Vinayak Bhanage

Environmental disruption is an inevitable issue faced by top-tier cities worldwide. In the present study, ecological degradation induced by changes in land use and land cover (LULC) within the Kolkata municipal corporation (KMC) was analyzed over the last 30 years (1994–2024). The comprehensive ecological evaluation index (CEEI) and Carbon Storage and ecosystem service values (ESV) were used as indicators of ecological conditions in terms of quality, quantity, and economy. Based on a comparative analysis of Google Earth Engine classifiers, the Random Forest algorithm was found to be the most suitable classifier for a humid-tropical city such as KMC. The LULC transition analysis showed that the built-up area increased by almost 50% from 1994 to 2024, while vegetation, water bodies, and Bare land decreased by 38%, 27%, and 47%, respectively. As a result, indicators of ecological conditions have declined. The minimum CEEI decreased from 0.32 to 0.21 between 1994 and 2024, indicating massive qualitative degradation. The city lost 0.4 million Mg of stored carbon and 3.7 million $USD/year in ESV during the period, at a rate of −0.08 million $USD/year. The results of the cluster analysis show that the Low Cluster, which comprises 75%–90% of compact built-up areas, is steadily spreading from the north towards the south of the city. The Moderate Cluster represents the transitional zone that was vegetation-dominant in the earlier years but transformed into built-up areas in the later years. The Good Cluster, which is a vegetation- and waterbody-dominant cluster that spread across the vegetated lands of southern Kolkata in 1994, shrank towards the Eastern Kolkata Wetlands region in later years. The findings of the study reveal that the Moderate and Good clusters, although already in a declining trend, still have scope for improvement with proper planning to counter the push effects of the low cluster.

Cities create their own local climate, and numerical weather models can reproduce it if given an accurate picture of the urban surface. The local climate zone (LCZ) framework classifies neighborhoods by building height, density, and materials and provides this information to fine-scale weather models. This approach has mostly been evaluated in warm seasons, leaving open how it performs in the cold, air-stagnant winters of high-latitude cities like Ulaanbaatar, Mongolia. We ran nine model versions over one cold week (22–29 February 2024) across three nested domains (12.5, 2.5, and 0.5 km) with LCZ data resolved to 100 m. Run 8 achieved the highest aggregate validation skill, whereas Run 9 was retained as the configuration most suitable for the LCZ-based analysis rather than as the best model overall. Run 9 reproduced near-surface temperature at the urban Bayanzurkh station (R = 0.89) and gave the smallest wind-speed error (1.5 m s⁻¹), while uniquely resolving the inter-class morphological contrasts required here. The dense urban core proved warmer than the non-urban area by 4.1 °C on average and up to 9.3 °C at night in the compact high-rise zone. Yet this warming barely relieves cold stress: the Universal Thermal Climate Index (UTCI) averaged −15.5 °C across the LCZ classes, within the strong-cold-stress range, with only the compact high-rise zone reaching a milder category. In the low-rise “ger districts”, wind speed rather than air temperature governs perceived cold, and compact high-rise form offers the strongest wind shelter. These findings provide a baseline for future scenario testing of winter thermal exposure in Ulaanbaatar.

This study examines the quality of urban life (QoUL) in Ulaanbaatar by analyzing variations in overall life satisfaction across urban development types and identifying the sociodemographic, housing, mobility, and domain-specific factors associated with these differences. An integrated methodological framework combining questionnaire survey data and spatial information was utilized to analyze 529 valid responses collected from five urban development contexts: new development, redevelopment, land readjustment, urban sprawl, and other areas. The analysis employed descriptive statistics, comparative group analysis, and ordinal logistic regression models. Overall life satisfaction differed significantly across development types. The land readjustment areas reported the highest mean value of life satisfaction (3.64), followed by new development (3.53), urban sprawl (3.32), redevelopment (3.13), and other areas (2.97). In the pooled model, higher educational attainment was negatively associated with overall life satisfaction (OR = 0.30, p < 0.05), possibly reflecting higher expectations among better educated residents. In contrast, longer residential duration, particularly beyond 10 years, was positively associated with overall life satisfaction, indicating the importance of residential stability and place attachment. Household composition also emerged as relevant, with family-related responsibilities and child-supportive living conditions shaping how urban environments are experienced. Across development types, accessibility, environmental quality, and dwelling satisfaction were the most consistent predictors. These findings indicate that improving QoUL in Ulaanbaatar requires development-type-specific, people-centered policies that integrate housing, transport, environmental improvement, neighborhood services, and family-supportive interventions to support more sustainable and equitable urban development.

The relocation of Indonesia’s capital to Nusantara in East Kalimantan has raised concerns about microclimatic impacts resulting from proposed land use and land cover (LULC) changes. This study explored strategies to mitigate these impacts by using dynamical downscaling with the Weather Research and Forecasting model integrated with the urban canopy model (WRF-UCM). Numerical experiments at a 1 km spatial resolution were used to evaluate the impacts of green and mitigation strategies on the proposed master plan. In this process, five scenarios were analyzed, incorporating varying proportions of blue–green spaces and modifications to building walls and roof albedos. Among them, scenario 5, with 65% blue–green spaces, exhibited the highest cooling potential, reducing average urban surface temperatures by approximately 2 °C. In contrast, scenario 4, which allocated equal shares of built-up areas and mixed forests (50% each), achieved a more modest reduction of approximately 1 °C. The adoption of nature-based solutions and sustainable urban planning in Nusantara underscores the feasibility of climate-resilient urban development. This framework could inspire other cities worldwide, showcasing how urban growth can align with environmental sustainability.

The Model for Prediction Across Scales–Atmosphere (MPAS-A) has been widely used for larger scale simulations, but its performance in mesoscale, particularly in tropical regions, is less evaluated. This study aimed to assess MPAS-A in simulating extreme surface air temperature in Jakarta during the hot spells of October 2023 with eight different simulation setups. Several validation metrics were applied to near-surface meteorological variables, land surface temperature (LST), and vertical atmospheric profile. From the eight simulations, MPAS-A captured diurnal patterns of the near-surface variables well, except for wind direction. The model also performed well in LST simulations. Moreover, the biases in the vertical profiles varied with height and were sensitive to the initial/boundary conditions used. Simulations with modified terrestrial datasets showed higher LST and air temperatures over the sprawling urban areas. MPAS-A successfully simulated the extreme event, showing higher air temperatures in southern Jakarta (over 36 °C) compared to the northern part. Negative temperature advection by sea breeze helped lower air temperature in the northern area. This study highlights the role of sea breezes as natural cooling mechanisms in coastal cities. Additionally, MPAS-A is feasible for several applications for urban climate studies and climate projection, although further development is needed.