Estimation of solar radiation over Cambodia from long-term satellite data

doi:10.1016/j.renene.2010.09.023

Renewable Energy

Volume 36, Issue 4, April 2011, Pages 1214-1220

https://doi.org/10.1016/j.renene.2010.09.023 Get rights and content

Abstract

In this work, monthly average daily global solar irradiation over Cambodia was estimated from a long-term satellite data. A 14-year period (1995–2008) of visible channel data from GMS5, GOES9 and MTSAT-1R satellites were used to provide earth-atmospheric reflectivity. A satellite-based solar radiation model developed for a tropical environment was used to estimate surface solar radiation. The model relates the satellite-derived earth-atmospheric reflectivity to absorption and scattering coefficients of various atmospheric constituents. The absorption of solar radiation due to water vapour was calculated from precipitable water derived from ambient relative humidity and temperature. Ozone data from the TOMS and OMI satellite data were employed to compute the solar radiation absorption by ozone. The depletion of radiation due to aerosols was estimated from the visibility data. Five new solar radiation measuring stations were established at Cambodian cities, namely Siem Reap (13.87°N, 103.85°E), Kompong Thom (12.68°N, 104.88°E), Phnom Penh (11.55°N, 104.83°E), Sihanouke Ville (10.67°N, 103.63°E) and Kampot (10.70°N, 104.28°E). Global solar radiation measured at these stations was used to validate the model. The validation was also carried out by using solar radiation measured at four Thai meteorological stations. These stations are situated near the Cambodian border. Monthly average daily global irradiation from these stations was compared with that calculated from the model. The measured and calculated irradiation is in good agreement, with the root mean square difference of 6.3%, with respect to the mean values. After the validation, the model was used to calculate monthly average daily global solar irradiation over Cambodia. Based on this satellite-derived irradiation, solar radiation maps for Cambodia were generated. These maps show that solar radiation climate of this country is strongly influenced by the monsoons. A solar radiation database was also generated for solar energy applications in Cambodia.

Introduction

The amount of solar radiation incident on the earth’s surface is an important information for designing solar energy systems such as solar cells, solar water heaters and solar crop dryers as well as solar passive systems. As solar radiation has diurnal, seasonal and inter-annual variations, long-term solar radiation data are usually required for solar energy system design. Ideally, solar radiation data from the measurements at the site where the systems are intended to build should be used for designing solar energy systems. However, in reality, such data are usually not available and the radiation data from the nearest solar radiation measuring station are employed. An accurate system design is obtained if the density of the measuring stations is high enough to detect the spatial variation of solar radiation. Due to equipment and maintenance costs, the numbers and density of the stations in developing countries are usually far too low to provide sufficient solar radiation data. As an alternative, satellite data can be used to derive solar radiation data, with a reasonable accuracy, especially for a long-term average global radiation. In the past 20 years, a number of satellite-based solar radiation models have been developed with a variety of complexities and accuracies [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30].

For the case of Cambodia, there is great demand of solar radiation data for solar energy applications, however, there is no systematic solar radiation measurement in this country. Therefore, in this work we proposed to generate solar radiation data from long-term satellite data by using a satellite-based radiation model and five solar radiation measuring stations were established for validation of the model and for long-term systematic radiation measurement in this country.

Section snippets

Preparation of satellite data

A 14-year period of 8 bit digital hourly data taken at 8:30, 9:30, 10:30, 11:30, 12:30, 13:30, 14:30 and 15:30 h local time from the visible channel of 3 geostationary satellites namely, GMS5 (June, 1995–May, 2003), GOES9 (June, 2003–July, 2005) and MTSAT-1R (August, 2005–December, 2008), were used in this work. These data displayed as image cover the entire area of Cambodia with a spatial resolution of 3 × 3 km². These images originally in satellite projection were transformed to the cylindrical

Description of the satellite-based radiation model

The model used in this work was originally developed for estimating solar radiation over the tropical western Pacific Ocean [12]. Then it was modified and applied for the tropical environment of Thailand [15]. The model was again improved to account for the upwelling aerosol absorption and effect of the terrain height [29]. This version was selected for this work, because it performed well for several tropical regions especially in South-east Asia. The description of this version is described

