The statistical information appeared in this chapter are delivered in three sections: Geographical characteristics and administrative divisions, Climate, and Environment.

1. Geographical characteristics and adminis- trative divisions

Iran comprises a land area of over 1.6 million square kilometres. It lies down the northern temperate zone, between latitudes 25º 00' north and 39º 47' north and between longitudes 44º 02' east and 63º 20' east. The land’s average height is over 1200 metres. The lowest place, located in Chaleh-loot is only 56 metres high, while the highest point, Damavand peak in Alborz mountains, rises as high as 5610 metres. At some points of the southern coastal strip of the Caspian Sea, land height is 28 metres lower than the open seas.

Iran is bounded by Turkmenistan, Caspian Sea, Azerbaijan, and Armenia on the north, Afghanistan and Pakistan on the east, Oman Sea and Persian Gulf on the south, and Iraq and Turkey on the west.

Administratively the country is divided into Ostans, Ostans into Shahrestans, and Shahrestans into Dehestans.

2. Climate

The country generally features three climatic zones;

1. Arid/semi-arid regions of the interior and far south characterized by long, warm and dry periods, lasting some years over 7 months. The annual precipitation in such regions varies between 30 to 250 mm.

2. Mountainous extensions, which are sub-divided into cold and moderate mountainous regions.

2.1. Cold mountainous regions: about 40000 sq km of the total consists of major highlands, including Alborz and Zagross mountain ranges, as well as Sahand and Sabalan high peaks. The annual precipitation in these regions exceeds 500 mm.

2.2. Moderate mountainous regions: some 300000 sq km of the country enjoys moderate mountainous climate, where the annual precipitation varies from 250 to 600 mm.

3. Caspian region, which is a narrow strip with a limited extension, trapped between the Caspian Sea and Alborz mountains with as much as 600 to 2000 mm precipitation per annum.

Measurement of climatic characteristics, which dates back to 1320, is currently performed by the National Meteorological Organization at its numerous synoptic stations scattered around the country. The data in this chapter, however, are only from those located in Ostan (provincial) centres. They include temperature, precipitation, relative humidity, the number of frosty days, hours of bright sunshine and speed of wind.

Ostans of Tehran and Hamadan have got more than one synoptic station and the data appeared here are from those located in airports.

Also, Sari synoptic station became operational in 1379.

3. Environment

Environment statistics have been reflected in the Iranian statistical yearbook since 1368. The data in this chapter are the only available related information and are on the natural resources and heritages covered by the Environment Protection Organization.

Definitions and concepts

Roosta (hamlet): a type of Abadi (village) defined in chapter 2.

Dehestan (rural agglomeration): the smallest unit among administrative divisions with a specific geographical boundary, comprised of a number of neighbouring Roostas and their adjacent places and fields, homogeneous in environment, economic and social conditions that allow for providing public services and planning within a single system.

Shahr (city/town): an area with a legal boundary, located within the geographical boundary of a certain Bakhsh and having a city hall of its own.

Bakhsh (county): an administrative division with a specific geographical boundary, including a number of neighbouring Dehestans and their adjacent fields, places, Roostas, and possibly, Shahrs, which are similar in natural, social, cultural, economic and political aspects.

Shahrestan (subprovince): an administrative division with a certain geographical boundary, formed from joining of a few neighbouring Bakhshes which enjoy homogeneous natural, social, economic, political and cultural conditions.

Synoptic stations (simultaneous meteorological reporting stations): the stations at which various climatic features including dry and humid temperatures, amount and type of cloud, amount of precipitation, type of climatic phenomenon, direction and speed of wind, amount of evaporation, air pressure, and hours of bright sunshine are according to certain instructions at certain hours measured and communicated to meteorological centers across the globe after being registered.

Absolute minimun: the lowest temperature during a certain period (24 hours, one month, one year, or a few years).

Absolute maximum: the highest temperature during a certain period (24 hours, one month, one year, or a few years).

Relative humidity: the amount of humid air in a volume unit of air.

Water basin: an area of a region in which the flowing waters from regional precipitation converge naturally to a certain point, known as the concentration point; If the point is located inside the basin, the basin is a closed one (eg Orumiyeh Lake), but if the point is located at the end of the basin, then there is an open basin. Every given point in a river is considered the concentration point for the basin just above it.

Coefficient of overland flow: the ratio of the volume of water flowed in a given hydrometric station to the volume of the precipitation of the basin stretching to the station.

Volume of overland flow: To estimate the volume of overland flow of each of the country’s main basins, a total of 42 rivers have been selected to indicate and represent the overall overland flow. The total volume of overland flow of the group exceeds 60 percent of the country’s grand total. To reach the volume of any individual flow, a proper coefficient is applied to the total volume.

National parks: certain areas of the country’s nature representing top natural resources, which might embrace woods, pastures, natural groves, jungle lands, plains, or mountainous regions. Such areas are protected in order to preserve the natural conditions and blessings and to ease reproduction of domestic wildlife and growth of regional plantaion.

Wildlife habitats: protected areas of the country involving woods, pastures, plains and mountainous regions with distinguished natural habitats and proper environmental conditions for the wildlife.

Nature reserves: protected areas of the country’s nature, including jungles, pastures, plains, or mountainous regions which are habitat for important or rare species of wildlife and/or plantation.

National natural heritages: specific and rare species of plants or animals, unique picturesque settings, specific natural forms of the earth, as well as very old trees, which are protected to be safe and preserved.