ALBERT

Beschreibung: In recent times, a significant number of studies on the composition and sources of fine particulate matters and volatile organic compounds have been carried out over Delhi, either initiated by or in association with the researchers from the Indian Institute of Technology Kanpur (IIT Kanpur), in collaboration with researchers from within and outside India. All these studies utilized highly time-resolved, campaign-mode observations made with state-of-the-art instrumentation during the late winter months (mid-January to March) of 2018. Individually, each of these studies were rigorous in nature, containing explicit detailing about different types of ambient air pollutants in Delhi such as organic aerosols, inorganic elements, metals, carbonaceous aerosols, and volatile organic compounds. This study consolidates the extremely useful knowledge on source attribution of these air pollutants in the Delhi National Capital Region currently contained in these fragmented studies, which is vital to further enhancing our understanding of composition, characteristics, and sources of air pollutants over Delhi, as well as to designing appropriate mitigation measures tailored to local specifics.

Beschreibung: Particulate matter (PM) pollution is a major challenge in India. The Ministry of Environment, Forest and Climate Change, Government of India has launched the National Clean Air Programme for monitoring, assessment and control of air pollution. The action plan envisions reduction in air pollution on the basis of source apportionment studies in all the non-attainment cities. Source apportionment (SA) using receptor modelling is important for understanding the PM sources, pollution outflow and larger scale regional impacts. This review presents current status of offline and online measurement based SA studies focusing on PM10 and finer fractions of PM, where receptor modelling on chemical species has been used to apportion contributions from different sources. While a good database is available on chemical characterization of ambient aerosols, only 49 offline and 16 online SA studies could qualify this criterion. Out of all offline studies reviewed here, only 41% studies measured all chemical signatures. State of the SA studies over different geographical divisions [Indo-Gangetic plain (IGP), Delhi NCR, western, eastern and central India] over India reveal that more than 50% of the studies are focused on the Delhi National Capital Region (NCR) and IGP. The most studied size fractions are PM10 (34%) and PM2.5 (28%) followed by 11% studies on PM1 and only 5% on size segregated SA of aerosols. The meta-analysis of available data on percentage contribution of major sources viz. secondary sources, biomass burning, combustion, vehicular emissions, industrial sources from these locations present a composite picture of major sources of ambient aerosols in India. This work also presents detailed discussion on different steps of SA viz. sampling design, analytical techniques and receptor modelling. The evolution from offline filter-based techniques to real time SA techniques has been discussed and recommendations for robust SA studies have been proposed.

Beschreibung: Monitoring the water level of reservoirs, lakes, and other inland water bodies is essential for hydrology. The lake system is a complex interaction between the atmosphere, surface and groundwater, revealing climatic changes. Many techniques exist to estimate the mass change or water level, and satellite altimetry is one of those techniques to monitor the water level changes of lakes or reservoirs. In recent years, the accuracy of altimetry has improved to centimeter-level, which enables studies on surface water more precisely. The accuracy of altimetry depends on factors such as water body width, radar waveform and the altimeter used. For the same region, the accuracy of altimetry observations can differ depending upon the aforementioned factors. This study has compared altimetry data (Database for Hydrological Time Series of Inland Waters - DAHITI) with the in-situ observations for Gandhi Sagar reservoir. DAHITI database provides the hydrological time series of water bodies using multi-mission satellite altimetry. For this study, 7 years of data (2013-2020) have been taken, consisting of Jason 2/3 and Sentinel 3A, optical and microwave images. In comparison, it is observed that some altimetry observations show significant variation from the in-situ observations. For pre-monsoon and post-monsoon, the coefficient of determination (r squared) is 0.921 and 0.933, respectively, but relatively low (0.873) for monsoon. The role of the surface water area and radar waveform to account for these variations is explored.

Beschreibung: Groundwater resources are depleting due to phenomena such as significant climate change and overexploitation. Therefore, it is essential to estimate water production and identify potential groundwater zones. An integrated conceptual framework comprising GIS and the analytical hierarchy process (AHP) has been applied for the present study to identify groundwater potential areas in the Thalawa division of Sri Lanka. The criteria, including rainfall, soil types, slope, stream density, lineament density, geology, geomorphology, and land use, were taken into account as the most contributing factors when identifying the groundwater zones. Weights were allocated proportionally to the eight thematic layers according to their importance. Hierarchical ranking and final normalized weighting of these determinants were performed using the pairwise comparison matrix (PCM) available in AHP. Based on the results obtained, the groundwater potential zone (GWPZ) was classified into three regions: low potentiality (33.4%), moderate potentiality (55.8%), and high potentiality (10.6%). Finally, the zoning map was compared to find consistency with field data on groundwater discharge and depth taken from 18 wells in the division. The results revealed that the GIS-multi-criteria decision-making (MCDM) approach brings about noticeably better results, which can support groundwater resource planning and sustainable use in the research area.