scholarly journals Implementation of Bessel's method for solar eclipses prediction in the WRF-ARW model

2016 ◽  
Vol 16 (9) ◽  
pp. 5949-5967 ◽  
Author(s):  
Alex Montornès ◽  
Bernat Codina ◽  
John W. Zack ◽  
Yolanda Sola
Keyword(s):  
Solar Radiation ◽  
Solar Eclipse ◽  
Weather Prediction ◽  
Grid Point ◽  
Absolute Error ◽  
Resource Assessment ◽  
Surface Radiation ◽  
Computational Time ◽  
Arw Model ◽  
Solar Eclipses

Abstract. Solar eclipses are predictable astronomical events that abruptly reduce the incoming solar radiation into the Earth's atmosphere, which frequently results in non-negligible changes in meteorological fields. The meteorological impacts of these events have been analyzed in many studies since the late 1960s. The recent growth in the solar energy industry has greatly increased the interest in providing more detail in the modeling of solar radiation variations in numerical weather prediction (NWP) models for the use in solar resource assessment and forecasting applications. The significant impact of the recent partial and total solar eclipses that occurred in the USA (23 October 2014) and Europe (20 March 2015) on solar power generation have provided additional motivation and interest for including these astronomical events in the current solar parameterizations.Although some studies added solar eclipse episodes within NWP codes in the 1990s and 2000s, they used eclipse parameterizations designed for a particular case study. In contrast to these earlier implementations, this paper documents a new package for the Weather Research and Forecasting–Advanced Research WRF (WRF-ARW) model that can simulate any partial, total or hybrid solar eclipse for the period 1950 to 2050 and is also extensible to a longer period. The algorithm analytically computes the trajectory of the Moon's shadow and the degree of obscuration of the solar disk at each grid point of the domain based on Bessel's method and the Five Millennium Catalog of Solar Eclipses provided by NASA, with a negligible computational time. Then, the incoming radiation is modified accordingly at each grid point of the domain.This contribution is divided in three parts. First, the implementation of Bessel's method is validated for solar eclipses in the period 1950–2050, by comparing the shadow trajectory with values provided by NASA. Latitude and longitude are determined with a bias lower than 5  ×  10−3 degrees (i.e.,  ∼  550 m at the Equator) and are slightly overestimated and underestimated, respectively. The second part includes a validation of the simulated global horizontal irradiance (GHI) for four total solar eclipses with measurements from the Baseline Surface Radiation Network (BSRN). The results show an improvement in mean absolute error (MAE) from 77 to 90 % under cloudless skies. Lower agreement between modeled and measured GHI is observed under cloudy conditions because the effect of clouds is not included in the simulations for a better analysis of the eclipse outcomes. Finally, an introductory discussion of eclipse-induced perturbations in the surface meteorological fields (e.g., temperature, wind speed) is provided by comparing the WRF–eclipse outcomes with control simulations.

scholarly journals Implementation of the Bessel's method for solar eclipses prediction in the WRF-ARW model

2016 ◽  
Author(s):  
A. Montornès ◽  
B. Codina ◽  
J. W. Zack ◽  
Y. Sola
Keyword(s):  
Solar Radiation ◽  
Solar Eclipse ◽  
Weather Prediction ◽  
Grid Point ◽  
Measurement Data ◽  
Surface Radiation ◽  
Computational Time ◽  
Arw Model ◽  
Solar Eclipses ◽  
The Impact

