Space & Atmospheric Sciences  Space Weather Monitoring

 

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Space Weather Monitoring

 

 

Space Weather

 

Ionosphere

 

Geomagnetism

 

Research Studies

 

New Moon Prediction

 

Space Weather

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As we go out into space, the atmosphere becomes very thin but in space there are some atoms (ambient plasma and electrically charged particles) which are often moving very quickly. Many forms of energy including magnetic fields and electromagnetic radiation also move through space and it is the interaction of energy and charged particles that produces what we refer to as space weather. In particular, space weather is the changes that occur in the space environment.

The sun is a huge generator of power (4 x 1020 MW) and is the primary (but not the only) source of space weather. Its output varies over a period of 11 years. Space weather is greatly influenced by the speed and density of the solar wind and interplanetary magnetic field (IMF) carried by solar wind plasma. A variety of physical phenomena are associated with space weather, including geomagnetic storms and substorms, energization of the Van Allen radiation belts, ionospheric disturbances and scintillation, aurora and currents induced geomagnetically at Earth’s surface.

Occasionally a huge release of magnetic energy, called a solar flare, occurs on the Sun. Flares can produce large quantities of x-rays which affect the Earth's atmosphere. They can also accelerate atomic particles (mostly protons) to very high speeds. These high energy particles are dangerous to space based technologies and manned flights as radiation can reach the stratosphere where jetliners fly.

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Importance of Space Weather Monitoring

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Most aspects of space weather affect us to some extent. The more our society becomes dependent on technology and the more we utilize space, the more we are affected by space weather. Some aspects of space weather are benevolent, and allow activities otherwise not possible such as long range radio communications. Some aspects are benign but fascinating such as the Aurora, and some are malevolent like terrestrial weather, it sometimes depends on the situation and the event. Energetic events on the sun, the bursts of solar wind materials affect geomagnetic field and ionosphere of the earth. A variety of activities and systems are greatly affected by space weather, as mentioned below:

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Satellites operations (hardware / software)

 

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Manned space flights

 

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Navigation systems

 

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General electric control systems

 

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Long-distance Pipe lines & Power lines

 

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Surveillance radars

 

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High Frequency (HF) Radio Systems

 

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Short-wave frequency broadcasting

 

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Geophysical Exploration Activities

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Since the space weather sheds dire impacts on technology of daily human use, hence monitoring of space weather conditions on regular basis becomes more important.

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Solar Flare & its effects on HF Communications

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Sometimes HF communication is completely cut off for a period of 15 to 60 minutes due to excited state of the Sun termed as Solar Flare. During a Solar Flare, a burst of enhanced ultraviolet radiation and X-rays enters the Earth's atmosphere in about 8 minutes. If solar flare is mild, only lower range of frequencies is curtailed so that the range of usable frequencies is narrowed.

 

Erupting Solar Flare

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SUPARCO’s Services in the realm of Space Weather Monitoring

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Issuance of alerts and warning for bad HF propagation conditions

 

Ionospheric Data Bulletins

 

MUF/ FOT Predictions

 

Geomagnetic parameters baselines

 

Geomagnetic Storms (effects and duration)

 

Issue warning to HF communication users

 

Local geomagnetic activity (K) index

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Ionosphere

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The ionosphere is a highly ionized region of the atmosphere lying in the altitude range 60 km to 1000 km. The ionization of the earth's atmosphere, that produces the ionosphere, is caused by several mechanisms. These mechanisms include the emission of sun's Extreme Ultra Violet (EUV), X-ray, and Lyman radiations together with solar cosmic rays. The rate of ionization at a specific altitude depends on the atmospheric composition as well as the characteristics of the incident solar radiation at that height. As the solar radiation propagates down through the neutral atmosphere the various frequency (energy) bands of this radiation are attenuated at different rate. Consequently, different ionization processes become predominant at different heights resulting in a layered structure. The principal layers/regions are designated as D-region, E-region and F-region, each being characterized by a different set of ionization processes. Some of these regions are themselves layered or structured into the E, Es, F1 and F2 regions. The number of layers, their heights and their ionization intensity vary with time in space.

The ionosphere is mainly formed by the radiation of the sun and therefore it can be severely disturbed due to solar phenomena. This degrades the ionospheric "mirror" that reflects High Frequency (HF) radio signals back to the Earth allowing cheap and convenient communication over a wide range of distances. HF is significant for many agencies including defense, emergency services, broadcasters, and marine and aviation operators. High-Frequency communicators probably represent the largest group affected by solar storms. Communications on other frequencies, from VLF to satellite, may also be affected, making space weather and its prediction an essential factor in successful operations.

