scholarly journals Effect of de-trending climatic parameters on temporal changes of reference evapotranspiration in the eastern Himalayan region of Sikkim, India

2021 ◽  
Author(s):  
Vanita Pandey ◽  
Indira Taloh ◽  
P. K. Pandey
Keyword(s):  
Relative Humidity ◽  
Reference Evapotranspiration ◽  
Irrigation Scheduling ◽  
Maximum Temperature ◽  
Linear Regression Method ◽  
Climatic Parameters ◽  
Study Region ◽  
Dry Spell ◽  
Nonlinear Trends ◽  
Linear And Nonlinear

Abstract Reference Evapotranspiration (ET0) is an essential factor in irrigation scheduling, climate change studies, and drought assessment. The study's main objective was to identify the influences of detrending input climatic parameters (CPs) on ET0 using linear and nonlinear approaches throughout 1980–2015 in Gangtok, East Sikkim, India. The benchmark values of ET0 were calculated using the global standard FAO56 Penman–Montieth equation. The ET0-related CPs included for the analysis are maximum temperature (Tmax), minimum temperature (Tmin), maximum relative humidity (RHmax), minimum relative humidity (RHmin), and sunshine duration (SSH). The linear and nonlinear trends in various CPs affect ET0 change. Linearly detrended series was obtained by linear regression method whereas, nonlinearly detrended series was obtained using Complete Ensemble Empirical Mode Decomposition with Adaptive Noise method. Twenty-three scenarios, including the original scenario, 11 scenarios in Group1 (CPs de-trended linearly), and 11 scenarios in Group2 (CPs de-trended nonlinearly) were generated. Influences of Tmax and SSH were more substantial than the influences of other CPs for both Group1 and Group2. This results in the SSH masked the weak influences of other CPs. The effects of the trends in CPs, especially of SSH and Tmax, were clearly shown. The ET0 values decreased significantly during 1980–2015; however, no significant decreasing trend was observed in the case of SSH, during the same period. The nonlinear detrending gave closer results to the benchmark values as compared to linear detrending because of non-monotone variations of the ET0 and CPs. Therefore, the results from nonlinear detrending were more plausible as compared to linear detrending. The diminishing trend of ET0 prompted an overall alleviation in dry spell, hence there would be a somewhat lower risk of water use in the study region.

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

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 Long term monthly and inter-seasonal weather variability analysis for the lower Shivalik foothills of Punjab

MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 173-180
Author(s):  
NAVNEET KAUR ◽  
M.J. SINGH ◽  
SUKHJEET KAUR
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Linear Regression Method ◽  
Post Monsoon ◽  
Sunshine Hours ◽  
Annual Minimum Temperature ◽  
Weather Parameters

This paper aims to study the long-term trends in different weather parameters, i.e., temperature, rainfall, rainy days, sunshine hours, evaporation, relative humidity and temperature over Lower Shivalik foothills of Punjab. The daily weather data of about 35 years from agrometeorological observatory of Regional Research Station Ballowal Saunkhri representing Lower Shivalik foothills had been used for trend analysis for kharif (May - October), rabi (November - April), winter (January - February), pre-monsoon (March - May), monsoon (June - September) and post monsoon (October - December) season. The linear regression method has been used to estimate the magnitude of change per year and its coefficient of determination, whose statistical significance was checked by the F test. The annual maximum temperature, morning and evening relative humidity has increased whereas rainfall, evaporation sunshine hours and wind speed has decreased significantly at this region. No significant change in annual minimum temperature and diurnal range has been observed. Monthly maximum temperature revealed significant increase except January, June and December, whereas, monthly minimum temperature increased significantly for February, March and October and decreased for June. Among different seasons, maximum temperature increased significantly for all seasons except winter season, whereas, minimum temperature increased significantly for kharif and post monsoon season only. The evaporation, sunshine hours and wind speed have also decreased and relative humidity decreased significantly at this region. Significant reduction in kharif, monsoon and post monsoon rainfall has been observed at Lower Shivalik foothills. As the region lacks assured irrigation facilities so decreasing rainfall and change in the other weather parameters will have profound effects on the agriculture in this region so there is need to develop climate resilient agricultural technologies.

