Journal articles: 'Solar daily variation'

1

Kouris, S. S., P. A. Bradley, and P. Dominici. "Solar-cycle variation of the daily." Annales Geophysicae 16, no. 8 (1998): 1039. http://dx.doi.org/10.1007/s005850050673.

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2

De Meyer, F. "Modulation of the solar daily geomagnetic variation." Journal of Atmospheric and Terrestrial Physics 48, no. 2 (February 1986): 115–30. http://dx.doi.org/10.1016/0021-9169(86)90076-0.

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3

Rahim, Zain, and Abdul Salam Kumbher. "Solar daily variation at geomagnetic observatories in Pakistan." Journal of Atmospheric and Solar-Terrestrial Physics 140 (March 2016): 41–54. http://dx.doi.org/10.1016/j.jastp.2016.01.016.

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Shinbori, Atsuki, Yukinobu Koyama, Masahito Nosé, Tomoaki Hori, and Yuichi Otsuka. "Characteristics of Seasonal Variation and Solar Activity Dependence of the Geomagnetic Solar Quiet Daily Variation." Journal of Geophysical Research: Space Physics 122, no. 10 (October 2017): 10,796–10,810. http://dx.doi.org/10.1002/2017ja024342.

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5

Dewitte, Steven, Jan Cornelis, and Mustapha Meftah. "Centennial Total Solar Irradiance Variation." Remote Sensing 14, no. 5 (February 22, 2022): 1072. http://dx.doi.org/10.3390/rs14051072.

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Total Solar Irradiance (TSI) quantifies the solar energy received by the Earth and therefore is of direct relevance for a possible solar influence on climate change on Earth. We analyse the TSI space measurements from 1991 to 2021, and we derive a regression model that reproduces the measured daily TSI variations with a Root Mean Square Error (RMSE) of 0.17 W/m2. The daily TSI regression model uses the MgII core to wing ratio as a facular brightening proxy and the Photometric Sunspot Index (PSI) as a measure of sunspot darkening. We reconstruct the annual mean TSI backwards to 1700 based on the Sunspot Number (SN), calibrated on the space measurements with an RMSE of 0.086 W/m2. The analysis of the 11 year running mean TSI reconstruction confirms the existence of a 105 year Gleissberg cycle. The TSI level of the current grand minimum is only about 0.15 W/m2 higher than the TSI level of the grand minimum in the beginning of the 18th century.

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6

Makarov, Georgy. "GEOMETRIC FACTOR IN SEASONAL VARIATIONS OF DAILY AVERAGE VALUES OF THE GEOMAGNETIC INDEX Dst." Solar-Terrestrial Physics 6, no. 4 (December 22, 2020): 50–56. http://dx.doi.org/10.12737/stp-64202008.

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The work uses data on the geomagnetic index Dst for the period 1966–2015. Under quiet conditions, the occurrence of seasonal variations of the daily average Dst index depends on geometric factors of the interaction between the solar wind and the magnetosphere; and under disturbed conditions, on the development of a partial ring current in the magnetosphere. At large negative values of the Dst index, there is no seasonal variation in it. The imperfection of the network of Dst stations is assumed to lead to the formation of annual variation in Dst. The formation of a semiannual variation is associated with the movement of the plasma sheet relative to the plane of the geomagnetic equator during the annual rotation of Earth around the Sun. Based on the data on semiannual variations in the number of days n(Dst), the critical daily average value of the geomagnetic index Dst is determined, starting from which we can speak of disturbed days: Dst≤–24 nT.

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7

Medvigy, David, and Claudie Beaulieu. "Trends in Daily Solar Radiation and Precipitation Coefficients of Variation since 1984." Journal of Climate 25, no. 4 (February 8, 2012): 1330–39. http://dx.doi.org/10.1175/2011jcli4115.1.

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Abstract This study investigates the possibility of changes in daily scale solar radiation and precipitation variability. Coefficients of variation (CVs) were computed for the daily downward surface solar radiation product from the International Satellite Cloud Climatology Project and the daily precipitation product from the Global Precipitation Climatology Project. Regression analysis was used to identify trends in CVs. Statistically significant changes in solar radiation variability were found for 35% of the globe, and particularly large increases were found for tropical Africa and the Maritime Continent. These increases in solar radiation variability were correlated with increases in precipitation variability and increases in deep convective cloud amount. The changes in high-frequency climate variability identified here have consequences for any process depending nonlinearly on climate, including solar energy production and terrestrial ecosystem photosynthesis. To assess these consequences, additional work is needed to understand how high-frequency climate variability will change in the coming decades.

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8

Choe, Won Chol. "Relation of Magnetic Fields with Solar Activity Indexes in a Descending Phase of Solar Cycle." International Astronomical Union Colloquium 141 (1993): 394–96. http://dx.doi.org/10.1017/s0252921100029481.

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AbstractWe examine the solar activity indexes (relative intensity of sunspots and faculae) of an active region #83137 during 1983 June 21–26. The results are compared with daily variation of magnetic fields of the region to find a characteristic of solar activity variation in the descending phase of solar cycle.

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9

Katongole, Daniel N., Karidewa Nyeinga, Denis Okello, Daniel Mukiibi, James Mubiru, and Yeeko Kisira. "Spatial and Temporal Solar Potential Variation Analysis in Uganda Using Measured Data." Tanzania Journal of Science 49, no. 1 (March 31, 2023): 1–14. http://dx.doi.org/10.4314/tjs.v49i1.1.

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The paper presents an analysis of spatial and temporal solar potential variations in Uganda. The solar radiation potential distribution was investigated based on measured data from 56 ground meteorological stations across Uganda from January 2015 to February 2022. The data were recorded after every 5-minute interval. The monthly average daily Global Horizontal Irradiance (GHI) was analysed using the spatial inverse distance weighting (IDW) interpolation technique in ArcGIS 10.7.1. The GHI distribution was found to have maxima at equinox and minimum between June and July. The average global horizontal irradiation is found to be 1680 KWh per year, with a daily variability below 10%. This is above the threshold for solar energy applications and with such low variability, large scale solar PV plants can be installed with minimum backup requirements. Northern Uganda receives the highest average daily global horizontal irradiation of 5.38 Whm–2 day–1, while Western Uganda receives 4.16 Whm–2 day–1, the lowest. The average AM/PM ratio depicted a value above 2 for all regions in Uganda and therefore, optimal solar energy exploitation for fixed systems favours eastern orientation. The central, eastern and northern Uganda which is 69.3% of the country has relief favourable for large scale solar PV power plants and CSP facilities. Keywords: GHI, IDW, Global solar radiation, Solar insolation, PV power plants, Uganda

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10

Akpabio, Louis, Akpan Udoimuk, and Sunday Etuk. "Preliminary studies on global solar radiation in Mbalmayo, Cameroon." Thermal Science 13, no. 4 (2009): 207–11. http://dx.doi.org/10.2298/tsci0904207a.

