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On 8 April 2024, a rare total solar eclipse (TSE) passed over western New York State (NYS), the first since 1925 and the last one until 2079. The NYS Mesonet (NYSM) consisting of 126 weather stations with 55 on the totality path provides unprecedented surface, profile, and flux data and camera images during the TSE. Here we use NYSM observations to characterize the TSE's impacts at the surface, in the planetary boundary layer (PBL), and on surface fluxes and CO2 concentrations. The TSE‐induced peak surface cooling occurs 17 min after the totality and is 2.8°C on average with a maximum of 6.8°C. It results in night‐like surface inversion, calm winds, and reduced vertical motion and mixing, leading to the shallowing of the PBL and its moistening. Surface sensible, latent and ground heat fluxes all decrease whereas near‐surface CO2 concentration rises as photosynthesis slows down. Plain Language Summary: On 8 April 2024, a rare total solar eclipse (TSE) passed over western New York State (NYS), the first one since 1925 and the last one until 2079. The entire NYS witnessed at least 88% obscuration at the peak of the eclipse. It provides an excellent opportunity to study the impacts of the TSE. The NYS Mesonet (NYSM), an advanced statewide weather network, has 55 stations on the totality path and provides unprecedented measurements of surface meteorological variables, atmospheric vertical profiles, the heat exchange between the atmosphere and the surface and carbon dioxide (CO2) concentration. It enables one to study the TSE in greater details on a regional scale for the first time. This study found that the moon shadow cools the surface by as much as 6.8°C and creates a surface inversion layer. The cooling calms down winds and vertical mixing, leading to less escape of the water vapor and moistening of the air. It also reduces the heat exchange between the surface and the air. Without sunlight, the photosynthesis shuts down, causing a robust rise in near‐surface CO2 concentration. One‐minute camera images provide a fantastic view of the darkening of the sky during the TSE. Key Points: The New York State Mesonet provided unprecedented surface, profile, flux and image data during the 8 April 2024 total solar eclipse across New York StateThe eclipse resulted in significant cooling and moistening near the surface and in the boundary layer, leading to a surface inversion layerIt also weakened surface winds, turbulent mixing, heat fluxes, but caused a robust rise in near‐surface CO2 concentrations [ABSTRACT FROM AUTHOR]

A total solar eclipse provides an unparalleled opportunity to study the changes in the atmosphere's planetary boundary layer (PBL) due to changes in radiative heating. Although previous eclipse studies have demonstrated that significant changes occur, few studies have explored the evolution of these changes. To better understand the changes in the lowest layers of the PBL during an eclipse, a multi-sensor sampling approach was taken. Radiosonde launches were used to explore the depth of the column, while Unmanned Aerial Vehicles (UAVs) were used to document with high-resolution the brief changes in the vertical structure of the PBL caused by the eclipse. These changes highlighted differences from previous studies that relied solely on radiosonde and/or mesonet data alone. Higher-resolution sampling of the lower PBL showed a delay in the local vertical mixing as well as changes in the PBL height from pre- to post-eclipse. Slow responses were noted at the top of the PBL while very rapid changes to the PBL profile were captured in the near-surface layer. These changes highlighted differences from previous studies that relied solely on radiosonde and/or mesonet data alone. A preliminary analysis of the collected data highlighted a slow response to the eclipse near the top of the planetary boundary layer (radiosonde data) with very rapid changes noted in the near surface layer (UAV data). Preliminary results show that PBL heights remained nearly constant until well after third contact when a 35 hPa lowering of the PBL heights was observed and were limited to the lowest 25 hPa. The UAV soundings demonstrated the development of a strong inversion where the air below 990 hPa rapidly cooled with a nearly 1 °C drop in temperature observed. These observed changes raise interesting questions about how the lower and upper parts of the planetary boundary layer interact. [ABSTRACT FROM AUTHOR]

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A total solar eclipse was recorded in a classic Chinese book with the title The Travels of an Alchemist: the Journey of the Taoist Ch'ang Ch'un from China to the Hindukush at the Sumons of Chingiz Khan. In the present paper, possible locations of the solar eclipse observation are investigated, taking into account the geographical characteristics of local environments. With a modern astronomical planetary ephemeris, the authors confirm the observation records and derive an upper limit of +768 seconds for the Δ T value at the epoch A.D. 1221. [ABSTRACT FROM AUTHOR]

