scholarly journals Prediction of Potential and Actual Evapotranspiration Fluxes Using Six Meteorological Data-Based Approaches for a Range of Climate and Land Cover Types

2021 ◽  
Vol 10 (3) ◽  
pp. 192
Author(s):  
Mirka Mobilia ◽  
Antonia Longobardi
Keyword(s):  
Water Cycle ◽  
Meteorological Data ◽  
Calibration Procedure ◽  
Heat Fluxes ◽  
Empirical Formulas ◽  
Climate Type ◽  
Index Method ◽  
Antecedent Precipitation ◽  
Wide Range ◽  
Vegetation And Climate

Evapotranspiration is the major component of the water cycle, so a correct estimate of this variable is fundamental. The purpose of the present research is to assess the monthly scale accuracy of six meteorological data-based models in the prediction of evapotranspiration (ET) losses by comparing the modelled fluxes with the observed ones from eight sites equipped with eddy covariance stations which differ in terms of vegetation and climate type. Three potential ET methods (Penman-Monteith, Priestley-Taylor, and Blaney-Criddle models) and three actual ET models (the Advection-Aridity, the Granger and Gray, and the Antecedent Precipitation Index method) have been proposed. The findings show that the models performances differ from site to site and they depend on the vegetation and climate characteristics. Indeed, they show a wide range of error values ranging from 0.18 to 2.78. It has been not possible to identify a single model able to outperform the others in each biome, but in general, the Advection-Aridity approach seems to be the most accurate, especially when the model calibration in not carried out. It returns very low error values close to 0.38. When the calibration procedure is performed, the most accurate model is the Granger and Gray approach with minimum error of 0.13 but, at the same time, it is the most impacted by this process, and therefore, in a context of data scarcity, it results the less recommended for ET prediction. The performances of the investigated ET approaches have been furthermore tested in case of lack of measured data of soil heat fluxes and net radiation considering using empirical relationships based on meteorological data to derive these variables. Results show that, the use of empirical formulas to derive ET estimates increases the errors up to 200% with the consequent loss of model accuracy.

scholarly journals Soil moisture and evapotranspiration of wetlands vegetation habitats retrieved from satellite images

2010 ◽  
Vol 7 (4) ◽  
pp. 5929-5955 ◽  
Author(s):  
K. Dabrowska-Zielinska ◽  
M. Budzynska ◽  
W. Kowalik ◽  
K. Turlej
Keyword(s):  
Soil Moisture ◽  
Satellite Images ◽  
Water Cycle ◽  
Incidence Angle ◽  
Meteorological Data ◽  
Wave Length ◽  
Ground Truth ◽  
Test Site ◽  
Heat Fluxes ◽  
Ramsar Convention

Abstract. The research has been carried out in Biebrza Ramsar Convention test site situated in the N-E part of Poland. Data from optical and microwave satellite images have been analysed and compared to the detailed soil-vegetation ground truth measurements conducted during the satellite overpasses. Satellite data applied for the study include: ENVISAT.ASAR, ENVISAT.MERIS, ALOS.PALSAR, ALOS.AVNIR-2, ALOS.PRISM, TERRA.ASTER, and NOAA.AVHRR. Optical images have been used for classification of wetlands vegetation habitats and vegetation surface roughness expressed by LAI. Also, heat fluxes have been calculated using NOAA.AVHRR data and meteorological data. Microwave images have been used for the assessment of soil moisture. For each of the classified wetlands vegetation habitats the relationship between soil moisture and backscattering coefficient has been examined, and the best combination of microwave variables (wave length, incidence angle, polarization) has been used for mapping and monitoring of soil moisture. The results of this study give possibility to improve models of water cycle over wetlands ecosystems by adding information about soil moisture and surface heat fluxes derived from satellite images. Such information is very essential for better protection of the European sensitive wetland ecosystems. ENVISAT and ALOS images have been obtained from ESA for AO ID 122 and AOALO.3742 projects.