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This paper presents preliminary studies on the global solar radiation in a horizontal surface along with the prevailing meteorological conditions measured during the period 1999-2001 in Mbalmayo, Cameroon. Hourly, daily, and mean monthly values of global solar radiation and meteorological data were obtained from the International Institute of Tropical Agriculture automatic weather station of Mbalmayo. The data were processed as daily, hourly, sum of 10-day data for 8.00/12.00/16.00/20.00 hours, decadal hourly, decadal daily, and mean monthly data. The highest measured daily, decadal hourly, decadal daily, and mean monthly data for global solar radiation in Mbalmayo was found to be 29.7, 2.76, 21.8, and 20.1 MJm2, respectively. The highest hourly global solar radiation value up to 182.44 MJm2 was observed between March 21-31, 1999. Apart from the global solar radiation measurements, the main observed meteorological parameters were, soil temperature, temperature, wind speed, precipitation, and relative humidity. The results show that there exist seasonal tendencies in the variation of global solar radiation. The range of variation of these radiations and the distribution puts Mbalmayo has a high potential for solar energy utilization.

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11

Tatsuoka, R., and K. Nagashima. "Formulation of cosmic-ray solar daily variation and its seasonal variation, produced from generalized stationary anisotropy of solar origin." Il Nuovo Cimento C 8, no. 3 (May 1985): 320–28. http://dx.doi.org/10.1007/bf02574716.

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12

SALEM, A. I., M. GABR, S. SALEEM, and A. H. BASSYOUNI. "Analysis of solar radiation measurements at EI-Kharga (250 N, 300E), Egypt." MAUSAM 44, no. 1 (December 31, 2021): 39–44. http://dx.doi.org/10.54302/mausam.v44i1.3772.

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Daily global solar. radiation data of EI-Kharga for five year (1984-88) have been processed, analysed and classified into eight radiation levels spaced at an interval of 4.19 MJ m-2 day-l. Mean annual monthly and daily total the diurnal variation, and the frequency distribution of daily totals of global solar radiation are computed and discussed. A correlation between the hourly values of the clearness and diffuse indices were obtained and the recommended correlation ,equations were also given. The, results presented in this analysis are encouraging since they Indicate that periods of several days of low radiation of less than 8.38 MJm , day are rare. This In turn means that the weather sequence variations are not expected, to be of great Importance when considering the storage problems Involved In solar process design.

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13

Jeong, Jaesik, and Suyeon Oh. "Seasonal Variation of Cosmic Ray Intensity Observed by the Oulu Neutron Monitor." Journal of Astronomy and Space Sciences 37, no. 3 (September 2020): 165–70. http://dx.doi.org/10.5140/jass.2020.37.3.165.

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Muons and neutrons are representative secondary particles that are generated by interactions between primary cosmic ray particles (mostly protons) and the nuclei of atmospheric gas compounds. Previous studies reported that muons experience seasonal variations because of the meteorological effects of temperature. The intensity of neutrons has a typical modulation with various periods and reasons, such as diurnal and solar variation or transient events. This paper reports that cosmic ray particles, which were observed by neutron monitors, have seasonal variations using the daily data at the Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily data were normalized by two different transformations: transformations with respect to the grand mean and yearly mean. The data after transformation with respect to the yearly mean showed more statistical stability and clear seasonal variations. On the other hand, it is difficult to determine if the seasonal variation results from terrestrial effects, such as meteorological factors, or extraterrestrial effects, such as the position of the Earth in its orbit of revolution.

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14

Schlapp, D. M., R. Sellek, and E. C. Butcher. "Studies of worldwide secular trends in the solar daily geomagnetic variation." Geophysical Journal International 100, no. 3 (March 1990): 469–75. http://dx.doi.org/10.1111/j.1365-246x.1990.tb00699.x.

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15

Çelik, Cengiz. "The solar daily geomagnetic variation and its dependence on sunspot number." Journal of Atmospheric and Solar-Terrestrial Physics 104 (November 2013): 75–86. http://dx.doi.org/10.1016/j.jastp.2013.08.014.

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16

Souahlia, Abdelkerim, Abdelhalim Rabehi, and Abdelazize Rabehi. "Hybrid Models for Daily Global Solar Radiation Assessment." Journal of Engineering and Exact Sciences 9, no. 4 (June 6, 2023): 15926–01. http://dx.doi.org/10.18540/jcecvl9iss4pp15926-01e.

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Daily solar radiation forecasting has recently become critical in developing solar energy and its integration into grid systems. Despite the huge number of proposed forecasting techniques, an accurate estimation remains a significant challenge because of the non-stationary variation of solar radiation components due to the continuously changing climatic conditions. Usually, several input data predictors are used for the forecasting process, which can cause redundancy and correlation between data features. This work assesses a set of feature selection techniques to check their ability to select the relevant predictors and reduce redundant and irrelevant information. An Artificial Neural Network is used to fit the measured solar radiation based on the selected features. The developed model is evaluated through various objective evaluation metrics using historical data of three years measured at the Ghardaiaregion inAlgeria. Results show the effectiveness of the proposed method, where values of 0,0189, 0.0286, 5.4387, and 98.28% have been found as MABE, RMSE, nRMSE and r, respectively.

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17

Makarov, Georgy. "GEOMETRIC FACTOR IN SEASONAL VARIATIONS OF DAILY AVERAGE VALUES OF THE GEOMAGNETIC INDEX Dst." Solnechno-Zemnaya Fizika 6, no. 4 (December 22, 2020): 59–66. http://dx.doi.org/10.12737/szf-64202008.

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The work uses data on the geomagnetic index Dst for the period 1966–2015. Under quiet conditions, the occurrence of seasonal variations of the daily average Dst index depends on geometric factors of the interaction between the solar wind and the magnetosphere; and under disturbed conditions, on the development of a partial ring current in the magnetosphere. At large negative values of the Dst index, there is no seasonal variation in it. The imperfection of the network of Dst stations is assumed to lead to the formation of annual variation in Dst. The formation of a semiannual variation is associated with the movement of the plasma sheet relative to the plane of the geomagnetic equator during the annual rotation of Earth around the Sun. Based on the data on semiannual variations in the number of days n(Dst), the critical daily average value of the geomagnetic index Dst is determined, starting from which we can speak of disturbed days: Dst≤–24 nT.

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18

Wang, Jian Ping, Bo Chen, Jin Zheng, and Peng Yun Li. "Analysis on the Daily Temperature Variation of a Concrete Slab under Environmental Effects." Advanced Materials Research 671-674 (March 2013): 2530–34. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.2530.

