scholarly journals Intensification of Tropical Cyclone FANI Observed by INSAT-3DR Rapid Scan Data

2021 ◽  
Author(s):  
Neeru Jaiswal ◽  
Sanjib K. Deb ◽  
Chandra M. Kishtawal
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Inner Core ◽  
Operation Mode ◽  
Radial Distance ◽  
Extreme Weather Events ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Rapid Scan ◽  
Scan Data

Abstract Geo-stationary satellite images are one of the primary tool for real-time monitoring and intensity analysis of Tropical Cyclones (TCs) in spite of other complimentary remote sensing sensors like scatterometers, microwave imagers and sounders, mounted on the polar orbiting satellites. The weather activities over Indian region are continuously monitored by two Indian geostationary satellites viz., INSAT-3D and INSAT-3DR for every 15 minutes in staggered mode. During extreme weather events like TCs, INSAT-3DR is operated in rapid scan operation mode by taking observations over the system in every 4-minutes interval. These observations are highly useful in understating the instantaneous structural changes during evolution, intensification and landfall of TC. The salient observations over the cloud systems by visible, thermal infrared (TIR1), and water vapour imageries of INSAT-3DR satellite during the life cycle of the TC FANI are presented in this paper. The rapidly evolving small-scale features inside the inner core of TC FANI in high temporal resolution images were examined. The large-scale circulation features are analysed by atmospheric motion winds generated using rapid scan infrared images of INSAT-3DR. The relationship between TC intensity and inner core TIR1 BT, number of overshooting top clouds in the differenced TIR1-WV BT have been presented by analysing the sequence of INSAT-3DR imageries. The strong correlation (r2=0.74) was obtained between the TC eye temperature and radial distance of first overshooting cloud top. The 1 km x 1 km visible images of TC were found to have the presence of small-scale mesovortices in the eye region, which are a typical characteristic of intense TC system. The rapid scan operation mode generated sequence of images have been presented to show their application to identify the signatures of TC intensification.

scholarly journals Post-rendezvous radar properties of comet 67P/CG from the Rosetta Mission: understanding future Earth-based radar observations and the dynamical evolution of comets

2019 ◽  
Vol 489 (2) ◽  
pp. 1667-1683 ◽  
Author(s):  
Essam Heggy ◽  
Elizabeth M Palmer ◽  
Alain Hérique ◽  
Wlodek Kofman ◽  
M Ramy El-Maarry
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Dynamical Evolution ◽  
Textural Properties ◽  
Building Blocks ◽  
Cometary Nucleus ◽  
Small Scale ◽  
Small Bodies ◽  
Radar Observations ◽  
Comet 67P

ABSTRACT Radar observations provide crucial insights into the formation and dynamical evolution of comets. This ability is constrained by our knowledge of the dielectric and textural properties of these small-bodies. Using several observations by Rosetta as well as results from the Earth-based Arecibo radio telescope, we provide an updated and comprehensive dielectric and roughness description of Comet 67P/CG, which can provide new constraints on the radar properties of other nuclei. Furthermore, contrary to previous assumptions of cometary surfaces being dielectrically homogeneous and smooth, we find that cometary surfaces are dielectrically heterogeneous ( εr′≈1.6–3.2), and are rough at X- and S-band frequencies, which are widely used in characterization of small-bodies. We also investigate the lack of signal broadening in CONSERT observations through the comet head. Our results suggest that primordial building blocks in the subsurface are either absent, smaller than the radar wavelength, or have a weak dielectric contrast (Δ εr′). To constrain this ambiguity, we use optical albedo measurements by the OSIRIS camera of the freshly exposed subsurface after the Aswan cliff collapse. We find that the hypothetical subsurface blocks should have |Δ εr′|≳0.15, setting an upper limit of ∼ 1 m on the size of 67P/CG's primordial building blocks if they exist. Our analysis is consistent with a purely thermal origin for the ∼ 3 m surface bumps on pit walls and cliff-faces, hypothesized to be high-centred polygons formed from fracturing of the sintered shallow ice-bearing subsurface due to seasonal thermal expansion and contraction. Potential changes in 67P/CG's radar reflectivity at these at X- and S-bands can be associated with large-scale structural changes of the nucleus rather than small-scale textural ones. Monitoring changes in 67P/CG's radar properties during repeated close-approaches via Earth-based observations can constrain the dynamical evolution of its cometary nucleus.