Validation of the model

As prior to this work there is no systematic solar radiation measurement in Cambodia, we established five new solar radiation measuring stations at 5 Cambodian cities, namely Siem Reap (13.87°N, 103.85°E), Kompong Thom (12.68°N, 104.88°E), Phnom Penh (11.55°N, 104.83°E), Sihanouke Ville (10.67°N, 103.63°E) and Kampot (10.70°N, 104.28°E). Global solar radiation was measured by Kipp&Zonen (CM11) pyranometers and solar radiation measured at these stations for the period: September, 2007–December,

Results and discussion

A 14-year period (1995–2008) of satellite and ancillary data were used to derive monthly average daily global irradiation. For each month, values of this irradiation were again averaged over the period of 14 years to obtain long-term average daily irradiation. The results were displayed as maps showing geographical distribution of monthly average daily solar irradiation over the country (Fig. 5). The yearly average of daily global irradiation maps is shown in Fig. 6.

From monthly solar radiation

Conclusion

A satellite-based model has been used to estimate monthly average daily global solar irradiation in Cambodia. Long-term observations of ground-based meteorological data and the satellite data for period between June, 1995 and December, 2008 were used as input of the model. Parameterization of the model considers reflection of clouds, absorption and scattering of solar radiation due to aerosols, ozone, water vapour, and gases. The earth-atmospheric reflectivity and ground albedo were estimated

Acknowledgments

The authors are grateful to the Department of Alternative Energy Development and Efficiency, Ministry of Energy of Thailand for inviting Silpakorn University to carry out this project and the permission to publish this work. The authors are also grateful to HE. Dr. Sat Samy, Deputy General Directorate, Ministry of Industry Mines and Energy of Cambodia for supporting this collaboration project. The authors would like to thank Mr. Toch Sovanna, Mr. So Veasna from the Department of Energy

References (33)

H.G. Beyer et al.
Modifications of the heliosat procedure for irradiance estimates from satellite images
Solar Energy
(1996)
D. Cano et al.
A method for the determination of the global solar radiation from meteorological satellite data
Solar Energy
(1986)
G. Czeplak et al.
An assessment of a statistical method to estimate solar irradiance, at the earth’s surface from geostationary satellite data
Renewable Energy
(1991)
L. Diabate et al.
Description of an operation tool for determining global solar radiation at ground using geostationary satellite images
Solar Energy
(1989)
A. Hammer et al.
Short-term forecasting of solar radiation: a statistical approach using satellite data
Solar Energy
(1999)
S. Janjai et al.
Development of a method for generating operational solar radiation maps from satellite data for a tropical environment
Solar Energy
(2005)
R. Perez et al.
A new operational for satellite-derived irradiances: description and validation
Solar Energy
(2002)
R. Perez et al.
Producing satellite-derived irradiances in complex arid terrain
Solar Energy
(2004)
C. Schillings et al.
Operational method for deriving high resolution direct normal irradiance from satellite data
Solar Energy
(2004)
C. Sorapipatana et al.
A bispectral method for determining global solar radiation from meteorological satellite data
Solar and Wind Technology
(1988)

C. Sorapipatana et al.

Mesoscale mapping of daily insolation over Southeast Asia from satellite data

Solar and Wind Technology

(1989)

F. Vignola et al.

Analysis of satellite derived beam and global solar radiation data

Solar Energy

(2007)

K. Wyser et al.

Remote sensing of surface solar irradiance with corrections for 3-D cloud effects

Remote Sensing of Environment

(2002)

A.Q. Malik et al.

Solar mapping of Pakistan using visible images from geostationary satellites

Renewable Energy

(1998)

M. Chaabane et al.

Use of HR Meteosat images for the mapping of global solar irradiation in Tunisia: preliminary results and comparison with Wefax image

Renewable Energy

(2002)

G. Dedieu et al.

Satellite estimation of solar irradiance at the surface of the earth and surface albedo using a physical model applied to METEOSAT data

Journal of Climate and Applied Meteorology

(1987)

Cited by (63)

