scholarly journals Numerical Analysis of Sensitivity of Structure of the Stratification in Lake Biwa, Japan by Changing Meteorological Elements

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1492
Author(s):  
Jinichi Koue ◽  
Hikari Shimadera ◽  
Tomohito Matsuo ◽  
Akira Kondo

Climatic factors such as air temperature and wind speed can affect the structure of stratification in Lake Biwa. In general, the rise in air temperature and the decrease in wind speed weaken the vertical mixing and strengthen the structure of the stratification, which interrupts the transport of the substances. However, how much the change of each climate element can influence the structure of the stratification is not clarified. Therefore, it is important to evaluate the effects of each element on the stratification quantitatively. In the present study, we investigated the effect of the change in air temperature and wind speed on the seasonal change of stratification in Lake Biwa by using a three-dimensional hydrodynamic model. Numerical simulations were carried out for a baseline case using realistic meteorological data from 2007 to 2012 and hypothetical cases using meteorological data with modified air temperature or wind speed for sensitivity analysis. The analysis showed that the increase and decrease in air temperature changed the vertical water temperature uniformly in almost all layers. Thus, the strength of the stratification is hardly changed. The increase and decrease in wind speed, however, altered the water temperature near the surface of the lake, so that it significantly influenced the stratification. The increase in wind speed made the water parcels of the surface layer well mixed, and the decrease in wind speed made the mixed layer thinner.

Irriga ◽  
2017 ◽  
Vol 22 (2) ◽  
pp. 220-235
Author(s):  
Aureliano De Albuquerque Ribeiro ◽  
Aderson Soares De Andrade Júnior ◽  
Everaldo Moreira Da Silva ◽  
Marcelo Simeão ◽  
Edson Alves Bastos

COMPARAÇÃO ENTRE DADOS METEOROLÓGICOS OBTIDOS POR ESTAÇÕES CONVENCIONAIS E AUTOMÁTICAS NO ESTADO DO PIAUÍ, BRASIL*  AURELIANO DE ALBUQUERQUE RIBEIRO1; ADERSON SOARES DE ANDRADE JÚNIOR2; EVERALDO MOREIRA DA SILVA3; MARCELO SIMEÃO4 E EDSON ALVES BASTOS2 1Doutorando em Engenharia Agrícola, Universidade Federal do Ceará, Av. Mister Hull, s/n - Pici, bloco 804, 60455-760, Fortaleza - CE, [email protected] Embrapa Meio-Norte, Teresina, PI, [email protected], [email protected] Professor Adjunto II da Universidade Federal do Piauí, Campus Professora Cinobelina Elvas, Bom Jesus, PI, [email protected] Mestre em Agronomia: Solos e Nutrição de Plantas, Universidade Federal do Piauí, Campus Professora Cinobelina Elvas, Bom Jesus, PI, [email protected]*Extraído da dissertação de mestrado do primeiro autor  1 RESUMOO registro de elementos climáticos é efetuado por estações meteorológicas convencionais e automáticas. Porém, por questões operacionais e de custo, as estações automáticas estão substituindo as convencionais. Contudo, para que as séries de dados dessas estações sejam únicas, há a necessidade de estudos comparativos entre as duas estações. O estudo teve como objetivo comparar dados meteorológicos obtidos por estações convencionais (EMC) e automáticas (EMA) em municípios do Estado do Piauí (Paulistana, Picos, São João do Piauí, Floriano, Parnaíba e Piripiri). Os elementos meteorológicos avaliados foram: temperaturas do ar máxima (°C) mínima (ºC) e média (ºC), umidade relativa média do ar (%), velocidade do vento a 10 m (m s-1), precipitação pluviométrica (mm) e pressão atmosférica média (hPa). As comparações dos dados foram feitas por meio dos seguintes indicadores estatísticos: precisão (R2), erro absoluto médio (EAM), coeficiente de correlação (r), índice de concordância de Willmott (d) e índice de confiança (c). Os melhores ajustes dos dados foram constatados para a precipitação e pressão atmosférica; intermediários, para a temperatura do ar, umidade relativa do ar média e os piores, para a velocidade do vento. A umidade relativa média do ar foi o elemento analisado que mostrou as maiores diferenças entre a EMC e a EMA. Palavras-chave: Agrometeorologia, elementos climáticos, sensores. RIBEIRO, A. A.; ANDRADE JÚNIOR, A. S.; SILVA, E.M.; SIMEÃO, M.; BASTOS, E.A.COMPARISON OF METEOROLOGICAL DATA RECORDED BY CONVENTIONAL AND AUTOMATIC STATIONS IN PIAUÍ STATE, BRAZIL   2 ABSTRACTClimatic elements are recorded by both conventional and automatic weather stations. However, due to cost and operational issues, automatic stations are replacing the conventional. So that  data sets from these stations are unique, there is a need for comparative studies between the two types of stations. The aim of this study was to compare meteorological data obtained by conventional and automatic stations in towns of the State of Piauí, Brazil (Paulistana, Picos, São João do Piauí, Floriano and Piripiri).The meteorological elements evaluated were: maximum (°C) minimum (°C) and average (°C) air temperature, average relative humidity (%), wind speed at 10 m (m s-1), rainfall (mm) and average atmospheric pressure (hPa). Data comparison was by the following statistical indicators: precision (R2), mean absolute error (EAM), Pearson correlation coefficient (r), Willmott’s index of agreement (d) and confidence index (c).  The best data adjustments were observed for rainfall and atmospheric pressure; intermediates for the air temperature, average relative humidity and worst for the wind speed.  The air average relative humidity was the analyzed element that showed the greatest differences between EMC and EMA. Keywords: Agrometeorology, meteorological elements, sensors 


