Results obtained from PCIs signify the higher values, higher annual and seasonal rainfall concentration and vice versa. The focus of this study is to investigate the spatiotemporal variability and trends in rainfall and temperature in Alwero watershed in the western part of Ethiopia using a dense network of 4 4 km gridded data (558 points) reconstructed from weather stations and meteorological satellite records which spatially covers the watershed. This is probably due to the fluctuation and variability of the seasonal and inter-annual rainfall pattern of the Beressa watershed during the last few decades, as indicated in Table3, which is similar to other studies (Muhire & Ahmed 2015; Zhao et al. The coefficient of variation is higher during the rainfall in the bega and belg seasons than the rainy season (kiremit rainfall season), as shown in Table2. Most of the studies about rainfall and temperature characteristics are limited by short-term and long-term time series available for most parts of the regions. At the annual scale, maximum and minimum temperatures significantly increased in over 33% of the Basin at a rate of 0.1 and 0.15 C per decade, respectively; however, the western part (12%) of the Basin experienced declining trends on annual and seasonal timescales. 2012). During this period,the Northeast Trade Winds carrying non-moisture-laden dominates the region. The period from March to May, as often happens in Ethiopia, is the warmest of the year, albeit by a few degrees. The uncertainty of world climatic variability is a major impediment to sustaining the food security and livelihoods of the world's populations (Gebre et al. 2013; Irannezhad et al. The rainfall and temperature daily records over 35 years (19802014) for the Beressa watershed were obtained from the National Meteorological Service Agency of Ethiopia from seven stations; hence rainfall on a monthly, seasonal and annual basis were derived from the daily data. This study involves the observation of climatic variables, i.e. Thus temperature, as it is affected by altitude, decreasestowards the interior highlands. In general, these future projections point towards increases in summertime temperatures and modifications in precipitation across both regions. The location of Ethiopia at close proximity to equator, a zone of maximum insolation,resulted for every part of the country to experience overhead sun twice a year. 2005). Spatiotemporal Distribution of RainfallRainfall system in Ethiopia is characterized by complexities. Such studies ignored the localized trends of rainfall and temperature, particularly in most highlands of Ethiopia. The region is divided in to dry and wet summer rainfall regions.Hence, the wet corresponds to the area having rainfall of 1,000 mm or more. Seasonal or Temporal VariabilitiesWhat winds bring summer rainfall for Ethiopian highlands?The rainfall is highly variable both in amount and distribution across regions and seasons.The seasonal and annual rainfall variations are results of the macro-scale pressure systemsand monsoon flows which are related to the changes in the pressure systems discussed in theprevious sections of this chapter. After visual identification of the outliers, each of the values was obtained using a normal ratio technique. Climatic variability in the past has been increasing and from the trends suggested in different studies, may further increase in the near future, putting urgent emphasis on how the community perceives the extent of climate change in order to design coping and adaptation strategies (Belay et al. In the study area, June is the sowing period for barley and wheat crops. For most developing countries of the world, agriculture is the basis of the economy. RH trends along the coast have a weak negative bias due to neglect of the ocean's moderating influence. The mean annual temperature varied between 13 and 15.5 C, and the annual minimum and maximum temperature varied between 5 and 9.5 C, respectively. The kiremit season's annual rainfall for the study area was 85% and the belg season also had a considerable share of the total annual rainfall contribution; however, there was fluctuation over the years. A climate impact study in the Upper Blue Nile, North American Climate in CMIP5 Experiments. Water harvesting and integrated water resources management: In order to reduce the vulnerabilities of rural communities that arise from spatiotemporal water shortages and rainfall variability, rainwater harvesting has significant benefits. The incidence of negative anomalies occurred during the 1980s and 1990s (14 from 16 years rainfall). The correlation between rainfall during the months of MaySeptember and crops has a positive relationship, except in the cases of beans, peas and chickpeas, which are inversely correlated with rainfall during the month of June. The aim of this study was to evaluate climate variability and characterize the spatiotemporal distribution of meteorological droughts using a merged satellite-gauge rainfall across the major agroecological zones (AEZs) of the rift valley lakes basin. Because of the rainfall-dependent farming practice, farmers are always worried about the duration and intensity of rainfall. Assessing the long-term spatiotemporal rainfall distribution pattern is the most significant component in the climate analysis of a given country, more specifically at the local and regional levels where the effect of climate change is worse. The spatial distribution of temperature in Ethiopia is primarily determined by altitude andlatitude. Is it warming or cooling? Geography: Definition, Scope and Themes, 1.2. . Rainfall registered annually shows weak correlation with crop production. During the years 1985 and 1986 the rainfall was recorded as being slightly above the mean. The Geologic Processes: Endogenic and Exogenic Forces, 2.3. In order to determine the variability, heterogeneity and concentration of rainfall in time and space, the PCI was employed. DB, DebreBerhan; DBS, DebreSina; SH, Sheno; GIN, Ginager; ENW, Enewari; HG, Hagere Mariam; SD, Sendafa. Additionally, serial correlation was tested. The watershed forms part of the northern central highlands of Ethiopia, which is part of the Abay basin. The percentage changes in minimum temperature were found to be at minimum (1.90%) and maximum (52.40%) in GIN and DBS stations, respectively. In autumn the ITCZ shiftstowards the equator weakening the equatorial westerlies. 