Effects Of Storms Research Articles

Comparison of Empirical and Theoretical Models of the Thermospheric Density Enhancement During the 3–4 February 2022 Geomagnetic Storm

AbstractOn 3 February 2022, at 18:13 UTC, SpaceX launched and a short time later deployed 49 Starlink satellites at an orbit altitude between 210 and 320 km. The satellites were meant to be further raised to 550 km. However, the deployment took place during the main phase of a moderate geomagnetic storm, and another moderate storm occurred on the next day. The resulting increase in atmospheric drag led to 38 out of the 49 satellites reentering the atmosphere in the following days. In this work, we use both observations and simulations to perform a detailed investigation of the thermospheric conditions during this storm. Observations at higher altitudes, by Swarm‐A (∼438 km, 09/21 Local Time [LT]) and the Gravity Recovery and Climate Experiment Follow‐On (∼505 km, 06/18 LT) missions show that during the main phase of the storms the neutral mass density increased by 110% and 120%, respectively. The storm‐time enhancement extended to middle and low latitudes and was stronger in the northern hemisphere. To further investigate the thermospheric variations, we used six empirical and first‐principle numerical models. We found the models captured the upper and lower thermosphere changes, however, their simulated density enhancements differ by up to 70%. Further, the models showed that at the low orbital altitudes of the Starlink satellites (i.e., 200–300 km) the global averaged storm‐time density enhancement reached up to ∼35%–60%. Although such storm effects are far from the largest, they seem to be responsible for the reentry of the 38 satellites.

Effect of strong geomagnetic storms and their association with solar wind plasma temperature and IMF during solar cycles 23 and 24.

Strong interaction of CMEs with Earth’s environment causes serious space weather effect through the coupled magnetosphere system. A geomagnetic storm is a global disruption of the earth’s magnetic field, and usually occurs in response to abnormal conditions in the IMF and solar wind. In this paper we present the consequences on interplanetary causes of strong geomagnetic storms (Dst ≤ -200nT), that occurred during solar cycle 23 and 24. It was found that the positive correlation with correlation coefficient (0.46) between the magnitude of strong geomagnetic storm and magnitude of solar wind plasma temperature, (0.54) between the magnitude of strong geomagnetic storm and magnitude of solar wind plasma velocity, (.58) between the magnitude of strong geomagnetic storm and magnitude of southward component of interplanetary magnetic field (IMF Bz) and (0.54) between strong geomagnetic storm and magnitude of interplanetary magnetic field (IMF Btotal).The correlation between magnitude of strong geomagnetic storm and magnitude of interplanetary magnetic field (with positive correlation coefficient 0.58) is higher, as compared with magnitude of strong geomagnetic storm and magnitude of solar wind plasma temperature (0.46). It has been verified that strong geomagnetic storm intensity is correlated well with the interplanetary magnetic field IMF (Btotal and Bz) better than with its solar parameters.

Impact of ICME- and SIR/CIR-Driven Geomagnetic Storms on the Ionosphere over Hungary

We investigate the differences between the effects of geomagnetic storms due to Interplanetary Coronal Mass Ejections (ICME) and due to Stream Interaction Regions or Corotating Interaction Regions (SIR/CIR) on the ionospheric F2-layer during the maximum of solar cycle 24. We have created a unique list of the ICME- and SIR/CIR-driven geomagnetic storm events for the time interval between November 2012 and October 2014. Finally, 42 clear ICME and 34 clear SIR/CIR events were selected for this analysis. The individual geomagnetic storm periods were grouped by seasons, time of day, and local time of Dstmin and were analyzed using three different methods: linear correlation analysis using 4-h averages of foF2 parameters and the geomagnetic indices (1st), daily variation of deltafoF2 (2nd), and 3D plotting: geomagnetic indices vs. time vs. deltafoF2 (3rd). The main phase day of the ICME- and SIR/CIR-induced geomagnetic storms was our main focus. We used manually evaluated ionospheric foF2 parameters measured at the Sopron ionosonde station and the geomagnetic indices (Kp, Dst, and AE) for this analysis. We have found that in most cases, the variation of the Dst index is the best indicator of the impact caused in the F2 layer. We conclude as well that the representation of the data by the third method gives a better description of the ICME and SIR/CIR-triggered storm behavior. In addition, our investigation shows that the SIR/CIR-related perturbations can be predicted with greater accuracy with the second method.

