Diurnal Variation Of Solar Radiation Research Articles

Evaluation of Scikit-Learn Machine Learning Algorithms for Improving CMA-WSP v2.0 Solar Radiation Prediction

This article aims to evaluate the performance of solar radiation forecasts produced by CMA-WSP v2.0 (version 2 of the China Meteorological Administration Wind and Solar Energy Prediction System) and to explore the application of machine learning algorithms from the scikit-learn Python library to improve the solar radiation prediction made by the CMA-WSP v2.0. It is found that the performance of the solar radiation forecasting from the CMA-WSP v2.0 is closely related to the weather conditions, with notable diurnal fluctuations. The mean absolute percentage error (MAPE) produced by the CMA-WSP v2.0 is approximately 74% between 11:00 and 13:00. However, the MAPE ranges from 193% to 242% at 07:00–08:00 and 17:00–18:00, which is greater than that observed at other daytime periods. The MAPE is relatively low (high) for both sunny and cloudy (overcast and rainy) conditions, with a high probability of an absolute percentage error below 25% (above 100%). The forecasts tend to underestimate (overestimate) the observed solar radiation in sunny and cloudy (overcast and rainy) conditions. By applying machine learning models (such as linear regression, decision trees, K-nearest neighbors, random forests regression, adaptive boosting, and gradient boosting regression) to revise the solar radiation forecasts, the MAPE produced by the CMA-WSP v2.0 is significantly reduced. The reduction in the MAPE is closely connected to the weather conditions. The models of K-nearest neighbors, random forests regression, and decision trees can reduce the MAPE in all weather conditions. The K-nearest neighbor model exhibits the most optimal performance among these models, particularly in rainy conditions. The random forest regression model demonstrates the second-best performance compared to that of the K-nearest neighbor model. The gradient boosting regression model has been observed to reduce the MAPE of the CMA-WSP v2.0 in all weather conditions except rainy. In contrast, the adaptive boosting (linear regression) model exhibited a diminished capacity to improve the CMA-WSP v2.0 solar radiation prediction, with a slight reduction in MAPE observed only in sunny (sunny and cloudy) conditions. In addition, the input feature selection has a considerable influence on the performance of the machine learning model. The incorporation of the time series data associated with the diurnal variation of solar radiation as an input feature can further improve the model’s performance.

Boundary of nighttime ozone chemical equilibrium in the mesopause region: long-term evolution determined using 20-year satellite observations

Abstract. The assumption of nighttime ozone chemical equilibrium (NOCE) is widely employed for retrieving the Ox-HOx components in the mesopause from rocket and satellite measurements. In this work, the recently developed analytical criterion of determining the NOCE boundary is used (i) to study the connection of this boundary with O and H spatiotemporal variability based on 3D modeling of chemical transport and (ii) to retrieve and analyze the spatiotemporal evolution of the NOCE boundary in 2002–2021 from the SABER/TIMED dataset. It was revealed, first, that the NOCE boundary reproduces well the transition zone dividing deep and weak photochemical oscillations of O and H caused by the diurnal variations of solar radiation. Second, the NOCE boundary is sensitive to sporadic abrupt changes in the middle-atmosphere dynamics, in particular due to powerful sudden stratospheric warmings leading to the events of an elevated (up to ∼ 80 km) stratopause, which took place in January–March 2004, 2006, 2009, 2010, 2012, 2013, 2018, and 2019. Third, the space–time evolution of this characteristic expressed via pressure altitude contains a clear signal of an 11-year solar cycle in the 55∘ S–55∘ N range. In particular, the mean annual NOCE boundary averaged in this range of latitudes anticorrelates well with the F10.7 index with the coefficient of −0.95. Moreover, it shows a weak linear trend of 56.2±42.2 m per decade.