scholarly journals Limitations of using a thermal imager for snow pit temperatures

2014 ◽  
Vol 8 (2) ◽  
pp. 387-394 ◽  
Author(s):  
M. Schirmer ◽  
B. Jamieson
Keyword(s):  
Surface Structure ◽  
Large Scale ◽  
Structural Changes ◽  
Thermal Structure ◽  
Large Temperature ◽  
Small Scale ◽  
Thermal Imager ◽  
Snow Layer ◽  
Ir Camera ◽  
Near Surface

Abstract. Driven by temperature gradients, kinetic snow metamorphism plays an import role in avalanche formation. When gradients based on temperatures measured 10 cm apart appear to be insufficient for kinetic metamorphism, faceting close to a crust can be observed. Recent studies that visualised small-scale (< 10 cm) thermal structures in a profile of snow layers with an infrared (IR) camera produced interesting results. The studies found melt-freeze crusts to be warmer or cooler than the surrounding snow depending on the large-scale gradient direction. However, an important assumption within these studies was that a thermal photo of a freshly exposed snow pit was similar enough to the internal temperature of the snow. In this study, we tested this assumption by recording thermal videos during the exposure of the snow pit wall. In the first minute, the results showed increasing gradients with time, both at melt-freeze crusts and artificial surface structures such as shovel scours. Cutting through a crust with a cutting blade or shovel produced small concavities (holes) even when the objective was to cut a planar surface. Our findings suggest there is a surface structure dependency of the thermal image, which was only observed at times during a strong cooling/warming of the exposed pit wall. We were able to reproduce the hot-crust/cold-crust phenomenon and relate it entirely to surface structure in a temperature-controlled cold laboratory. Concave areas cooled or warmed more slowly compared with convex areas (bumps) when applying temperature differences between snow and air. This can be explained by increased radiative and/or turbulent energy transfer at convex areas. Thermal videos suggest that such processes influence the snow temperature within seconds. Our findings show the limitations of using a thermal camera for measuring pit-wall temperatures, particularly during windy conditions, clear skies and large temperature differences between air and snow. At crusts or other heterogeneities, we were unable to create a sufficiently planar snow pit surface and non-internal gradients appeared at the exposed surface. The immediate adjustment of snow pit temperature as it reacts with the atmosphere complicates the capture of the internal thermal structure of a snowpack with thermal videos. Instead, the shown structural dependency of the IR signal may be used to detect structural changes of snow caused by kinetic metamorphism. The IR signal can also be used to measure near surface temperatures in a homogenous new snow layer.

Numerical Simulation of Hurricane Bonnie (1998). Part II: Sensitivity to Varying Cloud Microphysical Processes

2006 ◽  
Vol 63 (1) ◽  
pp. 109-126 ◽  
Author(s):  
Tong Zhu ◽  
Da-Lin Zhang
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Inner Core ◽  
Cloud Microphysics ◽  
Cloud Water ◽  
Heat Of Fusion ◽  
Hurricane Intensity ◽  
Cloud Band ◽  
Intensity Changes ◽  
Hurricane Bonnie

