Methane retrieval from Atmospheric Infrared Sounder using EOF-based regression algorithm and its validation

The role of satellite remote sensing in mitigating and adapting to global climate change

Climate change has critical adverse impacts on human society and poses severe challenges to global sustainable development. Information on essential climate variables (ECVs) that reflects the substantial changes that have occurred on Earth is critical for assessing the influence of climate change. Satellite remote sensing (SRS) technology has led to a new era of observations and provides multiscale information on ECVs that is independent of in situ measurements and model simulations. This enhances our understanding of climate change from space and supports policy-making in combating climate change. However, it remains challenging to remotely retrieve ECVs due to the complexity of the climate system. We provide an update on the studies on the role of SRS in climate change research, specifically in monitoring and quantifying ECVs in the atmosphere (greenhouse gases, clouds and aerosols), ocean (sea surface temperature, sea ice melt and sea level rise, ocean currents and mesoscale eddies, phytoplankton and ocean productivity), and terrestrial ecosystems (land use and land cover change and carbon flux, water resource and hydrological hazards, solar-induced chlorophyll fluorescence and terrestrial gross primary production). The benefits and challenges of applying SRS in climate change studies are also examined and discussed. This work will help us apply SRS and recommend future SRS studies to mitigate and adapt to global climate change.

Diurnal and seasonal variations in surface methane at a tropical coastal station: Role of mesoscale meteorology

In view of the large uncertainties in the methane (CH₄) emission estimates and the large spatial gaps in its measurements, studies on near-surface CH₄ on regional basis become highly relevant. This paper presents the first time observational results of a study on the impacts of mesoscale meteorology on the temporal variations of near-surface CH₄ at a tropical coastal station, in India. It is based on the in-situ measurements conducted during January 2014 to August 2016, using an on-line CH₄ analyzer working on the principle of gas chromatography. The diurnal variation shows a daytime low (1898-1925ppbv) and nighttime high (1936-2022ppbv) extending till early morning hours. These changes are closely associated with the mesoscale circulations, namely Sea Breeze (SB) and Land Breeze (LB), as obtained through the meteorological observations, WRF simulations of the circulations and the diurnal variation of boundary layer height as observed by the Microwave Radiometer Profiler. The diurnal enhancement always coincides with the onset of LB. Several cases of different onset timings of LB were examined and results presented. The CH₄ mixing ratio also exhibits significant seasonal patterns being maximum in winter and minimum in pre-monsoon/monsoon with significant inter-annual variations, which is also reflected in diurnal patterns, and are associated with changing synoptic meteorology. This paper also presents an analysis of in-situ measured near-surface CH₄, column averaged and upper tropospheric CH₄ retrieved by Atmospheric Infrared Sounder (AIRS) onboard Earth Observing System (EOS)/Aqua which gives insight into the vertical distribution of the CH₄ over the location. An attempt is also made to estimate the instantaneous radiative forcing for the measured CH₄ mixing ratio.

Spatiotemporal Monitoring of CO₂ and CH₄ over Pakistan Using Atmospheric Infrared Sounder (AIRS)

Carbon dioxide (CO2), Methane (CH4) are two most potent greenhouse gases and are major source of climate change. Human activities particularly fossil fuels burning have caused considerable increase in atmospheric concentrations of greenhouse gases. CO2 contributes 60% of anthropogenic greenhouse effect whereas CH4 contributes 15%. Ice core records also show that the concentrations of Carbon dioxide and methane have increased substantially. The emission of these gases alters the Earth’s energy budget and are drivers of climate change. In the present study, atmospheric concentration of CO2 and CH4 over Pakistan is measured using Atmospheric Infrared Sounder (AIRS). Time series and time averaged maps are prepared to measure the concentrations of CO2 and CH4. The results show considerable increase in concentration of Carbon dioxide and methane. The substantial increase in these concentrations can affect human health, earth radiative balance and can damage crops.

Spatiotemporal Monitoring of CO₂ and CH₄ over Pakistan Using Atmospheric Infrared Sounder (AIRS)

Carbon dioxide (CO2), Methane (CH4) are two most potent greenhouse gases and are major source of climate change. Human activities particularly fossil fuels burning have caused considerable increase in atmospheric concentrations of greenhouse gases. CO2contributes 60% of anthropogenic greenhouse effect whereas CH4contributes 15%. Ice core records also show that the concentrations of Carbon dioxide and methane have increased substantially. The emission of these gases alters the Earth’s energy budget and are drivers of climate change. In the present study, atmospheric concentration of CO2and CH4over Pakistan is measured using Atmospheric Infrared Sounder (AIRS). Time series and time averaged maps are prepared to measure the concentrations of CO2and CH4. The results show considerable increase in concentration of Carbon dioxide and methane. The substantial increase in these concentrations can affect human health, earth radiative balance and can damage crops.