scholarly journals Modelling Actual Evapotranspiration Seasonal Variability by Meteorological Data-Based Models

Hydrology ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 50 ◽  
Author(s):  
Mirka Mobilia ◽  
Marius Schmidt ◽  
Antonia Longobardi
Keyword(s):  
Prediction Models ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Threshold Value ◽  
Heat Fluxes ◽  
Actual Evapotranspiration ◽  
Net Radiation ◽  
Antecedent Precipitation ◽  
Annual Dynamic ◽  
Eddy Covariance Measurements

This study aims at illustrating a methodology for predicting monthly scale actual evapotranspiration losses only based on meteorological data, which mimics the evapotranspiration intra-annual dynamic. For this purpose, micrometeorological data at the Rollesbroich and Bondone mountain sites, which are energy-limited systems, and the Sister site, a water-limited system, have been analyzed. Based on an observed intra-annual transition between dry and wet states governed by a threshold value of net radiation at each site, an approach that couples meteorological data-based potential evapotranspiration and actual evapotranspiration relationships has been proposed and validated against eddy covariance measurements, and further compared to two well-known actual evapotranspiration prediction models, namely the advection-aridity and the antecedent precipitation index models. The threshold approach improves the intra-annual actual evapotranspiration variability prediction, particularly during the wet state periods, and especially concerning the Sister site, where errors are almost four times smaller compared to the basic models. To further improve the prediction within the dry state periods, a calibration of the Priestley-Taylor advection coefficient was necessary. This led to an error reduction of about 80% in the case of the Sister site, of about 30% in the case of Rollesbroich, and close to 60% in the case of Bondone Mountain. For cases with a lack of measured data of net radiation and soil heat fluxes, which are essential for the implementation of the models, an application derived from empirical relationships is discussed. In addition, the study assessed whether this variation from meteorological data worsened the prediction performances of the models.

scholarly journals Using Satellite Data for CBRN (Chemical, Biological, Radiological, and Nuclear) Threat Detection, Monitoring, and Modelling

2021 ◽  
Author(s):  
Gary Sutlieff ◽  
Lucy Berthoud ◽  
Mark Stinchcombe
Keyword(s):  
Satellite Data ◽  
Meteorological Data ◽  
Atmospheric Composition ◽  
Chemical Detection ◽  
List Type ◽  
Data Types ◽  
Wide Range ◽  
Future Technologies ◽  
The Impact ◽  
Near Future

Abstract CBRN (Chemical, Biological, Radiological, and Nuclear) threats are becoming more prevalent, as more entities gain access to modern weapons and industrial technologies and chemicals. This has produced a need for improvements to modelling, detection, and monitoring of these events. While there are currently no dedicated satellites for CBRN purposes, there are a wide range of possibilities for satellite data to contribute to this field, from atmospheric composition and chemical detection to cloud cover, land mapping, and surface property measurements. This study looks at currently available satellite data, including meteorological data such as wind and cloud profiles, surface properties like temperature and humidity, chemical detection, and sounding. Results of this survey revealed several gaps in the available data, particularly concerning biological and radiological detection. The results also suggest that publicly available satellite data largely does not meet the requirements of spatial resolution, coverage, and latency that CBRN detection requires, outside of providing terrain use and building height data for constructing models. Lastly, the study evaluates upcoming instruments, platforms, and satellite technologies to gauge the impact these developments will have in the near future. Improvements in spatial and temporal resolution as well as latency are already becoming possible, and new instruments will fill in the gaps in detection by imaging a wider range of chemicals and other agents and by collecting new data types. This study shows that with developments coming within the next decade, satellites should begin to provide valuable augmentations to CBRN event detection and monitoring. Article Highlights There is a wide range of existing satellite data in fields that are of interest to CBRN detection and monitoring. The data is mostly of insufficient quality (resolution or latency) for the demanding requirements of CBRN modelling for incident control. Future technologies and platforms will improve resolution and latency, making satellite data more viable in the CBRN management field

scholarly journals A multi-site, year-round turbulence microstructure atlas for the deep perialpine Lake Garda