Recent advances in the role of dissolved organic matter during antibiotics photodegradation in the aquatic environment
2024, Science of the Total Environment
The presence of residual antibiotics in the environment is a prominent issue. Photodegradation behavior is an important way of antibiotics reduction, which is closely related to dissolved organic matter (DOM) in water. The review provides an overview of the latest advancements in the field. Classification, characterization of DOM, and the dominant mechanisms for antibiotic photodegradation were discussed. Furthermore, it summarized and compared the effects of DOM on different antibiotics photodegradation. Moreover, the review comprehensively considered the factors influencing the photodegradation of antibiotics in the aquatic environment, including the characteristics of light, temperature, dosage of DOM, concentration of antibiotics, solution pH, and the presence of coexisting ions. Finally, potential directions were proposed for the development of predictive models for the photodegradation of antibiotics. Based on the review of existing literature, this paper also considered several pathways for the future study of antibiotic photodegradation. This study allows for a better understanding of the DOM's environmental role and provides important new insights into the photochemical fate of antibiotics in the aquatic environment.
Daily global solar radiation time series prediction using variational mode decomposition combined with multi-functional recurrent fuzzy neural network and quantile regression forests algorithm
2023, Energy Reports
Global solar radiation (GSR) prediction capability with a reliable model and high accuracy is crucial for comprehending hydrological and meteorological systems. It is vital for the production of renewable and clean energy. This research aims to evaluate the performance of combined variational mode decomposition (VMD) with a multi-functional recurrent fuzzy neural network (MFRFNN) and quantile regression forests (QRF) models for GSR prediction in daily scales. The hybrid VMD-MFRFNN and QRF models were compared with standalone MFRFNN, random forest (RF), extreme gradient boosting (XGB), and M5 tree (M5T) models across the Lund and Växjö meteorological stations in Sweden. The meteorological data from 2008 to 2017 were used to train the models, while the prediction accuracy was verified by using the data from 2018 to 2021 under five different input combinations. The various meteorological-based scenarios (including the input are air temperatures (Tmin, Tmax, T), wind speed (WS), relative humidity (RH), sunshine duration (SSH), and maximum possible sunshine duration (N)) were considered as input of predictor models. The current study resulted that the M5T model exhibited higher accuracy than RF and XGB models, while the QRF model showed equivalent performance with the M5T model at both study sites. The MFRFNN model outperformed QRF and M5T models across all input combinations at both study sites. The hybrid VMD-MFRFNN model showed the best performance when fewer input variables (Tmin, Tmax, T, WS at Lund station and Tmin, Tmax, T, WS, SSH, RH at Växjö station) were used for GSR prediction. We conclude that the MFRFNN model best predicts average daily GSR when combining all meteorological variables (Tmin, Tmax, T, WS, SSH, RH, N).
Photochemical behaviors of dissolved organic matter in aquatic environment: Generation, characterization, influencing factors and practical application
2023, Environmental Research
Dissolved organic matter (DOM) widely exists in aquatic environment and plays a critical role in environmental photochemical reaction. The photochemical behaviors of DOM in sunlit surface waters have received widely attention because its photochemical effects for some coexisted substances in aquatic environment, especially for organic micropollutants degradation. Therefore, to gain a comprehensive understanding of the photochemical properties and environmental effects of DOM, we reviewed the influence of sources on the structure and composition of DOM with relevant identified techniques to analysis functional groups. Additionally, identification and quantification for reactive intermediates are discussed with a focus on influencing factors to produce reactive intermediates by DOM under solar irradiation. These reactive intermediates can promote the photodegradation of organic micropollutants in the environmental system. In future, attention should be paid to the photochemical properties of DOM and environmental effects in real environmental system and development of advanced techniques to study DOM.
Potential effect of atmospheric condition on incident light and photo-production of reactive intermediates in freshwater systems
2023, Environmental Advances
