IOP Conference Series: Materials Science and Engineering
The hotspot of MODIS Aqua/Terra represents the high risk of land/forest fire due to an extreme te... more The hotspot of MODIS Aqua/Terra represents the high risk of land/forest fire due to an extreme temperature over the hotspot location. Spatial-temporal analysis of the hotspot can be used to map the regions with a high vulnerability of forest/land fires. This study has an objective to use hotspot data from MODIS Aqua/Terra to map the forest/land fires over the Humbang Hasudutan Regency from 2001 to 2019. In spatial, the hotspot mostly occurs in the eastern part of the study area (Doloksanggul and Pollung), which this area has assigned as the peatland area. Based on land cover, the hotspot often detected over the dryland agriculture, dryland with shrubs, and bare soil. In temporal, the hotspot mostly increases during the dry seasons such as February, June, and July. The hotspot decreases during the wet season, such as January, October, November, and December. Besides, there was an inversely proportional between the number of detected hotspots and rainfall over the study area.
Nowadays, Breaks for Additive Seasonal and Trend (BFAST) method based on time series of Moderate ... more Nowadays, Breaks for Additive Seasonal and Trend (BFAST) method based on time series of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data is increasingly used to monitor the temporal dynamics of vegetation changes. Nevertheless, sensitivity of the BFAST method for detecting the vegetation cover changes based on the choice of vegetation indices and land cover types has not been widely investigated. Breaks for Additive Seasonal and Trend (BFAST) method has applied to MODIS 16-day Enhance Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) composites images (2000-2014) of three land cover types (Urban and Built-Up, Evergreen Broadleaf Forest and Savannah) within Australia. Overall, the number and time of changes detected in the three land cover types differed with both time series data because of the data quality due to the cloud cover. As conclusion, the EVI is more sensitive than NDVI for detecting the seasonal and abrupt changes for the land c...
Tornado wind often occurs in Humbang Hasudutan (Humbahas), North Sumatra. Even though the map of ... more Tornado wind often occurs in Humbang Hasudutan (Humbahas), North Sumatra. Even though the map of tornado vulnerability has constructed by The National Agency for Disaster Countermeasure (BNPB), but several regions did not yet have this map due to limited observation data. This study’s objective is to map the vulnerability of tornado in Humbahas using satellite data where the satellite data has more significant quality in area coverage and time-series data. The Composite Mapping Analysis (CMA) has been used to model the vulnerability map. There were three factors has used in this model, such as rainfall, land cover, and slope. Based on the tornado vulnerability map, there was an 802,406.24 ha area (74.63%) in Humbahas, classified as “high” risk to Tornado disaster. There was 271,945.46 ha (25.29%), which assigned as “moderate” risk. About 786.51 ha (0.07%) of the Humbahas area has a “low” risk of tornado disaster. As a result, the study area has a “moderate” to “high” risk of tornado wind disaster, then the adaption and mitigation plans need to be done in handling tornado hazard in this region.
This study aims to explore the contrasting characteristics of large-scale circulation that led to... more This study aims to explore the contrasting characteristics of large-scale circulation that led to the precipitation anomalies over the northern parts of Sumatra Island. Further, the impact of varying the Asian–Australian Monsoon (AAM) was investigated for triggering the precipitation variability over the study area. The moisture budget analysis was applied to quantify the most dominant component that induces precipitation variability during the JJA (June, July, and August) period. Then, the composite analysis and statistical approach were applied to confirm the result of the moisture budget. Using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Anaysis Interim (ERA-Interim) from 1981 to 2016, we identified 9 (nine) dry and 6 (six) wet years based on precipitation anomalies, respectively. The dry years (wet years) anomalies over the study area were mostly supported by downward (upward) vertical velocity anomaly instead of other variables such as specific humidity, h...