2016 ◽  
Vol 20 (5) ◽  
pp. 1681-1702 ◽  
Author(s):  
Madeline R. Magee ◽  
Chin H. Wu ◽  
Dale M. Robertson ◽  
Richard C. Lathrop ◽  
David P. Hamilton

Abstract. The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911–2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s−1 before 1994 to 3.74 m s−1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (−1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911–1980, 1981–1993, and 1994–2014) delineated by abrupt changes in air temperature and wind speed. Average summer hypolimnetic temperature and fall turnover date exhibit significant differences between the third period and the first two periods. Changes in ice cover (ice-on and ice-off dates, ice cover duration, and maximum ice thickness) exhibit an abrupt change after 1994, which was related in part to the warm El Niño winter of 1997–1998. Under-ice water temperature, freeze-over water temperature, hypolimnetic temperature, fall turnover date, and stratification duration demonstrate a significant difference in the third period (1994–2014), when air temperature was warmest and wind speeds decreased rather abruptly. The trends in ice cover and water temperature demonstrate responses to both long-term and abrupt changes in meteorological conditions that can be complemented with numerical modeling to better understand how these variables will respond in a future climate.


2016 ◽  
Vol 20 (7) ◽  
pp. 2573-2587 ◽  
Author(s):  
Zhongwei Huang ◽  
Hanbo Yang ◽  
Dawen Yang

Abstract. With global climate changes intensifying, the hydrological response to climate changes has attracted more attention. It is beneficial not only for hydrology and ecology but also for water resource planning and management to understand the impact of climate change on runoff. In addition, there are large spatial variations in climate type and geographic characteristics across China. To gain a better understanding of the spatial variation of the response of runoff to changes in climatic factors and to detect the dominant climatic factors driving changes in annual runoff, we chose the climate elasticity method proposed by Yang and Yang (2011). It is shown that, in most catchments of China, increasing air temperature and relative humidity have negative impacts on runoff, while declining net radiation and wind speed have positive impacts on runoff, which slow the overall decline in runoff. The dominant climatic factors driving annual runoff are precipitation in most parts of China, net radiation mainly in some catchments of southern China, air temperature and wind speed mainly in some catchments in northern China.


2020 ◽  
Author(s):  
Hemant Kulkarni ◽  
Harshwardhan Vinod Khandait ◽  
Uday Wasudeorao Narlawar ◽  
Pragati G Rathod ◽  
Manju Mamtani

Whether weather plays a part in the transmissibility of the novel COronaVIrus Disease-19 (COVID-19) is still not established. We tested the hypothesis that meteorological factors (air temperature, relative humidity, air pressure, wind speed and rainfall) are independently associated with transmissibility of COVID-19 quantified using the basic reproduction rate (R0). We used publicly available datasets on daily COVID-19 case counts (total n = 108,308), three-hourly meteorological data and community mobility data over a three-month period. Estimated R0 varied between 1.15-1.28. Mean daily air temperature (inversely) and wind speed (positively) were significantly associated with time dependent R0, but the contribution of countrywide lockdown to variability in R0 was over three times stronger as compared to that of temperature and wind speed combined. Thus, abating temperatures and easing lockdown may concur with increased transmissibility of COVID-19.


Author(s):  
Iug Lopes ◽  
Marcos V. da Silva ◽  
Juliana M. M. de Melo ◽  
Abelardo A. de A. Montenegro ◽  
Héliton Pandorfi

ABSTRACT Spatial variability analysis of meteorological elements and precise identification of possible causes of thermal stress in poultry housing help producers in the decision making process. The objective of this study was to evaluate the internal environment of poultry houses in the downtime (sanitary void) and in the production phase, to characterize spatial thermal variability and to identify critical control points. The study was carried out in the Alluvial Valley of the Mimoso River, municipality of Pesqueira, PE, Brazil. The data of air temperature, wind speed and illuminance were recorded in November (spring season), at 155 points within each poultry facility (10 x 90 m), spaced in a 3.0 x 2.5 m grid and subjected to descriptive statistical analysis and geostatistics. There was a strong spatial dependence for the variables air temperature, wind speed and illuminance. The ranges obtained for the air temperature in the facilities were from 48.22 to 114.52 m, while for the wind speed and illuminance were less than 10 m, thus revealing the need for greater homogeneity of the studied variables and meeting of the thermal requirement of the poultry.


