Papers by Abdulaziz Maghrabi
Energy Conversion and Management, 2009
We have developed simple single pixel thermopile infrared (IR) detectors for monitoring clouds fo... more We have developed simple single pixel thermopile infrared (IR) detectors for monitoring clouds for the purpose of atmospheric research and for cloud detection over astronomical and astrophysical observatories. Those detectors were developed with 3°and 90°fields of view (FOV) and have a broad spectral response extended from 5.5 lm to above 20 lm centered on a wavelength of 10 lm.
Energy Conversion and Management, 2011
ABSTRACT
Journal of Geophysical Research, 2005
1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coa... more 1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coastal region of South Australia. The long-term aim of this work is to be able to use measurements of the sky temperature, plus other readily measured ground-based parameters, to recognize the presence, or otherwise, of clouds. Comparisons have been made between the 10 mm sky temperature and cloud height in overcast conditions, measured both with a ceilometer and radiosondes. A low-altitude cloud exhibits a wide range of emissivities, such that clouds with base heights up to 1200 m have emissivities ranging from below 0.2 to close those expected for black bodies at those wavelengths. However, higher clouds exhibit different properties, as their temperatures approach those to be expected for a clear sky with water vapor.
Meteorological Applications, 2009
Precipitable water vapour (PWV) is an important component of the atmosphere, but remains difficul... more Precipitable water vapour (PWV) is an important component of the atmosphere, but remains difficult to measure with adequate spatial and temporal resolution under all weather conditions. Over the last four decades several techniques and methods have been developed to measure PWV more accurately, but each carries limitations preventing its widespread use. This paper presents preliminary results of a simple method for inferring PWV from the air temperature and infrared (IR) sky temperature under clear skies. Sky temperatures are measured using a broadband, single-pixel IR radiometer. A parametric model of the physical relationship between these three quantities was created using PWV data derived from a GPS receiver. By inverting the model, PWV estimates can be obtained from new temperature measurements. The measurements were taken between October 2002 and July 2004 in a coastal region of South Australia. The method was found to predict PWV quite accurately, with a mean bias error (MBE) of only − 0.009 mm and a root mean square error (RMSE) of 2.311 mm. The model was also compared to a set of 120 radiosonde-derived PWV values, resulting in a MBE and RMSE of 0.262 and 2.601 mm respectively. These preliminary results show that the clear sky PWV can be estimated accurately from sky temperatures obtained using a simple IR detector. Future work will extend the method to different sky and weather conditions. Copyright © 2009 Royal Meteorological Society
Journal of Geophysical Research, 2005
1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coa... more 1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coastal region of South Australia. The long-term aim of this work is to be able to use measurements of the sky temperature, plus other readily measured ground-based parameters, to recognize the presence, or otherwise, of clouds. Comparisons have been made between the 10 mm sky temperature and cloud height in overcast conditions, measured both with a ceilometer and radiosondes. A low-altitude cloud exhibits a wide range of emissivities, such that clouds with base heights up to 1200 m have emissivities ranging from below 0.2 to close those expected for black bodies at those wavelengths. However, higher clouds exhibit different properties, as their temperatures approach those to be expected for a clear sky with water vapor.
Energy Conversion and Management, 2009
We have developed simple single pixel thermopile infrared (IR) detectors for monitoring clouds fo... more We have developed simple single pixel thermopile infrared (IR) detectors for monitoring clouds for the purpose of atmospheric research and for cloud detection over astronomical and astrophysical observatories. Those detectors were developed with 3°and 90°fields of view (FOV) and have a broad spectral response extended from 5.5 lm to above 20 lm centered on a wavelength of 10 lm.
Energy Conversion and Management, 2011
ABSTRACT
Journal of Geophysical Research, 2005
1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coa... more 1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coastal region of South Australia. The long-term aim of this work is to be able to use measurements of the sky temperature, plus other readily measured ground-based parameters, to recognize the presence, or otherwise, of clouds. Comparisons have been made between the 10 mm sky temperature and cloud height in overcast conditions, measured both with a ceilometer and radiosondes. A low-altitude cloud exhibits a wide range of emissivities, such that clouds with base heights up to 1200 m have emissivities ranging from below 0.2 to close those expected for black bodies at those wavelengths. However, higher clouds exhibit different properties, as their temperatures approach those to be expected for a clear sky with water vapor.
Meteorological Applications, 2009
Precipitable water vapour (PWV) is an important component of the atmosphere, but remains difficul... more Precipitable water vapour (PWV) is an important component of the atmosphere, but remains difficult to measure with adequate spatial and temporal resolution under all weather conditions. Over the last four decades several techniques and methods have been developed to measure PWV more accurately, but each carries limitations preventing its widespread use. This paper presents preliminary results of a simple method for inferring PWV from the air temperature and infrared (IR) sky temperature under clear skies. Sky temperatures are measured using a broadband, single-pixel IR radiometer. A parametric model of the physical relationship between these three quantities was created using PWV data derived from a GPS receiver. By inverting the model, PWV estimates can be obtained from new temperature measurements. The measurements were taken between October 2002 and July 2004 in a coastal region of South Australia. The method was found to predict PWV quite accurately, with a mean bias error (MBE) of only − 0.009 mm and a root mean square error (RMSE) of 2.311 mm. The model was also compared to a set of 120 radiosonde-derived PWV values, resulting in a MBE and RMSE of 0.262 and 2.601 mm respectively. These preliminary results show that the clear sky PWV can be estimated accurately from sky temperatures obtained using a simple IR detector. Future work will extend the method to different sky and weather conditions. Copyright © 2009 Royal Meteorological Society
Journal of Geophysical Research, 2005
1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coa... more 1] We have studied the 10 mm temperature of overcast skies, as measured from the ground, in a coastal region of South Australia. The long-term aim of this work is to be able to use measurements of the sky temperature, plus other readily measured ground-based parameters, to recognize the presence, or otherwise, of clouds. Comparisons have been made between the 10 mm sky temperature and cloud height in overcast conditions, measured both with a ceilometer and radiosondes. A low-altitude cloud exhibits a wide range of emissivities, such that clouds with base heights up to 1200 m have emissivities ranging from below 0.2 to close those expected for black bodies at those wavelengths. However, higher clouds exhibit different properties, as their temperatures approach those to be expected for a clear sky with water vapor.
Atmospheric Environment, 2011
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Papers by Abdulaziz Maghrabi