A decadal variation of tropical lower stratospheric ozone and temperature has previously been identified that correlates positively with the 11 year solar activity cycle. However, the El Niño–Southern Oscillation (ENSO) also influences lower stratospheric ozone and temperature. It is therefore legitimate to ask whether quasi-decadal ENSO variability can contribute to this apparent solar cycle variation, either accidentally because of the short measurement record or physically because solar variability affects ENSO. Here we present multiple regression analyses of available data records to compare differences in results obtained with and without including an ENSO term in the statistical model. In addition, simulations are performed using the NRL NOGAPS-ALPHA GCM for warm/cold ENSO conditions to test for consistency with the ENSO regression results. We find only very minor changes in annual mean solar regression coefficients when an ENSO term is included. However, the observed tropical ENSO response provides useful insights into the origin of the unexpected vertical structure of the tropical solar cycle ozone response. In particular, the ENSO ozone response is negative in the lower stratosphere due to increased upwelling but changes sign, becoming positive in the middle stratosphere (5–10 hPa) due mainly to advective decreases of temperature and NOx, which photochemically increase ozone. A similar mechanism may explain the observed lower stratospheric solar cycle ozone and temperature response and the absence of a significant response in the tropical middle stratosphere.

Previous multiple regression analyses of the solar cycle variation of stratospheric ozone are improved by (1) analyzing three independent satellite ozone data sets with lengths extending up to 25 years and (2) comparing column ozone measurements with ozone profile data during the 1992–2003 period when no major volcanic eruptions occurred. Results show that the vertical structure of the tropical ozone solar cycle response has been consistently characterized by statistically significant positive responses in the upper and lower stratosphere and by statistically insignificant responses in the middle stratosphere (∼28–38 km altitude). This vertical structure differs from that predicted by most models. The similar vertical structure in the tropics obtained for separate time intervals (with minimum response invariably near 10 hPa) is difficult to explain by random interference from the QBO and volcanic eruptions in the statistical analysis. The observed increase in tropical total column ozone approaching the cycle 23 maximum during the late 1990s occurred primarily in the lower stratosphere below the 30 hPa level. A mainly dynamical origin for the solar cycle total ozone variation at low latitudes is therefore likely. The amplitude of the solar cycle ozone variation in the tropical upper stratosphere derived here is somewhat reduced in comparison to earlier results. Additional data are needed to determine whether this upper stratospheric response is or is not larger than model estimates.

A linear multiple regression statistical model is applied to estimate the solar induced component of odd nitrogen variability in the stratosphere and lower mesosphere using UARS HALOE data for 1991–2003. Consistent with earlier studies, evidence is obtained for a decadal NOx variation at the highest available latitudes (50° – 70°) that projects positively onto the solar cycle. This variation, which is most statistically significant in the Southern Hemisphere, also correlates positively with the auroral Ap index. It is therefore probably caused by downward transport during the polar night of thermospheric and mesospheric odd nitrogen. In addition, at low latitudes near and above the stratopause, evidence is obtained for an inverse solar cycle NOx variation. It is suggested that this low-latitude response may be caused primarily by increased photolysis of NO under solar maximum conditions. Throughout most of the rest of the stratosphere, no statistically significant response is obtained.

The 11 year solar-cycle component of climate variability is assessed in historical simulations of models taken from the Coupled Model Intercomparison Project, phase 5 (CMIP-5). Multiple linear regression is applied to estimate the zonal temperature, wind and annular mode responses to a typical solar cycle, with a focus on both the stratosphere and the stratospheric influence on the surface over the period ∼1850–2005. The analysis is performed on all CMIP-5 models but focuses on the 13 CMIP-5 models that resolve the stratosphere (high-top models) and compares the simulated solar cycle signature with reanalysis data. The 11 year solar cycle component of climate variability is found to be weaker in terms of magnitude and latitudinal gradient around the stratopause in the models than in the reanalysis. The peak in temperature in the lower equatorial stratosphere (∼70 hPa) reported in some studies is found in the models to depend on the length of the analysis period, with the last 30 years yielding the strongest response. A modification of the Polar Jet Oscillation (PJO) in response to the 11 year solar cycle is not robust across all models, but is more apparent in models with high spectral resolution in the short-wave region. The PJO evolution is slower in these models, leading to a stronger response during February, whereas observations indicate it to be weaker. In early winter, the magnitude of the modelled response is more consistent with observations when only data from 1979–2005 are considered. The observed North Pacific high-pressure surface response during the solar maximum is only simulated in some models, for which there are no distinguishing model characteristics. The lagged North Atlantic surface response is reproduced in both high- and low-top models, but is more prevalent in the former. In both cases, the magnitude of the response is generally lower than in observations.