Resilience to extreme weather events and local financial structure of prefecture-level cities in China

We study the local economic impacts of extreme weather events and the role of local finance in economic resilience. We use data on the physical intensities of extreme wind and precipitation events for 284 prefecture-level cities in China between 2004 and 2013. We estimate impulse response functions using a bias-corrected method of moments estimator to capture the dynamic responses of affected cities up to 5 years after such events. We find that extreme precipitation events depress the growth of local GDP per capita for multiple years, while the negative effects of storms vanish after the first year. We then use this model to measure the economic resilience of cities to extreme weather events. Regressions of economic resilience on indicators of the local financial structure suggest that cities with higher levels of debt are less resilient. Moreover, the presence of state-owned commercial banks appears to be instrumental to regional economic resilience. As extreme weather events are expected to become more frequent and severe due to climate change, our results inform the emerging debate about regional economic resilience to weather-related shocks.

Changes in the mechanism of the South-Asian summer monsoon onset propagation induced by the pre-monsoon aerosol dust storm

A modeling effort is considered to understand the effect of dust aerosol storms in the Indian summer monsoon (ISM) onset propagation over the Indian subcontinent. The study found how the dust aerosol loading during the pre-monsoon period over the Indian subcontinent positively impacts the advancing ISM onset. The heavy loading of dust aerosol from middle east Asia to the northwest (NW) Indian region boosts the temperature gradient over the mid-troposphere. This sudden rise in the mid-tropospheric atmospheric temperature triggers the low-pressure belt over the monsoon trough. It amplifies the Elevated Heat Pump mechanism and loads enough dust for the dust storm over north India. The formation of the monsoon trough over the Indo-Gangetic Plain (IGP) pulls the moisture-loaded wind towards the Indian subcontinent and the IGP, followed by the onset of monsoon over Kerala within a week. Due to this storm, the intense heat gradient in the troposphere also induces the monsoon propagation and the monsoon advancement from Kerala to BoB within a short time. However, it makes up for the naturally delayed monsoon on time. Plain language summaryStudy shows how the pre-monsoon dust storm modulates the Indian summer monsoon (ISM) propagation over the Indian region. The onset of the monsoon was delayed in a particular year, and the pre-monsoon dust storm over northwest India changed the regular monsoon mechanism and generated an entirely different mechanism. The elevated heat pump theory applies that pushes the monsoon advancement faster than usual. A dust storm over north India causes a sudden rise in the mid-tropospheric temperature gradient and more rapid monsoon advancement than usual.

Long-lasting, deep effect of Saturn's giant storms.

Planetary-scale giant storms erupt on Saturn quasiperiodically. There have been at least six recorded occurrences of past eruptions, and the most recent one was in 2010, with its whole life span captured by the Cassini mission. In 2015, we used the Very Large Array to probe the deep response of Saturn's troposphere to the giant storms. In addition to the remnant effect of the storm in 2010, we have found long-lasting signatures of all mid-latitude giant storms, a mixture of equatorial storms up to hundreds of years old, and potentially an unreported older storm at 70°N. We derive an ammonia anomaly map that shows an extended meridional migration of the storm's aftermath and vertical transport of ammonia vapor by storm dynamics. Intriguingly, the last storm in 2010 splits into two distinct components that propagate in opposite meridional directions, leaving a gap at 43°N planetographic latitude.

WPŁYW INFEKCJI SARS-CoV-2 NA FUNKCJĘ TARCZYCY – PATOMECHANIZM I IMPLIKACJE KLINICZNE

The SARS-CoV-2 virus is the pathogenic agent of the COVID-19 disease, which pandemic had caused 6.8 million deaths worldwide by February 2023. In the course of the disease, involvement of the thyroid gland is observed. The pathomechanism of damage to the thyroid gland is bidirectional – direct cytotoxicity of the virus and the indirect effect of a cytokine storm. Circulating pro-inflammatory cytokines lead to deiodinase activity dysregulation, resulting in changes in plasma concentrations of TSH, fT3, and fT4. These hormone abnormalities are observed in about 16% of patients during COVID-19 and may also result from the treatment itself – systemic corticosteroids. Dysregulation of the immune system also leads to autoinflammatory thyroid diseases. It seems crucial to monitor thyroid hormones to detect subclinical forms of thyroiditis early. This paper presents the prevalence and potential pathomechanism of thyroid disorders observed during SARS-CoV-2 infection – subacute thyroiditis, low T3 syndrome, Graves-Basedow disease, and Hashimoto’s disease.

Mortality Rate and Acute Kidney Injury Prevalence Reduction in COVID-19 Critical Patients Treated with Hemoperfusion.

