Climate of Sudan

Mon, 25 Sep 2017



 

Dr. Mohamed Kabbahi Abdalla

Abstract

This paper tackles the topic of climate in Sudan, as the climate imposes direct effects on different aspects of life for the entire country of Sudan. The paper aims to elaborate on climatic elements and factors that control the climate of Sudan.   Moreover, the researcher has studied the importance of climate and its effects on Sudan's socioeconomic activities. Furthermore, the paper has discussed some previous attempts made by scholars to classify Sudan's climate.

To achieve these aims, the researcher has used different methods including the analytical statistical and descriptive approach. These approaches have been adopted to analyze obtained climatological data from Sudan’s meteor-logical authority for the period of 1981 to 2010 for nine selected stations, representing eastern, western, northern and central Sudan. The obtained data has been analyzed and tabulated into tables and transformed into maps and graphs to show the monthly maximum, monthly minimum and the monthly mean temperatures. In addition, the pressure distribution for the months of January and July over Africa and the adjacent areas has been discussed.     

In relation to pressure distribution over the surroundings to Sudan, the prevailing surface winds were outlined including both the dry north- east trade winds and the moist south west winds which cause Sudan’s summer rains. The researcher has discussed Sudan's rainfall in terms of monthly and annual distribution. It is noteworthy that special attention has been given to the rainfall; apparently as a determinant factor for the success or failure of the entire country.

In addition to that, the researcher has given an account on climatic classification as a tool used by geographers and scholars in other disciplines to classify the world into climatic regions. The researcher also shed some light on the definitions, the objectives, and the types of climate classification.  Some previous climate classifications for Sudan were based on empirical classifications and have been discussed.  Finally, the researcher concluded this paper with some remarkable insights into previous Sudanese climatic classifications.

 

 

 

Preface:

Climate and weather are two sides of the same coin, so deliberation on Sudan’s climate and factors that influence it will only be complete when the relationship between them becomes clear. Climatology is a branch of natural geography, but it is closely related to meteorology because the two sciences, climatology and meteorology, tackle subjects that discuss the general condition of climate. Nevertheless, the two sciences are different in their methodologies and purposes, besides that a climatologist largely depends on outcomes of meteorological measurements. However, both climatology and meteorology aim to explain spatial and time variations of climatic conditions with differences in the long span of these disparities.

For the climatic image/condition to be more blatant, it will be necessary to define climate in order to show the way it can be studied and factors that control it and its impacts on natural or human environments. Nevertheless, geographers and meteorologists or other scientists agree upon the way climate is defined. To them, all climate represents the prevailing climatic condition in a certain place during a specific time span when all climatic conditions, regular and irregular ones, occur. However, these scientists differ on how long the span of this climatic condition is, because while some of them think it is for 35 years (Brookings Cycle), some others state it is only 11 years (Sunspot Cycle 11.3) (Musa, 1992). Therefore, to define the nature of the prevailing climate, the majority of scientists propose the period is 30 years while depending on what the World Meteorological Organization (WMO) confirmed as record periods, namely 1901 – 1930, 1931 – 1960, and 1961 – 1990.

As to the other side of the coin, i.e. the weather, it represents the transient climatic condition over a certain region, to wit, the climatic condition frequenting over a place during a short period of time which maybe a day or a part of the day or even more than one day if factors causing specific climatic conditions are invariable in the latter case. Now, with the difference between climate and weather being explained, it can be said that climate is the arithmetical average for all weather conditions which frequent over a certain region and during a specific period of time equaling 30 years.

Climatology focuses on tackling weather pattern, types and conditions according to physical laws regulating weather with the resulted climate systems, which differ according to conditions of the prevailing weather. Again, climatology is concerned with studying weather nature and all elements involved in formulating the different weather phenomena like clouds, rainfall/ precipitation and storm, whose general outcome adds an exceptional climatic panorama over a region.

