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Abstract: Daily UK Met Office stratospheric assimilated data for the Northern and Southern Hemispheres, accumulated for the period from 2004 to 2012 and pressure range of 1000–0.1hPa, are used in this paper. The paper presents and thoroughly discusses spatial–temporal distributions of stationary planetary wave (SPW) amplitudes and phases, calculated on the basis of geopotential height, temperature, zonal and meridional wind data for zonal wave numbers 1 and 2 (SPW1 and SPW2). The climatological planetary wave amplitudes and phases are calculated by extracting waves from three types of data: daily, monthly mean and climatological monthly mean. It has been established that magnitude of amplitudes and height-latitude distribution of amplitudes of SPW1 and SPW2 depend on data processing method for all parameters. It has also been established that height-latitude distribution amplitudes and phases significantly differ for geopotential height, temperature, zonal and meridional wind and depend on wave number and hemisphere. However, height-latitude distributions of phases are little different from each other for the used methods of data processing. [Copyright &y& Elsevier]

Abstract The ionospheric Nighttime Winter Anomaly (NWA) is a feature observed in the Northern Hemisphere at the American and in the Southern Hemisphere at the Asian longitude sector under low solar activity conditions. Jakowski et al. (2015) analyzed ground-based GPS derived TEC and peak electron density data from radio occultation measurements on Formosat-3/COSMIC satellites and confirmed the persistence of the phenomenon. Further, they assumed that Mid-latitude Summer Nighttime Anomaly (MSNA) and related special anomalies such as the Weddell Sea Anomaly (WSA) and the Okhotsk Sea Anomaly (OSA) are closely related to the NWA via enhanced wind-induced uplifting of the ionosphere. The aim of this paper is to study the factors causing these anomalies and also to investigate if these anomalies are re-produced by IRI. The results show that IRI model does include the NWA effect, though at a different longitude and could be improved for better predictions. The IRI-2016 model does show WSA in TEC but not in NmF2. Further, the IRI-2016 model could clearly predict the OSA both in NmF2 and TEC. [ABSTRACT FROM AUTHOR]

Abstract In this paper we investigate response of the total ozone column to energetic electron precipitation (EEP) observed by bremsstrahlung effect. The list of EEP events was prepared by members of the balloon experiments of the Lebedev Physical Institute. Here we used superposed epoch analysis and the days with EEP events are registered during winter (November–February) and summer (June–August) months from 1970 to 2012 were chosen as key dates. This period corresponds approximately to three solar cycles. Data of the total ozone column were collected by single coherent total ozone dataset, called the Multi Sensor Reanalysis (MSR). A long series of data of the total ozone column is allowed us to study the response of ozone content to 90 winter and 103 summer EEP events. The obtained ozone sensitivity to the events of energetic electron precipitation is clearly pronounced during local winters in the high latitudes of the Northern and Southern Hemispheres (60–80 NH and 60–80 SH). In the high latitudes of the Northern Hemisphere, during winter months, the total ozone content can be reduced by up to 10 DU after energetic electron precipitation with minimum observed on the first day after EEP events. Response of the total ozone, over high latitudes of the Northern Hemisphere, to EEP events can be opposite during summer months. [ABSTRACT FROM AUTHOR]

Abstract: This is the first paper to report a detailed comparison between ground based measurements of cloud enhanced ultraviolet (UV) radiation at sites located in both hemispheres. The measurements were undertaken at a Northern Hemisphere site (at the campus of the University of Girona in Spain) and a Southern Hemisphere site (campus of the University of Southern Queensland, Toowoomba, Australia). These sites were chosen as they have both simultaneous sky camera and solar radiation (including UV) measurement campaigns operating for at least 5 years over the same time period. Although hemispheric comparisons of UV radiation are not new, this paper focuses on a study of enhancements, including a comparison of the frequency of occurrence and associated cloud types, at the locations with differing climatology. It is found that although there are commonalities between the sites, such as the correlation of the frequency of enhancements with larger solar zenith angle (SZA) both at Girona and Toowoomba, there are differences too, e.g. the frequency of occurrence of the enhancements, and the type of clouds that produce most enhancements (cirrus at Girona, cumulus at Toowoomba). It is suggested that this is due to the differences in latitude coupled with a large amount of Cirriform cloud, especially corresponding to large SZA, at Girona. Possible explanations for this major difference were examined, with the most likely hypothesis relating to multiple scattering due to Cirriform cloud and the subsequent effect on UV radiation on a horizontal surface at large SZA. [Copyright &y& Elsevier]

