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Air pollution potential is a measure of the inability of the atmosphere to disperse pollutants away from the source. It depends on Planetary Boundary Layer Height (PBLH) and wind speed. Global air pollution potential Index (APPI) maps have been generated for the first time using 40 years (1980–2019) of PBLH and wind speed data available from ECMWF Reanalysis v5 (ERA5) data. These are useful for identifying ventilation corridors and for sustainable development. The seasonal climatology of APPI is also analyzed. Long-term trends in Ventilation coefficient (VC), PBLH, Wind speed, PM2.5, and Aerosol Optical Thickness (AOT) were analyzed globally and in over 30 cities to understand their future impact on climate change scenarios. High APPI is observed in the South Asian regions, giving rise to PM2.5 and AOT hot spots, and are naturally disadvantageous. Long-term trends in VC and associated trends in PBLH and Wind speed suggest that the PBLH is decreasing at the rate of 1–3 m per year over south Asia, and wind speed is decreasing at the rate of 0.01–0.02 m·s− 1per year, resulting in the decrease of VC of about 1–25 m2·s− 1per year. If this trend continues, South Asia will have more air pollution potential, causing severe stagnation of air pollutants in the coming years and putting health risks to 1.8 billion people. The surface PM2.5 and AOT are increasing at 0.5–1.5 µg·m− 3 per year and 0.005–0.01 per year for South Asia cities. Sustainable development goals and climate policies/negotiations should consider global air pollution potential as an essential variable in planning and mitigation. [ABSTRACT FROM AUTHOR]

The Great Lakes Depression region basin is among the most sensitive regions to vegetation change due to climate change. This study estimated spatial-temporal changes and relationships in hydro-climate and vegetation dynamics in the basin. Studying the spatial-temporal variation between vegetation dynamics and hydro-climate in this basin is essential for assessing climate change and sustainability. This research involved an examination of the mean yearly air temperature, overall annual rainfall, fluctuations in river discharge, vegetation cover, and alterations in vegetation types within the selected basin stations. This was accomplished through the utilization of hydro-meteorological analysis, satellite assessment, land cover determination, and statistical analysis. Over the course of the study, it was observed that the average annual air temperature increased at all stations (with a positive change of Z = +1.16). The amount of precipitation decreased (Z = −0.79), especially from 2000 to 2014, and its statistical significance decreased. During the study period, average river discharge significantly decreased (Z = −3.51). Due to these combined factors, the lake's water level also decreased (Z = −2.03). Vegetation cover change varied in high mountains, near river and lake water surfaces, and in arid regions. Changes in air temperature and precipitation in the current year determine vegetation cover. Because of the large amount of precipitation in the summer months from 2000 to 2010 and 2020, the growth of vegetation cover during that period was relatively good. This study was conducted in arid and semi-arid regions of Central Asia and demonstrates the impact of climate change on changes in vegetation cover. [ABSTRACT FROM AUTHOR]

Many studies have been conducted on air pollution in Ulaanbaatar city. However, most have focused on the sources of pollutants and their characteristics and distribution. Although the location of the city subjects it to unavoidable natural conditions where air pollution accumulates during the cold season, nature-based solutions have not yet been considered in the projects implemented to mitigate air pollution levels. Therefore, this study aims to determine the combined influence of geography and atmospheric factors on cold season air pollution. The spatiotemporal variations in the variables were investigated using meteorological observation data from 1991 to 2020 in the different land-use areas. Then, atmospheric stagnation conditions and air pollution potential parameters were estimated from daily radiosonde data. Subsequently, the temporal variations in air pollutants were studied and correlated with estimates of the above parameters. In the Ulaanbaatar depression, the stable cold air lake (colder than −13.5 °C), windless (34–66% of all observations), and poor turbulent mixing conditions were formed under the near-surface temperature inversion layer in the cold season. Moreover, due to the mountain topography, the winds toward the city center from all sides cause polluted air to accumulate in the city center for long periods. Air pollution potential was categorized as very high and high (<4000 m2·s−1), in the city in winter, indicating the worst air quality. Thus, further urban planning policy should consider these nature factors. [ABSTRACT FROM AUTHOR]

