Summary
Ethiopia has been ravaged by severe drought for many of the last 35 years, primarily due to the failure of its main (Kiremt) rainy season in boreal summer. Kiremt quality results from the timing of its onset and cessation and the frequency and duration of intervening dry-spells. To address these key aspects of Kiremt variability, we analyzed specially constructed sets of research quality, daily rainfall and rawinsonde data for the longest available periods (25–57 years).
The analyses produced wide-ranging results of considerable value to Ethiopia. The long-term average spatial progression of the southwest-to-northeast Kiremt onset and its reverse cessation are documented, along with measures of their interannual variability. Treated on a similar geographical basis is the local vulnerability to Kiremt interruption by dry-spells. Rawinsonde data for central Ethiopia are analyzed to place these long-term mean surface Kiremt characteristics in the context of the annual cycles of tropospheric wind, temperature, and pressure.
Investigation of the rich interannual Kiremt variation focuses on onset, cessation, and growing length (which excludes dry-spells) anomalies. The analyses begin with the compositing of indicative tropospheric profiles for sets of extremely dry and wet Kiremt seasons. This is followed by examination of 1961–99 time series of the above Kiremt parameters, which prompts case study investigations of the highly contrasting 1984 (very dry) and 1996 (much wetter) Kiremts in terms of both Ethiopian rainfall and the tropospheric circulation of the surrounding region. Finally, correlation analyses are used to investigate relations between the above key Kiremt parameters for the most drought-prone (northeastern) part of the Kiremt region and global tropical-subtropical sea surface temperature patterns, including the ENSO phenomenon.
Similar content being viewed by others
References
DO Adefolalu (1983) ArticleTitleRainfall patterns in coastal areas of Nigeria. Nigerian Geogr J 26 153–170
R Ananthakrishnan MK Soman (1988) ArticleTitleThe onset of the southwest monsoon over Kerala. J Climatol 8 283–296
JO Ayoade (1974) ArticleTitleA statistical analysis of rainfall over Nigeria. J Trop Geogr 29 11–23
NJ Bello (1997) ArticleTitleInvestigating the spatial pattern of the characteristics of the onset and cessation of the rains in Nigeria. Geogr J 43 113–123
Berkele T (1987) Food shortages, assessment and prediction: methods of the early warning system of Ethiopia, chap. 17. In: Planning for drought: toward a reduction of societal vulnerability (Wilhite DA, Easterling WE, Wood DA, eds). Boulder and London: Westview Press, pp 273–282
U Bhatt (1989) ArticleTitleCirculation regimes of rainfall anomalies in the African-South Asian Monsoon belt. J Climate 2 1133–1144 Occurrence Handle10.1175/1520-0442(1989)002<1133:CRORAI>2.0.CO;2
RW Burpee (1972) ArticleTitleThe origin and structure of easterly waves in the lower troposphere of North Africa. J Atmos Sci 29 77–90 Occurrence Handle10.1175/1520-0469(1972)029<0077:TOASOE>2.0.CO;2
TC Chen H van Loon (1987) ArticleTitleInterannual variation of the Tropical Easterly Jet. Mon Wea Rev 115 1739–1759 Occurrence Handle10.1175/1520-0493(1987)115<1739:IVOTTE>2.0.CO;2
GD Cook RG Heerdegen (2001) ArticleTitleSpatial variation in the duration of the rainy season in monsoonal Australia. Int J Climatol 21 1723–1732 Occurrence Handle10.1002/joc.704
Degefu W (1987) Some aspects of meteorological drought in Ethiopia, chap. 2. In: Drought and hunger in Africa (Glantz MH, ed). Cambridge University Press, pp 223–236
W Drosdowsky (1996) ArticleTitleVariability of the Australian summer monsoon at Darwin: 1957–1992. Mon Wea Rev 9 85–96
LM Druyan RD Koster (1989) ArticleTitleSources of Sahel precipitation for simulated drought and rainy seasons. J Climate 2 1438–1446 Occurrence Handle10.1175/1520-0442(1989)002<1438:SOSPFS>2.0.CO;2
