analysis of rainfall over saudi arabia

JKAU: Met., Env. & Arid Land Agric. Sci., Vol. 22, No. 2, pp: 59-78 (2011 A.D./1432 A.H.)

DOI: 10.4197/Met. 22-2.4

59

Analysis of Rainfall over Saudi Arabia

A. Mashat and H. Abdel Basset

Department of Meteorology, Faculty of Meteorology, Environment,

and Arid Land Agriculture, King Abdulaziz University,

Jeddah, Saudi Arabia

Abstract..In this study, rainfall over the Kingdom of Saudi Arabia

(KSA) is analyzed using data from available meteorological stations.

The analysis of these data shows that the highest amount of rainfall

occurs during the spring over the southwest, middle and east of KSA.

The second highest amount of rainfall occurs during winter over the

east and northeast of KSA. The season of the lowest amount of

rainfall over KSA is summer, when, except in the mountainous area in

the southwest region, the amount of rainfall is very small. While the

horizontal distribution pattern of rainfall during autumn is somewhat

similar to that during spring, the amount of rainfall in autumn is

smaller than that in spring. The most significant synoptic feature

appears in spring when the cold air associated with secondary

Mediterranean depressions meets the moist hot southerly air

associated with Red Sea trough over KSA.

1. Introduction

The amount of rainfall that falls over an area is an important factor in

assessing the amount of water available to meet the various demands of

agriculture, industry, and other human activities. Study of the distribution

of rainfall over time and space is therefore very important for the welfare

of a national economy. Many applications of rainfall data are enhanced

by knowledge of the actual distribution of rainfall over a specified area

rather than relying on simple summary statistics. In recent years, several

studies have been devoted to the interannual and decadal variability of

precipitation on regional, national and international scales. Different

methodological approaches have been used, such as temporal analysis of

60 A. Mashat and H. Abdel Basset

rainfall (Serrano, et al., 1999; De Luís, et al., 2000; Estrela, et al., 2000;

Agnese, et al., 2002; Turkes, et al., 1996), analysis of extreme events in

regional daily precipitation series (Brunetti, et al., 2002 and 2004), and

use of the standardized precipitation index (Delitala, et al., 2000; Lana, et

al., 2001; Bordi, et al., 2001; and Lloyd-Hughes and Saunders, 2002).

Several researchers have analyzed hydro-meteorological time series in

West Africa from Niger to Senegal (Carbonnel and Hubert, 1985 and

1994; Snijders, 1986; Hubert and Carbonnel, 1987; and Paturel, et al.,

1997). They pointed out the non stationarity of the series and suggested a

climatic change between 1965 and 1972, with the majority of the shifts

appearing between 1969 and 1970. Precipitation in the Great Plains of

the United States also changed significantly with an increase since the

late 1960s and the last two decades of the twentieth century being the

wettest of that century (Garbrecht and Rossel, 2000). A report from the

Office of Technology Assessment (1993) pointed out that the anticipated

intensification of the hydrological cycle would increase global rainfall by

7 to 15 % and evapotranspiration between 5 and 10%. An increase in

extreme events that will be disruptive to natural and human systems is

likely to occur (IPCC, 1995). However, whereas in certain areas an

increase of rainfall is expected, other areas will suffer from decreased

rainfall.

The aim of this study is to analyze the climatology of monthly and annual rainfall over the Kingdom of Saudi Arabia (KSA). The remainder of this paper is organized as follows: In Section 2, data from meteorological stations in KSA and the homogeneity of these data are described. Section 3 presents the results of an analysis of monthly, annual and horizontal distributions of rainfall over KSA. Finally, conclusions are offered in Section 4.