Abstract: Radioxenon isotopes play a major role in confirming whether or not an underground explosion was nuclear in nature. It is then of key importance to understand the sources of environmental radioxenon to be able to distinguish them from those of a nuclear explosion. Nuclear power plants were long thought to be the main emitters of these noble gases. Based on new, more sensitive technologies with higher time resolution, recent studies have shown that regions with nuclear facilities have a background of few mBq/m3 of 133Xe with short spikes up to few hundred mBq/m3. These spikes could not in general be explained by normal nuclear power plant operations. Based on several years of measurements, combined with advanced atmospheric transport model results, this paper shows that the main source of radioxenon observations are strong and regular batch releases from a very limited number of radiopharmaceutical facilities in the northern and southern hemisphere. These releases can be up to several orders of magnitude above those attributed to nuclear power plants. This paper reviews the possible production processes of radiopharmaceutical isotopes during which xenon radioisotopes are created. Different production possibilities (with high and low enriched uranium targets) and release scenarios are studied and the total releases are compared with long distance environmental measurements. Further, the ratios of the different radioxenon isotopes are analysed and discussed. [Copyright &y& Elsevier]

Measurements from TOMS and UARS-HALOE are used to estimate the effects of energetic particle precipitation (EPP) over the stratosphere during two geomagnetic storms occurred in November of the years 2003 and 2004. The EPP couples the solar wind to the Earth’s atmosphere and indirectly to the Earth’s climate. Due to particle precipitation, the ionization and dissociation increase, and create odd nitrogen (NO x ) and odd hydrogen (HO x ) in the upper atmosphere, which can affect ozone chemistry. In this paper, statistically significant variation in total ozone content at middle latitudes of the Southern Hemisphere is observed. The variations depend on the intensity of geomagnetic disturbances and the geomagnetic longitude. A significant variation in NO x concentration at altitudes from 30 to 50 km is observed from the profiles analysis. [ABSTRACT FROM AUTHOR]

The stratospheric temperature trend plays an important role in distinguishing between the climate systems responses to natural and human induced changes. A linear trend of monthly mean temperature from the NCEP/NCAR reanalysis dataset for both Hemispheres with 2.5° step in latitude and longitude for the period 1979–2011, were calculated on this paper. Four different stratospheric heights: 10 hPa, 30 hPa, 50 hPa, and 70 hPa were analyzed. The observed trend pattern changes with height as expected. The area of negative trends increases when we go up in the stratosphere. Lower and middle stratosphere shows positive trends, in a section of the latitudinal band between 50° S and 60° S. As we go down the stratosphere these positive trends are smoother. At 10 hPa all trends are negative. In Southern Hemisphere at 30 hPa significant negative trends at low middle latitudes were observed. These results were compared with others, obtained by models and observations. [ABSTRACT FROM AUTHOR]

In this paper, we developed a two-dimensional ionospheric assimilation model that assimilates the observations of peak electron density of F2-layer (NmF2) and the peak height of F2-layer (hmF2) derived from five ionosonde stations along the 120°E meridian, using three-dimensional variation techniques (3DVAR) based on a physics-based ionosphere theoretical model. The assimilation system can well produce the assimilated results along the 120°E meridian plane by using the data of NmF2 and hmF2 at five ionosonde stations from Mohe (52.0°N) to Sanya (18.3°N). The root mean square error (RMSE) between the analysis results of the assimilation model and the ionosonde observations is much lower than that between the results from international reference ionosphere (IRI) and the ionosonde observations. In addition, we carried out the assimilation test by taking the IRI results as the observations to check the assimilated results in the regions without observations. The assimilated result in the southern hemisphere (RMSE=0.29) is much worse than that in the northern hemisphere (RMSE=0.10) because no observations in the southern hemisphere were used. If the data derived from the four ionosonde stations in Australia are used, the assimilated result in the southern hemisphere would be much more accurate. In addition to NmF2 and hmF2, the assimilation model can also adjust the total electron content (TEC). The RMSE between the TEC after assimilation and the observed GPS TEC is much lower than that between the TEC from the IRI model and the observed GPS TEC. [ABSTRACT FROM AUTHOR]

