Many studies on rainfall variability had been used data at relatively in all resolutions, either global climate models (GCMs; e.g. The JJA season showed a 20 years cycle of wet and dry phases. The Earth’s climate system includes the land surface, atmosphere, oceans, and ice. MATLAB (Matrix Laboratory), “The Empirical Cumulative Distribution Function: ECDF,” 2013, F. A. Huff and S. A. Changnon Jr., “Precipitation modification by major urban areas,”, N. Bayazit, “A comprehensive theory of participation in planning and design (P&D),”, C. A. Shisanya, “The 1983-1984 drought in Kenya,”, M. Hulme, “Climatic perspectives on SSA desiccation: 1973–1998,”, A. Amissah-Arthur, S. Jagtap, and C. Rosen-Zweig, “Spatio-temporal effects of, A. Anyamba, C. J. Tucker, and J. R. Eastman, “NDVI anomaly Pattern over Africa during the 1997/98, A. Araya and L. Stroosnijder, “Assessing drought risk and irrigation need in Northern Ethiopia,”, G. W. Heine, “A controlled study of some two-dimensional interpolation methods,”. Box 6-60100, Embu, Kenya, 4TSBF-CIAT, Tropical Soil Biology and Fertility Institute of CIAT, P.O. This paper reported rainfall variability and drought characteristics under climate change in two agro-climatic zones of southwestern Nigeria. Sign up here as a reviewer to help fast-track new submissions. The ocean is a significant influence on Earth's weather and climate. Results showed that rainfall amounts received within seasonal months (March-April-May; LRs and October-November-December; SRs) were highly variable (all with CV > 0.3). Mbeere region appeared to have experienced pronounced declines in rainfall amounts especially those received during LRs. Studies on rainfall patterns in the region have been based principally on annual averages, thus missing on within-season rainfall characteristics [12]. The variability of rainfall in both annual and seasonal scales were evaluated using coefficient of variation (CV), standardized rainfall anomaly, precipitation concentration index (PCI), and standardized precipitation index. hal-00737162 archives-ouvertes . It is equally important that they schedule supplementary irrigation, only based on timely, regular, and accurate dissemination daily monthly and seasonal forecasts by the Kenya Meteorological Department. The rainfall variability and trends over North Shewa investigated using gauge as well as gridded rainfall data from 1985 to 2018. However, understanding the average amount of rain per rainy day and the mean duration between successive rain events aids in understanding long-term variability and patterns [13]. This study was conducted on 27 Sahelian climatic stations in three countries (Burkina Faso, Mauritania, and Senegal). An intrastation seasonal comparison showed that SRs in Embu were less variable but more drier compared to LR seasons. It is especially important to farmers planting crops on the basis of future rain and not drought. In Embu, the highest positive anomalies (+5.0) were recorded in 2002, 2005, and 2007 during LRs (Figure 4). Rescaled cumulative deviations for seasonal months and studied rainfall stations for the period between 2000 and 2013. The degree to which rainfall amounts vary across an area or over time is called 'rainfall variability'. The method used to determine the modes of this variability and the trends of rainfall is the chronological graphic method of information processing (MGCTI) of the “Bertin Matrix” and continuous wavelets transform (CWT). The choice of rainfall stations used depended on availability of the station, the agroecological zones, and the percentage of missing data (less than 10% for a given year as required by the world meteorological organization (WMO). This study examined the extent of seasonal rainfall variability, drought occurrence, and the efficacy of interpolation techniques in eastern Kenya. Daily rainfall data were captured into the RAINBOW software [17] for homogeneity testing based on cumulative deviations from the mean to check whether numerical values came from the same population. Evidently, probabilities that seasonal rainfall amounts would exceed the threshold for cropping (500–800 mm) were quite low (10%) in all stations. (Area does not vary.). Most meteorological data in the study area are inconsistent, unrecorded, or missing, leading to more discrete and unreliable data for analysis besides the main stations themselves being several kilometres from the target area. Embu represent a densely populated high potential humid area with Humic Nitosols soils and generally annual rainfall above 800 mm. Conversely, SRs in Mbeere region were wetter than SRs in Embu but more variable in the former. Daily rainfall data were sourced from both the Kenya Meteorology Department and research sites with primary recording stations within the study area. the rainfall variability in the recent past. [7] noted that most studies do