Quantifying Spatio Temporal Changes in Coastal Buit-up area of South Goa based on Landsat Imageries using Google Earth Engine

Urban flooding has become a significant concern across many towns and cities in the Asia Pacific. Vulnerabilityand its components must be understood in order to minimize flood risks. Rapid urban growth occurs in developing countries,resulting from unplanned settlements growing along the rivers, and coastlines are at greater risk. On average, a total of 40%of the world’s population lives in narrow coastal belts that take up 7% of the total world land area. Coastal areas areurbanizing at an unprecedented rate that is posing a common threat to humans and ecosystems. Low-lying coastal areas areespecially susceptible to climate change related coastal hazards such as; sea level rise, storm surge, coastal flooding, landsubsidence etc.This study has been carriedoutacross four talukas of South Goa district, India's smallest state, locatedalong the Arabian sea. The low-lying coastal belt of South Goa district is dotted with world famous sandy beaches ofPalolem, Agonda, Colva etc. which attract millions of tourists every year. The present study has assessed the spatio-temporalgrowth of built-up land in low-lying coastal areas (Marmugao, Salcette, Quepem and Canacona) of South goa district.GoogleEarthEngineplatformwasusedtoestimateNormalizedDifferenceBuildIndex(NDBI)basedonLandsatETM+/OLI imageries for 2009, 2015 and 2020 to determine and map spatio-temporal changes in the total built-up area. Theresult revealed that there had been a rapid built-up area increment in South goa coastal belt by 24.94 Sq. Km between 2009(88.46 Sq. Km) and 2015 (113.40 Sq. Km) and by 15.14 Sq. Km between 2015 (113.40 Sq. Km) and 2020 (128.54 Sq. Km).The main driving force behind this phenomenon is the extensive land use changes for haphazard tourism development (inSalcetteandCanacona)andimmigration(inMarmugao).However,theconversionoftraditionalpaddyfieldsandmodification of natural drainage systemtoincrease built-up areas cansignificantly increase the physical andsocialvulnerability in low lying areas of Salcette and Canacona against the coastal hazards. This study may help urban planners/authoritiestolettheregiondevelopin sustainablemanne

Did Covid-19 lockdown positively affect the urban environment and UN- Sustainable Development Goals?

Nigam, R., Tripathi, G., Priya, T., Luis, A. J., Vaz, E., Kumar, S., Shakya, A., Damásio, B., Kotha, M., & Yu, B. (Ed.) (2022). Did Covid-19 lockdown positively affect the urban environment and UN- Sustainable Development Goals? PLoS ONE, 17(9), 1-21. [e0274621]. https://doi.org/10.1371/journal.pone.0274621This work quantifies the impact of pre-, during- and post-lockdown periods of 2020 and 2019 imposed due to COVID-19, with regards to a set of satellite-based environmental parameters (greenness using Normalized Difference Vegetation and water indices, land surface temperature, night-time light, and energy consumption) in five alpha cities (Kuala Lumpur, Mexico, greater Mumbai, Sao Paulo, Toronto). We have inferenced our results with an extensive questionnaire-based survey of expert opinions about the environment-related UN Sustainable Development Goals (SDGs). Results showed considerable variation due to the lockdown on environment-related SDGs. The growth in the urban environmental variables during lockdown phase 2020 relative to a similar period in 2019 varied from 13.92% for Toronto to 13.76% for greater Mumbai to 21.55% for Kuala Lumpur; it dropped to −10.56% for Mexico and −1.23% for Sao Paulo city. The total lockdown was more effective in revitalizing the urban environment than partial lockdown. Our results also indicated that Greater Mumbai and Toronto, which were under a total lockdown, had observed positive influence on cumulative urban environment. While in other cities (Mexico City, Sao Paulo) where partial lockdown was implemented, cumulative lockdown effects were found to be in deficit for a similar period in 2019, mainly due to partial restrictions on transportation and shopping activities. The only exception was Kuala Lumpur which observed surplus growth while having partial lockdown because the restrictions were only partial during the festival of Ramadan. Cumulatively, COVID-19 lockdown has contributed significantly towards actions to reduce degradation of natural habitat (fulfilling SDG-15, target 15.5), increment in available water content in Sao Paulo urban area(SDG-6, target 6.6), reduction in NTL resulting in reducied per capita energy consumption (SDG–13, target 13.3).publishersversionpublishe

Giant magnetoresistance in the cluster glass regime of Co-Ga alloys

A detailed study of low temperature electrical transport properties of CoxGa100−x (x = 54, 55.5, 57) alloy has been carried out. The origin of the resistivity anomalies and correlation between magnetic and electrical transport properties are identified through an elaborate analysis. The weak localization and enhanced electron-electron interaction effects partially support the electrical transport properties of the system. Further, the observed magnetoresistance can be well represented by localized model along with quantum corrections. The low temperature magnetoresistance value near critical composition is comparable to that reported in giant magnetoresistance materials

Summary of variations in urban environmental parameters and the effect of lockdown.

Summary of variations in urban environmental parameters and the effect of lockdown.</p

Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Toronto city.

Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Toronto city.</p

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Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Sao Paulo city.

Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Sao Paulo city.</p

Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Mumbai city.

Spatio-temporal changes in a) NDVI, b) NDWI, c) LST and d) NTL based on the thematic maps of the Mumbai city.</p

Lockdown and its link to environmental parameters and UN-SDG targets.

Lockdown and its link to environmental parameters and UN-SDG targets.</p

Impact of COVID-19 lockdown restriction on Alpha cities relative to similar period in 2019.

Impact of COVID-19 lockdown restriction on Alpha cities relative to similar period in 2019.</p