Thornthwaite Method Research Articles

Comparisons of sequential water balances between 1920-2018 in the municipality of Serra Talhada and São Bento do Una – Pe, Brazil

A sequential water balance was performed using the Thorn Thwaite and Mather method in order to verify the contribution of water storage and damming in the municipality of São Bento do Una in relation to the water crisis. The monthly average climatological precipitation data were grouped into 95 years, characterizing a period of climatological normal, where the software was used in electronic spreadsheets to extract the values ​​of the monthly, annual averages of precipitation for the period from 1920 to 2018. Were estimated by the multiple regression line methods applied to the T-estima software, taking into account the geographic coordinates. Climatic impacts have caused changes in the region's water balance in the last decade. Environmental degradation, the local effect of human action, has by itself accelerated the process of modifying the regional climate, thus directly affecting the conditions of the rainfall regime and the availability of water in the soil. It is extremely necessary to use rainwater harvesting and other storage sources for human, animal and plant survival, thus contributing to the agricultural and poultry sector in the region. Climatic impacts may cause changes in the region's water balance, as heavy and short-lived rains are expected, leading to a drop in poultry and agricultural production.

Forecasting potential evapotranspiration for Raichur district 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 a Raichur district. In this study the potential evapotranspiration was estimated with the help of max and min temperature (°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)(1,1,2)12, ARIMA(1,0,1)(2,1,0)12, ARIMA(1,0,1)(1,1,2)12 and ARIMA(1,0,1) (2,1,0)12 for Riachur, Manvi, Sindhanuru and Lingasuguru respectively. Furthermore, the results showed that the models developed for Manvi and Sindhanuru were found to be quite promising compared to the other two stations. All four models were found to be producing better results up to a lead time forecast of one month. The models provided significant potential in improving the decision making in irrigation planning and command area management practices for better management of water resources.

Coffee pest severity by agrometeorological models in subtropical climate.

This study aimed to estimate the number of generations and cycle duration of the southern red mite, coffee berry borer, and coffee leaf miner using the thermal index to assist in controlling these main coffee pests in the state of Paraná, Brazil. The data of maximum and minimum air temperature (°C) and precipitation (mm) of all municipalities in the state from 1984 to 2018 were collected from the National Aeronautics and Space Administration/Prediction of Worldwide Energy Resources (NASA/POWER). The reference evapotranspiration was estimated using the (Camargo Campinas IAC Boletim 116:9, 1971) method and the water balance was calculated using the method of ( Thornthwaite C, Mather J (1955) The water balance publications in climatology, 8 (1). DIT, Laboratory of climatology, Centerton, NJ, USA). The basal temperature of each pest minus the average temperature of the years was used to calculate the degrees-day, the duration of the pest cycle, and the number of generations per year. The influence of altitude on the development of coffee pests was measured using the Pearson correlation. The thermal index is able to estimate the damage caused by coffee pests in the state of Pará, Brazil. Coffee pests show greater severity in the north of Paraná, in the regions with the highest temperatures. It is the same region that concentrates most of the coffee production of the state. The results of the life cycle and number of generations were interpolated for the entire state using the kriging method. Coffee pests showed the highest severity in the north region of the state of Paraná, more specifically in the Northwest, North Central, and West Central mesoregions. These regions have concentrated most of the state's coffee production. Mesoregions with the highest coffee production in the state showed higher susceptibility to coffee pests. Altitude showed a high correlation (r > 0.6) with the cycle variability and number of generations of coffee pests. The average cycles of the coffee berry borer, coffee leaf miner, and southern red mite are 24.13 (± 8.34), 45.64 (± 18.61), and 21.51 (± 3.51) days, respectively. The average annual generation was 16.67 (± 4.77), 9.02 (± 2.75), and 17.32 (± 2.63) generations, for the coffee berry borer, the coffee red mite, and the southern red mite, respectively.

