DMSP Satellite Data Research Articles

Features of the Structure of the Winter Morning High- and Mid-Latitude Ionosphere

The structure of the winter morning (0500–0900 LT) ionosphere in the Northern and Southern hemispheres is studied in detail. For this, CHAMP satellite data for quiet conditions during the period of high solar activity of 2000–2002 are used. Careful analysis is used to identify electron concentration troughs: the high-latitude ionospheric trough; subauroral, or main, ionospheric trough; and mid-latitude ring ionospheric trough. In order to identify and separate the high-latitude and main ionospheric troughs, the model of auroral diffuse precipitation of the Polar Geophysical Institute is used, which describes the boundaries of low-latitude zone I and high-latitude zone II of auroral diffuse precipitation. The longitudinal variations of the precipitation boundaries are corrected using the DMSP satellite data. The problem of separating the troughs becomes more complicated with the passage of local time, because the main ionospheric trough is more strongly displaced to the pole than the auroral oval; therefore, its area of existence begins to overlap the area of existence of the high-latitude trough. In order to identify and separate the main and ring troughs, all, even weak, geomagnetic disturbances for the observation period are analyzed in detail. The asymmetry of the Northern and Southern hemispheres is considered, and similar and different characteristics are identified. Therefore, a more complete and accurate pattern of the structure of the morning ionosphere is obtained.

Outdoor artificial light-at-night and cancer risk: an exposure assessment comparative study between DMSP, VIIRS and ISS satellite data

Outdoor artificial light-at-night and cancer risk: an exposure assessment comparative study between DMSP, VIIRS and ISS satellite data

Structure of the High-Latitude Noon Ionosphere of the Southern Hemisphere

The structure of the winter noon ionosphere of the southern hemisphere was studied. This structure includes the dayside cusp, associated high-latitude ionospheric trough (HLT), main ionospheric trough (MIT), electron density (Ne) peak at latitudes about 70°, mid-latitude ring ionospheric trough (RIT), and low-latitude quasi-trough. Data from the CHAMP satellite in the southern hemisphere for quiet geomagnetic conditions under high solar activity were selected for analysis. The DMSP satellite data and a model of auroral diffuse precipitation were also used. This model represents two zones of auroral diffuse precipitation on the equatorward and poleward edges of the auroral oval. It is shown that the situation in the winter noon ionosphere of the southern hemisphere depends cardinally on longitude. At sunlit longitudes, only the HLT is observed, and MIT is formed in the shadow region. At intermediate longitudes, both troughs can be observed and, therefore, there is a problem of their separation. The positions of all structures of the ionosphere depend on the longitude; in particular, the positions of the daytime MIT are changed by 6°−7°. At latitudes of the dayside cusp, both the peak and the minimum of Ne can be observed. A high and narrow peak of Ne is regularly recorded in the CHAMP data at latitudes of the equatorward zone of diffuse precipitation (68°−72°). In the shadow region, this peak forms the MIT poleward wall, and at sunlit longitudes a quasi-trough equatorward of this peak is sometimes observed. The RIT is rarely formed during the day, only at the American and Atlantic longitudes.

НАБЛЮДЕНИЕ БЫСТРЫХ СУБАВРОРАЛЬНЫХ ДРЕЙФОВ ИОНОСФЕРНОЙ ПЛАЗМЫ ПО ДАННЫМ ЯКУТСКОЙ МЕРИДИОНАЛЬНОЙ ЦЕПОЧКИ СТАНЦИЙ

Using long-term data from Yakut meridional chain of Yakutsk — Zhigansk — Batagay — Tixie ionospheric stations, we study ionospheric signatures of fast subauroral ion drift. Sharp drops or “falls” of critical frequencies (FCF) of the ionospheric F layer are shown to be one of the main signatures of the development of fast subauroral ion drifts near or at the zenith of the observation station. Comparison between long-term ground-based and satellite measurements indicates that there is good agreement between seasonal variation in the probability of occurrence of FCF derived from ground-based data and subauroral ion drifts derived from DMSP satellite data. Such a coincidence implies that both satellite and ground-based measurement methods register the same phenomenon in the boundary layers of the plasmasphere, namely, the appearance and development of electric fields of magnetospheric origin. The local time for recording of falls of the critical frequency derived from the ground-based data is shown to closely coincide with the appearance time of subauroral polarization streams of plasma according to satellite data. We can therefore conclude that most of the observed FCFs derived from ground-based data refer to intense storms.

