WMO WORKSHOP ON CLIMATE MONITORING INCLUDING THE IMPLEMENTATION OF CLIMATE WATCH SYSTEMS

FOR ARAB COUNTRIES IN WEST ASIA,AMMAN, JORDAN, 27-29 MAY 2013

Dust storm variability over EGYPT By

Fathy M ELashmawyEgyptian Meteorological Authority

Contents 1-Definitions of dust weather .2- Pressure systems of dust storm .3- Condition of occurrences of dust storm .Surface condition ,Meteorological conditions .4- Onset of dust storm .( How to predict of dust storm? )

5- Variation and trend monthly data dust storm with climate parameter .

dust storm .by analysis dust storm data and observation data synop and meters .

6- Concentration of dust emission.

Definitions of dust weather

Strong wind and

turbulent wind <1 kmAn ensemble of particles

of dust energetically liftedto great heights by a strong

and turbulent wind

Sand ,dust storm

Area of turbulence Bad weather

< 200 mstrong winds in the ground an aggressive manner

severe Sand ,dust storm in out breaks

Moderate wind1-10kmDust raised by the wind tomoderate heights aboveground

Rising sand,Plowing sand

Weak wind < 10 kmDust raised by the wind toa small height above theground

Dust haze ,floating dust

Weather conditions

Horizontal visibility

Characteristics Categories

Favorable condition of occurrence of dust storm

Surface condition1- Low soil moisture2- Smooth surfaces3- Fine, loose soil particles4- Sustained high wind at low-levelMeteorological conditions1- Thermally unstable atmospheric stratificationFrontal systems2- Down-drafts from meso-scale convective systems, 3- Boundary layer turbulence4- Dry soil or sand layer

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Dust storm Pressure systems affect on Egypt

1- Frontal depressions (prefrontal, postfrontal ) Mediterranean cuprous low.

2- Desert depression system3- Red sea trough system4- Mesoscale systems

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Mechanism of dust storm• ANALYSIS THE CAUSES OF SAND-DUST STORMS• Researchers shows that the formation of sand-dust

storms is determined by the following three basic conditions:

• 1) Strong wind not sufficient to cause sand or dust emission from surface but Wind is the motive power of the formation of sand-dust storms.

• 2) Sand composition on land surface is the material foundation.

• 3)unstable atmospheric condition is the local heating power condition. Most sand-dust storms took place

• during the period from afternoon to evening

Mechanism of dust storm

More heating in surface for convective cloud and dust

drifting

Meso-scale system Strong wind with turbulent area with more heating

Unstable weather in east Egypt and west soudia Arabia

Red sea trough From surface to upper trough in east medit

Rise in temperature

decrease in RH ,slpstrong wind ,turbulent area

with down draft

Desert depressionTurbulent area to upper level Extend to 700hpa

Increase in RH –strong wind – fall in temperature

Frontal depression ( pre- past frontal ) Turbulent area to upper level

Analysis Pressure systems MSL of dust ,sand storm affect Egypt

Wall of dust near Cairo

Frontal depression 35% Cyprus low

Meso scale system 10% 23/06/2012

Desert depression 32% 17/04/2007

Red sea trough 15% 15 /07/2010

By analysis the observation data of SDS and in metar and

synop meteorological data in some station different location

C - Mean synoptic patterns of dust stormin south and east Egypt in Autumn red sea trough

Extend to north red sea

A- Mean synoptic patterns of dust stormin over Egypt in winter cyprus low

B- Mean synoptic patterns of dust stormover Egypt in spring desert depression

D - Mean synoptic patterns of dust stormin south Egypt in summer high pressure

Annual variability of dust storm over Cairo ( 1968-2010)

Annual time series of DSF on Cairo ( 1968-2010)

0

2

4

6

8

10

12

14

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

years

DSF

Monthly variability of SDS on Cairo

• From DEC to MAY dust season More frequency in marc h 39 days and may 38 days Tatal days 162 SDS

interannual variability SDS of cairo 1968-2010

13

16

28

39

14

4

01

4

23

38

0

5

10

15

20

25

30

35

40

45

dec jan feb mar apr may jun jule aug sep Oct nov TOTAL

month

numbe

r of d

ays

Monthly dust storm frequency on Aswan 1968-2010more occurances in April 66 days and March after May

Monthly dust storm frequency on marsa matrouth 1968- 2010more occurrences in April 60 days and March 53 days after May

23days

monthaly dust storm frequency on marsa matrouth 196 8-2010

3635

53

60

23

6 7

3

12

29

20

37

0

10

20

30

40

50

60

70

jan feb mar apr may jun jul aug sep oct nov dec total

month

no of S

DS day

s

Monthly dust storm frequency on nozha 1968-2010more occurrences in march31 days and dec 15 days

interannual variability of DSF on alexandria 1968-2 010

0

5

10

15

20

25

30

35

dec jan feb mar apr may jun jul aug sep oct nov

month

DSF

Annual DSF on Alexandria( 1968-2010

annual time series of dust storm on alexanderia (19 68-2010)

0

1

2

3

4

5

6

7

8

9

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

years

DSF

Time series of dw,rs,DH and sds in cairo1968-2010DW,RS ,SDSand DH in cairo 1968-2010

