Near real time plasma irregularity monitoring by FORMOSAT-7/COSMIC-2

2020 ◽  
Author(s):  
ShihPing Chen ◽  
Charles C. Lin ◽  
Rajesh Panthalingal Krishnanunni ◽  
Richard Eastes ◽  
Jong-Min Choi
Keyword(s):  
Real Time ◽  
Global Scale ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Plasma Irregularities ◽  
Ion Drift ◽  
F Region ◽  
Low Latitudes ◽  
Bottom Side

<p>The near real-time global plasma bubble map is constructed by utilizing the FORMOSAT-7/COSMIC-2(F7/C2) radio occultation(RO) scintillation observations in low latitudes. Several tools investigating plasma bubbles like the rate of TEC index(ROTI), Range-Time-Intensity(RTI) diagrams of the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere(JULIA), and the Global-scale Observations of the Limb and Disk(GOLD) 135.6nm airglow observations are provided validating the RO scintillations. Result shows that the F7/C2 scintillation is sensitive detecting plasma irregularities, especially for the bottom side of these bubbles, which can be used to investigating nighttime vertical plasma drifts in low latitudinal F-region. The hourly quick look of the low latitude plasma bubble occurrence and vertical ion drift around the globe is significant to the space weather monitoring.</p>

scholarly journals Study of Equatorial Plasma Bubbles Using ASI and GPS Systems

2020 ◽  
Author(s):  
Dada P. Nade ◽  
Swapnil S. Potdar ◽  
Rani P. Pawar
Keyword(s):  
Electron Content ◽  
Gps Receiver ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Total Electron ◽  
Plasma Irregularities ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Background Density

The plasma irregularities have been frequently observed in the F-region, at low latitude regions, due to the instability processes occurring in the ionosphere. The depletions in electron density, as compared to the background density, is a signature of the plasma irregularities. These irregularities are also known as the “equatorial plasma bubble” (EPB). These EPBs can measure by the total electron content (TEC) using GPS receiver and by images of the nightglow OI 630.0 nm emissions using all sky imager (ASI). The current chapter is based on the review on the signature of the EPBs in TEC and ASI. measurements. We have also discussed the importance of the study of EPBs.

Characteristic of daytime F-region backscatter plume structures over low latitude of China

2021 ◽  
Author(s):  
Haiyong Xie
Keyword(s):  
Plasma Bubble ◽  
Low Latitude ◽  
Previous Night ◽  
Vhf Radar ◽  
F Region ◽  
Low Latitudes ◽  
June Solstice ◽  
Basic Characteristics ◽  
Maximum Occurrence

<p>Ionospheric F‐region irregularity backscatter plumes are commonly regarded as a nighttime phenomenon at equatorial and low latitudes. At daytime, there are very few reported cases of F‐region backscatter echoes. It is still not clear what caused the daytime echoes. In order to understand the occurrence of daytime F‐region echoes, we carried out an experiment with Sanya VHF radar (18.4°N, 109.6°E, dip lat. 12.8°N) during November 2016 to August 2020. Some basic characteristics were released: (1) The daytime F‐region echoing structures have an unexpected high occurrence in June solstice of solar minimum. (2) The echoing structures could appear at any time during 0700–1800 LT, with a maximum occurrence around 0900 LT. (3) The echoing structures appeared mostly above 350 km altitude, extending up to 650 km or more (F region topside) with apparent westward drifts at times. Radar interferometry and ICON satellite in situ results show that the daytime F‐region echoes were from plume structures consisting of field‐aligned irregularities. It is suggested that the plume structures could be remnants of equatorial plasma bubble (EPB) irregularities generated on the previous night around 100–125°E. They rise to high altitudes and drift zonally together with background plasma, causing the daytime F‐region backscattering structure over Sanya. With simultaneous observations of several VHF radars at different locations, satellite in-situ measurements and/or EPB model, the dynamics of daytime F-region backscatter plume structures could be better understood in the future.</p>

Research Progresses of Ionospheric Plasma Irregularities from the Ground–Based Airglow Network in China

2021 ◽  
Author(s):  
Jiyao Xu ◽  
Wei Yuan ◽  
Kun Wu ◽  
Longchang Sun
Keyword(s):  
Ionospheric Plasma ◽  
Ionospheric Disturbance ◽  
Geomagnetic Latitude ◽  
Extreme Weather Events ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Plasma Irregularities ◽  
Middle Latitudes ◽  
Weather Events ◽  
New Phenomena