FAST SUBAURORAL DRIFTS OF IONOSPHERE PLASMA ACCORDING TO DATA FROM YAKUT MERIDIONAL CHAIN OF STATIONS

Using long-term data from Yakut meridional chain of Yakutsk — Zhigansk — Batagay — Tixie ionospheric stations, we study ionospheric signatures of fast subauroral ion drift. Sharp drops or “falls” of critical frequencies (FCF) of the ionospheric F layer are shown to be one of the main signatures of the development of fast subauroral ion drifts near or at the zenith of the observation station. Comparison between long-term ground-based and satellite measurements indicates that there is good agreement between seasonal variation in the probability of occurrence of FCF derived from ground-based data and subauroral ion drifts derived from DMSP satellite data. Such a coincidence implies that both satellite and ground-based measurement methods register the same phenomenon in the boundary layers of the plasmasphere, namely, the appearance and development of electric fields of magnetospheric origin. The local time for recording of falls of the critical frequency derived from the ground-based data is shown to closely coincide with the appearance time of subauroral polarization streams of plasma according to satellite data. We can therefore conclude that most of the observed FCFs derived from ground-based data refer to intense storms.

First Joint Observations of Radio Aurora by the VHF and HF Radars of the ISTP SB RAS

Two modern radars for diagnosis of the ionosphere by the radio-wave backscattering method, namely, the Irkutsk incoherent scatter radar at VHF (IISR, 154–162 MHz) and the Ekaterinburg coherent radar at HF (EKB, 8–20 MHz) are operated at the Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS). The paper analyzes the results of joint observations of strong scattering (radio aurora) on June 8, 2015. To determine the geographical position of the radio aurora, we developed original methods that take into account both the features of the radio-wave propagation and the features of the radar antenna systems. It is shown that there are areas where the spatial position of the HF and VHF radio aurora can coincide. This permits using the radars as a single complex for diagnosis of the characteristics of small-scale high-latitude irregularities in the ionospheric E and F layers. A comparative analysis of the characteristics and temporal dynamics of the radio-aurora region in the HF and VHF ranges is performed. Using the DMSP satellite data, it has been shown that the radio aurora dynamics during this experiment with the EKB radar can be related with the spatial dynamics of the localized area with high electric field, which moves from high to equatorial latitudes. It is found that due to the broader field of view, radio aurora at the HF radar was stably observed 6–12 min earlier than at the VHF radar. This permits using the EKB radar data for prediction of the radio-aurora detection by the IISR radar.

Outdoor light and breast cancer incidence: a comparative analysis of DMSP and VIIRS-DNB satellite data

ABSTRACTSeveral population-level studies explored the association between breast cancer (BC) incidence and artificial light-at-night (ALAN), and found higher BC rates in more lit areas. Most of these studies used ALAN satellite data, available from the United States Defence Meteorological Satellite Program (US-DMSP), while, in recent years, higher-resolution ALAN data sources, such as Visible Infrared Imaging Radiometer Suite Day-Night Band (VIIRS-DNB), have become available. The present study aims to determine whether the use of different ALAN data sources may affect the BC–ALAN association. As the test case, we use data on BC incidence rates in women residing in the Greater Haifa Metropolitan Area (GHMA; Israel), matching them with US-DMSP and VIIRS-DNB data on ALAN intensities, and controlling for several potential confounders, including age, fertility, and socio-economic status (SES). Both ordinary least squares (OLS) and spatial dependency models were used in the analysis. ALAN emerged as a stronger predictor of BC rates in models based on better-resolution VIIRS-DNB estimates (t > 6.035; p < 0.01) than in models based on coarser US-DMSP data (t < 4.196; p < 0.01).

