers especially for the weathering budget estimation based on river-dissolved loads. Moreover, Cl and Na can be used to trace the formation waters derived from oil extraction at a large spatial scale. The environmental impacts of contaminants associated with deep water released to the hydrosystem (polycyclic aromatics hydrocarbons, metallic trace elements, etc.) at local and regional scales are still underestimated and should be monitored to map their local and regional influence and to prevent their risks on human health.  相似文献   

The Planck High Frequency Instrument, a third generation CMB experiment, and a full sky submillimeter survey     

J. M. Lamarre  J. L. Puget  F. Bouchet  P. A. R. Ade  A. Benoit  J. P. Bernard  J. Bock  P. De Bernardis  J. Charra  F. Couchot  J. Delabrouille  G. Efstathiou  M. Giard  G. Guyot  A. Lange  B. Maffei  A. Murphy  F. Pajot  M. Piat  I. Ristorcelli  D. Santos  R. Sudiwala  J. F. Sygnet  J. P. Torre  V. Yurchenko  D. Yvon 《New Astronomy Reviews》2003,47(11-12):1017

The High Frequency Instrument (HFI) of Planck is the most sensitive CMB experiment ever planned. Statistical fluctuations (photon noise) of the CMB itself will be the major limitation to the sensitivity of the CMB channels. Higher frequency channels will measure galactic foregrounds. Together with the Low Frequency Instrument, this will make a unique tool to measure the full sky and to separate the various components of its spectrum. Measurement of the polarization of these various components will give a new picture of the CMB. In addition, HFI will provide the scientific community with new full sky maps of intensity and polarization at six frequencies, with unprecedented angular resolution and sensitivity. This paper describes the logics that prevailed to define the HFI and the performances expected from this instrument. It details several features of the HFI design that has not been published up to now.  相似文献   

Marginal abatement cost curves and the quality of emission reductions: a case study on Brazil     

Adrien Vogt-Schilb  Stéphane Hallegatte  Christophe de Gouvello 《Climate Policy》2013,13(6):703-723

Decision makers facing emission-reduction targets need to decide which abatement measures to implement, and in which order. This article investigates how marginal abatement cost (MAC) curves can inform such a decision. We re-analyse a MAC curve built for Brazil by 2030, and show that misinterpreting MAC curves as abatement supply curves can lead to suboptimal strategies. It would lead to (1) under-investment in expensive, long-to-implement and large-potential options, such as clean transportation infrastructure, and (2) over-investment in cheap but limited-potential options such as energy-efficiency improvement in refineries. To mitigate this issue, the article proposes a new graphical representation of MAC curves that explicitly renders the time required to implement each measure.

Policy relevance

In addition to the cost and potential of available options, designing optimal short-term policies requires information on long-term targets (e.g. halving emissions by 2050) and on the speed at which measures can deliver emission reductions. Mitigation policies are thus best investigated in a dynamic framework, building on sector-scale pathways to long-term targets. Climate policies should seek both quantity and quality of abatement, by combining two approaches: a ‘synergy approach’ that focuses on the cheapest mitigation options and maximizes co-benefits, and an ‘urgency approach’ that starts from a long-term objective and works backward to identify actions that need to be implemented early. Accordingly, sector-specific policies may be used (1) to remove implementation barriers on negative- and low-cost options and (2) to ensure short-term targets are met with abatement of sufficient quality. Indeed, such policies can avoid under-investment in the long-to-implement options required to reach long-term targets, which are otherwise difficult to enforce.  相似文献   

Sediment production and transport from in situ-produced cosmogenic 10Be and river loads in the Napo River basin,an upper Amazon tributary of Ecuador and Peru   总被引：1，自引：0，他引：1  

H. Wittmann  F. von Blanckenburg  J.L. Guyot  A. Laraque  C. Bernal  P.W. Kubik 《Journal of South American Earth Sciences》2011,31(1):45-53

Cosmogenic nuclide-based denudation rates and published erosion rates from recent river gauging in the Napo River basin (Peruvian Amazonia) are used to decipher erosion and sedimentation processes along a 600 km long transect from the headwaters to the lowlands. The sediment-producing headwaters to the Napo floodplain are the volcanically active Ecuadorian Andes, which discharge sediment at a cosmogenic nuclide-based denudation rate of 0.49 ± 0.12 mm/yr. This denudation rate was calculated from an average ¹⁰Be nuclide concentration of 2.2 ± 0.5 × 10⁴ at/g_(Qz) that was measured in bedload-derived quartz. Within the Napo lowlands, a significant drop in trunk stream ¹⁰Be nuclide concentrations relative to the Andean hinterland is recorded, with an average concentration of 1.2 ± 0.5 × 10⁴ at/g_(Qz). This nuclide concentration represents a mixture between the ¹⁰Be nuclide concentration of eroded floodplain deposits, and that of sediment eroded from the Andean hinterland that is now carried in the trunk stream. Evidence for addition of sediment from the floodplain to the trunk stream is provided by published decadal-scale sediment flux measurements from gauging stations operated in the Napo basin, from which an increase from 12 × 10⁶ t/yr at the outflow of the Andes to ～47 × 10⁶ t/yr at the confluence with the Solimões (upper Amazon River) is recorded. Therefore, approximately 35 × 10⁶ t of floodplain sediment are added annually to the active Napo trunk stream. Combined with our nuclide concentration measurements, we can estimate that the eroded floodplain deposits yield a nuclide concentration of ～0.9 × 10⁴ at/g_(Qz) only. Under steady state surface erosion conditions, this nuclide concentration would translate to a denudation rate of the floodplain of ～0.47 mm/yr. However, we have no geomorphologic explanation for this high denudation rate within the low relief floodplain and thus suggest that this low-nuclide concentrated sediment is Andean-derived and would have been deposited in the floodplain at a time when erosion rates of the Andes were elevated. Therefore, the recently eroded floodplain sediment provides an Andean “paleo denudation rate” of 1.2 mm/yr that was calculated for high Andean production rates. A likely period for elevated erosion rates is the LGM, where climate and vegetation cover of the Andes differed from that of the Holocene. A possible cause for the erosion of the floodplain is the tectonic uplift of the Eastern Andes, which progressively shifts the Napo River northwards. Hence, the river cuts into ancient lowland sediment, which is admixed to the Andean sediment carried in the main Napo River.  相似文献