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The dynamic temperature field of a concrete slab is actively studied in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab with the aid of the commercial software package ANSYS. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature at different time. The made observations demonstrate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other concrete structures as well.

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19

Immel, Thomas J., Richard W. Eastes, William E. McClintock, Steven B. Mende, Harald U. Frey, Colin Triplett, and Scott L. England. "Daily Variability in the Terrestrial UV Airglow." Atmosphere 11, no. 10 (September 30, 2020): 1046. http://dx.doi.org/10.3390/atmos11101046.

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New capability for observing conditions in the upper atmosphere comes with the implementation of global ultraviolet (UV) imaging from geosynchronous orbit. Observed by the NASA GOLD mission, the emissions of atomic oxygen (OI) and molecular nitrogen (N2) in the 133–168-nm range can be used to characterize the behavior of these major constituents of the thermosphere. Observations in the ultraviolet from the first 200 days of 2019 indicate that the oxygen emission at 135.6 nm varies much differently than the broader Lyman-Birge-Hopfield (LBH) emission of N2. This is determined from monitoring the average instrument response from two roughly 1000 km2 areas, well separated from one another, at the same time of each day. Variations in the GOLD response to UV emissions in the monitored regions are determined, both in absolute terms and relative to a running 7-day average of GOLD measurements. We find that variations in N2 emissions in the two separate regions are significantly correlated, while oxygen emissions, observed in the same fixed geographic regions at the same universal time each day, exhibit a much lower correlation, and exhibit no correlation with the N2 emissions in the same regions. This indicates that oxygen densities in the airglow-originating altitude range of 150–200 km vary independently from the variations in nitrogen, which are so well correlated across the dayside to suggest a direct connection to variation in solar extreme-UV flux. The relation of the atomic oxygen variations to solar and geomagnetic activity is also shown to be low, suggesting the existence of a regional source that modifies the production of atomic oxygen in the thermosphere.

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20

Cutler, Paul M., and D. Scott Munro. "Visible and near-infrared reflectivity during the ablation period on Peyto Glacier, Alberta, Canada." Journal of Glaciology 42, no. 141 (1996): 333–40. http://dx.doi.org/10.1017/s0022143000004184.

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AbstractModels for calculating glacier mass balance are sensitive to surface reflectivity variation. Fieldwork carried out on Peyto Glacier, Alberta, Canada, contributes to the data set available for ice-reflectivity parameterization in such models. Hemispherical reflectivity in the visible and near-infrared parts of the solar spectrum was obtained for rock, snow and three contrasting glacier surfaces to examine temporal and spatial variations. Glacier-ice near-infrared reflectivity displays only minor spatial variation (0.12–0.17) in comparison with the visible range (0.23–0.40), the latter being influenced primarily by surface impurity content. Surface roughness is of minor importance compared with impurities. Temporal variation of reflectivity was weak at all glacier-ice and rock locations; slight variations observed were due to changes in either solar zenith angle or cloud amount. Snow reflectivity displayed pronounced diurnal asymmetry and a larger response to cloud cover. The minimal temporal variation in glacier-ice reflectivity simplifies its parameterization. This behaviour is additionally useful for satellite-based measurements of the reflectivity field on larger glaciers, as images obtained within a 6 h window centred on solar noon are likely to yield values which are within 2–3% of daily mean values.

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Cutler, Paul M., and D. Scott Munro. "Visible and near-infrared reflectivity during the ablation period on Peyto Glacier, Alberta, Canada." Journal of Glaciology 42, no. 141 (1996): 333–40. http://dx.doi.org/10.3189/s0022143000004184.

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AbstractModels for calculating glacier mass balance are sensitive to surface reflectivity variation. Fieldwork carried out on Peyto Glacier, Alberta, Canada, contributes to the data set available for ice-reflectivity parameterization in such models. Hemispherical reflectivity in the visible and near-infrared parts of the solar spectrum was obtained for rock, snow and three contrasting glacier surfaces to examine temporal and spatial variations. Glacier-ice near-infrared reflectivity displays only minor spatial variation (0.12–0.17) in comparison with the visible range (0.23–0.40), the latter being influenced primarily by surface impurity content. Surface roughness is of minor importance compared with impurities. Temporal variation of reflectivity was weak at all glacier-ice and rock locations; slight variations observed were due to changes in either solar zenith angle or cloud amount. Snow reflectivity displayed pronounced diurnal asymmetry and a larger response to cloud cover. The minimal temporal variation in glacier-ice reflectivity simplifies its parameterization. This behaviour is additionally useful for satellite-based measurements of the reflectivity field on larger glaciers, as images obtained within a 6 h window centred on solar noon are likely to yield values which are within 2–3% of daily mean values.

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22

Kirkwood, S., M. Hervig, E. Belova, and A. Osepian. "Quantitative relation between PMSE and ice mass density." Annales Geophysicae 28, no. 6 (June 23, 2010): 1333–43. http://dx.doi.org/10.5194/angeo-28-1333-2010.

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Abstract. Radar reflectivities associated with Polar Mesosphere Summer Echoes (PMSE) are compared with measurements of ice mass density in the mesopause region. The 54.5 MHz radar Moveable Atmospheric Radar for Antarctica (MARA), located at the Wasa/Aboa station in Antarctica (73° S, 13° W) provided PMSE measurements in December 2007 and January 2008. Ice mass density was measured by the Solar Occultation for Ice Experiment (SOFIE). The radar operated continuously during this period but only measurements close to local midnight are used for comparison, to coincide with the local time of the measurements of ice mass density. The radar location is at high geographic latitude but low geomagnetic latitude (61°) and the measurements were made during a period of very low solar activity. As a result, background electron densities can be modelled based on solar illumination alone. We find a close correlation between the time and height variations of radar reflectivity and ice mass density, at all PMSE heights, from 80 km up to 95 km. A quantitative expression relating radar reflectivities to ice mass density is found, including an empirical dependence on background electron density. Using this relation, we can use PMSE reflectivities as a proxy for ice mass density, and estimate the daily variation of ice mass density from the daily variation of PMSE reflectivities. According to this proxy, ice mass density is maximum around 05:00–07:00 LT, with lower values around local noon, in the afternoon and in the evening. This is consistent with the small number of previously published measurements and model predictions of the daily variation of noctilucent (mesospheric) clouds and in contrast to the daily variation of PMSE, which has a broad daytime maximum, extending from 05:00 LT to 15:00 LT, and an evening-midnight minimum.

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23

Flo, Ana, Ana C. Calpena, Antoni Díez-Noguera, Alfons del Pozo, and Trinitat Cambras. "Daily Variation of UV-induced Erythema and the Action of Solar Filters." Photochemistry and Photobiology 93, no. 2 (January 5, 2017): 632–35. http://dx.doi.org/10.1111/php.12670.