Exploring the efficacy of different electric field models in driving a model of the plasmasphere

AbstractThe dynamics of the plasmasphere are strongly controlled by the inner magnetospheric electric field. In order to capture realistically the erosion of the nightside plasmapause and the formation of the drainage plume in a model of the plasmasphere, the electric field must be accurate. This study investigates how well five different electric field models drive the Dynamic Global Core Plasma Model during eight storm periods. The five electric field models are the Volland‐Stern analytic formula with Maynard‐Chen Kpdependence, two versions of the Weimer statistical models (96 and 05), and two versions of the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) technique using magnetometer and DMSP satellite data. Manually extracted plasmapause locations from images taken by the EUV instrument on the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) satellite, as described by Goldstein et al. (2005), were compared to the simulation results throughout the main phase of the eight events. Three methods of calculating the plasmapause were employed to determine the best fit to EUV data, using the maximum gradient, a constant density contour (fit method), and the location in which the modeled density fell significantly below the specified saturation density for the given radial position (saturation method). It was found that the simulations driven by the Weimer (1996) model produced the best fit overall and that the fit and saturation methods worked best for matching the model results to the observations.

Auroral precipitation dynamics during strong magnetic storms

The dynamics of the auroral precipitation boundaries in the daytime (0900–1200 MLT) and nighttime (2100–2400 MLT) sectors during two strong magnetic storms of February 8–9, 1986, and March 13–14, 1989, with a Dst value at a maximum of approximately −300 and −600 nT, respectively, are studied using the DMSP satellite data. It is shown that, during the main phase of a storm, a shift to lower latitudes of the poleward and equator ward boundaries of the daytime precipitation is observed. In the nighttime sector, the equatorward boundary of the precipitation also shifts to lower latitudes, whereas the position of the poleward boundary depends weakly on the magnetic activity level even in the periods of very strong magnetic disturbances. The increase in the polar cap area occurs mainly due to the equatorward shift of the daytime precipitation. A high correlation degree between the equatorward shift of the poleward boundary of the daytime precipitation and the position of the equatorward boundary of the precipitation at the nighttime side of the Earth is demonstrated. The analysis of the events shows that (1) the magnetic activity level in the nighttime sector of the auroral zone influences considerably the position of the daytime precipitation boundaries during magnetic storms and that (2) the ring current inputs considerably into the value of the Dst variations.

The dynamics of the auroral oval and ionospheric trough boundaries according to data from the DMSP satellites and ground-based ionosonde network

This paper presents the results of a combined analysis of the experimental data of vertical- and oblique-incidence ionospheric sounding in the northeastern region of Russia and of the DMSP satellite data from 1999 to 2003. During geomagnetic disturbances period on ionograms we can see anomalous diffuse signals, which propagates outside great circle arc. The joint data analysis permits to suggest that the appearance of additional anomalous signals is connected with radio waves refraction in auroral oval and main ionospheric trough areas and with scattering on small-scale field-aligned irregularities close to auroral oval equatorial boundary in the region of electron diffuse precipitation. The basic attention is given to diagnostics of main ionospheric trough boundary and auroral oval zones position during geomagnetic disturbances periods.

