Discovery of radiation anomalies above the South Atlantic at heights of 310–340 km

Kurnosova, L. V.; Kolobyanina, T.N.; Logachev, V. I.; Razorenov, L. A.; Sirotkin, I.A.; Fradkin, M. I.

doi:10.1016/0032-0633(62)90057-0

Cited by 22 publications

(9 citation statements)

References 3 publications

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“…The trapped radiation environment, consisting of large amounts of energetic charged particles, can be potentially harmful to human beings and space vehicles immerged in it. Since the geomagnetic field is not a perfect dipole, the inner radiation belt gets closer to the Earth over the South Atlantic Ocean, which is called the South Atlantic Anomaly (SAA) [ Kurnosova et al , ]. Exposed to stronger radiation, low‐Earth orbiting (LEO) spacecrafts suffer much higher risks of being damaged in this region.…”

Section: Introductionmentioning

confidence: 99%

Solar cycle variations of trapped proton flux in the inner radiation belt

Qin

Zhang

et al. 2014

JGR Space Physics

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Trapped proton population in the inner radiation belt is highly dense, posing a potential danger to astronauts and man-made space assets traversing through this region. While being significantly stable within timescales up to hundreds of days, inner zone proton fluxes can exhibit considerable solar cycle variations, which has not been investigated comprehensively yet. To analyze the long-term variation of the South Atlantic Anomaly (SAA), we adopt the proton flux data measured by NOAA 15 from 1999 through 2009 and perform statistical analyses on the basis of reasonable Gaussian fits. We report that the variation of the peak proton flux in the SAA is anticorrelated with that of F 10.7 during a solar cycle. There also exists a phase lag of 685 days between the solar F 10.7 flux and the proton flux. Similar features are seen for changes of the SAA distribution area, which in addition shows a rapid decrease during the solar maximum and a slow increase during the solar minimum. We also find that the region where the proton flux peaks drifts westward year by year with larger drift rates during the solar minimum. The peak region shifts southward during the solar maximum but in the opposite direction during the solar minimum with higher shift speed. Enhancements in solar wind dynamic pressure can favor the north-south drift of the SAA.

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Section: Introductionmentioning

confidence: 99%

Solar cycle variations of trapped proton flux in the inner radiation belt

Qin

Zhang

et al. 2014

JGR Space Physics

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“…They can cause failure of microprocessors aboard satellites, bias measurements of cosmic sources, and pose a health hazard to astronauts. In low-Earth orbits (LEO), at a height of several 100 km above the Earth's surface, a space vehicle encounters the most intense radiation in a region called the South Atlantic Anomaly (SAA; Kurnosova et al, 1962). In this region above the South Atlantic just off the Brazilian coast, the level of ionizing radiation can be increased by several orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

Temporal variations of strength and location of the South Atlantic Anomaly as measured by RXTE

Fürst¹,

Wilms²,

Rothschild

et al. 2009

Earth and Planetary Science Letters

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The evolution of the particle background at an altitude of ∼540 km during the time interval between 1996 and 2007 is studied using the particle monitor of the High Energy X-ray Timing Experiment on board NASA's Rossi X-ray Timing Explorer. A special emphasis of this study is the location and strength of the South Atlantic Anomaly (SAA). The size and strength of the SAA are anti-correlated with the the 10.7 cm radio flux of the Sun, which leads the SAA strength by ∼1 year reflecting variations in solar heating of the upper atmosphere. The location of the SAA is also found to drift westwards with an average drift rate of about 0.3 • /yr following the drift of the geomagnetic field configuration. Superimposed to this drift rate are irregularities, where the SAA suddenly moves eastwards and where furthermore the speed of the drift changes. The most prominent of these irregularities is found in the second quarter of 2003 and another event took place in 1999. We suggest that these events are previously unrecognized manifestations of the geomagnetic jerks of the Earth's magnetic field.

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“…This region is called the South Atlantic Anomaly (SAA, see for example Kurnosova et al, 1962) and any spacecraft which crosses this region can give false instrument readings. In our retrievals, the SNRs of the volume emission rates in the orbits that cross this region are affected by the SAA.…”

Section: Volume Emission Ratesmentioning

confidence: 99%

Retrieval of O2(1Σ) and O2(1Δ) volume emission rates in the mesosphere and lower thermosphere using SCIAMACHY MLT limb scans

Zarboo¹,

Bender²,

Burrows³

et al. 2018

Atmos. Meas. Tech.

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Abstract. We present the retrieved volume emission rates (VERs) from the airglow of both the daytime and twilight O 2 ( 1 ) band and O 2 ( 1 ) band emissions in the mesosphere and lower thermosphere (MLT). The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) onboard the European Space Agency Envisat satellite observes upwelling radiances in limb-viewing geometry during its special MLT mode over the range 50-150 km. In this study we use the limb observations in the visible (595-811 nm) and near-infrared (1200-1360 nm) bands.We have investigated the daily mean latitudinal distributions and the time series of the retrieved VER in the altitude range from 53 to 149 km. The maximal observed VERs of O 2 ( 1 ) during daytime are typically 1 to 2 orders of magnitude larger than those of O 2 ( 1 ). The latter peaks at around 90 km, whereas the O 2 ( 1 ) emissivity decreases with altitude, with the largest values at the lower edge of the observations (about 53 km). The VER values in the upper mesosphere (above 80 km) are found to depend on the position of the sun, with pronounced high values occurring during summer for O 2 ( 1 ). O 2 ( 1 ) emissions show additional high values at polar latitudes during winter and spring. These additional high values are presumably related to the downwelling of atomic oxygen after large sudden stratospheric warmings (SSWs). Accurate measurements of the O 2 ( 1 ) and O 2 ( 1 ) airglow, provided that the mechanism of their production is understood, yield valuable information about both the chemistry and dynamics in the MLT. For example, they can be used to infer the amounts and distribution of ozone, solar heating rates, and temperature in the MLT.

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Discovery of radiation anomalies above the South Atlantic at heights of 310–340 km

Cited by 22 publications

References 3 publications

Solar cycle variations of trapped proton flux in the inner radiation belt

Solar cycle variations of trapped proton flux in the inner radiation belt

Temporal variations of strength and location of the South Atlantic Anomaly as measured by RXTE

Retrieval of O<sub>2</sub>(<sup>1</sup>Σ) and O<sub>2</sub>(<sup>1</sup>Δ) volume emission rates in the mesosphere and lower thermosphere using SCIAMACHY MLT limb scans

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Discovery of radiation anomalies above the South Atlantic at heights of 310–340 km

Cited by 22 publications

References 3 publications

Solar cycle variations of trapped proton flux in the inner radiation belt

Solar cycle variations of trapped proton flux in the inner radiation belt

Temporal variations of strength and location of the South Atlantic Anomaly as measured by RXTE

Retrieval of O&lt;sub&gt;2&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;Σ) and O&lt;sub&gt;2&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;Δ) volume emission rates in the mesosphere and lower thermosphere using SCIAMACHY MLT limb scans

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Retrieval of O<sub>2</sub>(<sup>1</sup>Σ) and O<sub>2</sub>(<sup>1</sup>Δ) volume emission rates in the mesosphere and lower thermosphere using SCIAMACHY MLT limb scans