Abstract
Precise spatio-temporal measurements of rainfall during seasonal monsoons are critical for accurate hydrologic analyses in the tropical regions of Southeast Asia. The use of satellite precipitation data is technologically sound but requires downscaling to minimize inherent uncertainties. The uncertainties at a local climate regime that are essential to be resolved are rarely reported; consequently, such work needs attention. To address this problem, we validated the Tropical Rainfall Measuring Mission (TRMM) precipitation data using high-resolution areal precipitation (0.125 deg.) at a seasonal scale. This study examined the performance of the monthly rainfall data product (TRMM 3B43) at the seasonal monsoon scale in the local climate region of Peninsular Malaysia. The high-resolution areal precipitation data (0.125 deg.) were derived from a dense rain gauge network ever collected in Peninsular Malaysia (n = 984). Three relevant performance elements were evaluated: (i) the ability to depict temporal rainfall variation (ii) the quantitative error between TRMM and ground rainfall; and (iii) the ability to estimate the actual rainfall amount. We found that the ability of monthly TRMM data to depict rainfall variation and its tendency to propagate large errors varied seasonally. The correlation between TRMM and ground rainfall was good during the wettest period in all local climate regions. The error was related to the northeast monsoon and inter-monsoon 2 (September–October). Meanwhile, the TRMM ratio varied regionally, rather than seasonally. Determining the local-scale uncertainties will facilitate future downscale activities using TRMM satellite data in this region.
Highlights
Precise seasonal monsoon rainfall measurement is critical for accurate hydrologic prediction, simulation, and assessment in humid tropical regions
Despite its promising potential for many regions worldwide [3,4,5,6,7], its sensitivity for local-scale rainfall in a small region, one located in Southeast Asia, is contentious due to inherent uncertainties. These uncertainties include the effect of upscaling the instantaneous rain rate to an effective temporal scale [8], the insensitivity of the Tropical Rainfall Measuring Mission (TRMM) precipitation algorithms to low- and high-precipitation clouds [9,10], and the coarse grid size of the TRMM data for resolving local rainfall patterns [11].Prompt actions must be taken to mitigate these uncertainties in order to obtain improved rainfall estimates from the TRMM data that suit local scale applications
The ability of TRMM to estimate actual rainfall varied among local climatic regions and conditions were often overestimated; the extent of overestimation was 30%–50% in the southwest, 60%–70% in the highland region, 50%–100% in the east, 70%–100% in the west and 120%–160% in the northwest
Summary
Precise seasonal monsoon rainfall measurement is critical for accurate hydrologic prediction, simulation, and assessment in humid tropical regions. Despite its promising potential for many regions worldwide [3,4,5,6,7], its sensitivity for local-scale rainfall in a small region, one located in Southeast Asia, is contentious due to inherent uncertainties These uncertainties include the effect of upscaling the instantaneous rain rate to an effective temporal scale [8], the insensitivity of the TRMM precipitation algorithms to low- and high-precipitation clouds [9,10], and the coarse grid size of the TRMM data for resolving local rainfall patterns [11].Prompt actions must be taken to mitigate these uncertainties in order to obtain improved rainfall estimates from the TRMM data that suit local scale applications. In the case of Peninsular Malaysia, improving the coarse resolution of the TRMM data and minimizing the quantitative seasonal error from the rainfall estimates are essential for obtaining precise seasonal rainfall information due to its small size and the high rainfall excess
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