Differences in adaptation to light and temperature extremes of Chlorella sorokiniana strains isolated from a wastewater lagoon

Presently, two Chlorella sorokiniana strains sampled during summer (CS-S) and winter (CS-W) from a maturation pond and isolated by dominance were studied on their behavior on temperature and light extremes in batch experiments. Although both strains showed no differences in their tolerance of temperatures up to 45 °C, the growth rates, pigment contents and fatty acid compositions in response to PAR at 700 and 1,500 µmol m−2sec-1 differed. CS-W was less affected by photoinhibition and maintained constantly high growth rates. High radiation resulted in both strains in an equivalent decrease of chlorophyll a and accessory pigments indicating that the latter did not function as a light filter. PUFAS (18:3 and 16:3) increased in CS-W at high radiation by > 60% and decreased in CS-S by 8 %. Results indicate that CS-W is highly favorable for mass cultivation particularly in outdoors, in which diurnal variations of solar radiation occur.

Photovoltaic Direct Drive Water-saving irrigation System and Its Optimization Design Method

Photovoltaic irrigation has been widely used in many areas without conventional energy sources. In order to solve the problem of unstable operation and poor irrigation uniformity caused by the diurnal variation of solar radiation, a photovoltaic direct-drive water-saving irrigation system with automatic regulation was proposed. By using automatic control technology and the method of zonal rotation irrigation, all the electric energy generated by solar panels can be converted into irrigation energy under different light intensities, so that the water-saving irrigation equipment can work stably in different regions and the irrigation uniformity is ensured in different regions. According to the characteristics of solar energy resources and photovoltaic water-pumping units, the optimum design method of photovoltaic water-saving irrigation system is put forward. The minimum capacity of solar panels can meet the irrigation demand of a certain area, which can guide the engineering design of solar water-saving irrigation, greatly improve the engineering quality and energy utilization rate. It has the advantages of simple design, low cost, stable operation and energy-saving ring.

Sunlight Intensity, Photosynthetically Active Radiation Modelling and Its Application in Algae-Based Wastewater Treatment and Its Cost Estimation

In algal pond used for treating wastewater, a part of the solar radiation (PAR) is used by algae for photosynthesis, and rest of the solar energy is wasted. To date, no studies have been conducted that optimize these aspects (wasted solar radiation for heat production) from an operational cost perspective. Therefore, a model is developed for the estimation of photosynthetically active radiation (PAR) from solar radiation. Subsequently, derived PAR was utilized in the optimization algorithm. Experimental data on PAR and solar radiation were used to obtain empirical parameters of the developed model. Using empirical parameters, diurnal PAR was estimated for other locations for which the diurnal variation of solar radiation was not available. Afterwards, the estimated solar radiation was used to obtain the cost of algal biomass production using wastewater. For this purpose, a cost function was minimized. The cost function contains various cost components of algae-based wastewater treatment. The major costs of the treatment were incurred by the sunlight harvesting, and distribution equipment, whereas the major income was registered through the conversion of sunlight to heat and biomass production. The yearly cost of treating 1m3 wastewater in the proposed wastewater treatment plant could be varied from 186 to −44 (Rs, INR). The capital cost of constructing a proposed treatment plant having a capacity of 1000 m3/day varied from 11–45 crores INR.

Analytical Investigation of the Reaction‐Diffusion Waves in the Mesopause Photochemistry

AbstractThe mechanism of the generation of reaction‐diffusion waves in the mesopause region (80–90 km) has been studied analytically. These waves are the propagating phase fronts arising in the oscillations of O, O3, H, OH, and HO2 concentrations. They appear in the presence of horizontal eddy diffusion in zonal direction when mesospheric photochemistry responds subharmonically (with a period of 2 days) to diurnal variations of solar radiation. The photochemical system in the mesopause region is a nonlinear oscillator which can be roughly described by a system of two differential nonautonomous equations with power law nonlinearity which was derived in our earlier papers. To model the wave propagation, we have considered a continuous chain of oscillators with diffusion coupling and with the phase of external periodic forcing depending linearly on spatial coordinates. It was found that the reaction‐diffusion waves are caused by specific “wind” type transport appearing in the equations for the amplitudes of 2‐day photochemical oscillations of O and H concentrations due to the zonal inhomogeneity of the external forcing. The obtained expression for the wave propagation velocity fully confirmed the earlier numerical results that the magnitude of the velocity is proportional to the diffusion coefficient and the gradient of the external forcing phase. The wave propagation direction is determined by the definite phase relations specified by internal parameters of the system only.

