عنوان مقاله [English]
The modern meteorological studies began with the invention of hygrometer and anemometer by Da Vinci in 1500, and reached a more complete form by invention of thermometer in 1593 by Galileo. Raining in Italy in the year 1639 was measured by Castelli’s rain gauge. In 1653, Ferdinand formed a network of observation stations. The longest climatological observations began since 1664 in Paris (Linker, 1992). Climatological observations continued to make progress along with technological advancement. Today, international meteorological networks cover all around the world; climatic elements are observed several times a day and transmitted to national and international meteorological organizations and analyzed there, and relevant statistics and maps are published every year.
Frozen precipitation, especially snow, has received less attention in our country, and comprehensive works on this phenomenon are infrequent. Difficulties of the task and study in mountainous areas which are the main extent for frozen precipitation have constrained research activities in this regard.
Snow is one of the important factors in environment and, as a type of precipitation, is a suitable reserve for storing water over long periods (Suruk, 1993). Slow hydrological reaction, avalanche, special micro-climate, intense reflection of solar energy and other factors have made snow as one of the most important and interesting climatic phenomena.