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Assessing Agricultural Risk in Africa Using Satellite Data and Land Surface Models
Droughts pose a major risk in most African countries including Ghana where agricultural activities are heavily dependent on rainfall. Efforts at assessing droughts and providing decision support tools to farmers are hampered by a lack of rainfall and other meteorological data over many parts of Africa. Satellite based rainfall measurements have been suggested to fill the rainfall data gaps over Africa to enable effective assessment of droughts. Traditional methods of assessing droughts have been based on statistical formulations that relied mostly on precipitation. This approach to assessing d ...Published by: University of Reading ; 2015
Droughts pose a major risk in most African countries including Ghana where agricultural activities are heavily dependent on rainfall. Efforts at assessing droughts and providing decision support tools to farmers are hampered by a lack of rainfall and other meteorological data over many parts of Africa. Satellite based rainfall measurements have been suggested to fill the rainfall data gaps over Africa to enable effective assessment of droughts. Traditional methods of assessing droughts have been based on statistical formulations that relied mostly on precipitation. This approach to assessing droughts ignores important soil water balance processes such as evapotranspiration and antecedent soil moisture which limits its applicability to agricultural drought assessment. We use in-situ observation data (OBS), satellite estimated rainfall data (TAMSAT) and the Joint UK Land and Environment Simulator model to study soil moisture and how it impacts on crop production. The response of soil moisture to changes in vegetation and soil type is tested through a series of experiments in which the soil and vegetation parameters in JULES are changed. TAMSAT was found to persistently underestimate the intensity and amount of rainfall and as a result soil moisture content over northern Ghana but showed good skill replicating the inter-annual variations and the occurrence of rainfall during the rainy season. Soils with greater clay contents showed more tendencies to have drought than those with lesser clay content. Land surfaces with C3 grass were found to be less prone to droughts than those with C4 grass. Meteorological wet and dry years were found not to correspond to agricultural wet and dry years highlighting the importance of using soil moisture for assessment agricultural drought as was done in this study.
Notes: A dissertation submitted in partial fulfilment of the requirement for the degree of Master of Science in Applied Meteorology and Climate with Management. - If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).
Language(s): English
Format: DigitalTags: Drought forecasting ; Satellite ; Agrometeorology ; Region I - Africa ; Thesis - WMO Fellowship Division
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Assessing the impacts of temporal resolution of precipitation forcing data on the surface energy and water balance
In urban climate research, spatial and temporal variability of precipitation is always a critical element for numerical modelling. However, the effects of temporal resolution of precipitation forcing data has received little attention. Moreover, there has always been a difference practically and theoretically in the availability of precipitation data. This study was carried out to assess the impact of temporal resolution of precipitation forcing data on the modelled surface energy and water balance using available data from a site at the Strand campus of Kings College London. Analysis has been ...Assessing the impacts of temporal resolution of precipitation forcing data on the surface energy and water balance
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Published by: University of Reading ; 2015
In urban climate research, spatial and temporal variability of precipitation is always a critical element for numerical modelling. However, the effects of temporal resolution of precipitation forcing data has received little attention. Moreover, there has always been a difference practically and theoretically in the availability of precipitation data. This study was carried out to assess the impact of temporal resolution of precipitation forcing data on the modelled surface energy and water balance using available data from a site at the Strand campus of Kings College London. Analysis has been carried out using 5 minute rainfall data as a reference, compared with rainfall data accumulated to various temporal resolutions. The results suggest that as the temporal resolution of precipitation forcing data decreased, there are significant impacts on the modelled output depending on the timing of rainfall occurrence, rainfall intensity and the rainfall duration. The modelled evaporation and runoff, as well as other variables such as the turbulent heat fluxes, tends to deviate from referenced rainfall data. For days with daily total rainfall amount more than median but less than maximum, results shows more significant impacts on the modelled surface energy balance and water balance. Under conditions of no rain, as expected, the impacts of temporal resolution were less significant. This study highlights the importance of high resolution precipitation forcing data in urban areas for modelling for a wide range of applications.
Notes: A dissertation submitted in partial fulfilment of the requirement for the degree of Master in Applied Meteorology and Climate with Management AMCM) - If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).
Language(s): English
Format: DigitalTags: Precipitation ; Climate model ; Research ; Thesis - WMO Fellowship Division
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Instability Indices and Heavy Rainfall Forecast in a Maritime Environment
Forecasting heavy rainfall associated with in-situ convective cloud development over small island states is a challenge in operational forecasting as not all numerical models are able to resolve convection at such small scales. Forecasting of such phenomena is mainly based on prevailing local conditions and the use of a plethora of thermodynamic indices derived from the local sounding. This study is an effort to assess the suitability of the different available indices, hereafter referred as traditional indices, to forecast heavy rainfall from local convection, commonly known as pure sea breez ...Published by: University of Reading ; 2015
Forecasting heavy rainfall associated with in-situ convective cloud development over small island states is a challenge in operational forecasting as not all numerical models are able to resolve convection at such small scales. Forecasting of such phenomena is mainly based on prevailing local conditions and the use of a plethora of thermodynamic indices derived from the local sounding. This study is an effort to assess the suitability of the different available indices, hereafter referred as traditional indices, to forecast heavy rainfall from local convection, commonly known as pure sea breeze, over Mauritius. An attempt is also made to improve the forecast through modifications of the traditional indices, to include lower boundary layer temperature and moisture parameters. Suitable thresholds of all these indices are also determined via scatter plots of the events which are categorised into weak, moderate and severe based on hourly rainfall intensity.