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24

Shinoda, Toshiaki. "Impact of the Diurnal Cycle of Solar Radiation on Intraseasonal SST Variability in the Western Equatorial Pacific." Journal of Climate 18, no. 14 (July 15, 2005): 2628–36. http://dx.doi.org/10.1175/jcli3432.1.

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Abstract The mechanism by which the diurnal cycle of solar radiation modulates intraseasonal SST variability in the western Pacific warm pool is investigated using a one-dimensional mixed layer model. SSTs in the model experiments forced with hourly surface fluxes during the calm–sunny phase of intraseasonal oscillation are significantly warmer than those with daily mean surface fluxes. The difference in two experiments is explained by upper-ocean mixing processes during nighttime. Surface warming during daytime creates a shallow diurnal warm layer near the surface (0–3 m), which can be easily eroded by surface cooling during nighttime. Further cooling, however, requires a substantial amount of energy because deeper waters need to be entrained into the mixed layer. Since the shallow diurnal layer is not formed in the experiment with daily mean surface fluxes, the SST for the hourly forcing case is warmer most of the time due to the diurnally varying solar radiation. Sensitivity of the intraseasonal SST variation to the penetrative component of solar radiation is examined, showing that the diurnal cycle plays an important role in the sensitivity. Solar radiation absorbed in the upper few meters significantly influences intraseasonal SST variations through changes in amplitude of diurnal SST variation.

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25

Tlatova, Kseniya A., Valeriya Vasil’eva, and Andrey Tlatov. "Reconstruction of the Filament Properties, Based on Centenarian Daily Observations of the Sun in Hα Line." Proceedings of the International Astronomical Union 13, S335 (July 2017): 187–90. http://dx.doi.org/10.1017/s1743921317008195.

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AbstractPreliminary results of distinguishing solar filaments on daily observation data at the Hα spectral line of the Kodaikanal Solar Observatory (1912-2002) are presented.To distinguish the boundaries of solar filaments, methods have been developed, based on automatic procedures for distinguishing low-contrast objects on the solar disk as well as on editing the boundaries of selected structures in semi-automatic mode. An analysis of solar filaments’ characteristics has been performed. We are considered variation of the average tilt-angle and the radius of curvature of the filaments in 15-23 cycles of activity.

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Jiménez, A., P. L. Pallé, J. C. Pérez, C. Régulo, T. Roca Cortés, G. R. Isaak, C. P. McLeod, and H. B. van der Raay. "The solar oscillations spectrum and the solar cycle." Symposium - International Astronomical Union 123 (1988): 205–9. http://dx.doi.org/10.1017/s0074180900158085.

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During the summer seasons of the years 1977 to 1985 daily velocity measurements of solar global oscillations have been obtained using a resonant scattering spectrometer. After calculating the power spectra of the daily residuals, the mean for each season is found. Several discrete frequency intervals are defined in the spectrum which yield information on the characteristics of the oscillations and noise levels. The mean power in these intervals and the cut-off frequency of the p-mode spectrum, determined for each year, are correlated with the solar activity cycle. Furthermore, several series of 13 contiguous days for each year are analyzed. The frequency and amplitude of the p modes of 1 ≤ 3 and 11 ≤ n ≤ 33 are determined and their average for these years is found. The frequency differences between modes of the same degree 1 and between neighbouring modes are found. Their variation over the years is compared with the solar activity cycle.

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Yusoff, Mohd Irwan, Muhamad Irwanto, Safwati Ibrahim, Gomesh Nair, Syed Idris Syed Hassan, and Muhamad Fitra. "Estimating Daily Solar Radiation Using Hargreaves Model in Eastern Malaysia." Applied Mechanics and Materials 699 (November 2014): 564–69. http://dx.doi.org/10.4028/www.scientific.net/amm.699.564.

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This paper presents the forecasting of solar radiation in Kelantan, Eastern Malaysia for the year of 2011 using Hargreaves model. This estimation is based on latitude and daily minimum and maximum temperature in Kelantan. The measured and estimated solar radiation data were compared for the year 2011 and analyzed using coefficient of residual mass (CRM), root mean squared error (RMSE), coefficient of determination (R2) and percentage error (e). The results showed that the value ofCRMis 0.09, it indicates the tendency of the estimation model to under-estimate the measure solar radiation. Meanwhile, the value ofRMSEis 8.21% and the value ofR2is 0.8661, closed to 1 indicates that about 86.61% of the total variation is explained in the data. For thee, the value is 7.98%, it indicates that the model estimation is good.

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DAS, H. P., and A. D. PUJARI. "A simple approach towards estimating solar irradiance." MAUSAM 44, no. 3 (January 1, 2022): 239–42. http://dx.doi.org/10.54302/mausam.v44i3.3839.

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Solar radiation is or vital interest in characterizing an area with respect to its agricultural potential. However, these are not readily available for a large network. An attempt. has been made to deduce solar irradiance from climatic data, such as temperature range. Based on daily data of Pune for 1986-90, a relationship has been developed between atmospheric transmittance and the daily range of air temperature. The model developed has been tested on independent data and found to give fairly accurate estimation of solar irradiance. Nearly 70% of the variation in daily solar radiation could be explained by this simple method. The effect of solar irradiance on microclimate has also been discussed. The model developed has been tested for Hyderabad and Calcutta and found to give encouraging results.

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De Michelis, P., R. Tozzi, and G. Consolini. "Principal components' features of mid-latitude geomagnetic daily variation." Annales Geophysicae 28, no. 12 (December 21, 2010): 2213–26. http://dx.doi.org/10.5194/angeo-28-2213-2010.

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Abstract. The ionospheric and magnetospheric current systems are responsible of the daily magnetic field changes. Recently, the Natural Orthogonal Components (NOC) technique has been applied to model the physical system responsible of the daily variation of the geomagnetic field, efficiently and accurately (Xu and Kamide, 2004). Indeed, this approach guarantees that the number of parameters used to represent the physical process is small as much as possible, and consequently process control for such system becomes apparent. We focus our present study on the analysis of the hourly means of the magnetic elements H, D and Z recorded at L'Aquila observatory in Italy from 1993 to 2004. We apply to this dataset the NOC technique to reconstruct the 3-dimensional structures of the different ionospheric and magnetospheric current systems which contribute to the geomagnetic daily variations. To support our interpretation in terms of the different ionospheric and magnetospheric current systems, the spectral and statistical features of the time-dependent amplitudes associated to the set of natural orthogonal components are analyzed and compared to those of a set of descriptors of the magnetospheric dynamics and solar wind changes.