Abstract. Solar eclipses are predictable astronomical events that abruptly reduce the incoming solar radiation into the Earth's atmosphere, which frequently result in non-negligible changes in meteorological fields. The meteorological impacts of these events have been analyzed in many studies since the late 1960s. The recent growth in the solar energy industry has greatly increased the interest in adding additional detail to the modeling of solar radiation variations in Numerical Weather Prediction (NWP) models for use in solar resource assessment and forecasting applications. The recent partial and total solar eclipses that occurred in USA (October 23, 2014) and Europe (March 20, 2015), respectively, are showing the necessity for including these astronomical events on the current solar parameterizations, beyond the purely meteorological interest. Although some studies added solar eclipse episodes within NWP codes in the 1990s and 2000s, they used eclipse parameterizations designed for a particular case of study. In contrast to these earlier implementations, this paper documents a new package for the Weather Research and Forecasting – Advanced Research (WRF-ARW) model that can simulate any partial, total or hybrid solar eclipse for the period 1950 to 2050 and is also extensible to a longer period. The algorithm computes analytically the trajectory of the Moon's shadow and the degree of obscuration of the solar disk at each grid-point of the domain based on the Bessel's method and the Five Millennium Catalog of Solar Eclipses provided by NASA, with a negligible computational time. Then, the incoming radiation is modified accordingly at each grid-point of the domain. This contribution is divided in two parts. First, we present a description of the implementation of the Bessel's method within the WRF-ARW model together with a validation for the period 1950-2050 of all solar eclipse trajectories with respect to NASA values. Second, we analyze the model response in four total solar eclipse episodes: 1994-11-03 (South America), 1999-08-11 (Europe), 2006-03-29 (North Africa) and 2009-07-22 (Eastern Asia). The second part includes a validation of the simulated global horizontal irradiance (GHI) with measurement data from selected Baseline Surface Radiation Network sites within the area affected by each event as well as an analysis of the impact of the GHI changes in surface temperature and wind speed.

scholarly journals Development of a Seamless Forecast for Solar Radiation Using ANAKLIM++

2020 ◽  
Vol 12 (21) ◽  
pp. 3672
Author(s):  
Isabel Urbich ◽  
Jörg Bendix ◽  
Richard Müller
Keyword(s):  
Solar Radiation ◽  
Weather Prediction ◽  
Software Tool ◽  
Absolute Error ◽  
Shortwave Radiation ◽  
Data Sets ◽  
Climate Data ◽  
Forecast Horizon ◽  
Novel Approach ◽  
Forecasting System

A novel approach for a blending between nowcasting and numerical weather prediction (NWP) for the surface incoming shortwave radiation (SIS) for a forecast horizon of 1–5 h is presented in this study. The blending is performed with a software tool called ANAKLIM++ (Adjustment of Assimilation Software for the Reanalysis of Climate Data) which was originally designed for the efficient assimilation of two-dimensional data sets using a variational approach. A nowcasting for SIS was already presented and validated in earlier publications as seamless solar radiation forecast (SESORA). For our blending, two NWP models, namely the ICON (Icosahedral Non-hydrostatic model) from the German weather Service (DWD) and the IFS (Integrated Forecasting System) from the European Centre for Medium-Range Weather Forecasts (ECMWF), were used. The weights for the input data for ANAKLIM++ vary for every single forecast time and pixel, depending on the error growth of the nowcasting. The results look promising, since the root mean square error (RMSE) and mean absolute error (MAE) of the blending are smaller than the error measures of the nowcasting or NWP models, respectively.

scholarly journals Analysis of the ozone profile specifications in the WRF-ARW model and their impact on the simulation of direct solar radiation

2015 ◽  
Vol 15 (5) ◽  
pp. 2693-2707 ◽  
Author(s):  
A. Montornès ◽  
B. Codina ◽  
J. W. Zack
Keyword(s):  
Solar Radiation ◽  
Weather Prediction ◽  
Reanalysis Data ◽  
Direct Solar Radiation ◽  
Spatial And Temporal Variability ◽  
Data Sets ◽  
Data Set ◽  
Ozone Profile ◽  
Arw Model ◽  
The Impact