Notes: Dissertation Submitted in Partial Fulfilment For a Master in Applied Meteorology with Climate and Management.
Supervisor: Dr. Pete Inness - If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).Language(s): English
Format: DigitalTags: Precipitation forecasting ; Marine environment ; Thesis - WMO Fellowship Division
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Investigating apparent aerosol effects on precipitation in climate model simulations
Aerosols in the atmosphere serve as condensation nuclei for the cloud formation. This brings an important influence on the microphysical properties of cloud water that in turn affect the processes in the formation of precipitation. Aerosol-cloud-precipitation interaction which simultaneously change cloud albedo interest many studies to find out aerosol impact on precipitation formation. The studies were done by observation measurement and simulation. UK Met Office Unified Model (UM) is one model that includes aerosol direct and indirect effect in the NWP configuration which leads to study aero ...Published by: University of Reading ; 2015
Aerosols in the atmosphere serve as condensation nuclei for the cloud formation. This brings an important influence on the microphysical properties of cloud water that in turn affect the processes in the formation of precipitation. Aerosol-cloud-precipitation interaction which simultaneously change cloud albedo interest many studies to find out aerosol impact on precipitation formation. The studies were done by observation measurement and simulation. UK Met Office Unified Model (UM) is one model that includes aerosol direct and indirect effect in the NWP configuration which leads to study aerosol impact on precipitation. Recent study use UM to simulate precipitation susceptibility when using aerosol-cloud interaction and no aerosol-cloud interaction which both showing precipitation dependency on aerosol. This dissertation investigate what particular factor and process leads to the apparent precipitation susceptibility by using UM SCM (Single Column Model) to simulate marine boundary-layer clouds and investigate several factor that may cause the apparent precipitation susceptibility including wind and time steps. Simulation with applying different horizontal and vertical wind tendency and time steps was done. Precipitation susceptibility found to be sensitive with the time step choices and wind tendency.
Notes: A dissertation submitted to the University of Reading in partial fulfilment of the Master of Science
Degree in Applied Meteorology, Climate with Management (AMCM) - If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).Language(s): English
Format: Digital (ill., charts, maps)Tags: Climate model ; Precipitation ; Aerosols ; Thesis - WMO Fellowship Division
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Rainfall characteristics over Togo and their related atomospheric circulation anomalies: In Journal of Environmental & Agricultural Sciences, 5:34-48
This study attempts to reveal features of rainfall over Togo, in relationship to the
prevailing atmospheric circulation. The study employed correlation analysis and composite analysis in
the analysis of rainfall, sea surface temperature, wind, and humidity. Empirical orthogonal functions
(EOF) analysis was employed in this study. The years: 1989, 1991, 1995, 2003 and 2007 were
identified to be anomalously wet years while 1982, 1983, 1990, 1992, 2001 and 2006 fall in the
anomalously dry years’ category. The dominant mode of variability exhibits a dipole patter ...Rainfall characteristics over Togo and their related atomospheric circulation anomalies: In Journal of Environmental & Agricultural Sciences, 5:34-48
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Kpaikpai Batebana ; Bob Alex Ogwang ; Zin Mie Mie Sein ; Faustin Katchele Ogou ; Victor Ongoma ; Jean Paul Ngarukiyimana
Published by: Batebana et al. ; 2015This study attempts to reveal features of rainfall over Togo, in relationship to the
prevailing atmospheric circulation. The study employed correlation analysis and composite analysis in
the analysis of rainfall, sea surface temperature, wind, and humidity. Empirical orthogonal functions
(EOF) analysis was employed in this study. The years: 1989, 1991, 1995, 2003 and 2007 were
identified to be anomalously wet years while 1982, 1983, 1990, 1992, 2001 and 2006 fall in the
anomalously dry years’ category. The dominant mode of variability exhibits a dipole pattern, and
explains 36% of the total variance. The rainfall was robustly correlated to Southern Atlantic Ocean
Dipole (SAOD). The predominant wind flow over the country is westerly. Wet years were associated
with anomalous low pressure area over Togo as opposed to the dry years which exhibited an anomalous
high pressure area in the same region at low level. The results from this study provided basic climate
information on Togo’s rainfall. The SAOD can be further investigated of how it can be factored into
seasonal rainfall forecasting over Togo. Accurate and timely rainfall forecasting will help to minimize
the devastating impacts associated with anomalous rainfall in the region.Notes: If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).
