Thornthwaite Method Research Articles

Climatic Parameters Use for Evaluating Water Budget and Drought Analysis in Erbil Sub-basin, Kurdistan Region, Northern-Iraq

Major theoretical and practical hydrological issues may be solved using methods to maintain water balance. Evaluating the climate characteristics and environmental circumstances to be employed in the methods of water managing approach used in the Erbil sub-basin, northern Iraq, is the primary goal of this study. The studied area is a part of the region influenced by the Mediterranean climatological system. The climatic parameters of the research region were evaluated using the climatic data collected in the Erbil meteorological station for the period 1980-2022. The research result shows that the mean annual rainfall is 411.26 mm/year and the average monthly relative humidity is 41.12 %, the mean temperature is 20.62 °C, mean sunshine duration 8.35 hr./day and annual pan evaporation is 1200.96 mm / year. Potential evapotranspiration considered by Thornthwaite method is 1588.94 mm. The water surplus and deficit are 216.14 mm and 1393.81 mm, respectively. The surface runoff calculating from soil conservation system (SCS) technique which is about 86 mm / year and groundwater recharge is about 130.14 mm / year. The groundwater Budgets is about 187661880 m3 / year. The climatic situation in the area is variety from winter its wet to the summer its dry climates. Also, it could be measured that the climate in the area is determined was (Humid to very humid). The draught index according to SPI analysis show that the drought was observed during Moderately drought in (1983, 1999, 2000, 2010, 2015, and 2021) to severely drought in (2022.

Developing mathematical models to calculate annual evapotranspiration rates in Iraq using climate data.

Abstract Evapotranspiration is considered the fuel that controls the water cycle in the natural world. It is necessary for the stability of ecosystems and is involved in many important aspects in calculating groundwater quantities, determining optimal locations for building dams and reservoirs and knowing the water needs of crops. The work is divided into two main parts. The first includes the use of The Penman-Monteith method, which is considered the most standard method in the world according to the Food and Agriculture Organization (FAO), for calculating the annual rate of evapotranspiration in Iraq for the past fifteen years (2008-2022). The second part is a modification of a simple method for calculating evapotranspiration, which is the Thornthwaite method, to give results close to the accuracy of the Penman-Monteith method, as the modification was made using different statistical methods. The study showed the possibility of using the modified Thornthwaite method as an alternative to the Penman-Monteith method to calculate evapotranspiration in all regions of Iraq.

Climate classification for Northeast Brazil using reanalysis data and the Absolute Aridity Index

The climate of the Northeast Region of Brazil (NEB) has been intensively studied and analyzed for climate classification. The aridity index of the United Nations Environment Programme (UNEP) (AIUNEP) has been used for this purpose, but without fully satisfactory results. The input variables needed for its calculation are precipitation and reference potential evapotranspiration (ET0). However, although rainfall stations recording routine measurements of precipitation are well distributed in the NEB, they do not provide the necessary variables for estimating ET0. Thus, interpolation is used to calculate ET0, but this can generate errors. Another objective climate classification approach is the Thornthwaite method, based on the determination of the moisture index (Im), whose calculation also requires weather station data. Thus, seeking to circumvent the problem of paucity of stations and improve the spatial distribution of information on meteorological variables in the NEB, the present work had as one of its objectives to validate reanalysis data from ERA5 of the European Center for Medium-range Weather Forecast (ECMWF) and the unified gauge-based analysis of global daily precipitation project of the Climate Prediction Center/National Oceanic and Atmospheric Administration (CPC/NOAA). After validation, climate classifications were developed for the NEB using the AIUNEP and Im. It was observed that the Thornthwaite climate classification overestimated the aridity in the NEB, while the IAUNEP tended to underestimate it. For this reason, a new climate classification index, called the absolute aridity index (Iab), was suggested, yielding satisfactory results.

