| Dr. Joseph M Ininda Publications |
| 1 | 9999 | Simulation Of The Impact Of Deforestation On Rainfall In The Lake Victoria Basin.
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Over the past four decades, Lake Victoria basin has experienced drastic environmental changes on account of both natural and anthropogenic factors. The natural factors include prolonged droughts and the recent emergence of water hyacith in the lake, while anthropogenic factors include the deforestation rates, poor agricultural practices, and destruction of critical wetlands. This study examines the potential impact of deforastation on rainfall over the lake basin. To assess the potential impact of deforestation on rainfall over the region, the General Circulation Model (GCM) ECHAM5 was applied. ECHAM5 was used to predict the possible impact of land cover and land use changes on rainfall using land cover and land use scenarios based on the integrated model to Assess Global Environment (IMAGE). The projected vegetation cover for 2050 was used to model the impact of deforestation, which indicated a general decrease in the canopy. The results from the model indicated a decrease in rainfall over many parts, although some areas showed increased rainfall. From the study we conclude that while deforestation has an impact on climate, there seem to be a complex interaction between forest and the rainfall generation mechanism. |
| 2 | 9999 | Wet Periods Along The East Africa Coast And The Extreme Wet Spell Event Of October 1997
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| 3 | 2012 | Linkages Between Global Sea Surface Temperatures And Decadal Rainfall Variability Over Eastern Africa Region
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Heriot-Watt University, Edinburgh, UK. 256p. |
| 4 | 2010 | Spatial And Temporal Rainfall Characteristics Over Seychelles
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ABSTRACT
While Seychelles lies close to the Equator, it experiences only one
rainy season. The rainfall characteristics over this region is evident from the
Satellite observations which show that during most part of the year the active
clouds are concentrated to the eastern sector of the equatorial Indian Ocean
and Seychelles comes under active weather only during southern hemisphere
summer. The main objective of this study was to therefore investigate the spatial
and temporal characteristics of rainfall over Seychelles during the rainy
season. The specific objectives included demarcating Seychelles into rainfall
homogeneous zones, identify the rainfall season, determine the onset and cessation
of the rainy season. The data used in the study were the daily and
monthly rainfall over Seychelles for the period 1972 to 2006 and NCEP reanalysis
data. The methods used to analyze these data were Principal Component
Analysis (PCA), time series analysis, pentad and cumulative curves.
The results from PCA analyses showed that Seychelles may be divided
into four rainfall homogeneous zones. The study also shown that the rainfall
season occur between November and March. January was observed to be the
peak rainfall month, while July has the lowest amount of rainfall. The onset
and cessation of the rainy season occur in the month of November and March
respectively. Analysis of the low level flow showed the Near Equatorial
Trough (NET) is the main system influencing rainfall over the Seychelles region.
During the time of maximum rainfall in January, the Inter-Tropical Convergent
Zone (ITCZ) lies far to the south of the country |
| 5 | 2008 | Towards Improvement Of Seasonal Rainfall Forecasting Through Model Output Statistics (Mos) Downscaling Of Echam Forecasts Over Tanzania
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Many economic activities such as agriculture and hydroelectric power generation are dependent on the availability of water. The main source of water in Tanzania is rainfall. The seasonal rainfall over Tanzania is highly variable both in time and space. Hence there is need for a forecasting model. The main objective of the study was towards improvement of seasonal rainfall forecasting through model output statistics (MOS) down scaling of the ECHAM forecast over Tanzania. ECHAM is a numerical weather prediction model developed at the European Centre for Medium Range Weather Forecasting, that has a comprehensive parameterization package developed at Hamburg. The data used in the study consists of monthly rainfall for 15 stations over Tanzania and wind and rainfall output from ECHAM for the period 1971-2004. The observed data was first subjected to quality control to ensure that it was homogenous and consistent. The ECHAM was forced with observed sea surface temperature. The analysis of the results indicated that the model was capable of simulating the observed climatological circulation and the annual rainfall pattern over Tanzanian. The skill of simulation was highest during the October to December (OND) rainfall season where the model explained as high as 74% of the variance at some locations while during March to May (MAM) the variance explained over most locations was less than 40%. This result was consistent with the previous studies that have shown high (low) correlation between the OND (MAM) rainfall and the SST. Moreover, the El Nino Southern Oscillation (ENSO) signals are observed to be stronger during the OND season. The results from the study showed that the use MOS for down scaling improves the simulation skill. |
| 6 | 2008 | Simulation Of The Impact Of Deforestation On Rainfall In The Lake Victoria Basin
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Over the past four decades, Lake Victoria basin has experienced drastic environmental changes on account of both natural and anthropogenic factors. The natural factors include prolonged droughts and the recent emergence of water hyacinth in the Lake, while anthropogenic factors include the deforestation rates, poor agricultural practices, and destruction of critical wetlands. This study examines the potential impact of deforestation on the rainfall over the lake Victoria basin. To assess the potential impact of deforestation on rainfall over the region, the General Circulation Model (GCM) ECHAM5 was applied. ECHAM5 was used to predict the possible impact of land cover and land use changes on rainfall using land cover and land use scenarios based on the Integrated Model to Assess Global Environment (IMAGE). The projected vegetation cover for 2050 was used to model the impact of deforestation, which indicated a general decrease in the canopy. The results from the model indicate a decrease in rainfall over many parts, although some areas showed increased rainfall. From the study we conclude that while deforestation has an impact on climate, there seem to be a complex interaction between forest and the rainfall generation mechanism.
