ALBERT

Description: Extreme weather events threaten food security, yet global assessments of impacts caused by crop waterlogging are rare. Here we first develop a paradigm that distils common stress patterns across environments, genotypes and climate horizons. Second, we embed improved process-based understanding into a farming systems model to discern changes in global crop waterlogging under future climates. Third, we develop avenues for adapting cropping systems to waterlogging contextualised by environment. We find that yield penalties caused by waterlogging increase from 3–11% historically to 10–20% by 2080, with penalties reflecting a trade-off between the duration of waterlogging and the timing of waterlogging relative to crop stage. We document greater potential for waterlogging-tolerant genotypes in environments with longer temperate growing seasons (e.g., UK, France, Russia, China), compared with environments with higher annualised ratios of evapotranspiration to precipitation (e.g., Australia). Under future climates, altering sowing time and adoption of waterlogging-tolerant genotypes reduces yield penalties by 18%, while earlier sowing of winter genotypes alleviates waterlogging by 8%. We highlight the serendipitous outcome wherein waterlogging stress patterns under present conditions are likely to be similar to those in the future, suggesting that adaptations for future climates could be designed using stress patterns realised today.

Description: Air pollutants can be transported to the pristine regions such as the Tibetan Plateau, by monsoon and stratospheric intrusion. The Tibetan Plateau region has limited local anthropogenic emissions, while this region is influenced strongly by transport of heavy emissions mainly from South Asia. We conducted a comprehensive study on various air pollutants (PM2.5, total gaseous mercury, and surface ozone) at Nam Co Station in the inland Tibetan Plateau. Monthly mean PM2.5 concentration at Nam Co peaked in April before monsoon season, and decreased during the whole monsoon season (June–September). Monthly mean total gaseous mercury concentrations at Nam Co peaked in July and were in high levels during monsoon season. The Indian summer monsoon acted as a facilitator for transporting gaseous pollutants (total gaseous mercury) but a suppressor for particulate pollutants (PM2.5) during the monsoon season. Different from both PM2.5 and total gaseous mercury variabilities, surface ozone concentrations at Nam Co are primarily attributed to stratospheric intrusion of ozone and peaked in May. The effects of the Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau are complex and require further studies.

Description: The location of Central Asia, almost at the center of the global dust belt region, makes it susceptible for dust events. The studies on atmospheric impact of dust over the region are very limited despite the large area occupied by the region and its proximity to the mountain regions (Tianshan, Hindu Kush-Karakoram-Himalayas, and Tibetan Plateau). In this study, we analyse and explain the modification in aerosols’ physical, optical and radiative properties during various levels of aerosol loading observed over Central Asia utilizing the data collected during 2010–2018 at the AERONET station in Dushanbe, Tajikistan. Aerosol episodes were classified as strong anthropogenic, strong dust and extreme dust. The mean aerosol optical depth (AOD) during these three types of events was observed a factor of ~3, 3.5 and 6.6, respectively, higher than the mean AOD for the period 2010–2018. The corresponding mean fine-mode fraction was 0.94, 0.20 and 0.16, respectively, clearly indicating the dominance of fine-mode anthropogenic aerosol during the first type of events, whereas coarse-mode dust aerosol dominated during the other two types of events. This was corroborated by the relationships among various aerosol parameters (AOD vs. AE, and EAE vs. AAE, SSA and RRI). The mean aerosol radiative forcing (ARF) at the top of the atmosphere (ARFTOA), the bottom of the atmosphere (ARFBOA), and in the atmosphere (ARFATM) were −35 ± 7, −73 ± 16, and 38 ± 17 Wm−2 during strong anthropogenic events, −48 ± 12, −85 ± 24, and 37 ± 15 Wm−2 during strong dust event, and −68 ± 19, −117 ± 38, and 49 ± 21 Wm−2 during extreme dust events. Increase in aerosol loading enhanced the aerosol-induced atmospheric heating rate to 0.5–1.6 K day−1 (strong anthropogenic events), 0.4–1.9 K day−1 (strong dust events) and 0.8–2.7 K day−1 (extreme dust events). The source regions of air masses to Dushanbe during the onset of such events are also identified. Our study contributes to the understanding of dust and anthropogenic aerosols, in particular the extreme events and their disproportionally high radiative impacts over Central Asia.

