On the Need to Reparametrize the OVATION Prime (2010) Auroral Precipitation Model

2021 ◽  
Vol 3 ◽  
pp. 86-94
Author(s):  
A. V. Nikolaev ◽  
Keyword(s):  
Correlation Coefficient ◽  
Satellite Data ◽  
Time Delays ◽  
Coupling Function ◽  
Active Particle ◽  
Polar Cap ◽  
Particle Precipitation ◽  
Precipitation Model ◽  
Polar Satellite

The need to reparametrize the OVATION Prime (2010) empirical auroral precipitation model using the Russian polar cap index (PC index) is considered. For this purpose, the integrated auroral power of particle precipitation obtained from the Polar satellite data for the period from December 1996 to June 1998 is compared with the PC index and the Newell’s coupling function. The analysis revealed that the PC index at the time delays up to 5–20 minutes correlates with the magnitude of auroral power much better (the correlation coefficient R ~ 0.76–0.87) than the Newell’s coupling function (R ~ 0.46–0.82). Thus, for the purpose of nowcasting the zone of active particle precipitation, the PC index showed much higher scores, although the predicting abilities of the Newell’s coupling function for the time delays of more than 20 minutes remain the best.

scholarly journals Polar patches observed by ESR and their possible origin in the cusp region

2000 ◽  
Vol 18 (9) ◽  
pp. 1043-1053 ◽  
Author(s):  
A. M. Smith ◽  
S. E. Pryse ◽  
L. Kersley
Keyword(s):  
Energy Distribution ◽  
Electron Density ◽  
Plasma Flow ◽  
Plasma Temperature ◽  
Soft Particle ◽  
Polar Ionosphere ◽  
Polar Cap ◽  
Particle Precipitation ◽  
Cusp Region ◽  
Reconnection Site

Abstract. Observations by the EISCAT Svalbard radar in summer have revealed electron density enhancements in the magnetic noon sector under conditions of IMF Bz southward. The features were identified as possible candidates for polar-cap patches drifting anti-Sunward with the plasma flow. Supporting measurements by the EISCAT mainland radar, the CUTLASS radar and DMSP satellites, in a multi-instrument study, suggested that the origin of the structures lay upstream at lower latitudes, with the modulation in density being attributed to variability in soft-particle precipitation in the cusp region. It is proposed that the variations in precipitation may be linked to changes in the location of the reconnection site at the magnetopause, which in turn results in changes in the energy distribution of the precipitating particles.Key words: Ionosphere (ionosphere-magnetosphere interactions; plasma temperature and density; polar ionosphere)

scholarly journals Toward a next generation particle precipitation model: Mesoscale prediction through machine learning (a case study and framework for progress)

Space Weather ◽  
2021 ◽  
Author(s):  
Ryan M. McGranaghan ◽  
Jack Ziegler ◽  
Téo Bloch ◽  
Spencer Hatch ◽  
Enrico Camporeale ◽  
...  
Keyword(s):  
Machine Learning ◽  
Next Generation ◽  
Particle Precipitation ◽  
Precipitation Model

scholarly journals Strong sunward propagating flow bursts in the night sector during quiet solar wind conditions: SuperDARN and satellite observations

2002 ◽  
Vol 20 (6) ◽  
pp. 771-779 ◽  
Author(s):  
C. Senior ◽  
J.-C. Cerisier ◽  
F. Rich ◽  
M. Lester ◽  
G. K. Parks
Keyword(s):  
Convective Transport ◽  
High Time Resolution ◽  
Polar Cap ◽  
Particle Precipitation ◽  
Phase Velocities ◽  
Plasma Injection ◽  
Night Side ◽  
Magnetospheric Boundaries ◽  
Auroral Particle Precipitation ◽  
Imf Clock Angle