English

A study was carried out to assess the DRAINMOD model in predicting the role of Controlled Drainage strategies and Drain Spacing scenarios in the paddy field. The DRAINMOD model was simulated for the current (2018), Near Future 2021 to 2060 and Far Future 2061 to 2099 in the Kunshan region, China. Potential Evapotranspiration was estimated by the Thornthwaite method. The model performed good agreement in predicting paddy’s water balance for the period of 2017-18. Also, Projections of the future climate in the Kunshan region, showed that there will be a decrease in the annual precipitation during rice-growing seasons for both Near Future (2021-2060) and Far Future (2061-2099). The DRAINMOD model was utilized to evaluate the impact of such a future decrease in precipitation on ground Water Tables Depth. Compared to the rice-growing season of 2018, DRAINMOD simulations showed that future Water Table Depths will drop by 38% to 40% for both the Near Future and Far Future under the Representative Concentration Pathway (RCP) 4.5 and RCP 8.5. Such future remarkable drop in Water Table Depths may affect rice yield in the study region. The future water balance in the study area was re-simulated after replacing conventional drainage with Controlled Drainage and an increase in the drain spacing. Simulations revealed that practicing Controlled Drainage and an increase in drain spacing mitigated the future drop in Water Table Depths, thus ensuring better soil moisture conditions for rice. Therefore, Controlled Drainage approaches have the potential to cope with the adverse impacts of climate changes in the paddy fields.

Climate change and its effect on the soil water balance of Lages, Santa Catarina

Undertaken activities in agricultural, industrial and urban productions emit gases that increase the greenhouse effect and change both air temperature and precipitation. These changes damage the environment and agricultural production alike, as well as life on Earth. In light of this, the present study has as its objective to understand the climate regime in Lages/SC, a municipality located in southern Brazil, and analyze the effects of climate change on air temperature, precipitation, consecutive dry days and the soil water balance. To that end, historical series corresponding from 1948 to 2020 were used for maximum, average and minimum air temperatures, while the series from 1961 to 2020 were used for precipitation. In order to have the water balance calculated, precipitation and air temperature were considered as input data for the method of Thornthwaite and Mather (1955). As for potential evapotranspiration, soil water storage and available water capacity, they were calculated considering a Humic Dystrudept, classified according to the Soil Taxonomy. Temporal analyses regarding air temperature, precipitation, evapotranspiration, consecutive dry days, intense rains and water balance were conducted by using the Mann-Kendall trend test (0.05). A positive and increasing trend was observed for maximum, average and minimum air temperatures, as well as for the precipitation over the years. Although rainfall volume has increased over time, periods with fifteen consecutive dry days have been increasingly frequent. Despite the changes in temperature, precipitation and rainfall distribution, there were no changes observed in evapotranspiration, occurrence of intense rains or in the soil water balance.Keywords: Humic Dystrudept, air temperature, precipitation, evapotranspiration, water storage, greenhouse effect, Cambisols. Mudanças climáticas e seu efeito no balanço hídrico do solo de Lages, Santa Catarina.As atividades desenvolvidas nas produções agrícolas, industriais e urbanas emitem gases que aumentam o efeito estufa e alteram tanto a temperatura do ar quanto a precipitação. Essas mudanças prejudicam o meio ambiente e a produção agrícola, bem como a vida na Terra. Diante disso, o presente estudo tem como objetivo compreender o regime climático em Lages/SC, município localizado no sul do Brasil, e analisar os efeitos das mudanças climáticas na temperatura do ar, precipitação, dias secos consecutivos e balanço hídrico do solo. Para tanto, foram utilizadas séries históricas correspondentes de 1948 a 2020 para temperaturas máximas, médias e mínimas do ar, enquanto as séries de 1961 a 2020 foram utilizadas para precipitação. Para o cálculo do balanço hídrico, a precipitação e a temperatura do ar foram consideradas como dados de entrada para o método de Thornthwaite e Mather (1955). Quanto à evapotranspiração potencial, armazenamento de água no solo e capacidade hídrica disponível, foram calculados considerando um Distrudado Húmico, classificado de acordo com a Taxonomia do Solo. As análises temporais referentes à temperatura do ar, precipitação, evapotranspiração, dias secos consecutivos, chuvas intensas e balanço hídrico foram realizadas por meio do teste de tendência de Mann-Kendall (0,05). Foi observada uma tendência positiva e crescente para as temperaturas máximas, médias e mínimas do ar, bem como para a precipitação ao longo dos anos. Embora o volume de chuvas tenha aumentado ao longo do tempo, períodos com quinze dias secos consecutivos têm sido cada vez mais frequentes. Apesar das mudanças na temperatura, precipitação e distribuição das chuvas, não foram observadas alterações na evapotranspiração, ocorrência de chuvas intensas ou no balanço hídrico do solo.Palavras-chave: Disstrução Húmica, temperatura do ar, precipitação, evapotranspiração, armazenamento de água, efeito estufa, Cambissolos.