Description: The seasonal aerosol radiative forcing efficiency (ARFE) in the atmosphere was found high (〉100 Wm-2) and consistent throughout the year over Dusanbe, the capital city of Tajikistan in central Asia. Consequently, this resulted in similar seasonally coherent high atmospheric solar heating rate (HR) of 1.5 K day-1 during summer-autumnwinter, and ca. 0.9 K day-1 during spring season. High ARFE and HR values indicate that atmospheric aerosols could exert significant implications to regional air quality, climate and cryosphere over the central Asian region and downwind Tianshan and Himalaya-Tibetan Plateau mountain regions with sensitive ecosystems.

Description: To understand the characteristics of particulate matter (PM) and other air pollutants in Xinjiang, a region with one of the largest sand-shifting deserts in the world and significant natural dust emissions, the concentrations of six air pollutants monitored in 16 cities were analyzed for the period January 2013–June 2019. The annual mean PM2.5, PM10, SO2, NO2, CO, and O3 concentrations ranged from 51.44 to 59.54 μg m−3, 128.43–155.28 μg m−3, 10.99–17.99 μg m−3, 26.27–31.71 μg m−3, 1.04–1.32 mg m−3, and 55.27–65.26 μg m−3, respectively. The highest PM concentrations were recorded in cities surrounding the Taklimakan Desert during the spring season and caused by higher amounts of wind-blown dust from the desert. Coarse PM (PM10-2.5) was predominant, particularly during the spring and summer seasons. The highest PM2.5/PM10 ratio was recorded in most cities during the winter months, indicating the influence of anthropogenic emissions in winters. The annual mean PM2.5 (PM10) concentrations in the study area exceeded the annual mean guidelines recommended by the World Health Organization (WHO) by a factor of ca. ∼5–6 (∼7–8). Very high ambient PM concentrations were recorded during March 19–22, 2019, that gradually influenced the air quality across four different cities, with daily mean PM2.5 (PM10) concentrations ∼8–54 (∼26–115) times higher than the WHO guidelines for daily mean concentrations, and the daily mean coarse PM concentration reaching 4.4 mg m−3. Such high PM2.5 and PM10 concentrations pose a significant risk to public health. These findings call for the formulation of various policies and action plans, including controlling the land degradation and desertification and reducing the concentrations of PM and other air pollutants in the region.

Description: Indoor air pollution (IAP) is one of the leading risk factors for various adverse health outcomes including premature deaths globally. Even though research related to IAP has been carried out, bibliometric studies with particular emphasis on this topic have been lacking. Here, we investigated IAP research from 1990 to 2019 retrieved from the Web of Science database through a comprehensive and systematic scientometric analysis using the CiteSpace 5.7.R2, a powerful tool for visualizing structural, temporal patterns and trends of a scientific field. There was an exponential increase in publications, however, with a stark difference between developed and developing countries. The journals publishing IAP related research had multiple disciplines; ‘Indoor Air’ journal that focuses solely on IAP issues ranked fifth among top-cited journals. The terms like ‘global burden’, ‘comparative risk assessment,’ ‘household air pollution (HAP)', ‘ventilation’, ‘respiratory health’, ‘emission factor’, ‘impact,’ ‘energy’, ‘household’, ‘India’ were the current topical subject where author Kirk R. Smith was identified with a significant contribution. Research related to rural, fossil-fuel toxicity, IAP, and exposure-assessment had the highest citation burst signifying the particular attention of scientific communities to these subjects. Overall, this study examined the evolution of IAP research, identified the gaps and provided future research directions.

Description: Long-term (2004–2015) satellite data over three adjacent yet contrasting regions: Indo-Gangetic Plain, Himalayas and Tibetan Plateau (TP) were used to study the spatiotemporal distribution of total ozone column (TOC) and its precursor gases (such as nitrogen dioxide (NO2), methane (CH4) and carbon monoxide (CO)). The ozone precursor emission data and forest fire points were used to explore the findings. Trace gases showed increasing trend probably due to increasing emission from South Asia as supported by the Emission Database for Global Atmospheric Research emission data. Strong seasonal variation in trace gases was observed with the highest value during the pre-monsoon season, over three regions, possibly due to the biomass burning, pollution build-up and also long-range transport of pollution. TOC exhibited the similar seasonal variation as shown by the earlier ground-based studies over the region. The total column of precursor gases (except methane) exhibited strong seasonality with the highest column during the pre-monsoon season. Patterns in the variations of TOC and related precursors over the Himalayas were similar with that of the TP. Seasonal climatological trends also exhibited increasing pattern except for CO. This work provides an overview on the long-term TOC and its precursor gases which are necessary to understand the regional climate variability especially over the Himalayas and Tibetan Plateau region.