ABSTRACT Radar Cuaca Doppler C-band (CDR) telah dioperasikan di Balai Besar Meteorologi Klimatolo... more ABSTRACT Radar Cuaca Doppler C-band (CDR) telah dioperasikan di Balai Besar Meteorologi Klimatologi dan Geofisika Wilayah I (BBMKG Wilayah I) sejak 08 April 2010. Sebagai sebuah sistem yang berorientasi pada sebuah tujuan maka perlu dilakukan evaluasi terhadap kemampuan dan sensitivitas radar cuaca di BBMKG Wilayah I dalam mendeteksi adanya fenomena perubahan cuaca khusunya untuk fenomena cuaca yang jauh dari sumber radar dan berada pada topografi yang tinggi. Sebagai studi kasus dalam mengevaluasi sensitivitas radar cuaca BBMKG Wilayah I, maka telah dilakukan analisa kejadian angin puting beliung pada tanggal 29 Januari 2013 di kecamatan siborongborong, kabupaten tapanuli utara, propinsi sumatera utara. Dengan menggunakan produk turunan data radar cuaca CDR yaitu CAPPI (Constant Altitude Plan Position Indicator), PPI (Plan Position Indicator), VIL (Vertical Integrated Liquid Water Content), Storm Track serta divalidasi dengan menggunakan Citra satelit MTSAT (Multi-functional Transport Satellites), Radar Cuaca Doppler C-band (CDR) di BBMKG Wilayah I terbukti mampu dan sensitif dalam mendeteksi kejadian angin puting beliung di kecamatan siborongborong, tapanuli utara yang terletak kurang lebih 145 km dari sumber radar (Medan).
Remotely sensed vegetation indices (VI) such as the Normalized Difference Vegetation Index (NDVI)... more Remotely sensed vegetation indices (VI) such as the Normalized Difference Vegetation Index (NDVI) are increasingly used as a proxy indicator of the state and condition of the land cover/vegetation, including forest. However, the Enhanced Vegetation Index (EVI) on the outcome of forest change detection has not been widely investigated. We compared the influence of using EVI and NDVI on the number and time of detected changes by applying Breaks for Additive Seasonal and Trend (BFAST), a change detection algorithm. We used MODIS 16-day NDVI and EVI composite images (April 2000-April 2012) of three pixels (pixels 352, 378, and 380) in the tropical peat swamp forest area around the flux tower of Palangka Raya, Central Kalimantan. The results of BFAST method were compared to the Normalized Difference Fraction Index (NDFI) maps and the maps were validated by the hotspot of the Infrastructure and Operational MODIS-Based Near Real-Time Fire (INDOFIRE). Overall, the number and time of changes...
The scarcity of groundwater and precipitation stations has limited accurate assessments of basin-... more The scarcity of groundwater and precipitation stations has limited accurate assessments of basin-scale groundwater systems. This study proposes a workflow that integrates satellite and on-site observations to improve the spatial and temporal resolution of the groundwater level and enable recharge estimations for the Choushui River groundwater basin (CRGB) in Western Taiwan. The workflow involves multiple data processing steps, including analysis of correlation, evaluation of residuals, and geostatistical interpolation based on kriging methods. The observed groundwater levels and recharge are then the basis to assess spatial-temporal interactions between groundwater and recharge in the CRGB from 2006 to 2015. Results of correlation analyses show the high correlation between the groundwater level and the land surface elevation in the study area. However, the multicollinearity problem exists for the additional precipitation data added in the correlation analyses. The correlation coefficient, root mean square error, and normalized root mean square parameters indicate that the Regression Kriging (RK) performs better the groundwater variations than the Ordinary Kriging (OK) dose. The data-driven approach estimates an annual groundwater recharge of approximately 1.40 billion tons, representing 37% of the yearly precipitation. The correlation between groundwater levels and groundwater recharge exhibits low or negative correlation zones in the groundwater basin. These zones might have resulted from multipurpose pumping activities and the river and drainage networks in the area. The event-based precipitation and groundwater level have shown strong recharge behavior in the low-land area of the basin. Artificial weir operations at the highland mountain pass might considerably influence the groundwater and surface water interactions.