The Madden-Julian oscillation (MJO), also known as the 30-60day oscillation, is the strongest of the intraseasonal climate oscillations in the tropics and has significant derivative effects on extratropical circulation and intraseasonal climate. It has recently been shown that the stratospheric quasi-biennial oscillation (QBO) modulates the amplitude of the boreal winter MJO such that MJO amplitudes are larger on average during the easterly phase (QBOE) than during the westerly phase (QBOW). A major possible mechanism is the decrease in static stability in the lowermost stratosphere under QBOE conditions resulting from relative upwelling associated with the QBO-induced meridional circulation. Here evidence is presented that tropical upwelling changes related to the 11year solar cycle also modulate the boreal winter MJO. Based on 37.3years of MJO amplitude data, the largest amplitudes and occurrence rates, and the weakest static stabilities in the tropical lower stratosphere, occur during the QBOE phase under solar minimum (SMIN) conditions while the smallest amplitudes and strongest static stabilities occur during the QBOW phase under solar maximum (SMAX) conditions. Conversely, when the QBO and solar forcings are opposed (QBOW/SMIN and QBOE/SMAX), the difference in occurrence rates becomes statistically insignificant. During the coming solar minimum, at least one additional winter in the QBOE/SMIN category should occur (possibly as early as 2017/2018) during which especially large MJO amplitudes are expected and an initial test of these results will be possible. Plain Language Summary An ongoing issue in climate science is the extent to which upper atmospheric processes, including solar forcing, can influence tropospheric climate. It has recently been shown that an internal oscillation of the stratosphere, the quasi-biennial oscillation, can modulate the amplitude and occurrence rate of intraseasonal climate oscillations in the tropical Pacific during northern winter. These intraseasonal oscillations, the most important of which is the 30-60day Madden-Julian oscillation, have significant derivative effects on climate outside of the tropics, including impacts on rainfall events over the continental United States. Here evidence is presented that the amplitude of the Madden-Julian oscillation during northern winter is also modulated by the 11year solar cycle. The modulation is such that amplitudes and occurrence rates are largest under solar minimum conditions when the quasi-biennial oscillation is in its easterly phase and smallest under solar maximum conditions when the quasi-biennial oscillation is in its westerly phase. However, the available time record (37.3years of satellite measurements) is limited. During the coming solar minimum, at least one additional winter in the solar minimum/easterly category should occur (possibly as early as 2017/2018) during which larger-than-average amplitudes are expected and an initial test of the proposed relationship will be possible.

No description available.

During the 21st century there has been a tremendous increase in grid-connected photovoltaic (PV) capacity globally, due to falling prices and introduction of economic incentives. PV systems are in most cases small-scale, installed on residential dwellings, which means that the power production is widely distributed and close to the end-user of electricity. In this licentiate thesis the distributed PV in the built environment is studied. A methodology for assessing short-term (sub-minute) solar variability was developed, which in the continuation of this PhD project could be used to study the aggregated impact on the local distribution grid from dispersed PV systems. In order to identify potential locations for PV systems in a future scenario, methodology was developed to assess the rooftop topography on both local level using LiDAR data and nationally through building statistics. Impacts on the distribution grid were investigated through a case study on a rural municipality in Sweden. It was found that the hosting capacity, i.e. the amount of PV power generation that can be integrated in the grid without exceeding certain power quality measures, is high, at least 30%. However, the hosting capacity on transmission level needs further investigation. As a first step a methodology was developed in order to model scenarios for hourly solar power generation, aggregated over wide areas, here applied to the whole Swedish power system. The model showed high correlation compared to PV power production reported to the Swedish transmission system operator (TSO). Furthermore, it was used to model scenarios of high PV penetration in Sweden, which give some indications on the impact on the power system, in terms of higher frequency of extreme ramps.