0

50

100

150

200

250

300

350

400

450

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

years

num

ber o

f day

sdw

,rs,h

z

0

2

4

6

8

10

12

14

HAZE rs DW sds

sds

days

Annual Dw days ,rainfall Cairo 1968-2010-ve correlation

0

20

40

60

80

100

120

140

160

180

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

0

50

100

150

200

250

300

350

400

450

PREC

DW

Mean Roots of Dust activity• In North Africa the maximum dust transport occurs in

summer when large quantities of dust are carried across the Mediterranean to Europe and the Middle East [Moulin et al., 1998] and across the Atlantic to the Caribbean in spring

• There is also considerable transport in the winter months when large quantities of dust are carried into South America dust activity shifts with the season In North Africa the winter dust activity is greatest in the low latitudes; as the year progresses, dust activity moves to the higher latitudes. In the Middle East,

• Activity peaks in the late spring and summer and is at a minimum in the winter.

Onset of dust , sand storm How to forecast with dust storm ?

• By analysis the observation data synop and Metar of dust storm occurs from( dec to may )

• before dust storm occurs Heat wave. • continue dropping in slp• decrease in relative humidity below normal's (

with strong and southerly wind.• Strong sw wind or SE and dry .

Examples of dust storm systems hit Egypt

18/4/201222/01/2004

Prefrontal systems Postfrontal system

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Spatial and Temporal distribution of SDS on EGYPT

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Annual variability of sds and rainfall in Marsa Matrouth (1968-2010 )

Annual sds,rain fall in marsa matrouth (1968-2010)

0

50

100

150

200

250

300

350

400

450

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

years

days

of d

ust s

torm

,

0

5

10

15

20

25

30

35

PREC sds

Poly. (sds) Poly. (PREC)

Rain

fall m

m

Time series dw( spring ) and air temp winter Seasonal variability

dw in spring and mean temp in perior bwinter nega tive correlation -0.236

0

5

10

15

20

25

30

35

40

45

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

years

day

num

ber

12.0

13.0

14.0

15.0

16.0

17.0

18.0

dw spring mTspring

Poly. (mTspring ) Poly. (dw spring)

Me

an

tem

p

Dw,MT Aswan MAM negative correlation -0.207

time series in dw ,MT in 414 aswan ( 1968-2010)

0

10

20

30

40

50

60

70

80

90

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

years

dw

24.5

25

25.5

26

26.5

27

27.5

28

28.5

29

29.5

DW MT Poly. (DW) Poly. (MT)

tem

p de

g c

Dust weather accumulated number of days (

DZ+rs+sds

24 26 28 30 32 34

24

26

28

30

32

34

020406080100120140160180200220240260280

Annual distribution of dust weather in egypt

Red sea

Mediterrnean sea

Thank you

Month with more frequency SDS ( march 1970,1971 ) 6 days in Marsa Matrouth more warming in the source

of dust emissions

high

In upper level 100mp high pressure in the

source of dust emissions

• A positive correlation exists between the quantity of dust in the air, and the wind velocity.

• Whereas, a negative correlation exists between dust amount and the particles’ size. Precipitation and/or vegetation coverage may reduce

• considerably the amount of dust in the air for a given wind velocity and/or particles’ size

How calculate the concentration of dust ?

• To quantify the dust, we converted the visibility to PM10 (small particles with a diameter ≤10 × 10-6 m).

• in which the visibility was ≤5000 m. The relation which yielded the highest correlation between the visibility and PM10 concentration

• (R = 0.72, p = 0.005), is:• y = 16.009x + 936.9• R2 = 0.0116• where y is the PM10 concentration, in µg m−3, and• x is the visibility, in 100 m units.

pm10,vismeters cairo 18/04/2012( 06-20)hr

y = 16.009x + 936.9R2 = 0.0116

0

500

1000

1500

2000

2500

3000

40 10 8 20 20 20 12 8 10 10 15 20 40 60 60

visibility meter

pm10

mg/

cm3

pm10mg/cm3

hours

Linear (pm10mg/cm3)

y = 16.009x + 936.9R2 = 0.0116

Result• The monthly data indicate that the dust season starts in October and ends in May, with a

maximum in March. And April • than 82% of the total annual dust is accumulated between December and May, the ‘high

dust season’ from The annual totals• vary as much as an order of magnitude from year to year.• The synoptic system that produces the majority of the dust over the northern Egypt is the

Cyprus Low, and desert cyclone contributing• 2/3 of both the total yearly dust yield and of the number of dust observations. This

suggests that a positive relationship• exists between the dust in the Negev and rainfall in north Israel, both of which are

generated by Cyprus Lows. Indeed,• a significant (at 0.05 level) correlation of +0.30 was found between the two. Correlation

maps evidence that in dustrich• years the cyclonic activity over the Mediterranean is abnormally high and in poor-dust

years it is low. A highly• significant negative correlation ( -0.23 to −0.56) was found between the dust yield and the

intensity of the North Atlantic oscillation• (NAO), which modulates the cyclonic activity over Europe and the northern

Mediterranean. This may also imply that periods in which more dust accumulated as loess in the northern Egypt may indicate the existence of negative NAO

• phase, and concurrently, warmer conditions over the Sahara, colder conditions over Europe and enhanced rainfall over the Mediterranean Basin