Coronavirus disease 2019 (COVID-19) induces organic damage mainly through the patient's immune overreaction. Hemoperfusion (HPF) can remove inflammatory cytokines and can reduce the negative effects of cytokine storm in COVID-19. We compared the mortality rate, inflammatory response, and acute kidney injury (AKI) prevalence among patients suffering from respiratory insufficiency secondary to COVID-19 treated with and without HPF with HA330 cartridge. Mortality rate, serum creatinine, and ferritin values were compared between patients suffering from respiratory insufficiency secondary to COVID-19 who received conventional treatment and another group of patients who additionally received four sessions of HPF with HA330. Of 116 patients suffering from acute respiratory insufficiency secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), one group (n: 84) received support treatment and the other group (n: 32) additionally received HPF with HA330 cartridge. Both groups had no renal disease and similar age and comorbidities at admission, except for obesity and mechanical ventilation requirement, which were significantly higher in the HPF group. Mortality rate (61% vs. 31%, P: 0.008), serum creatinine (1.4 vs. 0.5 mg/dl, P < 0.001), and post-HPF serum ferritin (2868 vs. 1675, P < 0.001) were significantly lower in the HPF group. Mortality rate, serum ferritin, and AKI were significantly reduced in critical COVID-19 patients who received HPF with HA330 cartridge than in those who did not receive it. These results were obtained despite the HPF group risk factors, such as obesity and mechanical ventilation, worsening its prognosis.

DCB estimation and analysis using the single receiver GPS/GLONASS observations under various seasons and geomagnetic activities

Global Navigation Satellite Systems (GNSS) have many applications in surveying, geodesy, and everyday life, so the accuracy of observations is very important. To have accurate results, many errors should be corrected, including ionospheric errors. Estimating the Differential Code Bias (DCB) and Total Electron Content (TEC) is essential to reduce ionospheric errors. This study's main aim is to determine how the combination of GPS (Global Positioning System) and GLONASS (GLObal NAvigation Satellite System) observations affect the estimation of DCB of satellites (SDCB) and receivers (RDCB) under the effects of geomagnetic storms and seasonal changes. The MATLAB-based software GR_DCB (GPS and GLONASS DCB estimation) was developed to estimate the SDCB and RDCB based on GPS and GLONASS observations. Theresults were tested using data from the International GNSS Service (IGS) network from nine stations and compared to previous studies to assess the effectiveness of the developed code. The findings are consistent with IGS products and more precise than previous studies that relied solely on GPS observations. An analysis of the effects of the geomagnetic storm on DCB variance is considered for June 22–23, 2015. During the geomagnetic storm, all GPS and GLONASS stations exhibited a fall in RDCB, led by a modest increase in some stations. The SDCB had no observed change on storm days compared with quiet days. The seasonal change affected GPS and GLONASS stations RDCB. Winter, which has the highest RDCB mean values, is also the season when a deviation in RDCB is the greatest. Autumn and Summer had the lowest dispersion in RDCB over the season and the lowest RDCB values.

Presentation and validation of the internal charging risk forecast in the PAGER framework

The Prediction of Adverse effects of Geomagnetic storms and Energetic Radiation project (PAGER) aims to provide a framework for space weather and related effects forecasts. One of the innovative concepts is to plug, downstream of the environment prediction models, an automatized chain evaluating both surface and internal charging to forecast a charging risk evaluation for spacecraft on GEO and MEO orbits.The evaluation of the internal charging risk induced by electrons of the radiation belts with an energy above ∼0.5 MeV, is carried out throughout an innovating approach, combining different charging models, downstream the environmental ones. The space weather forecast is provided by a simulation of the radiation belt performed with VERB-3D. Downstream, the charging analysis is mainly performed using SPIS-IC, the internal charging branch of the open-source SPIS software (Spacecraft Plasma Interaction Software). SPIS-IC requires the prior computation of the source terms of space charge and dose rates resulting from the transport of primary electrons through the spacecraft structure. This is done beforehand using a 3D direct Monte-Carlo approach. In addition, a simple and fast internal charging 1D code, ICOne has been developed and is also used to evaluate the internal charging risk, based on a semi-empirical deposition rule.The internal charging modeling chain is used to carry out on one hand an evaluation of the electrical risk on a satellite in MEO orbit surrounded by an environment simulated by the VERB-3D Fokker-Plank code, and on the other hand, to reproduce measurements of a charging event of GIOVE-A.

