Climate Features of Dakhla Oasis
91
in the climatic environment in the upper reaches of the Nile around 3,500 BC, 2,000
BC, 200 BC, AD 450, AD 1,000, and AD 1,700 (Shinoda 2009).
The natural vegetation of the current Sahara is uncommon to the African region,
but shares deep commonalities with the central Eurasian Continent. Thus, the biology
in the Sahara Desert completed the process of differentiation relative to the arid
regions from central Eurasia to northern Africa during the Tertiary to Quaternary
eras (Mizuno 2005).
3 Overview of the Climate in Egypt Today
The current Egyptian climate is featured by a hot (March to September) and
cold seasons (October to February), although the northerly prevailing winds called
Harmattan keep temperatures relatively moderate. In the coastal regions along the
Red and Mediterranean seas, the average annual temperatures range from 14 °C to
37 °C. The wettest area is along the Mediterranean coast, where the average annual
rainfall is about 200 mm. Rainfall decreases drastically towards the south where it
might rain only once every several years in many desert areas (Robaa 2008). Temperatures change largely in the desert regions. In the summer, the diurnal range is from
7 °C at night to 43 °C at daytime. Temperatures fluctuate less in winter, but they are
still be from 0 °C at night to 18 °C at daytime (Robaa 2008). Annual temperature
increases southward from the Nile Delta to the Sudanese border (Metz 1990: http://
countrystudies.us/egypt/53.htm).
The solar radiation is 12 to 30 MJ/m
2 /day, and the sunshine duration is from 3500
to 4500 h/year (Tadros 2000). Egypt is featured by fine skies during the summer (June
to August) and partly cloudy skies during the spring (March to May) and autumn
(September to November) (Robaa 2008). In the winter, Egypt is featured by cloudy
skies, but cloud cover decreases from north to south.
Hot springs winds, known to Egyptians as the Khamsin wind and to Europeans
as the Sirocco wind, characteristically blow across the country. Khamsin arrive in
April, but sometimes occur in March or May (Robaa 2008). Because of the lack of
geographical features to obstruct them, the winds reach high velocities (up to 39 m/s
from the south or southeast) and transport great deal of sand or dust from the deserts.
These sand or dust storms cause temperatures to increase by 20 °C in as little as 2 h.
The winds can continue for days, and cause health problems for both human and
animals (Robaa 2008).
4 Climatic Characteristics of Dakhla Oasis
Climate in Dakhla Oasis is under the control of the Harmattan dry wind, which is
a dry wind (6–14 m/s) that blows hot air from the Sahara due to a subtropical high
pressure center called the “Azores High,” causing an oasis effect. Thus, the Dakhla
Oasis climate has characteristics that are typical of both desert and oasis, including:
91
in the climatic environment in the upper reaches of the Nile around 3,500 BC, 2,000
BC, 200 BC, AD 450, AD 1,000, and AD 1,700 (Shinoda 2009).
The natural vegetation of the current Sahara is uncommon to the African region,
but shares deep commonalities with the central Eurasian Continent. Thus, the biology
in the Sahara Desert completed the process of differentiation relative to the arid
regions from central Eurasia to northern Africa during the Tertiary to Quaternary
eras (Mizuno 2005).
3 Overview of the Climate in Egypt Today
The current Egyptian climate is featured by a hot (March to September) and
cold seasons (October to February), although the northerly prevailing winds called
Harmattan keep temperatures relatively moderate. In the coastal regions along the
Red and Mediterranean seas, the average annual temperatures range from 14 °C to
37 °C. The wettest area is along the Mediterranean coast, where the average annual
rainfall is about 200 mm. Rainfall decreases drastically towards the south where it
might rain only once every several years in many desert areas (Robaa 2008). Temperatures change largely in the desert regions. In the summer, the diurnal range is from
7 °C at night to 43 °C at daytime. Temperatures fluctuate less in winter, but they are
still be from 0 °C at night to 18 °C at daytime (Robaa 2008). Annual temperature
increases southward from the Nile Delta to the Sudanese border (Metz 1990: http://
countrystudies.us/egypt/53.htm).
The solar radiation is 12 to 30 MJ/m
2 /day, and the sunshine duration is from 3500
to 4500 h/year (Tadros 2000). Egypt is featured by fine skies during the summer (June
to August) and partly cloudy skies during the spring (March to May) and autumn
(September to November) (Robaa 2008). In the winter, Egypt is featured by cloudy
skies, but cloud cover decreases from north to south.
Hot springs winds, known to Egyptians as the Khamsin wind and to Europeans
as the Sirocco wind, characteristically blow across the country. Khamsin arrive in
April, but sometimes occur in March or May (Robaa 2008). Because of the lack of
geographical features to obstruct them, the winds reach high velocities (up to 39 m/s
from the south or southeast) and transport great deal of sand or dust from the deserts.
These sand or dust storms cause temperatures to increase by 20 °C in as little as 2 h.
The winds can continue for days, and cause health problems for both human and
animals (Robaa 2008).
4 Climatic Characteristics of Dakhla Oasis
Climate in Dakhla Oasis is under the control of the Harmattan dry wind, which is
a dry wind (6–14 m/s) that blows hot air from the Sahara due to a subtropical high
pressure center called the “Azores High,” causing an oasis effect. Thus, the Dakhla
Oasis climate has characteristics that are typical of both desert and oasis, including: