عنوان مقاله [English]
نویسنده [English]چکیده [English]
In order to investigate and analyze the synoptic patterns in relation to heavy
summer rain happening in the northern areas of Khorasan Province during 2001-2002,
the earth surface pressure maps and the 500 mb ones were examined .
The most significant patterns that were in coordination with the real flood happening
were as follows:
High pressure of the Caspian Sea, the higher atmosphere level trough, Kavir plain
low pressure, combination of polar and subtropical jet stream. Out of 18 cases under
study, 44.4 % including 8 cases, were about high pressure of the Caspian Sea and
north flows over this sea, 27.7% including 5 cases, were concerned with higher
atmosphere level trough, 11.1% including 2 cases, were related to Kavir plain low
pressure, and 16.2% including 3 cases, were due to a combination of polar and
subtropical jet stream .
The patterns related to high pressure of the Caspian Sea and Kavir plain low
pressure have happened in the hottest summer days and higher atmosphere level
trough with a combination of polar and subtropical jet stream occurred in spring .