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Register a new userEstimation of Monthly Reference Evapotranspiration in Safita Area by using Artificial Neural Network
تقدير التّبخر- نتح المرجعي الشَّهري في منطقة صافيتا باستخدام الشَّبكة العصبيَّة الصنعيَّة
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Tishreen University ورقة بحثية
Publication date
2013
fields
Structural Engineering
and research's language is
العربية
Created by
Shamra Editor
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يشكّل التبخر-نتح أحد عناصر الدورة الهيدرولوجية، الذي يصعب قياس كمياته الفعلية في الشروط الحقلية، لذلك يجري تقديره انطلاقاً من علاقات تجريبية تعتمد على بيانات عناصر المناخ، و تتضمن تلك التقديرات أخطاء متنوّعة بسبب عمليات التقريب. و يهدف البحث إلى تقدير دقيق لكمية التبخر الشهري في منطقة صافيتا, و يعتمد البحث على تقانة الشبكة العصبية الصنعية، حيث بُني الأنموذج الرياضي باستخدام Neural Fitting Tool (nftool) إحدى أدوات الماتلاب، و اعتمد الأنموذج على البيانات الشهرية لدرجة حرارة الهواء و الرطوبة النسبية في محطة صافيتا، كما استُخدِمت بيانات التبخر الشهري من حوض التبخر الأميركي صنف A لغرض التحقق من صحة أداء الشبكة، بعد تحويل الأنموذج إلى شكل قالب جاهز باستخدام تقانة Simulink المتاحة في حزمة برمجيات الماتلاب. أثبتت نتائج الدراسة أنَّ الشبكة العصبية الصنعيَّة متعددة الطبقات، و ذات الانتشار العكسي للخطأ تعطي نتائج جيدة في تقويم التبخر الشهري، اعتماداً على مجموعة البيانات المستخدَمة.
Evapotranspiration forms one of the hydrology cycle elements that it's hard to measure its actual amounts in the field conditions, so it’s estimated by calculations of experimental relations that depend on climatic elements data. These estimations include different errors because of approximation processes. The research goals to accurate estimation of the monthly reference evapotranspiration amount in Safita area (on the east coast of the Mediterranean Sea), and the research depends on the technique of Artificial Neural Network (ANN), and the mathematical model was built by the (nftool), which is one of the Matlab tools, depending on monthly air temperature and relative humidity data which were taken from Safita meteorological station, and the data of monthly pan evaporation (Class A pan) has been used, after modifying its results, for the purpose of checking the performance accuracy of the network, by using Simulink technique, which is existing in Matlab Programs Package. The results of the research verify that a multi-layer ANN of error Back-propagation algorithm gives a good result in estimating monthly reference Evapo-transpiration for the used data group.
References used
DOORENBOS, J.; PRUITT, W.O. GuideLines for Predicting Crop Water Requirement. Food and Agriculture Organization of the United Nations (FAO). N .24,1977,156
RAGHUWANSHI, N.S.; WALLENDER, W.W. Converting from pan Evaporation to Evapotranspiration. Journal of Irrigation and Drainage Engineering. Vol. 124, 1998, 275-277
FAO Corporate Document Repository. Crop Evapotranspiration. Natural Resources Management and environment Department, 2008
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Accurate estimating and predicting of hydrological phenomena plays an influential role in the development and management of water resources, preparing of future plans according to different scenarios of climate changes. Evapotranspiration is one of t
he major meteorological components of the hydrologic cycle and from the most complex of them, and the accurate prediction of this parameter is very important for many water resources applications.
So, this research goals to prediction of monthly reference evapotranspiration (ET0) at Homs meteostation, in the middle of Syrian Arab Republic, using Artificial Neural Networks (ANNs), and Fuzzy Inference System (FIS), depending on available climatic data, and comparision between the results of these models.
The used data contained 347 monthly values of Air Temperature (T), Relative Humidity (RH), Wind Speed (WS) and Sunshine Hours (SS) (from October 1974 to December 2004). The monthly reference evapotranspiration data were estimated by the Penman Monteith method, which is the proposed method by Food and Agriculture Organization of the United Nations (FAO) as the standard method for the estimation of ET0, and used as outputs of the models.