scholarly journals Investigation of the Annual Variability of the Aleppo Pine Tree-Rings Width: the Relationships with the Climatic Conditions in the Attica Basin

2013 ◽  
Vol 11 (4) ◽  
pp. 583-592 ◽  
Keyword(s):  
Tree Rings ◽  
Climatic Conditions ◽  
Aleppo Pine ◽  
Total Variance ◽  
Maximum Temperature ◽  
Monthly Precipitation ◽  
Climatic Parameters ◽  
Study Region ◽  
Annual Variability ◽  
Pine Tree

The relationships between the annual variability of the Aleppo pine tree-ring widths and the variability of the main climatic parameters in the Attica basin are analysed in the present study for a 45-year period (1959-2003). The Principal Components Analysis was applied to the times-series of the tree-rings indices (12 populations) as well as to the residual timeseries of the monthly precipitation, maximum and minimum temperatures derived from 5 meteorological stations located in the study region. The results showed that the 64% of the total variance of the tree-rings of the Aleppo pine could be attributed to the common variability of the climatic parameters: for precipitation with 82.6%, for minimum temperature with 88.2% and for maximum temperature with 88.5% of the total variance of each parameter. Characteristic narrow and wide tree-rings were observed during the hydrological years with extreme rainfall or temperature conditions. Finally the study of the climate – growth links, on a local basis, showed that the growth of the Aleppo pine is related positively (positive correlations) with the winter and spring precipitations. On the other hand negative correlations were found with the temperatures of the spring months.

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 A smartphone APP for weather-based irrigation scheduling using artificial neural networks

2020 ◽  
Vol 55 ◽  
Author(s):  
Lucas Borges Ferreira ◽  
Fernando França da Cunha ◽  
Rubens Alves de Oliveira ◽  
Thiago Ferreira Rodrigues
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Relative Humidity ◽  
Reference Evapotranspiration ◽  
Smartphone Application ◽  
Irrigation Scheduling ◽  
Rainfall Data ◽  
Artificial Neural ◽  
Monteith Equation ◽  
Irrigation Requirements

Abstract: The objective of this work was to develop a smartphone application (APP) for a weather-based irrigation scheduling using artificial neural networks (ANNs), as well as to validate it in a green corn (Zea mays) crop. An APP (IrriMobile) that uses ANNs based on temperature and relative humidity, or on temperature only, was developed to estimate the reference evapotranspiration (ETo). The APP and Bernardo’s methodology for irrigation scheduling, with the ETo estimated by the FAO-56 Penman-Monteith equation, were used to schedule the irrigation for a green corn crop. The performance of empirical equations to estimate ETo was also assessed. Several corn morphological and agronomic characteristics were evaluated. The APP was used in the experiment with temperature, relative humidity, and rainfall data. Its use was also simulated with temperature and rainfall data only. There was no difference for any of the green corn characteristics evaluated. ETo estimation through the APP showed a higher performance than that by the evaluated equations. The APP overestimates the irrigation requirements by 8 and 19% when using temperature and relative humidity, and temperature only, respectively.

scholarly journals Design and analysis of statistical probability distribution and non-parametric trend analysis for reference evapotranspiration

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11597
Author(s):  
Sajid Gul ◽  
Jingli Ren ◽  
Neal Xiong ◽  
Muhammad Asif Khan
Keyword(s):  
Resource Management ◽  
Probability Distribution ◽  
Water Resource ◽  
Water Resource Management ◽  
Reference Evapotranspiration ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Statistical Probability ◽  
Study Region ◽  
Entire Study