It is critical that the climatic condition in a certain place is not represented by one element like temperature or winds or whatever, because climatic condition is an outcome of the interaction of all climate elements which are represented by temperature, atmospheric pressure, winds, air humidity, features of condensation and forms of rainfall. Notably, every element of the above mentioned is a result of an interaction of a group of factors. These factors include location according to latitude, distribution of land and water, i.e. being closer to or far from water bodies, height above sea level, sea currents and vegetation cover. In the following, we can follow up the interaction between climatic elements and their factors that affect climate in Sudan. Understanding the outcomes of interaction between climatic elements and factors are themselves a climatic type of a certain region.

Sudan climate:

Sudan’s climate is not separated from the general climatic condition and how a condition is affected with some factors may be closer to or further from this climate. This will be depicted while explaining climatic elements and factors that identify Sudan’s climate.

Sudan’s climate is generally described as a hot and tropical one. The climate is tropical because the whole Sudan is located within the zone of northern tropical latitudes, i.e. in the region where the sun perpendicularly passes over during the northern summer season in which the sun virtually moves from the Equator towards Tropic of Cancer 23°5′and, vice versa, from Tropic of Cancer southwards to the Equator. On another hand, Sudan climate is hot because, according to Barber in 1961, there is no region in Sudan over which the sun does not perpendicularly pass twice a year. It is clear out that the virtual sun movement and its perpendicular passing goes over the Equator, on 21st March and on 21st September, it perpendicularly passes twice over every region in Sudan. Here, to begin with the temperature element for its climatic importance.

 

Temperature

Temperature is the most important element of climate because of its direct and obvious impact on all other elements. In fact, temperature directly affects atmospheric pressure and its distribution and, thus, affects wind movement, evaporation, humidity and condensation as well as it largely and immediately affects distribution of different kinds of life.

It is noted that all regions of Sudan are marked with high temperature with temporally and spatially relative variations of temperature. In fact, these relative disparities of temperature can partly be referred to the different latitudinal locations inside Sudan and to the virtual sun movement between the two tropics of Cancer and Capricorn. It is well known that the highest temperature may reach upwards of 40 degree Celsius given the highest, medium and lowest temperatures at the daily, monthly and yearly levels. However, in northern Sudan, summer months in Dongola are the hottest ones, i.e. April through August, as it is illustrated in table (1) and figures (1) and (2) and that the highest temperature zone creeps gradually behind the sun (Al Tom, 2010). As to lowest temperature, it ranges from 6 degrees in some parts of the Northern State and gradually rises to reach 24.8 degrees in central and southern Sudan.

Table (1): Monthly average for maximum and minimum temperature in stations of Dongola and Atbara during 1981 – 2010

Station/ months

Jan.

Feb.

March

April

May

June

July

August

Sep.

Oct.

Nov.

Dec.

 

Dongla

Maximum

Temperature

26.8

29.2

33.7

39.1

42.2

43.3

43

42.8

42.3

39.1

32.5

28.5

 

Minimum Temperature

9.3

10.8

14.7

19.6

23.9

25.3

26.5

26.8

26.1

22.6

15.6

11

Atbara

Maximum

Temperature

30.9

33.8

37.2

41

43.4

43.9

41.7

41.6

42.1

40.2

35.7

32.4

 

Minimum Temperature

14.6

16.2

18.8

23

26.6

28.5

27.9

27.2

27.7

25.5

20.4

16.5

 

                                                       

 

Source: Meteorological Authority: the writer’s work 2015

 

               Figure 1: Maximum and minimum temperature in Dongola from 1981 to 2010

             Source: Meteorological Authority: the writer’s work, 2015

 

 

 

 

                 Figure 2: Maximum and minimum temperature in Atbara from 1981 to 2010

                Source: Meteorological Authority: the writer’s work, 2015

In the same context, April experiences clear height in temperatures ranging between 36 – 41 degrees Celsius in central Sudan and the north eastern part of it. These high temperatures are attributed to two factors, the first of which is the lack of cloud coverage that can rebuff sun rays and alleviate their effects onto the Earth’s surface. Thee second factor is the dominance of the dry north-eastern winds across that region of Sudan.

 

Generally, high temperatures in Sudan are notable because of the following factors:

Lack of cold fronts over Sudan during the dry season.

