Tropospheric Levels Research Articles

Role of land-ocean interactions in stepwise Northern Hemisphere Glaciation

The investigation of triggers causing the onset and intensification of Northern Hemisphere Glaciation (NHG) during the late Pliocene is essential for understanding the global climate system, with important implications for projecting future climate changes. Despite their critical roles in the global climate system, influences of land-ocean interactions on high-latitude ice sheets remain largely unexplored. Here, we present a high-resolution Asian dust record from Ocean Drilling Program Site 1208 in the North Pacific, which lies along the main route of the westerlies. Our data indicate that atmosphere-land-ocean interactions affected aeolian dust emissions through modulating moisture and vegetation in dust source regions, highlighting a critical role of terrestrial systems in initiating the NHG as early as 3.6 Myr ago. Combined with additional multi-proxy and model results, we further show that westerly wind strength was enhanced, mainly at low-to-middle tropospheric levels, during major glacial events at about 3.3 and 2.7 Myr ago. We suggest that coupled responses of Earth’s surface dynamics and atmospheric circulation in the Plio-Pleistocene likely involved feedbacks related to changes in paleogeography, ocean circulation, and global climate.

Wpływ zmian klimatu na środowisko zabudowane

We are currently in the period of an intensive climate change, resulting from changes in the heat balance of the earth’s surface and causing an increase in the temperature of the lower troposphere levels. According to the latest IPCC report of 2021, it is human activity that has indisputably caused the increase in atmospheric concentrations of greenhouse gases, responsible for this process. The consequences of climate change under Polish conditions, apart from a rise in temperature especially in the spring and winter months, are also changes in the amount and distribution of precipitation totals. A slight increase in precipitation totals is observed, however heavy rainfall is significantly more frequent, interspersed with periods of droughts and heatwaves. Ground frost-free periods are prolonged, and a negative trend in the duration and thickness of snow cover is recorded in most parts of the country. Although extreme phenomena occurring in Poland are permanently inscribed in its climatic conditions, the threat of strong winds has been increasing in recent years, and the intense precipitation that often accompanies them is the cause of peak discharges and flooding. Forecasts for progressive climate change are not optimistic, either on a global scale or for the country in question. The article examines the impact of climate change on the design, construction and maintenance of engineering structures globally and for Poland. Changes in design standards, selected examples of disasters and solutions to adapt and build resilience to climate change have been analysed. For most building disasters, climatic factors were the direct cause of the disaster, although in the course of the analysis it has usually turned out that the disasters exposed human errors in the design, construction and, to a lesser extent, the improper maintenance of engineering structures. However, there is an increasing number of new approaches to creating a climate change resilient built environment, including the latest one, which proposes to use the grey infrastructure of cities to build resilience to climate change.

TEOS-10 Equations for Determining the Lifted Condensation Level (LCL) and Climatic Feedback of Marine Clouds

At an energy flux imbalance of about 1 W m−2, the ocean stores 90% of the heat accumulating by global warming. However, neither the causes of this nor the responsible geophysical processes are sufficiently well understood. More detailed investigations of the different phenomena contributing to the oceanic energy balance are warranted. Here, the role of low-level marine clouds in the air–sea interaction is analysed. TEOS-10, the International Thermodynamic Equation of State of Seawater—2010, is exploited for a rigorous thermodynamic description of the climatic trends in the lifted condensation level (LCL) of the marine troposphere. Rising sea surface temperature (SST) at a constant relative humidity (RH) is elevating marine clouds, cooling the cloud base, and reducing downward thermal radiation. This LCL feedback effect is negative and counteracts ocean warming. At the current global mean SST of about 292 K, the net radiative heat flux from the ocean surface to the LCL cloud base is estimated to be 24 W m−2. Per degree of SST increase, this net flux is expected to be enhanced by almost 0.5 W m−2. The climatic LCL feedback effect is relevant for the ocean’s energy balance and may be rigorously thermodynamically modelled in terms of TEOS-10 equations. LCL height may serve as a remotely measured, sensitive estimate for the sea surface’s relative fugacity, or conventional relative humidity.