KAITAN KETINGGIAN LAPISAN BATAS ATMOSFER DENGAN KONDISI CUACA BERDASARKAN PROFIL ANGIN VERTIKAL BERBASIS PENGAMATAN RADISONDE, RADAR CUACA DAN KELUARAN MODEL WRF-ARW

Lapisan Batas Atmosfer (LBA) merupakan bagian dari atmosfer paling bawah dimana medan aliran sangat dipengaruhi langsung oleh interaksi dengan permukaan bumi dan sensitif terhadap berbagai kondisi di permukaan bumi selama skala waktu singkat. Ketinggian LBA dapat bervariasi secara signifikan terhadap waktu akibat dari beberapa faktor termasuk dinamika skala luas, perawanan, percampuran konvektif dan variasi diurnal dari radiasi matahari. Di Indonesia, kajian mengenai LBA masih terbatas, sehingga kajian ini dilakukan untuk mengetahui hubungan antara ketinggian LBA dengan kondisi cuaca menggunakan metode profil vertikal angin dari data pengamatan (radar dan radiosonde) dan simulasi model numerik WRF-ARW. Hasilnya menunjukkan antara LBA dan kondisi cuaca hanya memiliki tingkat korelasi yang sedang dengan bias yang cukup besar dengan hasil pengamatan, namun simulasi keluaran model WRF-ARW dapat menggambarkan dengan cukup baik profil ketinggian LBA pada kondisi cuaca yang berbeda. Kondisi cuaca dapat mempengaruhi ketinggian LBA, dimana saat kondisi cuaca cerah, ketinggian LBA lebih tinggi jika dibandingkan dengan kondisi cuaca berawan atau hujan.

MATHEMATICAL MODEL OF SOLAR RADIATION INCIDENT ON AN ARBITRARILY ORIENTED SURFACE FOR ANY REGION IN RUSSIA

The paper deals with an original model of solar radiation incident on an arbitrarily oriented surface. This model has been designed to predict the main characteristics of solar radiation for any geographical point in Russia. The model is based on the isotropic model developed by Liu and Jordan and enables the researches to determine the values of solar radiation incident on an arbitrarily oriented surface at any given time period with the sampling interval of one second. The model implies the use of numerical values of the atmospheric transparency index and the surface albedo obtained from the NASA SSE (Surface meteorology and Solar Energy) database as initial data to ensure precise modeling of the incident solar radiation values including those for regions with no systematic actinometric observations. The paper presents the results of modeling the average daily values of solar radiation for ten Russian settlements located in the region between latitude of 43–62oN and longitude of 50–158oE. In order to verify the adequacy of the model, the results of instrumental terrestrial actinometric measurements are taken from meteorological stations included in the World Meteorological Organization network. The verification results show that the average relative model error for the considered meteorological stations does not exceed 11.7% for total solar radiation and 24.5% for scattered radiation. The authors developed the histograms of modeling errors in comparison with data from the World Radiation Data Center and NASA SSE. The analysis of the histograms revealed no systematic errors in the model since the errors were distributed uniformly and symmetrically with respect to the zero level. The paper compares the results of modeling the diurnal variation of solar radiation for 4 typical months of the year in Yekaterinburg with data from the World Radiation Data Center published in the periodic bulletin “Solar Radiation and Radiation Balance Data (The World Network)”. The developed model is implemented as a separate subsystem in MatLab/Simulink to enable its integration into the general model of the energy complex of an arbitrary configuration. The model can be used for studies concerned with the design, development and improvement of the energy systems including solar energy installations.

The mechanism of non-linear photochemical oscillations in the mesopause region

Abstract. The mechanism of generation of 2-day photochemical oscillations in the mesopause region (80–90 km) has been studied analytically. The initial system of equations of chemical kinetics describing the temporal evolution of O, O3, H, OH and HO2 concentrations with allowance for diurnal variations of solar radiation has been simplified successively to a system of two nonlinear first-order time equations with sinusoidal external forcing. The obtained system has a minimum number of terms needed for generation of 2-day oscillations. Linearization of this system near the period-doubling threshold permits separating explicitly a particular case of the Mathieu equation ẍ + α · sin ω t · x = 0, in which the first sub-harmonic (ω/2) of the exciting force starts to grow exponentially when the amplitude of external forcing (α) exceeds its threshold value. Finally, a system of two simplest differential equations with power-law nonlinearity has been derived that allows analytical investigation of the effect of arising of reaction-diffusion waves in the mesospheric photochemical system.