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sebastiano Piccolroaz ◽  
Bieito Fernández-Castro ◽  
Marco Toffolon ◽  
Henk A. Dijkstra
Keyword(s):  
Turbulent Mixing ◽  
Meteorological Data ◽  
Time Of Day ◽  
Monthly Basis ◽  
Lake Garda ◽  
Standardized Protocol ◽  
Wide Range ◽  
Buoyancy Driven Convection ◽  
Monitoring Activity ◽  
Additional Monitoring

AbstractA multi-site, year-round dataset comprising a total of 606 high-resolution turbulence microstructure profiles of shear and temperature gradient in the upper 100 m depth is made available for Lake Garda (Italy). Concurrent meteorological data were measured from the fieldwork boat at the location of the turbulence measurements. During the fieldwork campaign (March 2017-June 2018), four different sites were sampled on a monthly basis, following a standardized protocol in terms of time-of-day and locations of the measurements. Additional monitoring activity included a 24-h campaign and sampling at other sites. Turbulence quantities were estimated, quality-checked, and merged with water quality and meteorological data to produce a unique turbulence atlas for a lake. The dataset is open to a wide range of possible applications, including research on the variability of turbulent mixing across seasons and sites (demersal vs pelagic zones) and driven by different factors (lake-valley breezes vs buoyancy-driven convection), validation of hydrodynamic lake models, as well as technical studies on the use of shear and temperature microstructure sensors.

scholarly journals Transferability Intercomparison: An Opportunity for New Insight on the Global Water Cycle and Energy Budget

2007 ◽  
Vol 88 (3) ◽  
pp. 375-384 ◽  
Author(s):  
E. S. Takle ◽  
J. Roads ◽  
B. Rockel ◽  
W. J. Gutowski ◽  
R. W. Arritt ◽  
...  
Keyword(s):  
Energy Budget ◽  
Climate Models ◽  
Climate Model ◽  
Water Cycle ◽  
Regional Climate ◽  
Climate Conditions ◽  
Continental Scale ◽  
Global Water Cycle ◽  
Wide Range ◽  
Global Water

A new approach, called transferability intercomparisons, is described for advancing both understanding and modeling of the global water cycle and energy budget. Under this approach, individual regional climate models perform simulations with all modeling parameters and parameterizations held constant over a specific period on several prescribed domains representing different climatic regions. The transferability framework goes beyond previous regional climate model intercomparisons to provide a global method for testing and improving model parameterizations by constraining the simulations within analyzed boundaries for several domains. Transferability intercomparisons expose the limits of our current regional modeling capacity by examining model accuracy on a wide range of climate conditions and realizations. Intercomparison of these individual model experiments provides a means for evaluating strengths and weaknesses of models outside their “home domains” (domain of development and testing). Reference sites that are conducting coordinated measurements under the continental-scale experiments under the Global Energy and Water Cycle Experiment (GEWEX) Hydrometeorology Panel provide data for evaluation of model abilities to simulate specific features of the water and energy cycles. A systematic intercomparison across models and domains more clearly exposes collective biases in the modeling process. By isolating particular regions and processes, regional model transferability intercomparisons can more effectively explore the spatial and temporal heterogeneity of predictability. A general improvement of model ability to simulate diverse climates will provide more confidence that models used for future climate scenarios might be able to simulate conditions on a particular domain that are beyond the range of previously observed climates.

