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Ammannia baccifera L. is a wetland medicinal herb that belongs to the family Lythraceae. This plant is very notable to have a wide scope in pharmacological, therapeutic and medicinal properties. The current examination imparts an effective, proficient and fast strategy of commercial proliferation to satisfy the folklore medicinal and pharmacological demands of the market. A large-scale micropropagation of Ammannia baccifera L was done through a meticulous and a well-organized procedure. The leaf segments were cultured on MS medium augmented with different concentrations (0.5–2.5 mg/l) of 6- benzylaminopurine (BAP), (0.5- 2.0 mg/l) 1- naphthaleneacetic acid (NAA) and (1.0- 2.0 mg/l) 2,4- Dichlorophenoxyacetic acid (2,4-D) and were used for callus initiation. BAP at 1.0 mg/l combined with 0.5 mg/l NAA was found to be the best concentration and combination for initiation of high frequency of reddish green nodular callus (95.00±1.87) and good response for leaf explants. For shoot regeneration, MS medium blended with BAP at 1.5 mg/l and IAA at 0.6 mg/l produces maximum percentage of shoots from the callus derived by leaf explant. The leaf segments produce maximum percentage shoots (90.00±1.52), total number of shoots per explant (26.33±1.45) and length of shoot (9.63±0.73 cm). However, healthy established shoots were cultured on MS medium fortified with 1.5 mg/l indole-3-butyric acid (IBA) along with 2.0 mg/l. Indole-3-acetic acid (IAA) was found to be best for the root initiation and production in the leaf segments (95±1.57), number of roots (19.33±0.88) and root length (8.63±0.61cm). The regenerated plantlets were relocated to paper cups filled with vermiculite:sand:soil in the proportion of 1:2:1 (w/w) and were then transferred into outdoor conditions.

Surface Temperature (ST) is important in terms of surface energy and terrestrial water balances affecting urban ecosystems. In this study, to process the nonlinear changes of climatological variables by leveraging the distinct advantages of Long Short-Term Memory (LSTM) and Bidirectional Long Short-Term Memory (BiLSTM), we propose an LSTM-BiLSTM hybrid deep learning model which extracts multi-dimension features of inputs, i.e., backward (future to past) or forward (past to future) to predict ST. This study assessed the climatological variables, i.e., wind speed, wind direction, relative humidity, dew point temperature, and atmospheric pressure impact on ST using five major coastal cities of India: Chennai, Mangalore, Visakhapatnam, Cuddalore, and Cochin. The Recurrent Neural Networks (RNN) and hybrid LSTM-BiLSTM models have effectively predicted ST and outperformed the standalone Artificial Neural Networks (ANN), LSTM, and BiLSTM models. The RNN and LSTM-BiLSTM models have performed better in predicting ST for Mangalore (Nash-Sutcliffe efficiency (NSE)=0.91), followed by Cochin (NSE=0.89), Chennai (NSE=0.88), Cuddalore (NSE=0.88), and Vishakhapatnam (NSE=0.81). The hybrid data-driven modeling framework indicated that coupling the LSTM and BiLSTM models was proven effective in predicting the ST of coastal cities. HIGHLIGHTS Surface temperature prediction model based on hybrid machine learning algorithms.; Hybrid data-driven algorithm was more effective compared to the individual ML algorithms.; Surface temperature prediction of major coastal cities of India.

Solar eclipse (with maximum obscuration of 85.3% and magnitude of 0.893) occurred on 26 December 2019 during morning hours (08:10 to 11:15 LT with a peak at 09:33 LT) over Gadanki (13.5oN, 79.2oE) has provided a unique opportunity to test the hypothesis of ‘Extended Fumigation Effect’ or ‘Second Fumigation’ on the surface and boundary layer pollutants. To capture this event, a campaign using multi-instrument (AWS, Aethalometer, PM sensors, ceilometer, radiosonde) on multi-platform (surface, surface based remote sensing, drone, tethered balloon, in-situ balloon) was conducted. Eclipse obscuration caused decrease in surface temperature by 4.3 °C around 10:00 LT. Boundary layer remained shallow until 09:00 LT (between 500 m and 900 m) but near the termination of the eclipse and soon after the termination a convective boundary layer showed a rapid increase to above 1 km within a short time (1 h). A Fumigation peak (common phenomenon in normal days) in black carbon occurred with a sharp peak concentration of 9.4 μg/m3 at around 07:00 LT and then started decreasing. However, concentration started to increase unusually again at around 08:20 LT and remained at the range of 4–6 μg/m3instead of a normal decreasing trend, which is about 2–3 times of the mean concentration at this period of time. Similar variation in PM1, PM2.5, and PM10are also observed. Background instability estimated using radiosonde measurements suggests Fumigation, Fumigation/Lofting and Trapping before, during and after the eclipse, respectively.