Comparative evaluation of precipitation-temperature based drought indices (DIs): A case study of Moroccan Lower Sebou basin

Due to the lack of studies on drought in the Lower Sebou basin (LSB), the complexity of drought event and the difference in climate conditions. The identification of the most appropriate drought indices (DIs) to assess drought conditions has become a priority. Therefore, assessing the performance of different drought indices was considered in order to identify the universal drought indices that are well adapted to the LSB. Based on data availability, five DIs were used: Standardized Precipitation Index (SPI), Standardized Precipitation and Evapotranspiration Index (SPEI), Reconnaissance Drought Index (RDI), self-calibrated Palmer Drought Severity Index (sc-PDSI) and Streamflow Drought Index (SDI). The DIs were calculated on an annual scale using monthly time series of precipitation, temperature and river flow from 1984-2016. Thornthwaite's method was used to calculate potential evapotranspiration (PET). Pearson's correlation (r) were analyzed. Furthermore, five decision criteria namely robustness, traceability, transparency, sophistication and scalability were used to evaluate the performance of these indices. The results proved the fact that SPI is suitable to detect the drought duration and intensity compared to other indices with high correlation coefficients especially in sub humid regions, knowing that it tends to give more results that are humid in stations with semi-arid climates. SPI, SPEI and RDI follow the same trend during the period studied. However, sc-PDSI appears to be the most sensitive to temperature and precipitation by overestimating the drought conditions. Eventually, the results of the performance evaluation criteria revealed that SPEI classified first (total score = 137) among other meteorological drought indices, followed by SPI, RDI and sc-PDSI.

Comparison of Meteorological Drought using SPI and SPEI

Drought assessment is crucial for effective water resources management in a river basin. Drought frequency has increased worldwide in recent years due to global warming. In this paper, an attempt is made to assess the meteorological drought in the Punpun river basin, India using two globally accepted drought indices namely, Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). The SPI and SPEI at 1-, 3-, 6-, 9-, and 12-month timescale were obtained to analyze the temporal variability of different drought levels. Correlation analysis of available observed data and gridded data has been carried out and the correlation coefficient was found to be 0.956. Hence gridded rainfall data from the year 1991 to 2020 is used for further analysis. Potential evapotranspiration (PET) used in the calculation of SPEI was computed by the Thornthwaite method. Water deficit was observed throughout as there is a decrease in rainfall and an increase in PET during the selected period. The results show that the period 2004 to 2006 and 2009 to 2010 years are observed as drought periods by both indices for almost all timescale. The intensity and duration of drought have increased after 2004. A negative trend of both the indices have been observed in all seasons on all timescale, which clearly shows a transition from near normal to moderately dry during the selected time period. The highest correlation between both the indices is for the 12-month scale with R² value 0.92 and the RMSE value 0.28. The main outcome of this study is that both SPI and SPEI show a strong correlation on same time scales adopted in this study. The dependency of SPEI on temperature is also observed in this study. Doi: 10.28991/cej-2021-03091783 Full Text: PDF

DROUGHT ASSESSMENT USING THE RECONNAISSANCE DROUGHT INDEX (RDI): A CASE STUDY OF EASTERN MEDITERRANEAN, SEYHAN, CEYHAN AND ASI BASINS OF TURKEY

In this study, drought analysis was carried out in the region, which includes the Eastern Mediterranean, Seyhan, Ceyhan and Asi Basins located in the south of Turkey. In total, data from 35 meteorological stations has been analyzed. As a drought index, the Reconnaissance Drought Index (RDI) was utilised. The Thornthwaite method was selected in the calculation of Potential Evapotranspiration (PET). According to the results, the PET values of all stations have increased in recent years. 3, 6, 9, and 12 month RDI values have been plotted based on the hydrological years. As stated by RDI results, there was mild drought in the basin. The drought results obtained by Turkish State Meteorological Service (The Ministry of Agriculture and Forestry General Directorate of Meteorology) with the Standardized Precipitation Index (SPI) method were compared with the results in this study. In this study, drought mapping for RDI was carried out using the annual values of stations with common observation years to monitor visually spatial spread of the drought.