2. Data from KSA Meteorological Stations

Because of its low annual precipitation, KSA is commonly

regarded as a dry country. This is a climatic simplification; however,

because precipitation varies over space and time and of the amounts of

precipitation over particular regions of KSA are diverse. Besides spatial

differences, interannual variations of precipitation also occur. The

complexity of the rates of precipitation over KSA derives from the vast

area of the country (about 2,250,000 km2), its wide latitudinal expanse

(15.5°N - 32.5°N) and its pronounced topographical relief. Monthly

Analysis of Rainfall over Saudi Arabia 61

precipitation records are compiled for 28 stations managed by the KSA

Meteorological Organization. The stations are distributed across KSA,

although their spatial density is low and uneven in some parts of the

country. Table 1 gives the name, position, elevation and the available

period of data from each KSA meteorological station.

Studies on data homogeneity are essential to climatology. Homogeneity is manifested differently depending on the climatic element. The values of climatic measures of these climatic elements could be used in estimating daily and monthly averages. Artificial lakes and reservoirs and other man-made changes to the local environment produce sources of inhomogeneity in historical records of climatic data. Homogeneity in rainfall over cities in KSA has been examined by means of the Bartlet test.

Table 1. The name, position, elevation and the available data period for each KSA

meteorological station.

No Name Lat Long Elevation Available Data Years

1 Turaif 31.68 38.73 852.44 1978 --- 2003 26

2 Gurait 31.40 37.28 503.90 1985 --- 2003 19

3 Arar 30.90 41.14 548.88 1979 --- 2003 25

4 Aljouf 29.78 40.98 668.74 1978 --- 2003 26

5 Tabouk 28.37 36.60 444.10 1978 --- 2003 26

6 Hail 27.43 41.69 768.11 1970 --- 2003 34

7 Wejh 26.20 38.47 357.60 1978 --- 2003 26

8 Rafha 29.62 43.49 413.00 1978 --- 2003 26

9 Alqusoma 28.31 46.13 1001.52 1978 --- 2003 26

10 Hafrbaten 27.90 45.53 646.71 1985 --- 2003 19

11 Dhahran 26.25 50.16 16.77 1970 --- 2003 34

12 Ahsa 25.29 49.48 23.73 1985 --- 2003 19

13 Gassim 26.30 43.76 178.17 1978 --- 2003 26

14 New Riyadh 24.92 46.72 613.55 1985 --- 2003 19

15 Old Riyadh 24.71 46.73 619.63 1970 --- 2003 34

16 Wadi Aldwaser 20.50 45.25 635.60 1978 --- 2003 26

17 Madina 24.54 39.69 3.58 1970 --- 2003 34

18 Yenbo 24.14 38.06 1452.75 1978 --- 2003 26

19 Jeddah 21.71 39.18 240.35 1970 --- 2003 34

20 Makkah 21.43 39.79 701.02 1985 --- 2003 19

21 Taif 21.48 40.55 614.39 1970 --- 2003 34

22 Baha 20.29 41.64 1651.88 1985 --- 2003 19

23 Bisha 19.99 42.61 1161.97 1970 --- 2003 34

24 Abha 18.23 42.66 2055.93 1978 --- 2003 26

25 Khamis Mush 18.29 42.80 2093.35 1970 --- 2003 34

26 Najran 17.61 44.41 1212.33 1978 --- 2003 26

27 Sharura 17.46 47.10 724.65 1985 --- 2003 19

28 Gizan 16.90 42.58 7.24 1970 --- 2003 34


Table 2 presents Bartlet test (short-cut) results for mean annual rainfall at each station. The mean annual rainfall seems to be homogeneous except at the Tabouk and Sharorah stations when

( 2 2

max min/S S ) is used with 95% significance as discussed by Mitchell et al.

(1966). The mean annual rainfall amounts at the Aljouf and Abha stations indicate some inhomogeneities.

Table 2. Bartlet test (short- cut) result for the KSA stations (n is the number of terms in

each subperiod k, and k is the number of the subperiod).