On the relation of CMIP6 GCMs errors at RCM driving boundary condition zones and inner region for Central Europe region

Global climate models (GCMs) are essential for studying the climate system and climate change projections. Due to their coarse spatial resolution, downscaling is necessary on the regional scale. Regional climate models (RCMs) represent a standard solution for this issue. Nevertheless, the boundary conditions provided by GCMs unavoidably influence the outputs of RCMs. This study evaluates CMIP6 GCMs regarding the variables relevant to RCM boundary conditions. Particular focus is on the simulation of CNRM-ESM2-1, which is being used as a driving model for convection-permitting ALARO-Climate RCM, used as one source feeding new Czech climate change scenarios. The analysis is conducted over the boundaries and inside the RCM integration domain. Firstly, an evaluation of CFSR and ERA5 reanalyses against radiosondes is performed to choose an appropriate reference dataset for upper air variables. A high correlation between the two studied reanalysis and radiosondes was revealed, and it slightly decreases at the upper tropospheric levels. ERA5 is then chosen as the reference for the boundary analysis. Over the inner region, the simulated mean annual cycle of impact-relevant variables is validated against E-OBS. The CNRM-ESM2-1 performs well regarding near-surface variables over the Czech Republic, but it exhibits larger errors along the boundaries, especially for air temperature and specific humidity. The GCM performance in simulating the upper air atmospheric variables used as RCM boundary conditions relates rather weakly to the GCM performance in simulating the near-surface parameters in the inner region in terms of parameters relevant for impact studies.

Upper‐level wind mode over the North Atlantic‐Arctic Ocean leading to coherent variations of Eurasian and North American winter temperatures and weakness in the CMIP6 models

AbstractThis study discovers that the interannual synchronization of winter temperature anomalies between northern Eurasia and North America is closely related to variation in the second leading mode of the 300 hPa meridional wind anomalies (i.e., V300‐EOF2) over the North Atlantic‐Arctic Ocean. The V300‐EOF2 mode modulates the large‐scale Rossby wave propagating across the mid‐high latitudes of the Eurasian and North American continents at the mid‐high level of troposphere, and it also interferes with the climatological quasi‐stationary wavenumber‐2 to affect the stratosphere circulation, which facilitates the southward intrusion of cold air into Eurasia and North America simultaneously. This study also evaluated whether the CMIP6 high‐top (HT) models could more accurately represent the V300‐EOF2 mode and the associated modulation mechanism on synchronized temperature variation between Eurasia and North America than the low‐top (LT) models. The results demonstrate that although the multi‐model ensemble means (MME) of both the HT and LT models can reproduce the V300‐EOF mode, they all underestimate its modulation mechanism on atmospheric circulation and coherent temperature changes over mid‐latitude Eurasia and North America, with minor differences in simulation skill capability. Most importantly, although containing a full stratosphere, the HT models do not significantly improve their simulation ability to depict the observed linear interference between the anomalous wave‐2 and the climatological stationary wave‐2 compared to the LT models. Therefore, comparing to the LT models, the CMIP6 HT models present no clear advantages in reproducing the V300‐EOF2 mode and its associated low‐frequency climate anomalies. These results also have implications for the evaluation of the predictability of concomitant Eurasian‐North American cooling in the Subseasonal‐to‐Seasonal Prediction Project.