Determining climate classifications and producing climate border maps with GIS of Muğla province on the southern Aegean Sea coast of Türkiye

Climate is defined by the average of meteorological events observed over an extended period in a region, expressing the weather conditions of that area. Numerous scientists have developed various climate classifications. The fundamental purpose of these classifications is to distinguish different types of climates and thereby reveal similarities between regions. Such classifications can be based on factors like temperature and precipitation patterns. Understanding climate characteristics enables us to determine the boundaries of different climate types. This, in turn, is crucial for ensuring the sustainable use of regional resources and shaping land use plans. This study evaluates the process of creating climate boundary maps for Muğla province. Various climate classification methods, including Thornthwaite, Trewartha, Erinç, De Martonne, Köppen─Geiger, and Köppen, are comprehensively examined and compared. Our findings indicate that each method offers different approaches to defining Muğla’s climate, each with its unique advantages and limitations. For instance, while the Thornthwaite method provides detailed data, the Köppen─Geiger method offers a more generalized approach. The results suggest that combining various climate classification methods helps in more accurately and comprehensively mapping the climate boundaries of Muğla province. This study underscores the importance of integrating these diverse methods to contribute to the determination of climate boundaries and regional planning processes.

Assessment of crop water requirement and irrigation scheduling of potato using weather models under sub temperate climatic condition of North-Western Himalaya

To optimize irrigation water and enhance yield, appropriate amount of irrigation water and its scheduling according to real time weather data can help in reducing crop water foot prints. The evapotranspiration (ET) based irrigation scheduling using present weather conditions reflecting changed climatic scenarios in the study regions in the past few decades has proved to be sagacious use of water. To study the ET based irrigation scheduling, field experiment conducted with the treatments comprising four ET based weather models irrigation scheduling methods viz. no irrigation or rainfed, Thornthwaite, Hargreaves method, Temperature and modified Penman Monteith under sowing windows of 20th December and 20th January were conducted at research farm, of Department of Agronomy, CSK HPKV, Palampur, Himachal Pradesh during Rabi season of 2015-16. The estimated crop evapo-transpiration (ETc) with different ET estimation methods under North Western Himalayas showed variation during crop season. The highest estimated ET was observed in December as compared to January sown potato crop with Hargreaves method (376.8 mm) followed by Temperature (354 mm), Thornthwaite (329.5 mm) and the lowest in modified Penman Monteith methods (241.9 mm). The estimated ETc from pan evaporation observed to be the highest to the tune of (382.3 mm) compared to other methods of ETc estimation. The crop coefficients modeled at different pheno-phases were used for estimating water requirement of potato crop. It was found that irrigation scheduling based on modified Penman Monteith of ET estimation saved one irrigation to the tune of 60 mm during crop period without affecting significantly growth, and tuber yield of the potato as compared to other methods, viz., However, the irrigation schedule based on Thornthwaite method has recorded highest total potato tuber yield (171.76 q ha-1) being at par with irrigation schedules worked out from other ET estimation methods. The total water footprints were the lowest in modified Penman Monteith to the tune of 300 liters per kg of potato yield compared to other methods.

Monthly potential evapotranspiration estimated using the Thornthwaite method with gridded climate datasets in Southeastern Brazil

Monthly potential evapotranspiration estimated using the Thornthwaite method with gridded climate datasets in Southeastern Brazil

Estimation of Natural Groundwater Recharge in Altun Kopri Basin NE Iraq

The main objectives of the current study are to classify and assess the climate, estimate the actual evapotranspiration and runoff, determine the soil water budget, and estimate groundwater recharge. The climate of the study area is classified as Humid to Moist and Moist to Subarid. Evapotranspiration was determined by using the Thornthwaite method, with its annual value equal to 1342.68 mm. The Runoff was estimated by using the simple and widely used method of Soil Conservation Service Curve Number, the total runoff was 127.6 mm, which represents 36.44% of total rainfall precipitation. The groundwater recharge was estimated according to the modified Thornthwaite-Mather soil water budget, which equals 58.6 mm and represents 16.74 % of the total annual precipitation. The quantity of renewal groundwater is about 47.88 MCM.

