3. Results and discussion Aridity maps were prepared using De Martonne Aridity Index, Thornthwaite Precipitation Effectiveness Index, Thornthwaite Wetness Index, UNESCO Aridity Index and of Erinc aridity. These indices showed that most of the southern parts of the country lie between arid and hyperarid zones, while the northern parts lie between semiarid and very humid zones (Fig-3). The analysis shows that the climate of the northern parts is more variable than the southern parts. The reason for the climate variability in the northern parts is that this region receives precipitation in summer due to monsoon systems (July to September) and in winter due to western disturbances (December to March). The southern parts of the country receive the most rainfall in the monsoon season, while there is little rainfall in winter. These monsoon rains alleviate moisture stress to some extent, but due to the low altitude, increased evapotranspiration, and daytime temperature, the dry climate exists year-round. Therefore, agricultural activity is not dependent on rainfall and adequate irrigation in the form of canals, rivers and tube wells is required. However, monsoon rains bring relief to overcome moisture stress to some extent. However, it becomes difficult for agriculture to survive in this climate. The total mean annual temperature and evapotranspiration in the south of the country are much higher than those in the north. Whereas the amount of rainfall is very low in the southern parts compared to the northern parts of the country. For this reason, the gap between evapotranspiration and precipitation causes dryness in the region, i.e. the greater the difference between these two, the more arid a region will be. Climate of the Ar...... middle of sheet......1: The climate of North America According to the new classification.Geogr.Rev.21 (4), 633-55.15. Thornthwaite, C.W. 1948: An approach towards the rational classification of climate Geogr.Rev.38:55-64.16. United Nations Convention to Combat Desertification, 2006: The Consequences of Desertification, Factsheet 3. (available at http://www.unccd.int/publicinfo/factsheets/showFS.php?number=3)17. United Nations Environment Programme, 1994: Earth Summit Convention on Desertification, United Nations Conference on Environment and Development, Rio de Janeiro, Brazil, 3-14 June 1992, Report DPI/SD/1576, Nations Unite, New York.18. United Nations Environment Programme, 1997: World Atlas of Desertification, 2 ed. United Nations Environment Programme, Nairobi.19. UNESCO, 1979. Definition of aridity (UN documents) United Nations Educational, Scientific and Cultural Organization, New York.