The effect of local atmospheric conditions on aquatic photochemical reactions has been rarely explored because of the difficulty in field observation. Thus, this study aimed to elucidate the effects of atmospheric conditions, which are inorganic air pollution, aerosol pollution, and ozone layer depletion, on the incident light and photo-production of reactive intermediates (RIs). Models of SMARTS (Simple Model for the Atmospheric Radiative Transfer of Sunshine) and APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics) were used to simulate the changes in wavelength profile and steady-state concentrations of RIs, which are hydroxyl radical, carbonate radical, singlet oxygen, and triplet-state of dissolved organic matter. Results showed that inorganic air pollution and aerosol pollution have a reduction effect on the production of RIs, while ozone layer depletion increases the production of RIs. Among them, inorganic air pollution has the largest influence on the production of RIs which were expected to reduce by 80%–90% in extreme pollution. This study also investigated the potential effect of water constituents (i.e., NO₃⁻, dissolved organic matter, and HCO₃⁻) on the relation between atmospheric conditions and the production of RIs. NO₃⁻ concentration under different atmospheric conditions showed the most influence on the production of RIs. This study highlighted the importance of considering atmospheric conditions when assessing the photochemical persistence of organic pollutants. Even though these results are model output, they quantitatively revealed the potential influence of atmospheric conditions on the production of RIs in freshwater systems.
Photodegradation of organic micropollutants in aquatic environment: Importance, factors and processes
2023, Water Research
Photochemical reactions widely occur in the aquatic environment and play fundamental roles in aquatic ecosystems. In particular, solar-induced photodegradation is efficient for many organic micropollutants (OMPs), especially those that cannot undergo hydrolysis or biodegradation, and thus can mitigate chemical pollution. Recent reports indicate that photodegradation may play a more important role than biodegradation in many OMP transformations in the aquatic environment. Photodegradation can be influenced by the water matrix such as pH, inorganic ions, and dissolved organic matter (DOM). The effect of the water matrix such as DOM on photodegradation is complex, and new insights concerning the disparate effects of DOM have recently been reported. In addition, the photodegradation process is also influenced by physical factors such as latitude, water depth, and temporal variations in sunlight as these factors determine the light conditions. However, it remains challenging to gain an overview of the importance of photodegradation in the aquatic environment because the reactions involved are diverse and complex. Therefore, this review provides a concise summary of the importance of photodegradation and the major processes related to the photodegradation of OMPs, with particular attention given to recent progress on the major reactions of DOM. In addition, major knowledge gaps in this field of environmental photochemistry are highlighted.
Integrated assessment of offshore wind power potential using Weather Research and Forecast (WRF) downscaling with Sentinel-1 satellite imagery, optimal sites, annual energy production and equivalent CO<inf>2</inf> reduction
2022, Renewable and Sustainable Energy Reviews
Citation Excerpt :
Thus, to improve system reliability, source diversification should be considered. The Cambodian potential for RES was shown in Refs. [43–45]. Furthermore, in the wind resource atlas of Southeast Asia, it was highlighted that the Krovanh Mountain range in southwestern Cambodia and the highly elevated areas near the Vietnamese border in the southeastern province of Kracheh exhibited high wind velocities [46].
This study aims to assess the offshore wind power potential in Cambodia using the WRF and Sentinel-1 level 2 ocean (L2 OCN) products, to evaluate potential sites and to estimate the annual energy production (AEP) and equivalent CO₂ reduction. The model is initially calibrated and validated against observed onshore winds at four weather stations before its main simulation for the two-years study period of 2018–2019. As a result, the spatially averaged annual wind speed errors between the WRF and L2 OCN data are 0.70 m/s for mean bias error and 0.79 m/s for root mean square error, indicating good model performance. The annual mean wind speeds over the Cambodian Sea are 5.15 m/s, 5.20 m/s and 5.27 m/s at 80 m, 100 m and 140 m above sea level, respectively. Then, analytic hierarchy process (AHP) is applied to evaluate the optimal sites for offshore wind power generation. The most potential areas in Cambodian sea are along Kampot and Kep shoreline. The resulting AEPs are 11,949.02 GWh for 80-m V112 turbines, 20,013.34 GWh for 100-m V164 turbines and 31,880.48 GWh for 150-m HX12 turbines, which could reduce CO₂ emissions by 5.48 Mt-CO₂, 9.18 Mt-CO₂ and 14.63 Mt-CO₂ per year, respectively. If 10% of the total AEP could be generated by 2030, the offshore wind source would contribute to 1.95%, 3.27%, or 5.20% of the country's electric demands forecasted for 2030. The integrated assessment methodology and resources adopted in this study can be applicable to other regions particularly where offshore measurements are not readily available.

View all citing articles on Scopus

View full text