The Asian Summer Monsoon (ASM) dynamics act as a pathway for the transport of trace gases and pollutants both vertically (through convection) and horizontally (through low-level jet and tropical easterly jet). These pollutants will be trapped in the anticyclone present during the same period in the upper troposphere and lower stratosphere (UTLS). Since the anticyclone extends from the Middle East to East Asia, trapped pollutants are expected to make a large radiative forcing to the background atmosphere. Thus, it is essential to understand the anticyclone features in detail and its relation to long-term oscillations. This work explores the spatial variability and the trends of the Asian Summer Monsoon Anticyclone (ASMA) using observational and reanalysis data sets. Emphasis is made to investigate the temporal, spatial, and long-term trends of ASMA. Our analysis indicates that the spatial extent and magnitude of ASMA is greater during July and August compared to June and September. The decadal variability of the anticyclone is very large at the edges of anticyclone than at the core region. Significant deviations in the northeast and southwest parts of ASMA are also observed in the decadal variability with reference to 1951−1960 period. The strength of the ASMA shows a drastic increase from the easterlies to the westerlies in terms of temporal variation. Further, our results show that the extent of anticyclone is greater during the active phase of the monsoon, strong monsoon years, and during La Niña events. Significant warming with strong westerlies is observed exactly over the Tibetan Plateau during the active phase of the monsoon, strong monsoon years, and during La Niña events. Over the Tibetan Plateau, there is strong elevated heating from the surface to the tropopause, which is observed with strong westerlies during active and strong monsoon years. Our results support the transport process over Tibetan Plateau and the Indian region during active, strong monsoon years and during strong La Niña years. It is suggested to consider different phases of monsoon while interpreting the pollutants/trace gases in the anticyclone.

The Middle East can experience extended wintertime spells of exceptionally hot weather, which can result in prolonged droughts and have major impacts on the already scarce water resources of the region. Recent observational studies point at increasing trends in mean and extreme temperatures in the Middle East, while climate projections seem to indicate that, in a warming weather scenario, the frequency, intensity and duration of warm spells will increase. The nonstationary warm spell frequency analysis approach proposed herein allows considering both climate variability through global climatic oscillations and climate change signals. In this study, statistical distributions with parameters conditional on covariates representing time, to account for temporal trend, and climate indices are used to predict the frequency, duration and intensity of wintertime warm spells in the Middle East. Such models could find a large applicability in various fields of climate research, and in particular in the seasonal prediction of warm spell severity. Based on previous studies linking atmospheric circulation patterns in the Atlantic to extreme temperatures in the Middle East, we use as covariates two classic modes of ‘fast’ and ‘slow’ climatic variability in the Atlantic Ocean (i.e., the Northern Atlantic Oscillation and the Atlantic Multidecadal Oscillation respectively). Results indicate that the use of covariates improves the goodness-of-fit of models for all warm spell characteristics.

This paper deals with the investigation of long-term variability of atmospheric dust over the United Arab Emirates (UAE). The climatology of dust episodes (dust events, dust storms, and severe dust storms) is compiled based on the hourly observations and synoptic codes recorded at four different stations over UAE between the years 1983–2014. The diurnal, temporal, monthly, and inter-annual variations of dust episodes and their relation with the mean wind speed, maximum wind speed, and temperature are discussed. Dust episodes show a clear diurnal variation in all the stations. The duration of dust storms is large compared to dust events. For instance, dust events over the UAE persist for 2–5 h while dust storms last for about 5–11 h. Dust storms also show clear seasonal variability with the maximum occurring during winter and the minimum during summer whereas most of the dust events occur during the months of March and April. The inter-annual variation of dust events shows a significant decrease while dust storms depict a moderate increase over the UAE. The synoptic scale climatology of all dust storms is also analyzed and shows changes in wind direction to the south-west prior to 2 days of the dust storm generation. The climatology of wind direction and wind speed during the dust episode indicates that 90% of dust episodes are coming from the southwest direction. These observed results are discussed in light of the current global warming scenarios with a special emphasis on the role of dust episodes on the regional enhancement of temperature.

