Short Term PV Forecasting Using Satellite Data for Austria

Author(s):  
Dominik Kortschak ◽  
Marianne Feichtinger-Hofer ◽  
Michael Kernitzkyi
Keyword(s):  
Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5865
Author(s):  
Abhnil Amtesh Prasad ◽  
Merlinde Kay

Solar energy production is affected by the attenuation of incoming irradiance from underlying clouds. Often, improvements in the short-term predictability of irradiance using satellite irradiance models can assist grid operators in managing intermittent solar-generated electricity. In this paper, we develop and test a satellite irradiance model with short-term prediction capabilities using cloud motion vectors. Near-real time visible images from Himawari-8 satellite are used to derive cloud motion vectors using optical flow estimation techniques. The cloud motion vectors are used for the advection of pixels at future time horizons for predictions of irradiance at the surface. Firstly, the pixels are converted to cloud index using the historical satellite data accounting for clear, cloudy and cloud shadow pixels. Secondly, the cloud index is mapped to the clear sky index using a historical fitting function from the respective sites. Thirdly, the predicated all-sky irradiance is derived by scaling the clear sky irradiance with a clear sky index. Finally, a power conversion model trained at each site converts irradiance to power. The prediction of solar power tested at four sites in Australia using a one-month benchmark period with 5 min ahead prediction showed that errors were less than 10% at almost 34–60% of predicted times, decreasing to 18–26% of times under live predictions, but it outperformed persistence by >50% of the days with errors <10% for all sites. Results show that increased latency in satellite images and errors resulting from the conversion of cloud index to irradiance and power can significantly affect the forecasts.


Author(s):  
Emilio Chuvieco ◽  
Michel Deshayes ◽  
Nicholas Stach ◽  
David Cocero ◽  
David Riaño

Author(s):  
Zekai Şen

In general, the techniques to predict drought include statistical regression, time series, stochastic (or probabilistic), and, lately, pattern recognition techniques. All of these techniques require that a quantitative variable be identified to define drought, with which to begin the process of prediction. In the case of agricultural drought, such a variable can be the yield (production per unit area) of the major crop in a region (Kumar, 1998; Boken, 2000). The crop yield in a year can be compared with its long-term average, and drought intensity can be classified as nil, mild, moderate, severe, or disastrous, based on the difference between the current yield and the average yield. Regression techniques estimate crop yields using yield-affecting variables. A comprehensive list of possible variables that affect yield is provided in chapter 1. Usually, the weather variables routinely available for a historical period that significantly affect the yield are included in a regression analysis. Regression techniques using weather data during a growing season produce short-term estimates (e.g., Sakamoto, 1978; Idso et al., 1979; Slabbers and Dunin, 1981; Diaz et al., 1983; Cordery and Graham, 1989; Walker, 1989; Toure et al., 1995; Kumar, 1998). Various researchers in different parts of the world (see other chapters) have developed drought indices that can also be included along with the weather variables to estimate crop yield. For example, Boken and Shaykewich (2002) modifed the Western Canada Wheat Yield Model (Walker, 1989) drought index using daily temperature and precipitation data and advanced very high resolution radiometer (AVHRR) satellite data. The modified model improved the predictive power of the wheat yield model significantly. Some satellite data-based variables that can be used to predict crop yield are described in chapters 5, 6, 9, 13, 19, and 28. The short-term estimates are available just before or around harvest time. But many times long-term estimates are required to predict drought for next year, so that long-term planning for dealing with the effects of drought can be initiated in time.


2021 ◽  
Vol 8 (1) ◽  
pp. 33
Author(s):  
Carlos Javier Gamboa-Villafruela ◽  
José Carlos Fernández-Alvarez ◽  
Maykel Márquez-Mijares ◽  
Albenis Pérez-Alarcón ◽  
Alfo José Batista-Leyva

The short-term prediction of precipitation is a difficult spatio-temporal task due to the non-uniform characterization of meteorological structures over time. Currently, neural networks such as convolutional LSTM have shown ability for the spatio-temporal prediction of complex problems. In this research, we propose an LSTM convolutional neural network (CNN-LSTM) architecture for immediate prediction of various short-term precipitation events using satellite data. The CNN-LSTM is trained with NASA Global Precipitation Measurement (GPM) precipitation data sets, each at 30-min intervals. The trained neural network model is used to predict the sixteenth precipitation data of the corresponding fifteen precipitation sequence and up to a time interval of 180 min. The results show that the increase in the number of layers, as well as in the amount of data in the training data set, improves the quality of the forecast.


2012 ◽  
Vol 25 (22) ◽  
pp. 7983-7990 ◽  
Author(s):  
Hirohiko Masunaga

Abstract In this study the observed relationship of precipitation with column relative humidity (CRH), a metric of tropospheric humidity, is examined in order to address a known discrepancy inherent to past studies. A composite analysis of satellite data is carried out to explore the short-term (i.e., from hourly to daily) atmospheric variability for comparison with the climatology, hypothesizing that a primary cause for the discrepancy arises from a difference in the time scale of interest. The analysis is broken down into four classes on the basis of the degree of convective organization, ranging from unorganized shallow cumuli to highly organized convective systems. The CRH–precipitation relationship is found to be extremely nonlinear for the short-term variability, while the nonlinearity weakens to some degree when different convective systems in diverse humidity environments are averaged together into climatology. The weak exponential rise in the climatological CRH–precipitation curve occurs because highly organized convective systems become more frequent and intense and thus receive increasing weight in the climatological mean as the environment moistens.


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