Document Details
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Document Type |
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Article In Journal |
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Document Title |
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Results of Outgoing Longwave Radiation and Albedo over Saudi Arabia from Earth Radiation Budget Experiment (ERBE) Data نتائج الأشعة ذات الموجات الطويلة المنبعثة ونسبة الانعكاسية فوق المملكة العربية السعودية من بيانات تجربة ميزانية الإشعاع الأرضي |
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Document Language |
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English |
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Abstract |
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ABSTRACT. Changes in the albedo and outgoing longwave radiation at
the top of the atmosphere derived from Earth Radiation Budget Experiment
(ERBE) are specified as a function of atmospheric (all sky conditions)
and surface properties (clear sky conditions). Albedo and
outgoing longwave radiation observations are also used to relate cloudiness
variations to regional features of the general circulations such as
precipitation zones, persistent cloudiness, and areas of subsidence. A
method requiring only measurements of outgoing long wave radiation
and planetary albedo is applied to evaluate the relative importance of
the albedo and long wave radiation on the atmospheric circulation. The
approach of studying these observations in time and space is also used
to examine the radiative energy budget of different geographic locations
such as deserts, high land, and coastal areas. The results indicate
that there are clear relationships between the variability in outgoing
longwave radiation, albedo, and features of the atmospheric circulation,
which appear to be linked to changes in cloudiness. In addition, the effect
of geographical variations of Saudi Arabia on cloud is analyzed
and related to circulation features. The longwave mean ranges from
257.1 Wm.2 to 307.7 Wm.2, and the longwave standard deviation ranges
from 10.6 Wm.2 to 27.9 Wm.2 over the region. The albedo mean
ranges from 20.9% to 30.6%, and the albedo standard deviation ranges
from 5.5% to 8.7% over the region. The longwave cloud forcing at the
top of the atmosphere equals 15 Wm.2 for January, 22 Wm.2 for April,
14 Wm.2 for July, and 10 Wm.2 for October 1989. Thus compared to a
cloud free atmosphere, the January mean cloudiness, as it was present,
reduces the outgoing longwave radiation for the total earth-atmosphere
system by about 6%, for the month of April by about 8%, for the month
of July by about 5%, and for the month of October by about 3%. For
clear sky desert conditions, a weak relationship (R2 = 0.38) between the
albedo and outgoing longwave radiation was found at some locations
over the Kingdom. Whereas the relationship between all sky albedo
and all sky outgoing longwave radiation results in a strong relationship
(R2 = 0.80) at some locations. |
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ISSN |
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1319-1039 |
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Journal Name |
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Meteorology, Environment and Arid Land Agriculture Sciences Journal |
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Volume |
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17 |
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Issue Number |
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1 |
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Publishing Year |
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1427 AH
2006 AD |
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Article Type |
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Article |
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Added Date |
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Friday, June 1, 2012 |
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Researchers
| عبدالرحمن خلف الخلف | AL-KHALAF, A K | Investigator | Doctorate | akhalaf@kau.edu.sa |
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