scholarly journals Interference between Total Solar Radiation and Cloud Cover over Baghdad City

2021 ◽  
Vol 2114 (1) ◽  
pp. 012070
Author(s):  
OsamaT. Al-Taai ◽  
Shiemaa A. Hashim ◽  
Wedyan G. Nassif ◽  
Zainab M. Abbood
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Inverse Relationship ◽  
Horizontal Surface ◽  
Total Solar Radiation ◽  
Annual Data ◽  
Total Cloud Cover ◽  
Weather Forecasts ◽  
Medium Range ◽  
The Relationship

Abstract Clouds greatly affect the elements of climate, energy balance, and solar radiation, which has increased the interest of many researchers in trying to find the best relationships and formulas that link these variables. In this work, the data of the European Center for Medium-Range Weather Forecasts (ECMWF) was relied on. The research aims to find the overlap between Cloud Cover (Low, Middle, High, and Total), (LCC, MCC, HCC, and TCC) respectively, with Total Solar Radiation (TSR) of Baghdad city, for the period (1981-2013), the work was carried out with the monthly and annual data of the (Low, Middle, High, and Total) cloud cover and the total solar radiation falling on a horizontal surface. And by using the correlation coefficient Spearman rho test (rs) to find the strength of the relationship between total solar radiation and cloud cover, it was found that there is an inverse relationship between the total solar radiation falling on a horizontal surface and the (Low, Middle, High, and Total) cloud cover.

Discrete Postprocessing of Total Cloud Cover Ensemble Forecasts

2016 ◽  
Vol 144 (7) ◽  
pp. 2565-2577 ◽  
Author(s):  
Stephan Hemri ◽  
Thomas Haiden ◽  
Florian Pappenberger
Keyword(s):  
Logistic Regression ◽  
Regression Model ◽  
Cloud Cover ◽  
Logistic Regression Model ◽  
Multinomial Logistic Regression ◽  
Total Cloud Cover ◽  
Proportional Odds ◽  
Ensemble Forecasts ◽  
Weather Forecasts ◽  
Medium Range

Abstract This paper presents an approach to postprocess ensemble forecasts for the discrete and bounded weather variable of total cloud cover. Two methods for discrete statistical postprocessing of ensemble predictions are tested: the first approach is based on multinomial logistic regression and the second involves a proportional odds logistic regression model. Applying them to total cloud cover raw ensemble forecasts from the European Centre for Medium-Range Weather Forecasts improves forecast skill significantly. Based on stationwise postprocessing of raw ensemble total cloud cover forecasts for a global set of 3330 stations over the period from 2007 to early 2014, the more parsimonious proportional odds logistic regression model proved to slightly outperform the multinomial logistic regression model.

scholarly journals Analysis of the convective available potential energy by precipitation over Iraq using ECMWF data for the period of 1989–2018

2020 ◽  
Vol 29 (2) ◽  
pp. 196-211
Author(s):  
Osama Al-Taai ◽  
Zainab Abbood
Keyword(s):  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Weather Conditions ◽  
Convective Precipitation ◽  
Total Precipitation ◽  
Weather Forecasts ◽  
Available Potential Energy ◽  
Medium Range ◽  
The Relationship ◽  
Very High

The Convective Available Potential Energy (CAPE) represents the amount of energy for a sample of air. The sample departs vertically within the atmosphere and through these values the potential energy to predict the extreme weather conditions such as storms, hurricanes, lightning and thunder. Data are taken by CAPE, convective precipitation (Cp) and total precipitation (Tp) from satellites recorded by the European Centre for Medium-Range Weather Forecasts (ECMWF). The choice of 30 years (1989– –2018) over Iraq station between two latitudes (29.5°–37.22° N) and two longitudes (48.45°–38.45° E). Otherwise, we have studied total yearly mean of CAPE, Cp and Tp over Iraq, the total monthly mean of CAPE, Cp and Tp for the selected station, as well as the relationship between of CAPE, Cp and Tp for the selected station. The results showed that the highest total yearly mean of CAPE, Cp and Tp over Iraq was included northern stations and lowest was included central and southern stations. The highest total monthly mean of CAPE, Cp and Tp for Zakho station. The relationship between the CAPE and Cp is positive and the relationship between CAPE and Tp is positive too at five stations but Mosul station represents very high correlation while Zakho station represents the low correlation.

