About POPDAT

Main activity of POPDAT

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Project title

Problem-oriented Processing and Database Creation for Ionosphere Exploration

Short title

POPDAT

FP-7 Direction

Activity 9.2: Strengthening Space Foundations.
Area 9.2.1: Research to support space science and exploration.
Sub-area – 9.2.1.3: Exploitation of space science and exploration data.

Duration

24 months

Key-words

Ionosphere Wave Service, Space Weather, satellite missions, data mining, database, wave processes, AGW, ELF, VLF, TID, TEC.

Abstract

The present Project purpose is the problem-oriented processing of observational data collected and stored by former ionospheric satellite missions – their data mining with the aim to create the database of ionosphere waves catalogues. This is an urgent need of modern space science because its realization will help to improve considerably Space Weather nowcast and forecast and to promote the progress of actual today GMES and other applied studies, e.g., ionospheric monitoring of natural and man-made hazards. At a first stage of the Project fulfillment, the different types of wave data will be selected, processed and arranged in topical catalogues: atmosphere gravity waves, moving plasma disturbances (bubbles, blobs, TID, etc), and ELF-VLF plasma emissions (whistler waves, hisses, etc). Then the Ionosphere Wave Service will be created including the composition of catalogues metadata to provide useful tool to access the database through a web portal. Ionosphere Wave Service will be promoted to a great number of scientists and specialists working in the numerous theoretical and applied space oriented branches, such as space physics, Solar-terrestrial connections, Space Weather, Earth observation, natural and man-made powerful hazards monitoring, satellites launches and exploration, to name a few.

The particular goals of the POPDAT Project are:

  • Collection of datasets from different sources which concern the wave-like phenomena in the upper atmosphere and ionosphere to form input data field for further processing;
  • Appropriate design of the flexible software tools for the search of wavelike and/or any other anomalous behaviors detected in the satellite datasets;
  • Creation of thematic catalogues of ionosphere perturbations, which have known, supposed or unknown origin;
  • Implementation of a Ionosphere Wave Service accessible to scientific communities and public users;
  • Integration of Ionosphere Wave Service with ULISSE information system;
  • Creation of Ionosphere Virtual Dynamic Observatory to assist educational activities;
  • Dissemination and promotion of the Ionosphere Wave Service at topical conferences and in scientific and public press.

Besides, the following Project aspects are important:

  • To target specific space science and exploration domains in which a strong need for further scientific analysis of data exists, including the necessity of such wave propagation models, which are still missing;
  • Mobilizing the best expertise to analyze and interpret of space data;
  • Extending the usage of available data through promoting its transfer and access facilitation;
  • Developing better tools to process/access/archive and distribute data obtained from different space missions.

Concept and objectives

1. Scientific background

a) Subject of investigation – dynamical processes in the ionosphere

Earth’s ionosphere is a substantial part of the solar-terrestrial interaction processes. Therefore, ionospheric plasma dynamics influenced by the active Sun becomes an important element of the Space Weather. Thus, it exhibits radio communication “break up’s”, disturbed operation of the Global Positioning Systems (GPS), ground based power stations “switch off’s” in their normal operation, etc. In parallel, Earth’s ionosphere is strongly influenced by the large scale circulation in the troposphere (typhoons), earthquakes and tsunamis (perhaps in the earthquake preparatory phase), powerful nuclear or chemical explosions, rocket launches etc. Beside these effects, which appear in the ionosphere, the ionosphere is the coupling zone between the lower atmosphere including biosphere and our civilization and the near Earth space (exosphere, plasmasphere and magnetosphere). The actual state of the ionosphere is a basic system of parameters which are important to the evolution and effects of the Space Weather phenomena. The continuous monitoring of the state of these regions is a key element in Space Weather research and applications. One of the most important tools of such monitoring is the registration and analysis of propagating sounding signals (natural or artificial) through the interesting areas. However, the propagation through the ionosphere affects the signal shapes and therefore influences the monitoring.

In this context, the study of vertical coupling in the Earth’s ionosphere with adjacent zones from above and below is an actual subject with relatively high importance and practical application. In this sense, new techniques for ionospheric data evaluation and data mining seems to be a successive solution for further studies carried out by the usage of large amount of satellite data over prolonged periods of observations. As a part of this approach, here proposed data processing procedures are addressed to the recognition and data collection of the various signatures, which conform to the specific physical phenomena already chosen by the operator.

Here proposed work should be a first step toward the creation of the third level set of physical knowledge by use of various algorithms, especially selected for wave-like structures in the Earth’s ionosphere.

Table 1. Main ionosphere satellite missions

?

Mission

Year

Orbit

Payload

1

Atmosphere Explorer - A

1963

255 - 916 km, i = 57°

Sensors for neutral and ionized species of atmospheric gazes

2

Atmosphere Explorer - B

1966

276 - 2725 km, i = 64°

-“-

3

Atmosphere Explorer - C

1973

149 - 4294 km, i = 68°

-“-, optical and UV spectrometers

4

Atmosphere Explorer - D

1975

154 - 3816 km, i = 90°

-“-

5

Atmosphere Explorer - E

1975

156 - 2983 km, i = 20°

-“-

6

Dynamics Explorer 2

1981

309 - 1012 km, i = 90°

-“-, sensors for quasi DC magnetic field, DC and AC electric field

7

SAN MARCO D/L

1988

262 - 619 km, i = 2°

Neutral wind probe, plasma probes, electric field probe

8

Active

1989

500 - 2500 km, i = 82°

Plasma probes, sensors for quasi DC electric and magnetic fields, wave probes, energetic particle probe, VLF-transmitter