During the 21st century there has been a rapid increase in grid-connected photovoltaic (PV) capacity globally, due to falling system component prices and introduction of various economic incentives. To a large extent, PV systems are installed on buildings, which means they are widely distributed and located close to the power consumer, in contrast to conventional power plants. The intermittency of solar irradiance poses challenges to the integration of PV, which may be mitigated if properly assessing the solar resource. In this thesis, methods have been developed for solar variability and resource assessment in the built environment on both national and local level, and have been applied to grid integration studies. On national level, a method based on building statistics was developed that reproduces the hourly PV power generation in Sweden with high accuracy; correlation between simulated and real power generation for 2012 and 2013 were 0.97 and 0.99, respectively. The model was applied in scenarios of high penetration of intermittent renewable energy (IRE) in the Nordic synchronous power system, in combination with similar models for wind, wave and tidal power. A mix of the IRE resources was sought to minimise the variability in net load (i.e., load minus IRE, nuclear and thermal power). The study showed that a fully renewable Nordic power system is possible if hydropower operation is properly planned for. However, the contribution from PV power would only be 2-3% of the total power demand, due to strong diurnal and seasonal variability. On local level, a model-driven solar resource assessment method was developed based on low-resolution LiDAR (Light Detection and Ranging) data. It was shown to improve the representation of buildings, i.e., roof shape, tilt and azimuth, over raster-based methods, i.e., digital surface models (DSM), which use the same LiDAR data. Furthermore, the new method can provide time-resolved data in contrast to traditional solar maps, and can thus be used as a powerful tool when studying the integration of high penetrations of PV in the distribution grid. In conclusion, the developed methods fill important gaps in our ability to plan for a fully renewable power system.

Pacific salmon (Oncorhynchus spp.) production strongly influences the ecosystems, cultures and economies of the Northeast Pacific. Historical variability in population sizes is complex, reflecting natural and human drivers. The nature and extent of such ‘exogenous’ controls on salmon and their nursery ecosystems are poorly understood, a significant impediment to sustainable fisheries management. Novel applications of paleolimnology demonstrate that past sockeye salmon abundances and nursery system ecology can be reconstructed from lake sediments. This thesis focuses on employing these techniques to establish the forcing mechanisms underlying salmon population and ecosystem dynamics, and determine the effects and interactions of fisheries management. I provided the first reconstruction for a southern North American stock, which demonstrated the influences of both conspicuous (e.g. commercial fishery, main-stem damming) and uncertain human impacts (e.g. local damming) on endangered salmon declines. By reconstructing ecological variability at multiple trophic levels, I established that rehabilitative management (e.g. fish stocking) may have permanently altered nursery lake rearing capacity, a change potentially reinforced by recent atmospheric changes. This work highlights significant impediments to ongoing recovery efforts. I extended my analysis of salmon management by exploring the interactive impacts of exotic salmon stocking on a remote northern lake. I demonstrated the utility of long-term data in pre-emptively understanding the complex impacts of stocking by documenting the long-term trajectories in limnological conditions. Integrating modeling, limnological and paleolimnological analyses, I determined that climate change and salmon introductions compound to alter chemical, physical and biological lake variables, ultimately altering ecosystem structure and functioning. Finally I reconstructed salmon abundances over the past six millennia, the longest record and the first Canadian example to date, demonstrating salmon production is cyclical and far more variable than observed in the monitoring record. My analyses established that North Pacific salmon production is forced by ocean-atmospheric teleconnections ultimately linked to climatic variability in the tropical Pacific. Further analyses provided the first evidence for a possible solar forcing of Holocene salmon production on both orbital and higher frequency time scales. Cumulatively this research improves our understanding of the processes underlying variability in Pacific salmon and their natal ecosystems, important to ecologically-informed future management. / Thesis (Ph.D, Biology) -- Queen's University, 2008-09-27 02:41:54.576

abstract: Several short term exogenic forcings affecting Earth's climate are but recently identified. Lunar nutation periodicity has implications for numerical meteorological prediction. Abrupt shifts in solar wind bulk velocity, particle density, and polarity exhibit correlation with terrestrial hemispheric vorticity changes, cyclonic strengthening and the intensification of baroclinic disturbances. Galactic Cosmic ray induced tropospheric ionization modifies cloud microphysics, and modulates the global electric circuit. This dissertation is constructed around three research questions: (1): What are the biweekly declination effects of lunar gravitation upon the troposphere? (2): How do United States severe weather reports correlate with heliospheric current sheet crossings? and (3): How does cloud cover spatially and temporally vary with galactic cosmic rays? Study 1 findings show spatial consistency concerning lunar declination extremes upon Rossby longwaves. Due to the influence of Rossby longwaves on synoptic scale circulation, our results could theoretically extend numerical meteorological forecasting. Study 2 results indicate a preference for violent tornadoes to occur prior to a HCS crossing. Violent tornadoes (EF3+) are 10% more probable to occur near, and 4% less probable immediately after a HCS crossing. The distribution of hail and damaging wind reports do not mirror this pattern. Polarity is critical for the effect. Study 3 results confirm anticorrelation between solar flux and low-level marine-layer cloud cover, but indicate substantial regional variability between cloud cover altitude and GCRs. Ultimately, this dissertation serves to extend short term meteorological forecasting, enhance climatological modeling and through analysis of severe violent weather and heliospheric events, protect property and save lives. / Dissertation/Thesis / Ph.D. Geography 2013