-Rizaludin Mahmud, Aina Afifah Yusof, Mazlan Hashim, Mohd. Nadzri Mohd Reba
Weekly Newsletter
It is a good news for the ungauged or under-measured micro-scale catchment in coastal humid tropic. Mapping the daily rainfall is now possible at 200m resolution. For readers information, there are significantly many ungauged sub-basins in humid tropics that eventually very productive and responsible for many applications including water resources, agriculture and sustaining life in various ecosystems niche across the catchment.
Although using satellite data is a useful option, the size of the sub-basins is literally small (<10km²) to be represented by the relatively coarse resolution satellite data (~100km²). Therefore, an appropriate downscaling approach is required to refine the satellite data. The downscaling technique used the hourly basis of vertical velocity obtained from wind measurement and topography model to estimate the probability of rainfall at every 200m grid. Subsequently, the probability of rainfall which later known as downscaling co-efficient (DC) is used to re-compute the rainfall estimates from the Global Precipitation Mission (GPM) satellite data.
(Source: Mahmud et al., 2020)
The experiment conducted in the Paka-Dungun basin in Terengganu able to produce high resolution satellite data with greater quantitative and qualitative accuracy.
The downscaling technique is developed through modifying the Mass-Dempsey orography model; parameterization of the vertical velocity component with input from high resolution topography and temporal local wind measurement. This research has been successfully published in Water journal, edition 6, year 2020 under the special issue edition of Modeling Precipitation in Space and Time editor by Prof. Gabriele Buttafoco. The access to the full paper can be reached at https://doi.org/10.3390/w12061661.
References:
Mahmud M. R., Yusof A. A. M., Reba M. N. M., Hashim M. (2020). Mapping the Daily Rainfall over an Ungauged Tropical Micro-Watershed: A Downscaling Algorithm Using GPM Data. Water, 12 (6), 1661
Name: Mohd. Rizaludin Mahmud
Date: 26.06.2020
Email address: rizaludin@utm.my