This paper reviews the status of our understanding of the Earth's annual, global mean energy balance, the hemispheric energy balances and the symmetry observed about the equator, and explores the influence of latitudinal changes of energy both on the annual mean and seasonal transports of energy from low latitudes to higher latitudes. Based on the best available information we show that our planet continues to be out of balance with additional heat being added to it at the rate of 0.6 ± 0.4 Wm − 2 . This heat appears to be taken up primarily by the oceans of the SH and perhaps mostly equatorward of 37 S. The nature of the adjustments applied to our best estimates of individual, annual mean fluxes of energy to produce a balance are described and the results of applying a more formal constraint for these adjustments are discussed. The energy balances of the Southern and Northern Hemispheres are then shown to be practically identical which in turn suggests the transport of energy across the equator in the net is close to zero. In fact the hemispheres are not identically symmetrical with the SH being slightly out of balance absorbing the additional heat and transporting a small amount of net heat across the equator to the balanced NH. The symmetry in absorbed solar and the near symmetry in OLR are remarkable in their own right and are a result of the effects of clouds both on solar reflection and OLR that act to offset land–ocean interhemispheric differences. We then demonstrate important interhemispheric seasonal influences on the heat transported to the winter pole that conspire to make these seasonal transports lopsided. This asymmetry is a direct result of the eccentricity of the Earth's orbit that induces larger energy losses from the southern winter hemisphere. This in turn produces a latitudinal asymmetry in the location of on the tropical trough zone, a region from which energy is always moved to the winter pole, requiring it be located deeper into the NH. [ABSTRACT FROM AUTHOR]

Subjective visual interpretation of MODIS Quick-Look imagery has proven useful in characterising dust source geomorphology and dust event frequency over diverse areas, but is limited by the small temporal sampling window of polar orbiting platforms, and obscuration by cloud. In this paper we seek to quantify the inevitable under-reporting of dust events in Quick-Look imagery, via a three-year case study over the Lake Eyre Basin (LEB), the largest dust source in Australia and the southern hemisphere. Dust event identification from MODIS imagery is compared with the level of dust mobilization inferred from measurements of near-surface aerosol made by a continuously-operating integrating nephelometer, located at the AeroSpan/AERONET station at Tinga Tingana in the Strzelecki Desert, adjacent to major dust sources in the LEB. The analysis indicates a major upward revision in the overall dust event frequency by ~ 72%, including a doubling of the incidence of major dust outbreaks. The intensity of missed events increases toward late afternoon and evening, although without a net day-night bias. These factors suggest the potential of new geostationary sensors and the analysis of night-time polar orbiting imagery in improving the reporting of dust mobilization over active dust-source regions. For the LEB, the corrections are crucial in understanding not only the seasonal distribution of dust mobilization, but its interannual variability and climatology. [ABSTRACT FROM AUTHOR]

Analysis of long-term solar data from different observatories is required to compare and confirm the various level of solar activity in depth. In this paper, we study the north–south asymmetry of monthly mean sunspot area distribution during the cycle-23 and rising phase of cycle-24 using the data from Kodaikanal Observatory (KO), Michelson Doppler Imager (MDI) and Solar Optical Observing Network (SOON). Our analysis confirmed the double peak behavior of solar cycle-23 and the dominance of southern hemisphere in all the sunspot area data obtained from three different resources. The analysis also showed that there is a 5–6 months time delay in the activity levels of two hemispheres. Furthermore, the wavelet analysis carried on the same data sets showed several known periodicities (e.g., 170–180 days, 2.1 year) in the north–south difference of sunspot area data. The temporal occurrence of these periods is also the same in all the three data sets. These results could help in understanding the underlying mechanism of north–south asymmetry of solar activity. [ABSTRACT FROM AUTHOR]