Abstract. Although ozone is an atmospheric gas with high spatial and temporal variability, mesoscale numerical weather prediction (NWP) models simplify the specification of ozone concentrations used in their shortwave schemes by using a few ozone profiles. In this paper, a two-part study is presented: (i) an evaluation of the quality of the ozone profiles provided for use with the shortwave schemes in the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model and (ii) an assessment of the impact of deficiencies in those profiles on the performance of model simulations of direct solar radiation. The first part compares simplified data sets used to specify the total ozone column in six schemes (i.e., Goddard, New Goddard, RRTMG, CAM, GFDL and Fu–Liou–Gu) with the Multi-Sensor Reanalysis data set during the period 1979–2008 examining the latitudinal, longitudinal and seasonal limitations in the ozone profile specifications of each parameterization. The results indicate that the maximum deviations are over the poles and show prominent longitudinal patterns in the departures due to the lack of representation of the patterns associated with the Brewer–Dobson circulation and the quasi-stationary features forced by the land–sea distribution, respectively. In the second part, the bias in the simulated direct solar radiation due to these deviations from the simplified spatial and temporal representation of the ozone distribution is analyzed for the New Goddard and CAM schemes using the Beer–Lambert–Bouguer law and for the GFDL using empirical equations. For radiative applications those simplifications introduce spatial and temporal biases with near-zero departures over the tropics throughout the year and increasing poleward with a maximum in the high middle latitudes during the winter of each hemisphere.

scholarly journals Predicting solar radiation using a parametric cloud model

2020 ◽  
Vol 172 ◽  
pp. 11006
Author(s):  
Kristian Skeie ◽  
Arild Gustavsen
Keyword(s):  
Solar Radiation ◽  
Cloud Model ◽  
Weather Prediction ◽  
Global Solar Radiation ◽  
Vertical Surface ◽  
Original Method ◽  
Surface Radiation ◽  
Cloud Coverage ◽  
Forecasting Performance ◽  
Nwp Model

In this paper, we evaluate a method to calculate hourly global solar radiation and improve the calculation of diffuse and vertical surface radiation on building facades by accounting for ground conditions based on publicly available data of cloud coverage, temperature and precipitation from a forecast service covering the Nordic countries. The detailed weather forecasts produced by MET Norway provide hourly forecasts for the next 60 hours, and 6-hour predictions for the next week. To calculate solar radiation on cloudy days the clear and cloudy sky MAC model developed by Davies and Mckay (1982) is used. Instead of basing the prediction on ground observations as in the original method, cloud coverage in three levels and total cloud cover is used as input in a cloud product parameterisation. The resulting global horizontal irradiance is validated against the output of the numerical weather prediction (NWP) model and compared to a year of hourly ground measurements in Trondheim, Norway. To evaluate applicability to the building sciences, vertical irradiance measurements are compared to tilted surface irradiance calculated with the ISO 52010:2017 method. For the location, six-hour forecasting performance is on par with the GHI output of the NWP model (using the cloud layer model and the available weather parameters of the location forecast API). To account for the unpredictability of clouds and improve the short-term forecasting performance beyond 38 % RMSD, 38 % SD and 0.80 R2 a different approach is needed, like combining model and sky observations.

scholarly journals Coordinated weather balloon solar radiation measurements during a solar eclipse

2016 ◽  
Vol 374 (2077) ◽  
pp. 20150221 ◽  
Author(s):  
R. G. Harrison ◽  
G. J. Marlton ◽  
P. D. Williams ◽  
K. A. Nicoll
Keyword(s):  
Solar Radiation ◽  
Solar Eclipse ◽  
Solar Limb ◽  
Mean Value ◽  
Radiation Environment ◽  
Atmospheric Effects ◽  
Sensor Platforms ◽  
Solar Eclipses ◽  
Limb Darkening ◽  
Radiation Measurements

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’.

scholarly journals The solar eclipse: a natural meteorological experiment

2016 ◽  
Vol 374 (2077) ◽  
pp. 20150225 ◽  
Author(s):  
R. Giles Harrison ◽  
Edward Hanna
Keyword(s):  
Solar Radiation ◽  
Solar Eclipse ◽  
Prediction Models ◽  
Numerical Models ◽  
Weather Prediction ◽  
Regional Scale ◽  
Electrical Energy ◽  
Atmospheric Effects ◽  
Modern Approach ◽  
Spatial Coverage

