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R. Kimura
5 Conclusions
This chapter described climatic features in Dakhla Oasis and some climatic
differences between Dakhla and Kharga Oases. The main findings are as follows:
• Relative sunshine duration is generally very high, and annual precipitation is close
to 0 mm, with few exceptions.
• The aridity index AI (annual rainfall to potential evapotranspiration), used by the
UNEP (1997), indicated that this district lies in a hyper-arid region.
• The annual average, average maximum, and average minimum temperatures
(2007–2016) in Dakhla were 24.4, 32.9, and 15.9 °C, respectively. The daily
maximum and minimum temperatures were 42.5 and 4.4 °C, respectively. The
average diurnal amplitude was 16.9 °C, the maximum was 21.2 °C, and the
minimum was 12.4 °C.
• Wind speed is comparatively calm under the effects of high pressure. The annual
average relative humidity and vapor pressure (from 2007 to 2016) were 33% and
11 hPa, respectively. The comparatively high humidity, calm wind speed, and
low temperature cause a low evapotranspiration demand and can result in the
conservation of irrigation water.
• Temperature, wind speed, and annual ET p are lower in Dakhla Oasis as compared
with Kharga Oasis. Annual ET p in Dakhla Oasis is about 400 mm (1.1 mm/day)
lower than it is in Kharga Oasis.
6 Recommendations
• In this study, climate features of Dakhla Oasis were evaluated by using synoptic
meteorological data. These data have been accumulated continuously, so they
are valuable to monitor climate changes, for example, global warming. However,
additional meteorological stations are needed to manage irrigation water use in
oasis regions because local climate conditions differ, often as a result of local
geographic features.
• Use of satellite data may support efforts to monitor local climate conditions.
Satellite sensors such as the Moderate Resolution Imaging Spectroradiometer
(MODIS) can be used to monitor land surface temperature, vegetation indices,
evapotranspiration, and other important factors. Newer systems, such as the
Second Generation Global Imager (SGLI) sensor on the Global Change Observation Mission (Climate) satellite have a higher resolution (250 m) than MODIS,
and many kinds of channels and products. These satellite data can be used to cover
for the shortage of meteorological stations in Oasis regions.
R. Kimura
5 Conclusions
This chapter described climatic features in Dakhla Oasis and some climatic
differences between Dakhla and Kharga Oases. The main findings are as follows:
• Relative sunshine duration is generally very high, and annual precipitation is close
to 0 mm, with few exceptions.
• The aridity index AI (annual rainfall to potential evapotranspiration), used by the
UNEP (1997), indicated that this district lies in a hyper-arid region.
• The annual average, average maximum, and average minimum temperatures
(2007–2016) in Dakhla were 24.4, 32.9, and 15.9 °C, respectively. The daily
maximum and minimum temperatures were 42.5 and 4.4 °C, respectively. The
average diurnal amplitude was 16.9 °C, the maximum was 21.2 °C, and the
minimum was 12.4 °C.
• Wind speed is comparatively calm under the effects of high pressure. The annual
average relative humidity and vapor pressure (from 2007 to 2016) were 33% and
11 hPa, respectively. The comparatively high humidity, calm wind speed, and
low temperature cause a low evapotranspiration demand and can result in the
conservation of irrigation water.
• Temperature, wind speed, and annual ET p are lower in Dakhla Oasis as compared
with Kharga Oasis. Annual ET p in Dakhla Oasis is about 400 mm (1.1 mm/day)
lower than it is in Kharga Oasis.
6 Recommendations
• In this study, climate features of Dakhla Oasis were evaluated by using synoptic
meteorological data. These data have been accumulated continuously, so they
are valuable to monitor climate changes, for example, global warming. However,
additional meteorological stations are needed to manage irrigation water use in
oasis regions because local climate conditions differ, often as a result of local
geographic features.
• Use of satellite data may support efforts to monitor local climate conditions.
Satellite sensors such as the Moderate Resolution Imaging Spectroradiometer
(MODIS) can be used to monitor land surface temperature, vegetation indices,
evapotranspiration, and other important factors. Newer systems, such as the
Second Generation Global Imager (SGLI) sensor on the Global Change Observation Mission (Climate) satellite have a higher resolution (250 m) than MODIS,
and many kinds of channels and products. These satellite data can be used to cover
for the shortage of meteorological stations in Oasis regions.