  1. Fading and relegation of high temperature pressure over the Sahara.
  2. Westwards intensification and expansion of low temperature pressure over the Arab desert.
  3. Emergence and intensification of Sudan’s low temperature pressure which is connected with the two low temperature pressures over Arab Desert and the Saharan Desert.
  4. Retraction of intertropical convergence zone outside of Sudan and that no humid winds can be allowed in while dry north-eastern winds will completely prevail over the region causing high temperatures.

 

Atmospheric pressure and winds:

Weather movement are an indirect reflection of the unequal heating of earth’s surface as well as it is of earth’s rotation around itself. Here, it is necessary to differentiate two kinds of movement, the horizontal movement represented by surface winds and the weather vertical movement represented by upward and down movements of air. It is worth mentioning that Sudan has Convective Rainfall. It is significant that atmospheric movement is of paramount importance as it helps balance spatial and earthly temperature besides carrying humidity and clouds from place to place. So, atmospheric pressure and winds, spatial and surface, work within equal systems each of which trigger off each other.

First: atmospheric pressure

Atmospheric pressure is the force exercised by the air encircling an area unit. Arithmetically, the weight of a pillar of air whose base is one square centimeter, extending from sea surface up to atmosphere ceiling, is estimated to be 1000 grams. Additionally, air exercises under this weight of pressure on the earth’s surface equaling, at atmospheric average record conditions, 1013.2 millibars at sea surface level (Musa 2014, p. 65). Atmospheric pressure is measured with a barometer instrument and as to atmospheric pressure distributions on maps of weather and climate; they are represented by the equal pressure lines (Isobar). However, it is known that there are two main models of pressure, high and low pressures for which the equal pressure line 1013.2 millibars at sea surface level is marked out. These two models of pressure appear on maps of weather and climate as a semi-circular area in which equal pressure lines roam about a maximum central value in high pressure and a lower one in low pressure as shown in figure 3.

 

 

 

 

Figure 3: Types of high and low pressures

Source: Musa, 2014, p. 67.

 

 

What is mentioned before is about atmospheric pressure, along with its instruments, means of measurement and its representation on maps. In continuation, atmospheric pressure as a climatic element, is related to distributions of atmospheric pressure in Sudan. Given that Sudan is affected with what runs around it of weather phenomena, closer to and far from it, with what surrounds it of land and water, we will address distributions of atmospheric pressure in Sudan in January and July, both of which represent the average atmospheric condition over Africa. Moreover, these distributions are of paramount importance to be addressed along with movement of the winds which blow over Sudan and to what these winds bring about of weather and climatic phenomena.

 

Distributions of atmospheric pressure and movement of winds:

In order to study a climate of a certain country it is necessary to study atmospheric pressure systems with their distributions and winds by which that country is affected. All this aims at defining the source region of the winds that prevail over in the different seasons of the year,which again, entail studying expansive regions around that country.

 

In fact, there is no accurate and convincing definition of yearly seasons in Sudan in which the situation ranges from rainless desert in the north to a summer rain belt where the amount of rainfall increases towards the south. However, in Central Sudan, yearly seasons can be divided according to the difference of latitudes as follows:

  • Winter season or the dry season (December – February).
  • Progress of monsoon season (March – May).
  • Rainy monsoon season (June – September).
  • Retracting monsoon season (October – November).

Distributions of atmospheric pressure and monsoons will be discussed in a separate chapter. In relation to maps of distribution of atmospheric pressure which are built on old meteorological data, they can offer an approximate image/condition of this distribution, yet they represent general features of atmospheric pressure and winds in Sudan.

 

In the dry winter season, represented by January, distribution of atmospheric pressure will be as illustrated in figure 4 and prevailing winds are illustrated in figure 5.

 

Figure 4: distribution of atmospheric pressure in African continent in January

Source: Mohammed Kabbashi Abdullah, 1998.

 

 

 

                 Figure 5: winds prevailing over African continent in January

                 Source: Mohammed Kabbashi Abdullah, 1998.

