Spatial estimation of sub-hour Global Horizontal Irradiance based on official observations and remote sensors.

Federico-Vladimir Gutierrez-Corea,María-Pilar Moreno-Regidor,Miguel-Angel Manso-Callejo,Jesús Velasco-Gómez

doi:10.3390/s140406758

Federico-Vladimir Gutierrez-Corea, María-Pilar Moreno-Regidor + Show 2 more

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https://doi.org/10.3390/s140406758

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Abstract

This study was motivated by the need to improve densification of Global Horizontal Irradiance (GHI) observations, increasing the number of surface weather stations that observe it, using sensors with a sub-hour periodicity and examining the methods of spatial GHI estimation (by interpolation) with that periodicity in other locations. The aim of the present research project is to analyze the goodness of 15-minute GHI spatial estimations for five methods in the territory of Spain (three geo-statistical interpolation methods, one deterministic method and the HelioSat2 method, which is based on satellite images). The research concludes that, when the work area has adequate station density, the best method for estimating GHI every 15 min is Regression Kriging interpolation using GHI estimated from satellite images as one of the input variables. On the contrary, when station density is low, the best method is estimating GHI directly from satellite images. A comparison between the GHI observed by volunteer stations and the estimation model applied concludes that 67% of the volunteer stations analyzed present values within the margin of error (average of ±2 standard deviations).

Highlights

Global Horizontal Irradiance (GHI) sensors are especially relevant as a source of information for calculating numerous ecological and industrial processes and has other applications including model verification, data inference and data assimilation within models in contexts such as meteorology, climate or hydrology, among other fields of study
The selection of the best spatial estimation method for GHI at 15-minute intervals, evaluated in this study depend on the density of stations that observe this variable over a determined area
When the area of interest is adequately covered by ground station sensors, the best method is Regression Kriging (RK), supported by GHI values derived from satellite images and the latitude of the stations’ locations (RK2)

Summary

Introduction

Global Horizontal Irradiance (GHI) sensors are especially relevant as a source of information for calculating numerous ecological and industrial processes (i.e., photosynthesis, evaporation-transpiration, solar energy production, monitoring SmartCities [1]) and has other applications including model verification, data inference and data assimilation within models in contexts such as meteorology, climate or hydrology, among other fields of study. Solar Radiation (SR) on the Earth’s surface may be measured through direct on-site observation or estimated using an indirect method. Direct observations are made by SR sensors installed in weather stations; their scarce spatial densification presents a disadvantage. Indirect sources for estimating SR include deriving this information from satellites, determining it based on other meteorological variables and applying spatial interpolation algorithms of point values, among others [5,6]

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