Long-term trends of the parameters related to convection and instability obtained from 27 radiosonde stations across six subdivisions over the Indian region during the period 1980–2016 are presented. A total of 16 parcel and instability parameters along with moisture content, wind shear, and thunderstorm and rainfall frequencies have been utilized for this purpose. Robust fit regression analysis is employed on the regional average time series to calculate the long-term trends on both a seasonal and a yearly basis. The level of free convection (LFC) and the equilibrium level (EL) height are found to ascend significantly in all Indian subdivisions. Consequently, the coastal regions (particularly the western coast) experience increases in severe thunderstorms (TSS) and severe rainfall (SRF) frequency in the pre-monsoon period, while the inland regions (especially Central India) experience an increase in ordinary thunderstorms (TSO) and weak rainfall (WRF) frequency during the monsoon and post-monsoon periods. The 16–20-year periodicity is found to dominate the long-term trends significantly compared to other periodicities and the increase in TSS, and convective available potential energy (CAPE) is found to be more severe after the year 1999. The enhancement in moisture transport and associated cooling at 100 hPa along with the dispersion of boundary layer pollutants are found to be the main causes for the increase in CAPE, which leads to more convective severity in the coastal regions. However, in inland regions, moisture-laden winds are absent and the presence of strong capping effect of pollutants on instability in the lower troposphere has resulted in more convective inhibition energy (CINE). Hence, TSO and occurrences of WRF have increased particularly in these regions.

A diagnostic investigation of an extreme rainfall episode that occurred over the central and north Indian region is carried out in this study using data from a suite of observations from space-borne instruments and the reanalysis datasets. This event is unique in the sense that the organized tropical and extratropical forcing stimulated the intense rainfall on 01 Jan 2012. The WindSat (multi-frequency polarimetric microwave radiometer) observations indicate the source of the moisture flux coming from the adjoining tropical Ocean. The dynamical and thermo-dynamical contributions are evaluated based on the atmospheric instability analysis using the Atmospheric Infrared Sounder (AIRS) and reanalysis datasets by computing various stability indices such as total totals (TT) index, Potential Vorticity (PV), static stability and the Convective Available Potential Energy (CAPE). High TT index values (>40 K) are observed both in satellite and reanalysis data indicating thermodynamic instability. PV intrusion to low latitudes is also observed with extreme rainfall occurrence ahead of the PV tongue. The vertical structure of PV intrusion shows remarkable features with enhanced upward motions ahead of the intrusion representing the dynamical instability. The reduced static stability, increased CAPE and upper-level cyclonic anomalies together with enhanced moisture in the lower troposphere coming from the adjoining tropical Indian Ocean regulate the amplitude and region of occurrence of the extreme rainfall. Therefore, this study identifies the significant implications of tropical and extra-tropical influences that generate the thermodynamical and dynamical instabilities for the occurrence of the extreme rainfall event over the Central and Northern parts of India.

The abrupt reduction in the human activities during the first lockdown of the COVID-19 pandemic created unprecedented changes in the background atmospheric conditions. Several studies reported the anthropogenic and air quality changes observed during the lockdown. However, no attempts are made to investigate the lockdown effects on the Atmospheric Boundary Layer (ABL) and background instability processes. In this study, we assess the lockdown impacts on the ABL altitude and instability parameters (Convective Available Potential Energy (CAPE) and Convective Inhibition Energy (CINE)) using WRF model simulations. Results showed a unique footprint of COVID-19 lockdown in all these parameters. Increase in the visibility, surface temperature and wind speed and decrease in relative humidity during the lockdown is noticed. However, these responses are not uniform throughout India and are significant in the inland compared to the coastal regions. The spatial variation of temperature (wind speed) and relative humidity shows an increase and decrease over the Indo Gangetic Plain (IGP) and central parts of India by 20% (100%) and 40%, respectively. Increase (80%) in the ABL altitude is larger over the IGP and central parts of India during lockdown of 2020 compared to similar time period in 2015-2019. This increase is attributed to the stronger insolation due to absence of anthropogenic activity and other background conditions. At the same time, CAPE decreased by 98% in the IGP and central parts of India, where it shows an increase in other parts of India. A prominent strengthening of CINE in the IGP and a weakening elsewhere is also noticed. These changes in CAPE and CINE are mainly attributed to the dearth of saturation in lower troposphere levels, which prevented the development of strong adiabatic ascent during the lockdown. These results provide a comprehensive observation and model-based insight for lockdown induced changes in the meteorological and thermo-dynamical parameters.