Accurate estimates of reference evapotranspiration are critical for water-resource management strategies such as irrigation scheduling and operation. Therefore, knowledge of events such as spatial and temporal reference evapotranspiration (ETo) and their related principle of statistical probability theory plays a vital role in amplifying sustainable irrigation planning. Spatiotemporal statistical probability distribution and its associated trends have not yet has explored in Pakistan. In this study, we have two objectives: (1) to determine the most appropriate statistical probability distribution that better describes ETo on mean monthly and seasons wise estimates for the design of irrigation system in Khyber Pakhtunkhwa, and (2) to check the trends in ETo on a monthly, seasonal, and annual basis. To check the ETo trends, we used the modified version of the Mann-Kendall and Sen Slope. We used Bayesian Kriging for spatial interpolation and propose a practical approach to the design and study of statistical probability distributions for the irrigation system and water supplies management. Also, the scheme preeminent explains ETo, on a monthly and seasonal basis. The statistical distribution that showed the best fit ETo result occupying 58.33% and 25% performance for the design of irrigation scheme in the entire study region on the monthly level was Johnson SB and Generalized Pareto, respectively. However, according to the Anderson-Darling (AD) and Kolmogorov–Smirnov (KS) goodness of fit measure, seasonal ETo estimates were preferably suited to the Burr, Johnson SB & Generalized Extreme Value. More research work must be conduct to assess the significance of this study to other fields. In conclusion, these findings might be helpful for water resource management and policymaker in future operations.

scholarly journals Forecasting Reference Evapotranspiration Using Retrospective Forecast Analogs in the Southeastern United States

2012 ◽  
Vol 13 (6) ◽  
pp. 1874-1892 ◽  
Author(s):  
Di Tian ◽  
Christopher J. Martinez
Keyword(s):  
United States ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Southeastern United States ◽  
Department Of Energy ◽  
Maximum Temperature ◽  
Accurate Estimation ◽  
Hydrologic Simulation ◽  
Mean Values

Abstract Accurate estimation of reference evapotranspiration (ET0) is needed for determining agricultural water demand and reservoir losses and driving hydrologic simulation models. This study was conducted to explore the application of the National Centers for Environmental Prediction’s (NCEP’s) Global Forecast System (GFS) retrospective forecast (reforecast) dataset combined with the NCEP–U.S. Department of Energy (DOE) Reanalysis 2 dataset (R2) to forecast ET0 in the southeastern United States using a forecast analog approach. Seven approaches of estimating ET0 using the Penman–Monteith (PM) and Thornthwaite equations were evaluated by substitution of climatological mean values of variables or by bias correcting variables including solar radiation, maximum temperature, and minimum temperature using the R2 dataset. The skill of both terciles and extremes (10th and 90th percentiles) were evaluated. Overall, for the ET0 forecast approaches that combined R2 solar radiation with temperature, relative humidity, and wind speed from GFS, the reforecasts produced higher skill than methods that estimated parameters using GFS the reforecasts data only. The primary increase in skill was due to the use of relative humidity from the GFS reforecasts and long-term climatological mean values of solar radiation from the R2 dataset, indicating its importance in forecasting ET0 in the region. While the five categorical forecasts were skillful, the skill of upper and lower tercile forecasts was greater than that of lower and upper extreme forecasts and middle tercile forecasts. Most of the forecasts were skillful in the first 5 lead days.

scholarly journals Study of the Dependence of Effective Reproduction Number of COVID-19 on the Temperature and Humidity: A Case Study with the Indian States

2020 ◽  
Author(s):  
Manoj Mandal ◽  
Subhradeep Patra ◽  
Sabyasachi Pal ◽  
Suman Acharya ◽  
Mangal Hazra
Keyword(s):  
Relative Humidity ◽  
Reproduction Number ◽  
World Health ◽  
Mitigation Measures ◽  
Negative Slope ◽  
Maximum Temperature ◽  
Linear Regression Method ◽  
Indian States ◽  
Temperature And Humidity ◽  
The Impact

Corona Virus Disease 2019 (COVID-19) started in Wuhan province of China in November 2019 and within a short time, it was declared as a worldwide pandemic by World Health Organisation due to very fast worldwide spread of the virus. In the absence of any vaccine, various mitigation measures were used. In the past, the effect of temperature and humidity on the spread of the virus was studied for a very early phase of the data with mixed results. We are studying the impact of COVID-19 on the maximum temperature and relative humidity of a place using Indian states as test cases for SIR, SIRD, and SEIR models. We used a linear regression method to look for any dependency between effective reproduction number with maximum temperature and relative humidity. Most of the states show a correlation with the negative slope between the effective reproduction number with the maximum temperature and the relative humidity. It indicates that the effective reproduction number goes down as maximum temperature or relative humidity rise. But, the regression coefficient R2 is low for these correlations which means that the correlation is not strong.

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