Chapter 6: Dust storms

Question 1

Dust storm in the Middle East and south-west Asia is a natural hazard and the ………………………. plain has been recognized as the main dust source in this area

Answer 1

Tigris-Euphrates alluvial

Question 2

Dust storms in the region can be grouped into two main categories, i.e.,

Answer 2

• the Shamal dust storms and
• the frontal dust storms.

Question 3

frequency of patterns

Answer 3

• For 68% of the Shamal dust storms, a high pressure system is situated between 0oE to 30oE and 27oN to 45oN, and a low pressure system between 50oE to 70oE and 23oN to 43oN.
• For 86% of the frontal dust storms, a high is located between 51oE to 67oE and 18oN to 33oN and a low between 28oE to 48oE and 32oN to 43oN.

Question 4

Three main patterns for Shamal dust storms are identified, which represent about

Answer 4

60% of the Shamal dust storms

Question 5

Three main patterns for Shamal dust storms are identified, which represent about 60% of the Shamal dust storms. This analysis confirms that the Shamal is related to

Answer 5

the anticyclones located over northern Africa to Eastern Europe and the monsoon trough over Iraq, southern Iran, Pakistan and the Indian Subcontinent.

Question 6

This analysis confirms that the Shamal is related to the anticyclones located over northern Africa to Eastern Europe and the monsoon trough over Iraq, southern Iran, Pakistan and the Indian Subcontinent. The analysis also shows that the main dust sink for the frontal dust storms in Tigris and Euphrates alluvial plain extends from

Answer 6

center of Iraq to west and center of Iran and, in most severe cases, to northern Iran and the southern coast of the Caspian Sea.

Question 7

Mineral dust aerosol is involved in many important pro- cesses in Earth’s climate system including

Answer 7

• radiative forcing,
• nutrient transport,
• land-use change, and
• ecosystem health

Question 8

Dust storms and suspended dust pose serious environmental pro- blems in

Answer 8

south-west Asia and natural hazards in the Middle East region.

Question 9

Major dust storms occur over the Middle East region nearly every

Answer 9

spring and summer and cause destructive effects in some countries like Iraq, Saudi Arabia and Iran.

Question 10

Model simulations suggest that the dust emission from this region contributes to about ………….. of the global total emission.

Answer 10

20%

Question 11

The Tigris-Euphrates alluvial plain has been recognized as

Answer 11

he main dust source in the Middle East.

Question 12

he Tigris-Euphrates alluvial plain has been recognized as the main dust source in the Middle East. The dust originating from this area can be transported over

Answer 12

large distances because the dust particles from this area mainly consist of fine sedi- ments from the Tigris and Euphrates rivers

Question 13

The Tigris-Euphrates alluvial plain has been recognized as the main dust source in the Middle East. The dust originating from this area can be transported over large distances because the dust particles from this area mainly consist of fine sedi- ments from the Tigris and Euphrates rivers. Therefore, the dust storms from the Middle East also have important impacts on

Answer 13

the neighboring countries like Iran.

Question 14

The dust originating from this area can be transported over large distances because the dust particles from this area mainly consist of fine sedi- ments from the Tigris and Euphrates rivers. Therefore, the dust storms from the Middle East also have important impacts on the neighboring countries like Iran. The dust activities have intensified in the

Answer 14

Mesopotamian area in recent years, partly due to the development of the dam construction projects on Tigris and Euphrates rivers.

Question 15

Construction of new dams decrease

Answer 15

the humidity and water content of soil in the downstream areas, which consequently lessen the threshold friction velocity of the soil and its resistance against wind erosion.

Question 16

The seasonal variation of dust activity in the Middle East is

Answer 16

complex and differs for different regions

Question 17

The seasonal variation of dust activity in the Middle East is complex and differs for different regions. Over much of the Middle East, dust is active

Answer 17

all year long, but it decreases in the winter months.

Question 18

Over much of the Middle East, dust is active all year long, but it decreases in the winter months. Dust activity increases in

Answer 18

March and April

Question 19

Over much of the Middle East, dust is active all year long, but it decreases in the winter months. Dust activity increases in March and April, peaks in

Answer 19

June and July and weakens in September

Question 20

The MODIS satellite images between 2003 and 2011 show that nearly

Answer 20

60 dust storms occurred in the Middle East, which are reported as natural hazards in the area by NASA

Question 21

The MODIS satellite images between 2003 and 2011 show that nearly 60 dust storms occurred in the Middle East, which are reported as natural hazards in the area by NASA. Amongst these, 12 severe dust storms were considered for synoptic analysis of the dust storms in this area. The distinguished feature of these selected dust storms is that,

Answer 21

their dust plumes were spread and covered the western to central part of Iran.

Question 22

The MODIS satellite images between 2003 and 2011 show that nearly 60 dust storms occurred in the Middle East, which are reported as natural hazards in the area by NASA.

The rest of 48 dust storms were just spread over

Answer 22

Iraq and a smaller part of Iran.

In four of the selected cases, the dust plumes reached the north-eastern to eastern part of Iran and affected the Caspian Sea region.

Question 23

The analysis of the MODIS satellite images shows that the dust storms from the Tigris- Euphrates alluvial plain may affect

Answer 23

more than 10 countries in the Middle East.

Question 24

The Middle East, largely made up of the

Answer 24

Arabian Plateau and the Tigris-Euphrates Basin, is an area of active wind erosion.

Question 25

The Arabian Plateau

Answer 25

slopes down from the southwest high terrains (1,500-3,000 m) bordering the Red Sea towards the northeast flat lands (50-200 m) adjacent to the Persian Gulf.