scholarly journals Solar Radiation Potential at Four Sites of Nepal

1970 ◽  
Vol 8 (3) ◽  
pp. 189-197 ◽  
Author(s):  
Khem N Pondyal ◽  
Binod K Bhattarai ◽  
Balkrishna Sapkota ◽  
Berit Kjeldstad
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Diurnal Variation ◽  
Sea Level ◽  
Air Pollutants ◽  
Calculated Data ◽  
Horizontal Surface ◽  
Total Solar Radiation ◽  
Annual Average ◽  
Clear Sky

The intensity of solar radiation available at the horizontal surface are measured by a CMP6 Pyranometer in Biratnagar (26.45°N, 87.27°E), Pokhara (28.22°N, 83.32°E), Kathmandu (27.72°N, 85.32°E ) and Lukla (26.69°N,86.73°E), which are 72m, 800m, 1350m, and 2850m, above from the sea level. This paper compares the seasonal and altitude variations of total solar radiation measured at above mentioned sites. The maximum total solar radiation of about 704.51 W/m2, 815.97 W/m2 777.27 W/m2 and 914.03 W/m2, are observed in Biratnagar, Pokhara, Kathmandu, and Lukla respectively. Solar radiation available in any location is affected by topography and pollution. It is found that the more solar energy is available during spring than in summer in Lukla. The solar radiation is observed higher in Pokhara than in Kathmandu. It might be due to absorption of solar energy by air pollutants which are higher in Kathmandu as compared to Pokhara.In addition we also discussed the diurnal variation of measured and calculated data of solar radiation on clear sky day. The annual average solar energy measuring 4.95, 5.44, 5.19 and 4.61 kWh/m2/day is found in Biratnagar, Pokhara Kathmandu and Lukla respectively. DOI: http://dx.doi.org/10.3126/jie.v8i3.5944 JIE 2011; 8(3): 189-197

scholarly journals Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces

2012 ◽  
Vol 32 (2) ◽  
pp. 247-260
Author(s):  
Adilson P. de Souza ◽  
João F. Escobedo ◽  
Alexandre Dal Pai ◽  
Eduardo N. Gomes
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Diffuse Radiation ◽  
Incident Radiation ◽  
Sao Paulo ◽  
Horizontal Surface ◽  
Direct Radiation ◽  
Incident Solar Radiation ◽  
Cover Ratio ◽  
Atmospheric Transmissivity

It was evaluated the annual evolution of global, direct and diffuse components of incident solar radiation on tilted surfaces to 12.85, 22.85 and 32.85º, facing north, in Botucatu, state of São Paulo, Brazil. The radiometric fractions were obtained for each component of the radiation in the aforementioned surfaces, through the ratio with the global and top of the atmosphere radiations. Seasonality was evaluated based on monthly averages of daily values. The measures occurred between 04/1998 and 07/2001 at 22.85º; 08/2001 and 02/2003 at 12.85º; and from 03/2003 to 12/2007 at 32.85º, with concomitant measures in the horizontal surface (reference). The levels of global and direct radiation on tilted surfaces were lower in summer and higher in the equinoxes when compared with the horizontal. The diffuse radiation on tilted surfaces was lower in most months, with losses of up to 65%. A trend of increasing differences occurred between horizontal and tilted surfaces with the increase of the angle in all the components and fractions of incident radiation. The annual evolution of rainfall and cloud cover ratio directly affected the atmospheric transmissivity of direct and diffuse components in the region.

scholarly journals Wavelet-Gaussian Process Regression Model for Regression Daily Solar Radiation in Ghardaia, Algeria

2021 ◽  
Vol 20 (2) ◽  
pp. 113-119
Author(s):  
Khaled Ferkous ◽  
Farouk Chellali ◽  
Abdalah Kouzou ◽  
Belgacem Bekkar
Keyword(s):  
Solar Radiation ◽  
Root Mean Square Error ◽  
Gaussian Process ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Gaussian Process Regression ◽  
Absolute Error ◽  
Horizontal Surface ◽  
Total Solar Radiation ◽  
Mean Square