 

 

In figure 4, distributions of atmospheric pressure are as follows:

  1. Desert atmospheric high pressure: is an extension of the Azores atmospheric high pressure which represents subtropical atmospheric high pressure in the northern hemisphere.
  2. Arab desert high pressure: it is also a part of the subtropical high pressure in the northern hemisphere.
  3. Atmospheric high pressure over Balkan plateau in Central Asia.
  4. Atmospheric low pressure over Central Africa.
  5. Atmospheric low pressure over central and eastern Mediterranean.
  6. Intertropical convergence zone which separates air masses which are accompanied with trade winds coming from source regions north and south to the Equator.

 

It is notable that atmospheric high pressure over the Sahara desert controls the movement of winds that blow over Sudan where north eastern trade winds prevail over the whole country except the Red Sea coast. In addition, this atmospheric high pressure extends up to great heights with dynamic movement and, as a result, dry air slides down while its temperature mechanically rises. This phenomenon makes dry winds prevail over while the more they move southwards, the more their temperature increases.

 

In regard of the dominant atmospheric low pressure over the Mediterranean, it poses an air domain creating cold waves coming from central Asia to Western Europe and hence these waves move across the Mediterranean over Arab Desert and end up in the Arab Gulf. On another hand, Sudan’s weather is affected by the passage of these fronts and the temperatures that slide down in the north and northern central parts of the country.

 

The season during which seasonal winds progress on, March to May, represents a transitional season between the dry season of winter and the rainy season. That season is followed by the period when south western rainy seasonal winds progress on from June to September; as shown in figures (6) and (7).

 

Atmospheric low pressure over north-eastern Sudan is called Sudan temperature low pressure. This low pressure causes south western seasonal winds to progress on and, in the interim, intertropical convergence zone advance in a continuous movement from the south to the north in March. After that, intertropical convergence zone penetrate northwards through Sudan during June and July to reach its northern furthest point in August. Then, the intertropical convergence zone soon retreats in October and November and completely fades away from Sudan in November.

 

 

Figure 6: Distribution of atmospheric pressure in African continent, JulySource: Mohammed Kabbashi Abdullah, 1998.

 

 

 

                      Figure7: Winds prevails over African continent, July

                      Source: Mohammed Kabbashi Abdullah, 1998.

 

 

 

Rainfall in Sudan:

The temperature element, as a climatic element, is of natural importance, yet this importance does not amount to that of the rain element in that the rainfall is a more decisive factor in many aspects of life in Sudan.

Rains represent the more effective climatic phenomenon to humankind in Sudan. This phenomenon is the main controller in defining livelihoods and regulating utilization of land in the different regions of Sudan. Moreover, the two professions of agriculture and grazing, depend on rainfall and even other crafts are in some ways affected with the amount of rainfall in Sudan.

For rain to fall in Sudan or in other tracts of the world, it would be necessary for some physical operations to take place on the earth’s surface and its atmosphere. However, those operations are subject to several factors occurring in different times and places but, for rain to pour there should be a large, indispensable quantity of water vapor with operations of condensation to create clouds. Those physical operations are significant and should be heavily considered when discussing rainfall in Sudan. Here, it is critical that rains in Sudan are related with an atmospheric phenomenon called the intertropical convergence zone, a region at which tropical winds blow from the two hemispheres and converge. Sudan’s rains, excluding the Red Sea region, fall during months of the northern summer (June to September).

Professor Mahdi Amin El Tom, 2005, stated that distribution of rains in Sudan are generally marked with simplicity and incrementalism while he explains that the nature of steppe/flat land of Sudan and the fact that this land is free from terrain inhibitions help humid south western winds penetrate from the far south to the far north of the country without being obstructed by a mountainous obstacle.