Changing patterns in aerosol concentrations over the Asian region is well documented with a concurrent increase over India and a marked reduction over China. However, aerosol vertical distribution in the changing climate is not fully understood. By combining long-term satellite observations from MODIS and CALIOP, here we show rapid changes in the aerosol vertical distribution over the South and East Asia covering India and China. A statistically significant decreasing (increasing) trend in the boundary layer (free troposphere) aerosol concentrations is noticed over India. ERA-Interim reanalysis model suggests that this increase in free tropospheric aerosol concentrations are due to the lifting of boundary layer pollutants through an increase in convection (and vertical velocity) in a changing climate. In contrast, a consistent decreasing trend is observed over China irrespective of the altitude. Interestingly, a decreasing trend in Aerosol Optical Depth is observed over the northwest India and we relate this to an observed increase in precipitation leading to increase in the vegetation. It is also found that long-term oscillations like QBO, ENSO and solar cycle significantly affect the aerosol concentrations. Thus, it is prudent to conclude that background meteorology and dynamics play an important role in changing patterns of aerosol vertical distribution.

In this work, the detailed changes in the structure, dynamics and trace gases within the Asian summer monsoon anticyclone (ASMA) during extreme El Niño of 2015–16 is delineated by using Aura Microwave Limb Sounder (MLS) measurements, COSMIC Radio Occultation (RO) temperature, and NCEP reanalysis products. We have considered the individual months of July and August 2015 for the present study. The results show that the ASMA structure was quite different in 2015 as compared to the long-term (2005–2014) mean. In July, the spatial extension of the ASMA shows larger than the long-term mean in all the regions except over northeastern Asia, where, it exhibits a strong southward shift in its position. The ASMA splits into two and western Pacific mode is evident in August. Interestingly, the subtropical westerly jet (STJ) shifted southward from its normal position over northeastern Asia as resulted mid latitude air moved southward in 2015. Intense Rossby wave breaking events along with STJ are also found in July 2015. Due to these dynamical changes in the ASMA, pronounced changes in the ASMA tracers are noticed in 2015 compared to the long-term mean. A 30 % (20 %) decrease in carbon monoxide (water vapor) at 100 hPa is observed in July over most of the ASMA region, whereas in August the drop is strongly concentrated in the edges of the ASMA. Prominent increase of O3 (> 40 %) at 100 hPa is clearly evident within the ASMA in July, whereas in August the increase is strongly located (even at 121 hPa) over the western edges of the ASMA. Further, the temperature around the tropopause shows significant positive anomalies (~ 5 K) within the ASMA in 2015. Overall, warming of the tropopause region due to the increased O3 weakens the anticyclone and further supported the weaker ASMA in 2015 reported by previous studies.

In the present scenario, the development of eco-friendly multifunctional biocidal substances with low cost and high efficiency, has become the center of focus. This study is, focused on the synthesis of magnesium oxide (MgO) and chitosan-modified magnesium oxide (CMgO) nanoparticles (NPs), via a green precipitation process. In this process, leaves extract of Plumbago zeylanica L was, used as a nucleating agent. The MgO and CMgO NPs exhibit face-centered cubic structures, as confirmed by XRD studies. Morphologically, the FESEM and TEM images showed that the MgO and CMgO NPs were spherical, with an average particle size of ~40 ± 2 and ~37 ± 2 nm, respectively. EDX spectra were used to identify the elemental compositions of the nanoparticles. By using FTIR spectra, the Mg-O stretching frequency of MgO and CMgO NPs were observed at 431 and 435 cm–1, respectively. The photoluminescence (PL) spectra of MgO and CMgO NPs, revealed oxygen vacancies at 499 nm and 519 nm, respectively, due to the active radicals generated, which were responsible for their biocidal activities. The toxicity effects of the nanoparticles developed, on cell viability (antibacterial and anticancer), were measured on the MCF-7 cell line and six different types of gram-negative bacteria. The antibacterial activities of the nanoparticles on: Klebsiella pneumoniae, Escherichia coli, Shigella dysenteriae, Pseudomonas aeruginosa, Proteus vulgaris and Vibrio cholerae bacteria, were studied with the well diffusion method. The MgO and CMgO NPs were tested on breast cancer cell line (MCF-7) via an MTT assay and it proved that CMgO NPs possess higher anticancer properties than MgO NPs. Overall, CMgO NPs showed a higher amount of cytotoxicity for both the bacterial and cancer cells when compared to the MgO NPs. Toxicity studies of fibroblast L929 cells revealed that the CMgO NPs were less harmful to the healthy cells when compared to the MgO NPs. These results suggest that biopolymer chitosan-modified MgO NPs can be used for healthcare industrial applications in order to improve human health conditions.

