In south Meghalaya, farmers maintain a variety of economically important plant species in arecanut agroforestry systems. We investigated plant species composition of arecanut agroforests of south Meghalaya and encount...In south Meghalaya, farmers maintain a variety of economically important plant species in arecanut agroforestry systems. We investigated plant species composition of arecanut agroforests of south Meghalaya and encountered 160 plants, which included 83 tree species, 22 shrub species, 41 herb species and 14 climber species. The study reveals that arecanut agroforests provide cash income, medicine, timber, fuelwood and edibles for household consumption as well as for sale. We conclude that these agroforestry systems serve as home for many economically important plant species, harbour rich biodiversity and mimic the natural forests both in structural composition as well as ecological and economic functions.展开更多
This study utilizes ML classifiers to estimate canopy density based on three decades of data (1990-2021). The Support Vector Machine (SVM) classifier outperformed other classifiers, such as Random Tree and Maximum Lik...This study utilizes ML classifiers to estimate canopy density based on three decades of data (1990-2021). The Support Vector Machine (SVM) classifier outperformed other classifiers, such as Random Tree and Maximum Likelihood. Satellite data from Landsat and Sentinel 2 was classified using a developed python model, providing an economical and time-saving approach. The accuracy of the classification was evaluated through a confusion matrix and area computation. The findings indicate a negative trend in the overall decadal change, with significant tree loss attributed to jhum cultivation, mining, and quarry activities. However, positive changes were observed in recent years due to the ban on illegal mining. The study highlights the dynamic nature of tree cover and emphasizes the need for biennial assessments using at least five time-series data. Micro-level analysis in Shallang, West Khasi hills, revealed a concerning trend of shortening jhum cycles. Automation in canopy change analysis is crucial for effective forest monitoring, providing timely information for law enforcement proposals and involving forest managers, stakeholders, and watchdog organizations.展开更多
The investigation of extreme weather phenomena is an important scientific field that incorporates multiple disciplines due to their significant impacts on various sectors and society as a whole.There is evidence to su...The investigation of extreme weather phenomena is an important scientific field that incorporates multiple disciplines due to their significant impacts on various sectors and society as a whole.There is evidence to support the occurrence of severe weather events in different regions of the world.In India,major precipitation events,such as the Mumbai floods in 2005 and the Kerala floods in 2018,often occur during the south-west monsoon season,leading to significant impacts.This statement is also applicable to states like Arunachal Pradesh,Nagaland,and Manipur in the northeast region.Intense precipitation events caused significant impacts in Meghalaya from June 16th to June 18th,2022.These events resulted in a significant socio-economic and human impact,including infrastructure damage,displacement of communities,and around 90 reported fatalities in Assam and Meghalaya.These two states are susceptible to flooding and erosion,and they consistently face intense and periodic floods on an annual basis.Analysis of the 2022 rainfall data reveals that over 4.8 million individuals were adversely impacted in the majority of districts in Assam and Meghalaya.Specifically,79%of the total 43 districts were affected.This study analyzed the meteorological aspects of exceptional heavy rainfall events in Meghalaya from June 16th to 18th,2022,to understand their significant impact on the environment and society.The extreme weather event in Meghalaya was a result of a well-marked low pressure area,a significant influx of moisture from the Bay of Bengal(BoB),favourable dynamics and thermodynamics conditions,and a supportive cloud top temperature(CTT)that collectively intensified the heavy rainfall.The study's findings can provide valuable insights for disaster managers and forecasters,enabling them to better prepare for and respond to extreme rainfall events in the northeast region of the country.展开更多
Palaeocene-Eocene carbonates of shallow marine sequence belonging to Shella Formation of Jaintia Group are well developed in the south of the Jaintia Hills, Meghalaya and represent an excellent outcrop of shelf sedime...Palaeocene-Eocene carbonates of shallow marine sequence belonging to Shella Formation of Jaintia Group are well developed in the south of the Jaintia Hills, Meghalaya and represent an excellent outcrop of shelf sediments in North Eastern Himalaya, India. These outcrops are exposed along the southern fringe of Shillong Plateau. The Prang Limestone is the uppermost lithostratigraphic unit of the Shella Formation within the Jaintia Group. It is overlain by sand-shale alternation of the Kopili Formation and underlain by the Narpuh Sandstone. A rich assemblage of larger foraminifera including Nummulites, Discocyclina etc. has been recorded earlier from the Prang Limestone and based on the foraminiferal assemblage, a Middle Eocene to Early Late Eocene age has been assigned to the Prang Limestone. Thin section analysis of the Prang Limestone revealed the abundance of well preserved coralline red algae along with other well preserved and significant biogenic elements. Morpho-taxonomical study reveals that the algal flora is represented by seven species belonging to the families Hapalidiaceae(Subfamily: Melobesioideae), Corallinaceae(Subfamily: Mastophoroideae) and Sporolithaceae. The dominance of melobesioid and mastophoroid forms is the characteristic feature of this algal assemblage. Coralline algae occur mostly in encrusting growth form with orbitoid foraminifera and occasionally the coralline algae form rhodoliths. On this basis of algal forms it can be inferred that they thrived in a shallow, warm, shelf environment of normal salinity.展开更多
The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coa...The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation.The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank.The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank coals.Moreover,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal metamorphism.The Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification jump.Besides,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature hydrocarbons.However,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon potential.Meanwhile,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.展开更多
文摘In south Meghalaya, farmers maintain a variety of economically important plant species in arecanut agroforestry systems. We investigated plant species composition of arecanut agroforests of south Meghalaya and encountered 160 plants, which included 83 tree species, 22 shrub species, 41 herb species and 14 climber species. The study reveals that arecanut agroforests provide cash income, medicine, timber, fuelwood and edibles for household consumption as well as for sale. We conclude that these agroforestry systems serve as home for many economically important plant species, harbour rich biodiversity and mimic the natural forests both in structural composition as well as ecological and economic functions.