Nature of rain and its distribution in Sudan:

The nature of rain and its distribution in Sudan can be summed up in the following points:

  1. As far as the duration of the rainy season and quantity of rain are concerned, the amount of heavy rains gradually decrease from south to north because rain-causing humid winds lose their burden of humidity whenever they progress northwards. In this regard, the duration of the rainy season and heaviness of rain vary according to the difference of latitudes as is clarified in the following stations:
  • At Juba station in Southern Sudan, on latitude 50 north, the duration of the rainy season continues for about nine months from March to November (This is to be retrospectively considered before separation of Southern Sudan in 2011).
  • At Malakal station, on latitude 9.50 north, the duration of the rainy season continues for seven months (April – October).
  • At Kosti station, on latitude 130 north, the duration of the rainy season continues for four months (June – September).
  • At Khartoum town, on latitude 15.50 north, the duration of rainy season continues for three months (July– September).
  • At Atbara town, on latitude 17.750 north, the duration of the rainy season continues for about two months (July – August).
  • However, there is no rainy season in the Dongola town which is located on the latitude 190 north nor is there one at the WadiHalfa town which lies on northern Sudanese border.
  1. Amounts of rain vary from north to south in that the more we progress from the south to the north of Sudan, the more the rates decrease (as shown in figure 8), notably, rains may not fall for many years in northern Sudan (Dongola – Halfa) for two factors:
  1. Dominance of dry north eastern winds blowing from over the land.
  2. South western winds, when arrive at this region, they become dry as they lose their burden of humidity while blowing from south to north.

 

 

Figure 8: Annual amounts of rains (in millimeters)

Source: researcher’s work, adopted, Tom and Abdullah, 2010. (p. 51)

 

  1. August is the rainiest month in the entire country of Sudan. The intertropical convergence zone in this month reaches the farthest point of its northwards advance and, thus, it leaves all Sudan south behind. Additionally, figure 9 represents the annual average of rain in some of the selected stations of eastern, western, northern and central Sudan.

 

 

 

Figure 9: Annual average of rain (millimeter) in selected stations of Sudan during 1981 – 2010

Source: Meteorological Authority – researcher’s work 2015

 

 

  1. The more torrential rains fall out of cumulus clouds and scarlet cumulus clouds coming from the east. These clouds are marked with thunderstorms and lightening which in Sudanese tradition called the Abbadilightening whose clouds inevitably heavily rain.
  2. Highlands of Ethiopian plateau play an important part in distribution of rain amount from east to west in Sudan, that is because rainy cumulus clouds which are formed over Ethiopian plateaus move westwards in the afternoon and torrentially rain on eastern parts of Sudan such as stations of Damazin and Gedarif compared with stations of Nyala and Obeid in western Sudan (see figure 9).
  3. Rains of Sudan fluctuate from year to year due to the seasonal nature of winds that create them and the relegation of high Azores pressure northwards and southwards with the virtual sun movement between Equator and tropic of Cancer. Therefore, fluctuation of rainfall and the decreasing amount from year to year has caused cases of drought which have stricken Sudan in the years 1972, 1983, 2004 and 2015. These droughts have rendered the agricultural seasons failures and brought about aridity and famine. That drought either wholly occurred as in the years 1972 and 1983 or partly as in the year 2004 in eastern Sudan.
  4. The start and distribution of rain during rainy season is connected with the movement of the intertropical convergence zone. In this respect, movement of ITCZ determines the amount of rain that falls south of this zone, because the more the ITCZ advances northwards in a balanced movement, the more rain will be well distributed during the whole season. Here, it is critical that advancement of ITCZ farthest to the north, outside Sudanese borders, causes torrential rains that in turn create floods like in the case of Khartoum in 1988.
  5. Unlike other parts of Sudan, rains in eastern Sudan fall in the winter (November – February). These rains are caused by hurricanes that are confined to the narrow plain lying between the Red Sea and its hills. Nevertheless, west slopes of the Red Sea experience some summer rains that fall in the other parts of Sudan.

 

Climatic classification in Sudan:

Climatic classification is a process aiming at the definition of distinctive climatic zones on the earth’s surface where every climatic zone is distinguished with one climatic attribute or a group of specific climatic characteristics that make it distinguishable in comparison with other zones. For this reason, geographers are concerned with the issue of climatic classification (Abdel Wahab, 2007).