Climatological water balance and climate classification of thornthwaite and mather for benin, west Africa, in 1970-2015 period

The climate is described by the predominant atmospheric conditions in a particular region and influences several human activities. In agriculture, water availability defines the growth and yield of crops and can be obtained by the water balance. The climate classification also aids to identify suitable areas for agricultural crops. Thus, the aim of this work was to elaborate the water balance and perform the climate classification through the method of Thornthwaite and Mather (1955) for six weather stations (Bohicon, Cotonou-Airport, Kandi-Airport, Natitingou, Parakou-Airport and Savè) located in Benin, Western Africa. For the execution of this work, monthly series of precipitation and potential evapotranspiration from 1970 to 2015 were used. Once the monthly water balance of the six seasons was elaborated, it was observed that the rainy (dry) period decreases (increases) from the coast (Cotonou-Airport) to the north of Benin (Kandi-Airport) and, coincides with Boreal summer and part of autumn (Boreal winter and part of spring). Regarding the climate classification, the Cotonou-Airport station was characterized as Subhumid Megathermal climate with moderate winter deficit (C2wA’a’); the stations of Bohicon and Savè presented similar climate classification with Subhumid Dry Megathermal climate with low or without water surplus (C1dA’a’); Natitingou with Subhumid Dry climate Megathermal with large summer surplus (C1s2A’a’); Parakou-Airport with Subhumid climate Dry Megathermic with moderate summer surplus (C1sA’a’) and, Kandi-Airport presented Semi-arid Megathermal climate with moderate summer surplus (DsA’a’). In Benin, subsistence and rainfed farming showed greater risk in the north of the country due to the decrease in the rainy season and the water surplus from the coast (south) to the north of the country, with the increase in aridity.

Assessing the agroclimatic potentiality in Indian Sundarbans for crop planning by analyzing rainfall time series data


 In order to assess the climatological risk in terms of the dry week probabilities and length of the growing period of Indian Sundarbans region for successful crop planning, the present study was conducted using long term rainfall data from 1984 to 2018 received in Gosaba CD (Community Development) block of Indian Sundarbans. The probability of a rainfall events with 25 %, 50%, 75 % probabilities were estimated. Markov Chain model was used to estimate the initial, conditional probabilities of dry and wet weeks along with the probability of two consecutive wet and dry weeks considering 10 mm and 20 mm rainfall thresholds. Length of growing period (LGP) was calculated using Moisture adequacy index computed by the soil water balance method of Thornthwaite and Mather. Weekly rainfall varied from 1.11 mm in 51st Standard Meteorological Week (SMW) with standard deviation of ± 3.41 to 88.49 mm in 29th SMW with standard deviation of ± 58.19.50 % chance of getting more than 20 mm and 10 mm weekly rainfall was observed from 20th (23.37 mm) to 41st SMW (30.64 mm) and 17th (14.63 mm) to 42nd SMW (16.87 mm) respectively. The risk of dry spells was very higher from 42nd to 17th SMW. Average LGP of the study area was 237.4 days with standard deviation of ± 29.88.Probability of a week being stress free growing period and moderately drought period was more than 50 % from 18th to 48th SMW and 49th to 5th SMW respectively. Grass pea, potato with straw mulch and green gram can be included in the rice based cropping system during winter and summer seasons for sustainable intensification of the cropping systems in Indian Sundarbans region.

BALANÇO HÍDRICO CLIMATOLÓGICO E CLASSIFICAÇÃO CLIMÁTICA PARA O MUNICÍPIO DE PARANAVAÍ, PARANÁ

The study of climatic conditions of Paranavaí region is necessary due to its importance in the national agricultural scenario. The study aimed to calculate the climatological water balance (CWB) as well as performing the climate classification by the method of Thornthwaite e Mather for the municipality of Paranavaí, Paraná. Data from a historical series from 1975 to 2018 were used. For the calculation of the CWB was adopted the value of 100 mm for the available water capacity (AWC). The municipality studied presentes na annual average of 1523,8 mm precipitation and 1090,62 evapotranspiration. The municipality presented a trend climate o fone month of water deficiency (August) and eleven months of water excess (Setember to July). Regarding climate classification, was found C1dA’a’ climate, characterized as a mesothermic climate, with little or no water deficiency.

