Browsing by Author "Ndetto, Emmanuel Lubango"

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Effects of UrbanConfiguration on human thermal conditions in a typical tropical African Coastal City
(Hindawi Publishing Corporation, 2013) Ndetto, Emmanuel Lubango; Matzarakis, Andreas
A long-term simulation of urban climate was done using the easily available long-term meteorological data from a nearby synoptic station in a tropical coastal city of Dar es Salaam, Tanzania. he study aimed at determining the efects of buildings’ height and street orientations on human thermal conditions at pedestrian level. he urban coniguration was represented by a typical urban street and a small urban park near the seaside. he simulations were conducted in the microscale applied climate model of RayMan, and results were interpreted in terms of the thermal comfort parameters of mean radiant (� mrt ) and physiologically equivalent (PET) temperatures. PET values, high as 34 ∘ C, are observed to prevail during the aternoons especially in the east-west oriented streets, and buildings’ height of 5 m has less efect on the thermal comfort. he optimal reduction of � mrt and PET values for pedestrians was observed on the nearly north-south reoriented streets and with increased buildings’ height especially close to 100 m. Likewise, buildings close to the park enhance comfort conditions in the park through additional shadow. he study provides design implications and management of open spaces like urban parks in cities for the sake of improving thermal comfort conditions for pedestrians.
Investigating the use of satellite derived rainfall for agricultural insurance in Tanzania
(University of Reading, 2009) Ndetto, Emmanuel Lubango
In most African countries, agriculture is mainly rain-fed hence vulnerable to risks associated with weather and climatic hazards. Excess and inadequate rainfall both contribute greatly agriculture losses in these developing countries leaving the rural population poor and lack of food security. Index insurance particularly that uses rainfall as a proxy for loss is envisaged to relieve the rural farmers from the risks. Index insurance thus needs real-time availability of weather data. Satellite based rainfall is therefore sought to be used in order to extend this innovation to other places where weather stations are not closely available. This study investigated the use of satellite derived rainfall in agriculture insurance in two zones of Tanzania (north eastern highlands and south western highlands). The study used satellite products from TAMSAT archive and TRMM products. Rain gauge data and crop yield data for maize for Tanzania, altogether covering a period from 1997 to 2007 were also used. Calibration results for TAMSAT method suggests that -30°C is the optimal threshold temperature for most months except for January, February and October in some areas. Further, correlation results between rain gauge and satellite rainfall shows good results for both north eastern and south-western highlands where the comparison were done. However, poor correlation results are indicated in April and October for north eastern highlands. Co-fluctuation of yield and rainfall data was investigated and it was revealed that there is a good relationship in north-eastern highlands as compared to south western highlands. These results indicate a high potential of using satellite based rainfall in agriculture insurance. A general conclusion for using satellite rainfall in agriculture insurance will better be reached after doing similar and further analysis on the whole area. The current results can therefore be treated as preliminary to this novel idea of satellite-rainfall application in agriculture weather index insurance.