Station N k 95%

Significant point Homogeneity

Turaif 13 2 3.28 1.56

Guriat 9 2 4.43 2.17

Arar 13 2 3.28 3.25

Aljouf 13 2 3.28 3.36

Rafha 13 2 3.28 1.48

Tabouk 13 2 3.28 6.23

Alqaisoma 13 2 3.28 1.55

Hail 11 3 4.85 1.68

Qassim 17 2 2.76 2.69

Dhahran 15 2 3.16 2.33

Alwajh 13 2 3.28 3.17

Alahsa 9 2 4.43 3.25

New Riyadh 9 2 4.43 3.52

Old Riyadh 17 2 2.76 1.32

Madinah 17 2 2.76 1.59

Yanbo 13 2 3.28 2.59

Jeddah 17 2 2.76 1.73

Taif 17 2 2.76 2.77

Makkah 9 2 4.43 3.96

Albaha 9 2 4.43 1.85

Bisha 11 3 4.85 1.92

Khamis Moshet 11 3 4.85 3.62

Abha 13 2 3.28 3.31

Najran 8 3 6.94 1.15

Sharorah 9 2 4.43 6.32

Gizan 11 3 4.85 1.57

3. Results and Discussion

3.1 Monthly Average Rainfall

Figure 1(a) shows the average monthly amounts of rainfall for each

month of the year at the Arar, Turaif, Guriat, Aljouf, Tabouk and Hail

stations. The maximum amount of rainfall at these stations occurs in

January, and the average amounts of rainfall in January at all stations


exceeds 10 mm except for Tabouk. The second rainiest month at these

stations is December. Hail and Turaif receive the highest amount of

rainfall during the rainy months of the year. The months from June to

September are the dry months of the year, while the winter and spring

months are the wet months at these stations.

Figure 1(b) presents the average monthly amounts of rainfall for each month of the year at the Alwajh, Rafha, Alqaisoma, Hafr Albaten, Dharan and Alahsa stations. The maximum amount of rainfall at these stations occurs during the winter season excluding November, March and April. These stations do not receive any rainfall during the June to September period. The averages of the monthly rainfall at the Hafr Albaten and Dharan stations are more than 30 mm in January and March, respectively. The period from May to October is the dry period at these stations.

Figure 1(c) shows the average monthly rainfall amounts for each month of the year at the Qassim, New Riyadh, Old Riyadh, Wadi Aldwaser, Sulayel and Madinah stations. This figure indicates that the maximum amount of rainfall at the Qassim, New Riyadh, and Old Riyadh stations occurs in March and April. The maximum amounts of rainfall received at the Sulsyel station are at April. The Wadi Aldwaser and Madinah stations recived less than 10 mm of rain during the rainy months of the year. The period from June to October is the dry period at these stations.

Figure 1(d) presents the average monthly rainfall amounts for each month of the year at the Yanbo, Jeddah, Makkah, Taif, Abbaha and Bisha stations. It is clear that the mountain stations (Taif, Abbaha and Bisha) received the maximum amount of rainfall of this group of stations. The highest values of rainfall at these mountain stations occur during the spring especially in April. Considerable amounts of rainfall at the Makkah and Jeddah stations occur in November, December and January. The three mountain stations received rainfall throughout the year with lowest values in February.

Figure 1(e) shows the average monthly rainfall amounts for each month of the year at Abha, Khames Moshet, Najran, Sharorah and Gizan stations. It is clear that the maximum amount of rainfall at these stations occurs at the Abha and Khamis Moshet stations in March, April, May and August. The mountain station of Abha received the greatest amount of rainfall in KSA (more than 55 mm). The minimum amount of rainfall


occurs during September, October, November and December at these stations.

Fig. 1(a). The average monthly rainfall amounts for each month of the year at the Arar,

Turaif, Guriat, Aljouf, Tabouk and Hail stations.

Fig. 1(b). The average monthly rainfall amounts for each month of the year at the Alwajh,

Rafha, Alqaisoma, Hafrelbaten, Dhahran and Alahsa stations.

0

5

10

15

20

25

30

35

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

pre

cip

ita

tio

n (

mm

)

Alwajh Rafha Alqaisoma Hafr Albaten Dhahran Alahsa

0

5

10

15

20

25

30


pre

cip

ita

tio

n (

mm

)

Arar Turaif Guriat Aljouf Tabouk Hail


Fig. 1(c). The average monthly rainfall amounts for each month of the year at the Qassim,

New Riyadh, Old Riyadh, Wadi Aldwaser, Sulayel, and Madinah stations.