The total solar eclipse of 21 August 2017 was unique in that the path of totality swept across the high spatial and temporal resolution QuantumWeather® mesonet and was very near the city of St. Louis Missouri. Thus, the meteorological response to the eclipse was complicated by the St. Louis urban heat island. Temperature changes of up 4 °C were observed across the network. Composite meteograms for rural, suburban, and urban stations displayed significant differences in the observed temperature and pressure response to the eclipse with a peak amplitude at the time of the eclipse. The differing response suggests that the urban heat island and changes in land surface characteristics alter the temperature and pressure response by the passage of the eclipse shadow. Oscillations in the composite meteograms appear to be the consequence of the passage of an outflow boundary across the network. As the outflow boundary moves north to south, the outflow boundary manifests its presence in the pressure field as a damped oscillation. Sounding data were collected along the center line of eclipse and along the southern edge of the eclipse before and during the eclipse. The soundings show that the eclipse altered the boundary layer height, the lowest layer of the atmosphere, in an unexpected way. [ABSTRACT FROM AUTHOR]

The results obtained during the total Solar Eclipse on July 2, 2019, in Chile are presented together with the Eclipse K-corona Polarimeter (EKPol). The EKPol is equipped with an electro-optically modulating Liquid-Crystal Variable Retarder (LCVR) for the polarimetric observation of the solar corona. The use of this technology has been an important ground-based test for the application of this technology in space-based observatories. The usage of LCVRs in a polarization rotator configuration allows the replacement of mechanically rotating retarders avoiding moving parts and reducing noise, failure probability, and mass. Indeed, EKPol was developed as a technology demonstrator for the Metis coronagraph on-board Solar Orbiter. The results, from the composition of the image to the electron density map evaluation, are compared and are consistent with what is obtained by other ground- and space-based instruments, and with past EKPol campaigns. [ABSTRACT FROM AUTHOR]

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (

The 2019 Solar Eclipse, whose umbra occurred in the Coquimbo region (Chile), provided the opportunity to diagnose the development of astrotourism in the territory and reflect on the strategies necessary for its improvement. This research analyzes the quality of the tourist's astrotourism experience, through a binary logistic regression model. The results reveal that, in general, travelers were satisfied, however it is noted that foreign tourists have less intention of repeating the visit and recommending the destination (loyalty). The findings are expected to help improve the competitiveness of Chile's astrotourism. [ABSTRACT FROM AUTHOR]

Solar eclipses provide an excellent opportunity to study the effects of a sudden localized change in photoionization flux in the Earth's ionosphere and its consequent repercussion in the Geomagnetic field. We have focused on a subset of the data available from the North American 2017 eclipse in order to study VTEC measurements from GNSS data and geomagnetic field estimations from INTERMAGNET observatories near the eclipse path. Our simultaneous analysis of both datasets allowed us to quantify the ionosphere and magnetic field reaction to the eclipse event with which allowed us to compare how differently these take place in time. We found that studying the behaviour of VTEC differences with respect to reference values provides better insight of the actual eclipse effect and were able to characterize the dependence of parameters such as time delay of maximum depletion and recovery phase. We were also able to test models that link the ionospheric variations in a quantitative manner. Total electron content depletion measured from GNSS were fed into an approximation of Ashour-Chapman model at the locations of geomagnetic observatories and its predictions match the behaviour of magnetic field components in time and magnitude strikingly accurately. [ABSTRACT FROM AUTHOR]