A solar eclipse provides a well-characterized reduction in solar radiation, of calculable amount and duration. This captivating natural astronomical phenomenon is ideally suited to science outreach activities, but the predictability of the change in solar radiation also provides unusual conditions for assessing the atmospheric response to a known stimulus. Modern automatic observing networks used for weather forecasting and atmospheric research have dense spatial coverage, so the quantitative meteorological responses to an eclipse can now be evaluated with excellent space and time resolution. Numerical models representing the atmosphere at high spatial resolution can also be used to predict eclipse-related changes and interpret the observations. Combining the models with measurements yields the elements of a controlled atmospheric experiment on a regional scale (10–1000 km), which is almost impossible to achieve by other means. This modern approach to ‘eclipse meteorology’ as identified here can ultimately improve weather prediction models and be used to plan for transient reductions in renewable electricity generation. During the 20 March 2015 eclipse, UK electrical energy demand increased by about 3 GWh (11 TJ) or about 4%, alongside reductions in the wind and photovoltaic electrical energy generation of 1.5 GWh (5.5 TJ). This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’.

scholarly journals Analysis of the ozone profile specifications in the WRF-ARW model and their impact on the simulation of direct solar radiation

2014 ◽  
Vol 14 (14) ◽  
pp. 20231-20257
Author(s):  
A. Montornès ◽  
B. Codina ◽  
J. W. Zack
Keyword(s):  
Solar Radiation ◽  
Weather Prediction ◽  
Direct Solar Radiation ◽  
Spatial And Temporal Variability ◽  
Reanalysis Dataset ◽  
Temporal Representation ◽  
Middle Latitudes ◽  
Ozone Profile ◽  
Arw Model ◽  
The Impact

Abstract. Although ozone is an atmospheric gas with high spatial and temporal variability, mesoscale numerical weather prediction (NWP) models simplify the specification of ozone concentrations used in their shortwave schemes by using a few ozone profiles. In this paper, a two-part study is presented: (i) an assessment of the quality of the ozone profiles provided for use with the shortwave schemes in the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model and (ii) the impact of deficiencies in those profiles on the performance of model simulations of direct solar radiation. The first part compares simplified datasets used to specify the total ozone column in five schemes (i.e. Goddard, New Goddard, RRTMG, CAM and Fu–Liou–Gu) with the Multi-Sensor Reanalysis dataset during the period 1979–2008 examining the latitudinal, longitudinal and seasonal limitations in the ozone modeling of each parameterization. The results indicate that the maximum deviations are over the poles due to the Brewer–Dobson circulation and there are prominent longitudinal patterns in the departures due to quasi-stationary features forced by the land–sea distribution. In the second part, the bias in the simulated direct solar radiation due to these deviations from the simplified spatial and temporal representation of the ozone distribution is analyzed for the New Goddard and CAM schemes using the Beer–Lambert–Bouger law. For radiative applications those simplifications introduce spatial and temporal biases with near-zero departures over the tropics during all the year and increasing poleward with a maximum in the high middle latitudes during the winter of each hemisphere.

Assessing the WRF-Solar model performance using satellite-derived irradiance from the National Solar Radiation Database

2021 ◽  
Author(s):  
Jaemo Yang ◽  
Ju-Hye Kim ◽  
Manajit Sengupta ◽  
Jimy Dudhia
Keyword(s):  
Solar Radiation ◽  
Weather Prediction ◽  
Model Performance ◽  
Absolute Error ◽  
Forecast Errors ◽  
Grid Spacing ◽  
Radiative Effects ◽  
High Quality ◽  
Radiation Processes ◽  
Nwp Model