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Vertical Ionospheric Soundings

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The most widely used instrument for monitoring the ionosphere is Ionosonde / ionospheric sounder. An ionospheric sounder uses basic radar techniques to detect the electron density of ionosphere as a function of height. It is high frequency radar, which sends very short pulses of radio waves vertically into the ionosphere and measures the time, which elapses before its echoes are received.

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SUPARCO’s Ionospheric Monitoring Program

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The ionosphere has temporal variation i.e. at a given location it varies diurnally, seasonally, annually and cyclically of 11-year solar cycle. The ionosphere also varies significantly from one place to the other, which is known as spatial variation and is different from the temporal one. The variations in the ionosphere make pronounced effects on HF communication therefore it is necessary to understand fully the spatial variation of the ionosphere. For national HF users and research studies, SUPARCO keeps a constant tab on the temporal variations taking place in the ionosphere over Pakistan, so that its behavior is fully understood. The behavior of the ionosphere is needed to be understand completely and in order to predict the most optimum radio wave frequencies for communication between two given places via the ionosphere to our HF users.

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Ionospheric Soundings Facilities

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In order to understand fully the temporal as well as spatial variations taking place in the ionosphere over Pakistan, it is necessary to probe the ionosphere using ionospheric sounding equipments. For this purpose SUPARCO had started ionospheric sounding in Pakistan as early as 1973.The most widely used instrument for monitoring the ionosphere is ionosonde / ionospheric sounder. An ionospheric sounder uses basic radar techniques to detect the electron density of ionosphere as a function of height. It is high frequency radar, which sends very short pulses of radio waves vertically into the ionosphere and measures the time, which elapses before its echoes are received. SUPARCO presently operates three Vertical Ionospheric Sounding Stations, one each at Islamabad, Multan and Sonmiani, for monitoring local ionosphere round the clock at 15-minute intervals. At Sonmiani and Islamabad, Digisonde (DGS-256) are being operated whereas at Multan Digisonde Portable Sounder (DPS-4) has been made operational since April 2008.

 

 

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Geomagnetism

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Our planet is surrounded by a protective shield generated by the Earth’s Magnetic Field. The geomagnetic field is produced by the dynamo action within the molten iron in the outer core. This is a dynamic process intimately linked to the cooling of the core and the rapid spin of the Earth. The electric currents flowing in the ionosphere are also a contributing factor in the variation of the geomagnetic field. Apart from that, the sun bursting with flares and ejections continuously blows charged particles and disconnected magnetic field lines which interacts with the geomagnetic field giving rise to space weather & climate. Earth’s magnetic field plays a vital role in the formation/ creation of space weather and thus has a very pronounced effect on it. In recent years, monitoring of the earth’s magnetic field has become important for the mitigation of the impacts of space weather.

In order to study its effects on space weather, we need to untangle the rich information of the magnetic field so that we can better understand our planet and the surrounding space environment in which it resides. Obviously, it would be a daunting task to study and understand all the aspects of Earth’s magnetic field. It is necessary to concentrate on those phenomena that can be monitored and studied with data collected from the ground-based magnetic observatory network.

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Magnetic Storms

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If the magnetic storm is unusually severe, High Frequencies become unusable. However, during a mild storm, communication may be possible by using a lower frequency. Currents flowing in the ionosphere pose a hazard to artificial satellites, during magnetic storm, when build-up of charge on electrical components can cause damage.

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Magnetogram showing the severe magnetic storm recorded at Sonmiani

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SUPARCO’s Geomagnetic Field Monitoring Program

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The objective of the program is to monitor the variation in the regional geomagnetic field components and to maintain its accuracy. Using ground based observatories at Islamabad and Sonmiani, the program provides the basis for the continuous records of magnetic field variation, scientific research and dissemination of data to various national and international institutions. SUPARCO conducts research into the nature of geomagnetic variations for the purposes of scientific understanding and hazard mitigation. For this purpose SUPARCO had started geomagnetic field monitoring in Karachi, Pakistan as early as 1983. The monitoring activity has been initiated in Islamabad and Sonmiani from July 2008.

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Observatories Details

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Monthly bulletin of geomagnetic data are prepared and provided to national and international users. Information on the ‘sfe’ (solar flare effects) and severe magnetic storms recorded by observatories is passed on, as alert/ warning regarding the bad conditions for HF communications, to users.