Direct Liquid Cooling of High Flux LED Systems: Hot Spot Abatement

2013 ◽  
Author(s):  
Enes Tamdogan ◽  
Mehmet Arik ◽  
M. Baris Dogruoz
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Light Extraction ◽  
Junction Temperature ◽  
System Level ◽  
Design Parameters ◽  
Liquid Cooling ◽  
Wide Range

With the recent advances in wide band gap device technology, solid-state lighting (SSL) has become favorable for many lighting applications due to energy savings, long life, green nature for environment, and exceptional color performance. Light emitting diodes (LED) as SSL devices have recently offered unique advantages for a wide range of commercial and residential applications. However, LED operation is strictly limited by temperature as its preferred chip junction temperature is below 100 °C. This is very similar to advanced electronics components with continuously increasing heat fluxes due to the expanding microprocessor power dissipation coupled with reduction in feature sizes. While in some of the applications standard cooling techniques cannot achieve an effective cooling performance due to physical limitations or poor heat transfer capabilities, development of novel cooling techniques is necessary. The emergence of LED hot spots has also turned attention to the cooling with dielectric liquids intimately in contact with the heat and photon dissipating surfaces, where elevated LED temperatures will adversely affect light extraction and reliability. In the interest of highly effective heat removal from LEDs with direct liquid cooling, the current paper starts with explaining the increasing thermal problems in electronics and also in lighting technologies followed by a brief overview of the state of the art for liquid cooling technologies. Then, attention will be turned into thermal consideration of approximately a 60W replacement LED light engine. A conjugate CFD model is deployed to determine local hot spots and to optimize the thermal resistance by varying multiple design parameters, boundary conditions, and the type of fluid. Detailed system level simulations also point out possible abatement techniques for local hot spots while keeping light extraction at maximum.

Purification of pulp mill condensates by an adsorptive process on activated carbon

Holzforschung ◽  
2019 ◽  
Vol 73 (6) ◽  
pp. 589-597 ◽  
Author(s):  
José A.F. Gamelas ◽  
Sofia M. Rebola ◽  
Margarita G. Evtyugina ◽  
Valdemar I. Esteves ◽  
Dmitry V. Evtuguin
Keyword(s):  
Activated Carbon ◽  
Volatile Compounds ◽  
Water Cycle ◽  
Black Liquor ◽  
Pulp Mill ◽  
Dimethyl Disulfide ◽  
Pulp Mills ◽  
Wide Range ◽  
New Process ◽  
Pseudo Second Order

Abstract In order to close the water cycle in pulp mills with condensates instead of fresh water, the malodorous/hazardous volatile compounds and colored substances have to be removed by appropriate efficient methods. In the present work, the condensate from the evaporation of black liquor (BL) from a kraft mill was purified by a batch adsorptive process by means of commercial activated carbon (AC). The effluent was found to contain a wide range of aromatic and organosulfur volatile compounds, including toluene, ethylguaicol, syringaldehyde, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), 2,3-dimethylthiophene, benzothiol and benzothiophene derivatives. Methanol was the major volatile organic component in the condensate (201 mg l−1), which was, however, poorly adsorbed on the AC surface. Aromatics and organosulfur contaminants were adsorbed almost completely in 2–5 min at 23°C under the optimized AC load (900 mg l−1). The treatment allowed the elimination of up to 99% of the obnoxious odor, color and turbidity of the condensate. The adsorption equilibrium followed the Langmuir model and the pseudo-second-order kinetics. The new process could be incorporated in the pulp mill with relatively low additional reagent costs.

scholarly journals A Mobile Sensing System for UrbanPM2.5Monitoring with Adaptive Resolution

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Hongjie Guo ◽  
Guojun Dai ◽  
Jin Fan ◽  
Yifan Wu ◽  
Fangyao Shen ◽  
...  
Keyword(s):  
Air Quality ◽  
Meteorological Data ◽  
Computational Cost ◽  
Estimation Method ◽  
Mobile Sensing ◽  
Prototype System ◽  
Adaptive Grids ◽  
Sensing System ◽  
Adaptive Resolution ◽  
Wide Range