AGROCLIMATIC ZONING OF ARABICA COFFEE CROPS IN THE REGION OF LAVRAS, MINAS GERAIS, BRAZIL

Coffee growing is the most relevant agricultural activity in the state of Minas Gerais. Arabica coffee (Coffea arabica L.) is the most widely cultivated in the state and is more sensitive to the climate, requiring milder temperatures for commercial production. Water deficit and airtemperature are the main factors used in the agroclimatic zoning of coffee, requiring annual water deficits below 150 mm and an average annual air temperature between 19°C and 21°C for suitability for cultivation. The Lavras region has municipalities with contrasting areas planted with Arabica coffee, being located in a transition zone of the growing crop. Therefore, the objective was to use interpolated climatic surfaces of mean monthly temperature and monthly precipitation, with high spatial resolution (30 seconds) of the WorldClim2 project, in order to perform the agroclimatic zoning for Arabica coffee in 11 municipalities around Lavras, Minas Gerais, Brazil. The water balance was calculated by the Thornthwaite method and the contour of existing plantations was obtained from a survey conducted by EPAMIG for the year 2018. The annual water deficit varied from 19 mm to 47 mm and the temperature from 17.5°C to 20.5°C. According to the geospatial analysis and scientific geovisualization techniques, it was observed that most of the region is suitable for cultivation of Arabica coffee, but spatial variations in water deficit may interfere with productivity and economic viability of implementation in certain areas.

Predicting Potential Evapotranspiration for Kalaburagi District using a Seasonal Arima Model

Forecasting potential evapotranspiration (PET) is of great importance in effectively managing irrigation systems. This article centers around models designed to simulate future PET levels for the Kalaburagi district. The study calculates potential evapotranspiration using temperature data in degrees Celsius, employing the Thornthwaite method, and prediction is performed using the Seasonal Autoregressive Moving Average (SARIMA) method. These models are developed based on autocorrelation function (ACF) and partial autocorrelation function (PACF) analysis. Model selection is based on minimizing Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC) values. The chosen models for different stations in Kalaburagi, Chincholi, Sedam, Chittapur, Aland, Jewargi, and Afzalpur respectively are SARIMA (1,0,1)(2,1,0)12, SARIMA(1,0,1)(2,1,0)12, SARIMA(1,0,0)(2,1,0)12, SARIMA(1,0,1)(2,1,0)12, SARIMA (1,0,1) (2,1,0) 12, and SARIMA(1,0,1)(2,1,0)12. The results indicate that the models developed for Jewargi and Chincholi stations show particular promise compared to the other two stations, with all four models performing well. These models have the potential to significantly enhance decision-making in irrigation planning and command area management practices, contributing to improved water resource management.

Analysis of the water-climatic balances by the Thornthwaite method in Dukan district

Water balances in any area are one of the main factors affecting water revenue, the natural environment, and vegetation cover. Water balance refers to the contribution of rainfall, temperature, evaporation, and impact on surface and groundwater in each region. In this research, an analytical and descriptive method was used to analyse the climate data used at Dukan climate station to determine the total amount of water between (2000-2022), which reached (1714.6 mm) For nine (9) months of the year, we have a shortage of water; only three (3) months have surpluses of water, which reached 130.1 mm. To prove whether the evaporation taken from Dukan climate station is the true evaporation of the water balance in the study area, we used the Thornthwaite equation to find out the true water balance based on temperature and annual rainfall for the same period. The results showed that the area had a water shortage of (1287.3 mm) for six (6) months and a surplus of (390.5 mm) for six (6) months. At the same time, the total evaporation, or evapotranspiration, reached (1461.9 mm). Based on the water balance equation, using scientific resources, and showing the relationship between precipitation and evaporation, the research concluded that the water balance varies from year to year depending on the amount of rainfall in the study area, but in general there is a water shortage in the study area during the year, and the highest water shortage in the region is in the summer months.

Regional Drought Analysis with Standardized Precipitation Evapotranspiration Index (SPEI): Gediz Basin, Turkey