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| 7 | 2007 | Relarionship Between ENSO Parameters And The Trends And Periodic Fluctuations In East African Rainfall
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| 8 | 2007 | The Impact Of Climate Change On The Prevalent Of Malaria In Kenya
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| 9 | 2007 | East Africa Coastal Wet Spells During The Short Rains And The Anomalous Extreme Wet Spell Event Of October 1997.
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| 10 | 2007 | Performance Of Three-Way Cross Hybrids For Agronomic Traits And Resistance To Maize Streak Virus Disease In Kenya
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Maize Streak virus (MSV) disease is a major disease in many parts of Africa, and is the most important viral pathogen of maize in Kenya. A study was conducted in 2004 to evaluate the agronomic performance and maize streak virus (MSV) resistance of maize ( Zea mays check for this species in other resources L.) three-way crosses developed in Kenya. Twenty hybrids and one check were grown under normal conditions in a randomized complete block design, in two replications at Embu, 1540 masl; and Muguga, 2093 masl). In a parallel trial in Muguga, hybrids were also evaluated in two replications under artificial inoculation with MSV. The analyses of variance combined across environments showed significant differences (P<0.05) among genotypes for grain yield, days to 50% pollen shed, days to mid-silk and ear height. Genotype x environment interaction was significant (P<0.01) for grain yield and days to mid-silk, indicating some hybrids were more adapted in some environments. Grain yield for MU03-025 (10.04 t ha-1) was significantly better (P<0.05) than the check, H513 (7.53t ha-1). In the disease inoculated experiment, the best hybrids for disease resistance were MU03-012 and MU03-006 (score of 1.75), while H513 had a mean score of >3.0. The highest yielding hybrid under disease inoculation, MU03-026 showed yield gain of 5.2 t ha-1 above that of H513. The results indicate adoption of disease resistant hybrids would result in a higher maize yields in the mid-altitude areas of Kenya.
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| 11 | 2005 | Predictability Potential Of The Seasonal Rainfall Over Kenya Using Quasi-Biennial Oscillation Index
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Quasi-biennial oscillation (QBO) is an important natural fluctuation observed in the stratosphere temperatures, winds and trace gases (including ozone). Since a quasi-biennial oscillation is also detected in weather parameters such as sea surface temperature (SST), it has potential for the prediction of seasonal rainfall over Kenya. Prediction of rainfall is very important in ensuring food security. This study investigated the predictability of the seasonal rainfall over Kenya using QBO. Various methods were employed in the study. This included lag correlation composite analysis and analogue methods. Some locations indicated significant correlation values were observed between rainfall and QBO at lag between six to twelve months. It was however noted that the phase of QBO rather than the actual values may be used to predict seasonal rainfall over Kenya. The link between the tropospheric circulation and the QBO phase was also Investigated. The results was used to explain the mechanism linking the rainfall to QBO. |
| 12 | 2005 | The Environmental And Climatic Factors That Influence The Quality And Quantity Of The Well Water In Matunda Location, Uasingishu District In Kenya
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Water is the key to economic development and poverty reduction. Water is firmly linked with health and has important social implications. For example in areas where water is scare, women spent most of their time looking for water and hence being left with little time to attend to other social-economic activities and therefore they are unable to improve their living standards. While the Matunda location in Uasin Ngishu District is supplied with piped water from the Ziwa dam, the supply is seasonal and even when available it is unsuitable for domestic use. The residents of this area have therefore resorted to using well water for drinking and domestic use. Most of these wells are shallow, ranging from 15 to 40 feet deep. The present study aims at establishing whether this well water is safe for domestic use and whether the ground water is sustainable. The objective of the present study was to investigate the environmental and climatic factors that influence the quality and quantity of the well water. The environmental factors affecting the quality of water in this location were investigating by studying the social economic activities that take place within the locality which the climatic factors were studied by analyzing the variability of rainfall within the locality. The study indicated a high possibility of contamination of the wells and that the wells may also dry up during the prolonged droughts as indicated from the rainfall time series. |
| 13 | 2005 | Verification Of Seasonal Rainfall Forecast In Kenya During The Period 1998-203.
