Geometric analysis of variability of radiocarbon abundances and solar activity

The SBUV/SBUV2 (65° S–65° N) and Bodeker Scientific (90° S–90° N) satellite databases have been used for composite and cross-wavelet analyses of the spatio-temporal variability of phase relations between a 11-year cycle of solar activity (SA) and quasi-decennial oscillations (QDOs) of total ozone content (TOC). For globally average TOC values, the QDO maxima coincide in phase with the solar-activity maxima, and amplitude variations of TOC correlate with those of the 11-year solar cycle. According to the analysis of amplitude and phase of QDOs for the zonal average TOC fields, a QDO amplitude is about 6–7 Dobson Units (DU) in the high northern and southern latitudes, and it does not exceed 2–3 DU in the tropic regions. The latitudinal TOC variations are distinguished by a delay of the quasi-decennial oscillation phase in the southern latitudes in comparison with the northern latitudes. The TOC maxima phase coincides with the SA maxima phase in the tropic regions; the TOC variations go ahead of the SA variations, on average, in moderate and high latitudes of the Northern Hemisphere; the TOC variations are behind the SA variations in the Southern Hemisphere. The phase delay between TOC QDO maxima in the northern and southern latitudes appears to increase in the course of time, and the TOC quasi-decennial variations in the Arctic and Antarctic subpolar regions occur approximately in an antiphase over the last two decades.

Solar activity and earth rotation variability

Analysis of water resources variability of the Caspian and Aral sea basins on the basis of solar activity

Analysis of water resources variability of the Caspian and Aral sea basins on the basis of solar activity

INSPIRE-SAT 7 is a French 2U CubeSat very similar to the satellite UVSQ-SAT which was launched on 24 January 2021. The main purpose of INSPIRE-SAT 7 is the measurement of the Earth’s radiation budget at the top of the atmosphere. Its total mass is ~3.0 kg and its averaged power consumption 3 W. It will orbit at a maximum altitude of 600 km on a Sun-synchronous orbit with a descending node at ~0930 LT. The IONO experiment embarked on INSPIRE-SAT 7 is dedicated to the sounding of the Earth’s ionosphere which results from the ionization of the upper atmosphere due to UV radiations and X-rays coming from the Sun. The electron density in the ionosphere depends on the local time, the season, and the solar activity. The propagation of the radio waves is affected by the electron density and also by refraction and reflection phenomena. We consider the following goals for the IONO instrument: improving ionosphere models, in particular the IRI (International Reference Ionosphere); study of the propagation of electromagnetic waves in the ionosphere and the factors which can disturb it (e.g., thunderstorms); analysis of temporal and spatial variability at different scales; study of the coupling between ionosphere and magnetosphere, and the electrical circuit between ionosphere and lithosphere. The observations collected by IONO will be compared to those produced by a VLF-LF antenna network designed for investigating the perturbations of the ionosphere, and the wave propagation, by seismic phenomena.

Study regionAfrica Study focusAfrican rainfall shows significant year-to-year natural fluctuations that in part are linked to teleconnections associated with modes of variability in the Atlantic, Pacific and Indian oceans. A better understanding of African rainfall variability and potential drivers would help to better prepare African societies for anticipated droughts and floods by taking early precautionary action. Here we are presenting the first continent-wide analysis of African rainfall variability on a month-by-month and country-by-country basis. We have calculated Pearson r values for smoothed monthly rainfall data of 49 African countries over the period 1901–2017 which we compared to six potential climatic drivers of natural variability, namely AMO, NAO, ENSO (El Niño Southern Oscillation), Pacific Decadal Oscillation (PDO), Indian Ocean Dipole (IOD) and solar activity changes. We allowed time lags of up to 11 months for each potential driver (66 months for solar activity). New hydrological insights for the regionThe dynamic temporal-spatial evolution of the seasonal Pearson correlations was mapped out across the continent, tracking the gradual or abrupt expansion, displacement and subsequent waning of the various effects over the course of the year. Relationships are complicated by characteristic time lags, non-stationary correlations and occasional phase shifts. Our empirical results may help to further improve short- to midterm rainfall prognoses in Africa and provide important calibration data for the further improvement of climate models.