A total solar eclipse occurred at the ascending node of the Moon's orbit on 2 July 2019, with an eclipse magnitude of 1.0459. The totality was visible from the southern Pacific Ocean east of New Zealand to the Coquimbo Region (Chile) and Central Argentina at sunset, with the maximum of 4 min 32 s visible from the Pacific Ocean. The recent Great American Eclipse, 21 August 2017, clearly showed that the ionosphere is strongly affected by the totality. In order to explore the ionospheric signature of the 2019 eclipse, we use data of ∼110 GNSS stations seeing multiple GPS and GLONASS satellites to visualize the eclipse signature on the total electron content (TEC) in the southern hemisphere. The location of the South American GNSS stations, at the end of the path of totality, right before sunset, makes the eclipse signature in the ionospheric TEC act like an early sunset with 15 TEC‐Unit variations, corresponding to 40% of background ionization. The effect reaches only four TEC‐Units, corresponding to 25%–40% of background ionization, for the more westerly observations, where we clearly highlight the effect of the eclipse in the ionosphere and the following recovery to normality. By applying the omega‐k analysis, we can find TIDs with wavelengths of around 100 km and larger than 200 km and with periods of 20–50 min, which supports the results of the Great American Eclipse. Using different grids, we can also prove the robustness of the omega‐k analysis. Plain Language Summary: A total solar eclipse occurred on 2 July 2019 over the Pacific Ocean and South America with the eclipse shadow reaching the eastern coast of South America near Buenos Aires around sunset. We calculate the differential total electron content (TEC) to visualize the evolution of the phenomena with high spatial and temporal resolution. The effect of the eclipse in the ionosphere is clearly visible and appears as TEC depletion, which for some stations of central and eastern South America looks just like an early sunset. The omega‐k analysis confirms the results of the Great American Eclipse regarding wavelength and period of the TIDs induced by the shadow of the Moon. Using different grids, we proved the robustness of the omega‐k analysis. The effect of the solar eclipses in the southern hemisphere is coherent with the observations in the northern hemisphere even if we do not recognize the presence of bow waves. Key Points: GNSS observations of solar eclipse show total electron content (TEC) depletionsWe observe TIDs of >200‐km wavelength that are related to the TEC depletion due to the Moon's shadowTotal solar eclipse proves robustness of the omega‐k analysis [ABSTRACT FROM AUTHOR]

Studies concerning solar eclipses have been rising significantly, yet, different circumstances during their occurrence provide uniqueness to every study. This paper studies the ionospheric and meteorological response to the total solar eclipses of August 21, 2017, March 20, 2015 and August 1, 2008. The ionospheric total electron content (TEC) was calculated from the signals beamed by the dual-frequency Global Positioning System (GPS) satellites and accessed from University NAVSTAR Consortium (UNAVCO) data archive. Similarly, the data of meteorological parameters were accessed from the historical climate archive of respective countries. The TEC drop of ∼2–7 TECU with a lag of ∼15–30 min is observed at varying latitudes which correspond with the findings of numerous past research. We analyzed the data of 15 stations under ∼100% obscuration to rule out the varying effects of different obscuration rates. Yet, given the turbulent nature of climate, we found varying changes at observed locations. A good relationship, however, was observed in 8 of the stations, where temperature drop ranged from 0.4 °C to 6.11 °C, and rise in relative humidity ranged from 0 to ∼77%. Wind speed has shown the most turbulent behavior. Their change was largely impacted by the eclipse on 5 of the stations, while the local factor was dominant on the others. In spite of this, the stations under observation showed distinct responses to the ionospheric change during the total solar eclipses, thus demonstrating the relation of meteorological parameters with eclipses. [ABSTRACT FROM AUTHOR]

A change in the phase of the received signal during a total solar eclipse on 31 July 1981 is considered. Theexperimental data were obtained from the phase of the signals received by the Omega radio navigation system. The distribution path captures both the auroral oval and the mid-latitude zone. It is shown that it is very difficult to distinguish the phase deviation of thereceived signal during a solar eclipse. Other parameters that affect the propagation of signals in the auroral zone must be taken into account.

We report observations of the total solar eclipse of 14 December 2020, during which a coronal mass ejection was seen to propagate. A comprehensive set of photographs covering a high dynamic range of exposure enabled characterization of its dimensions. Displacement of the front can be seen during the few minutes of totality.