NO2 Concentration Estimation at Urban Ground Level by Integrating Sentinel 5P Data and ERA5 Using Machine Learning: The Milan (Italy) Case Study

The measurement of atmospheric NO2 pollution concentrations has become a critical topic due to its impact on human health. Ground sensors are the most popular method for measuring atmospheric pollution, but they can be expensive to purchase, install, and maintain. In contrast, satellite technology offers global coverage but typically provides concentration estimates at the tropospheric level, not at the ground level where most human activities take place. This work presents a model that can be used to estimate NO2 ground-level concentrations in metropolitan areas using Sentinel-5P satellite images and ERA5 meteorological data. The primary goal is to offer a cost-effective solution for Low- and Medium-Income Countries (LMICs) to assess air quality, thereby addressing the air quality measurement constraints. To validate the model’s accuracy, study points were selected in alignment with the Regional Agency for the Environment Protection (ARPA) NO2 sensor network in the Metropolitan City of Milan. The results showed that the RMSE of the model estimations was significantly lower than the standard deviation of the real measurements. This work fills the gaps in the literature by providing an accurate estimation model of NO2 in the Metropolitan City of Milan using both satellite data and ERA5 meteorological data. This work presents as an alternative to ground sensors by enabling more regions to assess their air quality effectively.

An intense narrow equatorial jet in Jupiter’s lower stratosphere observed by JWST

The atmosphere of Jupiter has east–west zonal jets that alternate as a function of latitude as tracked by cloud motions at tropospheric levels. Above and below the cold tropopause at ~100 mbar, the equatorial atmosphere is covered by hazes at levels where thermal infrared observations used to characterize the dynamics of the stratosphere lose part of their sensitivity. James Webb Space Telescope observations of Jupiter in July 2022 show these hazes in higher detail than ever before and reveal the presence of an intense (140 m s−1) equatorial jet at 100–200 mbar (70 m s−1 faster than the zonal winds at the cloud level) that is confined to ±3° of the equator and is located below stratospheric thermal oscillations that extend at least from 0.1 to 40 mbar and repeat in multiyear cycles. This suggests that the new jet is a deep part of Jupiter’s Equatorial Stratospheric Oscillation and may therefore vary in strength over time.

Assessment of tropospheric ozone simulations in a regional chemical transport model using GEOS-Chem outputs as chemical boundary conditions

Regional chemical transport models (e.g., Community Multiscale Air Quality (CMAQ) Modeling System) are widely used to simulate the physical and chemical process of regional ozone (O3) pollution and its variation trend in recent years. However, chemical boundary condition (CBC) is an important input of these models and contributes to the model bias against observations. In this study, we develop a tool named GC2CMAQ that provides the CMAQ model with the CBCs from the GEOS-Chem simulation. Two experiments using different CBCs were conducted to evaluate their effect on seasonal O3 simulation in China. The Default experiment utilized the model-default static condition (the relatively clean atmosphere in the eastern United States), and the GC experiment employed the GEOS-Chem simulation results. Compared with the observation, the GC experiment has a much better performance in reproducing elevated O3 levels in the higher troposphere and lower stratosphere during different seasons. Near the earth's surface, the simulated concentrations of pollutants O3 (and PM2.5) in the GC experiment were also closer to the observation in April and July. The accuracy of simulation results in provinces close to the boundary was improved by approximately 20 %–30 % relative to the Default experiment. The CBCs provided by GEOS-Chem enabled a better simulation of stratosphere-troposphere O3 exchange in late spring and early summer, which then affected the pollutant concentration near surfaces through vertical transport. This finding was confirmed by a case study in southwestern Tibet on April 28, 2017, in which we quantified the contributions of different physical and chemical processes to O3 variations at different altitudes using the process analysis method. This study highlights the importance of using a reliable CBC for the regional chemical transport model to derive a better performance of O3 simulation.