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| 14 | 2003 | The Predicable Patterns And Modes Of East Africa Seasonal Rainfall Following Global SST And ENSO Phase Forcing.
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Water is the key to economic development and poverty reduction. Water is firmly linked with health and has important social implications. For example in areas where water is scare, women spent most of their time looking for water and hence being left with little time to attend to other social-economic activities and therefore they are unable to improve their living standards. While the Matunda location in Uasin Ngishu District is supplied with piped water from the Ziwa dam, the supply is seasonal and even when available it is unsuitable for domestic use. The residents of this area have therefore resorted to using well water for drinking and domestic use. Most of these wells are shallow, ranging from 15 to 40 feet deep. The present study aims at establishing whether this well water is safe for domestic use and whether the ground water is sustainable. The objective of the present study was to investigate the environmental and climatic factors that influence the quality and quantity of the well water. The environmental factors affecting the quality of water in this location were investigating by studying the social economic activities that take place within the locality which the climatic factors were studied by analyzing the variability of rainfall within the locality. The study indicated a high possibility of contamination of the wells and that the wells may also dry up during the prolonged droughts as indicated from the rainfall time series. |
| 15 | 2003 | THE INFLUENCE OF WEATHER ON MENINGITIS
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Weather parameters influence human physiological adaptive activities, such as sweating, the general comfort and vulnerability to disease as well as the survival of disease-causing vectors and pathogens. In this study the influence of weather on Meningitis, one of the killer disease was investigated. Meningitis is caused by an inflammation of the meninges ( membrane) of the brain. The two main forms of meningitis are Aseptic (viral) and Meningococcal bacterial) meningitis. Both forms of meningitis are spread by direct contact, droplets, nasal discharge, and through the air. In the higher latitudes, the Aseptic form has been found to increase in late-summer and early autumn, while the Meningococcal meningitis has been found to increase in winter and spring. The objective of this study was to examine the effect of weather on the increase and spread of meningitis. Economic and social factors such as age and gender were also considered The data of the meningitis cases on monthly basis was collected from Kenyatta National Hospital and Aga Khan Hospital in Nairobi. All the meningitis cases were confirmed both clinically and by lumber puncture. The age, sex and total number of deaths were also obtained. The results from the analysis showed that meningitis cases were high in March-May, July, September, October and January. The reported male meningitis cases were higher than female cases. Adults and infants cases were more compared to children and teenagers. Minimum temperature indicated a stronger relationship with meningitis compared to other parameters. However, other weather parameters such as maximum temperature, rainfall, relative humidity were also significantly correlated with meningitis. |
| 16 | 2003 | Seasonal And Interannual Variability Of Carbon Dioxide And Its Relationship With SST.
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| 17 | 2003 | Utility Of Weather Information Dissemination By Media Industry
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| 18 | 2002 | The Relationship Between The Global Sea Surface Temperature Anomaly Patterns And The Interannual Variability Of Short Rains Over East Africa. In J. African Met Soc.
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| 19 | 1999 | The Influence Of The Global Sea Surface Temperature On The Interannual Variation Of March To May Rainfall Over East Africa.
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| 20 | 1999 | The Relationship Between Interannual Rainfall Variability Over Western Kenya And The Southern Oscillation
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 21 | 1999 | Composite Analysis
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 22 | 1999 | Practical Application Of Correlation
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 23 | 1999 | Fundamental Concepts In Seasonal Prediction And Current State Of Seasonal Prediction, Science And Technology
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 24 | 1998 | Divine Control Over Weather
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 25 | 1998 | The Influence Of The Sea Surface Anomalies On The March - May Rainfall Over East Africa.
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| 26 | 1998 | The Teleconnection Between El-Nino / Southern Oscillation And Extreme Rainfall Over East Africa.