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Upadhaya, Poojan, Hongbo Du, and Raghava R. Kommalapati. "Meteorological Detrending of Ozone at Three Sites in the Dallas-Fort Worth Area: Application of KZ Filter Method." Atmosphere 11, no. 11 (November 13, 2020): 1226. http://dx.doi.org/10.3390/atmos11111226.

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The Dallas-Fort Worth (DFW) area that experiences high temperature and intense solar radiation falls into the moderate nonattainment classification. The variation in meteorological parameters plays an important role in ambient ozone levels variation. Meteorological influences need to be decoupled from ozone data for long-term trend analysis. Temporal separation of maximum daily average 8-h ozone (MDA8 ozone), maximum daily temperature (TMAX), daily average solar radiation (DASR), and daily average wind speed (DAWS) were conducted using Kolmogorov-Zurbenko (KZ) filter for ozone records at Keller (C17), Arlington (C61), Red Bird (C402) monitoring stations in the DFW area from 2003 to 2017. Temporal separation, regression analysis, and meteorological detrending were performed. The long-term component had a clear and stable trend. The contribution of the long-term component to total variation was negligible, which is less than 2%. This is due to the removal of the data noise from the original time series data. The seasonal component had a major contribution (55% to 72%) in the total variation of the maximum temperature and solar radiation. However, the short-term component was dominant in the total variation of the MDA8 ozone (41–54%) and wind speed (68–79%). Regression analysis showed the baseline component bears the highest correlation than the short-term and raw. Solar radiation had the highest correlation to the MDA8 ozone, followed by temperature data in all three stations. Meteorological detrending showed the detrended long-term ozone had an increasing trend. The increasing trend was significant at C402 with a trend of 0.19 ± 0.006 ppb/y (0.398 R2), whereas slight increasing trends were found at C17 (0.072 ± 0.006 (0.107 R2)) and at C61 (0.019 ± 0.007 (0.005 R2)). The increasing trend of long-term components of MDA8 ozone was justified by the increasing level of NOx and VOCs from the mobile sources in the DFW area.

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KC, Bed Raj, and Shekhar Gurung. "Study of Solar Energy Potential using CMP6 Pyranometer at Nepalgunj, Nepal." Journal of Advanced Academic Research 3, no. 1 (February 11, 2017): 51–58. http://dx.doi.org/10.3126/jaar.v3i1.16617.

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The global solar radiation (GSR) is measured at the horizontal surface since 2011 using calibrated CMP6 Pyranometer at Nepalgunj which is located at an altitude 150m above sea level. This paper explains the daily, monthly and seasonal variation of global solar radiation and also compares temperature with global solar radiation. The average temperature in Nepalgunj varies between 44°C (it is hottest from May through July) and 30°C, although during winter (November-January) it can reach 4°C. The annual average daily global solar radiation is about 12.9MJ/m2/day which is sufficient to promote active and passive solar energy technology in Nepalgunj and other similar geographical locations.

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TRIVEDI, NB, and RG RASTOGI. "Lunar tidal oscillations in horizontal magnetic intensity at Kodaikanal during periods of low and high sunspots." MAUSAM 20, no. 3 (April 30, 2022): 235–46. http://dx.doi.org/10.54302/mausam.v20i3.5452.

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The paper describes the lunar daily (L) variations at fixed lunar ages and the lunar monthly (M) variations at fixed solar hours in horizontal magnetic intensity (.H) at Kodaikanal for the low sunspot period, Jan, 1951 to Dec, 1955; and for the high sunspot period Jan. 1956 to Dec, 1960. The lunar daily variations at any of the seasons or solar activity epochs are found to follow Chapman's phase law: L=Cn sin [n~+(.n-2)v+an]. With the increase of solar activity the phase of Ls wave remains constant for each of the seasons, but the amplitude increases during D. and E. months and slightly decreases during the months, The lunar semi monthly (.M2) waves at fixed solar hours vary with the solar time in the same way as the electrojet current, i.e., the amplitude starts increasing with sunrise reaches a maximum near noon and decreases to a low value by sunset. The ratio of lunar semidiurnal (LB} wave to the solar semidiurnal (82) wave for any of the seasons decreases with solar activity. The amplitudes of LB or M2 wave at Kodaikanal are much smaller than the corresponding values at Huancayo indicating the longitudinal variation in the lunar daytime effects in H along the magnetic equator. The lunar semimonthly tides for the daytime hours are predominantly under the control of lunar time during the D. months and of lunar age during the J .months.

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Li, Shuhui, Jiajia Xu, Houxiang Zhou, Jinglei Zhang, Zeyuan Xu, and Mingqiang Xie. "Global total electron content prediction performance assessment of the IRI-2016 model based on empirical orthogonal function decomposition." Annales Geophysicae 38, no. 2 (March 16, 2020): 331–45. http://dx.doi.org/10.5194/angeo-38-331-2020.

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Abstract. In this study, the empirical orthogonal function (EOF) decomposition technique was utilized to analyze the similarities and differences of the spatiotemporal characteristics between the total electron content (TEC) of the International GNSS Service global ionospheric map (GIM) and that derived from the International Reference Ionosphere 2016 (IRI-2016) model in 2013. Results showed that the main spatial patterns and time-varying features of the data set have good consistency. The following four main spatiotemporal variation features can be extracted from both data sets through EOF decomposition: the variation with the geomagnetic latitude reflecting the daily averaged solar forcing, the diurnal and semidiurnal periodic changes with longitude due to local time, and the interhemispheric asymmetry caused by the annual variation of the inclination angle of the Earth's orbit. The differences between the spatial patterns represented by the EOF base functions of IRI-2016 and GIM TECs were analyzed by extracting the same time-varying coefficients. The deviations of the interhemispheric asymmetry component between the two data sets showed roughly equal values throughout the Southern or Northern Hemisphere, whereas those of the other spatial modes were mainly concentrated on the equatorial region. The differences of the time-varying characteristics between the IRI-2016 and GIM TECs were also compared by extracting the same EOF base functions. Although the EOF coefficients of the two data sets presented consistent seasonal variations, the magnitude of IRI-2016 TEC changes over time was less than that of GIM TEC. The diurnal variation of the daily averaged solar forcing component and the annual variation of the interhemispheric asymmetry component exhibited relatively large deviations between the two data sets. Considering the variance contribution of the different EOF components and their average relative deviations, both analyses showed that the daily averaged solar forcing and interhemispheric asymmetry components were the main factors for the deviation between the IRI-2016 and GIM TECs.

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El-Borie, M. A. "Galactic cosmic-ray modulation effect by solar-wind streams." Canadian Journal of Physics 73, no. 9-10 (September 1, 1995): 642–46. http://dx.doi.org/10.1139/p95-094.