Year-long ground-based observations of bromine oxide over Bharati Station, Antarctica

Bromine chemistry plays an important role in tropospheric ozone depletion events in polar regions. Autocatalytic reactions lead to bromine explosion events, causing ozone depletion to near-zero levels in the polar troposphere. Bromine chemistry over Antarctica is not fully understood, and ground-based observations are scarce. This work presents year-long observations of bromine oxide (BrO) over the Bharati station (69.41°S, 76.19°E) using Multi-axis Differential Optical Absorption Spectroscopy (MAX-DOAS) from December 2018 to February 2020. The results show that elevated BrO mixing ratios were found during spring (September), with a maximum value of 10.21 ± 4.38 pptv for clear sky conditions and 33.15 ± 2.23 pptv for cloudy conditions. BrO was not observed above the detection limit (∼3 × 1013 molecule cm−2) outside spring on clear days. In general, lower mixing ratios were observed on clear days over Bharati compared to stations in West Antarctica. This indicates a different source strength over East Antarctica compared to West Antarctica. BrO vertical column densities were high during spring, with a maximum value of 1.34 ± 0.35 × 1014 molecule cm−2. The vertical profiles of the BrO mixing ratios show a peak at the surface during spring (average of 6.5 ± 1.91 pptv), decreasing sharply with altitude. Back trajectories show that air masses passing over the first year ice showed higher BrO, although factors such as meteorology play an important role in determining the absolute levels. Using a box model, we show that bromine chemistry can deplete as much as 2.15 ppb of ozone in a day at the Bharati Station on clear days, which shows that it does not lead to complete ozone depletion events over Bharati.

The link between European warm-temperature extremes and atmospheric persistence

Abstract. We investigate the link between warm-temperature extremes in Europe and the persistence of large-scale atmospheric-circulation patterns for both winter and summer, along with some possible physical mechanisms connecting the two. We assess atmospheric persistence, leveraging concepts from dynamical systems theory, and reconcile this approach with the more conventional meteorological views of persistence. We find that wintertime warm spells are partly associated with persistent zonal advection at the surface level but display no statistically significant persistence anomaly in the mid-troposphere. For summertime heatwaves, we find a weak yet significant link to anomalously persistent circulation patterns in the mid-troposphere, while there are few significant persistence anomalies of the surface circulation pattern. We further find no evidence of a strong warm-temperature advection signal. This suggests that other radiative and dynamical processes, for example sensible heating and adiabatic warming, as well as local effects, could play a more important role than large-scale warm-temperature advection for these events. We thus argue that persistent atmospheric configurations are not a necessary requirement for warm-temperature extremes and that the results depend to a considerable extent on region and tropospheric level.

Horizontal gravity disturbance vector in atmospheric dynamics

All meteorological and oceanographic textbooks unintentionally define the Earth gravitation outside the solid Earth through treating the Earth as a point-mass located at the Earth center containing the entire Earth mass or assuming the Earth with uniform mass density. Combination of such simplified gravitational and centrifugal accelerations leads to the effective gravity geff. The geopotential surface corresponding to geff (called the effective geopotential surface) is the ellipsoidal surface. The true Earth gravitation outside the solid Earth is the volume integration of gravitation of all point-masses inside the Earth. Combination of true gravitational and centrifugal accelerations leads to the true gravity g. The geopotential surface corresponding to g (called the true geopotential surface) and respect to the Earth ellipsoidal reference surface is the geoid, which varies approximately from -106 m to 86 m worldwide. The true gravity g minus the effective gravity geff is the gravity disturbance vector, δg = g – geff, which is a major variable in geodesy and solid Earth dynamics. Contrarily, δg is neglected completely in dynamics of atmosphere and ocean. In this study, the true gravity g replaces the effective gravity geff in atmospheric dynamic equations. Seven non-dimensional numbers are proposed to identify the magnitude of horizontal gravity disturbance vector (δg)⊥versus traditional horizontal forcing terms such as pressure gradient force and Coriolis force. These non-dimensional numbers are calculated from two publicly available and independent datasets with the geoid undulation (N) from the static gravity field model EIGEN-6C4 and long-term mean geopotential height (Z), wind velocity (u, v), and temperature (T) at 12 pressure levels in troposphere from the NCEP/NCAR reanalyzed climatology. The results demonstrate (δg)⊥ nonnegligible in hydrostatic equilibrium, geostrophic wind, geostrophic vorticity, Q vector, and Omega equation.

