Leaf phenology and trunk growth of Avicennia alba (Blume) under a seasonally fluctuating saline environment in the tropical monsoon area of eastern Thailand

Climatically driven processes are important controls on the Earth’s surface and on interactions between the hydrological cycle and erosion in drainage basins. As a result, landscape forms such as hillslope topography can be used as an archive to reconstruct historical climatic conditions. Recent progress in the Structure-from-Motion (SfM) photogrammetric technique allows for the construction of high-resolution, low-cost topography data using remote-controlled unmanned aerial vehicle (UAV) surveys. Here, we present the climatic effects on the hillslope erosion rate that can be obtained from the drainage frequency of hillslopes. We quantify the centimeter-scale accuracy of surveys across 72 badland hillslopes in SE Taiwan, which is a tropical monsoon area with an annual precipitation of over 2 m. Our observations indicate that climatic erosion results in a higher drainage frequency and the number of furrows, instead of drainage density. Additionally, the morphometric slope index (MSI) has a strong positive correlation with erosion and its rate but shows a negative correlation with drainage length and a positive correlation with inclination. This suggests that the erosion pattern is due to gravitational mass wasting instead of hydrological erosion. MSI should always be calculated relying on the normalized slope length and is less applicable to landslide-dominated erosion. We, therefore, suggest that UAV-driven digital elevation models (DEMs) are integrated into erosion mapping to aid in identifying erosion patterns. We highlight the unique opportunity for cross-climate zone comparative studies offered by badland landscapes and differential rainfall patterns, with remote sensing techniques and the morphometric slope index.

Download Full-text

PEMETAAN HABITAT BENTIK INTERTIDAL: Informasi Awal Perencanaan Pengelolaan Pesisir Laut Secara Spasial di Bulak Setra dan Batu Karas, Kabupaten Pangandaran

Seminar Nasional Geomatika ◽

10.24895/sng.2017.2-0.403 ◽

2018 ◽

Vol 2 ◽

pp. 105

Author(s):

Rendra Pranata

Keyword(s):

Dissolved Oxygen ◽

Supervised Classification ◽

Landsat 7 ◽

Avicennia Alba

Ekosistem pesisir Kabupaten Pangandaran memiliki biodiversitas yang cukup tinggi, namun pasca-tsunami tahun 2006 terjadi penurunan kerapatan ekosistem mangrove akibat rusaknya daerah pesisir dan wilayah permukiman sepanjang 28 km. Penelitian ini bertujuan untuk mengetahui kondisi habitat bentik di kawasan intertidal seperti mangrove dan makrozoobentos, serta mengukur parameter kualitas air. Metode yang digunakan yaitu interpretasi citra Landsat 7 tahun 2017 dengan melakukan masking dan supervised classification untuk mengetahui daerah tutupan mangrove di Bulak Setra dan Batu Karas, kemudian dilakukan identifikasi mangrove dengan transek kuadran 10x10 meter sepanjang 50 meter ke arah laut pada 7 plot di Bulak Setra dan 14 plot di Batu Karas untuk validasi data citra satelit. Selain itu juga dilakukan pengukuran parameter kualitas air serta identifikasi makrozoobentos. Hasil penelitian menunjukkan bahwa mangrove di Bulak Setra didominasi oleh Scyphiphora hydrophyllacea dari 8 spesies lain yang ditemukan dengan Indeks Nilai Penting (INP) 94,41%, sedangkan di Batu Karas didominasi oleh Avicennia alba dari 8 spesies lain yang ditemukan dengan INP 157%. Nilai rata-rata parameter kualitas air di Bulak Setra dan Batu Karas berturut-turut yaitu suhu 30oC dan 29,41oC, salinitas 5,56 psu dan 27,23 psu, pH 7,48 dan 6,86 serta konsentrasi Dissolved Oxygen (DO) 5,2 dan 6,5 mg/L. Makrozoobentos didominasi oleh kelas Gastropoda. Faktor sosial ekonomi masyarakat juga disajikan sebagai informasi sumber daya manusia yang akan berperan menjadi komponen pembangunan pengelolaan pesisir. Diharapkan penelitian ini dapat menjadi informasi awal dalam pengelolaan perencanaan wilayah pesisir di Bulak Setra dan Batu Karas.Kata kunci: bentik, intertidal, mangrove

Download Full-text

RESEARCH PROGRESS OF ENVIRONMENTAL MECHANISMS FOR SPELEOTHEM δ18O IN ASIAN MONSOON AREA

Marine Geology & Quaternary Geology ◽

10.3724/sp.j.1140.2012.03155 ◽

2013 ◽

Vol 32 (3) ◽

pp. 155-162

Author(s):

Yaoqi HE ◽

Dianbing LIU ◽

Chao DENG

Keyword(s):

Asian Monsoon ◽

Research Progress ◽

Monsoon Area

Download Full-text

Tropical monsoon forest in Yunnan with comparison to the tropical rain forest

Chinese Journal of Plant Ecology ◽

10.3724/sp.j.1258.2011.00463 ◽

2011 ◽

Vol 35 (4) ◽

pp. 463-470 ◽

Cited By ~ 1

Author(s):

Hua ZHU

Keyword(s):

Rain Forest ◽

Tropical Rain Forest ◽

Monsoon Forest ◽

Tropical Monsoon ◽

Tropical Monsoon Forest

Download Full-text

Avicennia alba: Duke, N., Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S. & Miyagi, T.