Report on current status of mangrove forests in India

AbstractThere are positive effects on climate, water availability, and temperature that may be attributed to the presence of mangrove forests. In addition, mangroves provide natural infrastructure and protection to human communities that are located nearby by preventing erosion and absorbing the effects of storm surges caused by large weather events such as hurricanes. Regrettably, the disappearance of mangroves harms the ecology and the environment's viability. Using secondary sources and a descriptive approach to study, this article investigates the impact that the destruction of mangrove forests in India has had on the surrounding ecosystem. The research findings indicate that India's most significant contributors to environmental destruction are development activities and other reasons. Deforestation may lead to many negative outcomes, including changes in climate, a reduction in biodiversity, the destruction of habitat, and armed conflict.

Regional ionospheric TEC modeling during geomagnetic storm in August 2021- data fusion using multi-instrument observations

Regional ionospheric Total Electron Content (TEC) models are most significant to investigate the variability of ionosphere during all-weather conditions. Since the ground-based TEC measurements are not available in oceanic and polar regions, space-based observations are incorporated to increase the positional accuracy and reliability of Global Ionospheric TEC Maps (GIMs). Therefore, data fusion techniques are necessary to enhance the prediction capability of regional ionospheric models by considering multi-source data. In view of this, an attempt is made to investigate Equatorial Ionization Anomaly (EIA) structures in low-latitudinal Indian region using multi-instrument data. Data observations from background model CODEGIM, available International GNSS Service (IGS) stations in India, GNSS receivers at KLEF and Tripura stations, FORMOSAT/COSMIC radio occultation and SWARM during geomagnetic storm period August 26–28, 2021 are used for the study. Spherical Harmonics Function (SHF) of order 4 is employed along with Weighted Least Squares analysis (WLS), where separate weight constraint is computed for each data source. TEC maps of spatial resolution 5° x 5° and temporal resolution of 1 h are generated to illustrate the dynamic behavior of ionosphere. The standard deviation for 3 days is obtained as 0.42, 0.61 and 1.43 TECU respectively. TEC depletions and enhancements are observed on August 27 and 28, with mean values of 12.74 and 15.27 TECU respectively, demonstrating negative and positive storm effects.

Coastal morphodynamic emulator for early warning short-term forecasts

The use of numerical models to anticipate the effects of floods and storms in coastal regions is essential to mitigate the damages of these natural disasters. However, local studies require high spatial and temporal resolution numerical models, limiting their use due to the involved high computational costs. This constraint becomes even more critical when these models are used for real-time monitoring and warning systems. Therefore, the objective of this paper was to reduce the computational time of coastal morphodynamic models simulations by implementing a deep learning emulator. The emulator performance was evaluated using different scenarios run with the XBeach software, which considered different grid resolutions and the effects of a storm event in the morphodynamic patterns around a breakwater and a groin. The morphodynamic simulation time was reduced by 23%, and it was identified that the major restriction to reducing the computational cost was the hydrodynamic numerical model simulation.

The Effects of a Small Geomagnetic Storm on Earth's Thermosphere and Ionosphere: ICON Observations of the 25 January 2021 Disturbance

AbstractIsolated geomagnetic storms during solar minimum offer the opportunity to observe the effects of solar wind on Earth's atmosphere without interference from other background changes in the ionosphere‐thermosphere system. Here, we observe the effects of a minor storm on the ionosphere at middle and low latitudes, where disturbances in thermospheric winds and composition can produce storm‐time changes in ionospheric densities. Using data from the NASA Ionospheric Connection Explorer (ICON), we investigate the competing effects of composition changes and neutral wind disturbances in modifying the ionosphere during the 25 January 2021 storm. Large enhancements in plasma densities are seen across the dayside late on 25 January, associated with large changes in meridional winds and significant high‐latitude electric current enhancements as measured by the auroral electrojet index. At the same time, we find evidence of rapid transport of heated air from the southern auroral zone to the equator in the East‐Asian sector with the appearance of deeply reduced O/N2 in the morning sector and storm‐time northward winds prior to its appearance. We observe significant, rapid erosion of the high plasma densities in the sector where thermospheric disturbance appears over 5 hr of observation. The noon‐time plasma density enhancements are short‐lived and we observe no westward perturbation in the low‐middle latitude, dayside zonal winds over a 5‐day period including the storm. Thus, we attribute the ionospheric changes to prompt penetration and meridional wind forcing, while ruling out the presence of a storm‐time disturbance dynamo and its related ionospheric effects.