文摘This study utilizes ML classifiers to estimate canopy density based on three decades of data (1990-2021). The Support Vector Machine (SVM) classifier outperformed other classifiers, such as Random Tree and Maximum Likelihood. Satellite data from Landsat and Sentinel 2 was classified using a developed python model, providing an economical and time-saving approach. The accuracy of the classification was evaluated through a confusion matrix and area computation. The findings indicate a negative trend in the overall decadal change, with significant tree loss attributed to jhum cultivation, mining, and quarry activities. However, positive changes were observed in recent years due to the ban on illegal mining. The study highlights the dynamic nature of tree cover and emphasizes the need for biennial assessments using at least five time-series data. Micro-level analysis in Shallang, West Khasi hills, revealed a concerning trend of shortening jhum cycles. Automation in canopy change analysis is crucial for effective forest monitoring, providing timely information for law enforcement proposals and involving forest managers, stakeholders, and watchdog organizations.
文摘The investigation of extreme weather phenomena is an important scientific field that incorporates multiple disciplines due to their significant impacts on various sectors and society as a whole.There is evidence to support the occurrence of severe weather events in different regions of the world.In India,major precipitation events,such as the Mumbai floods in 2005 and the Kerala floods in 2018,often occur during the south-west monsoon season,leading to significant impacts.This statement is also applicable to states like Arunachal Pradesh,Nagaland,and Manipur in the northeast region.Intense precipitation events caused significant impacts in Meghalaya from June 16th to June 18th,2022.These events resulted in a significant socio-economic and human impact,including infrastructure damage,displacement of communities,and around 90 reported fatalities in Assam and Meghalaya.These two states are susceptible to flooding and erosion,and they consistently face intense and periodic floods on an annual basis.Analysis of the 2022 rainfall data reveals that over 4.8 million individuals were adversely impacted in the majority of districts in Assam and Meghalaya.Specifically,79%of the total 43 districts were affected.This study analyzed the meteorological aspects of exceptional heavy rainfall events in Meghalaya from June 16th to 18th,2022,to understand their significant impact on the environment and society.The extreme weather event in Meghalaya was a result of a well-marked low pressure area,a significant influx of moisture from the Bay of Bengal(BoB),favourable dynamics and thermodynamics conditions,and a supportive cloud top temperature(CTT)that collectively intensified the heavy rainfall.The study's findings can provide valuable insights for disaster managers and forecasters,enabling them to better prepare for and respond to extreme rainfall events in the northeast region of the country.
文摘Palaeocene-Eocene carbonates of shallow marine sequence belonging to Shella Formation of Jaintia Group are well developed in the south of the Jaintia Hills, Meghalaya and represent an excellent outcrop of shelf sediments in North Eastern Himalaya, India. These outcrops are exposed along the southern fringe of Shillong Plateau. The Prang Limestone is the uppermost lithostratigraphic unit of the Shella Formation within the Jaintia Group. It is overlain by sand-shale alternation of the Kopili Formation and underlain by the Narpuh Sandstone. A rich assemblage of larger foraminifera including Nummulites, Discocyclina etc. has been recorded earlier from the Prang Limestone and based on the foraminiferal assemblage, a Middle Eocene to Early Late Eocene age has been assigned to the Prang Limestone. Thin section analysis of the Prang Limestone revealed the abundance of well preserved coralline red algae along with other well preserved and significant biogenic elements. Morpho-taxonomical study reveals that the algal flora is represented by seven species belonging to the families Hapalidiaceae(Subfamily: Melobesioideae), Corallinaceae(Subfamily: Mastophoroideae) and Sporolithaceae. The dominance of melobesioid and mastophoroid forms is the characteristic feature of this algal assemblage. Coralline algae occur mostly in encrusting growth form with orbitoid foraminifera and occasionally the coralline algae form rhodoliths. On this basis of algal forms it can be inferred that they thrived in a shallow, warm, shelf environment of normal salinity.
文摘The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation.The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank.The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank coals.Moreover,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal metamorphism.The Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification jump.Besides,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature hydrocarbons.However,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon potential.Meanwhile,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.