9

APEX

1991

440 - 3000 km, i = 82°

-“-, electric beam and plasma injectors

10

FREJA

1992

650 - 1800 km, i = 65°

Plasma probes, high data rate wave probes, energetic particle probes, UV imager

11

ROCSat-1

1999

600 km, i = 35°

Plasma probes

12

CHAMP

2000

454 km, i = 87°

Magnetic field probes, precise accelerometer

13

Variant (on Sich-1M S/C)

2004

280 - 650 km, i = 83°

Electric probes, wave probes, electric current probes, fluxgate magnetometer

14

DEMETER

2004

~ 710 km, changed to 660 km, i = 98°

Plasma probes, electric field and AC magnetic field probes

15

Compass-2

2006

~ 400 km, i = 79º

Wave probes

b) Ionosphere satellite missions

Since the beginning of space era, almost 20 satellite missions could be summarized as pure “ionospheric”, depending on the accepted definition of this term, according to the great variability in orbital parameters of the Low Earth Orbiting satellites.

In table 1.1.1 are listed main satellite missions (including recent “DEMETER” and “CHAMP”) for in situ registration of ionosphere parameters. Missions which datasets will be used in present project are marked. In the table are omitted several relatively small projects as well as missions with remote ionosphere sensing (among them “UARS” and “TIMED” with optical observations). Nevertheless, ionosphere remote sensing capability of GPS will be used in the frame of this Project to monitor wave structures in the Total Electron Content (TEC), because this technique represents one of the most efficient ways of ionosphere diagnostics in the foreseeable future. Finally, the information concerning experiments onboard of Space Shuttles and Orbital Stations is not addressed here, because the influence of so large spacecrafts on ionospheric medium had given no possibility for detection of natural wave processes.

In the earlier stage, satellite experiments were addressed to study the main morphological features in the global distribution of the atmosphere-ionosphere parameters (altitudinal, latitudinal, diurnal etc.). At present, this stage is almost completed. Large amount of satellite data gathered during these missions are successfully integrated in the various models of the upper atmosphere and ionosphere. Upcoming data from the current missions are used for the existing model adjustment or to the development of the alternative ionospheric models.

Generally, since the Dynamics Explorer mission main task of the contemporary ionospheric physics becomes the study of the ionosphere plasma dynamics within different scales, as a result of the global coupling processes.

2. Project objectives

a) Main purpose of the Project

Data processing of the satellite experiments includes few important levels. At the first level, raw data conversion, decoding of the control parameters, removing erroneous data records, adjustment to the universal time etc., transforms the telemetry data flow to the basic electrical signals relevant to the specific application of the onboard instrumentation as a chain of equidistant records in time. Usually, this part of preliminary data processing is a first level on which user can have some overall information about the quality of data flow from given instrument. At the second level, these records of electrical values are transformed in the real physical one by the use of the next level algorithms quite specific for different experiments. At this stage, continuous flow of physical parameters is accompanied by the attitude and geophysical information corresponding to each data record in time. At this level any user can realize search over the whole data base by use of running search windows for the physical and/or geophysical parameters, retrieving average behavior of certain parameter along the satellite track, latitude, longitude etc.

At this level of data processing, physical parameters become initial source of challenging information for the user. The main purpose of the here proposed third level of the data processing is to offer an opportunity to the user, to select specific “shapes” from whole data set which correspond to the intriguing physical phenomena by use especially created software tools. For example, it could be “wave-like structures” with different scales in the ion density or “double layer” structures in quasi DC electric field, “vortexes” etc. In spite of the above mentioned first two levels of data processing, third level of data processing needs specific physical knowledge for algorithms and software tools to be accurately adjusted to the interesting cases for users. For the above mentioned cases the adjustments has to be achieved by scientific experts in wave processes in the ionosphere and by considering users requirements.

Current level of information technologies reveal realistic opportunities, third level of data mining to be used over sets of data taken from different satellites at different places and times, combined with sort of solar-geophysical data. This in fact, concerns wide range of space scientists certainly not included in the specific satellite project teams, working groups etc. but interested in data mining and interpretation.

For example, there is a cluster of scientists interested on the seismic effects in the ionosphere during preparatory phase of earthquakes. Using data base created by scientists involved in the specific projects through second level of data processing, many scientists could study different kind of phenomena associated with earthquakes such as gravity waves in the ionosphere, already included in the data set.

Our scope is that similar set “third” level data is quite effective and could be very helpful to the wide number of users in the space science community.

b) Objectives

The present Project purpose is the problem-oriented processing of observational data collected and stored by former ionospheric satellite missions – their data mining with the aim to create the database of ionosphere waves catalogues. This is an urgent need of modern space science because its realization will help to improve considerably Space Weather nowcast and forecast and to promote the progress of actual today GMES and other applied studies, e.g., ionospheric monitoring of natural and man-made hazards. At a first stage of the Project fulfillment, the different types of wave data will be selected, processed and arranged in topical catalogues: atmosphere gravity waves, moving plasma disturbances (bubbles, blobs, TID, etc), and ELF-VLF plasma emissions (whistler waves, hisses, etc). Then the Ionosphere Wave Service will be created including the composition of catalogues metadata to provide useful tool to access the database through a web portal. Ionosphere Wave Service will be promoted to a great number of scientists and specialists working in the numerous theoretical and applied space oriented branches, such as space physics, Solar-terrestrial connections, Space Weather, Earth observation, natural and man-made powerful hazards monitoring, satellites launches and exploration, to name a few.