An Overview of Stratospheric Ozone and Climate Effects

Anthropogenic Chlorofluorocarbons (CFCs) compelled stratospheric ozone reduction is one of the significant global environmental issues of this era. Ozone acts as a life saviour in the stratosphere whereas the same plays a role as a secondary air pollutant at tropospheric levels. This review encompasses studies involving the science of ozone destruction with an emphasis on chemical processes involved, minimum ozone features, ozone hole area characteristics, various Ozone Depleting Substances (ODSs), consequences of reduced stratospheric ozone levels, and the different executed international commitments to restrain ozone depletion. It has been perceived that the decrease in stratospheric ozone volume gives away extensively to climate change such as through ozone chemistry fluctuations of polar annular modes and its Greenhouse Gas (GHG) features. Different international ozone layer protection agreements have been performing a major role in limiting stratospheric ozone depletion thereby its adverse effects, and specifically Montreal protocol has been a great success to this point.

Extreme Hydrological Events in January 2022: A Case Study over Telangana and Andhra Pradesh State, India

The study will look at extreme rainfall events in Andhra Pradesh and Telangana, where both the monsoon and post-monsoon seasons significantly contribute to rainfall. The winter season 2022 was highlighted by unusual rainfall in some districts of Andhra Pradesh and Telangana in the 2nd week of January 2022, causing significant damage. In this paper, we identify the observational aspects, main synoptic system, physical process, and thermodynamic features leading to such unusual rainfall during the winter season. According to the study's findings, a hailstorm was recorded over Telangana state on January 13, 2022, heavy rain fell in Telangana due to the most active western disturbance as a cyclonic circulation over Rajasthan and Pakistan; on January 14, 2022, heavy to very heavy rain fell in Vizianagaram (16 cm) due to the convergence of winds from the Arabian Sea and Bay of Bengal at lower tropospheric levels over east and adjoining central India and a trough from north interior Karnataka to north interior Odisha. The diurnal and temporal pattern of the hail storm and heavy rainfall over the Andhra Pradesh and Telangana States shows that late evenings are most conducive for the occurrence of extreme rainfall events due to the accumulation of precipitable water.

Microbial Diversity in Rainwater with Correspondence to Particulate Matter and Environmental Factors

Microbial composition in rainwater has emerged as a trending research topic due to the increased use of rainwater harvesting systems (RWHS) worldwide. Studies have been conducted to analyze potentially pathogenic microorganisms in RWHS. However, the core focus in most papers has been on the rainwater collected in the storage tanks rather than the composition of microorganisms in fresh rainwater. Due to the microbial influence on air quality, this review dissects various studies that have identified the types of microorganisms in rainwater and their correspondence with atmospheric microbiota to understand airborne microbial movement and its effect. Current methods for rainwater analysis and technologies such as air mass models, that map the distribution of airborne microorganisms throughout the atmosphere, were evaluated to define factors that allow these organisms to move through different levels of the atmosphere. Additionally, the correlation between organisms found in rainwater and particulate matter was analyzed. This review discusses the importance of analyzing rainwater directly without limiting it to RWHS, like roof-harvested rainwater, in microbial source tracking. The paper also presents an overview of ecological contributions by microorganisms at a tropospheric level. Research gaps were noted in identification techniques, the type of microorganisms studied, and their ecological purposes, including paucity in viral detection. The uniqueness of this review is that potential new techniques were explored for prospective studies to improve and further analyze the microbial communities in rainwater. The more focus we give to microbial communities in fresh rainwater in the future, the easier it will be to predict the levels of pathogenicity and disease transmission related to airborne microbiota.

Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H2)

Abstract. Molecular hydrogen, H2, is one of the most abundant trace gases in the atmosphere. The main known chemical source of H2 in the atmosphere is the photolysis of formaldehyde and glyoxal. Recent laboratory measurements and ground-state photochemistry calculations have shown other aldehydes photodissociate to yield H2 as well. This aldehyde photochemistry has not been previously accounted for in atmospheric H2 models. Here, we used two atmospheric models to test the implications of the previously unexplored aldehyde photochemistry on the H2 tropospheric budget. We used the AtChem box model implementing the nearly chemically explicit Master Chemical Mechanism at three sites selected to represent variable atmospheric environments: London, Cabo Verde and Borneo. We conducted five box model simulations per site using varying quantum yields for the photolysis of 16 aldehydes and compared the results against a baseline. The box model simulations showed that the photolysis of acetaldehyde, propanal, methylglyoxal, glycolaldehyde and methacrolein yields the highest chemical production of H2. We also used the GEOS-Chem 3-D atmospheric chemical transport model to test the impacts of the new photolytic H2 source on the global scale. A new H2 simulation capability was developed in GEOS-Chem and evaluated for 2015 and 2016. We then performed a sensitivity simulation in which the photolysis reactions of six aldehyde species were modified to include a 1 % yield of H2. We found an increase in the chemical production of H2 over tropical regions where high abundance of isoprene results in the secondary generation of methylglyoxal, glycolaldehyde and methacrolein, ultimately yielding H2. We calculated a final increase of 0.4 Tg yr−1 in the global chemical production budget, compared to a baseline production of ∼41 Tg yr−1. Ultimately, both models showed that H2 production from the newly discovered photolysis of aldehydes leads to only minor changes in the atmospheric mixing ratios of H2, at least for the aldehydes tested here when assuming a 1 % quantum yield across all wavelengths. Our results imply that the previously missing photochemical source is a less significant source of model uncertainty than other components of the H2 budget, including emissions and soil uptake.

24 h Evolution of an Exceptional HONO Plume Emitted by the Record-Breaking 2019/2020 Australian Wildfire Tracked from Space

Megafires occurred in Australia during the 2019/2020 bushfire season, leading to enhanced concentrations of many tropospheric pollutants. Here, we report on a fire plume with unusually high and persistent nitrous acid (HONO) levels that we could track during one day at free tropospheric levels over the Tasman Sea on 4 January 2020 using IASI and CrIS satellite observations. HONO concentrations up to about 25 ppb were retrieved during nighttime. Persistent HONO concentrations (>10 ppb) were still observed at sunrise, likely due to large aerosol concentrations within the plume, preventing HONO photodissociation. In addition, comparison with carbon monoxide (CO) measurements suggest a secondary production during the plume transport. Model simulations confirm that the plume is transported in the lower free troposphere with concentrations as high as 30 ppb at about 4 km. However, many uncertainties and unknowns remain in the plume aerosol load and in the chemical processes which may explain the model inability to reproduce elevated HONO concentrations at sunrise.

Behavior of the ITCZ second band near the Peruvian coast during the 2017 coastal El Niño

The behavior of the second band of the Intertropical Convergence Zone (ITCZ) near the Peruvian coast during early 2017 is studied, using precipitation, surface winds, sea surface temperature (SST) and atmospheric variables in different isobaric levels. The proposal of a daily index (Ia) to identify opportunely the formation of this band and the Lorenz energy terms in the region is also considered. This band was present from late January to early April 2017, associated with an anomalous dipole of sea level pressure between the east and west eastern Equatorial Pacific that configured anomalously northerly surface winds and the release of southeasterly trade winds near Peru. In medium levels, a zonally oriented positive mixing ratio anomaly was observed in early March over the ITCZ second band, associated with heavy rain systems over the northern Peruvian coastal region. In the same period, positive anomalies of divergence in high tropospheric levels were observed. The daily Ia index allowed an effective detection of the ITCZ second band 11 days before the maximum coastal precipitation, and the Lorenz energy terms showed eddy kinetic energy (KE) peaks in January and February and a contribution of barotropic instability in equatorial regions.