<p>China, from north to south, spans from the middle latitudes to the low latitude both in geographic latitude and geomagnetic latitude. And China has a variety of topography environment, which including high lands, plains, seas, and long coasts. To better understand topographic and latitudinal effects on the mesosphere and thermosphere and features of ionospheric plasma irregularities at various latitudes in China, we have established a ground-based airglow network in China gradually since 2010, which consists of 16 stations. This network almost cover China, which focuses on two airglow layers: the OI (~250 km) and OH (~87 km) airglow layers. The observations from OI airglow layers provide convenience to systematically investigate the morphologic feature and evolution of ionospheric plasma irregularities over China. Based on the airglow network observations, we mainly report some important research results of ionospheric plasma irregularities in recent years. These findings include (1) statistical characteristic of equatorial plasma bubble (EPB) over China, (2) the influences of severe extreme weather events on the ionosphere, (3) interaction between medium-scale traveling ionospheric disturbance (MSTIDs) and ionospheric irregularity, and (4) some new phenomena of ionospheric irregularities.</p>

scholarly journals Analysing the Relationship between Multiple-Timescale SPI and GRACE Terrestrial Water Storage in the Framework of Drought Monitoring

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1672 ◽  
Author(s):  
Carmelo Cammalleri ◽  
Paulo Barbosa ◽  
Jürgen V. Vogt
Keyword(s):  
Real Time ◽  
Extreme Values ◽  
Water Storage ◽  
Global Scale ◽  
Drought Monitoring ◽  
Limited Area ◽  
Standardised Precipitation Index ◽  
Wide Range ◽  
Multiple Timescale

The operational monitoring of long-term hydrological droughts is often based on the standardised precipitation index (SPI) for long accumulation periods (i.e., 12 months or longer) as a proxy indicator. This is mainly due to the current lack of near-real-time observations of relevant hydrological quantities, such as groundwater levels or total water storage (TWS). In this study, the correlation between multiple-timescale SPIs (between 1 and 48 months) and GRACE-derived TWS is investigated, with the goals of: (i) evaluating the benefit of including TWS data in a drought monitoring system, and (ii) testing the potential use of SPI as a robust proxy for TWS in the absence of near-real-time measurements of the latter. The main outcomes of this study highlight the good correlation between TWS anomalies (TWSA) and long-term SPI (12, 24 and 48 months), with SPI-12 representing a global-average optimal solution (R = 0.350 ± 0.250). Unfortunately, the spatial variability of the local-optimal SPI underlines the difficulty in reliably capturing the dynamics of TWSA using a single meteorological drought index, at least at the global scale. On the contrary, over a limited area, such as Europe, the SPI-12 is able to capture most of the key traits of TWSA that are relevant for drought studies, including the occurrence of dry extreme values. In the absence of actual TWS observations, the SPI-12 seems to represent a good proxy of long-term hydrological drought over Europe, whereas the wide range of meteorological conditions and complex hydrological processes involved in the transformation of precipitation into TWS seems to limit the possibility of extending this result to the global scale.

scholarly journals Electrodynamics of the Low-latitude Thermosphere by Comparison of Zonal Neutral Winds and Equatorial Plasma Bubble Velocity

2015 ◽  
Vol 20 (2) ◽  
pp. 84-89 ◽  
Author(s):  
Narayan P. Chapagain
Keyword(s):  
Imaging System ◽  
Bubble Velocity ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Neutral Winds ◽  
Coupling Relationship ◽  
F Region ◽  
Fabry Perot ◽  
Optical Imaging System ◽  
Equatorial Plasma Bubble

The coincident observations of nighttime thermospheric zonal neutral winds and equatorial plasma bubble (EPB) drift velocities over Brazil during the October–December,2009 and 2010 are used to examine the coupling relationship between the thermosphere and ionosphere. The EPB zonal drift velocities are estimated using the airglow images recorded by optical imaging system, while the neutral winds are measured by using a bi-static Fabry–Perot interferometer (FPI) experiment deployed at two stations from Brazil. The results reveal the similar pattern in the EPB drift velocities and zonal neutral winds motion during the nighttime and night-to-night thereby illustrating a fully developed F-region dynamo. However, background natural winds also exceed EPBs velocities especially during the development phase of EPBs illustrating that F-region dynamo is not fully activated.Journal of Institute of Science and Technology, 2015, 20(2): 84-89  

scholarly journals Equatorial F-region plasma depletion drifts: latitudinal and seasonal variations

2003 ◽  
Vol 21 (12) ◽  
pp. 2315-2322 ◽  
Author(s):  
A. A. Pimenta ◽  
P. R. Fagundes ◽  
Y. Sahai ◽  
J. A. Bittencourt ◽  
J. R. Abalde
Keyword(s):  
Large Scale ◽  
Ionospheric Irregularities ◽  
Plasma Bubble ◽  
Plasma Irregularities ◽  
Optical Instruments ◽  
Plasma Bubbles ◽  
F Region ◽  
Variation Characteristics ◽  
Wind Velocities ◽  
Region Plasma