In this study, regional drought analysis was performed with the Standard Precipitation Evapotranspiration Index (SPEI) and L moments techniques by using the monthly average temperature and monthly total rainfall amounts collected from five sites in the Gediz basin in Turkey. Using the monthly average temperatures, the potential evapotranspiration (PET) amounts obtained by the Thornthwaite method and the monthly total rainfall amounts are divided into 5 different reference periods as 1, 3, 6, 9 and 12 months. Expressing the difference between rainfall and potential evapotranspiration amounts, the water balance (Di) series shows that almost all of the 9 and 12 months periods suffers from water deficiency and the 3 months period is water excessive. After determining the distributions that provide the best adaptation to the water balance series, according to the SPEI values obtained, near-normal conditions prevailed in all sites, while moderate and severe arid and humid conditions sometimes occur, while extremely humid and arid conditions are rarely seen. In the regional drought analysis using L moment techniques with the SPEI values obtained, a region of 5 sites was accepted and the irregularity and heterogeneity measures showed that the basin was acceptable homogeneous. SPEI values are generally the best fit generalized extreme values (GEV) for 1 and 3 months periods, generalized normal (GNO) for 6 months period, generalized logistics (GLO) for 9 months period, Pearson type 3 (PE3) distributions for 12 months period. According to the regional SPEI values for reference periods, it has been found near-normal in 1.11, 1.25 and 2 years, moderately humid in 1.04 years, very humid conditions for 1.01 and 1.02 years, moderately dry in 4 and 5 years, severe arid in 10 years, and extremely dry conditions in 20 and longer periods.

Response of net primary productivity of vegetation to drought: A case study of Qinba Mountainous area, China (2001–2018)

Drought can significantly affect the carbon cycle of ecosystems. The Qinba Mountains region has a high potential for developing carbon sink forestry due to its strong carbon fixation capacity. This study applied the Carnegie-Ames-Stanford approach (CASA) model calculate monthly net primary productivity (NPP) in the region from 2001 to 2018. The standardized precipitation evapotranspiration indices (SPEI1-12) at various time scales were also analyzed by the Thornthwaite method, along with the test of significance and sustainability (Sen-MK-Hurst) model, to examine the persistent characteristics of dry and wet changes in the Qinba Mountains. The results of the correlation analysis between NPP and SPEI at multiple time scales showed that regional vegetation NPP is significantly impacted by drought, with the most sensitive months being July and October. On average, there is a four-month cumulative effect of drought on NPP. About 45.49% and 19.99% of NPP in the Qinba Mountains region are extremely or heavily sensitive to drought, with grasses being the most sensitive, followed by cultivated plants, deciduous broadleaved forests, mixed forests, sparse forests, and shrublands. The study also found that 40.99% of the region is expected to become wetter and 14.9% is expected to become drier in the future. Understanding the response of NPP to drought in this region can help with the management of regional climate change for environmental regulation.

Wetland water balance assessment: a case study of the Sosa wetland, Maseru, Lesotho

Abstract The Sosa wetland is a sensitive wetland, situated at the headwaters of the Jordan catchment in Maseru. Due to unregulated land use activities in the past decades (2010–2020), the Sosa wetland nearly dried up. Therefore, this study performed a wetland water balance of the Sosa wetland in Lesotho for the period of 1975–2020 using GIS and remote sensing. Landsat imageries of 1975–2020 were used for land use and land cover while the Penman -Monteith and Thornthwaite methods were used to estimate evapotranspiration. Results show that water/marsh, cultivation, settlements and bare-land increased by 2.04, 4.1, 5.82 and 28.71%, respectively, from 1975 to 2020. Forest and shrubs as well as grasslands decreased by 38.83 and 1.76%, respectively, from 1975 to 2020. Evapotranspiration estimates for the period 1984–2020 were in the range of 900 −1,071 mm/year which is substantially greater than the annual mean rainfall of the catchment which ranges from 550 to 850 mm/year. The most sensitive wetlands are found in the middle reach of the catchment and at the headwaters occupying about 16.03% of the catchment, whereas moderately sensitive wetlands occupy 39.75%. The water balance closure as a ratio of rainfall received ranged from −3.13 to −3.5.

