Lidar-derived aerosol concentration and their relationship with horizontal winds over an urban location

Lidar-derived aerosol vertical profiles obtained at Pune, a low latitude tropical station, on about 535 days during a ten-year period (1987 – 96) along with simultaneous pilot-balloon wind (speed and direction) data of India Meteorological Department, Pune have been used in the study to investigate the influence of horizontal winds on the aerosol characteristics in the lower atmosphere. Aerosol column content in the atmospheric boundary layer (surface to 1100 m altitude above ground-level) as well as aerosol number density at the surface level (at 50 m) showed relatively higher values over the lidar site whenever the winds were blowing from the main urban and industrial regions of the city of Pune. This effect was found to be more pronounced during the winter season. Wind speeds also correlate well with increased aerosol loading, but only during selected high wind speed episodes. Thus the study shows that the short- and long-term increases in aerosol concentration/loading over the observation site are, to a large extent, influenced by horizontal winds in the surface layers and this in turn, can be attributed to the increasing human/urban activity around the lidar site over the years.

Discovery of a New Ozone Hole over the Tropics

This paper reveals a new ozone hole that exists in the lower stratosphere over the tropics (30°N-30°S) across the seasons since the 1980s, where an ozone hole is defined as an area of ozone loss larger than 25% compared with the undisturbed atmosphere. The depth of this all-season tropical ozone hole is comparable to that of the well-known springtime ozone hole over Antarctica, while its area is about seven times that of the latter. At the center of the deepest tropical or Antarctic ozone hole, approximately 80% of the normal ozone value is depleted, whereas annual mean ozone depletion in the lower stratosphere over the tropics due to the coldest temperature is about 1.6 times that over Antarctica and is about 7.7 times that over the Arctic. The whole-year ozone hole over the tropics could cause a serious global concern as it can lead to increases in ground-level ultraviolet radiation and affect 50% of Earth's surface area, which is home to approximately 50% of the world's population. Moreover, since ozone loss is well-known to lead to stratospheric cooling, the presence of the all-season tropical ozone hole and the seasonal polar ozone holes is equivalent to the formation of three ‘temperature holes’ in the global lower stratosphere. These findings will play a far-reaching role in understanding fundamental atmospheric processes and global climate change.

Short term prediction of atmospheric temperature using neural networks

In this paper, a neural network based forecasting model for the maximum and the minimum temperature for the ground level is proposed. A backpropagation method of gradient-decent learning in multi-layer perceptron (MLP) type of neural network with only one hidden layer is considered. This network consists of 25 input nodes and two output nodes. The network is trained with a varying number of nodes in the hidden layer using a set of training sample and each of them is tested with a set of test sample. It accepts previous two consecutive days information (such as pressures, temperatures, relative humidities, etc.) as inputs for the estimation of the maximum and the minimum temperature as output. The network with 20 or less neurons in the hidden layer is found to be "optimum" and it produces an error within ±2° C for 80% of test cases.

Microhabitat Associations for the Threatened Cheat Mountain Salamander in Relation to Early-stage Red Spruce Restoration Areas

The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal non-detection sites. We found that soil pH was higher and soil moisture was lower at spruce restoration sites compared to the occupied site, and that light intensity, sub-canopy air temperature, and ground-level air temperature were higher in spruce restoration prescriptions with reduced canopy cover. We found that soil moisture was higher at occupied sites compared to proximal non-detection sites, but soil pH was not significantly different. Our study suggests that Cheat Mountain salamanders are associated with low soil pH and high soil moisture, and thus spruce restoration could enhance habitat quality for this species in the long-term.

Large crop production losses induced by global ozone stress based on interval evaluation

Global crop yield loss due to ground-level ozone (O3) concentrations is a major challenge to food security, but a dose-response association is not easy to quantify. Here, we propose using a new metric, O3 sensitivity of crop yield (Yo), to estimate yield loss under different O3 time intervals using four observational databases. The Yo metric shows a non-linear parabola with elevated atmospheric O3 for wheat, maize, rice, soybean, and assorted vegetables. Spatial heterogeneity of yield loss varies as a function of crop type and O3 intervals. Estimates of yield loss from ozone suggest recent losses (2017-2019) may reach as high as 537 million tonnes, with a significant proportion coming with lower (30-40 ppb) exposure (325 million tonnes). Our results suggest that previous research, which only included higher (>40 ppb ozone), may have had grossly underestimated the negative effect of atmospheric O3 on crop production. Suppose these results are endemic to global crop production. In that case, additional research will be necessary to reassess ozone sensitivity and dose-responses, both spatially and temporally, to determine future air pollution impacts.

