CHAPTER 1.
GENERAL INFORMATION
1.1 GEOGRAPHICAL ENVIRONMENT
Geography
The Islamic Republic of Iran lies in the
western part of the Iranian plateau about north of eastern hemisphere and the
south-west of Asia, and is located approximately between 46°E and 62°E, and
26°N and 38°N. Its neighbours consist of
Azerbaijan, Turkmenistan and Armenia in
the north, which are around Caspian Sea, Afghanistan and Pakistan in the east
and Turkey and Iraq in the west. The sea frontiers of the Persian Gulf and Oman
Sea in the south related this country to the height seas and southern
neighbouring countries of the Persian Gulf.
It has an area of about 1,648,195 km² and
over half of that is mountainous. The main features of the topography can be
summarized as a great plateau, between two mountain ranges. In the north, the
Alborz Mountains have long east-west ranges of more than 2 km height; these
reach more than 5 km height in some places. In the west and southwest, the
Zagros Mountains extend over a very long distance. Most of the area is over
1800 m, much of it is over 3000 m and many summits exceed 3600 m. The great
plateau, rising 1 km above sea level, occupies most of the country. Some parts,
such as the Dasht-e-Lut and Seistan, are only about 500 m above the sea level.
South of the Caspian Sea, there are some narrow lands of about 20 m below the
sea level.
The principal language is Farsi (Persian),
spoken by about 50% of the population. Turkish-speaking Azerbaijanis form about
27% of the population, and Kurds, Arabs, Balochis and Turkomans form less than
25%.
The great majority of Persians and
Azerbaijanis are Shi’i Muslims, while the other ethnic groups are mainly Sunni
Muslims. There are also small minorities of Christians (mainly Armenians), Jews
and Zoroastrians.
The population is 58.1 million as of December
1997.
Climate
The country is mainly arid or semi-arid.
Except the northern coastal areas, the climate is extremely continental. In
summer hot and dry weather prevails generally and in winter very cold weather
is usual, in particular in inland areas.
The climate of the country can be divided
into three categories: warm, temperate, rainy with dry summer in a narrow strip
in the north; dry, hot desert in the central plateau; dry, hot steppe covering
the rest of the country.
Apart from the coastal areas, the temperature
in Iran is extremely continental. The annual range of temperature difference is
great, from 22°C to 26°C. Winter cold, especially in the north in which the
Elburz Mountains exist. The January mean temperature at Mashhad is 2°C and the
minimum is –25°C. On the plateau it is less cold than in the Elburz Mountains.
In summer hot weather generally prevails, in particular in the low land area
and enclosed valleys such as those of Khuzestan and Luristan where the daily
maximum often exceed 44°C.
Summer temperatures of more than 55°C have
been recorded. On the plateau the low humidity makes the heat bearable. In the
higher places the weather is generally mild and pleasant. At the coasts, where
the daily range of temperature is not so great as much inland, the weather is
very unpleasant due to the excess of moisture and increased heat.
Since Iran is situated at a considerable
height above sea level, the humidity is generally low except for the coastal
regions. In Bushehr, on the Persian Gulf, the mean relative humidity in the dry
season is about 60% while in Kerman, which is far inland, it sometimes is as
low as 8%. Therefore the summer weather in the Gulf area is very sultry.
The rainy period in most of the country is from
November to May. The average annual rainfall is about 240 mm. Maximum amounts
fall on the Elburz and Zagros slopes facing north and west respectively, which
the mean annual rainfall is more than 1200 mm. Going inland, the ranges’ of
precipitation decreases to less than 100 or 50 mm annually. The amounts vary
considerably with topography. In the northern and western mountains the annual
mean precipitation is more than 480 mm; snow forms most precipitation. The
plateau has most of its rainfall in spring, while on the western and southern
coasts most of the rain falls in winter. In the Caspian coast, where the rain
falls earlier, the rainfall is maximal in autumn. In the dry period between May
and October, rain is rare in most of the country.
Top
CHAPTER 2.