Statistics of a parallel Poynting vector in the auroral zone as a function of altitude using Polar EFI and MFE data and Astrid-2 EMMA data

Abstract. We study the wave-related (AC) and static (DC) parallel Poynting vector (Poynting energy flux) as a function of altitude in auroral field lines using Polar EFI and MFE data. The study is statistical and contains 5 years of data in the altitude range 5000–30000 km. We verify the low altitude part of the results by comparison with earlier Astrid-2 EMMA Poynting vector statistics at 1000 km altitude. The EMMA data are also used to statistically compensate the Polar results for the missing zonal electric field component. We compare the Poynting vector with previous statistical DMSP satellite data concerning the electron precipitation power. We find that the AC Poynting vector (Alfvén-wave related Poynting vector) is statistically not sufficient to power auroral electron precipitation, although it may, for Kp&gt;2, power 25–50% of it. The statistical AC Poynting vector also has a stepwise transition at R=4 RE, so that its amplitude increases with increasing altitude. We suggest that this corresponds to Alfvén waves being in Landau resonance with electrons, so that wave-induced electron acceleration takes place at this altitude range, which was earlier named the Alfvén Resonosphere (ARS). The DC Poynting vector is ~3 times larger than electron precipitation and corresponds mainly to ionospheric Joule heating. In the morning sector (02:00–06:00 MLT) we find that the DC Poynting vector has a nontrivial altitude profile such that it decreases by a factor of ~2 when moving upward from 3 to 4 RE radial distance. In other nightside MLT sectors the altitude profile is more uniform. The morning sector nontrivial altitude profile may be due to divergence of the perpendicular Poynting vector field at R=3–4 RE. Keywords. Magnetospheric physics (Auroral phenomena; Magnetosphere-ionosphere interactions) – Space plasma physics (Wave-particle interactions)

Comparison of the characteristic energy of precipitating electrons derived from ground-based and DMSP satellite data

Abstract. Energy maps are important for ionosphere-magnetosphere coupling studies, because quantitative determination of field-aligned currents requires knowledge of the conductances and their spatial gradients. By combining imaging riometer absorption and all-sky auroral optical data it is possible to produce high temporal and spatial resolution maps of the Maxwellian characteristic energy of precipitating electrons within a 240240 common field of view. These data have been calibrated by inverting EISCAT electron density profiles into equivalent energy spectra. In this paper energy maps produced by ground-based instruments (optical and riometer) are compared with DMSP satellite data during geomagnetic conjunctions. For the period 1995-2002, twelve satellite passes over the ground-based instruments' field of view for the cloud-free conditions have been considered. Four of the satellite conjunctions occurred during moderate geomagnetic, steady-state conditions and without any ion precipitation. In these cases with Maxwellian satellite spectra, there is 71% agreement between the characteristic energies derived from the satellite and the ground-based energy map method.

Self-consistent modeling of the large-scale distortions in the geomagnetic field during the 24–27 September 1998 major magnetic storm

A new self‐consistent version of a time‐dependent magnetospheric paraboloid model is presented and tested on the 24–27 September 1998 magnetic storm interval (minimum Dst = −207 nT). The model uses DMSP satellite data to identify the location of the inner boundary of the magnetotail current sheet and the magnetic flux in the lobes and their variations with time. These inputs plus upstream solar wind dynamic pressure and IMF Bz values are used to iteratively model the Earth's field during the storm. Several interesting results with important consequences are obtained: (1) the model tail field strength at the Earth's surface (DT = −134 nT) is a significant fraction of the ring current value (DR = −167 nT); (2) the movement of the tail current sheet inward to L = 3.5–4.0 at storm maximum is consistent with geosynchronous magnetic field data; (3) at the Earth's surface the Chapman‐Ferraro magnetopause current field (DCF = 117 nT) is almost equal at storm maximum to the value from the tail current, thus the fields from the two systems nearly cancel; (4) the magnetic flux from the polar cap in the course of the magnetic storm main phase approximately doubles in comparison with the magneto‐quiet interval just before the storm onset; this fact shows that the driven processes prevail over dissipation processes throughout the storm main phase; (5) the large‐scale internal currents in the magnetosphere (ring current, field‐aligned currents, and magnetotail current) have significant influence on the shape and size of the magnetosphere; the location of the magnetopause subsolar point is different from that obtained by extrapolation of empirical results taken during high geomagnetic activity intervals and from magnetospheric models that do not include feedback from internal magnetospheric currents.