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| 27 | 1998 | Simulation Of The Impacts Of Sea Surface Temperature (SST) Anomalies On The Short Rains Over East Africa
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| 28 | 1997 | The Frequency And Persistence Of Droughts In Eastern And Southern Africa.
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Western Kenya, which comprise the highlands west of the Rift Valley and the Lake Victoria basin, receive substantial amount of rainfall almost throughout the year. This region has therefore a high agricultural potential. The characteristics of rainfall in this part of the country are influenced by several factors, which range from meso-scale to global. One of the global teleconnection systems that influence the rainfall over this region is the Southern Oscillation (SO). The SO is an irregular, interannual and global scale see saw fluctuation in surface pressure between Indonesia and Southwest Pacific, and occurs at interval of 2 to 7 years. Both the rainfall and Southern Oscillation Index (SOI) data were obtained from the Drought Monitoring Centre (DMC) in Kenya. The Data consisted of monthly rainfall from 24 stations distributed over the region and the monthly-normalized SOI. The period of study was between 1957 to 1993. The seasonal data was derived from the data. The monthly and seasonal rainfall and SOI were subjected to correlation analysis. The t-test was used to determine the statistical significance of the computed correlation values. The spatial and temporal patterns of the correlation values were used to determine the nature of the relationship between the SO and rainfall over western Kenya during various months and seasons. Significant positive correlation values were observed during the months of July- September, while significant negative correlation values were observed during October-December. Low correlation values were however observed during January- May. The significant correlation values observed during July-September and October-December suggest that the SOI can be used as a predictor for the rainfall during these seasons |
| 29 | 1997 | Simulation Of The Impact Of El-Nino Southern Oscillation On The Short Rains Over East Africa
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| 30 | 1997 | Arificial Weather Modification
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| 31 | 1994 | The Impact Of The Global Sea Surface Temperature Patterns On Seasonal Rainfall In East Africa.
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| 32 | 1994 | Numerical Simulation Of The Influence Of SST Anomalies On The East Africa Seasonal Rainfall.
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| 33 | 1994 | Simulation Of The Diurnal Variations In The Atmospheric Variables Over Eastern Africa By The GCM
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Meteorological elements are observed to display diurnal and/ or semi diurnal variability. Therefore the ability of the UK 11-level GCM to correctly simulate these diurnal variations of weather elements may be used as a measure of how realistic the model is compared to the real atmosphere. The model is forced by the diurnal variation of insolation. In order to study the diurnal cycle of the GCM, the simulated April 1986 sub-daily fields were kept, sampled at every 6 hours. All the data were instantaneous values, apart from rainfall, snowfall, evaporation and sensible heat fluxes which were each accumulated over each time step (10 minutes) for the 6 hours period. The variables were then averaged over the model month (30 days). The mean daily fields were computed separately for 0600 GMT, 1200 GMT, 1800GMT and 0000 GMT. The diurnal variation of three variables, namely; surface temperature, rainfall and wind were examined. The simulated surface temperature indicated similar diurnal characteristic as the observed. Thus there was an increase in temperature from morning to afternoon, followed by a general decrease at night. The simulated diurnal variation of the precipitation, particularly the afternoon maximum, was consistent with the general observed diurnal variation of precipitation over many areas in East Africa. The simulated wind anomaly vector was observed to rotate clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. Such a diurnal behaviour of the wind has been observed in the real atmosphere. This characteristic is associated with the zonal movement of the region of maximum insolation (low pressure) from east to west. |
| 34 | 1993 | The Impact Of The Sea Surface Temperature Anomalies On The Long Rains In East Africa.
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Meteorological elements are observed to display diurnal and/ or semi diurnal variability. Therefore the ability of the UK 11-level GCM to correctly simulate these diurnal variations of weather elements may be used as a measure of how realistic the model is compared to the real atmosphere. The model is forced by the diurnal variation of insolation. In order to study the diurnal cycle of the GCM, the simulated April 1986 sub-daily fields were kept, sampled at every 6 hours. All the data were instantaneous values, apart from rainfall, snowfall, evaporation and sensible heat fluxes which were each accumulated over each time step (10 minutes) for the 6 hours period. The variables were then averaged over the model month (30 days). The mean daily fields were computed separately for 0600 GMT, 1200 GMT, 1800GMT and 0000 GMT. The diurnal variation of three variables, namely; surface temperature, rainfall and wind were examined. The simulated surface temperature indicated similar diurnal characteristic as the observed. Thus there was an increase in temperature from morning to afternoon, followed by a general decrease at night. The simulated diurnal variation of the precipitation, particularly the afternoon maximum, was consistent with the general observed diurnal variation of precipitation over many areas in East Africa. The simulated wind anomaly vector was observed to rotate clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. Such a diurnal behaviour of the wind has been observed in the real atmosphere. This characteristic is associated with the zonal movement of the region of maximum insolation (low pressure) from east to west. |
| 35 | 1993 | Relationship Between Rainfall Anomalies In Eastern And Southern Africa And El-Nino Southern Oscillation. Ibid
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| 36 | 1989 | Relationship Between Rainfall Anomalies In Eastern And Southern Africa And El-Nino Southern Oscillation. Ibid.