Spatio-temporal analysis of ionospheric disturbances for ground based augmentation systems over a midlatitude region

Adequate water resources management includes understanding patterns and spatiotemporal variability of precipitation, as this variable is determinant for ecosystems’ stability, food security, and most human activities. Based on satellite estimations validated through ground measurements from 59 meteorological stations, the objective of this study is to evaluate the long-term spatiotemporal variability and trends of the average monthly precipitation in the Magdalena Department, Colombia, for the 1981–2018 period. This heterogeneous region comprises many different ecoregions in its 23,188 km2 area. The analysis of spatial variability allowed for the determination of four different subregions based on the differences in the average values of precipitation and the degree of rainfall variability. The trend analysis indicates that the current rainfall patterns contradict previous estimates of a progressive decrease in annual averages due to climate change in the study region, as most of the department does not exhibit statistically significant trends, except for the Sierra Nevada de Santa Marta area, where this study found reductions between 10 mm yr−1 and 30 mm yr−1. The findings of this study also suggest the existence of some links between precipitation patterns with regional phenomena of climate variability and solar activity.

Sun-Earth coupling studies can explain some physical mechanisms of how solar activity exerts their influences on weather/climate changes. Using the GPS-derived precipitable water vapour (PWV) measurements as a tool to study water vapour variability, it is fundamental to calculation of a reliable weather forecast for advancement space weather prediction and such methods provide suitable platforms for the studies of solar-climate relationship. This paper presents an analysis of the PWV variability and its responses to solar activity during the declining phase of solar cycle 23.

Coral-based reconstructions of sea surface temperatures (SSTs) using Sr/Ca, U/Ca and δ 18 O are important tools for quantitative analysis of past climate variabilities. However, post-depositional alteration of coral aragonite, particularly early diagenesis, restrict the accuracy of calibrated proxies even on young corals. Considering the diagenetic effects, we present new Mid to Late Holocene SST reconstructions on well-dated (U/Th: ∼70 yr to 5.4 ka) fossil Porites sp. collected from the Society Islands, French Polynesia. For few corals, quality pre-screening routines revealed the presence of secondary aragonite needles inside primary pore space, resulting in a mean increase in Sr/Ca ratios between 5-30%, in contrast to the massive skeletal parts. Characterized by a Sr/Ca above 10 mmol/mol, we interpret this value as the threshold between diagenetically altered and unaltered coral material. At a high-resolution, observed intra-skeletal variability of 5.4 to 9.9 mmol/mol probably reflects the physiological control of corals over their trace metal uptake, and individual variations controlled by CaCO 3 − precipitation rates. Overall, the Sr/Ca, U/Ca and δ 18 O trends are well correlated, but we observed a significant offset up to ± 7 • C among the proxies on derived palaeo-SST estimates. It appears that the related alteration process tends to amplify temperature extremes, resulting in increased SST-U/Ca and SST-Sr/Ca gradients, and consequently their apparent temperature sensitivities. A relative SST reconstruction is still feasible by normalizing our records to their individual mean value defined as SST. This approach shows that SST records derived from different proxies agree with an amplitudinal variability of up to ± 2 • C with respect to their Holocene mean value. Higher SST values than the mean SSTs (Holocene warm periods) were recorded from ∼1.8 to ∼2.8 ka (Interval I), ∼3.7 to 4.0 ka (Interval III) and before ∼5 ka, while lower SST values (Holocene cold periods, Interval II and IV) were recorded in between. The ensuing SST periodicity of ∼1.5 ka in the Society Islands record is in line with the solar activity reconstructed from 10 Be and 14 C production (Vonmoos et al., 2006), emphasizing the role of solar activity on climate variability during the Late Holocene.