Theoretical investigation of the influence of a quasi‐2‐day wave on nonlinear photochemical oscillations in the mesopause region

The influence of a quasi‐2‐day atmospheric wave of given amplitude on the 2‐day photochemical oscillations occurring in the mesopause region (heights of 80 to 90 km) in the regime of subharmonic nonlinear response to diurnal variations of solar radiation is investigated. It is revealed that the most significant mechanism is periodic transport of minor gas constituents by the vertical wind associated with the wave. This mechanism may lead to phase locking of photochemical oscillations to wind oscillations and, thereby, to the formation of regular horizontal distribution of minor gas constituents with zonal wave number close to the wave number of the atmospheric wave. The influence on phase locking of two other factors, namely, transport by the zonal mean zonal wind and by the horizontal component of wind of the wave, is also analyzed.

Contrasts between the summertime surface energy balance and boundary layer structure at Dome C and Halley stations, Antarctica

The Antarctic research stations of Dome C and Halley lie at similar latitudes (∼75°S) and are thus subject to similar diurnal variation of solar radiation at the top of the atmosphere. However, the response of the atmospheric boundary layer to this diurnally varying forcing differs greatly at the two stations. At Dome C during summer there is a strong diurnal cycle in near‐surface temperature and wind speed, and a shallow (∼350 m) convective boundary layer is observed to grow in response to diurnal heating. At Halley, diurnal variations in temperature and wind speed are smaller than those at Dome C, and there is no clear diurnal variability in boundary layer depth. Analysis of the summertime surface energy budget for both stations indicates that the main reason for the different diurnal variability at the two stations is the greater partitioning of available energy into latent heat flux at the warmer Halley station. We argue that the diurnally varying convective boundary layer observed at Dome C will not be typical of the whole of the East Antarctic plateau.

Reactive-diffusion waves in the mesospheric photochemical system

The influence of horizontal eddy diffusion on photochemical oscillations of minor gas constituents in the mesopause region of the Earth’s atmosphere is investigated. It is shown that, when the spectrum of oscillations contains a pronounced second subharmonic (nonlinear response of the photochemical system to diurnal variations of solar radiation), reaction-diffusion waves in the form of travelling fronts and pulses of the phase of two-day oscillations may be excited in this region of the atmosphere.

Impact of a revised convective triggering mechanism on Community Atmosphere Model, Version 2, simulations: Results from short‐range weather forecasts

This study implements a revised convective triggering condition in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, Version 2 (CAM2), model to reduce its excessive warm season daytime precipitation over land. The new triggering mechanism introduces a simple dynamic constraint on the initiation of convection that emulates the collective effects of lower level moistening and upward motion of the large‐scale circulation. It requires a positive contribution from the large‐scale advection of temperature and moisture to the existing positive convective available potential energy (CAPE) for model convection to start. In contrast, the original convection triggering function in CAM2 assumes that convection is triggered whenever there is positive CAPE, which results in too frequent warm season convection over land arising from strong diurnal variation of solar radiation. We examine the impact of the new trigger on CAM2 simulations by running the climate model in numerical weather prediction (NWP) mode so that more available observations and high‐frequency NWP analysis data can be used to evaluate model performance. We show that the modified triggering mechanism has led to considerable improvements in the simulation of precipitation, temperature, moisture, clouds, radiations, surface temperature, and surface sensible and latent heat fluxes when compared to the data collected from the Atmospheric Radiation Measurement (ARM) Program at its Southern Great Plains (SGP) site. Similar improvements are also seen over other parts of the globe. In particular, the surface precipitation simulation has been significantly improved over both the continental United States and around the globe; the overestimation of high clouds in the equatorial tropics has been substantially reduced; and the temperature, moisture, and zonal wind are more realistically simulated. Results from this study also show that some systematic errors in the CAM2 climate simulations can be detected in the early stage of model integration. Examples are the extremely overestimated high clouds in the tropics in the vicinity of Intertropical Convergence Zone and the spurious precipitation maximum to the east of the Rockies. This has important implications in studies of these model errors since running the climate model in NWP mode allows us to perform a more in‐depth analysis during a short time period where more observations are available and different model errors from various processes have not compensated for the systematic errors.