Thornthwaite and Mather water balance method in Indonesian Tropical Area

The Thornthwaite and Mather water balance method has been widely applied in the world, one of which is in Indonesia. However, almost all studies using the Thornthwaite and Mather water balance method in Indonesia are not validated. Considering that the Thornthwaite and Mather water balance study makes it easier to study hydrology, especially in areas that do not yet have complete and evenly distributed hydrological and meteorological stations. The research locations are in the Wampu sub-watershed, Serayu sub-watershed, Ayung sub-watershed, and Tondano sub-watershed. The method used is the Thornthwaite and Mather water balance with input data on rainfall, temperature, land use, latitude, and soil texture. The validation test was performed using the RMSE equation from the runoff model compared to the observation runoff (river discharge data). The RMSE results of the Thornthwaite and Mather water balance method in the Ayung sub-watershed (42.42%), Serayu sub-watershed (53.77) Wampu sub-watershed (65.58%) and Tondano sub-watershed (83.68%) were classified as weak correlation categories. The comparison results of the Thornthwaite method in tropical areas had greater rain, potential evapotranspiration, and runoff values than other climatic areas. Based on the result, we need to modify the Thornthwaite and Mather method for tropical areas and add a range of 25-30 years of climate data.

High-resolution Data Based Groundwater Recharge Estimations of Aynalem Well Field

Due to the ever-increasing demand for water in Aynalem catchment and its surrounding, there has been an increased pressure on the Aynalem well field putting the sustainability of water supply from the aquifer under continuous threat. Thus, it is vital to understand the water balance of the catchment to ensure sustainable utilization of the groundwater resource. This in turn requires proper quantification of the components of water balance among which recharge estimation is the most important. This paper estimates the groundwater recharge of the Aynalem catchment using high-resolution hydro-meteorological data. Daily precipitation and temperature measurement data for years 2001-2018; groundwater level fluctuation records collected at every 30 minutes; and soil and land use maps were used to make recharge estimations. In the groundwater level fluctuation, three boreholes were monitored, but only two were utilized for the analysis because the third was under operation and does not represent the natural hydrologic condition. Thornthwaite soil moisture balance and groundwater level fluctuation methods were applied to determine the groundwater recharge of the Aynalem catchment. Accordingly, the annual rate of groundwater recharge estimated based on the soil-water balance ranges between 7mm/year and 138.5 mm/year with the weighted average value of 89.04 mm/year. The weighted average value is considered to represent the catchment value because the diverse soil and land use/cover types respond differently to allow the precipitation to recharge the groundwater. On the other hand, the groundwater recharge estimated using the groundwater level fluctuation method showed yearly groundwater recharge of 91 to 93 mm/year. The similarity in the groundwater recharge result obtained from both methods strengthens the acceptability of the estimate. It also points out that the previously reported estimate is much lower (36 to 66 mm/year).

A note on some uncertainties associated with Thornthwaite's aridity index introduced by using different potential evapotranspiration methods

Potential evapotranspiration (PET) is a key parameter for climate classification and aridity assessment. The widely used UNEP (1992) classification system is based on the estimation of the aridity index AI, which requires annual average values of precipitation P and PET. For the calculation of PET the Thornthwaite's (1948) formula is, in principle, suggested. Recent studies use more advanced and accurate methods for PET estimation but apply to AI the same thresholds proposed by UNEP for aridity classification. This work deals with the uncertainties introduced by the use of different PET methods in the estimation of the aridity index AI. Specifically, the Hargreaves-Samani (HS) method and four of its modifications, three modifications of Thornthwaite's formula and the equation of Hamon, are evaluated against the widely used Thornthwaite's original method, by assessing their impact on the AI. Climatic data as monthly average values of at least 30 years of measurements from 122 stations in the Greek peninsula are used. Results show that AI is highly affected by the PET method adopted, resulting thus to changes in climatic classification of a region. Further, results imply the need for an adjustment of the threshold values that determine aridity classes according to the method each time adopted. Therefore, new threshold values for the aridity classes are developed and presented in this work. The proposed threshold values cover a range of sites that belong to semi-arid SA, sub-humid SH and humid H aridity classes of the Greek peninsula.

