Hiroyuki Hashiguchi, Hiroyuki
RISH Universitas Kyoto, Jepang

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Estimation of Raindrop Size Distribution Parameters Using Lightning Data over West Sumatra Salma, Faridah; Marzuki, Marzuki; Hashiguchi, Hiroyuki; Nauval, Fadli
Jurnal Ilmu Fisika Vol 13, No 2 (2021): Published in September 2021 (COMING ISSUE)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.13.2.92-100.2021

Abstract

In situ observations of raindrop size distributions (DSDs) are still limited, especially in the tropics. Therefore, this study develops an alternative method to calculate DSD parameters by utilizing lightning data from the World-Wide Lightning Location Network (WWLLN) observation. DSD data was obtained from Parsivel's observations in the equatorial regions of Indonesia, i.e., Kototabang (100.32◦E, 0.20◦S, 865 m above mean sea level/ASL), Padang (100.46°E, 0.915°S, 200 m ASL), and Sicincin (100.30°E, 0.546°S, 134 m ASL). A gamma distribution parameterized the DSD. Three analysis domains were examined, with a grid of 0.1° x 0.1°, 0.5° x 0.5°, and 1° x 1°.  We examined the possibility to calculate the near-instantaneous DSD parameter, so three short time intervals, namely, one, five and ten minutes, were used. The results showed that the number of lightning strokes does not adequately correlate with DSD parameters. This is observed in all time intervals and analysis domains. Thus, the use of lightning data to calculate DSD parameters is not possible for short time interval of DSD (near instantaneous DSD). However, lightning data can estimate the average DSD parameters for an average time of more than one hour, as recommended by previous studies.
Differences in Mechanisms of Orographic Rainfall over West Sumatra (Case Study: 10 April and 23 April 2004) Harjupa, Wendi; Shimomai, Toyoshi; Hashiguchi, Hiroyuki; Fujiyoshi, Yasushi; Kawashima, Masayuki
Jurnal Ilmu Fisika Vol 13, No 1 (2021): Published in March 2021
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.13.1.8-17.2021

Abstract

Two different mechanisms of orographic rainfall enhancement  in West Sumatra were investigated utilizing observed data during the Coupling Processes in the Equatorial Atmosphere (CPEA)-I campaign. The variation of the atmospheric conditions during the campaign was shown by rainfall, surface wind, humidity, and stability index. An X-band Doppler radar captured the atmospheric conditions related to the enhancement of orographic rainfall mechanisms. The dry and less stable atmospheric conditions resulted in the convective type of rainfall. In contrast, the humid and stable atmospheric conditions brought the large-scale rainfall in the mountainous region where the events took place coincided with the inactive and active MJO phases..
Comparison of Bright Band Radar from GPM and MRR Observation in West Sumatera Ramadhan, Ravidho; Marzuki, Marzuki; Vonnisa, Mutya; Harmadi, Harmadi; Hashiguchi, Hiroyuki; Shimomai, Toyoshi
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) 2021: Articles in Press
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v11n1.p%p

Abstract

AbstractThe Bright band (BB) measurement from NS scan on Global Precipitation Measurement (GPM) had been compared with Micro Rain Radar (MRR) which is installed in Kototabang, West Sumatera (0.23o S; 100.32oE; 865 m above sea level). The GPM data were collected from December 2014 to June 2018 and compared with MRR observation from January 2012 to August 2016. The BB values from these instruments were also compared with the values recommended by the International Telecommunication Union Recommendation (ITU-R) P.839. The BB from GPM and MRR shown slightly diurnal and seasonal variations. BB observations from GPM and MRR show good agreement with slightly difference in diurnal and seasonal variations. BB observations are more similar when the intensity of solar radiation is lower, ie at night (18.00-24.00 LT) until dawn (00.00-06.00 LT). Furthermore, MRR determined a slight bimodal pattern in the seasonal variation while GPM did not, it cause variation in observation of both instrument quite significant in seasonal variation. The largest different from the seasonal variation was observed in the summer season (Juni-August(JJA)). Moreover the measurement of the mean BB is still below the Freezing Height Level (FHL) value from ITU-R model, the measurement of both instruments obtained a high number than FHL considerably (>36 %). It showed the constant value for FHL in West Sumatera that would cause the attenuation estimation of microwaves to be less accurate.
Seasonal and Diurnal Variations of Lightning Activity Over West Sumatra and Its Correlation with Precipitation Type Saufina, Elfira; Marzuki, Marzuki; Vonnisa, Mutya; Hashiguchi, Hiroyuki; Harmadi, Harmadi
Makara Journal of Science Vol. 22, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Seasonal and diurnal variations of lightning activity over West Sumatra have been investigated using observations of Tropical Rainfall Measuring Mission–Lightning Imaging Sensor (TRMM–LIS) over a 16-year period. This study also used TRMM 3B43 and 2A25 data to observe the correlation between lightning activity with rainfall and precipitation type. Results show that lightning occurs more frequently over land than over ocean and coastal areas, in contrast to total rainfall, which is higher over ocean and coastalareas. The lightning pattern is similar to the convective rainfall (particularly deep convective) pattern, which indicates that the majority of lightning in West Sumatra is associated with deep convective rain. The lightning intensity in Indonesia during the convection period, namely, December–January–February and September–October–November, is higher than that during other periods. The diurnal cycle of lightning coincides with the diurnal cycle of cloud migration from the ocean to in land Sumatra, as reported in previous research. Lightning and deep convective precipitation are dominant during the day and evening (16.00–20.00 Local Standard Time [LST]), particularly over land. Stratiform precipitation occursmore frequentlyfrom afternoon to early morning (16.00–04.00 LST) over landand at 00.00–12.00 LST over the ocean.