Question 26

Arabian Peninsula

Two dust areas have been identified

Answer 26

The first covers the Tigris-Euphrates River alluvial plain in Iraq and Kuwait, the low-lying flat lands in the east of the peninsula along the Persian Gulf and the Ad Dahna and the Rubal Khali deserts (Shao, 2008). The alluvial plains have the highest frequency of dust storms in the Middle East (Safar, 1980).

The second dust area is found off the Oman coast, and the number of daily dust-storms in this area is rather low and thus is eliminated from this study.

Question 27

In this paper, the land surface is divided into

Answer 27

non erodible areas which are not prone for dust emission, and potential dust source regions which can be used for dust emission in numerical models.

The potential dust source regions are defined on the basis of remotely sensed leaf area index (LAI), topography (H) and surface type (S).

Question 28

It should be mentioned that alluvial plains as a source of

Answer 28

fine sediment for dust are usually placed above the sea level but not very high to face mountains

Question 29

Therefore, as the most part of the present study area located in Iran and Arabian plateau with high altitude, critical height topography of

Answer 29

500 m, 700 m and 900 m were selected for this investigation, which cover most of the potential dust sources.

Question 30

The climate in the Middle East is mainly affected by four systems:

Answer 30

(a) The Siberian anticyclone in winter over central Asia;
(b) The Polar anticyclone in summer over east of Europe and Mediterranean Sea;
(c) The monsoon cyclones in summer over the India Subcontinent, south and southeast of Iran and southeast of Arabian peninsula;
(d) The depressions travelling from north of Africa and south and east of Mediterranean sea across the Middle East and southwest of Asia in the non- summer seasons (spring and winter).

Question 31

the two main kinds of synoptic scale dust storms in this region

Answer 31

Summer Shamal and frontal dust storms

Question 32

Summer Shamal and frontal dust storms are the two main kinds of synoptic scale dust storms in this region. Severe dust storms occur in

Answer 32

summer and associated with Summer Shamal (for simplicity called Shamal in this study).

Question 33

In non-summer season, ………….. most common type

Answer 33

frontal dust storm

Question 34

Summer Shamal

Shamal (means north in Arabic) dust storm occurs across

Answer 34

Iraq, Kuwait, western part of Khuzestan plain and some parts of Arabian Peninsula.

Question 35

Shamal (means north in Arabic) dust storm occurs across Iraq, Kuwait, western part of Khuzestan plain and some parts of Arabian Peninsula. It blows

Answer 35

almost daily during the summer months from June through September.

Question 36

The summer Shamal travels

Answer 36

across central and southern Iraq and picking up dust from Tigris and Euphrates rivers alluvial plain.

Question 37

The synoptic feature that creates the potential for the Shamal is a

Answer 37

zone of convergence between the subtropical ridge, extending into the northern Arabian Peninsula and Iraq from the Mediterranean Sea and Monsoon Trough across southern Iran and southern Arabian Peninsula.

Question 38

The synoptic feature that creates the potential for the Shamal is a zone of convergence between the subtropical ridge, extending into the northern Arabian Peninsula and Iraq from the Mediterranean Sea and Monsoon Trough across southern Iran and southern Arabian Peninsula. The zone of convergence is

Answer 38

caught bet- ween the pressure systems and Zagros Mountains of western Iran.

Question 39

The zone of convergence is caught bet- ween the pressure systems and Zagros Mountains of western Iran. It tends to force

Answer 39

an acceleration of the northerly low-level winds across southern Iraq, the western Khuzestan Plains of Iran, Kuwait, the northwestern Persian Gulf, and the north- eastern Arabian Peninsula.

Question 40

Frontal dust storms

Answer 40

are dynamic synoptic systems that mix the dust in the air and carry it for great distances in non- summer seasons.

Question 41

Frontal dust storms are dynamic synoptic systems that mix the dust in the air and carry it for great distances in non- summer seasons. The two main types of frontal dust storms in Tigris and Euphrates rivers alluvial plain are

Answer 41

prefrontal and postfrontal dust storm; each (has own local name) occurs at a specific time in the life-cycle of migratory low-pressure area with a frontal system.

Question 42

Prefrontal dust storms occur across

Answer 42

Jordan, Israel, the northern Arabian Peninsula, Iraq and western Khuzestan Plains of Iran, as low-pressure area move across the region.

Question 43

Prefrontal dust storms

how do the winds form

Answer 43

The polar jet stream (PJ) behind the front and the subtropical jet stream (STJ) in the front often converge into a single jet maximum that translate to the surface northeast of the upper-level maximum.

These prefrontal winds are known as Sharki in Iraq and Kaus in Saudi Arabia

Question 44

In Baghdad, the Sharki and Kaus winds cause

Answer 44

more than a third of all instances of blowing dust; easterly to southerly are the favored directions from October to April. Postfrontal dust storms are referred as a winter Shamal across most of Middle East. Locally, it is called Belat in southern Saudi Arabia.

Question 45

Postfrontal dust storms are referred as a winter Shamal across most of Middle East. Locally, it is called Belat (Middleton, 1986) in southern Saudi Arabia. Since a front is a

Answer 45

density current, vertical motions like in density current surges are also generated along the frontal zone. These horizontal and vertical vortices lift and suspend dust and sand particles.

Question 46

Shear lines are

Answer 46

another kind of frontal dust storm in Middle East, which is very frequent in winter and occur over west of Arabian Peninsula, the red sea and equatorial Africa.

Question 47

Shear lines are another kind of frontal dust storm in Middle East, which is very frequent in winter and occur over west of Arabian Peninsula, the red sea and equatorial Africa. This kind of dust storm rarely occurs in

Answer 47

Tigris and Euphrates River alluvial plain and cannot be a main type of dust storm in this area