L Eklundh P Pilesjö (1990) ArticleTitleRegionalization and spatial estimation of Ethiopian mean annual rainfall. Int J Climatol 10 473–494
AW Ellis EM Saffell TW Hawkins (2004) ArticleTitleA method for defining monsoon onset and demise in the southwestern USA. Int J Climatol 24 247–265 Occurrence Handle10.1002/joc.996
CK Folland TN Palmer DE Parker (1986) ArticleTitleSahel drought and worldwide sea temperatures, 1901–85. Nature 320 602–607 Occurrence Handle10.1038/320602a0
B Fontaine S Janicot (1992) ArticleTitleWind field coherence and its variation over West Africa. J Climate 5 512–524 Occurrence Handle10.1175/1520-0442(1992)005<0512:WFCAIV>2.0.CO;2
Giorgis DW (1987) Drought crisis management: the case of Ethiopia, chap. 32 In: Planning for drought: toward a reduction of societal vulnerability (Wilhite DA, Easterling WE, Wood DA, eds). Boulder and London: Westview Press, pp 519–523
T Gissila E Black DIF Grimes JM Slingo (2004) ArticleTitleSeasonal forecasting of the Ethiopian summer rains. Int J Climatol 24 1345–1358 Occurrence Handle10.1002/joc.1078
S Hastenrath (1991) Climate dynamics of the tropics. Kluwer Academic Publishers Dordrecht 488
S Hastenrath (2000) ArticleTitleInterannual and longer term variability of upper-air circulation over tropical Atlantic and West Africa in boreal summer. Int J Climatol 20 1415–1430 Occurrence Handle10.1002/1097-0088(200010)20:12<1415::AID-JOC550>3.0.CO;2-C
GJ Holland (1986) ArticleTitleInterannual variability of the Australian summer monsoon at Darwin: 1952–82. Mon Wea Rev 114 594–604 Occurrence Handle10.1175/1520-0493(1986)114<0594:IVOTAS>2.0.CO;2
IT Jolliffe DE Sarria-Dodd (1994) ArticleTitleEarly detection of the start of the wet season in tropical climates. Int J Climatol 14 71–76
PV Joseph JK Eischeid RJ Pyle (1994) ArticleTitleInterannual variability of the onset of the Indian monsoon and its association with atmospheric features, El Niño, and sea-surface temperature anomalies. J Climate 7 81–105 Occurrence Handle10.1175/1520-0442(1994)007<0081:IVOTOO>2.0.CO;2
E Kalnay et al. (1996) ArticleTitleThe NCEP/NCAR 40-year Reanalysis Project. Bull Amer Meteor Soc 77 437–471 Occurrence Handle10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2
M Kanamitsu TN Krishnamurti (1978) ArticleTitleNorthern Hemisphere subtropical circulations during drought and normal rainfall months. Mon Wea Rev 106 331–347 Occurrence Handle10.1175/1520-0493(1978)106<0331:NSTCDD>2.0.CO;2
TN Krishnamurti (1971) ArticleTitleObservational study of the tropical upper troposphere motion field during the Northern Hemisphere summer. J Appl Meteor 10 1066–1096 Occurrence Handle10.1175/1520-0450(1971)010<1066:OSOTTU>2.0.CO;2
PJ Lamb (1978a) ArticleTitleLarge-scale tropical Atlantic surface circulation patterns associated with Sub-saharan weather anomalies. Tellus 30 240–251
PJ Lamb (1978b) ArticleTitleCase studies of tropical Atlantic surface circulation patterns during recent Sub-Saharan weather anomalies: 1967 and 1968. Mon Wea Rev 106 482–491 Occurrence Handle10.1175/1520-0493(1978)106<0482:CSOTAS>2.0.CO;2
PJ Lamb RA Peppler (1992) ArticleTitleFurther case studies of tropical Atlantic surface atmospheric and oceanic patterns associated with Sub-Saharan drought. J Climate 5 476–488 Occurrence Handle10.1175/1520-0442(1992)005<0476:FCSOTA>2.0.CO;2
MA Lander CP Guard (1998) ArticleTitleA look at global tropical activity during 1995: contrasting high Atlantic activity with low activity in other basins. Mon Wea Rev 126 1163–1173 Occurrence Handle10.1175/1520-0493(1998)126<1163:ALAGTC>2.0.CO;2
CS Lee R Edson WM Gray (1989) ArticleTitleSome large scale characteristics associated with tropical cyclone development in the northern Indian Ocean during FGGE. Mon Wea Rev 117 407–426 Occurrence Handle10.1175/1520-0493(1989)117<0407:SLSCAW>2.0.CO;2