This study used the Innovative trend analysis method, Mann-Kendall, and Sen's slope estimator test to investigate the mean annual precipitation, annual mean air temperature, and river discharge at selected stations of the sub-basin. The results showed that the trend of annual precipitation trend was significantly increased in Nizhneangarsk station (ф = 0.88 and Z = –0.64) and Bolshoe Goloustnoe (ф = 0.24 and Z = 1.14*) whereas, the other stations showed a decreasing trend. The most decreasing trend was observed in the Ust Barguzin station (ф = –0.68, Z = –2.38**, and β = –0.95). The average air temperature has increased by 1.7°C from 1970 to 2019. All stations showed an increasing trend of annual air temperature during the study period. The most increasing condition was observed in the Ulan Ude station (ф = 9.20***, Z = 7.78***, and β = 0.04). The river discharge showed an increasing trend in Utulik River, Upper Angara River, and Barguzin rivers. The most decreasing is in the Selenga river gauge station (ф = –2.25**, Z = –2.16**, and β = –2.96**). The warming rates in the Selenga river sub-basin of the study area were higher than those in the other four sub-basins and the global climate change more affects the semi-arid region. [ABSTRACT FROM AUTHOR]

Air pollution potential indicates the ability of the atmosphere to disperse the pollutants depends on mixing height and wind speed. This parameter is essential for air dispersion modeling, mitigating air pollution, i.e., reducing harmful effects on human health, and potential site selection for establishing new industries. Five-year (2015–2019) mean monthly, seasonal, and annual maps of ventilation coefficient (VC) and air pollution potential index (APPI) were prepared for the first time for India using the inputs from daily data of planetary boundary layer height (PBLH) derived using CrIS onboard SOUMI-NPP satellite and wind speed from ERA-5. Climatology of VC and APPI over 14 cities in India was also analyzed. Below medium to very low pollution potential (VC: 6000 to > 10,000 m2/s) has been observed at the east coast of Andhra Pradesh and Tamilnadu (TN) during the winter and most of western India and New Delhi during the summer monsoon. During pre-monsoon, western Gujarat, southwest of Rajasthan, and parts of Indo-Gangetic Plains show below medium to low pollution potential. Below medium pollution potential is observed at the east coast of TN during the post-monsoon season. Annual averages of VC and APPI suggest east coastal TN and western Gujarat consistently are below medium to very low pollution potential zone, indicating their suitability for setting up new industries. Annual average VC shows the cities with increasing pollution potential as Mumbai, Chennai, Bangalore, Hyderabad, Patna, Jaisalmer, Jodhpur, Varanasi, Kolkata, Kanpur, Lucknow, New Delhi, Nagpur, and Rourkela. This information is helpful to the regulatory authorities to prioritize the air pollution mitigation measures in different cities. This study has the potential to be extended to prepare global maps of APPI to identify ventilation corridors (regions with very low pollution potential) that will reduce air pollution and its effects on human health, the environment, and the climate at large. [ABSTRACT FROM AUTHOR]

The Ugii Nuur Lake is not only one of the small hydrologically closed lakes located in the Orkhon River Basin in Central Mongolia but also the most vulnerable area for global climate change. Therefore, this study aims to investigate the impacts of recent global climate change on the water surface area. The data we analyzed were various measured hydro-meteorological variables of the lake basin and the lake surface area, which was estimated from Landsat series satellite data from 1986 to 2018. The methods we used were Mann-Kendall (MK), Innovative trend analysis method (ITAM), Sen's slope estimator test, correlation, and regression analysis. The variation of lake water surface area has a strong positive correlation with the change of the lake water level (r = 0.95). The Mann-Kendall trend analysis has indicated that under a significant decrease in total annual precipitation ( Z   = −0.902) and inflow river discharge ( Z   = −5.392) and a considerable increase in total annual evaporation (Z = 4.385) and annual average air temperature ( Z   = 4.595), the surface area of the Ugii Nuur Lake has decreased sharply (Z = −6.021). The total annual evaporation (r = −0.64) and inflow river discharge (r = 0.67) were the essential hydro-meteorological factors affecting the surface area of the Ugii Nuur Lake. The lake surface area decreased by 13.5% in 2018 compared with 1986. In the near future, it is vital to conduct scientific studies considering the volume of lake water, groundwater, and the anthropogenic impact. [ABSTRACT FROM AUTHOR]