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The analysis of variability in Atmospheric Angular Momentum (AAM) and Length of day (LOD) of Abarca del Rio et al. [Ann. Geophys. 18 (2000) 347] is extended to investigate a possible connection with solar activity fluctuations from interannual to secular time scales. The southern oscillation index and records of sea surface temperature are used as proxy series in this analysis during the era prior to the availability of AAM analyses. At interannual times scales, the variability in AAM and LOD agrees with that in solar activity with regard to the decadal cycle in the stratospheric quasi biennial oscillation and solar activity but whose phases are slowly shifting from one another with time, while the stratospheric quasi biennial cycle agrees with the solar quasi biennial cycle, though led by 6 years. At decadal times scales, AAM varies statistically with the solar decadal cycle over much of the last century since 1930–1940. The decadal mode in AAM is suggested here to be generated by upward propagation of surface atmospheric modes, from the surface throughout the troposphere through the stratosphere. Equatorial Sea Surface Temperature (SST) variability may be considered a proxy index for AAM variability because of the relationship to the El Nino/Southern Oscillation; its analysis over the last three centuries (1730–2000) and that of LOD since 1830 confirm the agreement found over the last part of the 20th century, as well as the general disagreement before. [Copyright &y& Elsevier]

Slow movement processes correspond to slow to extremely slow deformation in slopes. Slow movement is often known to be the cause of severe damage to structures and infrastructures. In the Northern Biobío hillside (NBH), many slow movements were not previously identified, which led to building damage. To evaluate their triggering factors, we use two complementary techniques: interferometry of synthetic aperture radar (InSAR) and electrical resistivity tomography (ERT). We observed deformation patterns using SAR data derived from PALSAR-1 during a year that exhibited extreme rainfall (2006). We established that reactivation of slow movements occurs during extreme rainfall periods, which can be observed through deformation patterns. ERT inversion results reveal a formation of silt and clay layers. Our results indicate the existence of slow movement processes close to densely populated areas. An interpretation of InSAR and ERT results showed that during extreme rain events, soil saturation occurs. The silt layer loads the hillslope and the clay layer acts as a lubricant below the silt. [ABSTRACT FROM AUTHOR]

We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20–23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays. [ABSTRACT FROM AUTHOR]

Abstract: An accurate and continuous monitoring of lakes and inland seas is available since 1993 thanks to the satellite altimetry missions (Topex–Poseidon, GFO, ERS-2, Jason-1, Jason-2 and Envisat). Global data processing of these satellites provides temporal and spatial time series of lakes surface height with a decimetre precision on the whole Earth. The response of water level to regional hydrology is particularly marked for lakes and inland seas in semi-arid regions. A lake data centre is under development at by LEGOS (Laboratoire d’Etude en Géophysique et Océanographie Spatiale) in Toulouse, in coordination with the HYDROLARE project (Headed by SHI: State Hydrological Institute of the Russian Academy of Science). It already provides level variations for about 150 lakes and reservoirs, freely available on the web site (HYDROWEB: http://www.LEGOS.obs-mip.fr/soa/hydrologie/HYDROWEB), and surface-volume variations of about 50 big lakes are also calculated through a combination of various satellite images (Modis, Asar, Landsat, Cbers) and radar altimetry. The final objective is to achieve in 2011 a fully operating data centre based on remote sensing technique and controlled by the in situ infrastructure for the Global Terrestrial Network for Lakes (GTN-L) under the supervision of WMO (World Meteorological Organization) and GCOS (Global Climate Observing System). [Copyright &y& Elsevier]

Abstract: Results of various authors on long-term trends in foF2, which is equivalent to the maximum electron density in the ionosphere, and their interpretation do not reveal a consistent pattern. Therefore, a joint analysis of one carefully selected dataset was performed by six teams, which used different approaches to trend determination. High-quality data of station Juliusruh (54.6°N, 13.4°E) for noon (average from 10 to 14UT) were used for the period of two solar cycles from minimum to minimum (1976–1996). Juliusruh is relatively sensitive to geomagnetic activity as an almost subauroral station, which might play some role in interpretation of trend results. Various methods provide results, which differ to some extent, even when one co-author applies different methods. Another source of differences is application of various ways of removal (or at least large suppression) of the effect of solar (and geomagnetic) activity. Nevertheless finally most teams obtained quite comparable results. Interpretation of the observed trends is not unique—co-authors consider either the long-term change in geomagnetic activity, or anthropogenic effects to be predominantly responsible for trends. There is some generally accepted output from the joint analysis. All trends are either negative or insignificant. Data corrections with sunspot number (R), F10.7 adjusted to the Sun–Earth distance, observed F10.7, adjusted E10.7 and observed E10.7 result in somewhat different trends; the observed F10.7 and E10.7 appear to be the best correcting factor. The trends in foF2 are very small, of the order of −0.01MHz/year, much smaller than the solar cycle effect and, therefore, sensitive to the solar activity correction. The Juliusruh dip angle increased very little over the period 1976–1996 and the possible impact of that increase on trends is negligibly small. [Copyright &y& Elsevier]