AREAL PRECIPITATION AND DEPTH-AREA DURATION CURVES FOR REGIONS IN TRINIDAD USING A TRIANGULATED GRID

S.S. BALKISSOON, S.R. GUNAKALA, H.M. AZAMATHULLA

Abstract


A triangulated grid was used to estimate the areal precipitation for regions in Trinidad. The rain gauge stations, from three hydrometric units, served as nodal points. Three parameters, nodal rainfall, its x and y co-ordinates, were used to determine the areal precipitation through linear interpolation. Thereafter, the total elemental volume of rainfall and the elemental average rainfall precipitation were determined. To estimate the areal precipitation of the grid for each month, a decadal (2006-2015) average of the monthly rainfall values was calculated. The largest rainfall month was November and the lowest areal precipitation occurred in March with approximately 78mm. The smaller irregular shaped elements in the mountainous regions had the most differences in areal precipitation than the other elements in the grid. Optimization of the grid was done by the reconfiguration and redistribution of the nodes. This adjusted grid resulted in more similarity in rainfall patterns for both seasons, dry and rainy. The Depth-Area Duration Curves (DAD), for each month and for each season, show the changes of the average precipitation depth with area span by the grid. Temporally, the areal precipitation were oscillating for both seasons as the years progressed from 2006-2015. It should be noted though that, as the years progressed, the amplitude of the oscillations decreased in the rainy season.


Keywords


Triangulated Grid, Areal Precipitation, Depth-Area Duration Curves (DAD)

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