Spatial and temporal characteristics of monthly rainfall over Limbang River Basin, Northern Borneo: an evaluation through multivariate statistics

Abstract

Identification of homogeneous rainfall regime in Limbang River Basin (LRB), Malaysia, Northern Borneo and its temporal characteristics were elucidated in the present study. Multivariate statistical techniques were used to characterize 15 years (2000–2015) monthly rainfall data from twelve rain gauging stations present in LRB. Analysis of monthly accumulated rainfall indicates that LRB receives maximum rainfalls during January, April, November, December and least in July. Three dominant clusters (C1, C2 and C3) of homogeneous rainfall were identified by Ward’s method of hierarchical clustering, and multivariate statistics were applied to understand its temporal characteristics. Comparing the clusters formed in different elevations in LRB, cluster-3 which covers middle catchment region shows the highest accumulated monthly (487 mm in November) and annual rainfall (4571 mm). At the same time, all the clusters shown more or less similar pattern of temporal rainfall distribution with varying dispersion and skewness and these altogether contribute 74% of annual rainfall received by LRB. Though the study area is considered as unique climatic (equatorial tropical rainforest) regime, the observed variation in rainfall among the clusters can be attributed to the factors such as locations of rain gauging stations (elevation and geomorphology), characteristics of hills/mountains, proximity to ocean and wind characteristics in the region. The findings of present research will serve as an essential pre-requisite dataset for any hydrological development program in the river basin.