Wyniki wyszukiwania - BazTech

1

Latent Heat Fluxes Trend and their Response to El Niño Southern Oscillation at the Global Scale

As-Syakur Abd. Rahman

Ecological Engineering & Environmental Technology

|

2024

|

Vol. 25, iss. 9

328--335

EN

This study employed the Japanese Ocean flux data sets with use of remote sensing observations version 2 (JOFURO2) to examine global-scale seasonal variations and trends in Latent heat flux (LHF) over a 19-year period. Furthermore, additional analysis has been conducted to determine the response of LHF to the El Niño Southern Oscillation (ENSO) phenomenon. To assess variability, trends, and strength of relationships with ENSO, statistical score analysis was employed using seasonal means, standard deviations, linear trends, and linear correlations, respectively. In this study, the seasons were classified as December-January-February (DJF), March-April-May (MAM), June-July-August (JJA), and September-October-November (SON). The result of the study revealed that the highest LHF values tracked the annual movement of the sun. In the Northern Hemisphere, the highest spatial trends occurred during DJF, while JJA exhibited the peak values in the Southern Hemisphere. This spatial pattern aligns with the seasonal means of LHF, where the highest and lowest standard deviations and trends coincide with the corresponding regions of high and low LHF. This finding suggests that the standard deviation patterns support the observed variability in seasonal LHF means. The strongest spatial correlations between LHF and ENSO were observed over the Indian Ocean during the SON season. In contrast, the correlations between LHF and ENSO in the Atlantic Ocean exhibited spatial heterogeneity, with a significant correlation only during the DJF season. In general, the seasonal spatio-temporal patterns suggest a dynamic link between LHF and ENSO, potentially linked to large-scale monsoon system changes, the specific locations and distributions of positive/negative trends and standard deviations in LHF reveal a spatial response that appears independent of the ENSO phenomenon.

2

Comparison of Soil Carbon-Nitrogen Ratio at Two Different Mangrove Ecosystem in Bali, Indonesia

Ernawati Ni Made, Astarini Ida Ayu, Suarna I Wayan, As-Syakur Abd. Rahman, Perwira Ima Yudha, Dewi Ayu Putu Wiweka Krisna, Sugiana I Putu

Ecological Engineering & Environmental Technology

|

2024

|

Vol. 25, iss. 7

343--354

EN

The mangrove ecosystem significantly contributes to nutrient and carbon exchange. It is primarily stored in the soil as organic matter, significantly benefiting the surrounding organisms. However, it could be changed depending on its surrounding conditions. This research aimed to determine the percentage of soil carbon-nitrogen and its ratio in two mangrove ecosystems, one with high anthropogenic impact (Tahura Ngurah Rai) and the other on a small island (Lembongan Island). We collect soil samples on 14 plots at each station at 0–30 cm depth and use carbon titration and TN-Kjeldahl methods for soil carbon-nitrogen measurement. The result shows substantial disparities in soil carbon levels between these ecosystems, but the soil nitrogen content was comparable. Two specific plots at Tahura Ngurah Rai (T8 and T11) were found at low soil carbon levels due to the damage to the mangrove forest. The C/N values vary between stations, primarily because of their different sources (Tahura Ngurah Rai: human activities, Lembongan: marine organisms). The C/N value at Tahura Ngurah Rai is higher than the Redfield ratios, while Lembongan Island is on the contrary. However, its levels at both stations are still categorized as common conditions for mangrove ecosystems compared to various sites in Indonesia. Future research will involve measuring radioisotope characteristics to verify the origin of nutrients in these ecosystems. Obtaining measurements of environmental parameters is also necessary to provide a more comprehensive explanation of the results.

3

Carbon Stocks Dynamics of Urban Green Space Ecosystems Using Time-Series Vegetation Indices

Sudarma I Made, Saifulloh Moh, Diara I Wayan, As-Syakur Abd. Rahman

Ecological Engineering & Environmental Technology

|

2024

|

Vol. 25, iss. 9

147--162

EN

The quantification of carbon stocks has emerged as a critical global issue due to its vital role in ecosystem services amid increasing urbanization and the impacts of global climate change. This study assesses carbon stocks in urban green space (UGS) ecosystems using time-series remote sensing data from 2014 to 2022. Carbon stock computation was derived from vegetation indices obtained from Landsat 8 satellite sensors, specifically the red and near infrared (NIR) bands with central wavelengths of 0.665 µm and 0.705 µm, respectively. The results, based on nine years of annual data, indicate a 24% increase in carbon stocks within UGS ecosystems. However, year-to-year transitions showed significant fluctuations, with a 19% decrease in carbon stocks from 2017 to 2019, and notable increases of 25% and 40% during the 2015–2016 and 2019–2020 periods, respectively. Spatially, carbon stock fluctuations were most pronounced in agricultural ecosystems, which are vulnerable to climate change, especially during El Niño-Southern Oscillation (ENSO) and positive Indian Ocean Dipole (IOD) events that influenced vegetation dynamics, particularly in low-density areas. The most substantial contributors to carbon stocks, exhibiting relatively stable and adaptive patterns to climate change, were mangrove and urban forest ecosystems. From a state-of-the-art perspective, this research addresses a gap in the literature where previous studies focused on calculating carbon for specific periods using various model approaches. Our implementation of a new time series analysis demonstrates that carbon stocks are dynamic, as evidenced by our findings. The results underscore the importance of preserving urban forest ecosystems, which play a significant role in climate change mitigation and the reduction of urban greenhouse gas emissions.