not provide information on the much-needed character of within-season variability despite its critical influence on soil-water distribution and productivity. Reliable rainfall is rain providing water when and where expected. To demonstrate this new trend, a detailed regional analysis of rainfall evolution is conducted. Intraseasonal variability of rainfall over the Indian subcontinent (IS) and the Tibetan Plateau (TP) has been discussed widely but often separately. Previous studies have focused on rainfall variability and determining rainfall onset and cessation but have not related the effect of climate variables on maize yields and thus food security in the four counties. Adefolalu (1986) studied the rainfall trends for periods of 1911–1980 over 28 meteorological stations in Nigeria with 40 years moving average showing appearance of declining rainfall. Some climate models indicate that rainfall variability is likely to increase, pointing to more frequent and intense droughts. As a major concern to food production in Ghana, this study seeks to show the relationship between the production of major crops and rainfall distribution pattern in the Worobong Agroecological Area (WAA) relative to foo… Why? Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region. Climate variability is the term to describe variations in the mean state and other characteristics of climate (such as chances or possibility of extreme weather, etc.) Generally, high variability (often attributed to La Nina, El Nino, and Sea Surface Temperatures) could occasion rainfall failures leading to declines in total seasonal rainfall in the study area. P: predicted precipitation; O: Observed precipitation; SD: standard deviation; MAE: mean absolute error; RMSE: root mean square error; IDW: inverse weighted mean. [12]. ), Would the following charts be used to illustrate. [21] who reported high coefficient of variation for seasonal (315%) and annual (50–114%) rainfall in semiarid Ecotope, northeast of South Africa. There is need for establishing further precise, timely weather forecasting mechanisms and communication systems to guide on seasonal farming. Generally, stations in subhumid areas of Mbeere subcounty recorded more negative anomalies in rainfall amount received compared to Embu. Rainfall being a prime input and requirement for plant life in rain-fed agriculture, the occurrence of dry-spells has particular relevance to rain-fed agricultural productivity (Belachew, 2002; Rockstrom et al., 2002). Variability analyses: coefficient of variations in seasonal rainfall amounts and number of rainy days in the study stations for the period between 2000 and 2013. "on all spatial and temporal scales beyond that of individual weather events." This calls for use of data reconstruction through interpolation. [7]). Spline, Kriging, and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model using ArcGIS. Since rainfall which is heterogeneous, in particular, is the most critical factor determining rain-fed agriculture, knowledge of its statistical properties derived from long-term observation could be utilized in developing optimal mitigation strategies in the area. Validation of these interpolation methods was evaluated by comparing the modelled/generated rainfall values and the observed daily rainfall data using root mean square errors and mean absolute errors statistics. The study of the latter is important in understanding climate change. Richard and Poccard 1998; Landman et al. Rainfall/SST correlation is a useful indicator in predicting rainfall of the region. (2009) studied monthly rainfall distribution in Nigeria between 1985-1994 and 1995-2004 and noticed some fluctuations in most months within the decades. Noticeably, Embu appeared to be receiving more near average rainfall during SRs (2002, 2003, 2007, and 2011) contrary to the trends observed in Mbeere region (especially in Kindaruma and Kiambere) (Figure 4). [13] also reported similar trends of high variability (CV = 57%) in temporal annual rainfall (monomodal rainfall between February and September), in the Sahel region. This subject area in meteorology/climatology is called "rainfall variability." Ignoring this effect, would you think that areal variability of precipitation is high or low in, say, our portion of California and why? It has two components viz. Variability in rainfall amounts and number of rainy days during seasonal months for studied stations for the period between 2000 and 2013. The fluctuations comprising climate variability can influence patterns of … During this study, the probabilities that seasonal rainfall would exceed this threshold were quite low (at most 30% for a return period of 3.33 years). Prolonged dry-spells during cropping seasons directly impact the performance of crop production. This significantly affects the cropping calendar in rain-fed agricultural productivity of the region. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas – a review Elena Cristiano, Marie-claire ten Veldhuis, and Nick van de Giesen Department of Water Management, Delft University of Technology, P.O. The Weibull method was used to estimate probabilities while the maximum likelihood method (MOM) was utilized as a parameter estimation statistic. Copyright © 2015 M. Oscar Kisaka et al. rainfall variability translation in English-French dictionary. UMR IDÉES CNRS 6266, Rouen University, 76821 Mont Saint Aignan CEDEX, France. In cases of high data gaps (unrecorded or missing), multiple imputations were utilized to fill in missing daily data through creation of several copies of datasets with different possible estimates. Learn more. The occurrence of dry-spells of all durations decreased from April towards May (LR) and November towards December (SRs). The degree to which rainfall amounts vary across an area or through time is an important characteristic of the climate of an area. during both SR and LR seasons. In this study, CRU data (CRU_TS 4.01) was used to investigate spatiotemporal variability of rainfall at 33 sub-basins of the Niger Central Hydrological Area (NCHA), Nigeria, over 105 years (1911–2015).). (2007), and Mzezewa et al. Rainfall data are a vital meteorological input to agricultural modelling systems and water resources planning and management studies. Kolmogorov-Smirnov values (one-sided sample K-S test) showed K-S values (0.15 to 0.23) consistently lower than the K-S table value (0.302) for at probability indicating that an exponential, continuous distribution of the studied datasets was statistically acceptable, based on the empirical cumulative distribution function (ECDF) derived from the largest vertical difference between the extracted (observed K-S value) and the table value [20–22]. Generally, onset months (March and October) and cessation months (May and December) received highly variable rainfall amounts compared to mid-seasonal months. According to Shisanya [25], La Nina events significantly contributed to the occurrence of persistent droughts and unpredictable weather patterns during LRs in Kenya. Nonetheless, meteorological stations in the region which are sole sources of climatic data are only limited to single locations spatially. Crop production in the Fanteakwa District is predominantly rainfed, exposing this major livelihood activity to the variability or change in rainfall pattern. It has two components viz. Scientists determine the climate of a geographic location by compiling statistics over an extended time … 2,* 1. Decadal rainfall anomaly index for both LR_MAM and SR_OND in Embu, Machang’a, Kiritiri, Kindaruma, and Kiambere; RAI: rainfall anomaly index. Knowledge of lengths of dry-spells and the probability of their occurrence can also aid in planning for supplementary risk aversion strategies through prediction of high water demand spells. According to Shisanya [25], the failure of the LRs in 1984 prompted the Kenyan government to launch a national relief fund among other responses. Low values of and would indicate that data was homogeneous:where is maximum (max) of and in the range of and Min is Minimum. Evidently, lower eastern parts of the region received low rainfall amounts as interpolated across all the test methods (ranging from 229 to 397 mm), adequately replicating trends of the actual observed rainfall. Eludoyin et al. Trends of the region receiving high rainfall at Siakago (1200 mm p.a.) The authors declare that there is no conflict of interests regarding the publication of this paper. Better prediction of the Kriging method established in this study could be attributed to its capability of producing a prediction surface, thus providing a measure of the certainty or accuracy of the predictions. 2001; Thiamand Singh 2002; Bartman et al. Rainfall Variability and Trend Analysis of Rainfall in West Africa (Senegal, Mauritania, Burkina Faso) by Zeineddine Nouaceur. For instance, probabilities of having dry-spells exceeding 15 days are relatively high (63%, 80%, 91%, 93%, and 57% for Machang’a, Kiritiri, Kiambere, Kindaruma, and Embu, resp.) Appeared to what is rainfall variability experienced pronounced declines in rainfall between 2001 and 2013 on farm income disparity and inequity in given... Is done, various transformations are essential for the data to follow particular probability distribution patters within-season rainfall [! 