On the multi-scale dynamics and energy flow near reconnection regions in the magnetopause and magnetotail using the MMS, Cluster and THEMIS observations during the geomagnetic storm of 31 December 2015

Magnetic reconnection is a very important energy conversion process that plays a vital role in solar wind-magnetosphere coupling. This study presents a unique analysis of the coordinated observations from MMS, Cluster and THEMIS spacecraft during a geomagnetic storm on 31 December 2015. The analyses are aimed to understand the intricacies of the short-scale processes during 4 different short (20 min) encounters and a long duration (8 h) traversal of all the satellites covering the main and the recovery phase of the storm. The main results show that at the reconnection sites in the magnetotail, the FAC density is majorly contributed by the electrons moving anti-parallel to the magnetic field. Significantly, the FACs estimated from the Curlometer method and plasma (or local) method agree well and authenticate the interpretations. The majority of the electron population is found to shift towards the mid (0.2–2 keV) and high-energy (2–30 keV) range during the reconnection, wherein higher (∼one order more) ion and electron energy flux is observed under the effect of the intense storm compared to non-storm cases. The Hall electric field is found to be the major contributor to the total electric field during magnetic reconnection whereas, we observe the growing significance of the pressure divergence term during later phases of the storm. Longer duration (8-hour) continuous observations from the unique alignment of the four spacecrafts show a dominance of magnetic (plasma) properties over plasma (magnetic) properties in the magnetotail (magnetopause). The magnetotail (magnetopause) is found to be highly dynamic with higher (lower) levels of the electric and magnetic field, ion and electron temperature, and simultaneous lower (higher) levels of plasma density, energy flux, and FACs. The drastic enhancements of the plasma and field parameters happen in the sun-earth plane and during different crossings at the magnetopause and magnetotail. The simultaneous observations from magnetopause and magnetotail during a moderate geomagnetic storm indicate further needful coordinated investigations on the nature of reconnections on the day and night side and variations during the intense category of storms.

Validation of Ionospheric Modeled TEC in the Equatorial Ionosphere During the 2013 March and 2021 November Geomagnetic Storms

AbstractThis paper presents the validation of modeled total electron content (TEC) from 14 ionospheric models, including empirical, physics‐based, and data assimilation (DA) models, hosted by the NASA/NSF Community Coordinated Modeling Center (CCMC), NOAA Space Weather Prediction Center, and NASA Jet Propulsion Laboratory (JPL). This study aims to assess the current progress and capability of the CCMC‐hosted ionospheric models in capturing the storm time ionosphere during the low and moderate solar flux years. We focus on the low‐latitude ionosphere (i.e., ±40° in magnetic latitude) and compare the modeled TEC with the Madrigal TEC during the 2013 March and 2021 November storms. Multiple metrics are used to quantitatively assess the models' accuracy, precision, association, bias, and capability in capturing the TEC changes in response to the storms. The skill score based on the metric scores is further proposed to evaluate the overall performance of ionospheric models against the reference model (International Reference Ionosphere 2016; IRI‐2016). The results indicate that the DA model GLObal Total Electron Content and JPL Global Ionospheric Map models show good performance in modeling the TEC and reasonably reflect the storm time TEC changes spatially and temporally. The empirical models IRI‐2016 and 2020 show relatively good performance compared with the physics‐based models regarding the model‐data comparison; however, it is difficult to characterize the TEC changes caused by storms. The physics‐based models can simulate the storm effect in spatial and temporal TEC variations better than the empirical model. The performance of ionospheric models in capturing the storm time TEC anomaly is presented and discussed.

Dust Storm Effect and Climatological Factors on Cardiovascular and Cerebrovascular Respiratory Diseases: A Literature Review

Background &amp; Aims: Dust storms, which are considered natural occurrences, have harmed the global population’s health as a result of the broad increase in climate change. The most serious consequences of these alterations are cardiovascular, pulmonary, and cerebrovascular diseases. This review study focused on the effect of dust storms and climatic factors on mortality and morbidity in worldwide and assessed the prediction of these diseases based on changes in each of the meteorological factors and dust storms. Materials and Methods: For data collection, English literature was searched using keywords "dust storm" and "respiratory disorders" or "cardiovascular disease" or "cerebrovascular disease" in PubMed, Web of Science, and Scopus as databases, along with Google Scholar as engine search. The first step was to use statistics on the number of instances of cardiovascular, cerebrovascular, and respiratory diseases. The association between the occurrence of these diseases and variations in climatic factors underwent assessment. Results: Adverse repercussions could be noticed when dust storms were paired with changes in metrological parameters. More local information about the link of these diseases with dust storms and changes in metrological variables in the nation, as well as their capacity to anticipate them, is needed to prevent and reduce the health risk of these diseases. Conclusion: In areas prone to dust storms, the population will be prone to its effects and consequences. Thus, preventive measures are beneficial at the community level.