IUCN Red List of Threatened Species ◽

10.2305/iucn.uk.2010-2.rlts.t178830a7620385.en ◽

2008 ◽

Author(s):

Keyword(s):

Avicennia Alba

Download Full-text

Investigation on thermal comfort of the uniform for workers in tropical monsoon climates

International Journal of Clothing Science and Technology ◽

10.1108/ijcst-07-2019-0104 ◽

2020 ◽

Vol 32 (6) ◽

pp. 849-868

Author(s):

Jingxian Xu ◽

Huijuan Liu ◽

Yunyi Wang ◽

Jun Li

Keyword(s):

Heat Transfer ◽

Thermal Comfort ◽

Dynamic Condition ◽

Thermal Manikin ◽

Content Type ◽

Wind Speeds ◽

Subjective Perceptions ◽

Tropical Monsoon ◽

Four Levels ◽

Thermal Insulations

PurposeThis study aims to investigate the heat transfer mechanism of the uniforms used by people working in hot, humid and windy environments. Furthermore, the effectiveness of an opening structure added to the armpit of the uniforms in improving thermal comfort was comparatively examined.Design/methodology/approachA set of uniforms was tested with the opening at the armpit alternatively zipped or unzipped. Thermal manikin and human tests were performed in a climatic chamber simulating the specific environmental conditions, including wind speeds at four levels (0.15, 0.5, 2, 4 m/s) and relative humidities at two levels (50 and 85%). Static and dynamic thermal insulations of clothing (IT) were examined by the thermal manikin tests. The human bodies' thermal responses, including heart rates (HR), eardrum temperatures (Te), skin temperatures (Tsk) and subjective perceptions, were given by the human tests.FindingsSpecial mechanisms of heat transfer in the specific uniforms used in tropical monsoon climates were revealed. Reductions on IT were caused by the movement of the human body and the environmental wind, and the empirical equations would underestimate this reduction. The opening at the armpit was able to prompt more heat transfer under dynamic condition, with reducing the IT by 11.8%, lowering the mean Tsk by 0.92°C, and significantly improving the subjective perceptions (p < 0.05). The heat exhaustion was alleviated with lowering the Te by 0.32°C.Originality/valueThis study managed to improve the thermal performance of uniforms for workers under unforgiving conditions. The evaluation and design methods introduced by this study provided practical guidance for similar products with strict dress codes and cost control requirements based on the findings from thorough product tests and analysis.

Download Full-text

Linking Holocene East Asian monsoon variability to solar forcing and ENSO activity: Multi-proxy evidence from a peatland in Northeastern China

The Holocene ◽

10.1177/0959683621994662 ◽

2021 ◽

pp. 095968362199466

Author(s):

Nannan Li ◽

Arash Sharifi ◽

Frank M Chambers ◽

Yong Ge ◽

Nathalie Dubois ◽

...

Keyword(s):

Asian Monsoon ◽

East Asian Monsoon ◽

Asian Summer Monsoon ◽

East Asian ◽

Northeastern China ◽

Solar Irradiation ◽

Enso Events ◽

Monsoon Area ◽

Wavelet Coherency ◽

Cross Wavelet

High-resolution proxy-based paleoenvironmental records derived from peatlands provide important insights into climate changes over centennial to millennial timescales. In this study, we present a composite climatic index (CCI) for the Hani peatland from northeastern China, based on an innovative combination of pollen-spore, phytolith, and grain size data. We use the CCI to reconstruct variations of the East Asian summer monsoon (EASM) intensity during the Holocene. This is accomplished with complete ensemble empirical mode decomposition (CEEMD), REDFIT, and cross-wavelet coherency analysis to reveal the periodicities (frequencies) of the multi-proxy derived CCI sequences and to assess potential external forcing of the EASM. The results showed that periodicities of ca. 300–350, 475, 600, 1075, and 1875 years were present in the Hani CCI sequence. Those periodicities are consistent with previously published periodicities in East Asia, indicating they are a product of external climate controls over an extensive region, rather than random variations caused by peatland-specific factors. Cross-wavelet coherency analysis between the decomposed CCI components and past solar activity reconstructions suggests that variations of solar irradiation are most likely responsible for the cyclic characteristics at 500-year frequency. We propose a conceptual model to interpret how the sun regulates the monsoon climate via coupling with oceanic and atmospheric circulations. It seems that slight solar irradiation changes can be amplified by coupling with ENSO events, which result in a significant impact on the regional climate in the East Asian monsoon area.

Download Full-text