Several methods have been used to predict daily solar radiation in recent years, such as artificial intelligence and hybrid models. In this paper, a Wavelet coupled Gaussian Process Regression (W-GPR) model was proposed to predict the daily solar radiation received on a horizontal surface in Ghardaia (Algeria). A statistical period of four years (2013 -2016) was used where the first three years (2013-2015) are used to train model and the last year (2016) to test the model for predicting daily total solar radiation. Different types of wave mother and different combinations of input data were evaluated based on the minimum air temperature, relative humidity and extraterrestrial solar radiation on a horizontal surface. The results demonstrated the effectiveness of the new hybrid model W-GPR compared to the classical GPR model in terms of Root Mean Square Error (RMSE), relative Root Mean Square Error (rRMSE), Mean Absolute Error (MAE) and determination coefficient (R2).

scholarly journals Studying the Changes in Solar Radiation and Their Influence on Temperature Trend in Iraq for a Whole Century

2021 ◽  
Vol 18 (2(Suppl.)) ◽  
pp. 1076
Author(s):  
Basim Abdulsada Al-Knani ◽  
Iqbal H. Abdulkareem ◽  
Hussain Abodi Nemah ◽  
Zahraa Nasir
Keyword(s):  
Solar Radiation ◽  
Inverse Relationship ◽  
Direct Solar Radiation ◽  
Sharp Drop ◽  
Temperature Levels ◽  
Year 2000 ◽  
The Relationship ◽  
The City ◽  
Over Time ◽  
Atmospheric Variables

Most studies indicated that the values ​​of atmospheric variables have changed from their general rates due to pollution or global warming etc. Hence, the research indicates the changes of direct solar radiation values ​​over a whole century i.e. from 1900 to 2000 depending on registered data for four cities, namely (Mosul - Baghdad - Rutba - Basra. Moreover, attemptsto correlate the direct solar radiation with the temperature values have been ​​recorded over that period. The results showed that there is a decreasing pattern of radiation quantities over time throughout the study period, where the value of direct radiation over the city of Baghdad 5550 w/m2 was recorded in the year 1900, but this ratio decreased clearly to approximately 5400 w/m2 in the year 2000, which is perhaps due to the increase of general pollution rates in the atmosphere. The results also showed that the city of Rutba recorded the highest annual rate of radiation quantities, and Baghdad with Mosul recorded the lowest radiation ratios compared to the rest of the cities, in addition to that there was a large convergence of radiation ratios between them to some extent. The results showed that there is a sharp drop in radiation ratios, specifically in the years1980and 1990. As for the extent of the relationship for solar radiation with temperature levels throughout the study period, it was found that there is an inverse relationship between them, and this confirms that the cause of high temperatures is not because of increased solar radiation, but it may rather due to other reasons such as increased greenhouse gases.

scholarly journals Origins of Dry Air in the Tropics and Subtropics

2007 ◽  
Vol 20 (12) ◽  
pp. 2745-2759 ◽  
Author(s):  
Piero Cau ◽  
John Methven ◽  
Brian Hoskins
Keyword(s):  
Potential Temperature ◽  
Lower Troposphere ◽  
Transport Processes ◽  
Air Masses ◽  
Weather Forecasts ◽  
Dry Air ◽  
Medium Range ◽  
Net Pressure ◽  
The Tropics ◽  
The Relationship

Abstract The humidity in the dry regions of the tropical and subtropical troposphere has a major impact on the ability of the atmosphere to radiate heat to space. The water vapor content in these regions is determined by their “origins,” here defined as the last condensation event following air masses. Trajectory simulations are used to investigate such origins using the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) data for January 1993. It is shown that 96% of air parcels experience condensation within 24 days and most of the remaining 4% originate in the stratosphere. Dry air masses are shown to experience a net pressure increase since last condensation, which is uniform with latitude, while the median time taken for descent is 5 days into the subtropics but exceeds 16 days into the equatorial lower troposphere. The associated rate of decrease in potential temperature is consistent with radiative cooling. The relationship between the drier regions in the Tropics and subtropics and the geographical localization of their origin is investigated. Four transport processes are identified to explain these relationships.

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