Using an earth system model of intermediate complexity (EMIC), the McGill Paleoclimate Model-2 (MPM-2), this paper examines the climatic biogeophysical effects of afforestation in the southern hemisphere (SH) with a focus on land–atmosphere interactions and the modeling influence of the dynamic ocean in the background of the earth system. Increased forest cover affects the albedo feedback and the supply of water, which in turn influences temperature. These changes largely control the net impact of the SH afforestation based on latitudinal band. In response to afforestation in 0–15°S and 0–40°S, the local surface air temperature significantly increases at a maximum value around 5°S during autumn. This warming is attributed to decreased land surface albedo dominating over enhanced precipitation which is resulted from increased tree cover. Forest expansions in 15–30°S and 30–40°S induce diminished land surface albedo and precipitation locally, leading to a warming around 25°S during spring and a warming around 35°S in winter, respectively. The maximum differences in the modeled responses of afforestation on latitude band basis are seen to be 7–10 times larger for the same season. Our results show that capturing how and where biogeophysical changes due to forest expansion warm a specific region requires an accurate global simulation of afforestation geographically. This provides potential for further improving detection and attribution of regional afforestation effects. Furthermore, a dynamic ocean simulation results in a warming compared with a fixed one over most forcing originating areas in response to afforestation. We demonstrate that unless the dynamic ocean is considered we risk influenced conclusions regarding the drivers of temperature changes over regions of afforestation. [ABSTRACT FROM AUTHOR]

South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene. [ABSTRACT FROM AUTHOR]

Abstract: The paper is focused on ionospheric response to occasional magnetic disturbances above selected ionospheric stations located at middle latitudes of the Northern and Southern Hemisphere under extremely low solar activity conditions of 2007–2009. We analyzed changes in the F2 layer critical frequency foF2 and the F2 layer peak height hmF2 against 27-days running mean obtained for different longitudinal sectors of both hemispheres for the initial, main and recovery phases of selected magnetic disturbances. Our analysis showed that the effects on the middle latitude ionosphere of weak-to-moderate CIR-related magnetic storms, which mostly occur around solar minimum period, could be comparable with the effects of strong magnetic storms. In general, both positive and negative deviations of foF2 and hmF2 have been observed independent on season and location. However positive effects on foF2 prevailed and were more significant. Observations of stormy ionosphere also showed large departures from the climatology within storm recovery phase, which are comparable with those usually observed during the storm main phase. The IRI STORM model gave no reliable corrections of foF2 for analyzed events. [Copyright &y& Elsevier]

Abstract: Changes in the strength and position of Southern Hemisphere westerly winds during the Last Glacial cycle have been invoked to explain both millennial and glacial–interglacial climate fluctuations. However, neither paleo models nor paleodata agree on the magnitude, or even the sign, of the change in wind strength and latitude during the most studied glacial period, the Last Glacial Maximum (LGM), compared to the recent past. This paper synthesizes paleo-environmental data that have been used to infer changes in LGM winds. Data compilations are provided for changes in terrestrial moisture, dust deposition, sea surface temperatures and ocean fronts, and ocean productivity, and existing data on Southern Hemisphere ocean circulation changes during the LGM are summarized. We find that any hypothesis of LGM wind and climate change needs to provide a plausible explanation for increased moisture on the west coast of continents, cooler temperatures and higher productivity in the Subantarctic Zone, and reductions in Agulhas leakage around southern Africa. Our comparison suggests that an overall strengthening, an equatorward displacement, or no change at all in winds could all be interpreted as consistent with observations. If a single cause related to the southern westerlies is sought for all the evidence presented, then an equatorward displacement or strengthening of the winds would be consistent with the largest proportion of the observations. However, other processes, such as weakening or poleward shifts in winds, a weakened hydrological cycle, extended sea-ice cover, and changed buoyancy fluxes, cannot be ruled out as potential explanations of observed changes in moisture, surface temperature, and productivity. We contend that resolving the position and strength of westerly winds during the LGM remains elusive based on data reconstructions alone. However, we believe that these data reconstructions of environmental conditions can be used in conjunction with model simulations to identify which processes best represent westerly wind conditions during the LGM. [Copyright &y& Elsevier]