The climate prevailing over every region depends on different factors, each of which particularly affect the climate. These factors often operate with each other in a way that is difficult for us to discriminate the impacts of any of these factors and effects resulted from other factors. However, these factors combined make for every area on the earth’s surface a special climatic characteristics which are more or less different from other places. Climatically, it is rare to find two places which are absolutely similar in their climatic conditions, for instance if there is no difference in quantity of rain, there would be difference in temperature and, likewise, if there is no difference in the two annual rates of rain and temperature, there may be difference in their distribution among the year. That is besides variations in other elements like humidity, amount of solar radiation and the direction and speed of wind, etc. In that regard, there may be two cities located on the same latitude, yet climate is contrasting. For example, Cairo and Galveston are nearly located on the same latitude, because while the former lies on latitude 300 north, the latter lies on latitude 290 25' north. Notwithstanding the same location, Cairo’s climate is a continental one because it is largely surrounded by land while Galveston’s climate is affected by its coastal site which is affected by the Gulf of Mexico and the humid winds blowing over it.

With all that in mind, why climatic classification utilized? Why is the Globe divided into climatic regions?

In this context, there are conflicting opinions on the use of climatic classification. One opinion sees that there is no use for climatic division. Those who adopt this opinion depend on the prevailing premise that there are no two places absolutely similar in their climatic characteristics, but even every house and every room has its own special climate which is more or less different from other houses or rooms (Al Tom, 2005). 

Notwithstanding these differences and opinions doubting the expediency of division of the globe into climatic regions, there are several academic and practical reasons sustaining the idea of climatic classification. Some of these reasons are facilitation of climate study and determination of agricultural activities or species of yields or the specific crop in its appropriate region. Therefore, according to these objective reasons, climatologists divided the globe into climatic regions. In this process of division, criteria which were used in the different climatic classification varied, as some climatologists depended on a single variable, like temperature, as a main criterion for differentiating different types of climate. One of eldest climatic classifications built on merely temperature was the classification Greeks used for the highest temperature zones of the world (hot, cold and moderate domains). Additionally, the usage of temperature was developed as a criterion for classification by means of the different thermal rates like annual and monthly rates; besides that annual temperature range, which was used as a criterion for classification. Here, there is Gorczynski Classification which depends on the continental degree to determine the region. A continental degree is defined as the amount of annual thermal disparity between coldest and warmest months of the year, thus, the more annual thermal range increases, it becomes evident that the continental average is high and climate is more extreme while the opposite is true. In addition to the annual thermal range, Gorczynski introduced the place width degree and set the following equation:

 

Continental degree =(  )    63.3

However, by applying this equation, Gorczynski reached some values through which he determined the continental degree of the region as shown in table 2.

Table 2: Limit values of continental degree of climate

Continental degree

Climate nature

Less than 30

Sea climate

30 – 40

Semi-sea

40 – 50

Semi continental

Above 60

Extreme continental

 

                                                              Source: Abdel Wahab, 2007

 

              Likewise, other climatologists only used precipitation factors as a base for climatic classification, because many regions resemble each other in the thermal element such as tropical regions in which levels of temperature are generally high. On another hand, abundance of water is a decisive factor for growth and prosperity of vegetation. Yet, when the idea of precipitation emerged as a base for climatic classification, consequently began differences about the relative importance of precipitation rates. At this point, rates of virtual value of rains began to be used since this virtual value determines the available amount of water needed for the growth and prosperity of vegetation. Anyhow, the well-known American scientist Thornthwait, who produced his famous classification which was used by many researchers, himself, was one of the many who used that classification.

            Other climatologists used some variables instead of only one variable. The most famous of these climatologists is the German Vladimir Cubin. Cubin combined elements of temperature and rain for their vital importance on biological activity. Differently, there is another group who used air masses and winds as a base for dividing the globe into climatic regions, considering that difference of temperature and humidity of winds is the primary cause of weather variations, andthus, variations of climate. Equally, there are climatologists who used other variables.

            In relation to climate studies, climatologists found it difficult to study the conditions of every single place in detail. Therefore, it is necessary to draw general division for the world, whereby regions which are similar in their climatic conditions can be put under one climatic section regardless of simple differences which discriminate some regions in relation to other ones. In such a way, climatologists could divide the globe into climatic regions, each of which has its own features while this region includes all areas which reflect these panoramas. 