Abstract In this study, the effects of various cloud microphysics processes on the hurricane intensity, precipitation, and inner-core structures are examined with a series of 5-day explicit simulations of Hurricane Bonnie (1998), using the results presented in Part I as a control run. It is found that varying cloud microphysics processes produces little sensitivity in hurricane track, except for very weak and shallow storms, but it produces pronounced departures in hurricane intensity and inner-core structures. Specifically, removing ice microphysics produces the weakest (15-hPa underdeepening) and shallowest storm with widespread cloud water but little rainwater in the upper troposphere. Removing graupel from the control run generates a weaker hurricane with a wider area of precipitation and more cloud coverage in the eyewall due to the enhanced horizontal advection of hydrometeors relative to the vertical fallouts (or increased water loading). Turning off the evaporation of cloud water and rainwater leads to the most rapid deepening storm (i.e., 90 hPa in 48 h) with the smallest radius but a wider eyewall and the strongest eyewall updrafts. The second strongest storm, but with the most amount of rainfall, is obtained when the melting effect is ignored. It is found that the cooling due to melting is more pronounced in the eyewall where more frozen hydrometeors, especially graupel, are available, whereas the evaporative cooling occurs more markedly when the storm environment is more unsaturated. It is shown that stronger storms tend to show more compact eyewalls with heavier precipitation and more symmetric structures in the warm-cored eye and in the eyewall. It is also shown that although the eyewall replacement scenarios occur as the simulated storms move into weak-sheared environments, the associated inner-core structural changes, timing, and location differ markedly, depending on the hurricane intensity. That is, the eyewall convection in weak storms tends to diminish shortly after being encircled by an outer rainband, whereas both the cloud band and the inner eyewall in strong storms tend to merge to form a new eyewall with a larger radius. The results indicate the importance of the Bergeron processes, including the growth and rapid fallout of graupel in the eyewall, and the latent heat of fusion in determining the intensity and inner-core structures of hurricanes, and the vulnerability of weak storms to the influence of large-scale sheared flows in terms of track, inner-core structures, and intensity changes.

scholarly journals Magnetic and velocity fields in a dynamo operating at extremely small Ekman and magnetic Prandtl numbers

2017 ◽  
Vol 47 (4) ◽  
pp. 261-276
Author(s):  
Ján Šimkanin ◽  
Juraj Kyselica
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Inner Core ◽  
Strong Field ◽  
Boussinesq Approximation ◽  
Velocity Fields ◽  
Small Scale ◽  
Prandtl Numbers ◽  
Core Rotation ◽  
Inner Core Rotation

AbstractNumerical simulations of the geodynamo are becoming more realistic because of advances in computer technology. Here, the geodynamo model is investigated numerically at the extremely low Ekman and magnetic Prandtl numbers using the PARODY dynamo code. These parameters are more realistic than those used in previous numerical studies of the geodynamo. Our model is based on the Boussinesq approximation and the temperature gradient between upper and lower boundaries is a source of convection. This study attempts to answer the question how realistic the geodynamo models are. Numerical results show that our dynamo belongs to the strong-field dynamos. The generated magnetic field is dipolar and large-scale while convection is small-scale and sheet-like flows (plumes) are preferred to a columnar convection. Scales of magnetic and velocity fields are separated, which enables hydromagnetic dynamos to maintain the magnetic field at the low magnetic Prandtl numbers. The inner core rotation rate is lower than that in previous geodynamo models. On the other hand, dimensional magnitudes of velocity and magnetic fields and those of the magnetic and viscous dissipation are larger than those expected in the Earth’s core due to our parameter range chosen.

scholarly journals The Dynamics of Vortex Rossby Waves and Secondary Eyewall Development in Hurricane Matthew (2016): New Insights from Radar Measurements

2020 ◽  
Vol 77 (7) ◽  
pp. 2349-2374 ◽  
Author(s):  
Stephen R. Guimond ◽  
Paul D. Reasor ◽  
Gerald M. Heymsfield ◽  
Matthew M. McLinden
Keyword(s):  
Angular Momentum ◽  
Large Scale ◽  
Rossby Waves ◽  
Inner Core ◽  
Small Scale ◽  
Wave Kinematics ◽  
Secondary Eyewall Formation ◽  
Radial Flux ◽  
Momentum Budget ◽  
Radar Measurements