Fig. 1(d). The average monthly rainfall amounts for each month of the year at the Yanbo,

Jeddah, Makkah, Taif, Albaha and Bisha stations.

0

5

10

15

20

25

30

35

40


pre

cip

itati

on

(m

m)

Qassim Riyadh new Riyadh Old Wadi Aldwaser Sulayel Madinah

0

5

10

15

20

25

30

35

40


pre

cip

ita

tio

n (

mm

)

Yanbo Jeddah Makkah Taif Albaha Bisha


Fig. 1(e). The average monthly rainfall amounts for each month of the year at the Abha,

Khamis Moshet, Najran, Sharorah and Gizan stations.

The stations that lie north of 24.5oN do not receive a considerable

amount of rain during the summer months in additions to September. In the winter, the highest amounts of rainfall occur at the stations in the east of the middle of KSA (the Hail, Gassim, new Riyad, old Riyad, Hafr Elbaten and Qaisoma stations). In spring, the southwestern stations and stations to the east of the middle of KSA received higher amounts of rain with the maximum at Abha in March (60 mm). In the autumn, the seven stations of Hafr Elbaten, Qaisoma, Jeddah, Makkah, Taif, Hail and Gizan receive considerable amounts of rain (more than 20 mm). From the seasonal analysis of rainfall, the periods of rainfall over KSA can be divided into two main periods. The first period includes November, December, January, February, March, April and May. About 80% of the total rainfall over KSA occurs during these months. The second period includes the other five months (June through October).

3.2 Annual Rainfall

In this section, the annual amounts of rainfall at 29 meteorological

stations in KSA are discussed. The slopes of the time series trends at

each station were calculated by least squares linear fitting. Figure 2(a)

presents the annual rainfall amounts at the Turaif, Guriat, Arar, Aljouf,

Rafha, Tabouk, Alqaisoma and Hafr Albaten stations for the available

0

10

20

30

40

50

60

70


pre

cip

itati

on

(m

m)

Abha Khamis Moshet Najran Sharorah Gizan


periods. It is interesting to note that there are two peaks in the rainfall

time series for Turaif. The first one occurs during 1979 and the second

one occurs in 1982. The maximum of the annual mean values at Guriat

occurs in 1988 while the minimum values occur in 1993 and 2000. The

maximum annual rainfall received at Arar is in 1988 while the minimum

amount is in 1996. Negative trends can be observed for these three

stations. Although the annual amount of rainfall received at Aljouf is

small, there is a positive rainfall trend. The highest amount recorded at

Rafha is in 1974. Figure 2(a) also shows that the trend of the annual

rainfall amounts at Tabouk and Alqaisoma is negative and the amount of

rainfall received at Alqaisoma is greater than at Tabouk throughout the

period of this study.

Figure 2(b) shows the annual rainfall amounts at Hail, Qassim, Dhahran, Alwajh, Alahsa, New Riyadh, Old Riyadh and Madinah stations during the available period for each station. It is interesting to note that there are four peaks in the rainfall time series for Hail (greater than 20 mm). The first peak occurred in 1976; the second and third were in 1982 and 1984; while the last in 1993. Large variability in the time series at Hail can be observed with a positive trend. The maximum rainfall amount received at Qassim is in 1982 (40 mm), while the minimum values are recorded in 1990. Considerable variability in the time series for Dhahran can be observed with a positive trend. Three maximum values occurred (greater than 20 mm). The first one was in 1972, the second in 1976, while the last in 1982. Although the trend of the time series for Alwajh is positive, it receives small amounts of rain throughout the period. As at most stations, it is clear that a wave length 4 years is the dominant wave of the time series for the Old Riyadh station. Three peaks (greater than 20 mm) in the annual rainfall appeared for this station, one in 1972, the second in 1976 and the last in 1995. A considerable variability in the annual rainfall time series for Madinah is evident, although the amount of rainfall is small throughout the period for this station. The trend for the time series for Madinah is positive.