IOP Conference Series: Materials Science and Engineering
The hotspot of MODIS Aqua/Terra represents the high risk of land/forest fire due to an extreme te... more The hotspot of MODIS Aqua/Terra represents the high risk of land/forest fire due to an extreme temperature over the hotspot location. Spatial-temporal analysis of the hotspot can be used to map the regions with a high vulnerability of forest/land fires. This study has an objective to use hotspot data from MODIS Aqua/Terra to map the forest/land fires over the Humbang Hasudutan Regency from 2001 to 2019. In spatial, the hotspot mostly occurs in the eastern part of the study area (Doloksanggul and Pollung), which this area has assigned as the peatland area. Based on land cover, the hotspot often detected over the dryland agriculture, dryland with shrubs, and bare soil. In temporal, the hotspot mostly increases during the dry seasons such as February, June, and July. The hotspot decreases during the wet season, such as January, October, November, and December. Besides, there was an inversely proportional between the number of detected hotspots and rainfall over the study area.
Nowadays, Breaks for Additive Seasonal and Trend (BFAST) method based on time series of Moderate ... more Nowadays, Breaks for Additive Seasonal and Trend (BFAST) method based on time series of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data is increasingly used to monitor the temporal dynamics of vegetation changes. Nevertheless, sensitivity of the BFAST method for detecting the vegetation cover changes based on the choice of vegetation indices and land cover types has not been widely investigated. Breaks for Additive Seasonal and Trend (BFAST) method has applied to MODIS 16-day Enhance Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) composites images (2000-2014) of three land cover types (Urban and Built-Up, Evergreen Broadleaf Forest and Savannah) within Australia. Overall, the number and time of changes detected in the three land cover types differed with both time series data because of the data quality due to the cloud cover. As conclusion, the EVI is more sensitive than NDVI for detecting the seasonal and abrupt changes for the land c...
Tornado wind often occurs in Humbang Hasudutan (Humbahas), North Sumatra. Even though the map of ... more Tornado wind often occurs in Humbang Hasudutan (Humbahas), North Sumatra. Even though the map of tornado vulnerability has constructed by The National Agency for Disaster Countermeasure (BNPB), but several regions did not yet have this map due to limited observation data. This study’s objective is to map the vulnerability of tornado in Humbahas using satellite data where the satellite data has more significant quality in area coverage and time-series data. The Composite Mapping Analysis (CMA) has been used to model the vulnerability map. There were three factors has used in this model, such as rainfall, land cover, and slope. Based on the tornado vulnerability map, there was an 802,406.24 ha area (74.63%) in Humbahas, classified as “high” risk to Tornado disaster. There was 271,945.46 ha (25.29%), which assigned as “moderate” risk. About 786.51 ha (0.07%) of the Humbahas area has a “low” risk of tornado disaster. As a result, the study area has a “moderate” to “high” risk of tornado wind disaster, then the adaption and mitigation plans need to be done in handling tornado hazard in this region.
This study aims to explore the contrasting characteristics of large-scale circulation that led to... more This study aims to explore the contrasting characteristics of large-scale circulation that led to the precipitation anomalies over the northern parts of Sumatra Island. Further, the impact of varying the Asian–Australian Monsoon (AAM) was investigated for triggering the precipitation variability over the study area. The moisture budget analysis was applied to quantify the most dominant component that induces precipitation variability during the JJA (June, July, and August) period. Then, the composite analysis and statistical approach were applied to confirm the result of the moisture budget. Using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Anaysis Interim (ERA-Interim) from 1981 to 2016, we identified 9 (nine) dry and 6 (six) wet years based on precipitation anomalies, respectively. The dry years (wet years) anomalies over the study area were mostly supported by downward (upward) vertical velocity anomaly instead of other variables such as specific humidity, h...
