148 research outputs found
Traditional Uses of Some Medicinal Plants by tribals of Gangaraju Madugula Mandal of Visakhapatnam District, Andhra Pradesh
During the years 2007-2008 several field trips were conducted to document the ethnomedicinal remedies for 47 diseases with 90 plant species of Angiosperms from three major tribes viz: Bagatas, Konda Doras and Valmikis who have been residing in Gangaraju Madugula Mandal of Visakhapatnam district. The plants were deposited as herbarium specimens in Andhra University, Visakhapatnam, India
Historical and Projected Surface Temperature over India during the 20th and 21st century.
Surface Temperature (ST) over India has increased by ~0.055 K/decade during 1860-2005 and follows the global warming trend. Here, the natural and external forcings (e.g., natural and anthropogenic) responsible for ST variability are studied from Coupled Model Inter-comparison phase 5 (CMIP5) models during the 20th century and projections during the 21st century along with seasonal variability. Greenhouse Gases (GHG) and Land Use (LU) are the major factors that gave rise to warming during the 20th century. Anthropogenic Aerosols (AA) have slowed down the warming rate. The CMIP5 projection over India shows a sharp increase in ST under Representative Concentration Pathways (RCP) 8.5 where it reaches a maximum of 5 K by the end of the 21st century. Under RCP2.6 emission scenarios, ST increases up to the year 2050 and decreases afterwards. The seasonal variability of ST during the 21st century shows significant increase during summer. Analysis of rare heat and cold events for 2080-2099 relative to a base period of 1986-2006 under RCP8.5 scenarios reveals that both are likely to increase substantially. However, by controlling the regional AA and LU change in India, a reduction in further warming over India region might be achieved
Activity of radon (222Rn) in the lower atmospheric surface layer of a typical rural site in south India
Analysis of one year measurements of in situ radon (222Rn) and its progenies along with surface air temperature, relative humidity and pressure near to the Earth’s surface has been carried out for the first time at the National Atmospheric Research Laboratory (NARL, 13.5∘N and 79.2∘E) located in a rural site in Gadanki, south India. The dataset was analysed to understand the behaviour of radon in relation to the surface air temperature and relative humidity at a rural site. It was observed that over a period of the 24 hours in a day, the activity of radon and its progenies reaches a peak in the morning hours followed by a remarkable decrease in the afternoon hours. Relatively, a higher concentration of radon was observed at NARL during fair weather days, and this can be attributed to the presence of rocky hills and dense vegetation surrounding the site. The high negative correlation between surface air temperature and activity of radon (R = – 0.70, on an annual scale) suggests that dynamical removal of radon due to increased vertical mixing is one of the most important controlling processes of the radon accumulation in the atmospheric surface layer. The annual averaged activity of radon was found to be 12.01±0.66 Bq m−3 and 4.25±0.18 Bq m−3 for its progenies, in the study period
Long-term trends of instability and associated parameters over the Indian region obtained using a radiosonde network
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.</p
Assessment of GPS radiosonde descent data
Radiosondes are widely used to obtain basic meteorological parameters such
as pressure (<i>P</i>), temperature (<i>T</i>), relative humidity (RH) and horizontal
winds during the balloon ascent up to the altitude of balloon burst, usually
~ 32–35 km. Data from the radiosondes released from Gadanki
(13.5° N, 79.2° E), a tropical station in India, have been collected
during the ascent and during the descent as well without attaching any
parachute or its equivalent since the year 2008. In the present study an
attempt has been made to characterize the radiosonde descent data with the
main objective of exploring its usefulness and reliability for scientific
purposes. We compared the data obtained during ascent and descent phases of
the same sounding. The mean differences in <i>T</i>, RH and horizontal winds
between ascent and descent data are found to be small and are sometimes even
within the uncertainty of the measurements and/or expected diurnal variation
itself. The very good consistency observed between the ascent and the
descent data shows that one more profile of the meteorological parameters
can be constructed within 3 h of time of balloon launch practically at no
additional cost. Further checks are done by utilizing the 3-hourly
radiosonde observations collected during the Tropical Tropopause Dynamics
campaigns conducted at Gadanki. In the process of checking the consistency
between the radiosonde ascent and descent data, several new findings are
arrived at and are reported in this study. In general, it has taken more
than half an hour for the balloon to reach the ground from the burst
altitude. It is also observed that the fall velocity is close to 10 m s<sup>−1</sup> near
the surface. Finally, it is suggested to record the observations also when
the balloon is descending as this information is useful for scientific
purposes
Cloud vertical structure over a tropical station obtained using long-term high-resolution radiosonde measurements
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.</p
Cognitive impairment prediction in patients with hypertension with Pulse Wave Velocity and arterial stiffness measurement