Description: Air pollution is a grand challenge of our time due to its multitude of adverse impacts on environment and society, with the scale of impacts more severe in developing countries, including China. Thus, China has initiated and implemented strict air pollution control measures over last several years to reduce impacts of air pollution. Monitoring data from Jan 2015 to Dec 2019 on six criteria air pollutants (SO2, NO2, CO, O3, PM2.5, and PM10) at eight sites in southwestern China were investigated to understand the situation and analyze the impacts of transboundary air pollutants in this region. In terms of seasonal variation, the maximum concentrations of air pollutants at these sites were observed in winter or spring season depending on individual site. For diurnal variation, surface ozone peaked in the afternoon while the other pollutants had a bimodal pattern with peaks in the morning and late afternoon. There was limited transport of domestic emissions of air pollutants in China to these sites. Local emissions enhanced the concentrations of air pollutants during some pollution events. Mostly, the transboundary transport of air pollution from South Asia and Southeast Asia was associated with high concentrations of most air pollutants observed in southwestern China. Since air pollutants can be transported to southwestern China over long distances from the source regions, it is necessary to conduct more research to properly attribute and quantify transboundary transport of air pollutants, which will provide more solid scientific guidance for air pollution management in southwestern China.

Description: Black carbon (BC) aerosol impacts the air quality, public health, agricultural productivity, weather, monsoon, cryosphere, and climate system from the local to the global scale. However, its distribution over vast Central Asia is poorly known, because it is one of the poorly sampled regions of the world. BC in the soil can be resuspended into the atmosphere and transported to downwind regions with sensitive ecosystems and vulnerable populations, such as from Central Asian countries to the cryospheric regions in the Tianshan Mountain and the Tibetan Plateau, which could accelerate the melting of the snowfields and glaciers. We report the distribution of BC and total organic carbon (TOC) in surface soil with samples collected at multiple sites, for the first time, over three countries in Central Asia (Uzbekistan, Tajikistan, and Kyrgyzstan). The mean BC (TOC) concentrations over three countries were 0.06 ± 0.06 (11.86 ± 4.84) mg g−1, 0.15 ± 0.21 (20.35 ± 10.96) mg g−1, and 0.32 ± 0.29 (26.45 ± 20.38) mg g−1, respectively. They were found to be originated from the same or similar sources, at least over Tajikistan and Kyrgyzstan, as indicated by their high and significant correlation (R2 〉 0.6, p 〈 0.001). The char/soot ratio indicated the diesel and gasoline combustion as dominant BC sources over this region. To gain further insights into the soil BC and its implications to air quality, climate, and cryosphere, future studies should include a wider area over Central Asia with different land-use types and other soil parameters combined with atmospheric simulations for this important yet relatively less studied region of the world.

Description: Thaw slumps can lead to considerable carbon loss in permafrost regions, while the loss of components from two major origins, i.e., microbial and plant-derived carbon, during this process remains poorly understood. Here, we provide direct evidence that microbial necromass carbon is a major component of lost carbon in a retrogressive permafrost thaw slump by analyzing soil organic carbon (SOC), biomarkers (amino sugars and lignin phenols), and soil environmental variables in a typical permafrost thaw slump in the Tibetan Plateau. The retrogressive thaw slump led to a ∼61% decrease in SOC and a ∼25% SOC stock loss. As evident in the levels of amino sugars (average of 55.92 ± 18.79 mg g–1 of organic carbon, OC) and lignin phenols (average of 15.00 ± 8.05 mg g–1 OC), microbial-derived carbon (microbial necromass carbon) was the major component of the SOC loss, accounting for ∼54% of the SOC loss in the permafrost thaw slump. The variation of amino sugars was mainly related to the changes in soil moisture, pH, and plant input, while changes in lignin phenols were mainly related to the changes in soil moisture and soil bulk density.