AbstractThe structure of vortex Rossby waves (VRWs) and their role in the development of a secondary eyewall in Hurricane Matthew (2016) is examined from observations taken during the NOAA Sensing Hazards with Operational Unmanned Technology (SHOUT) field experiment. Radar measurements from ground-based and airborne systems, with a focus on the NASA High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) instrument on the Global Hawk aircraft, revealed the presence of ~12–15-km-wavelength spiral bands breaking from the inner-core eyewall in the downshear-right quadrant. The vorticity characteristics and calculations of the intrinsic phase speeds of the bands are shown to be consistent with sheared VRWs. A new angular momentum budget methodology is presented that allows an understanding of the secondary eyewall development process with narrow-swath radar measurements. Filtering of the governing equations enables explicit insight into the nonlinear dynamics of scale interactions and the role of the VRWs in the storm structure change. The results indicate that the large-scale (scales > 15 km) vertical flux convergence of angular momentum associated with the VRWs dominates the time tendency with smaller effects from the radial flux term. The small-scale (scales ≤ 15 km) vertical term produces weak, but nonnegligible nonlinear forcing of the large scales primarily through the Reynolds and cross-stress components. The projection of the wave kinematics onto the low-wavenumber (0 and 1) fields appears to be the more significant dynamic process. Flight-level observations show secondary peaks in tangential winds in the radial region where the VRW forcing signatures are active, connecting them with the secondary eyewall formation process.

Structural Change and Growth of Manufacturing Industries in Punjab: Post-Reforms Analysis

2020 ◽  
pp. 389-396
Keyword(s):  
Structural Change ◽  
Large Scale ◽  
Structural Changes ◽  
Manufacturing Sector ◽  
Small Scale ◽  
Rapid Decline ◽  
Optimum Level ◽  
Current Crisis ◽  
Employment Opportunities ◽  
Unskilled Labour

After the economic reforms of July 1991, the process of structural change led to jumping from the primary sector of the economy to tertiary by surpassing the secondary sector in India and Punjab in particular. Indeed, this process led to a rapid decline in the capacity of the manufacturing sector to offer jobs and the limited scope of the modern services sector to absorb relatively unskilled labour that was displaced from agriculture, which resulted in uneven growth of the economy, and increased unemployment. The study analysed these structural changes and its implications on the growth of production and employment of the manufacturing sector in Punjab. It was found that since the 1990s, the growth of manufacturing sector in Punjab was stagnant, whereas the trends in production and employment were declining. So, to achieve the optimum level of employment opportunities and mitigate the current crisis looming in the state of Punjab, there is a need to design a mechanism for encouraging investments in manufacturing sector particularly, in small scale industries as these industries have a greater advantage over medium/large scale units, because it uses local inputs, creates more employment opportunities and needs less start-up capital than the latter.

H2020 'PHUSICOS': Nature-based solutions to reduce hydro-meteorological risk in rural mountain areas

2020 ◽  
Author(s):  
Anders Solheim ◽  
Amy Oen ◽  
Bjørn Kalsnes ◽  
Vittoria Capobianco
Keyword(s):  
Large Scale ◽  
Economic Benefits ◽  
Rock Fall ◽  
Limiting Factors ◽  
Extreme Weather Events ◽  
Small Scale ◽  
Mountain Areas ◽  
Mountainous Regions ◽  
Living Lab ◽  
Starting Point