INTRODUCTION The blood supply of the brain gradually reduces with ongoing age, the cerebral cortex undergoes atrophy, causes cognitive inhibition converting to vascular dementia and Alzheimer’s
in later stages. The relation between cognitive impairment (CI) and high blood pressure has been long studied in elderly patients, necessitating for further research and evidence on this topic. AIM To study the parameters of arterial stiffness (AS): central blood pressure (CBP), pulse wave velocity (PWV) in patients with hypertension and determine it’s relationship with vascular CI. METHODS AND MATERIALS A systematic literature review was performed using a standardised
published methodology; 25 studies were selected from last 10 years from google search engine, Pubmed central and NCBI with keywords like AS, CBP, PWV, CI. RESULTS PWV was a significant and independently associated with cognitive function when measured with mini mental state examination in an elderly population in Japan. The relationship between high vascular stiffness and CI is explained as the disturbance in regulation of endothelial nitric oxide release. This in turn causes a neuronal energy crisis initiated by cerebral hypoperfusion due to impaired vascular tone and develops CI. As elderly population tend to have an increased risk for arteriosclerosis which is highly predicted by PWV, these patients are highly prone to develop vascular dementia and Alzheimer’s in future. CONCLUSION An inverse relation between AS and cognitive function was found and provided an evidence to vascular hypothesis of vascular dementia and Alzheimer’s. Prospective studies involving these early predictive markers PWV and AS may help in therapeutic intervention and progression of the disease
Studies on atmospheric gravity wave activity in the troposphere and lower stratosphere over a tropical station at Gadanki
MST radars are powerful tools to study the mesosphere, stratosphere and troposphere and have made considerable contributions to the studies of the dynamics of the upper, middle and lower atmosphere. Atmospheric gravity waves play a significant role in controlling middle and upper atmospheric dynamics. To date, frontal systems, convection, wind shear and topography have been thought to be the sources of gravity waves in the troposphere. All these studies pointed out that it is very essential to understand the generation, propagation and climatology of gravity waves. In this regard, several campaigns using Indian MST Radar observations have been carried out to explore the gravity wave activity over Gadanki in the troposphere and the lower stratosphere. The signatures of the gravity waves in the wind fields have been studied in four seasons viz., summer, monsoon, post-monsoon and winter. The large wind fluctuations were more prominent above 10 km during the summer and monsoon seasons. The wave periods are ranging from 10 min-175 min. The power spectral densities of gravity waves are found to be maximum in the stratospheric region. The vertical wavelength and the propagation direction of gravity waves were determined using hodograph analysis. The results show both down ward and upward propagating waves with a maximum vertical wave length of 3.3 km. The gravity wave associated momentum fluxes show that long period gravity waves carry more momentum flux than the short period waves and this is presented
Macro-physical, optical and radiative properties of tropical cirrus clouds and its temperature dependence at Gadanki (13.5° N, 79.2° E) observed by ground based lidar
The macro-physical and optical properties of cirrus clouds and its temperature dependencies have been investigated at the National Atmospheric Research Laboratory (NARL; 13.5° N, 79.2° E), Gadanki, Andhra Pradesh, India; an inland tropical station during the period of observation January to December 2009 using a ground based pulsed monostatic lidar system data and radiosonde measurements. Based on the analysis of measurements the cirrus macrophysical properties such as occurrence height, mid cloud temperature, cloud geometrical thickness, and optical properties such as extinction coefficient, optical depth, depolarization ratio and lidar ratio have been determined. The variation of cirrus macrophysical and optical properties with mid cloud temperature have also been studied. The cirrus clouds mean height has been generally observed in the range of 9-17 km with a peak occurrence at 13-14 km. The cirrus mid cloud temperatures were in the range from -81 °C to -46 °C. The cirrus geometrical thickness ranges from 0.9-4.5 km and 56% of cirrus occurrences have thickness 1.0 -2.7 km. The monthly cirrus optical depth ranges from 0.01-0.47, but most (>80%) of the cirrus have values less than 0.1. The monthly mean cirrus extinction ranges from 2.8E-06 to 8E-05 and depolarization ratio and lidar ratio varies from 0.13 to 0.77 and 2 to 52 respectively. The temperature and thickness dependencies on cirrus optical properties have also been studied. A maximum cirrus geometrical thickness of 4.5 km is found at temperatures around – 46 °C with an indication that optical depth increases with increasing thickness and mid cloud temperature. The cloud radiative properties such as outgoing long-wave radiation (OLR) flux and cirrus IR forcing are studied. OLR flux during the cirrus occurrence days ranged from 348-456 W/m2 with a low value in the monsoon period. The cirrus IR forcing varied from 3.13 – 110.54 W/m2 and shows a peak at monsoon period
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