Abstract. The equatorial ionospheric irregularities have been observed in the past few years by different techniques (e.g. ground-based radar, digisonde, GPS, optical instruments, in situ satellite and rocket instrumentation), and its time evolution and propagation characteristics can be used to study important aspects of ionospheric dynamics and thermosphere-ionosphere coupling. At present, one of the most powerful optical techniques to study the large-scale ionospheric irregularities is the all-sky imaging photometer system, which normally measures the strong F-region nightglow 630 nm emission from atomic oxygen. The monochromatic OI 630 nm emission images usually show quasi-north-south magnetic field-aligned intensity depletion bands, which are the bottomside optical signatures of large-scale F-region plasma irregularities (also called plasma bubbles). The zonal drift velocities of the plasma bubbles can be inferred from the space-time displacement of the dark structures (low intensity regions) seen on the images. In this study, images obtained with an all-sky imaging photometer, using the OI 630 nm nightglow emission, from Cachoeira Paulista (22.7° S, 45° W, 15.8° S dip latitude), Brazil, have been used to determine the nocturnal monthly and latitudinal variation characteristics of the zonal plasma bubble drift velocities in the low latitude (16.7° S to 28.7° S) region. The east and west walls of the plasma bubble show a different evolution with time. The method used here is based on the western wall of the bubble, which presents a more stable behavior. Also, the observed zonal plasma bubble drift velocities are compared with the thermospheric zonal neutral wind velocities obtained from the HWM-90 model (Hedin et al., 1991) to investigate the thermosphere-ionosphere coupling. Salient features from this study are presented and discussed.Key words. Ionosphere (ionosphere-atmosphere interactions; ionospheric irregularities; instruments and techniques)

scholarly journals Storm-time longitudinally propagating asymmetric modes at low latitudes

2012 ◽  
Vol 30 (1) ◽  
pp. 131-141 ◽  
Author(s):  
A. K. Singh ◽  
A. K. Sinha ◽  
R. Rajaram ◽  
B. M. Pathan
Keyword(s):  
Local Time ◽  
Ring Current ◽  
Detailed Examination ◽  
Global Scale ◽  
Low Latitude ◽  
Asymmetric Component ◽  
Low Latitudes ◽  
Magnetometer Data ◽  
Current Region ◽  
Rotation Of The Earth

Abstract. The westward flowing toroidal ring current at about 2–7 RE in the Earth's equatorial plane consists of symmetric and asymmetric parts. Zonal mean of H disturbances from longitudinally distributed low latitude stations represents the symmetric contribution, whereas departure from the zonal mean gives local time dependent asymmetric component at each of the stations. Through a standard analysis of closely spaced low latitude geomagnetic data we demonstrate 24 h periodicity in the asymmetric component of the storm-time ring current, which is related to the changing local time due to rotation of the Earth. Detailed examination of shorter period oscillations, when observed globally, often show westward propagating modes. Eastward propagating mode was also observed in one case. Based on satellite and radar observations covering a narrow longitude region, westward and eastward propagating modes had been reported in earlier studies. In this study, we report that similar propagating modes which are available on global scale, can be identified using ground-based magnetometer data. These globally propagating modes, observed from ground-based studies, find obvious practical application in diagnostics of the magnetosphere, especially the ring current region. Simultaneous use of satellite and ground-based data should establish the morphology of such modes.

scholarly journals Intermediate Layers responses to Geomagnetic Activity During the 2009 Deep Solar Minimum Over the Brazilian Low Latitude Sector

2021 ◽  
Author(s):  
Ângela Santos ◽  
Christiano Brum ◽  
Inez Batista ◽  
José Sobral ◽  
Mangalathayil Abdu ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Solar Minimum ◽  
Early Morning ◽  
Low Latitude ◽  
Seasonal Behavior ◽  
F Region ◽  
Intermediate Layers ◽  
Bottom Side ◽  
E Region ◽  
First Time