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Monitoring Facilities

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SUPARCO has recently established two geomagnetic observatories at Islamabad and Sonmiani. The observatories have been in operation since their establishment in 2008 where dIdD (delta Inclination delta Declination) systems and LAMA variometers have been installed to accurately measure the temporal variations in the geomagnetic field. A declinometer/inclinometer (DIM) fluxgate magnetometer Zeiss THEO 010 is manually operated 2-3 times in a week to take absolute measurements of the direction of the geomagnetic field to calibrate baselines. It consists of a single-axis fluxgate sensor mounted on the telescope of a non-magnetic theodolite. A brief overview of sensor information is provided below. Both observatories are affiliated with International Magnetic Observatories Network (INTERMAGNET).

 

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Sensors/Instruments Info

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Future Plans

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In response to the rapidly evolving science of geomagnetism and ever more stringent demands of the scientific community, SUPARCO keeps its observatories network upgraded and modernized.

Magnetic anomaly map play a key role in developing the theory of plate tectonics and unravelling the structure of Earth’s lithosphere. The primary objective of SUPARCO is to keep vigilance on the regional magnetic anomaly to contribute in World Data Magnetic Anomaly Map (WDMAM). SUPARCO’s aim is to produce a digital map and anomalies database to giving an overview of the anomaly pattern for the region as a scientific contribution to knowledge and an important new insight into the geological evolution of our country. In this perspective, SUPARCO is hopeful of initiating an Aeromagnetic Survey in the adjoining areas of Sindh & Balochistan giving an opportunity to explore the area for mineral exploration and magnetic anomalies all the same.

 

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Research Studies

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Study of maximum electron density NmF2 at Karachi and Islamabad during solar minimum (1996) and solar maximum (2000) and its comparison with IRI

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The following results have been obtained from this study:

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NmF2 studies with data from Karachi and Islamabad for solar minimum (1996) and solar maximum (2000) show that the Karachi values are consistently larger.

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Karachi lies in the equatorial anomaly region whereas Islamabad lies outside.

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Bite-outs in the diurnal NmF2 variations are more prevalent in solar minimum than solar maximum years.

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The occurrence of pre-noon, noon, and post-noon bite-outs is most prevalent in January at low solar activity.

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Comparing IRI and regional model with Ionosonde measurements in Pakistan

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The following results have been obtained from this study:

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Model values (IRI and regional) showed an overall good agreement with the observed data (foF2 & foE) during daytime.

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Model values (IRI and regional) showed considerable differences with observed monthly medians of foF2 during nighttime and at the time of sunset/sunrise in foE. The deviation can be referred to decrease in electron density at night.

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During the day-time the difference between predicted & observed values of foF2 was lower than those of night-time

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Model values (IRI and regional) were closer to the observed monthly medians of foF2 at higher latitude than for lower latitudes (in Pakistan).

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Good agreement was found between the two model values for hmF2 whereas both models were not convergent for YmF2.

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Both models showed variation around sunrise and sunset because of the sharp gradient in electron density.

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The techniques adopted will be useful in frequency prediction.

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Effects of earthquake of 8 October 2005 on the Geomagnetic Field at Karachi, Pakistan

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The following results have been obtained from this study:

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Signs of pre and immediate-effects of the earthquake are noticeable in the digital F-data recorded at 1-minute intervals with an accuracy of 0.4 nT presents

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Sharp shift in the aperiodic waves of local field F appears 2 to 7-days before the occurrence of earthquake

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Aperiodic oscillation of 40 to 70 nT with periods from 2 to 4 hours in the local F-field are produced 2-days before the onset.

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A wave of amplitude 52 nT and period 23 hours 47 minutes in the local F is produced about 2 to 3 days before the occurrence of earthquake

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Decrease in the mean monthly % occurrence of aperiodic oscillations of different amplitude is observed:

 

 

The mean monthly occurrence of the amplitude A1 and A2 reduces to 11.14% and 57.82 % respectively one month before the occurrence of earthquake

The mean monthly occurrence of the amplitude A3 and A4 reduces to 23.95% and 1.3 % respectively one month before the occurrence of earthquake

The mean monthly occurrence of the amplitude A4 increases to a 6.76 % during the month of earthquake

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New Moon Prediction

 

SUPARCO regularly provides predictions (on monthly basis) for the visibility of new moon to relevant agencies in Pakistan. Moon's parameters for sighting the new moon are predicted for various cities of Pakistan.

 

Phases of the Moon

New Moon

Waxing Crescent

First Quarter

Waxing Gibbous

Full Moon

Waning Gibbous

Last Quarter

Waning Crescent

New Moon

 

 

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