Regional Trends and Spatial Gradients of Total Column Methane over India, China, and USA─Implications for Emissions from Coal Mining and Oil/Gas Exploitation.

Observation-based verification of regional/national methane (CH) emission trends is crucial for transparent monitoring and mitigation strategy planning. Although surface observations track the global and sub-hemispheric emission trends well, their sparse spatial coverage limits our ability to assess regional trends. Dense satellite observations complement surface observations, offering a valuable means to validate emission trends, especially in regions where emissions changes are substantial but debated.

CO variability over a tropical coastal station in India: Synergy of observation and model.

Carbon dioxide (CO), being the prime greenhouse gas, has largest contribution in radiative forcing and global warming due to increased anthropogenic emissions leading to regional and global climate change. We performed CO measurements using a continuous monitoring instrument at a tropical coastal station at the southern tip of India (Thumba; 8.54° N, 76.

Recent decline in carbon monoxide levels observed at an urban site in Ahmedabad, India.

Carbon monoxide (CO) is a prominent air pollutant in cities, with far-reaching implications for both local air quality and global atmospheric chemistry. The long-term change in atmospheric CO levels at a specific location is influenced by a complex interplay of local emissions, atmospheric transport, and photochemical processes, making it a subject of considerable interest. This study presents an 8-year analysis (2014-2021) of in situ CO observations using a cutting-edge laser-based analyzer at an urban site in Ahmedabad, western India.

Neighbouring effect of land use changes and fire emissions on atmospheric CO and CH over suburban region of India (Shadnagar).

The present study investigated the effects of land use/land cover (LU/LC) changes on atmospheric carbon dioxide (CO) and methane (CH) concentrations over the sub-urban region of India (Shadnagar) using continuous decadal CO and CHin-situ data measured by the greenhouse gas analyser (GGA). Data was collected from 2013 to 2022 at a 1 Hz frequency. Analysis of the current study indicates that during pre-monsoon, the seasonal maximum of CO was 409.

Revisiting regional and seasonal variations in decadal carbon monoxide variability: Global reversal of growth rate.

Carbon monoxide (CO) is one of the important trace gases in the atmosphere capturing the evolution of chemical properties of the troposphere. Here we analyze the growth rates of CO during the period of 1991-2020 using in situ measurements from the World Meteorological Organization's (WMO) Global Atmospheric Watch (GAW) program. The analysis of trends has been done on different spatial and temporal scales.

Very high particulate pollution over northwest India captured by a high-density in situ sensor network.

Exposure to particulate matter less than 2.5 µm in diameter (PM) is a cause of concern in cities and major emission regions of northern India. An intensive field campaign involving the states of Punjab, Haryana and Delhi national capital region (NCR) was conducted in 2022 using 29 Compact and Useful PM Instrument with Gas sensors (CUPI-Gs).

Advances in Structural Modifications and Properties of Graphene Quantum Dots for Biomedical Applications.

Graphene quantum dots (GQDs) are carbon-based, zero-dimensional nanomaterials and unique due to their astonishing optical, electronic, chemical, and biological properties. Chemical, photochemical, and biochemical properties of GQDs are intensely being explored for bioimaging, biosensing, and drug delivery. The synthesis of GQDs by top-down and bottom-up approaches, their chemical functionalization, bandgap engineering, and biomedical applications are reviewed here.

Observational constraints reduce model spread but not uncertainty in global wetland methane emission estimates.

The recent rise in atmospheric methane (CH ) concentrations accelerates climate change and offsets mitigation efforts. Although wetlands are the largest natural CH source, estimates of global wetland CH emissions vary widely among approaches taken by bottom-up (BU) process-based biogeochemical models and top-down (TD) atmospheric inversion methods. Here, we integrate in situ measurements, multi-model ensembles, and a machine learning upscaling product into the International Land Model Benchmarking system to examine the relationship between wetland CH emission estimates and model performance.

Near-real-time estimation of fossil fuel CO emissions from China based on atmospheric observations on Hateruma and Yonaguni Islands, Japan.

Unlabelled: We developed a near-real-time estimation method for temporal changes in fossil fuel CO (FFCO) emissions from China for 3 months [January, February, March (JFM)] based on atmospheric CO and CH observations on Hateruma Island (HAT, 24.06° N, 123.81° E) and Yonaguni Island (YON, 24.

Respiratory loss during late-growing season determines the net carbon dioxide sink in northern permafrost regions.

Warming of northern high latitude regions (NHL, > 50 °N) has increased both photosynthesis and respiration which results in considerable uncertainty regarding the net carbon dioxide (CO) balance of NHL ecosystems. Using estimates constrained from atmospheric observations from 1980 to 2017, we find that the increasing trends of net CO uptake in the early-growing season are of similar magnitude across the tree cover gradient in the NHL. However, the trend of respiratory CO loss during late-growing season increases significantly with increasing tree cover, offsetting a larger fraction of photosynthetic CO uptake, and thus resulting in a slower rate of increasing annual net CO uptake in areas with higher tree cover, especially in central and southern boreal forest regions.

Rotaxane nanomachines in future molecular electronics.

As the electronics industry is integrating more and more new molecules to utilize them in logic circuits and memories to achieve ultra-high efficiency and device density, many organic structures emerged as promising candidates either in conjunction with or as an alternative to conventional semiconducting materials such as but not limited to silicon. Owing to rotaxane's mechanically interlocked molecular structure consisting of a dumbbell-shaped molecule threaded through a macrocycle, they could be excellent nanomachines in molecular switches and memory applications. As a nanomachine, the macrocycle of rotaxane can move reversibly between two stations along its axis under external stimuli, resulting in two stable molecular configurations known as "ON" and "OFF" states of the controllable switch with distinct resistance.

