scholarly journals Comparative Study of Evapotranspiration Variation and its Relationship with other Climatic Parameters in Asaba and Uyo

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Okwunna M Umego ◽  
Temitayo A Ewemoje ◽  
Oluwaseun A Ilesanmi
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Small Variation ◽  
Climatic Variables ◽  
Maximum Temperature ◽  
Climatic Parameters ◽  
Sunshine Hours

This study was carried out to assess the variations of Reference Evapotranspiration (ETO also denoted with RET) calculated using FAO-56 Penman Monteith model of two locations Asaba and Uyo and evaluate its relationships with the variations of other climatic parameters. Meteorological data of forty one years (1975-2015) and thirty five years (1981-2015) period for Asaba and Uyo, respectively gotten from Nigeria Meteorological Agency, Abuja were used. It was observed that the variations of Evapotranspiration (ET) in both locations were in line with two seasons (rainy and dry) normally experienced in Nigeria having its highest value in March (4.8 mm/day) for Asaba and for Uyo in February (4.5 mm/day); and its lowest value in August (3.1 mm/day) for Asaba and in July (2.9 mm/day) for Uyo. ET variation when compared with other climatic variables in both locations was observed to have the same trend with maximum temperature, solar radiation and sunshine hours. It also has the same variation with minimum temperature though with slight deviation. It was observed that ET variation is inversely proportional to the variation relative humidity. Wind speed displayed relatively small variation in its trend over the study period and is not in line with the variations of ET.Keywords— Evapotranspiration, Climatic Variables, FAO Penman-Monteith Model, Variations

Clustering analysis of regional reference evapotranspiration and its components based on climatic variables across northeast China, 1961–2010

2015 ◽  
Vol 7 (1) ◽  
pp. 128-141 ◽  
Author(s):  
Yuan Liu ◽  
Buchun Liu ◽  
Xiaojuan Yang ◽  
Wei Bai
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Northeast China ◽  
Reference Evapotranspiration ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Regional Distribution ◽  
Climatic Variables ◽  
Maximum Temperature ◽  
Sunshine Hours

Evapotranspiration integrates atmospheric demand and surface conditions. The Penman-Monteith equation was used to calculate annual and seasonal reference evapotranspiration (ET0) and thermodynamic and aerodynamic components (ETrad and ETaero) at 77 stations across northeast China, 1961–2010. The results were: (1) annual ETrad and ETaero had different regional distribution, annual ETrad values decreased from south to north, whereas the highest ETaero values were recorded in the eastern and western regions, the lowest in the central region; (2) seasonal ETaero distributions were similar to seasonal ET0, with a south–north longitudinal pattern, while seasonal ETrad distributions had a latitudinal east-west pattern; and (3) in the group for ET0 containing 69 sampling stations, effects of climatic variables on ET0 followed sunshine hours > relative humidity > maximum temperature > wind speed. Changes in sunshine hours had the greatest effect on ETrad, but wind speed and relative humidity were the most important variables to ETaero. The decline in sunshine duration, wind speed, or both over the study period appeared to be the major cause of reduced potential evapotranspiration in most of NEC. Wind speed had opposite effects on ETrad and ETaero, and therefore the effect of wind speed on ET0 was not significant.

Weather Forecasting in Coastal Districts of Odisha and Andhra Pradesh by Using Time Series Analysis

2018 ◽  
Vol 6 (8) ◽  
pp. 85
Author(s):  
Naresh Patnaik ◽  
F Baliarsingh
Keyword(s):  
Time Series ◽  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Time Series Analysis ◽  
Andhra Pradesh ◽  
Maximum Temperature ◽  
Climatic Parameters ◽  
Series Analysis ◽  
Annual Maximum Temperature

Climate change in world is always one of the most important topics in Water Resources. Now the issue is so predominant that it is gradually restricting out social life, peace and harmony. Climate change is a change in the statistical distribution of weather pattern of an area, when such changes occur for a long period of time. Weather is the state of atmosphere at a particular place and time. Climate is the long term statistical expression of short term weather. This study presents a comprehensive assessment of the future climate pattern/weather prediction by taking different climatic parameters such as temperature, precipitation, solar radiation, wind speed and relative humidity by using time series analysis. The study area of research work covers the coastal districts of Odisha and some parts of Andhra Pradesh. The climatic parameters are collected over last 20 years (1993-2013) from the selected 10 stations and the prediction is made using Time Series Analysis (ARIMA Model). The annual maximum temperature, solar radiation of all districts indicates a statistically significant increase in trend, whereas in the case of wind speed and relative humidity indicates significant deceasing trend. The annual rain fall shows an increasing trend of 2.69 mm/year in all station except Srikakulam, Khordha, Jagatsinghpur and Balasore which shows a decreasing trend of 1.94, 1.29, 0.56 and 1.18 mm/year respectively. As a whole the annual maximum temperature and solar radiation shows an increase trend of 0.16 ⁰C and 0.073 MJ/m² per year respectively. Further the wind speed and relative humidity of all stations indicates a decreasing trend of 0.056 m/s and 0.003(Units in fraction) per year respectively.