SM Loehrer TA Edmands JA Moore (1996) ArticleTitleTOGA COARE upper-air sounding data archive: development and quality control procedures. Bull Amer Meteor Soc 77 2651–2671 Occurrence Handle10.1175/1520-0477(1996)077<2651:TCUASD>2.0.CO;2
E Meze-Hausken (2000) ArticleTitleMigration caused by climate change: how vulnerable are people in dry-land areas? A case-study in Northern Ethiopia. Migration and Adaptation Strategies for Global Change 5 379–406 Occurrence Handle10.1023/A:1026570529614
DL Montroy MB Richman PJ Lamb (1998) ArticleTitleObserved nonlinearities of monthly teleconnections between tropical Pacific sea-surface temperature anomalies and central and eastern North American precipitation. J Climate 11 1812–1835 Occurrence Handle10.1175/1520-0442(1998)011<1812:ONOMTB>2.0.CO;2
CC Mutai MN Ward (2000) ArticleTitleEast African rainfall and tropical circulation/convection on intraseasonal to interannual timescales. J Climate 13 3915–3939 Occurrence Handle10.1175/1520-0442(2000)013<3915:EARATT>2.0.CO;2
CC Mutai MN Ward AW Colman (1998) ArticleTitleTowards the prediction of East African short rains based on SST-atmosphere coupling. Int J Climatol 19 975–997 Occurrence Handle10.1002/(SICI)1097-0088(199807)18:9<975::AID-JOC259>3.3.CO;2-L
TO Odekunle (2004) ArticleTitleRainfall and the length of the growing season in Nigeria. Int J Climatol 24 467–479 Occurrence Handle10.1002/joc.1012
EO Oladipo JD Kyari (1993) ArticleTitleFluctuations in the onset, termination, and length of the growing season in northern Nigeria. Theor Appl Climatol 47 241–250 Occurrence Handle10.1007/BF00866245
RA Peppler PJ Lamb (1989) ArticleTitleTropospheric static stability and central North American growing season rainfall. Mon Wea Rev 117 1156–1180 Occurrence Handle10.1175/1520-0493(1989)117<1156:TSSACN>2.0.CO;2
Raman CRV (1974) Analysis of commencement of monsoon rains over Maharashtra State for agricultural planning. Prepubl. Scientific Report No. 216, India Meteorological Department
AB Shaw (1987) ArticleTitleAn analysis of the rainfall regimes of the coastal region of Guyana. J Climatol 7 291–302
M Shinoda R Kawamura (1994) ArticleTitleTropical rainbelt, circulation and sea surface temperatures associated with the Sahel rainfall trend. J Meteor Soc Japan 72 341–357
MVK Sivakumar (1992) ArticleTitleEmpirical analysis of dry-spells for agricultural applications in West Africa. J Climate 5 532–539 Occurrence Handle10.1175/1520-0442(1992)005<0532:EAODSF>2.0.CO;2
MVK Sivakumar A Maidoukia RD Stern (1993) Agroclimatology of West Africa, 2nd ed. ICRISAT Niamey 108
TM Smith RW Reynolds RE Livezey DC Stokes (1996) ArticleTitleReconstruction of historical sea-surface temperature using empirical orthogonal functions. J Climate 9 1403–1420 Occurrence Handle10.1175/1520-0442(1996)009<1403:ROHSST>2.0.CO;2
RD Stern MD Dennett DJ Garbutt (1981) ArticleTitleThe start of the rains in West Africa. J Climatol 1 59–65
Tadesse T (1994) The influence of the Arabian Sea storms/depressions over the Ethiopian weather. Proc Int. Conf. on monsoon variability and prediction, WCRP-84 and WMO/TD No. 619, World Meteorological Organization, Geneva, pp 228–236
A Tarhule PJ Lamb (2003) ArticleTitleClimate research and seasonal forecasting for West Africans: perceptions, disseminations, and use? Bull Amer Meteor Soc 84 1741–1759 Occurrence Handle10.1175/BAMS-84-12-1741
WM Venables BD Ripley (1997) Statistics and computing: modern applied statistis with S-plus. Springer New York 548
MN Ward (1998) ArticleTitleDiagnosis and short lead-time prediction of summer rainfall in tropical North Africa at interannual and multidecadal timescales. J Climate 11 3167–3191 Occurrence Handle10.1175/1520-0442(1998)011<3167:DASLTP>2.0.CO;2
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Segele, Z., Lamb, P. Characterization and variability of Kiremt rainy season over Ethiopia. Meteorol. Atmos. Phys. 89, 153–180 (2005). https://doi.org/10.1007/s00703-005-0127-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00703-005-0127-x