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All the water vapor of atmosphere is contained in a column of the atmosphere that is capable of precipitation and it is from the ground to the final of water vapor called perceptible water. This element influenced by topography and height. The purpose of this study is survey about impact of local and spatial factors on distribution of perceptible water maximums in Iran.For this reason, pressure data, especially moisture, orbital and meridional components extracted from NCEP/NCAR and analysis. Correlation and regression methods were used in this study. In order to better survey about perceptible water gradient changes and gradient changes of maximum of perceptible water has been calculated. Results showed that among the spatial factors, height has greatest impact on the spatial distribution of the maximum of perceptible water. Unlike many scientists who believe that by increasing the latitude perceptible water reduced, this rule is less In Iran atmosphere. However, most of the gradient changes of perceptible water occurred in some parts of the Zagros highlands, West and South West. The results of cycle analysis showed that the maximums of perceptible water in Iran have short term cycles between 2 to 4 years.

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Survey of advection of cold waves in Iran is the main aim of this study. In this regard, 45 synoptic stations were employed and studied. In order to investigate the thermal advection of cold waves, 1000, 850, 700 and 500 hp levels were reviewed and analyzed. Results indicated that cold waves in Iran most affected thermal advection caused by Tibet- Siberia, Siberias integrated Turkmenistan high-pressure, High pressure belt of Siberia - East Europe High pressure, Siberian high-pressure multi-core pattern and High-pressure belt of East of Caspian Sea integrated Black Sea High pressure. In the meantime, thermal advection of Siberian high pressure has been more impressive than other patterns. This system moved towards lower latitudes by anti-cyclone moving, So the cold weather of northern latitudes loss in lower latitudes North East of Iran, North West and Central parts of Iran. However, when Siberian high pressure combined with other patterns, its role in the advection of cold air have been considerable