ABSTRACT Radar Cuaca Doppler C-band (CDR) telah dioperasikan di Balai Besar Meteorologi Klimatolo... more ABSTRACT Radar Cuaca Doppler C-band (CDR) telah dioperasikan di Balai Besar Meteorologi Klimatologi dan Geofisika Wilayah I (BBMKG Wilayah I) sejak 08 April 2010. Sebagai sebuah sistem yang berorientasi pada sebuah tujuan maka perlu dilakukan evaluasi terhadap kemampuan dan sensitivitas radar cuaca di BBMKG Wilayah I dalam mendeteksi adanya fenomena perubahan cuaca khusunya untuk fenomena cuaca yang jauh dari sumber radar dan berada pada topografi yang tinggi. Sebagai studi kasus dalam mengevaluasi sensitivitas radar cuaca BBMKG Wilayah I, maka telah dilakukan analisa kejadian angin puting beliung pada tanggal 29 Januari 2013 di kecamatan siborongborong, kabupaten tapanuli utara, propinsi sumatera utara. Dengan menggunakan produk turunan data radar cuaca CDR yaitu CAPPI (Constant Altitude Plan Position Indicator), PPI (Plan Position Indicator), VIL (Vertical Integrated Liquid Water Content), Storm Track serta divalidasi dengan menggunakan Citra satelit MTSAT (Multi-functional Transport Satellites), Radar Cuaca Doppler C-band (CDR) di BBMKG Wilayah I terbukti mampu dan sensitif dalam mendeteksi kejadian angin puting beliung di kecamatan siborongborong, tapanuli utara yang terletak kurang lebih 145 km dari sumber radar (Medan).
Remotely sensed vegetation indices (VI) such as the Normalized Difference Vegetation Index (NDVI)... more Remotely sensed vegetation indices (VI) such as the Normalized Difference Vegetation Index (NDVI) are increasingly used as a proxy indicator of the state and condition of the land cover/vegetation, including forest. However, the Enhanced Vegetation Index (EVI) on the outcome of forest change detection has not been widely investigated. We compared the influence of using EVI and NDVI on the number and time of detected changes by applying Breaks for Additive Seasonal and Trend (BFAST), a change detection algorithm. We used MODIS 16-day NDVI and EVI composite images (April 2000-April 2012) of three pixels (pixels 352, 378, and 380) in the tropical peat swamp forest area around the flux tower of Palangka Raya, Central Kalimantan. The results of BFAST method were compared to the Normalized Difference Fraction Index (NDFI) maps and the maps were validated by the hotspot of the Infrastructure and Operational MODIS-Based Near Real-Time Fire (INDOFIRE). Overall, the number and time of changes...
The scarcity of groundwater and precipitation stations has limited accurate assessments of basin-... more The scarcity of groundwater and precipitation stations has limited accurate assessments of basin-scale groundwater systems. This study proposes a workflow that integrates satellite and on-site observations to improve the spatial and temporal resolution of the groundwater level and enable recharge estimations for the Choushui River groundwater basin (CRGB) in Western Taiwan. The workflow involves multiple data processing steps, including analysis of correlation, evaluation of residuals, and geostatistical interpolation based on kriging methods. The observed groundwater levels and recharge are then the basis to assess spatial-temporal interactions between groundwater and recharge in the CRGB from 2006 to 2015. Results of correlation analyses show the high correlation between the groundwater level and the land surface elevation in the study area. However, the multicollinearity problem exists for the additional precipitation data added in the correlation analyses. The correlation coefficient, root mean square error, and normalized root mean square parameters indicate that the Regression Kriging (RK) performs better the groundwater variations than the Ordinary Kriging (OK) dose. The data-driven approach estimates an annual groundwater recharge of approximately 1.40 billion tons, representing 37% of the yearly precipitation. The correlation between groundwater levels and groundwater recharge exhibits low or negative correlation zones in the groundwater basin. These zones might have resulted from multipurpose pumping activities and the river and drainage networks in the area. The event-based precipitation and groundwater level have shown strong recharge behavior in the low-land area of the basin. Artificial weir operations at the highland mountain pass might considerably influence the groundwater and surface water interactions.
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