Quick Look

Climatology
The summer pressure field closed to the surface is marked by a low pressure rfegion which extends from the Tibetean Plateau to the Arabian Peninsula. This is the same low pressure field, which is also responsible for the formation of the monsoon (figure 2a). In higher altitudes over the Arabian Peninsula this low pressure is gradually replaced by a high pressure region, which is an expression of downward air motion (subsidence). The subsidence is an expression of a global climate feature. There exist two high-pressure belts one in the northern and one in the southern hemisphere, where air is forced to sink and where therefore cloud formation is low and deserts prevail. The high pressure over the Arabian Peninsula is part of this feature. The air that is forced down over the dessert has to flow out of the Peninsula, which leads to the upper atmosphere not winds which are common in Dhofar at pressure levels lower than 900mbar.
This high pressure is responsible for the upper air north winds in Dhofar.

The winter pressure fields were included to this page for matters of completeness.

The summer surface pressure data (for example August in figure 1) show a region of higher pressure around the upwelling region. However it can be seen that this local high is a very small feature as compared to the overall pattern.

Data
To create the pictures for this page we used two different datasets: NCEP reanalysis and COADS. More information on the datasets can be found in the section “dataset information” by klicking on the name of the dataset.

Surface Pressure

figure 1: climatology of August Sea Surface Pressure over the Arabian Sea (in mbar)

Pressure level 1000mb

figure 2a: climatology of summer (JJA) geopotential height at 1000mb level over the Arabian Sea and the Arabian Peninsula (in m)

figure 2b: climatology of summer (DJF) geopotential height at 1000mb level over the Arabian Sea and the Arabian Peninsula (in m)

Pressure level 850mb

figure 3a: climatology of summer (JJA) geopotential height at 500mb level over the Arabian Sea and the Arabian Peninsula (in m)

figure 3a: climatology of summer (DJF) geopotential height at 850mb level over the Arabian Sea and the Arabian Peninsula (in m)

Pressure level 500mb

figure 4a: climatology of summer (JJA) geopotential height at 500mb level over the Arabian Sea and the Arabian Peninsula (in m)

figure 4a: climatology of summer (DJF) geopotential height at 500mb level over the Arabian Sea and the Arabian Peninsula (in m)