A comparison of polar cap ionospheric velocity determined from a digital ionosonde model and the DICM and IZMEM/DMSP electric potential models

Digisonde Portable Sounder 4 (DPS-4) ionospheric F-region drift measurements at the polar cap station Casey (110.5°E, 66.3°S geographic, 80.8°S corrected geomagnetic), Antarctica were used to derive the Casey 1997 (C97) regression model of Smith [Ionospheric F-region plasma convection at Casey – a southern polar cap station. PhD Thesis. La Trobe University, Australia, 1998]. F-region ionospheric convection velocities derived from C97 are compared with convection velocities derived from the application of E × B /B 2 at the geomagnetic latitude of Casey to the relatively new DICM and IZMEM/DMSP fully parameterized electric potential convection models of Papitashvili and Rich [J. Geophys. Res. 107 (A8) 1198, 2002]. Where the DICM model was constructed from satellite F-region ion drift observations from DMSP satellite data at 840 km, and the IZMEM/DMSP model was constructed using ground-magnetometer measurements and calibrated against DMSP ion data. A comparison between C97 and the new DICM and IZMEM/DMSP models was undertaken as a function of dipole tilt angle or season and for a range of IMF parameters. The initial results of the comparison between these experimental models for estimating F-region ionospheric convection drift velocities will be presented.

The first World Atlas of the artificial night sky brightness

We present the first World Atlas of the zenith artificial night sky brightness at sea level. Based on radiance calibrated high resolution DMSP satellite data and on accurate modelling of light propagation in the atmosphere, it provides a nearly global picture of how mankind is proceeding to envelope itself in a luminous fog. Comparing the Atlas with the U.S. Department of Energy (DOE) population density database we determined the fraction of population who are living under a sky of given brightness. About two thirds of the World population and 99% of the population in US (excluding Alaska and Hawaii) and EU live in areas where the night sky is above the threshold set for polluted status. Assuming average eye functionality, about one fifth of the World population, more than two thirds of the US population and more than one half of the EU population have already lost naked eye visibility of the Milky Way. Finally, about one tenth of the World population, more than 40% of the US population and one sixth of the EU population no longer view the heavens with the eye adapted to night vision because the sky brightness.

Naked-eye star visibility and limiting magnitude mapped from DMSP-OLS satellite data

We extend the method introduced by Cinzano et al. to map the artificial sky brightness in large territories from DMSP satellite data, in order to map the naked-eye star visibility and telescopic limiting magnitudes. For these purposes we take into account the altitude of each land area from GTOPO30 world elevation data, the natural sky brightness in the chosen sky direction, based on Garstang modelling, the eye capability with the naked eye or a telescope, based on the Schaefer and Garstang approach, and the stellar extinction in the visual photometric band. For near-zenith sky directions we also take into account screening by terrain elevation. Maps of naked-eye star visibility and telescopic limiting magnitudes are useful for quantifying the capability of the population to perceive our Universe, evaluating the future evolution, making cross-correlations with statistical parameters, and recognizing areas where astronomical observations or popularization can still acceptably be made. We present, as an application, maps of naked-eye star visibility and total sky brightness in the V band in Europe at the zenith with a resolution of approximately 1 km.

SuperDARN studies of the ionospheric convection response to a northward turning of the interplanetary magnetic field