Abstract: Yang et al. [1] quantified vertical velocity and upward mass fluxes in tropical lower stratosphere based on radiative heating rate calculations using the Fu-Liou radiation model along with 8-year Southern Hemisphere Additional Ozonesondes balloon-borne measurements of temperature and ozone and cryogenic frost-point hygrometer measured water vapor. The impact of tropospheric clouds on stratospheric heating rates was considered using cloud distributions from the International Satellite Cloud Climatology Project. Since the radiative heating rate in the lower stratosphere can be as small as 0.1–0.2K/day, an accurate radiative heating rate calculation including all radiatively active species is required. In this paper, we revisit the calculations in Yang et al. [1] by developing a line-by-line radiative transfer model (LBLRTM-D4S) for multiple scattering atmospheres. We consider the cloud impact using the cloud fields based on active lidar and radar observations from CALIPSO and CloudSat so that the quantification of upward mass fluxes in tropical lower stratosphere can be extended to tropical upper troposphere. The annual mean mass fluxes and vertical velocities from LBLRTM-D4S are ∼14kgm−2 day−1 and 0.77mms−1, respectively, at 120hPa (15.5km), and ∼1.2kgm−2 day−1 and 0.13mms−1 at 60hPa (19.5km). We examine the accuracy of three commonly used efficient radiation models including Fu-Liou, RRTM, and SBDART in estimating tropical upward mass fluxes against the LBLRTM-D4S results. [Copyright &y& Elsevier]

Abstract: The recent increase in food prices has revealed that climate, combined with an expanding population and a widespread change in diet, may result in an end to an era of predictable abundance of global cereal crops. The objective of this paper is to estimate changes of agriculturally-relevant growing season parameters, including the start of the season, length of the growing period and the position of the height or peak of the season, in the primary regions with rainfed agriculture during the past 26years. Our analysis found that globally, 27% of cereal crop areas have experienced changes in the length of the growing season since 1981, the majority of which had seasons that were at least 2.3days per year longer on average. We also found both negative and positive trends in the start of season globally, with different effects of changing temperature and humidity being isolated depending on the country and region. We investigated the correlation between the peak timing of the growing season and agricultural production statistics for rain fed agriculture. We found that two thirds of the countries investigated had at least 25% of pixels with crop production that behaved differently than expected from the null hypothesis of no correlation. The results show that variations in the peak of the growing season have a strong effect on global food production in these countries. We show that northern hemisphere countries and states appear to have improved model fit when using phenological models based on humidity while southern hemisphere countries and states have improved model fit by phenological models based on accumulated growing degree days, showing the impact of climate variability during the past two and a half decades. [Copyright &y& Elsevier]

Abstract: With global warming water issue is becoming a mean problem in areas of the south hemisphere where raining is decreasing considerably. As a result, preserving such resource is becoming a crucial task facing the authorities. One of the main ways of preservation is making the water pipelines network as safe as possible from any damages involving lose of water around urban areas in particular those situated within areas prone to seismicity. For this purpose, a method to assess the seismic vulnerability of water pipelines was developed and implemented in a Geographical Information System (GIS), allowing larger water supply network to be covered and studied. This method is based on the identification of the parameters that have an influence on the behaviour of pipelines. Each parameter having a coefficient that represent its influence on the behaviour of the structure, the product of these parameters represent the seismic vulnerability of the section pipe under study. As a result, a proposed classification is obtained allowing the determination of a safe section (green colour), an unsafe section (red colour) and an intermediate situation (orange colour). For a proposed application of the method, a case study for a town in suburb of Algiers is presented within this paper. It concerns the town of Blida. The results are given in the following sections. [Copyright &y& Elsevier]

Abstract: One prominent feature of solar wind—Mars interaction has to do with the presence of strong crustal magnetic fields, especially, in the southern hemisphere. This physical property has set Mars apart from Venus as far as the kinetic effect in detail. In this paper, we review briefly the recent particles-and-fields measurements at Mars in connection to the auroral activity driven by magnetic field reconnection between the crustal magnetic fields and the interplanetary fields. It is suggested that the subsolar ENA (energetic neutral atoms) jets discovered by the NPD instrument of Mars Express could be resulting from charge exchange effect of the shocked solar wind protons at the magnetopause-like regions of the Martian mini-magnetospheres and at the cusp regions of the crustal magnetic fields. It also means that ENA and LENA (low energy neutral atom) detectors could be important experiments for diagnostics of the auroral process unique to Mars, which might contribute to the overall atmospheric loss budget. [Copyright &y& Elsevier]