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Data, from the worldwide network of neutron monitors, recorded at Deep River, Hermanus, Rome, Tokyo, and Huancayo, over two solar cycles (Nos. 20 and 21) are analyzed to study the long-term variations of the solar diurnal variations as they relate to solar-wind speed. The median primary rigidities of response (Rm) for these detectors cover the range 16 GV ≤ Rm ≤ 33 GV. We discuss the solar diurnal variations (amplitude and phase) of cosmic rays as a function of solar activity. The behavior of solar diurnal phases is completely different for the two epochs of high-wind speed. Data of solar-wind speed from 1966–1986 are classified according to the state of the daily mean values. Variation in the amplitudes of the diurnal variations, as functions of the median primary rigidity of cosmic rays, for the two selected periods (1973–1975 and 1979–1981) of high and low solar-wind speeds were determined at the selected stations. The rigidity dependence of the averaged solar diurnal variations of cosmic rays related to the high solar-wind speed was studied. The most sensitive rigidity of modulation is around 20 and 30 GV during the 1973–1975 and 1979–1981 periods, respectively. Our results also show that there is a significant correlation in the solar diurnal amplitudes between the two divisions of high and low solar-wind speed days.

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Rayamajhi, Kamal Bahadur. "Estimation of Daily and Weekly Variation of Global Solar Radiation in Banbatika Park." Butwal Campus Journal 2, no. 1 (April 1, 2020): 13–17. http://dx.doi.org/10.3126/bcj.v2i1.35665.

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Pop, M. I. "Distribution of the Daily Sunspot Number Variation for the Last 14 Solar Cycles." Solar Physics 276, no. 1-2 (November 8, 2011): 351–61. http://dx.doi.org/10.1007/s11207-011-9871-x.

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Ahluwalia, H. S., and M. M. Fikani. "Upper limit for fourth harmonic of cosmic ray solar daily variation: 1963–2015." Advances in Space Research 59, no. 8 (April 2017): 2192–95. http://dx.doi.org/10.1016/j.asr.2017.01.043.

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Gelani, Hasan, Faizan Dastgeer, Kiran Siraj, Mashood Nasir, Kamran Niazi, and Yongheng Yang. "Efficiency Comparison of AC and DC Distribution Networks for Modern Residential Localities." Applied Sciences 9, no. 3 (February 11, 2019): 582. http://dx.doi.org/10.3390/app9030582.

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The paper investigates the system efficiency for power distribution in residential localities considering daily load variations. Relevant system modeling is presented. A mathematical model is devised, which is based on the data from the Energy Information Administration (EIA), USA, for analysis. The results reveal that the DC distribution system can present an equivalent or even better efficiency compared to the AC distribution network with an efficiency advantage of 2.3%, averaged over a day. Furthermore, the distribution systems are compared under various capacities of solar PV accounting for the effect of variation in solar irradiation over time.

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MISHRA, REKHA AGARWAL, and RAJESH K. MISHRA. "PERIODICITY IN DAILY VARIATION OF COSMIC RAY INTENSITY AS AN EFFECT OF SOLAR POLOIDAL MAGNETIC FIELD ORIENTATION." International Journal of Modern Physics D 13, no. 02 (February 2004): 253–62. http://dx.doi.org/10.1142/s0218271804004657.

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A detailed analysis of the Deep River neutron monitor (NM) data for four different phases of solar activity cycle and for four groups of days chosen according to their different geomagnetic conditions is being carried out. It is found that the 60 quiet day (QD) in a year serve a better purpose for investigating the short/long term variation in cosmic ray (CR) intensity. Furthermore, data has been harmonically analysed for the period 1964–95 to investigate the effect of solar poloidal magnetic field (SPMF) orientation in daily variation (diurnal/semi-diurnal) of CR on geomagnetically QD. The phase of the diurnal and semi-diurnal anisotropy vectors on QD has shown a significant shift to early hours when the SPMF in the northern hemisphere (NH) is positive during the periods 1971–79 and 1992–95 as compared to that during the periods 1964–70 and 1981–90 when the SPMF in NH is negative, showing a periodic nature of daily variation in CR intensity with SPMF.

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Crocker, William C., and Hong Zhang. "Seasonal and Diurnal Variation of Air/Water Exchange of Gaseous Mercury in a Southern Reservoir Lake (Cane Creek Lake, Tennessee, USA)." Water 12, no. 8 (July 24, 2020): 2102. http://dx.doi.org/10.3390/w12082102.

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A year-long field study of mercury (Hg) air/water exchange was conducted at a southern reservoir lake, Cane Creek Lake (Cookeville, TN, USA). The Hg air/water exchange fluxes and meteorological data including solar radiation (global solar radiation, Rg and ultraviolent radiation, UVA), water and air temperatures, relative humidity, and wind speed were collected to study the daily and seasonal trends of the Hg air/water exchange at the lake in relation to solar radiation and wind speed. The Hg exchange fluxes generally exhibited diurnal patterns with a rise in the morning, a peak around noontime, and a fall in the afternoon through the evening, closely following the change of solar radiation. There were cases that deviated from this general daily trend. The Hg emission fluxes were all below 3 ng m−2 h−1 with the daily mean fluxes < 2 ng m−2 h−1. The fluxes in the summer (mean: 1.2 ng m−2 h−1) were higher than in the fall (mean: 0.6 ng m−2 h−1) and winter (mean: 0.7 ng m−2 h−1). The daily and seasonal trends of the Hg air/water exchange fluxes are similar to the trends of the changes of the dissolved gaseous mercury (DGM) concentrations in the lake observed in our previous study. Solar radiation was found to exert a primary control over the Hg air/water exchange, while wind speed appeared to have a secondary effect on the Hg exchange. The two-thin-film model was used to calculate Hg emission fluxes from the Cane Creek Lake water.

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41

Li, Lei, Tao Chen, Shuo Ti, Shi-Han Wang, Jia-Jun Song, Chun-Lin Cai, Yong-Hua Liu, Wen Li, and Jing Luo. "Fair-Weather Near-Surface Atmospheric Electric Field Measurements at the Zhongshan Chinese Station in Antarctica." Applied Sciences 12, no. 18 (September 15, 2022): 9248. http://dx.doi.org/10.3390/app12189248.

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The variability in the atmospheric electric field is modulated by a combination of solar activities, meteorological activities, and geological conditions. A foundational dataset of the daily variations in the fair-weather atmospheric electric field is established in this study, and several examinations are conducted into the details of these variations in particular regions. This paper is organized as follows. First, the researchers count the datasets of daily variations to the atmospheric electric field on fair-weather days from 1 March–1 August 2022 at Zhongshan Chinese Station in Antarctica and Changping Station in Beijing. Then, the average daily variation in the atmospheric electric field on 40 fair-weather days in Antarctica is shown and the variations are compared with the average curve of 37 fair-weather days in Beijing during the same time period. Finally, the three main differences between these variations, their possible reasons, and a reasonable error analysis are clarified and discussed at the end of this paper.