Figure 2(c) shows the annual rainfall amounts for the Yanbo, Jeddah, Taif, Makkah, Wadi Aldwaser, Albaha, Bisha and Khmis Moshet stations during the available period for each station. It indicates that higher annual rainfall amounts at Yanbo occur in 1992 and 1993, while a lower amount occurs in 1995. The annual amount of rainfall at Jeddah reached 24 mm in 1996, while this amount in other years does not exceeded 10 mm. The lowest value is recorded in 1982. The time series


for Taif follows a wave pattern with 5-year wave length. The maximum values occured in 1992 and 1996. Like in Taif, the maximum annual values at Makkah occur in 1992 and 1996. The trend for these four stations is positive. The trends for the time series for Wadi Aldwaser, Albaha, Bisha and Khamis Moshet are negative. The average values of the annual time series for Nisha and Khamis Moshet are 8.5 and 17 mm, respectively. Figure 2(d) shows the annual rainfall amounts for the Abha, Najran, Sharorah and Gizan stations during the available period for each station. It indicates that time series for Abha is very similar to those for Bisha and Khamis Moshet due to the proximity of these stations. The trend of the last three stations that fall in the same area is positive. The mean annual rainfall for the most stations in KSA was highest in 1982. The trend analysis of the mean annual rainfall at KSA stations indicates a positive trend (wet) at 14 stations (Aljouf, Hafr Albaten, Rafha, Dahran, Alwajh, New Riadh, Madinah, Yanbo, Jeddah, Mekkah, Najran, Sharora, and Gizan). There is a negative trend (dry) at 15 stations (Turaif, Guriat, Rafha, Alqaisoma, Tabouk, Hail, Qassim, Albaha, Old Riyadh, Wadi Aldwaser, Albaha, Bisha, Kamis Moshet and Abha).

3.3 The Horizontal Distribution of Rainfall over KSA

Figure 3(a) gives the names and positions of the KSA

meterological stations, while Fig. 3(b) shows the average annual amounts

of rainfall at KSA meterological stations. It is clear that the maximum

annual rainfall occurs in two regions: The first is east of the middle

region (Hail, Gassim, Hafr Albaten, Qaisoma, Riyad and Dharan) and the

second is the southwest region (Taif, Baha, Khamis Meshet, Abha, and

Gizan). The lowest rainfall values occur in the north and northwest areas.

The southeast area does not house a meteorological station but it is

considered a dry area.

Figure 4(a) shows the average mean amounts of rainfall during the winter in KSA, while Fig. 4(b) shows the average mean amounts of rainfall during the spring in KSA. It is clear that the maximum rainfall during the winter occurs in the north and the middle of the eastern area and over the mountainous area in the southwest region. The highest rainfall amounts in KSA occur during the spring. Similar to the annual values (Fig. 3b), there are two regions with maximum rainfall, the first in the northeast and the second is in southwest of KSA. The maximum amount (21.9 mm) occured at Hafr Elbaten, while the maximum amounts during the spring (44.4, 34.1 mm) occured at Abha and


Khamis Meshet, respectively. Figure 5(a) shows the average amounts of rainfall during the summer in KSA.

Fig. 2(a). Annual rainfall amounts at the Turaif, Guriat, Arar, Aljouf, Rafha, Tabouk,

Alqaisoma and Hafr Albaten stations during the available period for each station.