Abstract WRF-Solar is a numerical weather prediction (NWP) model specifically designed to meet the increasing demand for accurate solar irradiance forecasting. The model provides flexibility in the representation of the aerosol-cloud-radiation processes. This flexibility can be argued to make more difficult to improve the model’s performance due to the necessity of inspecting different configurations. To alleviate this, WRF-Solar has a reference configuration to use it as a benchmark in sensitivity experiments. However, the scarcity of high-quality ground observations is a handicap to accurately quantify the model performance. An alternative to ground observations are satellite irradiance retrievals. Herein we analyze the adequacy of the National Solar Radiation Database (NSRDB) to validate the WRF-Solar performance using high-quality global horizontal irradiance (GHI) observations across the CONUS. Based on the sufficient performance of NSRDB, we further analyze the WRF-Solar forecast errors across the CONUS, the growth of the forecasting errors as a function of the lead time, sensitivities to the grid spacing, and to the representation of the radiative effects of unresolved clouds. Our results based on WRF-Solar forecasts spanning the year of 2018 reveal a 7% median degradation of the mean absolute error (MAE) from the first to the second daytime period. Reducing the grid spacing from 9 km to 3 km leads to a 4% improvement in the MAE, whereas activating the radiative effects of unresolved clouds is desirable over most of the CONUS even at 3 km of grid spacing. A systematic overestimation of the GHI is found. These results illustrate the potential of GHI retrievals to contribute increasing the WRF-Solar performance.

scholarly journals Proposal to Refine Solar Radiation of Typical Meteorological Year Database and Evaluation on the Influence of Air-Conditioning Load

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 524
Author(s):  
Jihui Yuan ◽  
Kazuo Emura ◽  
Craig Farnham
Keyword(s):  
Solar Radiation ◽  
Air Conditioning ◽  
Energy Savings ◽  
Energy Resource ◽  
Global Solar Radiation ◽  
Resource Assessment ◽  
Weather Data ◽  
Diffuse Solar Radiation ◽  
Chinese Standard ◽  
The Impact

The Typical meteorological year (TMY) database is often used to calculate air-conditioning loads, and it directly affects the building energy savings design. Among four kinds of TMY databases in China—including Chinese Typical Year Weather (CTYW), International Weather for Energy Calculations (IWEC), Solar Wind Energy Resource Assessment (SWERA) and Chinese Standard Weather Data (CSWD)—only CSWD is measures solar radiation, and it is most used in China. However, the solar radiation of CSWD is a measured daily value, and its hourly value is separated by models. It is found that the cloud ratio (diffuse solar radiation divided by global solar radiation) of CSWD is not realistic in months of May, June and July while compared to the other sets of TMY databases. In order to obtain a more accurate cloud ratio of CSWD for air-conditioning load calculation, this study aims to propose a method of refining the cloud ratio of CSWD in Shanghai, China, using observed solar radiation and the Perez model which is a separation model of high accuracy. In addition, the impact of cloud ratio on air-conditioning load has also been discussed in this paper. It is shown that the cloud ratio can yield a significant impact on the air conditioning load.

The Correlations Between Acoustical Gravity Waves Caused by Solar Eclipse and the Solar Radiation

1992 ◽  
Vol 11 (2) ◽  
pp. 37-41 ◽  
Author(s):  
Jinlai Xie ◽  
Xunren Yang ◽  
Qitai Li
Keyword(s):  
Solar Radiation ◽  
Gravity Waves ◽  
Solar Eclipse ◽  
Ground Level ◽  
Atmospheric Moisture ◽  
Important Conclusion ◽  
Moisture Condition ◽  
Open Question ◽  
Annular Solar Eclipse ◽  
Abundant Data

Can solar eclipses generate AGWs? If so, how are they excited? This is still an open question and a long-standing dispute within academic circles. The annular solar eclipse which traversed the Chinese mainland on September 23rd 1987 afforded a rare and excellent opportunity to study this problem. Vast amounts of data of microbarometric pressure at ground level, radio-sondage, solar radiation and ionospheric probing were obtained from various observation stations. By making use of these abundant data synthetically, an important conclusion has been reached: there is an obvious accord between the period of the solar eclipse, AGW and the fluctuation period of solar direct radiation. All the solar eclipse AGWs in different places come from two different kinds of atmospheric oscillation, i.e., the forced oscillation generated directly by changes in direct solar radiation and the buoyancy oscillation in the local atmosphere above various spots. The former has a longer wave period and a larger amplitude, depending directly upon the radiation change during the solar eclipse; the latter has a shorter period and smaller amplitude, depending upon thermodynamic stability in the local atmosphere during the solar eclipse and the atmospheric moisture condition.

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