            Climatologists nearly unanimously agree that any climatic division should originally depend on the main elements of climate, namely temperature and rains with distributing these two elements through months of the year. These two elements, however, generally control distribution of flora and fauna on the earth’s surface and are directly or indirectly involved in formation of surface features and, additionally, affect the rest of other climate elements.

 

Climatic classifications are set in three main groups which are:

  1. Empirical classifications: These classifications depend on linking climate with distribution of the main environmental forms like natural plants and soil. The examples of these classifications are those of Kubin, Thornthwait and Trioartha. It is important for these classifications to include climatic divisions which resemble each other in climate-connected environmental conditions regardless of factors that intervene in the formation of their climate (Shureih, 1967). However, one of the more important classifications is Kubin’s in 1900, which he amended in 1918 and, thereafter, he inserted slight amendments to it in 1936. Additionally, one of the more important classifications is Thornthwait’s in 1948. 
  2. Genetic/ Fundamental classifications:  These classifications consider climate-forming factors such as astronomical location, geographical location, general zones of atmospheric pressure and air masses. Some of these classifications are those of Terjung and Oliver.
  3. Human classifications: here the impact of climate on human life and activity are considered such as human feelings of convenience and inconvenience and whether human beings can work and exert effort for work. Comparatively, these classifications are of less usage in comparison with the aforementioned two classifications and are barely used in certain places.
  4. The foregoing presentation is an inclusive views and image about climatic classification concerning identity, purposes and more famous types of climate. This whole image is significant to see through it the partly climatic classification of Sudan climate. However, some of the more important climatic classifications applied to Sudan are Vladimir Kubin’s and Thornthwait’s, the latter of which was proposed in 1948 (as shown in table 3). These two classifications are widely renowned among researchers, many of whom applied them worldwide as well as to Sudan.

Table 3: Kubin climatic regions

region

code

Thermal tropical regions

(A)

Hot tropical with torrential rains all the year

(Af)

Hot tropical with winter drought

(Aw)

Hot seasonal tropical

(Am)

Dry regions

(B)

Semi-desert hot regions

(Bs h)

Semi-desert cold regions

(BSK)

Hot desert

(BWh)

Cold desert

(B W K)

Moderate regions

(c )

Moderate – rainy all the year with hot summer

C f a

Moderate – rainy all the year with warm summer

C f b

region

Code

Moderate – rainy all the year with short cold summer

C f c

Moderate with hot and warm summer

C s a

Moderate with dry and warm summer

C s b

Moderate with dry winter and hot summer

C w a

Moderate with dry winter and warm summer

C w b

Cold regions

(D)

Cold – rainy all the year with hot summer

D f a

Cold – rainy all the year with warm summer

D f b

Cold – rainy all the year with cold short summer

D f c

Cold – rainy all the year with harsh winter

D f d

Cold with dry winter and hot summer

D w a

Cold with dry winter and warm summer

D w b

Cold with dry winter and short cold summer

D w c

Cold with dry and harsh winter

D w d

Polar regions

(E)

Tundra

E T

frost

E F

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Source: Al Tom, 2005

In this context, some of researchers who tried to divide Sudan into climatic regions by using different criteria are the following:

  1. Ireland, 1948, who used latitudes to divide Sudan into three climatic regions,
  2. K. M Barbour, 1961, who applied Kubin’s classification and, accordingly, concluded that dry and semi-dry regions represent two thirds of Sudan. Besides, Barbour divided Sudan into climatic regions according to seasons of the year in Sudan as shown in figure 10.

 

 

 

Figure 10: climatic regions – Barbour, 1961

  1. On his part, Yusuf Fa’id divided Sudan into five climatic regions according to Bailey System as shown in figure 11.

 

 

 

       Figure 11:  Sudan climatic regions according to Bailey System

Source: researcher’s work, adopted and built on Fa’id classification, 1965

 

  1. Babadaks, 1971, used amount and rates of monthly rains and maximum evaporation (water balance) and so divided Sudan into five climatic regions as shown in figure 12.