Performance Evaluation of a Two-Parameters Monthly Rainfall-Runoff Model in the Southern Basin of Thailand

Accurate monthly runoff estimation is crucial in water resources management, planning, and development, preventing and reducing water-related problems, such as flooding and droughts. This article evaluates the monthly hydrological rainfall-runoff model’s performance, the GR2M model, in Thailand’s southern basins. The GR2M model requires only two parameters: production store (X1) and groundwater exchange rate (X2). Moreover, no prior research has been reported on its application in this region. The 37 runoff stations, which are located in three sub-watersheds of Thailand’s southern region, namely; Thale Sap Songkhla, Peninsular-East Coast, and Peninsular-West Coast, were selected as study cases. The available monthly hydrological data of runoff, rainfall, air temperature from the Royal Irrigation Department (RID) and the Thai Meteorological Department (TMD) were collected and analyzed. The Thornthwaite method was utilized for the determination of evapotranspiration. The model’s performance was conducted using three statistical indices: Nash–Sutcliffe Efficiency (NSE), Correlation Coefficient (r), and Overall Index (OI). The model’s calibration results for 37 runoff stations gave the average NSE, r, and OI of 0.657, 0.825, and 0.757, respectively. Moreover, the NSE, r, and OI values for the model’s verification were 0.472, 0.750, and 0.639, respectively. Hence, the GR2M model was qualified and reliable to apply for determining monthly runoff variation in this region. The spatial distribution of production store (X1) and groundwater exchange rate (X2) values was conducted using the IDW method. It was susceptible to the X1, and X2 values of approximately more than 0.90, gave the higher model’s performance.

Effects of Hydro-Meteorological Factors on Streamflow Withdrawal for Irrigation in Yeongsan River Basin

The relationships between a variety of hydro-meteorological variables and irrigation water use rates (WUR) were investigated in this study. Standardized Precipitation Index (SPI), Potential Evapotranspiration (PET), and Normalized Difference Vegetation Index (NDVI) were explored to identify the relationship with the WUR. The Yeongsan river basin, the agricultural land of which is mostly occupied by well-irrigated paddy, was used for the pilot study. Four different temporal scales of SPI-3, 6, 9, and 12 were tested, and PET was calculated using the Thornthwaite method. To calculate NDVI, the surface spectral reflectance data, which was acquired by Moderate Resolution Imaging Spectroradiometer (MODIS) equipped on the Terra satellite, were used. As a result, there was a statistically significant relationship between SPI9 and the WUR during drought periods in which negative values of SPI9 were obtained. The WUR was strongly correlated with both PET and NDVI. Compared with SPI, the variability of WUR in this study area was more sensitively affected by PET and NDVI, which can cause a potential lack of agricultural water supply. The finding of this study implies that SPI9, PET, and NDVI are the critical factors for predicting water withdrawal during drought conditions so that they can be used for irrigational water use management. Although a part of the findings of this study has been discussed by a few previous studies, this study is novel in that it quantifies the relationship between these factors using actual field observations of streamflow withdrawal for irrigation.

Climate risk to peanut cultivation in Brazil across different planting seasons.

Peanuts are widely grown in Brazil because of their great importance in the domestic vegetable oil industry and the succession of sugarcane, soybean and maize crops, contributing to soil conservation and improvement in agricultural areas. Thus, the present study aimed to determine the zoning of peanuts' climatic risk by estimating the water requirement satisfaction index (WRSI) for the crop in Brazil. We used a historical series of data on average air temperature and rainfall between 1980 and 2016. Reference evapotranspiration was estimated using the method of Thornthwaite, and we subsequently calculated crop evapotranspiration and maximum evapotranspiration. Water balances for all stations were calculated using the method of Thornthwaite and Mather, with an available water capacity in the soil of 15, 30 and 45 mm. The definitions of suitable, unfit and restricted areas and the planting season were performed using the WRSI. Brazil has low climatic risk areas for growing peanuts throughout the year, except for winter. The country reveals that 88.19%, 97.93%, 99.16% and 39.25% of its area is suitable for planting peanuts on planting dates in spring, summer, autumn and winter, respectively. Brazil has a large part of the areas favorable to the planting of peanuts. The maximum availability of soil water at a depth of 15, 30 and 45 mm does not influence regions with respect to peanut growing in Brazil. The states of Piauí, Ceará and Bahia are the most unsuitable on the winter planting date, with an average WRSI of 0.22. © 2021 Society of Chemical Industry.