Abstract. High-time resolution data from the two Iceland SuperDARN HF radars show very strong nightside convection activity during a prolonged period of low geomagnetic activity and northward interplanetary magnetic field (IMF). Flows bursts with velocities ranging from 0.8 to 1.7 km/s are observed to propagate in the sunward direction with phase velocities up to 1.5 km/s. These bursts occur over several hours of MLT in the 20:00–01:00 MLT sector, in the evening-side sunward convection. Data from a simultaneous DMSP pass and POLAR UVI images show a very contracted polar cap and extended regions of auroral particle precipitation from the magnetospheric boundaries. A DMSP pass over the Iceland-West field-of-view while one of these sporadic bursts of enhanced flow is observed, indicates that the flow bursts appear within the plasma sheet and at its outward edge, which excludes Kelvin-Helmholtz instabilities at the magnetopause boundary as the generation mechanism. In the nightside region, the precipitation is more spot-like and the convection organizes itself as clockwise U-shaped structures. We interpret these flow bursts as the convective transport following plasma injection events from the tail into the night-side ionosphere. We show that during this period, where the IMF clock angle is around 70°, the dayside magnetosphere is not completely closed.Key words. Ionosphere (Auroral ionosphere; Ionospheremagnetosphere interactions; Particle precipitation)

Electron Acceleration and Subsecond Time Delays of Hard X-Rays of Solar Flares According to Lomonosov Satellite Data

2018 ◽  
Vol 56 (6) ◽  
pp. 420-425
Author(s):  
Yu. T. Tsap ◽  
I. N. Myagkova ◽  
Yu. G. Kopylova ◽  
G. G. Motorina ◽  
A. V. Bogomolov ◽  
...  
Keyword(s):  
Satellite Data ◽  
Solar Flares ◽  
Time Delays ◽  
Electron Acceleration ◽  
X Rays

scholarly journals Freeboard, snow depth and sea-ice roughness in East Antarctica from in situ and multiple satellite data

2011 ◽  
Vol 52 (57) ◽  
pp. 242-248 ◽  
Author(s):  
Thorsten Markus ◽  
Robert Massom ◽  
Anthony Worby ◽  
Victoria Lytle ◽  
Nathan Kurtz ◽  
...  
Keyword(s):  
Sea Ice ◽  
Correlation Coefficient ◽  
Satellite Data ◽  
Snow Depth ◽  
Large Scale ◽  
Mean Difference ◽  
Laser Altimeter ◽  
In Situ Data ◽  
Ice Roughness

AbstractIn October 2003 a campaign on board the Australian icebreaker Aurora Australis had the objective to validate standard Aqua Advanced Microwave Scanning Radiometer (AMSR-E) sea-ice products. Additionally, the satellite laser altimeter on the Ice, Cloud and land Elevation Satellite (ICESat) was in operation. To capture the large-scale information on the sea-ice conditions necessary for satellite validation, the measurement strategy was to obtain large-scale sea-ice statistics using extensive sea-ice measurements in a Lagrangian approach. A drifting buoy array, spanning initially 50 km × 100 km, was surveyed during the campaign. In situ measurements consisted of 12 transects, 50–500 m, with detailed snow and ice measurements as well as random snow depth sampling of floes within the buoy array using helicopters. In order to increase the amount of coincident in situ and satellite data an approach has been developed to extrapolate measurements in time and in space. Assuming no change in snow depth and freeboard occurred during the period of the campaign on the floes surveyed, we use buoy ice-drift information as well as daily estimates of thin-ice fraction and rough-ice vs smooth-ice fractions from AMSR-E and QuikSCAT, respectively, to estimate kilometer-scale snow depth and freeboard for other days. the results show that ICESat freeboard estimates have a mean difference of 1.8 cm when compared with the in situ data and a correlation coefficient of 0.6. Furthermore, incorporating ICESat roughness information into the AMSR-E snow depth algorithm significantly improves snow depth retrievals. Snow depth retrievals using a combination of AMSR-E and ICESat data agree with in situ data with a mean difference of 2.3 cm and a correlation coefficient of 0.84 with a negligible bias.

Determining the Polar Cusp Longitudinal Location from Pc5 Geomagnetic Field Measurements at a Pair of High Latitude Stations

2017 ◽  
Vol 13 (S335) ◽  
pp. 139-141
Author(s):  
Stefania Lepidi ◽  
Patrizia Francia ◽  
Lili Cafarella ◽  
Domenico Di Mauro ◽  
Martina Marzocchetti
Keyword(s):  
Magnetic Field ◽  
Satellite Data ◽  
High Latitude ◽  
Geomagnetic Field ◽  
Geomagnetic Latitude ◽  
Low Frequency ◽  
Field Measurements ◽  
Polar Cap ◽  
Polar Cusp ◽  
Local Noon