scholarly journals Trend and Sensitivity Analysis of Reference Evapotranspiration in the Senegal River Basin Using NASA Meteorological Data

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1957
Author(s):  
Papa Malick Ndiaye ◽  
Ansoumana Bodian ◽  
Lamine Diop ◽  
Abdoulaye Deme ◽  
Alain Dezetter ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
River Basin ◽  
Reference Evapotranspiration ◽  
Climatic Variables ◽  
Maximum Temperature ◽  
Senegal River ◽  
Senegal River Basin ◽  
Basin Area

Understanding evapotranspiration and its long-term trends is essential for water cycle studies, modeling and for water uses. Spatial and temporal analysis of evapotranspiration is therefore important for the management of water resources, particularly in the context of climate change. The objective of this study is to analyze the trend of reference evapotranspiration (ET0) as well as its sensitivity to climatic variables in the Senegal River basin. Mann-Kendall’s test and Sen’s slope were used to detect trends and amplitude changes in ET0 and climatic variables that most influence ET0. Results show a significant increase in annual ET0 for 32% of the watershed area over the 1984–2017 period. A significant decrease in annual ET0 is observed for less than 1% of the basin area, mainly in the Sahelian zone. On a seasonal scale, ET0 increases significantly for 32% of the basin area during the dry season and decreases significantly for 4% of the basin during the rainy season. Annual maximum, minimum temperatures and relative humidity increase significantly for 68%, 81% and 37% of the basin, respectively. However, a significant decrease in wind speed is noted in the Sahelian part of the basin. The wind speed decrease and relative humidity increase lead to the decrease in ET0 and highlight a “paradox of evaporation” in the Sahelian part of the Senegal River basin. Sensitivity analysis reveals that, in the Senegal River basin, ET0 is more sensitive to relative humidity, maximum temperature and solar radiation.

scholarly journals Evaluation of FAO-56 Procedures for Estimating Reference Evapotranspiration Using Missing Climatic Data for a Brazilian Tropical Savanna

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1763
Author(s):  
Luiz Claudio Galvão do Valle Júnior ◽  
George L. Vourlitis ◽  
Leone Francisco Amorim Curado ◽  
Rafael da Silva Palácios ◽  
José de S. Nogueira ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Water Resource Management ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Climatic Conditions ◽  
Climatic Variables ◽  
Climatic Data ◽  
Wet Season ◽  
Radiation Data

The Brazilian savanna (Cerrado) has been heavily impacted by agricultural activities over the last four to five decades, and reliable estimates of reference evapotranspiration (ETo) are needed for water resource management and irrigation agriculture. The Penman–Monteith (PM) is one of the most accepted models for ETo estimation, but it requires many inputs that are not commonly available. Therefore, assessing the FAO guidelines to compute ETo when meteorological data are missing could lead to a better understanding of which variables are critically important for reliable estimates of ETo and how climatic variables are related to water requirements and atmospheric demands. In this study, ETo was computed for a grass-dominated part of the Cerrado from April 2010 to August 2019. We tested 12 different scenarios considering radiation, relative humidity, and/or wind speed as missing climatic data using guidelines given by the FAO. Our results presented that wind speed and actual vapor pressure do not affect ETo estimates as much as the other climatic variables; therefore, in the Cerrado’s conditions, wind speed and relative humidity measurements are less required than temperature and radiation data. When radiation data were missing, the computed ETo was overestimated compared to the benchmark. FAO procedures to estimate the net radiation presented good results during the wet season; however, during the dry season, their results were overestimated because the method could not estimate negative Rn. Our results indicate that radiation data have the highest impact on ETo for our study area and presumably for regions with similar climatic conditions. In addition, those FAO procedures for estimating radiation are not suitable when radiation data are missing.

scholarly journals Analysis of the NASA-POWER system for estimating reference evapotranspiration in the Comarca Lagunera, Mexico

2021 ◽  
Vol 13 (2) ◽  
pp. 201-226
Author(s):  
Sergio Iván Jiménez-Jiménez ◽  
◽  
Waldo Ojeda-Bustamante ◽  
Marco Antonio Inzunza-Ibarra ◽  
Mariana de Jesús Marcial-Pablo ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Reanalysis Data ◽  
Measured Data ◽  
System Data ◽  
Data Source