Abstract. Intermediate layers (ILs) are regions of enhanced electron density located in the ionospheric valley that extends from the peak altitude of the daytime E-region to the bottom side of the F-region. This work presents the daytime behavior of the ILs parameters (the virtual height - h’IL, and the top frequency - ftIL) over the low latitude region of Cachoeria Paulista (CP, 22.42° S; 45° W, I: −34.4°) for the deepest solar minimum of the last 500 years. In such a unique condition, this research reveals for the first time the ILs' quiet state seasonal behavior as well as its responses to moderate changes in the geomagnetic activity. The main results show that even small variations of geomagnetic activity (quantified by the planetary Kp index) are able to modify the dynamics of the ILs parameters. For the first time, it was observed that during the summer, the h’IL decrease rapidly with the increase of geomagnetic activity mainly in the early morning hours. In the following hours, a smoothed rise of the IL was found in all seasons analyzed. Regarding to frequency, it was observed that after 12:00 LT, there is a tendency of it decreased with the increase of the magnetic disturbances, being this characteristic more intense after 16:00 LT, except in the equinox, when little or no response was found during all the interval analyzed. In addition, it stands out that the annual periodicity of the ftIL was observed while the h’IL presents semiannual component.

scholarly journals The study of equatorial plasma bubble during January to April 2012 over Kolhapur (India)

2016 ◽  
Vol 59 (2) ◽  
Author(s):  
Parashram T. Patil ◽  
Rupesh N. Ghodpage ◽  
Alok K. Taori ◽  
Rohit P. Patil ◽  
Subramanian Gurubaran ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Emission Line ◽  
Drift Velocity ◽  
Velocity Variation ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Observation Period

<p>Over 53 nights of all sky airglow imager data collected during January-April 2012 from the low latitude station Kolhapur (16.68°N, 74.26°E; 10.6°N dip latitude) have been analyzed to study the F-region dynamics through the imaging of OI 630 nm emission line. The observed night airglow data were supported by the ionosonde measurements from Tirunelveli (8.7°N, 77.8°E; 0.51°N dip latitude). Well defined magnetic field aligned depletions were observed during the observation period. Out of 53 nights, 40 nights exhibited the occurrence of north-south aligned equatorial plasma bubbles. These plasma bubbles were found moving towards east with drift speed in range between 70 to 200 m s<span><sup>-1</sup></span>. We have analyzed the zonal drift velocity variation and relation of bubble occurrence with the base height of the ionosphere together with the effects of the geomagnetic Ap and solar flux F<span><sub>10.7</sub></span> cm index in its first appearance.</p>

scholarly journals Comparative investigations of equatorial electrodynamics and low-to-mid latitude coupling of the thermosphere-ionosphere system

2006 ◽  
Vol 24 (2) ◽  
pp. 503-513 ◽  
Author(s):  
M. J. Colerico ◽  
M. Mendillo ◽  
C. G. Fesen ◽  
J. Meriwether
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Circulation Model ◽  
Upper Atmosphere ◽  
Low Latitude ◽  
Brightness Wave ◽  
F Region ◽  
Fabry Perot ◽  
Low Latitudes ◽  
First Time

Abstract. The thermospheric midnight temperature maximum (MTM) is a highly variable, but persistent, large scale neutral temperature enhancement which occurs at low latitudes. Its occurrence can impact many fundamental upper atmospheric parameters such as pressure, density, neutral winds, neutral density, and F-region plasma. Although the MTM has been the focus of several investigations employing various instrumentation including photometers, satellites, and Fabry-Perot interferometers, limited knowledge exists regarding the latitude extent of its influence on the upper atmosphere. This is largely due to observational limitations which confined the collective geographic range to latitudes within ±23°. This paper investigates the MTM's latitudinal extent through all-sky imaging observations of its 6300Å airglow signature referred to by Colerico et al. (1996) as the midnight brightness wave (MBW). The combined field of view of three Southern Hemisphere imaging systems located at Arequipa, Peru, and Tucuman and El Leoncito, Argentina, for the first time extends the contiguous latitudinal range of imager observations to 8° S-39° S in the American sector. Our results highlight the propagation of MBW events through the combined fields of view past 39° S latitude, providing the first evidence that the MTM's effect on the upper atmosphere extends into mid-latitudes. The observations presented here are compared with modeled 6300Å emissions calculated using the NCAR thermosphere-ionosphere-electrodynamic general circulation model (TIEGCM) in conjunction with an airglow code. We report that at this time TIEGCM is unable to simulate an MBW event due to the model's inability to reproduce an MTM of the same magnitude and occurrence time as those observed via FPI measurements made from Arequipa. This work also investigates the origins of an additional low latitude airglow feature referred to by Colerico et al. (1996) as the pre-midnight brightness wave (PMBW) and described as an enhancement in 6300Å emission which occurs typically between 20:00-22:00 LT and exhibits equatorward propagation. We present the first successful simulation of a PMBW event using the TIEGCM and the airglow code. We find that the PMBW's origin is electro-dynamical in nature, resulting from the expected evening decay of the inter-tropical arcs.

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