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42

Shrestha, P. M., N. P. Chapagain, I. B. Karki, and K. N. Poudyal. "Variation on Atmospheric Transmittance Solar Radiation at Kathmandu Valley." Journal of Nepal Physical Society 6, no. 1 (August 8, 2020): 105–12. http://dx.doi.org/10.3126/jnphyssoc.v6i1.30558.

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The daily solar irradiance was measured using CMP6 first class pyranometer at the horizontal surface of Kathmandu Valley (Lat.:-27.7° N, Long.:-85.5° E, Alt. 1350 m above sea level.) from January to December, 2012 (one year). Monthly mean of atmospheric transmittance is calculated based on different meteorological parameters. The effect of different meteorological parameters as well as physical parameters on the atmospheric transmittance of solar radiation was analyzed. The maximum and the minimum monthly mean solar radiation are found to be 21.32 ± 4.14 MJ/m2/day and 10.93 ± 2.03 MJ/m2/day in May and January, respectively. The value of yearly mean solar radiation measures is 16.68 ± 4.60 MJ/m2/day. Similarly, the annual average of atmospheric transmittance value of 0.51 ± 0.12 was obtained that was due to cloudy and more precipitation day during the months of measurements taken. The yearly mean of atmospheric transmittance 0.983, 0.987, 0.698 and 0.889 are found due to Rayleigh scattering followed by ozone, water vapor, gas mixture and aerosols respectively, the maximum atmospheric transmittance due to water vapor and while minimum due to gas mixture. This research work will be beneficial for the further identification of other affecting factors of different parameters for the interaction with radiation at different places of the country.

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43

Zhang, Yao, Joanna Joiner, Seyed Hamed Alemohammad, Sha Zhou, and Pierre Gentine. "A global spatially contiguous solar-induced fluorescence (CSIF) dataset using neural networks." Biogeosciences 15, no. 19 (October 2, 2018): 5779–800. http://dx.doi.org/10.5194/bg-15-5779-2018.

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Abstract. Satellite-retrieved solar-induced chlorophyll fluorescence (SIF) has shown great potential to monitor the photosynthetic activity of terrestrial ecosystems. However, several issues, including low spatial and temporal resolution of the gridded datasets and high uncertainty of the individual retrievals, limit the applications of SIF. In addition, inconsistency in measurement footprints also hinders the direct comparison between gross primary production (GPP) from eddy covariance (EC) flux towers and satellite-retrieved SIF. In this study, by training a neural network (NN) with surface reflectance from the MODerate-resolution Imaging Spectroradiometer (MODIS) and SIF from Orbiting Carbon Observatory-2 (OCO-2), we generated two global spatially contiguous SIF (CSIF) datasets at moderate spatiotemporal (0.05∘ 4-day) resolutions during the MODIS era, one for clear-sky conditions (2000–2017) and the other one in all-sky conditions (2000–2016). The clear-sky instantaneous CSIF (CSIFclear-inst) shows high accuracy against the clear-sky OCO-2 SIF and little bias across biome types. The all-sky daily average CSIF (CSIFall-daily) dataset exhibits strong spatial, seasonal and interannual dynamics that are consistent with daily SIF from OCO-2 and the Global Ozone Monitoring Experiment-2 (GOME-2). An increasing trend (0.39 %) of annual average CSIFall-daily is also found, confirming the greening of Earth in most regions. Since the difference between satellite-observed SIF and CSIF is mostly caused by the environmental down-regulation on SIFyield, the ratio between OCO-2 SIF and CSIFclear-inst can be an effective indicator of drought stress that is more sensitive than the normalized difference vegetation index and enhanced vegetation index. By comparing CSIFall-daily with GPP estimates from 40 EC flux towers across the globe, we find a large cross-site variation (c.v. = 0.36) of the GPP–SIF relationship with the highest regression slopes for evergreen needleleaf forest. However, the cross-biome variation is relatively limited (c.v. = 0.15). These two contiguous SIF datasets and the derived GPP–SIF relationship enable a better understanding of the spatial and temporal variations of the GPP across biomes and climate.

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44

Arifin, Lukman, and John Maspupu. "MODEL EMPIRIS HARI TENANG VARIASI MEDAN GEOMAGNET DI STASIUN GEOMAGNET TONDANO MANADO." JURNAL GEOLOGI KELAUTAN 12, no. 2 (February 16, 2016): 115. http://dx.doi.org/10.32693/jgk.12.2.2014.251.

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Penentuan model empiris hari tenang variasi medan geomagnet dikonstruksi berdasarkan data geomagnet dari stasiun geomagnet (SG) Badan Meteorologi Klimatologi dan Geofisika (BMKG) Tondano, Manado. Hari tenang variasi medan geomagnet dinyatakan sebagai fungsi dari keempat komponen atau variabel yang mempengaruhinya yaitu: aktivitas matahari SA (solar activity), hari dalam setahun DOY (date of year), usia bulan LA (lunar age) dan waktu lokal LT (local time). Dalam bentuk matematis ditulis sebagai, EMQD ( SA, DOY, LA, LT ) = f(SA). g(DOY). h(LA). m(LT). Model empiris yang didasarkan pada fungsi kecocokan ini terdiri dari 270 bentuk ekspresi matematik. Sedangkan bentuk-bentuk ekspresi matematik ini juga mencakup proses-proses non-linier yang tak dapat diabaikan dalam model empiris hari tenang variasi medan geomagnet tersebut. Model empiris ini dapat ditiru atau dikonstruksi kembali pada suatu selang waktu yang relatif panjang (misalnya satu siklus matahari), asalkan kondisi geomagnet selalu berada dalam keadaan tenang. Kontribusi dari model empiris hari tenang ini akan memberikan informasi tentang gangguan geomagnet yang ada di stasiun geomagnet Tondano (Nilai Gangguan geomagnet = Nilai variasi medan geomagnet yang terukur â€“ Nilai model empiris hari tenang). Dengan demikian model ini akan memberikan informasi gangguan geomagnet untuk operasi survey geomagnet disekitar stasiun geomagnet Tondano, Manado. Kata kunci : Model empiris, Hari tenang, Variasi medan geomagnet. The determination an empirical model of the quiet daily geomagnetic field variation that is constructed based on geomagnetic data from Tondano, Manado station geomagnetic This quiet daily of geomagnetic field variation was described as a function of four variables that its influence, these are solar activity (SA), day of year (DOY), lunar age (LA) and local time (LT). In the mathematically writes: EMQD ( SA, DOY, LA, LT ) = f(SA). g(DOY). h(LA). m(LT). The empirical model based on this fitting function consist of 270 coefficients which included in expression form of mathematic. While, expression form of this mathematic also comprise nonlinear processes which can not minimized in the empirical model of the quiet daily geomagnetic field variation. This empirical model can be reconstructed on the time interval that is long relative (for example one solar cycle). Provided that, under geomagnetic quiet conditions. Contribution of this empirical model of the quiet daily variation is can give information about the existence of geomagnetic disturbance at Tondano (value of geomagnetic disturbance equal value of measurable geomagnetic field variation minus value of empirical model of the quiet daily variation). Thus, information about the existence of this geomagnetic disturbance very useful for necessity geomagnetic survey at Tondano, Manado geomagnetic station. Keywords: Empirical model, the quiet daily variation, geomagnetic field variation.

