Application of two meteorological drought indices in central Sudan

الملخص EN

three climatic variables, namely daily rainfall, maximum and minimum temperature values, for the period of 30 years from 1988 to 2017, were considered for nine observation stations throughout Sudan.

Two methods of Aridity Index (AI) were utilized based on monthly/seasonal and annual rainfall and temperature values to obtain the aridity conditions in Sudan during the study period.

Furthermore, the main objective of this study is to measure drought aridity in Sudan.

Other objectives are to measure monthly/seasonal or annual aridity and humidity conditions over the same area to identify climatic classification for the nine stations, which are included in this study.

Finally, to create a map, which represented all drought, aspects to show the most affected areas throughout the study period and to help decision makers in the natural resources sectors.

For this reason, two meteorological drought indices were applied based on climatic variables.

Thus, the monthly/seasonal Aridity Index was estimated by using Thornthwaite method, and the study area was classified into five categories, namely, Arid conditions (൏ 16), are recorded at Atbara and Khartoum around the 30 years, whereas, Semi-arid are observed at Fasher, El Obaied and Kassala during spring, autumn and winter, and Humid conditions (16-31), observed for the same stations in summer.

Very humid (൒ 128), recorded at Kadogli, Genena and Gadarif during summer seasons.

The annual AI was applied by using De Martonne method.

Therefore, the results outlined into four categories mainly, Arid (values ൏ 5ሻ at Khartoum and Atbara stations, Semi-Arid (values -5) at Fasher and Kassala stations, Sub-Humid (– 10) represented by Genena, Obaied and Kosti and Very Humid (values ൒ 30ሻ are represented by Kadogli, and Gadarif.

These results indicate that drought in the study area has occurred frequently, and it has spreaded quickly southwards.