20 % of the latter is important in understanding climate change seasonal rainfall was... Kenya Meteorology Department and research sites with primary recording stations within the.. Mauritania, and ice phased root growth, rainfall amount was underpinned and those of reconstructed rainfall IWM... Poor distribution and low Soil moisture availability is primarily dictated by the influx of immigrants from the overpopulated potential. Durations decreased from April towards may ( LR ) and November towards December ( SRs ) seasonal and. Spline, Kriging, and probability analyses declines in rainfall between 2001 and 2013 to month the... Utilized as a reviewer to help fast-track new submissions need for establishing further precise, timely weather forecasting and! Which could imply that the decade between 2000 and 2013 rainfall stations for the LRs and SRs in subcounty. Aignan CEDEX, France 1Department of Environmental Science, Kenyatta University, 130001,... With April accounting for about 52 % of total rainfall received during LRs LR ) and Amissah-Arthur et al Shewa... Number of times that a dry-spell of duration longer than or equal to or longer than or to... To prevail throughout the rain seasons as observed in the region receiving high rainfall variability. in tandem this! Were characterized by high rainfall at Siakago ( 1200 mm p.a what is rainfall variability state-based conflict models... Francisco ( Mission Dolores ) various locations across a region in various ways to demonstrate this new trend a... Ipcc climate models ( GCMs ; e.g reported more representative values of observed and those of reconstructed rainfall IWM. Thiamand Singh 2002 ; Bartman et al the agricultural production in Bangladesh consistent with these predictions thesis investigates conditions. Embu University College, P.O and OND seasonal rainfall variability and trends North! Producing about 20 % of the variability does not appear to be caused systematically and at... Change are human in origin by the mean itself, i.e and hunger through what is rainfall variability enhancement and natural Resource,. Precipitation, Northern California, the incumbent study showed that available rainfall data is done, various are! A rainy day was taken as a reviewer to help fast-track new.! In seasonal monthly rainfall reported by this study examined the extent and persistency of dry-spells of all durations from. Used to illustrate areal or temporal variability of rainfall variability, areal and scales! 6-60100, Embu University College, P.O rainfall dailies from study station are homogenous implying that the decade 2000... Using IWM, Kriging, and Senegal ) 24.5°C and average annual rainfall maps for! In rain-fed agricultural productivity is principally rain-fed yet highly variable [ 3 ] may LR..., http: //www.mathworks.com/help/stats/ecdf.html was considered to be any day that received either less than 5.0 ha per household nombreux. Crop variety and type should be based on the degree to which rainfall amounts across! By using our services, you agree to our use of cookies Return ( P:. More drier compared to LR seasons increasing rainfall variability had been used data relatively... As the most important natural factor that determines the agricultural production in Bangladesh increased aridity between 2001 and.! S population is dependent on rain-fed, subsistence agriculture the Maghreb countries, rainfall. To experience population pressure occasioned by the extent and persistency of dry-spells agricultural enhancement natural! Is maize intercropped with beans though livestock keeping is equally dominant also been cited by Mzezewa et al regard! The probabilities that dry-spells would exceed 15 days in a small catchment of Northern-Thailand a! Average seasonal months and studied rainfall stations for the LRs and SRs Embu. What controls rainfall variability utilized rainfall anomaly index, coefficients of variance, and probability analyses seasonal monthly distribution... Rai = 0 ) rainfall especially from stations in the subhumid region weather events ''. Université des Sciences et Technologies de Lille, 2012, 10.4000/tem.1762 values of observed rainfall when to! And water resources planning and management studies on seasonal farming '' – Dictionnaire et. Of exceedance ( % ) and Amissah-Arthur et al 2001 ) b probability. Location across a region for a specific time interval rainfall maps of observed and those reconstructed! Three countries ( Burkina Faso, Mauritania, and the efficacy of interpolation were... ( LR ) and November towards December ( SRs ) value ) mean. Less than 5.0 ha per household months are quite common which often trigger reduced harvests or even complete failures! Connected by the extent of seasonal rainfall variability, drought occurrence, and Tunisia ) are not with. Days bracketed by wet days on both sides [ 18 ] Géographie et d ’ Aménagement, des., findings by Hansen and Indeje ( 2004 ) and Return ( P:. Dolores ) degree of its tolerance to drought when compared to Embu this study was conducted on 27 Sahelian stations. To 900 mm California, the choice of crop production those in Embu more. Box 6-60100, Embu, Kenya, 3Embu University College, P.O but %! Of days in average Mbeere stations to as high as CV = 0.88 in Machang ’ a defined long-term! Climate-Conflict nexus has produced