Forecasting Potential Evapotranspiration for Yadgir District Karnataka, India using Seasonal Arima Model

The prediction of potential evapotranspiration (PET) is quite important task for reliable management of irrigation systems. This article is generally based on the models which try to mimic the actual occurrence of the Potential evapotranspiration in the future days for Yadgir district. In this study the potential evapotranspiration was estimated with the help of max and min temperature (o C) data using a Thornthwaite method and the prediction was carried out using the seasonal Autoregressive moving average method (SARIMA). The models were developed based upon autocorrelation function (ACF) and partial autocorrelation function (PACF). Furthermore, the model with the least Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC) values were selected. The models selected for different stations were ARIMA(2,0,2) (2,1,0)12, ARIMA(2,0,2)(2,1,0)12, ARIMA (1,0,1)(2,1,0)12, and ARIMA(2,0,2)(2,1,0)12, for Yadgir, Gurmitkal, Shahapur and Shorapur respectively. Furthermore, the results showed that the models developed for Gurmitkaland Shahapur were found to be quite promising compared to the other two stations. All four models were found to be producing better results. The models provided significant potential in improving the decision making in irrigation planning and command area management practices for better management of water resources.

Water budget of a Ramsar site in Ecuador

Wetlands have been degrading and disappearing due to several anthropogenic impacts, such as pollution by discharge of domestic and industrial wastewater, agricultural runoff, land conversion, etc. The assessment and forecast of hydrological processes in wetlands, namely inflows and outflows, is essential for developing and implementing plans aimed at managing and protecting wetlands areas. We estimated the water budget of a Ramsar site, La Tembladera wetland, for a two-year period (2018-2019) by using the water balance method. The evapotranspiration was calculated using the Thornthwaite method and the runoff was estimated using the Curve Number method. The proposed water balance model showed that the major inflows to the wetland were the San Agustín and Bellavista canals, and Estero Pinto, about 92.9% (2018) and 90.5% (2019) of the total inflows. The runoff and wastewater flows represented the minor inflows. The runoff was 0.003% in 2018 and 0.004% in 2019, whereas the wastewater volume accounted for 0.05% of all inflows in both years. The actual evapotranspiration was the major outflow in both years, being 67.1% (2018) and 73.6% (2019) of the total outflows. On the other hand, the irrigation canal was the minor outflow, 32.9% in 2018 and 26.4% in 2019. Therefore, La Tembladera wetland hydrology is mostly linked to the canals system and climate conditions, precipitation and actual evapotranspiration. Our findings could be the basis for further research and developing plans in order to rationally manage and protect this wetland of international importance.

Modeling the Water Balance of Agricultural Land in the Determination of the Growing Season in Buru Regency

This study aims to determine the value of surplus and water deviation of agricultural land in Namlea District, Buru Regency. The study was conducted in Namlea Subdistrict, Buru Regency, Maluku Province. Materials used, questionnaires, climate data, air temperature, precipitation, humidity, solar rays 10-20 years. Tools used, computer equipment, writing stationery and location maps. To obtain the surplus value and water deficit of the land used data on the average amount of monthly precipitation and the average monthly temperature using the calculation of the Thornthwaite method. The calculation of the groundwater balance is carried out using a bookkeeping system. The data used are monthly potential evapotranspiration values, climate station data, monthly average rainfall, and rainfall at a 50 percent chance level. The observation parameters calculated in this study are rainfall, evapotranspiration, and determination of land water balance. The results of this study showed that the difference in rainfall and evapotranspiration in Namlea District was highest in June at 85.40 mm, and the lowest in October at -99.83 mm. This value indicates that the evapotranspiration value is greater than the average monthly rainfall value during the period 2010 – 2019. Namlea Subdistrict experienced potential water loss for evaporation (APWL) in May of 35.30 mm, in August to November of August of 65.26 mm, in September of 156.24 mm, in October of 256.07 mm and in November of 303.45 mm. The land water balance in Namlea Subdistrict, namely rainwater deviation, occurs in May, then August to November, while the water surplus occurs in December to July, and continues in June and July. Namlea district annual runoff is 854.01 mm. Regarding agricultural irrigation development policies, this study recommends that it is necessary to pay attention to weaknesses in each food crop sub-sector.