&lt;p&gt;Nature-based solutions (NBS) are &quot;inspired and supported by nature. They are cost-effective and simultaneously provide environmental, social and economic benefits and help build resilience&quot; (EU, 2015). The main objective of the H2020 project PHUSICOS is to demonstrate the implementation of nature-based solutions to reduce the risk of extreme weather events in vulnerable areas such as rural mountain landscapes. To meet this aim, three large-scale demonstration sites have been selected in Tuscany, Italy, The Pyrenees, France/Spain and the Gudbrandsdalen Valley, Norway as representative of hydro-meteorological hazards, vegetation, topography and infrastructure throughout rural and mountainous regions in Europe. Additionally, two small-scale concept cases are established in Kaunertal Valley, Austria and the Isar River Basin, Germany to test specific challenges. This presentation focuses on the three large scale demonstrator sites.&lt;/p&gt;&lt;p&gt;PHUSICOS started in 2018 and over the four-year period each demonstrator site shall propose and implement at least three NBS projects each. At present 9 NBSs have been proposed.&lt;/p&gt;&lt;p&gt;The Italian proposals, organized by Autorit&amp;#224; di Bacino Distrettuale, ADBS, relate to the pollution, drought, erosion, and land degradation around lake Massaciuccoli in Tuscany. The measures are related to reduce the runoff from farmland to the channels and the lake, as well as to reduce the high salinity of the lake. Proposed measures include feeding water from the Serchio River to the lake, and the establishment of vegetation buffer strips between the farmed land and the channels and retention basins.&lt;/p&gt;&lt;p&gt;In the Pyrenees, the proposed measures, organized by Consorcio de la Comunidad de Trabajo de los Pirineos, CTP, are to reduce risk from several hydrometeorological hazards; flooding and torrents, erosion, snow avalanches and rock fall. The measures include afforestation to reduce snow avalanche release, modification of river banks and beds to reduce torrent hazard, revegetation to reduce erosive rock fall from till deposits, and the use of local wood to prevent release of rock fall as well as forest management to reduce block velocity and runout.&lt;/p&gt;&lt;p&gt;The Norwegian NBS proposal, organized by Oppland County Administration, is to reduce flooding, erosion, and problematic redeposition in a confluence zone between a tributary and the main river. The measure is a green, receded barrier, to provide flooding space for the river and secure adequate conditions for the riparian vegetation and several red-list species.&lt;/p&gt;&lt;p&gt;PHUSICOS aims to involve stakeholders in Living Lab processes at the demonstration sites and has succeeded to different degrees depending on the starting point of the NBSs towards their implementation. Baseline surveys of key monitoring parameters are also being performed for selected measures at the three sites.&lt;/p&gt;&lt;p&gt;The main challenges include getting the most representative stakeholders involved in the Living Lab process, and, perhaps most important, adhering to the local laws and regulations, including environmental and tendering processes. These local regulations are already delaying the progress towards implementation of the measures within the time frame of PHUSICOS. The presentation will elaborate on the selected NBS, their co-benefits and on the challenges, which may be limiting factors for such projects.&lt;/p&gt;

scholarly journals Monitoring the Jet in Centaurus A at 0.1 Parsec Resolution

1996 ◽  
Vol 175 ◽  
pp. 21-22
Author(s):  
R.A. Preston ◽  
S.J. Tingay ◽  
D.L. Jauncey ◽  
J.E. Reynolds ◽  
J.E.J. Lovell ◽  
...  
Keyword(s):  
Radio Source ◽  
Large Scale ◽  
Structural Changes ◽  
Elliptical Galaxy ◽  
Structural Evolution ◽  
Small Scale ◽  
Extragalactic Radio Source ◽  
Dual Frequency ◽  
Complex Structural ◽  
Centaurus A

Centaurus A is the closest active extragalactic radio source, at a distance of approximately 3.5 Mpc, and is identified with the peculiar elliptical galaxy NGC 5128. As such it is a very important target for observations of the small-scale (sub-parsec) and large-scale (kpc) structures in extragalactic jets. Here we present Mk-II VLBI observations made at 8.4 GHz over a 4.3 year period from early 1991 until mid-1995, as well as a 4.8 GHz observation that was co-eval with one of the 8.4 GHz observations. All of the observations were made with the SHEVE array except for the last observation which was made with the VLBA. The dual-frequency observations identify the core of the radio source, while the multi-epoch observations show the complex structural evolution at a resolution of 0.1 pc. Subluminal motion of ≈ 0.15c is evident. Structural changes are observed on time scales shorter than four months.

scholarly journals Limitations of using a thermal imager for snow pit temperatures

2013 ◽  
Vol 7 (5) ◽  
pp. 5231-5253
Author(s):  
M. Schirmer ◽  
B. Jamieson
Keyword(s):  
Surface Structure ◽  
Large Scale ◽  
Structural Changes ◽  
Thermal Structure ◽  
Large Temperature ◽  
Small Scale ◽  
Thermal Imager ◽  
Snow Layer ◽  
Ir Camera ◽  
Near Surface