2002; Suryavanshi et al. Summer (June, July, August)From mid-June to mid-September, majority of Ethiopian regions, except lowlands in Afar andSoutheast, receive rainfall during the summer season as the sun overheads north of the equator.High pressure cells develop on the Atlantic and Indian Oceans around the tropic of CapricornAlthough, the Atlantic contributes a lot, the Indian Oceans is also sources of rainfall. Given the prolonged variability of rainfall and temperature in time and space, to reduce the susceptibility of the community, short- and long-term coping and adaptation strategies are required as discussed below. Air temperature estimation using remote sensing satellite provides a new way of conducting studies in the field of climate change study. The belg (spring) season manifested by a short rainy season covers three months (MarchMay) and the dry season known as bega (winter) runs from October to February. For example, months from March to June in Ethiopiahave records of highest temperatures. 2013). 2015; Pingale et al. Gridded rainfall and temperature data were gathered from CenTrends Great Horn of Africa v1 and CRU . Correlation between crop production, and rainfall and temperature (19972014). 2005; Batisani & Yarnal 2010; Randell & Gray 2016). Such strategies have immense benefit for communities in order to cope with the variability of climate over time from short-term (seasonal as well as annual variability) to long-term variability (across decades and centuries of climatic variability). Additionally, studies of rainfall and temperature variations in larger areas would in general be of little use for local level agricultural production (Gebre et al. Specifically, we examine and evaluate multi-model, multi-scenario climate change projections and seven extreme temperature and precipitation indices over the eastern Himalaya (EH) and western Himalaya-Karakoram (WH) regions for the 21st century. As presented in Table3, the Sen's slope estimator indicates an upward trend in four stations and a downward trend in three stations for annual rainfall. 2016). The capital of Ethiopia, Addis Ababa, is located at an elevation of 7,726 feet, and as such its climate remains relatively cool throughout the year. Conversely, low flow conditions will intensify during the warm months. From Figure3, it is confirmed that the maximum temperature has continuously increased by about 1.10 C, whereas the minimum temperature has increased by about 0.70 C. Rainfall and temperature trends detection is vital for water resources management and decision support systems in agro-hydrology. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Climate Change 2007 Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Fourth Assessment Report of the IPCC, Climate Change 2007 the Physical Science Basis: Working Group I Contribution to the Fourth Assessment Report of the IPCC, IPCC, 2013: Climate Change 2013: the Physical Science Basis. Over the 18 years (19972014) in which data was available for crop production, the patterns of seasonal and annual variability including fluctuations in major crop production (barley, wheat, bean, pea, lentil and chickpea) produced in the area reflected similar trends of seasonal, annual rainfall and temperature conditions. 2013; Muhire & Ahmed 2015). During this time, thecentral highlands, southeastern highlands and lowlands receives rainfall as the south easterliesbring moist winds. Multi-model average (MMA) projections additionally indicate continued trends towards more extreme conditions consistent with a warmer, wetter climate. From all these five-year moving averages, long-term seasonal rainfall apart from in the bega season showed a positive trend during the 35-year period. Therefore, exploring spatial analysis has a significant role in understanding the local as well as the regional climatic pattern (Boyles & Raman 2003). The problem is high in developing countries, particularly sub-Saharan countries in which the majority of the population live on rainfed agriculture. Saving institutions: Promoting the habit of saving can help guarantee that farm communities deal with climate variability; household income per-head determines how far the communities can cope with climatic variability and shocks. Rock and Mineral Resources of Ethiopia, CHAPTER THREE THE TOPOGRAPHY OF ETHIOPIA AND THE HORN, 3.2. A numerical experiment where the values of T dew are altered to compensate for the RH error suggests that eliminating the atmospheric moisture bias could, in and of itself, decrease runoff up to 14 % in high-altitude regions east of the Sierra Nevada and Cascades, and reduce estimated Colorado River runoff at Lees Ferry up to 4 % by the end of the century. Continuously increasing temperature, together with the variability and fluctuation of seasonal and inter-annual rainfall is a root cause for the decrease and fluctuation of crop production. However, it hasno significant coverage compared to other seasons. The annual minimum and maximum rainfall is 698.5 and 1083.3 mm, respectively. 2010 ). Spatiotemporal Distribution of TemperatureAltitude is an important element in determining temperature of Ethiopia and the Horn. Enter the email address you signed up with and we'll email you a reset link. The line connecting the fixed average is known as averagely moving. During the winter season, the Redsea escarpments and some parts of the Afar region receive their main rain. Understanding projections of extreme precipitation is part of a resilient response to its impacts. The guidelines for interpretation are presented in Table1. The average rainfallvaries from less than 500 to 1,000 mm.iv. The convergence of Northeast Trade winds and the Equatorial Westerlies forms theITCZ, which is a low-pressure zone.The inter-annual oscillation of the surface position of theITCZ causes a variation in the Wind flow patterns over Ethiopia and the Horn. Our analyses demonstrate that there will be an increase in precipitation intensity and a decrease in frequency over Zambia from the middle of the 21st century. Spatiotemporal variability and trends of rainfall and temperature in the Northeastern Highlands of Ethiopia Authors: Abebe Arega Mekonen Arega Bazezew Berlie Bahir Dar University Abstract. The magnitude of the linear trends is estimated using the Sen's slope estimator and Mann-Kendall's test is performed to check the statistical significance of the trends. The mean annual rainfall of the basin spatially varies from 417 to 1012 mm, with a noticeable temporal variation at a monthly time scale. This It is a rainfall region in the southwestern partof the country. Time series of all MMA precipitation indices exhibit significant increasing trends over the 19012099 period.
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