Student leadership programme: igniting the young minds

Learning outcomes This case will help students to understand the following: Develop a basic understanding of competency building processes. Learn about the mentoring process and its application in leadership development. Develop awareness about the methodology for assessment of the effectiveness of training. Case overview/synopsis Dr A. R. K. Pillai founded the Indian Leprosy Foundation in 1970 in response to the national call by late Mrs Indira Gandhi, prime minister of India, to the public-spirited people to take up leprosy eradication. It collaborated with international agencies to reduce leprosy drastically in India from four million, in 1982 to around a hundred thousand cases in 2006. In 2006, the Indian Leprosy Foundation was renamed as Indian Development Foundation (IDF) as the trustees decided to expand the work of IDF in the areas of health, children’s education and women’s empowerment. Dr Narayan Iyer, Chief Executive Officer (CEO) of IDF initiated a leadership development intervention called the Students’ leadership programme (SLP) for children in the age group of 12 to 14, from the urban poor households in 2014. It was a structured mentoring programme spanning over three months in collaboration with the schools. It aimed at incubating skills in the areas of leadership, teamwork, personality, behavioural traits and provided career guidance. It had a humble beginning in 2014 with a coverage of 50 students. Initially, IDF welcomed executives from the corporate sector as mentors. As there was a need to rapidly expand the scope of SLP to the other cities of India, IDF tied up with the graduate colleges and invited the students to be the mentors. The other objective behind this move was to create social awareness among the students from more affluent strata of society. IDF was able to dramatically increase the participation of the students through SLP by approximately up to 100,000 by 2020. However, rapid progress threw up multiple challenges. The teachers complained about the non-availability of the students for regular classes to teach the syllabus as the students were busy with SLP. The schools forced IDF to shorten the duration of SLP to two months. Also, many undergraduate mentors were unable to coach the participants due to lack of maturity and found wanting to strike a rapport with them. There was a shortage of corporate executives who volunteered for the mentoring, due to work pressures. Dr Narayan, CEO & National Coordinator and Ms Mallika Ramchandran, the project head of SLP at IDF, were worried about the desired impact of SLP on the participants and its sustainability due to these challenges. So, with the support of Dr Narayan, she initiated a detailed survey to assess the ground-level impact of SLP. The objective was to get clarity about what was working for SLP and what aspects needed to improve, to make the programme more effective. Overall feedback from the survey was very positive. The mothers had seen very positive changes in the participants’ behaviour post-SLP. The teachers had specific concerns about the effectiveness of undergraduate mentors. The need for a refresher course to inculcate ethical behaviour and the inadequacy of the two-month duration of the SLP to reinforce values were highlighted. Respondents also voiced the requirement to build responsible citizenship behaviours among the participants. Mallika was all for preparing a model to further enhance the effectiveness of SLP. Dr Narayan and Mallika embraced the challenge and they were raring to go to develop SLP as a cutting-edge leadership programme and to take it to new heights. Complexity academic level This case can be used in courses on human resource management in postgraduate and graduate management programmes. It can also be used in the general and development management courses and during executive education programmes to teach methodologies for evaluating the effectiveness of the training interventions, with emphasis on the voluntary sector. Supplementary materials Teaching notes are available for educators only. Subject code CSS 6: Human Resource Management.

The Effects of Virtual Height Exposure on Postural Control and Psychophysiological Stress Are Moderated by Individual Height Intolerance

Virtual reality (VR) enables individuals to be exposed to naturalistic environments in laboratory settings, offering new possibilities for research in human neuroscience and treatment of mental disorders. We used VR to study psychological, autonomic and postural reactions to heights in individuals with varying intensity of fear of heights. Study participants (N = 42) were immersed in a VR of an unprotected open-air elevator platform in an urban area, while standing on an unstable ground. Virtual elevation of the platform (up to 40 m above the ground level) elicited robust and reliable psychophysiological activation including increased distress, heart rate, and electrodermal activity, which was higher in individuals suffering from fear of heights. In these individuals, compared with individuals with low fear of heights, the VR height exposure resulted in higher velocity of postural movements as well as decreased low-frequency (<0.5 Hz) and increased high-frequency (>1 Hz) body sway oscillations. This indicates that individuals with strong fear of heights react to heights with maladaptive rigidity of posture due to increased weight of visual input for balance control, while the visual information is less reliable at heights. Our findings show that exposure to height in a naturalistic VR environment elicits a complex reaction involving correlated changes of the emotional state, autonomic activity, and postural balance, which are exaggerated in individuals with fear of heights.