2018 ◽  
Vol 64 (243) ◽  
pp. 89-99 ◽  
Author(s):  
JIZU CHEN ◽  
XIANG QIN ◽  
SHICHANG KANG ◽  
WENTAO DU ◽  
WEIJUN SUN ◽  
...  

ABSTRACTWe analyzed a 2-year time series of meteorological data (January 2011–December 2012) from three automatic weather stations on Laohugou glacier No. 12, western Qilian Mountains, China. Air temperature, humidity and incoming radiation were significantly correlated between the three sites, while wind speed and direction were not. In this work, we focus on the effects of clouds on other meteorological parameters and on glacier melt. On an average, ~18% of top-of-atmosphere shortwave radiation was attenuated by the clear-sky atmosphere, and clouds attenuated a further 12%. Most of the time the monthly average increases in net longwave radiation caused by clouds were larger than decreases in net shortwave radiation but there was a tendency to lose energy during the daytime when melting was most intense. Air temperature and wind speed related to turbulent heat flux were found to suppress glacier melt during cloudy periods, while increased water vapor pressure during cloudy days could enhance glacier melt by reducing energy loss by latent heat. From these results, we have increased the physical understanding of the significance of cloud effects on continental glaciers.


2013 ◽  
Vol 718-720 ◽  
pp. 1547-1553 ◽  
Author(s):  
Neng Sheng Bao ◽  
Shi Liang Fei ◽  
Xue Jia Huang ◽  
Tie Quan Liu ◽  
Jin Huang

The design of domestic drying oven lacked theoretical basis and methods, especially a tool supporting experiments and verifying the results of theoretical research. This paper developed a platform, which can be used to automatically detect multi-point air temperature and wind speed from drying oven nozzle of printing and coating machines. The hardware design of platform achieves a four-axis positioning function by adopt a three-dimensional Cartesian coordinate robot and an additional servo motor. The LabVIEW-based software design of platform achieves many functions, including multi-axis positioning control, data acquisition and processing, data interface and operation interface. This platform contributes to research work for drying oven.


2018 ◽  
Vol 40 ◽  
pp. 20
Author(s):  
Mauren Lucila Marques de Morais Micalichen ◽  
Nelson Luís da Costa Dias

The use of alternative sources of meteorological data has become increasingly common, making it possible to evaluate areas with no long or continuous series of meteorological data. In this context, the main objective of this study is to evaluate the performance of data series from the National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP/NCAR) for the state of Minas Gerais and verify the possible use of them in the absence of data observations of air temperature and wind speed. The analyzes were performed by comparing observation data from 17 meteorological stations and reanalysis data of the CFSR and CFSV2 models. From the results of the statistical analysis, it is observed that the air temperature reanalysis data presented a good performance in the region of study. However, wind speed data show a weak correlation. These results show that the air temperature data from these reanalyses have the potential to be used as an alternative source of data. Further studies are suggested regarding the use of wind speed data from these reanalyses.


2021 ◽  
Vol 261 ◽  
pp. 04010
Author(s):  
Chang Liu ◽  
Shiyan Wang ◽  
Liang Wang ◽  
Xiaobo Liu ◽  
Huaidong Zhou ◽  
...  

Thermal stratification which is common in water bodies is subject to such factors as the water depth of the water body (a lake or reservoir, for instance), the fluidity of the water and the local meteorological conditions. The stable thermal stratification in reservoirs will lead to changes in the physical and chemical properties of the water as well as distribution of aquatic creatures, hence leaving an impact on the water quality. The Daheiting Reservoir was taken as the research object in this study. Based on the continuous monitored water temperature data in the reservoir, the tempo-spatial change features of the water temperature structure in the reservoir were analyzed, and the driving factors of thermal stratification in the reservoir was studied. The research found that air temperature, wind speed, and hydrodynamic factors are the driving factors for the thermal stratification and corresponding water temperature change patterns in Daheiting Reservoir. Among these factors, air temperature is the fundamental precondition, the wind speed is the auxiliary precondition, and the hydrodynamic factors are the disturbance factors for thermal stratification in the Reservoir. All these factors act together to cause the thermal stratification pattern and evolution features in Daheiting Reservoir.


2018 ◽  
Vol 69 (8) ◽  
pp. 2005-2011
Author(s):  
Marin Rusanescu ◽  
Carmen Otilia Rusanescu ◽  
Gigel Paraschiv

In this paper we analyze the correlation between meteorological parameters (wind speed and direction, relative humidity, air temperature) and atmospheric pollutants in Bucharest during the cold period 26.02.2018-02.03.2018, which was based on the monitoring of the concentrations of nitrogen oxides, NO2, O3 and SO2 sulfur dioxide within 24 h and the occurrence of exceedances above the prescribed limit. It was found based on the results obtained that the wind direction influences not only the concentrations of pollutants but also the correlation between the pollutants. Traffic pollutants were at the highest concentration when the wind speed was low. We have found that the highest average concentration for NO2, NOx, NO, O3 occurred at 90% indicative humidity for vertical mixing of strong pollutants. Sulfur dioxide did not record exceeding over the limit standard in the analyzed period.


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