Investigating the response of hydrological processes to El Niño events using a 100-year dataset from the western Pacific Ocean

Sekhon, Natasha; David, Clarissa C.; Geronia, Mart Cyrel M.; Custado, Manuel Justin G.; Ibarra, Daniel E.

doi:10.1016/j.ejrh.2022.101174

Cited by 1 publication

(2 citation statements)

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“…No station belongs to Type II, which has no dry season, with a very pronounced maximum rain from December to February. The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) and the national meteorological and hydrological services (NHMS) agency of the Philippines classify these four climate zones following the Modified Corona Climate Classification based on average monthly rainfall totals [21,46,47].…”

Section: Study Area and Preliminary Data Analysismentioning

confidence: 99%

“…There is also the influence on the inter-annual climatic variability of El Niño Southern Oscillation (ENSO), a largepattern atmospheric and ocean circulation process that triggers the fluctuation between above-normal (El Niño) and below normal (La Niña) sea surface temperature (SST) over the tropical Pacific [13][14][15]. These seasonal and inter-annual climatic variation adversely affected both the agricultural production [16][17][18], and water resources [19][20][21][22] in the country. In the case of Angat Watershed, the heavy rainfall during the wet season is crucial for replenishing the water supply in the Angat Reservoir [10], while during the dry season, rainfall variations over the watershed can have a significant impact on water availability and the risk of drought [19].…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal Analysis of Extreme Rainfall and Meteorological Drought Events over the Angat Watershed, Philippines

Tejada,

Sanchez,

Faderogao

et al. 2023

Atmosphere

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Understanding the spatiotemporal distribution of extreme rainfall and meteorological drought on a watershed scale could be beneficial for local management of any water resources system that supports dam operation and river conservation. This study considered the watershed of Angat as a case, given its economic importance in the Philippines. A series of homogeneity tests were initially conducted on each rainfall dataset from monitoring stations in and near the watershed, followed by trend analysis to determine the rate and direction of change in the annual and seasonal rainfall extreme indices in terms of intensity, duration, and frequency. Three indices, using the rainfall deviation method (%DEV), percent of normal rainfall index (PNRI), and Standardized Precipitation Index (SPI), were also used to identify meteorological drought events. Generally, rainfall in the watershed has an increasing annual PCPTOT (4–32 mm/year), with increasing frequency and intensity in heavy rainfall and wet days. A significant increasing trend (α = 5%) in the seasonal PCPTOT (7–65 mm/year) and R10mm (1.7–10.0 days/decade) was particularly observed in all stations during the Amihan Monsoon Season (Dec–Feb). The observed increasing rainfall intensity and frequency, if it continues in the future, could have an implication both for the water resources operation to satisfy the multiple objectives of Angat Reservoir and for the flood operation that prevents damage in the downstream areas. The effect of each ENSO (El Niño- Southern Oscillation) phase on the rainfall is unique in magnitude, intensity, and duration. The seasonal reversal of the ENSO in the extreme rainfall and meteorological drought signals in Angat Watershed was also evident. The identified meteorological drought events in the watershed based on SPI-12 persisted up to 12–33 months, could reduce more than 60% (PNRI < 40%) of the normal rainfall. Insights from the study have implications for the hydrology of the watershed that should be considered for the water resources management of the Angat Reservoir.

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Section: Study Area and Preliminary Data Analysismentioning

confidence: 99%