The design of a regional minimum raingauge network

Basalirwa, Charles; Ogallo, L.J.; Mutua, Francis

doi:10.1080/07900629308722598

Cited by 13 publications

(3 citation statements)

References 3 publications

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“…There are a Kayombo and Jorgensen, 2006) number of other meteorological stations within the LVB, but all are found in the same (Lake Victoria) climatological zone with homogeneous anomalies. Past studies have shown significant homogeneity in the patterns of rainfall anomalies in East Africa including Lake Victoria basin, resulting into common use of single rain gauge location to represent large areas (Ogallo 1988(Ogallo , 1993Basalirwa et al 1993;Awange et al 2007b). Several authors have also noted that large scale moisture transported by monsoonal winds enhance basin precipitation significantly.…”

Section: Data Sourcementioning

confidence: 95%

Falling Lake Victoria water levels: Is climate a contributing factor?

et al. 2008

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Recently, and perhaps most threatening, Lake Victoria water level has been receding at an alarming rate. A recent study suggested the possibility of the expanded hydroelectric power station in Uganda. However, since the lake receives 80% of its refill through direct rainfall and only 20% from the basin discharge, climatic contributions cannot be ignored, since the 80% water is directly dependant on it. It is therefore necessary to investigate climatic contribution to the declining Lake Victoria water level observed over a long period, i.e., 30 years. This contribution uses 30 years period anomalies for rainfall, river discharge and lake level changes of stations within Lake Victoria basin to analyse linear and cyclic trends of climate indicators in relation to Lake levels. Linear trend analysis using the Student's t test indicate a decreasing pattern in rainfall anomalies, with the slope being statistically similar to those of water levels at both Kisumu, Maziba and Jinja stations Climatic Change (for the same period of time , thus showing a strong correlation. On the other hand, cyclic trend analysis using Discrete Fourier Transform (DFT) shows cyclic period of water level to coincide with those of droughts and rainfall. The strong relationship between climatic indicators of drought and rainfall on one-hand and lake levels on the other hand signifies the need to incorporate climate information in predicting, monitoring and managing lake level changes.

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Section: Data Sourcementioning

confidence: 95%

Falling Lake Victoria water levels: Is climate a contributing factor?

et al. 2008

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“…Thus, identification and selection of the best network configuration having optimal number and locations of rain gauge stations is the sole objective of the network design. Hence, the optimal rain gauge network should contain the number and locations of rain gauge stations in such a way that it can yield optimum rainfall information with minimum uncertainty and cost (Kassim and Kottegoda, ; Basalirwa et al, ; Pardo‐Igúzquiza, ). One can approach the problem either by eliminating redundant stations from the network to minimize the cost or by expanding the network with installation of additional stations to reduce the estimation uncertainty (Mishra and Coulibaly, ).…”

Section: Introductionmentioning

confidence: 99%

Optimal design of rain gauge network in the Middle Yarra River catchment, Australia

Adhikary

Yilmaz

Muttil

2014

Hydrological Processes

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Abstract:Rainfall data are a fundamental input for effective planning, designing and operating of water resources projects. A welldesigned rain gauge network is capable of providing accurate estimates of necessary areal average and/or point rainfall estimates at any desired ungauged location in a catchment. Increasing network density with additional rain gauge stations has been the main underlying criterion in the past to reduce error and uncertainty in rainfall estimates. However, installing and operation of additional stations in a network involves large cost and manpower. Hence, the objective of this study is to design an optimal rain gauge network in the Middle Yarra River catchment in Victoria, Australia. The optimal positioning of additional stations as well as optimally relocating of existing redundant stations using the kriging-based geostatistical approach was undertaken in this study. Reduction of kriging error was considered as an indicator for optimal spatial positioning of the stations. Daily rainfall records of 1997 (an El Niño year) and 2010 (a La Niña year) were used for the analysis. Ordinary kriging was applied for rainfall data interpolation to estimate the kriging error for the network. The results indicate that significant reduction in the kriging error can be achieved by the optimal spatial positioning of the additional as well as redundant stations. Thus, the obtained optimal rain gauge network is expected to be appropriate for providing high quality rainfall estimates over the catchment. The concept proposed in this study for optimal rain gauge network design through combined use of additional and redundant stations together is equally applicable to any other catchment.

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“…Patra [1] applied the coefficient of variance and allowable percentage of error to estimate the optimal number of rain gauge stations. Basalirwa et al [7] attempted to design a minimum rainfall network by using principal component analysis. Likewise, geostatistics is frequently used in the design of rainfall networks.…”

Section: Introductionmentioning

confidence: 99%

Rainfall Network Optimization Using Radar and Entropy

Yeh

Chen

Chang

et al. 2017

Entropy

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Abstract:In this study, a method combining radar and entropy was proposed to design a rainfall network. Owing to the shortage of rain gauges in mountain areas, weather radars are used to measure rainfall over catchments. The major advantage of radar is that it is possible to observe rainfall widely in a short time. However, the rainfall data obtained by radar do not necessarily correspond to that observed by ground-based rain gauges. The in-situ rainfall data from telemetering rain gauges were used to calibrate a radar system. Therefore, the rainfall intensity; as well as its distribution over the catchment can be obtained using radar. Once the rainfall data of past years at the desired locations over the catchment were generated, the entropy based on probability was applied to optimize the rainfall network. This method is applicable in remote and mountain areas. Its most important utility is to construct an optimal rainfall network in an ungauged catchment. The design of a rainfall network in the catchment of the Feitsui Reservoir was used to illustrate the various steps as well as the reliability of the method.

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The design of a regional minimum raingauge network

Cited by 13 publications

References 3 publications

Falling Lake Victoria water levels: Is climate a contributing factor?

Falling Lake Victoria water levels: Is climate a contributing factor?

Optimal design of rain gauge network in the Middle Yarra River catchment, Australia

Rainfall Network Optimization Using Radar and Entropy

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