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Muller, R., A. Hanslmeier, D. Utz, and K. Ichimoto. "Does the solar granulation change with the activity cycle?" Astronomy & Astrophysics 616 (August 2018): A87. http://dx.doi.org/10.1051/0004-6361/201732085.

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Context. Knowledge of the variation of the solar granulation properties (contrast and scale) with the 11-yr activity cycle is useful for a better understanding of the interaction between magnetic field and convection at global or local scales. A varying granulation may also contribute to irradiance variations and affect the p-mode damping rates and lifetimes. Aims. HINODE/SOT blue continuum images taken in the frame of the synoptic program at the disk center on a daily basis between November 2006 and February 2016 are used. This period covers the minimum of activity between cycles 23 and 24 and the maximum of cycle 24. Methods. The sharpness of a significant number of images was reduced because of instrumental aberrations or inaccurate focusing. Only the sharpest images were selected for this investigation. Results. To be detectable with HINODE/SOT images, the variation of the granulation contrast and of the granulation scale at the disk center should have been larger than 3%. As it is not the case, it is concluded that they varied by less than 3% through the weak cycle 24.

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Singh, Vivek Kumar, Satish Chandra, Sanish Thomas, Som Kumar Sharma, and Hari Om Vats. "Radial differential rotation of solar corona using radio emissions." Monthly Notices of the Royal Astronomical Society: Letters 505, no. 1 (May 3, 2021): L16—L20. http://dx.doi.org/10.1093/mnrasl/slab042.

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ABSTRACT The present work is an effort to investigate possible radial variations in the solar coronal rotation by analysing the solar radio emission data at 15 different frequencies (275–1755 MHz) for the period starting from 1994 July to 1999 May. We used a time series of disc-integrated radio flux recorded daily at these frequencies through radio telescopes situated at the Astronomical Observatory of the Jagellonian University in Cracow. The different frequency radiation originates from different heights in the solar corona. Existing models indicate its origin at the height range from nearly ∼12 000 km (for emission at 275 MHz), below up to ∼2400 km (for emission at 1755 MHz). There are some data gaps in the time series used for the study, so we used statistical analysis using the Lomb–Scargle periodogram (LSP). This method has successfully estimated the periodicity present in time series even with such data gaps. The rotation period estimated through LSP shows variation in the rotation period, which is compared with the earlier reported estimate using auto correlation technique. This study indicates some similarity as well as a contradiction with studies reported earlier. The radial and temporal variation in the solar rotation period are presented and discussed for the whole period analysed.

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Tully, N. "Short-Term Performance of Integral Solar Water Heaters." Journal of Solar Energy Engineering 108, no. 1 (February 1, 1986): 6–10. http://dx.doi.org/10.1115/1.3268067.

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The 8-hr daily test of solar integral or collector/storage domestic water heaters is considered. For the case of no draw-off, it is shown that a computer simulation gives results closely in agreement with an integral equation which involves the collector parameters, the total insolation and the daily temperation variation, but does not require the actual daily ambient temperature. The relationship of this test to integral unit performance when water is drawn off according to various demand patterns is investigated, and it is shown that the short-term efficiency is typically reduced to two thirds of the daily test result, but can be as low as one third. Thus a simple thermal test such as that specified by the South African Bureau of Standards, and other standards organizations, should at best be regarded as a comparison between various units of similar type, although even there the importance of optical efficiency is overemphasized. Simple tests do not provide a guide to performance in actual service.

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Mishra, Rekha Agarwal, and Rajesh K. Mishra. "Effect of solar heliospheric parameters on different components of daily variation in cosmic rays." Earth, Moon, and Planets 100, no. 3-4 (March 2, 2007): 181–94. http://dx.doi.org/10.1007/s11038-007-9136-8.

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Oudrane, A., B. Aour, B. Zeghmati, X. Chesneau, and H. Massaoud. "Study and Simulation of the Density of the Incident Solar Flux on the Walls of a Building in Adrar, Algeria." Engineering, Technology & Applied Science Research 7, no. 5 (October 19, 2017): 1940–45. http://dx.doi.org/10.48084/etasr.1337.

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In this work, we studied the effect of external climatic conditions on the evolution of the daily solar flux incident on the walls of a building located at Adrar region in the South of Algeria. This building is designed for heating or air conditioning applications. Numerical simulations allowed to compare the variation of the incident solar flux over a full day on the south, east, north and west walls of the building to the values of the solar flux on a horizontal wall (the outer ceiling). The horizontal global solar flux is calculated using a Gaussian sinusoidal function. The simulations were carried out in the case of a building located in a desert zone. The results of the numerical simulation showed the effect of the orientation of the building on the evolution of the incident daily solar flux.

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Lopes Júnior, José Marcelo, José Leonaldo de Souza, Ricardo Araujo Ferreira Junior, Cícero Manoel dos Santos, Gustavo Bastos Lyra, Chigueru Tiba, and Rosiberto Salustiano da Silva Júnior. "Analysis of Measurements of Direct Normal and Global Solar Radiation for Maceió, Alagoas State, Northeastern Brazil." Revista Brasileira de Meteorologia 35, no. 4 (December 2020): 659–74. http://dx.doi.org/10.1590/0102-77863540070.

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Abstract Studying solar radiation is essential for human knowledge, since it is present in practically all its activities. Thus, the aim of this work was to analyze the climatic and seasonal variation of direct normal and global solar radiation in the region of Maceió, Alagoas State, Northeastern Brazil with sky conditions characterized by clearness index (Kt). The Kt was determined by the ratio between global solar irradiance and solar irradiance at the top of the atmosphere. The highest occurrences of daily direct normal solar irradiance under conditions of Kt ≥ 0.6 were recorded between 400 W m−2 and 700 W m−2 for all seasons. Under conditions of 0.4 ≤ Kt < 0.6, the daily direct normal solar irradiance occurred between 200 W m−2 and 500 W m−2 and for conditions of Kt < 0.4, its maximum value was 200 W m−2. It was observed that the levels of solar incidence in the study region depend on cloud cover conditions, with little influence of seasonality.

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Journal articles on the topic 'Solar daily variation'

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