METEOROLOGICAL AND HYDROLOGICAL SERVICES
2.1
STRUCTURE
2.1.1 Headquarters
Government
Department Ministry of Roads and
Transportation
Service........................ Islamic Republic
of Iran Meteorological Organization (IRIMO)
Address....................... P.O.Box
13185-461, Tehran
Telephone.................... (98-21) 600 4041-2
(Direct);
(98-21)
600 4026-8 Ext. 333, 331
Telefax........................ (98-21) 646
9044; 646 9050; 600 0417
Telex.......................... 21 36 25 METO
IR; 22 42 44 METI IR
Cable.......................... HAVA SHENASI
E-mail......................... noorian@dci.iran.com
Permanent
Representative Dr Ali-Mohammad NOORIAN
(Since 6
September 1994)
Vice-Minister
of Roads and Transportation
President
of IRIMO
Second
Vice-President of WMO
2.1.2 Organization
The
meteorological service was assigned to an independent organization in 1958,
which has evolved into the present Islamic Republic of Iran Meteorological
Organization (IRIMO). IRIMO is composed of eight divisions namely:
i Research and Scientific Investigation;
i Administration;
i Technical
Services (laboratories, technical supervision, telecommunication services,
electronic and engineering services);
i Network (climatological observation,
agricultural observation);
i Operation (forecasting, synoptic observation,
aeronautical control, marine meteorology, agrometeorological);
i Information and Data-processing
(data-processing, data bank, publication);
i Training Department (training of Class I, II,
III and IV meteorological personnel); and
i A Bureau in charge of the international
meteorological affairs.
The
country has been divided into 28 provinces, in each of which, IRIMO has
established meteorological offices.
2.1.3 Staff and budget
Staff
The
IRIMO’s operational staff professional, sub-professional, clerical and support
personnel as of December 1997 totalled 1,613 persons.
Budget
2.1.4 General fund contribution to WMO
(As of 30 November 1998)
|
Contributions paid (CHF)
|
Current arrears (CHF)
|
|
1998
|
Total paid
|
1996 - 1997
|
1998
|
Total
|
|
306,067.00
|
0.00
|
376,939.00
|
306,067.00
|
683,006.00
|
Top
CHAPTER 3.
TECHNICAL AND SCIENTIFIC PROGRAMMES
3.1
OBSERVATION
3.1.1 Basic observing networks
The total
number of rainfall stations of IRIMO is 2420. In addition, the Ministry of
Energy has its network of precipitation stations consisting of approximately
1619 stations.
The
agrometeorological stations are equipped as climatological stations. In addition,
they include measurements of crop growth and soil-moisture conditions.
Soil-moisture is measured by gravimetric methods for four to five sets of
samples of 10 cm each down to the depth of 70 cm. These measurements are
performed approximately 20 times a year, usually before and after irrigation
and after rainfall events (except during wintertime).
Most
instruments are calibrated at IRIMO and the different types of stations are
standardized according to international recommendations. Both recording and
ordinary raingauges are used at the synoptic weather stations. They are not
equipped with wind shields and data are not corrected for errors due to high
wind speeds, etc. The rainfall stations are equipped with ordinary and Data
loggers raingauges.
Twelve
automatic weather stations are in operation and 10 of these were placed at each
one of the regional centres. Data collected are transmitted directly to a
microcomputer at the regional centres.
3.1.2 Space based sub-system
A
meteorological satellite receiving equipment was installed at IRIMO in February
1992. This system receives METEOSAT low- and high-resolution images and NOAA
high- resolution images. We upgraded the system in 1998 and now we have MDD and
DCP RS receiver system. A time-lapse animation consisting of up to 60 pictures
can be produced and a user can configure up to four separate animations. The
system is used half-hourly to aid forecasters. Since it is a new system, much
effort is being given to train local forecasters for its most efficient use.
Network of meteorological observation
(As of
July 1998)
|
Type of station
|
No. of
station
|
Remarks
|
|
Synoptic
i RBSN-SYNOP
i RBSN-CLIMAT
i
RBSN-TEMP
|
155
74
74
9
|
The
network gives an average density of a synoptic station per 12,200 km².
|
|
i Radiosonde
i Pilot balloon
i Two obs. daily
i One
obs. daily
|
13
11
2
1
12
|
|
|
|
1
|
One 3 cm
analogue radar in Tehran. Rainfall estimation is not possible.
|
|
AWS
|
12
|
|
|
Agrometeorology
sta.
|
22
|
|
|
Climatology
station
|
261
|
|
|
Rainfall
station
|
2420
|
|
|
Aeronautical
station
|
47
|
(Aeronautical
Station+Synoptic Station lies in Airport)
|
CHAPTER 1.
GENERAL INFORMATION
WMO/VCP, RB AND BILATERAL PROJECTS