scholarly journals Impact Assessment of PSBB on Variations of NO2, CO, and Chlorophyll-a Concentration in Java Island during the COVID-19 Pandemic based on Multi-satellite Imagery Data

2021 ◽  
Vol 6 (2) ◽  
pp. 107
Author(s):  
Mochamad Riam Badriana ◽  
Hanif Diastomo ◽  
Avrionesti Avrionesti ◽  
Martin Yahya Surya ◽  
Umar Abdurrahman ◽  
...  

The enactment of the PSBB (Large-scale Social Restriction) on April to May 2020 due to COVID-19 pandemic, has reduced residents’ activities, especially in Java Island, the most populous area in Indonesia with high anthropological activities. This policy may affect the conditions of atmospheric and water environment around the island of Java. NO<sub>2</sub> and CO concentrations in atmosphere along with chlorophyll-a concentrationin the ocean are environmental indicators that can be observed through satellite imagery. Satellite data TROPOMI and CMEMS were used to investigate the variation of those concentrations in the atmosphere and ocean during PSBB. Oceanographic and atmospheric daily data of each parameter over the Java Island region were retrieved and merged into gridded data with 1 km spatial resolution to be compared. Variations of chlorophyll-a concentration within the same month over the previous years were also taken into account. NO<sub>2</sub>, CO, and chlorophyll-a concentration were fluctuating during the PSBB period, but tended to decrease in the early phase of PSBB.The higher concentration of chlorophyll-a concentrated in the northern coastal areas of Java Island. In Jakarta and Surabaya, chlorophyll-a concentrations value during April-May 2020 were decreased by 48% and 27% compared to the previous three years’ averages. Human activities were thought to be the main factor influencing variations in the concentration of NO<sub>2</sub>, CO, and chlorophyll-a during PSBB enactment

2021 ◽  
Vol 324 ◽  
pp. 01007
Author(s):  
Yulius Yulius ◽  
Vaninda Aidina ◽  
Muhammad Ramdhan ◽  
August Daulat

The fishing ground is identical and closely related to chlorophyll-a abundance in the waters, associated with its fisheries potential. This research has been conducted to determine the concentration and distribution of chlorophyll-a in the seas, especially in the Fisheries Management Area (FMA) 712 encompassing the Java Sea. The analysis used monthly time-series data collected from the satellite imagery over the last 11 years, taken through the ERDDAP website. The mean concentration of chlorophyll-a in the study area was 1.13 mg/l in June 2013. Based on 11 years of data processing, it can be concluded that the highest concentration of chlorophyll-a occurred in the west monsoon season from November to April, where increased rainfall caused the nutrient wash from terrestrial to the open waters. The lowest chlorophyll-a concentration happened in the east monsoon season from April to November, where the dry season arrived. The existence of pelagic fishes in FMA 712, such as Sardinella Lemurs and Sardinella Fimbriata, in waters highly influenced by the chlorophyll-a concentration, while Thunnus Sp. and Exocoetidae Sp. not affected significantly to the existence of chlorophyll-a concentration and its distribution.


Author(s):  
J. LUMBAN GAOL ◽  
WUDIANTO ◽  
B. P. PASARIBU ◽  
D. MANURUNG ◽  
R. ENDRIANI

The investigation is aimed to know the relationship between chlorophyll-a (chl-a) concentration and the abundance of Oily sardine (Sardinella lemuru), in Bali Strait. A time series of monthly mean chl-a data derived from Ocean Color Thermal Scanner (OCTS) sensor and Sea-viewing Wide Field-of View Sensor (SeaWiFS) during 1997-1999 are used in this study. Monthly Sardinella lemuru catch during 1997-1999 are obtained from fish landing data. The abundance of Sardinella lemuru is determined from acoustic data conducted in Bali Strait in September 1998 and May 1999. The result shows that the fluctuation of chlorophyll-a concentration in Bali Strait is influenced by monsoon and global climate change phenomena such as Dipole Mode (DM) event. During southeast Monsoon the upwelling process occurred around Bali Strait, so that the chl-a concentration is increased and during DM event occurred positive anomaly of chl-a concentration. The catch of Sardinella lemuru in Bali Strait is fluctuated during 1997-1999. The correlation between chl-a concentration and lemuru catch is positive and significant with certain time lag. Key words: Chlorophyll-a, Sardinella lemuru, Bali Strait, Satellite imagery


Author(s):  
Alexander Gilerson ◽  
Mateusz Malinowski ◽  
Eder Herrera ◽  
Michelle C. Tomlinson ◽  
Richard P. Stumpf ◽  
...  

Author(s):  
H. L. Sun ◽  
H. C. He ◽  
B. L. Fu ◽  
S. W. Wang

Abstract. In order to meet the demand of obtaining chlorophyll a concentration distribution in the offshore waters of Hong Kong on a rapid and large scale, based on the daily measured chlorophyll a concentration data and the HJ-1A/B satellite multispectral data in 2009–2019. Taking Modis-Aqua and Himawari series chlorophyll a concentration of remote sensing products as comparative data. Through per-process to extracted the reflectivity of each band combined and statistical correlation analysis with measured data, select the highest correlation band combination as the characteristic variable to statistical regression analysis with two-thirds of the measured chlorophyll a concentration data, constructing multiple regression algorithms. Determination of the best inversion algorithm by verified accuracy of the remaining one-third of the measured data. Inversion of chlorophyll a concentration in the offshore waters of Hong Kong from 2009 to 2019, the results show: 1). The best inversion algorithm is a univariate cubic regression algorithm, R2 is 0.942, RMSE is 0.285 μg/L, RPD is 33%; 2). The overall trend of remote products is the same as the measured data, but the value is slightly higher than the measured data;3). The distribution characteristics in the offshore waters of Hong Kong in the recent ten years are “high in the east and low in the west”, and the average concentration in the western waters is about 5 μg/L lower than the eastern waters.


Author(s):  
Rayhan Nuris ◽  
Jonson Lumban Gaol ◽  
Teguh Prayogo

This study aimed to estimate the concentration of chlorophyll-a from satellite imagery of National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) in the south Java Sea waters and compare it to the concentrations of chlorophyll-a estimation result from the MODIS-Aqua satellite. NPP satellite had Visible/Infrared Imager Radiometer Suite (VIIRS) sensors which performance was same as Moderate Resolution Imaging Spectroradiometer (MODIS) sensor with a better spatial resolution. This study used daily satellite imagery of VIIRS-NPP for the period of September 2012 to August 2013. The algorithm that was used to estimate the concentration of chlorophyll-a was Ocean Color 3-band ratio (OC-3). The results showed that the spatial distribution pattern of chlorophyll-a concentration between VIIRS - NPP sensor and MODIS had the same pattern, but the estimation of chlorophyll-a concentration from the MODIS sensor was higher than VIIRS -NPP sensor. The concentration of chlorophyll-a showed that there were spatial and temporal variation in the south Java Sea waters. Generally, concentrations of chlorophyll-a was higher in East monsoon than West monsoon.


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