Introduction: The FAO-56 Penman-Monteith (PM) is one of the most solid and commonly used methods for estimating reference evapotranspiration (ETo); however, it requires meteorological data that are not always available, so an alternative is the use of reanalysis data. Objective: To estimate the error that the NASA-POWER (NP) system data can generate in the ETo of the Comarca Lagunera, Mexico. Methodology: Daily and decadal average ETo were estimated in five different ways. In each case, a different method was used to estimate ETo (FAO-56 PM or Hargreaves and Samani [HS]) and a different meteorological data source (measured, NP data or combination of both). Results: NP data can be used to provide temperature, solar radiation and relative humidity variables, but not wind speed. The NP data overestimate the measured ETo, an RMSE of 1.15 and 0.89 mm∙d-1 was found for daily and decadal periods, respectively. Limitations of the study: A grid error analysis could not be carried out because the number of stations is limited. Originality: The use of reanalysis data to estimate ETo has not been analyzed locally. Conclusion: When measured data are not available, NP data and the HS equation can be used. When using the FAO-56 PM method and NP data, the in situ wind speed must be available.

Trends in major climatic parameters and sensitivity of evapotranspiration to climatic parameters in the eastern Himalayan region of Sikkim, India

2019 ◽  
Vol 11 (2) ◽  
pp. 491-502
Author(s):  
G. T. Patle ◽  
D. Sengdo ◽  
M. Tapak
Keyword(s):  
Sensitivity Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Minimum Temperature ◽  
Reference Evapotranspiration ◽  
Himalayan Region ◽  
Series Data ◽  
Maximum Temperature ◽  
Climatic Parameters ◽  
Eastern Himalayan Region

Abstract In this study, temporal trends in daily time series data of key climatic parameters were analyzed using Mann–Kendall and Sen's slope estimator. Sensitivity analysis of each climatic parameter on reference evapotranspiration (ETo) was performed to estimate the sensitivity coefficients and to evaluate the impact of global warming on ETo in the eastern Himalayan region of Sikkim, India. Results of trend analysis showed a significant increasing trend for minimum temperature and mean temperature. Mean relative humidity and sunshine duration showed decreasing trends. Reference evapotranspiration also showed a significant decreasing trend by 0.008 mm year–1 in Sikkim state of India. Sensitivity analysis revealed that the seasonal and annual ETo were most sensitive to maximum temperature followed by sunshine hours whereas wind speed, minimum temperature and relative humidity had a fluctuating effect on mean ETo. The sensitivity coefficient indicated that ETo changes positively with maximum and minimum temperature, sunshine hour, and wind speed, while it changes negatively with relative humidity. Analysis indicated that increase in relative humidity would decrease the ETo in the study area. The findings of this study would be useful for sustainable water resources planning and management of agriculture in hilly regions of the state and for development of adaptation strategies in adverse climatic conditions.

scholarly journals Performance of different methods for reference evapotranspiration estimation in Jaíba, Brazil

2018 ◽  
Vol 22 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Gustavo H. da Silva ◽  
Santos H. B. Dias ◽  
Lucas B. Ferreira ◽  
Jannaylton É. O. Santos ◽  
Fernando F. da Cunha
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Standard Method ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Air Humidity ◽  
Method Performance ◽  
Relative Air Humidity ◽  
Evapotranspiration Estimation ◽  
Missing Variables

ABSTRACT FAO Penman-Monteith (FO-PM) is considered the standard method for the estimation of reference evapotranspiration (ET0) but requires various meteorological data, which are often not available. The objective of this work was to evaluate the performance of the FAO-PM method with limited meteorological data and other methods as alternatives to estimate ET0 in Jaíba-MG. The study used daily meteorological data from 2007 to 2016 of the National Institute of Meteorology’s station. Daily ET0 values were randomized, and 70% of these were used to determine the calibration parameters of the ET0 for the equations of each method under study. The remaining data were used to test the calibration against the standard method. Performance evaluation was based on Willmott’s index of agreement, confidence coefficient and root-mean-square error. When one meteorological variable was missing, either solar radiation, relative air humidity or wind speed, or in the simultaneous absence of wind speed and relative air humidity, the FAO-PM method showed the best performances and, therefore, was recommended for Jaíba. The FAO-PM method with two missing variables, one of them being solar radiation, showed intermediate performance. Methods that used only air temperature data are not recommended for the region.