Turaif

0

5

10

15

20

25

30

1978 1982 1986 1990 1994 1998 2002

Pre

cip

itati

on

(m

m)

Guriat

0

1

2

3

4

5

6

7

8

9

1985 1988 1991 1994 1997 2000 2003

Pre

cip

itati

on

(m

m)

Arar

0

2

4

6

8

10

12

1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

itati

on

(m

m)

Aljouf

0

1

2

3

4

5

6

7

8

9

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

itati

on

(m

m)

Rafha

0

2

4

6

8

10

12

14

16

1970 1973 1976 1979 1982 1985 1988 1991 1994

Pre

cip

ita

tio

n (

mm

)

Tabouk

0

1

2

3

4

5

6

7

8

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Alqaisoma

0

5

10

15

20

25

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Hafr Albaten

0

5

10

15

20

25

30

1990 1992 1994 1996 1998 2000

Pre

cip

ita

tio

n (

mm

)


Fig. 2(b). Annual rainfall amounts at the Hail, Qassim, Dhahran, Alwajh, Alahsa, New

Riyadh, Old Riyadh and Madinah stations.

Hail

0

5

10

15

20

25

30

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Qassim

0

5

10

15

20

25

30

35

40

45

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Dhahran

0

5

10

15

20

25

30

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Alwajh

0

2

4

6

8

10

12

14

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Alahsa

0

5

10

15

20

25

1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Riyadh New

0

5

10

15

20

25

30

1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Riyadh Old

0

5

10

15

20

25

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Madinah

0

2

4

6

8

10

12

14

16

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)


Fig. 2(c). Annual rainfall amounts at the Yanbo, Jeddah, Taif, Makkah, Wadi Aldwaser,

Albaha, Bisha and Khamis Moshet stations.

Yanbo

0

1

2

3

4

5

6

7

8

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Jeddah

0

5

10

15

20

25

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Taif

0

5

10

15

20

25

30

35

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Makkah

0

5

10

15

20

25

1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Wadi Aldwaser

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1991 1993 1995 1997 1999 2001 2003

Pre

cip

ita

tio

n (

mm

)

Albaha

0

5

10

15

20

25

30

1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Bisha

0

5

10

15

20

25

30

35

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Khamis Moshet

0

5

10

15

20

25

30

35

40

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)


Fig. 2(d). Annual rainfall amounts at the Abha, Najran, Sharorah and Gizan stations.

It indicates that the lowest amount of rainfall in KSA falls is during the summer. Except the southwest area, the amount of rainfall in the summer in the other areas is very low. The maximum amount of rainfall in the summer occurs at Abha (16.3 mm) and Khamis Meshet (23.4 mm). Figure 5(b) presents the average amounts of rainfall during the autumn in KSA. It indicates that six stations have an average amount greater than 10 mm (Hail, Hafr Elbaten, Qaisoma, Makkah, Taif and Gizan). The northwest and the southwest areas may be considered to be drier areas during autumn.

4. Conclusion

In this paper, the climatology of monthly and annual rainfall in the

Kingdom of Saudi Arabia has been analyzed using the available data

from 29 meteorological stations. The mean amount of annual rainfall

seems to be homogeneous except at the Tabouk and Sharorah stations,

according to the Bartlet test with a 95% significance level. Analysis of

these data shows that the highest amounts of rainfall occur during the

Abha

0

5

10

15

20

25

30

35

40

45

50

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Najran

0

5

10

15

20

25

1978 1981 1984 1987 1990 1993 1996 1999 2002

Pre

cip

ita

tio

n (

mm

)

Sharora

0

2

4

6

8

10

12

14

16

18

20

1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)

Gizan

0

5

10

15

20

25

30

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Pre

cip

ita

tio

n (

mm

)


Fig. 3: A) The names and positions of KSA meterological stations, B) The average amounts

of rainfall at KSA stations.


Fig. 4: A) The average amounts of rainfall during the winter in KSA, B) The average

amounts of rainfall during the spring in KSA.


Fig. 5: A) The average amounts of rainfall during the summer in KSA, B) The average

amounts of rainfall during the autumn in KSA.


spring in the southwest, middle and east regions of KSA. The second

highest amounts of rainfall occur during the winter in the east and

northeast of KSA. Summer is the season of lowest rainfall in KSA,

where, except in the mountainous area in the southwest region, the

amount of rainfall is very low. While the horizontal distribution pattern

of rainfall in the autumn is somewhat similar to that of in the spring, the

amount of rainfall in the autumn is less than in spring.

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