Measurement of Some Climatic Parameter in Babylon Governorate by Statistical and Mathematical Methods

Evaporation transpiration is one of the most important results in the water balance equation for any natural area or water body, and it is also a critical component of the hydrological cycle. The relationship between temperature and transpiration was obtained using the Thornthwaite method in three stations along with Babylon Governorate. The data for the three meteorological stations were taken for 10 years. The value of climate change was obtained within the study area, including temperature, evaporation, humidity, and rainfall. The value of potential evapotranspiration was calculated by the Thornthwaite method, and the highest value was obtained in July (421.9), and the lowest value in January (3.66). Also, the increase in water was calculated for a study area. It appeared that the increase in evapotranspiration and decrease was in direct relationship with the temperature intensity of the study area.

Spatiotemporal Characteristics and Trend Analysis of Two Evapotranspiration-Based Drought Products and Their Mechanisms in Sub-Saharan Africa

Drought severity still remains a serious concern across Sub-Saharan Africa (SSA) due to its destructive impact on multiple sectors of society. In this study, the interannual variability and trends in the changes of the self-calibrating Palmer Drought Severity Index (scPDSI) based on the Penman–Monteith (scPDSIPM) and Thornthwaite (scPDSITH) methods for measuring potential evapotranspiration (PET), precipitation (P), normalized difference vegetation index (NDVI), and sea surface temperature (SST) anomalies were investigated through statistical analysis of modeled and remote sensing data. It was shown that scPDSIPM and scPDSITH differed in the representation of drought characteristics over SSA. The regional trend magnitudes of scPDSI in SSA were 0.69 (scPDSIPM) and 0.2 mm/decade (scPDSITH), with a difference in values attributed to the choice of PET measuring method used. The scPDSI and remotely sensed-based anomalies of P and NDVI showed wetting and drying trends over the period 1980–2012 with coefficients of trend magnitudes of 0.12 mm/decade (0.002 mm/decade). The trend analysis showed increased drought events in the semi-arid and arid regions of SSA over the same period. A correlation analysis revealed a strong relationship between the choice of PET measuring method and both P and NDVI anomalies for monsoon and pre-monsoon seasons. The correlation analysis of the choice of PET measuring method with SST anomalies indicated significant positive and negative relationships. This study has demonstrated the applicability of multiple data sources for drought assessment and provides useful information for regional drought predictability and mitigation strategies.

Testing Evapotranspiration Estimates Based on MODIS Satellite Data in the Assessment of the Groundwater Recharge of Karst Aquifers in Southern Italy

In many Italian regions, and particularly in southern Italy, karst aquifers are the main sources of drinking water and play a crucial role in the socio-economic development of the territory. Hence, estimating the groundwater recharge of these aquifers is a fundamental task for the proper management of water resources, while also considering the impacts of climate changes. In the southern Apennines, the assessment of hydrological parameters that is needed for the estimation of groundwater recharge is a challenging issue, especially for the spatial and temporal inhomogeneity of networks of rain and air temperature stations, as well as the variable geomorphological features and land use across mountainous karst areas. In such a framework, the integration of terrestrial and remotely sensed data is a promising approach to limit these uncertainties. In this research, estimations of actual evapotranspiration and groundwater recharge using remotely sensed data gathered by the Moderate Resolution Imaging Spectrometer (MODIS) satellite in the period 2000–2014 are shown for karst aquifers of the southern Apennines. To assess the uncertainties affecting conventional methods based on empirical formulas, the values estimated by the MODIS dataset were compared with those calculated by Coutagne, Turc, and Thornthwaite classical empirical formulas, which were based on the recordings of meteorological stations. The annual rainfall time series of 266 rain gauges and 150 air temperature stations, recorded using meteorological networks managed by public agencies in the period 2000–2014, were considered for reconstructing the regional distributed models of actual evapotranspiration (AET) and groundwater recharge. Considering the MODIS AET, the mean annual groundwater recharge for karst aquifers was estimated to be about 448 mm·year−1. In contrast, using the Turc, Coutagne, and Thornthwaite methods, it was estimated as being 494, 533, and 437 mm·year−1, respectively. The obtained results open a new methodological perspective for the assessment of the groundwater recharge of karst aquifers at the regional and mean annual scales, allowing for limiting uncertainties and taking into account a spatial resolution greater than that of the existing meteorological networks. Among the most relevant results obtained via the comparison of classical approaches used for estimating evapotranspiration is the good matching of the actual evapotranspiration estimated using MODIS data with the potential evapotranspiration estimated using the Thornthwaite formula. This result was considered linked to the availability of soil moisture for the evapotranspiration demand due to the relevant precipitation in the area, the general occurrence of soils covering karst aquifers, and the dense vegetation.