Impact of Changing Winds on the Mauna Loa CO Seasonal Cycle in Relation to the Pacific Decadal Oscillation.

Long-term measurements at the Mauna Loa Observatory (MLO) show that the CO seasonal cycle amplitude (SCA) increased from 1959 to 2019 at an overall rate of 0.22   0.034 ppm decade while also varying on interannual to decadal time scales.

Methane sources from waste and natural gas sectors detected in Pune, India, by concentration and isotopic analysis.

Methane (CH) is a potent greenhouse gas and also plays a significant role in tropospheric chemistry. High-frequency (sub-hourly) measurements of CH and carbon isotopic ratio (δCH) have been conducted at Pune (18.53°N, 73.

Anthropogenic emission is the main contributor to the rise of atmospheric methane during 1993-2017.

Atmospheric methane (CH) concentrations have shown a puzzling resumption in growth since 2007 following a period of stabilization from 2000 to 2006. Multiple hypotheses have been proposed to explain the temporal variations in CH growth, and attribute the rise of atmospheric CH either to increases in emissions from fossil fuel activities, agriculture and natural wetlands, or to a decrease in the atmospheric chemical sink. Here, we use a comprehensive ensemble of CH source estimates and isotopic δC-CH source signature data to show that the resumption of CH growth is most likely due to increased anthropogenic emissions.

[2]Rotaxane as a switch for molecular electronic memory application: A molecular dynamics study.

As VLSI technology is shifting from microelectronics to nanoelectronics era, bi-stable [2]rotaxane emerges as a promising candidate for molecular electronics. A typical voltage-driven [2]rotaxane consists of a cyclobis-(paraquat-p-phenylene) macrocycle encircling a dumbbell shape molecular chain and moving between two stations on the chain: tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). As a molecular switch, the macrocycle can move reversibly between two stations along its axis with appropriate driving voltage, resulting in two stable molecular conformational states with distinct high and low resistance.

Expression of the transcription factor PU.1 induces the generation of microglia-like cells in human cortical organoids.

Microglia play a role in the emergence and preservation of a healthy brain microenvironment. Dysfunction of microglia has been associated with neurodevelopmental and neurodegenerative disorders. Investigating the function of human microglia in health and disease has been challenging due to the limited models of the human brain available.

Seasonal and annual variations of CO and CH at Shadnagar, a semi-urban site.

Carbon dioxide (CO) and methane (CH) are the most important greenhouse gases (GHGs) due to their significant role in anthropogenic global climate change. The spatio-temporal variations of their concentration are characterized by the terrestrial biosphere, seasonal weather patterns and anthropogenic emissions. Hence, to understand the variability in regional surface GHG fluxes, high precision GHGs measurements were initiated by the National Remote Sensing Center (NRSC) of India.

Strong Southern Ocean carbon uptake evident in airborne observations.

The Southern Ocean plays an important role in determining atmospheric carbon dioxide (CO), yet estimates of air-sea CO flux for the region diverge widely. In this study, we constrained Southern Ocean air-sea CO exchange by relating fluxes to horizontal and vertical CO gradients in atmospheric transport models and applying atmospheric observations of these gradients to estimate fluxes. Aircraft-based measurements of the vertical atmospheric CO gradient provide robust flux constraints.

Regional trends and drivers of the global methane budget.

The ongoing development of the Global Carbon Project (GCP) global methane (CH ) budget shows a continuation of increasing CH emissions and CH accumulation in the atmosphere during 2000-2017. Here, we decompose the global budget into 19 regions (18 land and 1 oceanic) and five key source sectors to spatially attribute the observed global trends. A comparison of top-down (TD) (atmospheric and transport model-based) and bottom-up (BU) (inventory- and process model-based) CH emission estimates demonstrates robust temporal trends with CH emissions increasing in 16 of the 19 regions.

Nitrogen oxides concentration and emission change detection during COVID-19 restrictions in North India.

COVID-19 related restrictions lowered particulate matter and trace gas concentrations across cities around the world, providing a natural opportunity to study effects of anthropogenic activities on emissions of air pollutants. In this paper, the impact of sudden suspension of human activities on air pollution was analyzed by studying the change in satellite retrieved NO concentrations and top-down NOx emission over the urban and rural areas around Delhi. NO was chosen for being the most indicative of emission intensity due to its short lifetime of the order of a few hours in the planetary boundary layer.

Gridded fossil CO emissions and related O combustion consistent with national inventories 1959-2018.

Quantification of CO fluxes at the Earth's surface is required to evaluate the causes and drivers of observed increases in atmospheric CO concentrations. Atmospheric inversion models disaggregate observed variations in atmospheric CO concentration to variability in CO emissions and sinks. They require prior constraints fossil CO emissions.

Detection of fossil-fuel CO plummet in China due to COVID-19 by observation at Hateruma.

The COVID-19 pandemic caused drastic reductions in carbon dioxide (CO) emissions, but due to its large atmospheric reservoir and long lifetime, no detectable signal has been observed in the atmospheric CO growth rate. Using the variabilities in CO (ΔCO) and methane (ΔCH) observed at Hateruma Island, Japan during 1997-2020, we show a traceable CO emission reduction in China during February-March 2020. The monitoring station at Hateruma Island observes the outflow of Chinese emissions during winter and spring.