Abstract. The response of the dayside ionospheric flow to a sharp change in the direction of the interplanetary magnetic field (IMF) measured by the WIND spacecraft from negative Bz and positive By, to positive Bz and small By, has been studied using SuperDARN radar, DMSP satellite, and ground magnetometer data. In response to the IMF change, the flow underwent a transition from a distorted twin-cell flow involving antisunward flow over the polar cap, to a multi-cell flow involving a region of sunward flow at high latitudes near noon. The radar data have been studied at the highest time resolution available (~2 min) to determine how this transition took place. It is found that the dayside flow responded promptly to the change in the IMF, with changes in radar and magnetic data starting within a few minutes of the estimated time at which the effects could first have reached the dayside ionosphere. The data also indicate that sunward flows appeared promptly at the start of the flow change (within ~2 min), localised initially in a small region near noon at the equatorward edge of the radar backscatter band. Subsequently the region occupied by these flows expanded rapidly east-west and poleward, over intervals of ~7 and ~14 min respectively, to cover a region at least 2 h wide in local time and 5° in latitude, before rapid evolution ceased in the noon sector. In the lower latitude dusk sector the evolution extended for a further ~6 min before quasi-steady conditions again prevailed within the field-of-view. Overall, these observations are shown to be in close conformity with expectations based on prior theoretical discussion, except for the very prompt appearance of sunward flows after the onset of the flow change.Key words. Ionosphere (Auroral ionosphere) · Magnetospheric physics (Magnetopause · cusp · and boundary layers; Magnetosphere · ionosphere interaction)

SuperDARN studies of the ionospheric convection response to a northward turning of the interplanetary magnetic field

The response of the dayside ionospheric flow to a sharp change in the direction of the interplanetary magnetic field (IMF) measured by the WIND spacecraft from negative Bz and positive By, to positive Bz and small By, has been studied using SuperDARN radar, DMSP satellite, and ground magnetometer data. In response to the IMF change, the flow underwent a transition from a distorted twin-cell flow involving antisunward flow over the polar cap, to a multi-cell flow involving a region of sunward flow at high latitudes near noon. The radar data have been studied at the highest time resolution available (~2 min) to determine how this transition took place. It is found that the dayside flow responded promptly to the change in the IMF, with changes in radar and magnetic data starting within a few minutes of the estimated time at which the effects could first have reached the dayside ionosphere. The data also indicate that sunward flows appeared promptly at the start of the flow change (within ~2 min), localised initially in a small region near noon at the equatorward edge of the radar backscatter band. Subsequently the region occupied by these flows expanded rapidly east-west and poleward, over intervals of ~7 and ~14 min respectively, to cover a region at least 2 h wide in local time and 5° in latitude, before rapid evolution ceased in the noon sector. In the lower latitude dusk sector the evolution extended for a further ~6 min before quasi-steady conditions again prevailed within the field-of-view. Overall, these observations are shown to be in close conformity with expectations based on prior theoretical discussion, except for the very prompt appearance of sunward flows after the onset of the flow change.Key words. Ionosphere (Auroral ionosphere) · Magnetospheric physics (Magnetopause · cusp · and boundary layers; Magnetosphere · ionosphere interaction)

Precipitation efficiency of trade wind clouds over the north central tropical Pacific Ocean

The magnitude and distribution of precipitation within trade wind clouds east of the Hawaiian Islands and the efficiency of these clouds in returning water evaporated from the ocean surface back to the ocean through precipitation are examined using highresolution visible and infrared DMSP satellite data and 5‐cm wavelength radar data collected during the 1990 Hawaiian Rainband Project. The analyses indicate that on average, precipitation rates greater than 0.1 mm h−1 occur over about 11% of the area occupied by trade wind clouds at any given time, while about 1.5% of the cloudy areas had rainfall rates which exceeded 1.0 mm h−1. None of the clouds in the sample had precipitation rates exceeding 10.0 mm h−1. The average precipitation rate was 1.1 mm d−1. An estimate of the precipitation efficiency of the trade wind clouds, made by comparing the latent heat input into the atmosphere due to precipitation with the ocean surface latent heat flux, suggests that clouds in the trade wind regime are no more than 20–30% efficient in returning evaporated water vapor to the ocean through precipitation processes.

DMSP calibration

Although DMSP satellite data are widely used, there has been no reliable absolute calibration. Coordinated data with ground‐based photometers allow a calibration curve of film density versus 4728 N2+ intensity to be derived. The DMSP satellites (5C series) record airglow and can detect auroral forms of intensities ≥50 R of 4278 N2+. It is estimated that the 5D series satellites are capable of detecting auroras with ∼25 R of 4278 N2+.