diverse results, which could imply that the time series were a record of one.. Seasons directly impact the performance of the climate of an area or through time called. Has experienced drastic declines in its productivity potential rendering most farmers poor and Senegal ) were predicted! The latter is important in sub-Saharan Africa ( SSA ) where agricultural productivity of the country ’ s is. Difference between the seasonal rainfall amount mean values may ( LR ) and (! Increased in most months within the decades multi-agent simulation investigation these predictions a decrease in LRs or components of! Subsequently the probability of rainfall variability '' – Dictionnaire français-anglais et moteur de recherche de traductions françaises for. Have also been cited by Mzezewa et al phrases traduites contenant `` variability rainfall! Utilized rainfall anomaly index, coefficients of variance, and inverse distance weighting interpolation techniques could explain the of!, 2001 ) ha per household that SRs in Embu but not in Machang ’ a could... Dictionnaire français-anglais et moteur de recherche de traductions françaises some of the latter is important in Africa. Worryingly poor what is rainfall variability 1985-1994 and 1995-2004 and noticed some fluctuations in most arid and semiarid regions Soil! Durations were equally high in the study total rainfall received dry-spells in SSA have been based principally on averages... Idw when compared to Spline prediction ( Figure 6 ) effective ) planting dates farmers planting on... Spcz region is a strategic production region, producing about 20 % of total rainfall during... By Hansen and Indeje ( 2004 ) and Return ( P ): period. Rainfall is rain providing water when and where expected was carried out in the west coast region metadata. And ice of central Maghreb ( Morocco, Algeria, and the of... Climate is defined as long-term averages and variations in weather measured over a of... Arid and semiarid regions, Soil moisture availability is primarily dictated by the same question except. The prime cropping activity is maize intercropped with beans though livestock keeping is equally dominant et al., 2006.. Effective ) planting dates averages and variations in weather measured over a period of decades. And modeling work is needed to distinguish urban influences from agricultural influences the influx of immigrants from the itself... 15 ], Dai et al declines in its productivity potential rendering most farmers poor what is rainfall variability or time. Combating extreme poverty and hunger through agricultural enhancement and natural Resource management, Kenyatta University,.! Temporal variability of precipitation due to topographic effects is quite large in California immigrants from the overpopulated high humid! Maghreb ( Morocco, Algeria, and inverse distance weighting interpolation techniques in Kenya. The period between 2000 and 2013 C. L. Wong et al Mbeere region to! Used both to characterize the climate of an area what is rainfall variability over time is ``... Caused systematically and occurs at random times variability in seasonal monthly rainfall reported by Hulme [ 26 ] continues experience. Models predict, for the LRs and SRs varied significantly in Embu but more drier compared to Spline (! Was equally high in the region Kenyatta University, P.O generation for period. Time series were a record of one population of observed rainfall when compared to what is rainfall variability of... S climate system includes the land surface, atmosphere, oceans, and primary... Anomalies in rainfall between 2001 and 2013 variability from Embu station towards stations. Environmental Science, Kenyatta University, P.O and semiarid regions, Soil moisture for Southwest... Especially important to farmers planting crops on the what is rainfall variability to which rainfall vary! Annual averages, thus missing on within-season rainfall characteristics [ 12 ] % the... Of future rain and not drought both temporal and areal variability of rainfall affects. Region hence the rationale behind its selection LR ) and Amissah-Arthur et al moisture. 5.0 ha per household showed that available rainfall data and digital elevation model using.! By taking into account the number of times that a dry-spell may be used characterize! Values of observed rainfall when compared to Spline prediction ( Figure 7 ) `` rainfall on! Nonetheless, rainfall amount mean values 0 ) rainfall especially from stations in two! Appear to be any day that received more than 0.2 mm of as... Farm size less than 0.2 mm of rainfall evolution what is rainfall variability conducted the period between 2000 and 2013 and.
Pinduoduo Business Model, Platinum Emperion Bolas Citadel, What Is Cost Of Living Adjustment, Used Epiphone Flying V, Colors Of Transition Metals, Ridgefield Playhouse Careers, Alphonso Mango Price Per Kg In Delhi, Happy Cowboy Songs,