Modeling of Ship Effluent Transport and Its Sensitivity to Boundary Layer Structure

The LES model is applied for studying ship track formation under various boundary layer conditions observed during the Monterey Area Ship Track experiment. Simulations in well-mixed and decoupled boundary layers show that ship effluents are easily advected into the cloud layer in the well-mixed convective boundary layer, whereas their transport may be suppressed by the subcloud transitional layer in the decoupled case. The clear difference between the well-mixed and decoupled cases suggests the important role of diurnal variation of solar radiation and consequent changes in the boundary layer stability for ship track formation. The authors hypothesize that, all other conditions equal, ship track formation may be facilitated during the morning and evening hours when the effects of solar heating are minimal. In a series of experiments, the authors also studied the effects of additional buoyancy caused by the heat from the ship engine exhaust, the strength of the subcloud transitional layer, and the subcloud layer saturation conditions. The authors conclude that additional heat from ship engine and the increase in ship plume buoyancy may indeed increase the amount of the ship effluent penetrating into the cloud layer. The result, however, depends on the strength of the stable subcloud transitional layer. Another factor in the ship effluent transport is the temperature of the subcloud layer. Its decrease will result in lowering the lifting condensation level and increased ship plume buoyancy. However, the more buoyant plumes in this case have to overcome a larger potential barrier. The relation between all these parameters may be behind the fact that ship tracks sometimes do, and sometimes do not, form in seemingly similar boundary layer conditions.

Diurnal variation of solar radiation on differently orientated surfaces of monuments

In the Northern Hemisphere and, in particular, at 6 different latitudes (38°, 42°, 45°, 48°, 50°, 56°) the flux of solar radiation which hits the vertical surfaces orientated in the eight main directions (North, North-East, East, South-East, South, South-West, West, North-West) has been computed and compared with the horizontal plane, at the time of the summer and winter solstices and equinoxes. This study has been carried out with the aim of furnishing a useful basis to calculate the quantity of energy which hits a surface, as an integral to find out when the maximum energy hits it, and to determine the time interval, during the day, during which a work of art is directly exposed to solar radiation. All this information is useful, in that solar radiation is an important forcing agent, and necessary in the biological and physico-chemical processes which lead to the degradation of a work of art. Furthermore, it is also useful for the management of the rooms or the environment around the monument, to know whether it is situated inside or outside. Therefore, the amount of energy reaching the various vertical surfaces has been compared to the amount of the energy received by the horizontal planes and which are normally acquired at the various monitoring stations. Moreover, the efficiency of the model depends on the correct choice of the atmospheric transmission coefficient α. Finally, some examples of the partial results obtained when such a model was applied to the Scrovegni Chapel, the Sistine Chapel, the Cathedral at Orvieto, the Horses of St. Mark in Venice and the Trajan Column, will be given.

A numerical research on the influences of the diurnal variation of solar radiation on the medium-range weather processes

In this paper, we use a spectral model for the medium-range numerical weather forecast to discuss the impact of the diurnal variation of solar radiation on the medium-range weather processes. Under the tests of two typical winter and summer cases, we find that the influences of the diurnal variation of solar radiation on summer weather are really important, especially on its rainfall, surface heat transport and 500 hPa height field. On winter weather, however, the influences are very weak.

A numerical simulation of diurnal variations of meteorological fields in summer

The influences of the Tibetan Plateau and the Rocky Mountains on diurnal variations of the meteorological fields in July are investigated by use of a five-layer global atmospheric general circulation model which includes various physical processes, including diurnal variation of solar radiation and real topography. In this paper, a brief description of the model is given first and then we emphatically discuss the results by comparatively analysing the influences of the Tibetan Plateau and the Rocky Mountains on diurnal changes of temperature, the geopotential height, the horizontal and the vertical flows, as well as the vertical circulations in summer. The comparative analyses show that there are very prominent diurnal variations of temperature, geopotential height, wind fields and vertical circulations in the mountainous regions, the amplitudes of their variations are proportional to the scales of topography.

