Spatio-Temporal Estimation of Integrated Water Vapour Over the Malaysian Peninsula During Monsoon Season

Salihin, S.; Musa, Tajul Ariffin; Radzi, Zahira Mohd

doi:10.5194/isprs-archives-xlii-4-w5-165-2017

Cited by 3 publications

(1 citation statement)

References 5 publications

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“…The primary maximum is found in November, with the annual mean being 51.69 kgm −2 . This value is consistent with the 51.28 kg m −2 reported by [56], who deployed GPS measurements between 2011 and 2014 to evaluate IWV in Peninsular Malaysia. Except for the different annual mean values of IWV presented by each of the datasets, their oscillations are fairly synchronous throughout (Figure 4b).…”

Section: Temporal Variationsupporting

confidence: 90%

Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia

Makama

Lim

2020

Atmosphere

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Integrated water vapour (IWV) is the total amount of precipitable water in an atmospheric column between the Earth’s surface and space. The implication of its variability and trend on the Earth’s radiation budget and precipitation makes its monitoring on a regular basis important. ERA-Interim reanalysis (ERA) and radiosonde (RS) data from 1988 to 2018 were used to investigate variability and trend in IWV over Peninsular Malaysia. ERA performed excellently when gauged with RS. Trend analysis was performed using the non-parametric Mann–Kendall and Theil–Sen slope estimator tests. ERA and RS IWV revealed double fluctuations at the seasonal time scale, with maxima in May and November, which are the respective beginnings of the southwest monsoon (SWM) and northeast monsoon (NEM) seasons, as well as coincidental peaks of precipitation in the region. IWV decreased in a southeast–northwest orientation, with regional maximum domiciled over the southeastern tip of the region. Steep orography tended to shape intense horizontal gradients along the edges of the peninsular, with richer gradients manifesting along the western boundary during SWM, which harbours more water vapour in the peninsular. IWV trends, both at the annual and seasonal time series, were positive and statistically significant at the 95% level across the stations, except at Kota Bharu, where a nonsignificant downward trend manifested. Trends were mostly higher in the NEM, with the greatest rate being 0.20 ± 0.42 kgm−2 found at Penang. Overall, the IWV trend in Peninsular Malaysia was positive and consistent with the upward global changes in IWV reported elsewhere.

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Section: Temporal Variationsupporting

confidence: 90%

Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia

Makama

Lim

2020

Atmosphere

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Correcting Atmospheric Effects on the InSAR Measurements using GPS Data

Latip

Ansar²,

Din³

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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The effect of the atmospheric error in the spaceborne synthetic aperture radar (SAR) signal is more prominent in Malaysia due to its hot and wet conditions. Because the atmospheric error is believed to happen constantly in space and randomly in time, low-pass filtering in space and high-pass filtering in time is employed to measure it. However, with few scenes, the filtering technique’s reliability in removing atmospheric error may be insufficient, leading to erroneous surface deformation. Therefore, an external atmospheric correction needs to be modelled to improve the accuracy of surface deformation. In this study, the atmospheric error correction was estimated from GPS and applied to the deformation analysis. The result shows that the atmospheric error level estimated from the filtering technique was –6.9 to 7.5 radians, while using GPS was -1.0 to 1.9 radians. After using the filtering process, the rate of deformation fell dramatically. However, compared to the reference deformation, the rate was too low, indicating that the filtering technique overstated the level of atmospheric error. At many data collections, the atmospheric correction calculated from GPS gave deformation values closer to the reference deformation. Hence, this study will help the researchers to model the atmospheric correction over the Malaysia region in future.

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Inter-annual and seasonal patterns of precipitable water vapour over Malaysia from 1990-2019 based on MERRA-2 reanalysis

Makama

Lim

2021

srees

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In this study seasonal and inter-annual patterns as well as trend in the total precipitable water vapour (TPW) over Malaysia, based on a 30-year data from MERRA-2, have been evaluated using least square regression method. Indicator TPW revealed a pair of minima in February/August and maxima in May/November with highest and lowest long-term means found in East Malaysia. Long-term seasonal variability of TPW exhibited latitudinal dependency in both the NEM and SWM seasons. Indicator TPW showed respective southeast-northwest and southwest-northeast spatial distribution in West and East Malaysia, with the highest statistically significant positive trend found in the former.

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Spatio-Temporal Estimation of Integrated Water Vapour Over the Malaysian Peninsula During Monsoon Season

Cited by 3 publications

References 5 publications

Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia

Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia

Correcting Atmospheric Effects on the InSAR Measurements using GPS Data

Inter-annual and seasonal patterns of precipitable water vapour over Malaysia from 1990-2019 based on MERRA-2 reanalysis

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