 

 

 

Figure 12: division of Sudan into climatic regions by using water balance

Source: researcher’s work, adopted, Babadaks 1971.

 

  1. Siddig Ahmed Awadallah, 1981, tried to divide Sudan into climatic regions using Penman Equation. By so doing, Awadallah divided Sudan into five climatic regions as shown in figure 13.

 

 

 

 

Figure 13: Sudan climatic regions according to Awadallah, 1981

Source: researcher’s work, adopted, Awadallah 1981.

 

  1. According to both Kubin and Thornthwait classifications, professor Mahdi Amin AL Tom, 2005, stated division of Sudan into climatic regions as shown in figure 14.

 

Sudan Climatic classification ( Thronthawite)    Sudan Climatic classification ( Koppen)

Figure 14: Sudan climatic regions

Source: Source: researcher’s work, adapted, Al Tom 2010

 

  1. In 1978, Arab Organization for Agricultural Development divided Arab Homeland into climatic regions and, according to that classification; Sudan was divided into specific regions. On his part, Hussein Adam, 1990, developed that classification using Russian Silyanov laboratories. In this process, Adam amended the boundaries of climatic regions in order to be suitable for Sudan thermal conditions.  

 

Silyanov laboratories =

Using this equation, Adam divided Sudan into seven climatic regions as shown in figure 15

Figure 15: Sudan climatic regions – Hussein Adam, 1978.

Source: researcher’s work, adopted, Adam 1990.

Considering the classification of Sudan’s climate and its division into climatic regions, according to the famous classification of researchers, it will be clear that these regions carry general characteristics which can be summed up in the following:

  1. Their latitudinal extension across Sudan and most of the regions generally extend from east to west.
  2. Amount of humidity begins in humid regions in the south and ends up in dry regions in the north where it decreases according to distribution and gradation of rain from south to north.
  3. Presentation of classifications used for classifying climate in Sudan show that most climatic classifications applied to Sudan are experimental classification because these latter classifications are the more famous and widely applied all over the world.
  4. Application of these plentiful classifications in Sudan may be attributed to the fact that Sudan is an agricultural country and that their application is useful for agriculture which represents the primary human activity. Moreover, these classifications depend on water balance and amount of humidity, the two of which are crucial in all types of agriculture in Sudan.

 

References:

  1. Al Tom, Mahdi Amin (1974) Sudan climate, Arabic research and studies institute, Cairo.
  2. Al Tom, Mahdi Amin (2005) climate, education program, the Open University of Sudan, first edition, publications of the Open University of Sudan.
  3. Al Tom and Abdel Rahman, Mahdi Amin and Babikir Abdullah, natural and human geography of Sudan.
  4. Sharaf: Abdel Aziz Tarih () climatic and vegetation geography with application on climate of Africa and Arab World, 11th edition, University Knowledge House – Alexandria.
  5. Abdel Wahab: Samih (2007) foundations of contemporary climatic geography, Knowledge House for Human Development – Riyadh.
  6. Awadallah, Siddig Ahmed, 1981, some aspects of agricultural climate – a work paper presented on environmental deterioration in Gedarif –Institute of Environmental Studies, University of Khartoum.
  7. Fa’id, Yusuf Abdel Hameed (1989) geography of climate and vegetation, Dar al-Nahda al-Arabiya,

Beirut.

  1. Muzamil Othman Saied (2010) impacts of climate factors on production of fruits and wheat in the Northern State – an applied climatic study – an unpublished Ms Thesis – University of Khartoum.
  2. Musa, Ali Hassan (2014): Basics of Climatology, Dar Al fikrAlmoasser, Beirut.

References in foreign language:

  1. Abdalla: Mohammed Kabbashi: 1993.  The climate of the red sea area Sudan unpublished                    M.A. Thesis, university of Khartoum.
  2. Abdalla: Mohammed Kabbashi (1998) dust storms and their environmental hazards in the   Gash and Tokar area. Eastern Sudan.  A PhD, unpublished Thesis, university of Khartoum.
  3. K.M. Barbour (1961), Republic of Sudan, Regional Geography. University of London press                 LTD Warwick square, London E.C.4.

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