This paper develops a mobile sensing system, the first system used in adaptive resolution urban air quality monitoring. In this system, we employ several taxis as sensor carries to collect originalPM2.5data and collect a variety of datasets, including meteorological data, traffic status data, and geographical data in the city. This paper also presents a novel method AG-PCEM (Adaptive Grid-Probabilistic Concentration Estimation Method) to infer thePM2.5concentration for undetected grids using dynamic adaptive grids. We gradually collect the measurements throughout a year using a prototype system in Xiasha District of Hangzhou City, China. Experimental data has verified that the proposed system can achieve good performance in terms of computational cost and accuracy. The computational cost of AG-PCEM is reduced by about 40.2% compared with a static grid method PCEM under the condition of reaching the close accuracy, and the accuracy of AG-PCEM is far superior as widely used artificial neural network (ANN) and Gaussian process (GP), enhanced by 38.8% and 14.6%, respectively. The system can be expanded to wide-range air quality monitor by adjusting the initial grid resolution, and our findings can tell citizens actual air quality and help official management find pollution sources.

scholarly journals Turbulent fluxes above the snow surface

1998 ◽  
Vol 26 ◽  
pp. 179-183 ◽  
Author(s):  
Eric Martin ◽  
Yves Lejeune
Keyword(s):  
Surface Energy Balance ◽  
Meteorological Data ◽  
Energy Balance Equation ◽  
Turbulent Fluxes ◽  
Heat Fluxes ◽  
Indirect Measurements ◽  
Radiative Fluxes ◽  
Stable Conditions ◽  
Sonic Anemometers ◽  
Snow Model

Measurements of sensible- and latent-heat fluxes under stable conditions are rare. In order to obtain indirect measurements of turbulent fluxes, meteorological data measured at the Col de Porte laboratory (1320 m a.s.l, France) under very stable conditions (cold, clear night with low wind) are used. The radiative fluxes are measured, the conduction within the snowpack is calculated using the snow model Crocus and the turbulent fluxes are determined as a residual term of the surface-energy balance equation. These data were used to fit a new parameterization of the turbulent fluxes for the snow model. The turbulent fluxes are increased as compared to the theory. Crocus was also applied to the data from the LEADEX92 experiment and the turbulent fluxes calculated by the model were compared to the fluxes measured using sonic anemometers/thermometers on the site.

scholarly journals A countrywide analysis of 27 solar power plants installed at different climates

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Talat Ozden
Keyword(s):  
Power Plant ◽  
Alternative Energy ◽  
Power Plants ◽  
Solar Power ◽  
Meteorological Data ◽  
Energy Sources ◽  
Climate Classification ◽  
Climate Type ◽  
Monthly Average ◽  
The World

AbstractThe world is still heavily using nonconventional energy sources, which are worryingly based on carbon. The step is now alternative energy sources hoping that they will be more environmentally friendly. One of the important energy conversion forms by using these sources is photovoltaic solar systems. These type of power plants is on the increase in everyday on the world. Before investment a solar power plant in a specified region, a techno-economic analyse is performed for that power plant by using several meteorological data like solar irradiance and ambient temperature. However, this analyses generally lacks evaluation on effects of climatic and geographical conditions. In this work, 5 years of data of 27 grid-connected photovoltaic power plants are investigated, which are installed on seven different climate types in Turkey. Firstly, the power plants are categorized considering the tilt angles and Köppen–Gieger climate classification. The performance evaluations of the plants are mainly conducted using monthly average efficiencies and specific yields. The monthly average efficiencies, which were classified using the tilts and climate types were from 12 to 17%, from 12 to 16% and from 13 to 15% for tilts 30°/10°, 25° and 20°, respectively. The variation in the specific yields decrease with elevation as y(x) =  − 0.068x + 1707.29 (kWh/kWp). As the performances of photovoltaic systems for some locations within the Csb climatic regions may relatively lower than some other regions with same climate type. Thus, techno-economic performance for PVPP located in this climate classification should be carefully treated.

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