The purpose of this paper is to explore whether international income transfers can improve or worsen the global level of biodiversity and global social welfare by changing the relative contributions to biodiversity protection and to agricultural production. Because of the public good nature of biodiversity, Warr's neutrality theorem suggests that such transfers may have no effects at all (Warr, 1983). A model is developed, based on the simplifying assumption that northern countries have little biodiversity whereas southern countries are endowed with natural capital in the form of (generally unspoilt) biodiversity-rich land. Southern countries allocate optimally land and capital to two competing productive activities, agriculture and eco-tourism. When transfers are organized from the North to the South, we show that Warr's neutrality theorem collapses. Transfers can either reduce or increase the natural capital in the South, depending on some empirically verifiable hypotheses concerning the characteristics of the eco-tourism and agricultural production functions. In addition, we demonstrate that welfare improvements can be obtained even with reductions in the level of biodiversity. [Copyright &y& Elsevier]

Abstract: This paper presents results from the Storm-Time Ionospheric Correction Model (STORM) validation for selected Northern and Southern Hemisphere middle latitude locations. The created database incorporated 65 strong-to-severe geomagnetic storms, which occurred within the period 1995–2007. This validation included data from some ionospheric stations (e.g., Pruhonice, El Arenosillo) that were not considered in the development or previous validations of the model. Hourly values of the F2 layer critical frequency, foF2, measured for 5–7days during the main and recovery phases of each selected storm were compared with the predicted IRI 2007 foF2 with the STORM model option activated. To perform a detailed comparison between observed values, medians and predicted foF2 values the correlation coefficient, the root-mean-square error (RMSE), and the percentage improvement were calculated. Results of the comparative analysis show that the STORM model captures more effectively the negative phases of the summer ionospheric storms, while electron density enhancement during winter storms and the changeover of the different storm phases is reproduced with less accuracy. The STORM model corrections are less efficient for lower-middle latitudes and severe geomagnetic storms. [Copyright &y& Elsevier]

Abstract: Medical isotope production facilities (MIPF) have recently been identified to emit the major part of the environmental radioxenon measured at many globally distributed monitoring sites deployed to strengthen the radionuclide component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime. Efforts to raise a global radioxenon emission inventory revealed that the yearly global total emission from MIPF’s is around 15 times higher than the total radioxenon emission from nuclear power plants (NPP''s). Given that situation, from mid 2008 until early 2009 two out of the ordinary hemisphere-specific events occured: 1) In the Northern hemisphere, a joint temporary suspension of operations of the three largest MIPF''s made it possible to quantify the effects of the emissions related to NPP’s. The average activity concentrations of 133Xe measured at a monitoring station close to Freiburg, Germany, went down significantly from 4.5 ± 0.5 mBq/m3 to 1.1 ± 0.1 mBq/m3 and in Stockholm, Sweden, from 2.0 ± 0.4 mBq/m3 to 1.05 ± 0.15 mBq/m3. 2) In the Southern hemisphere the only radioxenon-emitting MIPF in Australia started up test production in late November 2008. During eight test runs, up to 6.2 ± 0.2 mBq/m3 of 133Xe was measured at the station in Melbourne, 700 km south-west from the facility, where no radioxenon had been observed before, originating from the isotopic production process. This paper clearly confirms the hypothesis that medical isotope production facility are at present the major emitters of radioxenon to the atmosphere. Suspension of operations of these facilities indicates the scale of their normal contribution to the European radioxenon background, which decreased two to four fold. This also gives a unique opportunity to detect and investigate the influence of other local and long distance sources on the radioxenon background. Finally the opposing effect was studied: the contribution of the start-up of a renewed radiopharmaceutical facility to the build up of a radioxenon background across Australia and the Southern hemisphere. [Copyright &y& Elsevier]