Numerical Simulation of the Development of Mean Monsoon Circulation in July

Eight different experiments are carried out, ranging from 8 to 20 days, with a primitive equation model consisting of five atmospheric layers and one oceanic layer. The purpose is to investigate the relative importance of radiative heating and deep cumulus condensation, orography, and initial conditions for the development of the mean monsoon circulation from June to July in the 0-180 deg E, 25 deg S - 55 deg N region. Two alternative initial states are used, one based on the observed monthly mean June pressure distribution, the other on the mean June zonal average pressure distribution. Whereas large-scale condensation and actual land and sea distributions are included in every experiment, deep cumulus cone condensation and radiative heating are always taken together. It is found that the means sea level pressure distribution and low-level flow pattern produced by these simulations are in the main determined by the diabatic heating distribution and are influenced somewhat by orography; they are, however, almost independent of the initial state. The low pressure systems are found to develop faster when diurnal variation of solar radiation is allowed for; this is thought to be due mainly to the more vigorous cumulus activity during the day.

Radiation at the Outer Surface of Pot and Heat Exchange in Pot Soil

The purposes of this paper are to elucidate the distributions of solar radiation and net radiation at the outer surface of a pot, and to determine the quantity of flowed heat in the pot soil in both horizontal and vertical directions.Three different conditions of the surface were prepared using Wagner pot (1/2000a). The outer surfaces of pots were coated with black lacquer, covered with aluminum film, and not covered respectively.Observations were made on August 5 and December 16 in 1978.1) On August 5, the daily amounts of solar radiation calculated directly were the greatest at the east and west side surfaces which were 54% as much as that at the horizontal surface, while those at the south (23%) and north side surfaces (7%) were smaller than those at other surfaces. Its distribution pattern showed a cardioid. On December 16, radiations at the surface of all directions became greater than that of the horizontal surface owing to a low altitude of the sun, especially radiation at the south side surface was 168% as much as that at the horizontal surface.2) Measured solar radiations at sunrise and at sunset differed from those of calculated direct solar radiations. The diurnal variations of solar radiation at all surfaces of pot showed a kind of sine curve. On August 5, the daily amounts of solar radiation at the south and north side surfaces showed 36% and 19% as much as that at the horizontal surface, respectively, while on the west and east side surfaces they were about 40%. These differences among the directions were less than those of calculated direct solar radiation. On December 16, radiations received in most directions at the outer surface of pot were greater than that at the horizontal surface.3) Net radiations at the south side and near middle part on the soil surface of pot had maxima at noon, at the west side surface at 14:00, and at the east side surface at 10:00 on December 16.The diurnal variation of net radiation was small at the north side surface. Radiation at the south side surface of pot coated with black lacquer was the greatest and followed by those at the west and east side surfaces. Net radiation at the south side surface of pot coated with black lacquer was 165% as much as that at a plain pot. The radiation of pot covered with aluminum film was the smallest and half as much as that of pot coated with black lacquer.4) In the diurnal range of flowed heat in the pot soil, there were little differences among all horizontal directions, but in the vertical directions it was the greatest at the south side surface and this tendency was more remarkable on December 16 than on August 5.

Formation and Persistence of Summertime Arctic Stratus Clouds

Abstract We have developed a numerical model which can explain the principle observed properties of the summertime stratus clouds occurring over the Arctic Basin. Warm, moist air from the surrounding land masses is modified as it passes over the melting pack ice. Motions are calculated on the basis of a fixed pressure field, but all other relevant fields (temperature, mixing, solar and terrestrial radiation, water in the liquid and vapor phase) are calculated on the basis of an internally consistent thermodynamic model which is considered to be complete in all essential physical processes. The ubiquitous occurrence of stratus clouds is explained in terms of the relative unimportance of cloud dissipative processes over the Arctic Ocean. The commonly observed layering results from the trapping of solar radiation inside a cloud which is opaque to thermal radiation. The absence of similar layering in mid-latitude stratus is probably due to the diurnal variation of solar radiation, which is largely absent in t...