Topographical and Thermal Forcing in Favorable Circulation Pattern to Early Spring Precipitation over the Southeastern Tibetan Plateau

During the boreal spring (March–May), the precipitation that occurs from March over the southeastern Tibetan Plateau (TP) can account for 20–40% of the total annual amount. The origin of this phenomenon has not been clearly understood from a climatological perspective. In this study, the role of topographical and thermal forcing on the precipitation over the southeastern TP in early spring (March) was investigated through sensitivity numerical simulations based on general circulation model. The simulated results show the favorable circulation and static stability to early spring precipitation over the southeastern TP when the model is simultaneously forced by realistic topography, zonal symmetric radiative equilibrium temperature, and diabatic heating over the TP and its surrounding areas. The quasi-stationary wave pattern over the Eurasian continent forced by realistic and TP topographical forcing leads to prolonged low pressure and intensified zonal winds over the southeastern TP due to quasi-steady wave activities. Thermal forcing experiments reveals that sensible heating over the southeastern TP not only strengthens the cyclonic circulation, ascending motion and statically unstable over the southeastern TP through thermal adaptation and the Sverdrup balance, but also triggers an anticyclone at upper tropospheric level extending from north of the Bay of Bengal to the eastern TP, which further favors precipitation over the southeastern TP. This work will provide useful background information for spring climate prediction over the TP.

The effects of tropospheric ozone on plant species: New perspectives

The effect of tropospheric ozone on the physiology of plants has been well established using physicochemical analysis and visual assessment. One of the main metabolic processes, in plants that is affected by ozone, is photosynthesis. This in turn affects a number of secondary processes required for the survival of plants. This study focused on two main aspects; the qualitative determination of damage through visual assessment and the quantification of damage through the determination of the content of chlorophyll and other quality parameters using spectrophotometric techniques in a number of plant species. Three distinct setups were considered, mainly rural, urban and semiurban, representing the topography of the islands of Malta and Gozo. It was observed that chlorosis was not the sole factor contributing to the yellowing of the leaves. Another important finding was the correlation between ozone levels (50.18-69.35 ppb) and the anthocyanin content (2.57-28.99 mg/kg) of leaves. From the three plant species that were extensively studied (Nerium oleander, Pinus halepensis and Schinus terebinthifolius), the N. oleander exhibited promising results as a bioindicator for ozone-induced damage. Due to the presence of this ornamental plant in rural and urban areas, it can be used by researchers and authorities as a tool for assessment of tropospheric ozone levels.

Detection of the impact of a tropical cyclonic system on the dynamics and energetics of the atmosphere using wind profiler radar

Rapid changes in the tropospheric circulation features associated with the overhead passage of the Gaja cyclonic system over the 205 MHz Stratosphere Troposphere wind profiler radar observations at Kochi (10.03° N, 76.33° E), India, have been studied. The severe cyclonic system formed in the southeast Indian Peninsular region weakened into a depression after landfall near the Tamil Nadu coast. On 16th November 2018, the cyclonic system crossed the Western Ghats and travelled westward at 33 knots over the ST radar site at Kochi in the evening. Later it reached the Arabian Sea and intensified again into a severe cyclone. Continuous observations of the vertical structure of the wind pattern at 4-min intervals from the wind profiler radar have been examined. The impact of the transit of the cyclonic system extends up to a height of 13 km in the atmosphere. The vertical distribution of turbulent kinetic energy in the atmosphere indicates a sudden disruption in the tropospheric levels at the time of storm passage. The cyclonic system traversed over the Western Ghats positioned at an altitude of 2500 m. It crossed the radar site at the mean sea level after passing a horizontal distance of 100 km. The abrupt changes in the topographical conditions generate atmospheric gravity waves in the leeward side of the Western Ghats, as observed from the ST radar, are presented. During the period, changes in surface parameters were evaluated using co-located automatic weather station (AWS) data. Satellite information and Doppler weather radar observations from Kochi have also supplemented the investigation.