The Southern Andes, in Patagonia, are a well‐known hotspot of orographic gravity waves (oGWs) during winter when atmospheric conditions, such as temperature, wind speed, and wind direction, favor their generation and propagation. In the summer, oGWs above the mesosphere and oGW‐induced ionospheric perturbations are rarely observed because vertical wave propagation conditions are unfavorable. Nevertheless, when atmospheric conditions deviate significantly from those typical of summer, for example, during a solar eclipse (SE), the atmospheric temperature and wind changes can allow oGWs to reach ionospheric heights. Global Navigation Satellite Systems (GNSS)‐based ionospheric total electron content (TEC) studies of the 2017 North American eclipse showed oGW‐compatible observations near the totality zone around the Rocky Mountains, and it was suggested, but not shown, that these were likely oGWs. In this work, we report, model, and interpret GNSS TEC perturbations observed during the December 14, 2020 total SE in South America. TEC data recorded near the Andes during this total SE are in good agreement with predictions by the SAMI3 ionospheric model until shortly after the passage of the umbra. TEC data after totality can best be explained with the interpretation that the observation of oGWs was favored by the passage of the eclipse over the Andes Mountains. Key Points: A physics‐based model can be used together with detrending techniques to identify wave‐induced total electron content perturbationsAtmospheric gravity waves were detected using virtual array beamforming over the Andes during the 2020 total solar eclipse in South AmericaThe eclipse appears to have favored the vertical propagation of orographic gravity waves into the thermosphere [ABSTRACT FROM AUTHOR]

A total solar eclipse affected southern South America on December 14, 2020. Its occurrence close to the summer solstice in the Southern Hemisphere and around noon brought almost ideal conditions to study the effects of the sudden reduction in incoming solar radiation on different atmospheric variables. Interestingly, the astronomical phenomenon moved over a region that at that time was being affected by a cold front accompanied by significant cloudiness and cold air advection to the area. Therefore, the actual drop in surface temperature over the umbra region resulted from a combination of the radiative effect (i.e., the reduction in solar radiation due to the eclipse itself) and a circulation effect related to the injection of colder air. A quantification of both effects on the full temperature variation is provided, along with a discussion on the underlying mechanisms and the related effects on surface winds derived from the cooling. Results show that temperature drops associated with total solar eclipses in areas far away from the umbra can be as high as (or even higher than) those within the umbra, depending on the prevailing weather conditions. [ABSTRACT FROM AUTHOR]

On 20 March 2015, a total solar eclipse occurred over Ny-Ålesund (78.9° N, 11.9° E), Svalbard, under ideal conditions with clear sky. The cycle of the radiation fluxes is comparable with other experiments during eclipses, with even the upward longwave radiation showing significant changes, with a delay to the shortwave radiation and a slowly linear increase after the totality. Also, under polar conditions, an increase of the wind velocity before and a decrease after the totality was found, which is an indicator of the generation of an “Eclipse cyclone”. This change of the wind direction generated a local wind system with a near-surface-layer katabatic flow. During the eclipse, a remarkably large sensible heat flux was observed. The turbulent fluxes were analysed using a wavelet technique with 1-minute time resolution, which is the ideal method for investigating these highly non-steady conditions. No influences on the boundary layer structure as measured with radiosondes were found, with the exception of a wind direction change during the eclipse cyclone below the shallow inversion layer.

Rapid changes in solar radiative forcing influence heat, scalar and momentum fluxes and thereby shift the trajectory of near-surface atmospheric transitions. Surface fluxes are difficult to obtain during atmospheric transitions by either bulk or eddy-covariance methods because both techniques assume quasi-stationarity in an atmospheric state and require sufficiently long blocks of data, typically on the order of 10–30 min, to obtain statistically significant results. These computational requirements limit the temporal resolution of atmospheric processes that researchers can examine using traditional measurement techniques. In this paper, we present a novel observational approach to calculate surface fluxes at sub-minute temporal resolutions. High-frequency data from a horizontal, log-spaced array of nine time-synchronized ultrasonic anemometers were used to perform spatial-temporal ensemble averaging and to obtain eddy-covariance turbulence fluxes at unprecedented time resolutions. The 2017 Great American Solar Eclipse event provided a “natural experiment” to test the ensemble-observation and averaging approach. A total eclipse is energetically well-constrained and, unlike day/night transitions, is a perturbation that quickly transitions from and back to a state of significant solar forcing, providing an ideal scenario for testing the space-timescales required for surface flux calculations. Additionally, two Doppler lidars and a vertically-oriented Distributed Temperature Sensing (DTS) system provided measurements to characterize near-surface atmospheric conditions. Results show that the ensemble-averaged sensible heat fluxes converged at timescales as short as 15 s. Additional analyses show that the timescale of the connection between the surface and the atmosphere is more rapid than previous measurements have been capable of showing and is on the order of 10 min or less. This experiment demonstrates that ensemble-flux measurements are capable of resolving fluctuations in surface fluxes during rapid atmospheric transitions.