We explain various aspects related to lightning occurrence frequency and intensity over the Indian region. Lightning frequency and magnitude are found to be larger in the east coast and adjoining regions. Atmospheric instability and aerosol concentrations appear to be the dominant factor affecting lightning occurrences while moisture content modulates the lightning intensity. A mechanism has been devised to explain how enhanced global warming can lead to taller and thicker clouds reaching up to the upper troposphere lower stratosphere region thereby leading to stronger and more lightning activities. Finally this hypothesis has been utilized to understand the futuristic scenarios of lightning over the Indian region using global model simulations.

The Indian Space Research Organization (ISRO), in collaboration with Centre National d’Etudes Spatiales, France, launched radio occultation sounder for atmosphere (ROSA) on-board Megha Tropiques (M...

Cloud vertical structure, including top and base altitudes, thickness of cloud layers, and the vertical distribution of multilayer clouds, affects large-scale atmosphere circulation by altering gradients in the total diabatic heating and cooling and latent heat release. In this study, long-term (11 years) observations of high-vertical-resolution radiosondes are used to obtain the cloud vertical structure over a tropical station at Gadanki (13.5° N, 79.2° E), India. The detected cloud layers are verified with independent observations using cloud particle sensor (CPS) sonde launched from the same station. High-level clouds account for 69.05 %, 58.49 %, 55.5 %, and 58.6 % of all clouds during the pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. The average cloud base (cloud top) altitudes for low-level, middle-level, high-level, and deep convective clouds are 1.74 km (3.16 km), 3.59 km (5.55 km), 8.79 km (10.49 km), and 1.22 km (11.45 km), respectively. Single-layer, two-layer, and three-layer clouds account for 40.80 %, 30.71 %, and 19.68 % of all cloud configurations, respectively. Multilayer clouds occurred more frequently during the monsoon with 34.58 %. Maximum cloud top altitude and cloud thickness occurred during the monsoon season for single-layer clouds and the uppermost layer of multiple-layer cloud configurations. In multilayer cloud configurations, diurnal variations in the thickness of upper-layer clouds are larger than those of lower-layer clouds. Heating and cooling in the troposphere and lower stratosphere due to these cloud layers are also investigated and peak cooling (peak warming) is found below (above) the cold-point tropopause (CPT) altitude. The magnitude of cooling (warming) increases from single-layer to four- or more-layer cloud occurrence. Further, the vertical structure of clouds is also studied with respect to the arrival date of the Indian summer monsoon over Gadanki.

Rubia cordifolia L., is an industrially viable medicinal crop and is widely exploited for the therapeutic potential of its bioactive metabolite, purpurin. The present investigation aimed to explore the chemotypic and molecular variability in seven wild populations of R. cordifolia from South Eastern Ghats region of India. Thirty-eight individuals were assessed for molecular fingerprinting (ISSR markers) and densitometric quantification of purpurin and alizarin. The populations of Yelagiri Hills and Shervaroy Hills contained the highest levels of alizarin (0.115 and 0.093%, respectively) while Pachamalai and Kolli Hills revealed the highest purpurin content (0.284 and 0.280%, respectively). Genetic diversity was generally higher in the same populations that produced higher metabolite content, with the exception of Pachamalai, suggesting a highly prioritized conservation concern. The study revealed a Nei's total gene diversity at species level of 0.266 and of 0.187 at population level, with an average population genetic differentiation of 0.28. No clear genetic or chemical structure was retrieved between the studied populations, with individuals from different locations clustering together, and no significant correlation was obtained between metabolites and genetic diversity or between these and the populations' geographic distances.