Language(s): English
Format: DigitalTags: Atmospheric circulation ; Precipitation ; Togo ; Thesis - WMO Fellowship Division
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The impacts of fog and thunderstorms on aircraft operations : a case study of Wilson Airport Nairobi Kenya
Abongnwi Ngwa Lumfuh - 2014Adverse weather is the main cause of the alterations to operations at Wilson airport. At Wilson airport, occurrence of fog and low ceiling, cross winds, thunderstorm and heavy rainfall are considered the main causes of adverse weather hampering the aircraft operations. The purpose of this study is to investigate the impacts of fog and thunderstorm on aircraft operations at Wilson airport. The impact is measured in terms of delay, diversion, cancelation and economic value of these actions. The data on fog and thunderstorm data was obtained from Kenya Meteorological Service (Climatological secti ...Permalink![]()
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Report of the three months Attachment at the European Centre for Medium-Range
The attachment took place at the ECMWF headquarters in Reading, United Kingdom from 29th April-30th July 2013. The program was sponsored by the World Meteorological Organisation (WMO).Permalink![]()
Assessment of prone areas to heavy rainfall in Tanzania and its associate circulation anomalies during march-may rainfall season
Mafuru Kantamla Biseke - College of Atmospheric Science, Nanjing University of Information Science and Technology, 2013Tanzania is one among the most other sub-Sahara African countries where Agriculture production is strongly depending on rainfall, a key factor which determine the livelihood of 70% of the total population. An adequate amount of rainfall per season reasonably help the farmer to accomplish his/her goal in a positive way, while an excessive amount of rainfall impacts on both people’s livelihood and agricultural production leading into reduction in manpower and nation’s GDP. In recent years, Tanzania suffered a successive scenario of heavy rainfall over different areas of the country, the majority ...Permalink![]()
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Rainfall and temperature characteristic over Zambia
Temperature and rainfall are important elements of climate Zambia where several sectors of the economy depend mostly on water resources. Zambia normally receives the bulk of its annual rainfall from November to March (NDJFM) as the ITCZ moves south and experience high temperatures. The major objective of the study was to investigate the rainfall and temperature characteristic over Zambia.Permalink![]()
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Analysis of heavy rainfall events over Dar es Salaam city: A necessity to lessen flood risks
Floods are a threat to many cities especially in the developing countries and cities found near the coastal areas where the population pressure, unplanned settlements and poor infrastructures are most evident. Climate change also poses a higher flood risks in these areas due to increased frequency and intensity of extreme rainfall events. In this study analysis of extreme rainfall over Dar es Salaam city in Tanzania was done. The analysis employed empirical as well as hydrological frequency modeling to annual maximum daily rainfall events for 5 of the meteorological stations found within the c ...Permalink![]()
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Climate Response over Selected Urban and Desert Areas in Northern China
Many studies carried out have shown evidence of regional temperature and precipitation variability along with global climate changes. A key issue is whether these variability follow trends that are uniform or others have increasing trends while others decreasing trend. And this study was carried out using Mann-Kendall trend test method and regression analysis method with the data observed by a total of 20stations to investigate the trends of temperature and precipitation in northern China. 10stations were selected from urban areas (section 1.4.2: table 1.1) and another 10stations were selected ...Permalink![]()
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Climate Prediction and Monitoring for Egypt
Apart from the northern coast, most of Egypt is desert. However, the northern coastal region experiences some precipitation mainly during winter. We investigate the variability of wintertime (December, January and February) precipitation in North Egypt during the 30-yr interval 1976-2005 and its relationship with the North Atlantic Oscillation during winter and subtropical jet stream.Permalink![]()
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Climate Prediction and Monitoring for Uganda
Uganda is located between latitudes 1.5 0 S to 4.5 0 N and longitudes 28o E to 35 0 E. It contains complex topography that includes large Lakes, Rivers, Great Rift Valley and Mountains, and supports varied wildlife of scientific and economic value. Due to its Equatorial location, this country is expected to receive abundant rainfall throughout the year. This is, however, not the case as frequent occurrences of years of insufficient rainfall for agricultural activities have been observed. Rainfall over Uganda exhibits large spatial and temporal variability. The inter-annual variability has feat ...Permalink![]()
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Climate Prediction and Monitoring for Burundi
“The dominant pattern of Burundi rainfall is the seasonal move of the dominant Intertropical convergence zone (ITCZ), the Congo air mass and the interconnection with EL Nino/Southern oscillation (ENSO) phenomena. Much of Burundi experiences a bimodal seasonal distribution of rainfall with maxima occurring in the March- April and November. The Interannual variability of rainfall in Burundi shows interesting association with atmospheric and oceanic phenomena. We investigate the variability of rainfall using OND (October, November, December) and MAM (March, April, May) precipitation in Burundi du ...Permalink![]()
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Storm surges and coastal erosion in Bangladesh - State of the system, climate change impacts and 'low regret' adaptation measures
The effects of global environmental change, including coastal flooding stemming from storm surges as well as reduced rainfall in drylands and water scarcity, have detrimental effects on countries and megacities in the costal regions worldwide. Among these, Bangladesh with its capital Dhaka is today widely recognised to be one of the regions most vulnerable to climate change and its triggered associated impacts. Natural hazards that come from increased rainfall, rising sea levels, and tropical cyclones are expected to increase as climate changes, each seriously affecting agriculture, water & fo ...Permalink