An investigation of the effects of sand and dust storms in the North East Sahara Desert on Turkish airports and PM10 values: 7 and 8 April, 2013 events.

Between April 7 and April 10, 2013, a cyclone with a value of 995hPa that developed in the central Mediterranean transported dust from the Sahara Desert towards Turkey. At 13 airports in Turkey, dust haze and widespread dust were seen during different occasions in this period and caused the observation of so-called "Blowing dust events." This cyclone blew dust towards the Cappadocia airport, and the prevailing visibility decreased to 3800m, making it the lowest value measured during the transition of this cyclone. In this study, Aviation Routine Weather Report (Metar) and Aviation Selected Special Weather Report (Speci) observations of airports in North Africa and Turkey were evaluated for the period between April 3 and April 11, 2013. With this cyclone the prevailing visibility at Benina Airport in Libya decreased to 50m on April 6, 2013. This study aims to evaluate long-distance dust transport's effects on meteorological visibility at airports in Turkey and examine the episodic changes of PM10 values measured by air quality monitoring stations. Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model outputs were used to determine the trajectories of long-distance dust particles. Powder red, green, and blue (RGB) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images, Cloud-Aerosol LIDAR Infrared Pathfinder Satellite Observations (CALIPSO) images, the Barcelona Supercomputing Center-Dust Regional Atmosphere Model (BSC-DREAM8b) outputs, and Global Forecast System (GFS) synoptic maps were used for analysis. In addition, PM10 values obtained from air quality monitoring stations were examined. According to the data obtained from the CALIPSO images, the dust concentration on the Eastern Mediterranean reaches up to 5km. The episodic values obtained from certain air quality measurement stations are Adana 701, Gaziantep 629, Karaman 900, Nevşehir 1343, and Yozgat 782µg/m3 on an hourly average.

OSL dating of coastal dunes on the southeastern coast of Hainan Island, China

Coastal dune sediments and landforms offer a unique opportunity to understand climate change and sea level change on the centennial-millennial time scale. However, there is a paucity of chronological studies on the effects of storms on the evolution of coastal dunes along the temperate coastline of China. In this study, optically stimulated luminescence (OSL) dating of sand dunes was conducted to investigate the process and mechanism of coastal dune evolution on the southeastern coast of Hainan Island, China. The results show that the coastal dune evolution experienced three rapid accumulation periods: 28-21 ka, 14-4 ka, and 3.0 ka-present. The three rapid accumulation periods correspond to the last glacial maximum, the late Pleistocene/early-mid Holocene, and the late Holocene climatic dry-cold period, respectively. Sea level change and the East Asian winter monsoon, in conjunction with the enhanced storminess, play a key role in driving the sand dune evolution on the south-eastern coast of Hainan Island. These findings are of great significance for regional planning and coastal defense schemes.

Ophthalmic Manifestations Among Patients Surviving COVID-19.

To identify ocular findings related to SARS-CoV-2 infection in patients after the resolution of COVID-19 using complete ocular examinations and optical coherence tomography (OCT). In this cross-sectional study, conducted from May 30 to October 30, 2020, patients who recovered from various stages COVID-19 underwent eye examination and multimodal retinal imaging (Retinographies and Spectral-OCT). We included 50 patients, 29 (58%) males, median age of 46.5 [standard deviation 15.8]. Of these, 42% (21) had mild, 18% (9) had severe and 40% (20) had critical disease. The median time interquartile range (IQR) between symptom onset and ocular examination was 55 days [IQR 39-71]. Seven patients (14%) reported ophthalmic symptoms, transitory low visual acuity (6%) and retroocular pain (8%). On OCT, one patient without comorbidities had sectoral retinal pallor suggestive of acute retinal ischaemia and oedema of the retina's inner layers and atrophy. All findings progressively and spontaneously improved months after resolution of COVID-19. Patients with COVID-19 present findings compatible with the general population depending on age and comorbidities; nevertheless, acute retinal findings associated with the disease may be present, such as caused either by the direct effects of retinal SARS-CoV-2 infection, by indirect effects of the cytokine storm or by the pro-thrombotic state associated with COVID-19. Therefore, retinal involvement in patients with COVID-19 remains subject to considerable discussion and study.