AbstractWe use low frequency geomagnetic field measurements at two Antarctic stations to statistically investigate the longitudinal location of the polar cusp. The two stations are both located in the polar cap at a geomagnetic latitude close to the cusp latitude; they are separated by one hour in magnetic local time. At each station the Pc5 power maximizes when the station approaches the cusp, i.e. around magnetic local noon. The comparison between the Pc5 power at the two stations allows to determine the longitudinal location of the cusp. Our analysis is conducted considering separately different orientation of the interplanetary magnetic field. The results, which indicate longitudinal shifts of the polar cusp depending on the selected conditions, are discussed in relation to previous studies of the polar cusp location based on polar magnetospheric satellite data.

scholarly journals Influence of different types of ionospheric disturbances on GPS signals at polar latitudes

2021 ◽  
Author(s):  
Vladimir B. Belakhovsky ◽  
Yaqi Jin ◽  
Wojciech J. Miloch
Keyword(s):  
Interplanetary Shock ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Polar Cap ◽  
Particle Precipitation ◽  
Total Electron ◽  
Different Types ◽  
Interplanetary Shock Wave ◽  
Using Data ◽  
Auroral Particle Precipitation

Abstract. The comparative research of the influence of different types of auroral particle precipitation and polar cap patches (PCP) on the GPS signals disturbances in the polar ionosphere was done. For this purpose, we use the GPS scintillation receivers at Ny-Ålesund and Skibotn, operated by the University of Oslo. The presence of the auroral particle precipitation and polar cap patches was determined by using data from the EISCAT 42 m radar on Svalbard. The optical aurora observations in 557.7 nm, 630.0 nm spectrum lines on Svalbard were used as well for the detection of ionospheric disturbances. The cusp identification was done with using SuperDARN (Hankasalmi) data. We consider about 150 events when the simultaneous EISCAT 42 m and GPS data were available for the 2010–2017 years, in paper we present in detail only typical examples describing the overall picture. It was considered the dayside/cusp precipitation, substorm precipitations, daytime and nighttime PCP, precipitation associated with the interplanetary shock wave arrival. Cusp phase scintillations are lower than dayside PCP scintillations. We demonstrate that substorm-associated precipitations (even without PCP) can lead to a strong GPS phase (σϕ) scintillations up to ~2 radians which is much stronger than those usually produced by other types of the considered ionosphere disturbances. At the same PCPs can lead to stronger ROT (rate of total electron content) variations. So our observations suggest that the substorms and PCPs, being different types of the high-latitude disturbances, lead to the development of different types and scales of ionospheric irregularities.

The Role of Satellite Data in the Forecasting of Hurricane Sandy

2014 ◽  
Vol 142 (2) ◽  
pp. 634-646 ◽  
Author(s):  
Tony McNally ◽  
Massimo Bonavita ◽  
Jean-Noël Thépaut
Keyword(s):  
New Jersey ◽  
Satellite Data ◽  
Large Scale ◽  
Hurricane Sandy ◽  
Satellite Observations ◽  
Atmospheric Flow ◽  
Performance Loss ◽  
Geostationary Satellites ◽  
Polar Satellite

Abstract The excellent forecasts made by ECMWF predicting the devastating landfall of Hurricane Sandy attracted a great deal of publicity and praise in the immediate aftermath of the event. The almost unprecedented and sudden “left hook” of the storm toward the coast of New Jersey was attributed to interactions with the large-scale atmospheric flow. This led to speculation that satellite observations may play an important role in the successful forecasting of this event. To investigate the role of satellite data a number of experiments have been performed at ECMWF where different satellite observations are deliberately withheld and forecasts of the hurricane rerun. Without observations from geostationary satellites the correct landfall of the storm is still reasonably well predicted albeit with a slight timing shift compared to the control forecast. On the other hand, without polar-orbiting satellites (which represent 90% of the volume of currently ingested observations) the ECMWF system would have given no useful guidance 4–5 days ahead that the storm would make landfall on the New Jersey coast. Instead the hurricane is predicted to stay well offshore in the Atlantic and hit the Maine coast 24 h later. If background errors estimated from the ECMWF Ensemble of Data Assimilations (EDA) are allowed to evolve and adapt to the depleted observing system, then some of the performance loss suffered by withholding polar satellite data can be recovered. The use of the appropriate EDA errors results in a more enhanced use of geostationary satellite observations, which partly compensates for the loss of polar satellite data.

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