The results of this study showed that feed forward back propagation Artificial Neural Networks (FFBP-ANNs) pridected successfully the monthly ET0 using climatic data, with low values of root mean square errors (RMSE), and high values of correlation coefficients (R), and showed that the using of the monthly index as an additional input, improves the accurate of prediction of the artificial neural networks models.
Also, the results showed good ability of Fuzzy Inference Models (FIS) in predicting of monthly reference evapotranspiration. Sunshine hours are the most influential single parameter for ET0 prediction (R= 97.71%, RMSE = 18.08 mm/month) during the test period, sunshine hours and wind speed are the most influential optimal combination of two parameters
(R= 98.55%, RMSE = 12.49 mm/month) during the test period.
The results showed high reliability for each of the artificial neural networks and fuzzy inference system with a little preference for artificial neural networks which can add the monthly index in the input layer, and there for improve the presicion of predictions.
This study recommends the using of artificial intelligence techniques in modeling of complex and nonlinear phenomena which related of water resources.
Evapotranspiration is an important component of the
hydrologic cycle, and the accurate prediction of this parameter is
very important for many water resources applications. Thus, the
aim of this study is prediction of monthly reference
evapotranspiration using Artificial Neural Networks (ANNs) and
fuzzy inference system (FIS).
The evaporation is one of the basic components of the hydrologic cycle and it is
essential for studies such as water balance, irrigation system design and water resource
management, and it requires knowledge of many climatic variables. Although, th
ere are
many empirical formulas available for evaporation estimate, but their performances are not
all satisfactory due to the complicated nature of the evaporation process. Accordingly, this
paper is an attempt to assess the potential and usefulness of ANN based modeling for
evaporation prediction from HAMA by using temperature, relative humidity and wind
velocity. The mathematical model was built by the (nntool-box), which is one of the
MATLAB tools. The feed forward back propagation network with one hidden layer has
been utilised to construct the model. Different networks with different number of neurons
were evaluated. Root Mean Squared Error (RMSE) was employed to evaluate the accuracy
of the proposed model. The study shows that ANN (3-14-1) was the best model with
RMSE (21.5mm/month) and R2 (0.97).
This study suggests using other types of neural networks for estimation of
evaporation
Weather forecasting (especially rainfall) is one of the most important and challenging
operational tasks carried out by meteorological services all over the world. Itis furthermore
a complicated procedure that requires multiple specialized fields o
f expertise.
In this paper, a model based on artificial neural networks (ANNs) and wavelet Transform
is proposed as tool to predict consecutive monthly rainfalls (1933-2009) taken of
Homs Meteorological Station on accounts of the preceding events of rainfall data.
The feed-forward neural network with back-propagation Algorithm is used in the
learning and forecasting, where the time series of rain that detailed transactions and the
approximate three levels of analysis using a Discrete wavelet transform (DWT).
The study found that the neural network WNN structured )5-8-8-8-1(, able to predict
the monthly rainfall in Homs station on the long-term correlation of determination and root
mean squared-errors (0.98, 7.74mm), respectively.
Wavelet Transform technique provides a useful feature based on the analysis of the
data, which improves the performance of the model and applied this technique in ANNmodels
for rain because it is simple, as this technique can be applied to other models.
Evaporation is a major meteorological component of the hydrologic cycle, and it
plays an influential role in the development and management of water resources. The aim
of this study is to predict of the monthly pan evaporation in Homs meteostation
using
Artificial Neural Networks (ANNs), which based on monthly air temperature and relative
humidity data only as inputs, and monthly pan evaporation as output of the network. The
network was trained and verified using a back-propagation algorithm with different
learning methods, number of processing elements in the hidden layer(s), and the number of
hidden layers. Results shown good ability of (2-10-1) ANN to predict of monthly pan
evaporation with total correlation coefficient equals 96.786 % and root mean square error
equals 24.52 mm/month for the total data set. This study recommends using the artificial
neural networks approach to identify the most effective parameters to predict evaporation.
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