scholarly journals SEASONAL AND INTERANNUAL PATTERN OF METEOROLOGICAL VARIABLES IN CUIABÁ, MATO GROSSO STATE, BRAZIL

2015 ◽  
Vol 33 (3) ◽  
pp. 477 ◽  
Author(s):  
Nadja Gomes Machado ◽  
Marcelo Sacardi Biudes ◽  
Carlos Alexandre Santos Querino ◽  
Victor Hugo De Morais Danelichen ◽  
Maísa Caldas Souza Velasque
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Meteorological Data ◽  
Seasonal Pattern ◽  
Global Radiation ◽  
Meteorological Variables ◽  
Maximum Temperature ◽  
Wet Season ◽  
Agricultural Producers ◽  
Mato Grosso

ABSTRACT. Cuiab´a is located on the border of the Pantanal and Cerrado, in Mato Grosso State, which is recognized as one of the biggest agricultural producers of Brazil. The use of natural resources in a sustainable manner requires knowledge of the regional meteorological variables. Thus, the objective of this study was to characterize the seasonal and interannual pattern of meteorological variables in Cuiab´a. The meteorological data from 1961 to 2011 were provided by the Instituto Nacional de Meteorologia (INMET – National Institute of Meteorology). The results have shown interannual and seasonal variations of precipitation, solar radiation, air temperature and relative humidity, and wind speed and direction, establishing two main distinct seasons (rainy and dry). On average, 89% of the rainfall occurred in the wet season. The annual average values of daily global radiation, mean, minimum and maximum temperature and relative humidity were 15.6 MJ m–2 y–1, 27.9◦C, 23.0◦C, 30.0◦C and 71.6%, respectively. Themaximum temperature and the wind speed had no seasonal pattern. The wind speed average decreased in the NWdirectionand increased in the S direction.Keywords: meteorological variables, climatology, ENSO. RESUMO. Cuiabá está localizado na fronteira do Pantanal com o Cerrado, no Mato Grosso, que é reconhecido como um dos maiores produtores agrícolas do Brasil. A utilização dos recursos naturais de forma sustentável requer o conhecimento das variáveis meteorológicas em escala regional. Assim, o objetivo deste estudo foi caracterizar o padrão sazonal e interanual das variáveis meteorológicas em Cuiabá. Os dados meteorológicos de 1961 a 2011 foram fornecidos pelo Instituto Nacional de Meteorologia (INMET). Os resultados mostraram variações interanuais e sazonais de precipitação, radiação solar, temperatura e umidade relativa do ar e velocidade e direção do vento, estabelecendo duas principais estações distintas (chuvosa e seca). Em média, 89% da precipitação ocorreu na estação chuvosa. Os valores médios anuais de radiação diária global, temperatura do ar média, mínima e máxima e umidade relativa do ar foram 15,6 MJ m–2 y–1, 27,9◦C, 23,0◦C, 30,0◦C e 71,6%, respectivamente. A temperatura máxima e a velocidade do vento não tiveram padrão sazonal. A velocidade média do vento diminuiu na direção NW e aumentou na direção S.Palavras-chave: variáveis meteorológicas, climatologia, ENOS.

scholarly journals Future climate uncertainty and spatial variability over Tamilnadu State, India

2015 ◽  
Vol 17 (1) ◽  
pp. 175-185
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Minimum Temperature ◽  
Climate Models ◽  
Regional Climate ◽  
Future Climate ◽  
Maximum Temperature ◽  
Projection Data ◽  
Climate Uncertainty

<div> <p>The present study analyses future climate uncertainty for the 21st century over Tamilnadu state for six weather parameters: solar radiation, maximum temperature, minimum temperature, relative humidity, wind speed and rainfall. The climate projection data was dynamically downscaled using high resolution regional climate models, PRECIS and RegCM4 at 0.22&deg;x0.22&deg; resolution. PRECIS RCM was driven by HadCM3Q ensembles (HQ0, HQ1, HQ3, HQ16) lateral boundary conditions (LBCs) and RegCM4 driven by ECHAM5 LBCs for 130 years (1971-2100). The deviations in weather variables between 2091-2100 decade and the base years (1971-2000) were calculated for all grids of Tamilnadu for ascertaining the uncertainty. These deviations indicated that all model members projected no appreciable difference in relative humidity, wind speed and solar radiation. The temperature (maximum and minimum) however showed a definite increasing trend with 1.8 to 4.0&deg;C and 2.0 to 4.8&deg;C, respectively. The model members for rainfall exhibited a high uncertainty as they projected high negative and positive deviations (-379 to 854 mm). The spatial representation of maximum and minimum temperature indicated a definite rhythm of increment from coastal area to inland. However, variability in projected rainfall was noticed.</p> </div> <p>&nbsp;</p>

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