Groundwater budgeting of Nari and Gaj formations and groundwater mapping of Karachi, Pakistan

Groundwater depletion is an emerging problem worldwide due to changes in climate and an increase in urbanization. Two significant water-bearing formations, the Oligocene-aged Nari and the Miocene-aged Gaj, were utilized as a case study exposed near Karachi, Pakistan. Groundwater budgeting was performed through a classical equation. The inflow of groundwater in the formations was calculated by thermo-pluviometric data and water loss of Hub Dam. The potential of evapotranspiration (PET) was calculated by the Thornthwaite method. The groundwater inflow from Hub Dam was estimated by using 20 years of annual water loss data by removing PET. The total mean annual inflow of groundwater in the formations was 2414.12 US Gallons per Second (gps). The annual mean outflow was estimated by calculation of groundwater usage for industries and domestic purposes and the mean annual groundwater outflow was 5562.61 US gps and an annual deficit of groundwater was 3148.5 US gps. The research is composed of validating the groundwater budget. Direct Current Electrical Resistivity (DCER) and static water level data from existing industrial wells were used for groundwater maps. The DCER data indicates A-Type and K-Type sub-surface with high resistivity in the three-layer model. The average water table of residential areas in 2019 was 60 m and in industrial areas was 130 m. The oscillation of the groundwater table over the last 20 years and the deficit of the groundwater budget shows an alarming condition for the future. If the same scenario persists, then by 2025, the water table will decline up to 140 m.

MONTHLY STREAM FLOWS ESTIMATION IN THE KARASU RIVER OF EUPHRATES BASIN WITH ARTIFICIAL NEURAL NETWORKS APPROACH

This study aims to estimate streamflow values with artificial neural networks (ANN) using various meteorological parameters. In developing the ANN model, various combinations of precipitation, air temperatures, and potential evapotranspiration values were used as inputs, and streamflow values were obtained. Meteorological data is divided into 70% train, 15% test, and 15% validation. In the model's design, various training algorithms, network architecture, input combinations, and the number of iterations were tried, and the most suitable model was tested. Correlation coefficient (R), coefficient of determination (R2), absolute error (AE), and absolute relative error (ARE) coefficients were compared, and the most suitable model was selected. According to the analysis results, the optimal model was obtained using 2000 iterations, the architecture of the 4-4-1 model, and the Quasi-Newton algorithm. It was determined that the ANNs successfully modeled the rainfall-runoff relationship and produced reliable estimates. In addition, it was revealed that the inclusion of potential evapotranspiration values obtained by the Thornthwaite method into the model increases the model's success.

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Water consumption of agricultural plants can be considered one of the main elements of the assessment needed for irrigation. Covering water needs during the growing season is done by applying irrigation. Quantitative studies on evapotranspiration performed on maize and sunflower crops showed different values. The average water consumption calculated according to the Thornthwaite method recorded the highest values in June, July and August. For the maize crop, the highest water consumption was reached in July (1480 m3 / ha or 27.1% of the total consumption), during which time the pollination, the growth of the cobs and the formation of the grain take place. In sunflower cultivation, the highest consumption was recorded in July (1302 m3 / ha or 28.2% of total consumption) and correspond to the phases of growth of the flowering head (inflorescence) and seed formation. The purpose of this paper is to establish the need for hydro-amelioration arrangements through a correct irrigation regime during the growing season following the results obtained based on water consumption in the crops studied. The present paper presents the results of water consumption in maize and sunflower crops, calculated according to the Thornthwaite method, as well as the correction coefficients for potential evapotranspiration conditions on the upper Prut river basin.

Banana growing and its climate suitability in the municipality of Recife-Pe, Brazil

The banana tree is a plant characteristic of the tropical region, demanding in temperatures and rainfall with good regional distribution, due to its low cost and high nutritional value, it is an integral part of the diet of populations. The objective is to analyze the climatic oscillations, from the calculation of the water balance and its climatic classification, according to the methods of Thorn Thwaite and Köppen, for the city of Recife, verifying the occurrence of the aptitude of the banana cultivar. The average rainfall and temperature data were acquired from the National Institute of Meteorology, for the period between 1962 and 2016. Banana plantations are moderate because they have a water deficit of 287.4 mm. The evaporative power registered in the municipal area is high, but the demand for irrigation complements the scarcity of water to cultivate it. The local altitude is in the range of planting of the cultivar as well as the variability of the relative humidity of the air. Wind is one of the limiting factors for commercial exploitation of banana cultivation, if the cultivars are tall and planted in sandy soils.