5 research outputs found
Tree file
The file contains a topological tree of species included in our analyse
R code
This R file contains selected examples necessary to reproduce our analyses using the accompanied data set. The file is kept as readable as possible by leaving out repleted codes. This code has been written by Tsukushi Kamiya, who can be contacted via philophthalmus-at-gmail-dot-com.
The file consists of the five following sections:
# 1. Main analyses.
# 2. DIC-based model selection.
# 3. Unconditional estimates.
# 4. Forest plot.
# 5. Tests for publication bias
Combining incoherent scatter radar data and IRI-2007 to monitor the open-closed field line boundary during substorms
[1] The size of the polar cap is very important for understanding the substorm process as well as reconnection rates in general. In this work we build on previous studies which use a combination of European Incoherent Scatter radar (EISCAT) electron temperature (Te) measurements from two radars running simultaneously to track the motion of the open-closed field line boundary (OCB). The second radar gives an estimate of the background variation of Te with altitude, which can then be subtracted from the radar beam being used to estimate the OCB location. We demonstrate that using the international reference ionosphere 2007 (IRI-2007) model can remove the second radar requirement and therefore increase the number of cases which could benefit from background Te subtraction. In this paper we focus our analysis on substorm intervals. We find that the IRI-2007 method produces an OCB proxy location which on average is 0.25° altitude adjusted corrected geomagnetic coordinate latitude equatorward of the two-radar method. On comparing both the two-radar and IRI-2007 Te OCB finding methods with the OCB identified in the DMSP particle data and IMAGE satellite data we find that both EISCAT methods perform quite well, and neither method is particularly favored over the other. We find that the magnitude of the mean offset to the IMAGE OCB varies between 0.1° and 2.7° latitude, dependent on the event and the IMAGE camera used
EISCAT observations of pump-enhanced plasma temperature and optical emission excitation rate as a function of power flux
[1] We analyze optical emissions and enhanced electron temperatures induced by high power HF radio waves as a function of power flux using the EISCAT heater with a range of effective radiated powers. The UHF radar was used to measure the electron temperatures and densities. The Digital All Sky Imager was used to record the 630.0 nm optical emission intensities. We quantify the HF flux loss due to self-absorption in the D-region (typically 3–11 dB) and refraction in the F-region to determine the flux which reaches the upper-hybrid resonance height. We find a quasi-linear relationship between the HF flux and both the temperature enhancement and the optical emission excitation rate with a threshold at ∼37.5 μWm−2. On average ∼70% of the HF flux at the upper-hybrid resonance height goes in to heating the electrons for fluxes above the threshold compared to ∼40% for fluxes below the threshold