降雨強度累積時間率分布のガンマ分布近似 : 衛星通信における降雨減衰の時間率特性(2)

概要

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A practical method is described for determining the gamma distribution parameters, k and λ, with the view of representing rainfall rate distributions. The technique is based upon a group of the cumulative gamma distribution of various k with both X (relative rainfall rate) and Y (probability) axis log-scaled and an observed rainfall rate distribution drawn to the same scale. With both X-axes kept one another, the observed distribution is shifted in the X-axis direction so that it fits to one of the gamma distributions to maximum extent. Then, k is that of the overlapping gamma distribution and λ is the ratio of the corresponding X co-ordinates. The cumulative gamma distribution is easily calculated thanks to L. Boithias' useful approximation formula. This method allows simultaneous estimation how this representation is accurate. Elaborate wrok can offer more precise value of the parameters if necessary.
岡山理科大学の論文