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Meteorological elements are observed to display diurnal and/ or semi diurnal variability. Therefore the ability of the UK 11-level GCM to correctly simulate these diurnal variations of weather elements may be used as a measure of how realistic the model is compared to the real atmosphere. The model is forced by the diurnal variation of insolation. In order to study the diurnal cycle of the GCM, the simulated April 1986 sub-daily fields were kept, sampled at every 6 hours. All the data were instantaneous values, apart from rainfall, snowfall, evaporation and sensible heat fluxes which were each accumulated over each time step (10 minutes) for the 6 hours period. The variables were then averaged over the model month (30 days). The mean daily fields were computed separately for 0600 GMT, 1200 GMT, 1800GMT and 0000 GMT. The diurnal variation of three variables, namely; surface temperature, rainfall and wind were examined. The simulated surface temperature indicated similar diurnal characteristic as the observed. Thus there was an increase in temperature from morning to afternoon, followed by a general decrease at night. The simulated diurnal variation of the precipitation, particularly the afternoon maximum, was consistent with the general observed diurnal variation of precipitation over many areas in East Africa. The simulated wind anomaly vector was observed to rotate clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. Such a diurnal behaviour of the wind has been observed in the real atmosphere. This characteristic is associated with the zonal movement of the region of maximum insolation (low pressure) from east to west. |
| 37 | 1987 | Spatial And Temporal Characteristics Of Droughts In Eastern And Southern Africa.
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Meteorological elements are observed to display diurnal and/ or semi diurnal variability. Therefore the ability of the UK 11-level GCM to correctly simulate these diurnal variations of weather elements may be used as a measure of how realistic the model is compared to the real atmosphere. The model is forced by the diurnal variation of insolation. In order to study the diurnal cycle of the GCM, the simulated April 1986 sub-daily fields were kept, sampled at every 6 hours. All the data were instantaneous values, apart from rainfall, snowfall, evaporation and sensible heat fluxes which were each accumulated over each time step (10 minutes) for the 6 hours period. The variables were then averaged over the model month (30 days). The mean daily fields were computed separately for 0600 GMT, 1200 GMT, 1800GMT and 0000 GMT. The diurnal variation of three variables, namely; surface temperature, rainfall and wind were examined. The simulated surface temperature indicated similar diurnal characteristic as the observed. Thus there was an increase in temperature from morning to afternoon, followed by a general decrease at night. The simulated diurnal variation of the precipitation, particularly the afternoon maximum, was consistent with the general observed diurnal variation of precipitation over many areas in East Africa. The simulated wind anomaly vector was observed to rotate clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. Such a diurnal behaviour of the wind has been observed in the real atmosphere. This characteristic is associated with the zonal movement of the region of maximum insolation (low pressure) from east to west. |
| 38 | 1987 | The Characteristics Of Rainfall In Ethiopia And Its Relationship To El-Nino Southern Oscillation
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Ethiopia is one of the countries on the eastern side of Africa which has high spatial and temporal variability of rainfall. The trade winds are the major source of moisture in this region. The chatacteristics of the trade winds are controlled by the location, intensity and orientation of the majorbquasi-permanent anticyclones of Africa together with other general circulation parameters such as sea surface temperatures, jet streams, easterly waves and extratropical weather systems. The study showed that years of strong El-Nino are characterized by severe droughts over Ethiopia. |
| 39 | 1987 | Rainfall Characteristics In Ethiopia.
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Ethiopia is one of the countries on the eastern side of Africa which has high spatial and temporal variability of rainfall. The trade winds are the major source of moisture in this region. The chatacteristics of the trade winds are controlled by the location, intensity and orientation of the majorbquasi-permanent anticyclones of Africa together with other general circulation parameters such as sea surface temperatures, jet streams, easterly waves and extratropical weather systems. The study showed that years of strong El-Nino are characterized by severe droughts over Ethiopia. |