Modeling and analysis of ionospheric TEC variability from GPS–TEC measurements using SSA model during 24th solar cycle

Generalized thermostatistics and wavelet analysis of solar wind and proton density variability

Coral-based reconstructions of sea surface temperatures (SSTs) using Sr/Ca, U/Ca and d18O are important tools for quantitative analysis of past climate variabilities. However, post-depositional alteration of coral aragonite, particularly early diagenesis, restrict the accuracy of calibrated proxies even on young corals. Considering the diagenetic effects, we present new Mid to Late Holocene SST reconstructions on well-dated (U/Th: ca. 70 yr to 5.4 ka) fossil Porites sp. collected from the Society Islands, French Polynesia. For few corals, quality pre-screening routines revealed the presence of secondary aragonite needles inside primary pore space, resulting in a mean increase in Sr/Ca ratios between 5-30%, in contrast to the massive skeletal parts. Characterized by a Sr/Ca above 10 mmol/mol, we interpret this value as the threshold between diagenetically altered and unaltered coral material. At a high-resolution, observed intra-skeletal variability of 5.4 to 9.9 mmol/mol probably reflects the physiological control of corals over their trace metal uptake, and individual variations controlled by CaCO3- precipitation rates. Overall, the Sr/Ca, U/Ca and d18O trends are well correlated, but we observed a significant offset up to +/- 7°C among the proxies on derived palaeo-SST estimates. It appears that the related alteration process tends to amplify temperature extremes, resulting in increased SST-U/Ca and SST-Sr/Ca gradients, and consequently their apparent temperature sensitivities. A relative SST reconstruction is still feasible by normalizing our records to their individual mean value defined as 1SST. This approach shows that 1SST records derived from different proxies agree with an amplitudinal variability of up to +/- 2°C with respect to their Holocene mean value. Higher 1SST values than the mean SSTs (Holocene warm periods) were recorded from ca. 1.8 to ca. 2.8 ka (Interval I), ca. 3.7 to 4.0 ka (Interval III) and before ca. 5 ka, while lower 1SST values (Holocene cold periods, Interval II and IV) were recorded in between. The ensuing SST periodicity of ca. 1.5 ka in the Society Islands record is in line with the solar activity reconstructed from 10Be and 14C production (Vonmoos et al., 2006), emphasizing the role of solar activity on climate variability during the Late Holocene.

<p>INSPIRE-SAT 7 is a French 2 Unit CubeSat weighting approximately 3 kg, very similar to the satellite UVSQ-SAT which was launched on 24 January 2021. Its main purpose is the measurement of the Earth’s radiation budget at the top of the atmosphere and the sounding of the ionosphere. It will orbit at a maximum altitude of 600 km on a Sun-synchronous orbit with a descending node at ~0930 LT. The IONO experiment embarked on the CubeSat is dedicated to the sounding of the Earth’s ionosphere. The latter results from the ionization of the upper atmosphere due to UV radiations and X-rays coming from the Sun. The electron density in the ionosphere depends on the local time, the season, and the solar activity. The propagation of the radio waves is affected by the electron density and also by refraction and reflection phenomena. We consider the following goals for the IONO instrument: improving ionosphere models, in particular the IRI (International Reference Ionosphere); study of the propagation of electromagnetic waves in the ionosphere and the factors which can disturb it (e.g., thunderstorms); analysis of temporal and spatial variability at different scales; study of the coupling between ionosphere and magnetosphere, and the electrical circuit between ionosphere and lithosphere. The observations collected by IONO will be compared to those produced by a VLF-LF antenna network designed for investigating the perturbations of the ionosphere, and the wave propagation, by seismic phenomena.</p>

We present the results of studying year-to-year changes in the variabilities of the mesopause temperature and the peak electron density from the observational data of the complex of instruments of the Institute of Solar-Terrestrial Physics SB RAS in 2008-2020. The analysis involved data on solar and geomagnetic activity, as well as on variations in the Southern Oscillation Index (SOI). We revealed a correlation between the day-to-day variability of the mesopause temperature and SOI variations, with a peak in the La Niña phase and a minimum in the El Niño phase. An analysis of the ionospheric variability and their comparison with changes in geomagnetic and solar activity revealed, that only day-to-day ionospheric variability correlates unambiguously with geomagnetic activity.