Trends of Ground-Level Ozone in New York City Area during 2007–2017

The spatiotemporal patterns of ground level ozone (O3) concentrations in the New York City (NYC) metropolitan region for the 2007–2017 period were examined conjointly with local emissions of O3 precursors and the frequency of wildfires. Daily 8-h and 1-h O3 and nitric oxide (NO) concentrations were retrieved from the US Environmental Protection Agency (EPA) Air Data. Annual emission inventories for 2008 and 2017 were acquired from EPA National Emissions Inventory (NEI). The number and area burnt by natural and human-ignited wildfires were acquired from the National Interagency Fire Center (NIFC). The highest daily 8-h max O3 concentrations varied from 90 to 111 parts per billion volume (ppbv) with the highest concentrations measured perimetrically to NYC urban agglomeration. The monthly 8-h max O3 levels have been declining for most of the peri-urban sites but increasing (from +0.18 to +1.39 ppbv/year) for sites within the urban agglomeration. Slightly higher O3 concentrations were measured during weekend than those measured during the weekdays in urban sites probably due to reduced O3 titration by NO. Significant reductions of locally emitted anthropogenic nitrogen oxides (NOx) and volatile organic compounds (VOCs) may have triggered the transition from VOC-limited to NOX-limited conditions, with downwind VOCs sources being critically important. Strong correlations between the monthly 8-h max O3 concentrations and wildfires in Eastern US were computed. More and destructive wildfires in the region were ignited by lightning for years with moderate and strong La Niña conditions. These findings indicate that climate change may counterbalance current and future gains on O3 precursor’s reductions by amending the VOCs-to-NOx balance.

Winter Wheat Nitrogen Estimation Based on Ground-Level and UAV-Mounted Sensors

A better understanding of wheat nitrogen status is important for improving N fertilizer management in precision farming. In this study, four different sensors were evaluated for their ability to estimate winter wheat nitrogen. A Gaussian process regression (GPR) method with the sequential backward feature removal (SBBR) routine was used to identify the best combinations of vegetation indices (VIs) sensitive to wheat N indicators for different sensors. Wheat leaf N concentration (LNC), plant N concentration (PNC), and the nutrition index (NNI) were estimated by the VIs through parametric regression (PR), multivariable linear regression (MLR), and Gaussian process regression (GPR). The study results reveal that the optical fluorescence sensor provides more accurate estimates of winter wheat N status at a low-canopy coverage condition. The Dualex Nitrogen Balance Index (NBI) is the best leaf-level indicator for wheat LNC, PNC and NNI at the early wheat growth stage. At the early growth stage, Multiplex indices are the best canopy-level indicators for LNC, PNC, and NNI. At the late growth stage, ASD VIs provide accurate estimates for wheat N indicators. This study also reveals that the GPR with SBBR analysis method provides more accurate estimates of winter wheat LNC, PNC, and NNI, with the best VI combinations for these sensors across the different winter wheat growth stages, compared with the MLR and PR methods.

Measurement of Energy Spectrum and Elemental Composition of PeV Cosmic Rays: Open Problems and Prospects

Cosmic rays represent one of the most important energy transformation processes of the universe. They bring information about the surrounding universe, our galaxy, and very probably also the extragalactic space, at least at the highest observed energies. More than one century after their discovery, we have no definitive models yet about the origin, acceleration and propagation processes of the radiation. The main reason is that there are still significant discrepancies among the results obtained by different experiments located at ground level, probably due to unknown systematic uncertainties affecting the measurements. In this document, we will focus on the detection of galactic cosmic rays from ground with air shower arrays up to 1018 eV. The aim of this paper is to discuss the conflicting results in the 1015 eV energy range and the perspectives to clarify the origin of the so-called `knee’ in the all-particle energy spectrum, crucial to give a solid basis for models up to the end of the cosmic ray spectrum. We will provide elements useful to understand the basic techniques used in reconstructing primary particle characteristics (energy, mass, and arrival direction) from the ground, and to show why indirect measurements are difficult and results are still conflicting.