Abstract. Driven by temperature gradients, kinetic snow metamorphism is important for avalanche formation. Even when gradients appear to be insufficient for kinetic metamorphism, based on temperatures measured 10 cm apart, faceting close to a~crust can still be observed. Recent studies that visualized small scale (< 10 cm) thermal structures in a profile of snow layers with an infrared (IR) camera produced interesting results. The studies found melt-freeze crusts to be warmer or cooler than the surrounding snow depending on the large scale gradient direction. However, an important assumption within the studies was that a thermal photo of a freshly exposed snow pit was similar enough to the internal temperature of the snow. In this study, we tested this assumption by recording thermal videos during the exposure of the snow pit wall. In the first minute, the results showed increasing gradients with time, both at melt-freeze crusts and at artificial surface structures such as shovel scours. Cutting through a crust with a cutting blade or a shovel produced small concavities (holes) even when the objective was to cut a planar surface. Our findings suggest there is a surface structure dependency of the thermal image, which is only observed at times with large temperature differences between air and snow. We were able to reproduce the hot-crust/cold-crust phenomenon and relate it entirely to surface structure in a temperature-controlled cold laboratory. Concave areas cooled or warmed slower compared with convex areas (bumps) when applying temperature differences between snow and air. This can be explained by increased radiative transfer or convection by air at convex areas. Thermal videos suggest that such processes influence the snow temperature within seconds. Our findings show the limitations of the use of a thermal camera for measuring pit-wall temperatures, particularly in scenarios where large gradients exist between air and snow and the interaction of snow pit and atmospheric temperatures are enhanced. At crusts or other heterogeneities, we were unable to create a sufficiently homogenous snow pit surface and non-internal gradients appeared at the exposed surface. The immediate adjustment of snow pit temperature as it reacts with the atmosphere complicates the capture of the internal thermal structure of a snowpack even with thermal videos. Instead, the shown structural dependency of the IR signal may be used to detect structural changes of snow caused by kinetic metamorphism. The IR signal can also be used to measure near surface temperatures in a homogenous new snow layer.

Farmers' experiments in Cuba

2012 ◽  
Vol 29 (1) ◽  
pp. 48-64 ◽  
Author(s):  
Friedrich Leitgeb ◽  
Susanne Kummer ◽  
Fernando R. Funes-Monzote ◽  
Christian R. Vogl
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Plant Protection ◽  
Participant Observation ◽  
Transition Process ◽  
Resource Scarcity ◽  
Plant Production ◽  
Small Scale ◽  
Structured Interviews ◽  
External Resources

AbstractDue to the collapse of the socialist systems in 1989, Cuba's government promoted a series of structural changes to deal with resource scarcity and to enhance agricultural productivity. The upcoming crisis triggered adaptation strategies and led to a large-scale transition process towards a more sustainable model of agriculture. Farmers' experiments have been an implicit part of this process. Nowadays, farmers' capacity to experiment is widely accepted among the scientific community. However, detailed descriptions of farmers' approaches to experimentation are scarce. In this study, we examine the topics, resources, sources, motives, methods and outcomes of farmers' experiments in Cuba. The research methods comprised semi-structured interviews with 72 Cuban farmers, field notes, participant observation and a research diary. Key informants and 34 expert interviews added important insights into analysis. The results reveal that farmers' experiments are an integral part of farming in Cuba. Most farmers reported realizing their own experiments on their farms. The use of locally available resources was a crucial element for farmers' experiments. The topics were related to the introduction of new plant species or varieties, plant production, mechanization, fertilization, plant protection and the introduction of new animal species. The farmers' own idea was the most important source for experimenting, followed by ideas offered by colleagues and family members. Increasing production, independence from external resources and improving farm management were the main motives for experimenting. More than half of the farmers started to experiment without detailed written or mental planning, but made some considerations about the experiment before starting. Some planned more in detail and a few farmers devised a written plan, draft or model. Starting on a small scale was a way to minimize risks. The experiments were mainly evaluated by observation and comparison. Only a few farmers took records of their experiments. The most important outcomes were higher production, food self-sufficiency, work easement, improved plant health, increased knowledge, higher working efficiency and better taste of products. Farmers' experiments are a means of learning and they enhance farmers' capacity to adapt to changing conditions.

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