Abstract: The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the most stable in amplitude and phase eastward propagating diurnal and semidiurnal tides with zonal wavenumbers 2 and 3 derived from the SABER/TIMED temperatures for full 6years (January 2002–December 2007). The tidal results are obtained by an analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally travelling, zonally symmetric and stationary) are simultaneously extracted from the satellite data. It has been found that the structures of the eastward propagating diurnal tides with zonal wavenumbers 3 and 2 change from antisymmetric with respect to the equator below ∼85km height, to more symmetric above ∼95km. The seasonal behavior of the DE3 is dominated by annual variation with maximum in August–September reaching average (2002–2007) amplitude of ∼15K, while that of the DE2 by semiannual variation with solstice maxima and with average amplitude of ∼8K. These tides revealed some interannual variability with a period of quasi-2years. The seasonal behavior of the eastward propagating semidiurnal tide with zonal wavenumber 2 in the southern hemisphere (SH) is dominated by annual variation with maximum in the austral summer (November–January) while that in the northern hemisphere (NH) by semiannual variation with equinoctial maxima. The SE2 maximizes near 115km height and at latitude of ∼30° reaching an average amplitude of ∼6K. The seasonal behavior of the eastward propagating semidiurnal tide with zonal wavenumber 3 in both hemispheres indicates a main maximum during June solstice and a secondary one during December solstice. The tide maximizes near 110–115km height and at a latitude of ∼30° reaching an average amplitude of ∼4.8K in the SH and ∼4K in the NH. The tidal structures of the two eastward propagating semidiurnal tides are predominantly antisymmetric about the equator. [Copyright &y& Elsevier]

Events around the world this year celebrate the bicentenary of the birth of Charles Darwin (1809–1882) and the sesquicentenary of publication of his most important work, The Origin of Species (Darwin 1859). The associated plethora of books and papers now appearing to commemorate Darwin''s work continue the traditional emphasis on his zoological and geological contributions. There has been some recent attention directed towards Darwin''s relatively unsung but significant accomplishments as a botanist. Here, we bring together a review of Darwin''s botanical discoveries and experiments and relevant aspects of his geological investigations, with a focus on the Southern Hemisphere. This is a relatively unexplored aspect of Darwin''s contributions that yields some new insights meriting future research. [Copyright &y& Elsevier]

Abstract: This paper proposes a model of serpentinization of the Southern martian crust that may explain the topographic dichotomy, the absence of an associated free-air gravity anomaly and the presence of strong magnetic anomalies in the Southern Hemisphere. The thermodynamical conditions for serpentinization were likely met in the lithosphere during the Noachian period. This process may have decreased the density in the Southern crust and created the topographic dichotomy. Different reactions of serpentinization that can form magnetite have been considered. Assuming an intense magnetic field (core dynamo), we obtain chemical remanent magnetizations that are in the order of the estimates deduced from martian magnetic anomaly studies. The pertinence and the implications of our model concerning the early thermal evolution of Mars are discussed, with emphasis on the intensity of the paleo-magnetic field. [Copyright &y& Elsevier]

Abstract: GPS technique is widely used to study the global structure and dynamics of the ionosphere. This paper presents data on the occurrence of large-scale ionospheric irregularities observed at Antarctic stations McMurdo-MCM4 (−78N, 167E, Φ =80°), Casey-CAS1 (−66N, 110E, Φ =80°), Mawson-MAW1 (−68N, 63E, Φ =71°), and Davis-DAV1 (−69N, 78E, Φ =75°) in 2001. The irregularities caused strong Total Electron Content fluctuations. The intensity of TEC fluctuations was estimated with the ROT parameter and rate of TEC index (ROTI) expressed in TECU/min. Storm-time development of TEC fluctuations are presented for two geomagnetic active periods: June and September 2001. Data on temporal variations in TEC along individual satellites passes were also analyzed. Polar patches were associated with deep TEC fluctuations as the TEC enhancements were 2–10 times larger than the background, whereas the TEC increased by 10–50 TECU in about 5–10min. The duration of such structures is 10–20min. At 4–5h interval, 3–5 strong and some weak patches were detected. The activity of patches depends to a low degree only on the magnetic activity index Kp. The intensity of TEC fluctuations increases during substorm activity. Diurnal, seasonal dependence, and longitudinal features of the occurrence of polar patches are also presented in the report. [Copyright &y& Elsevier]

Abstract: Chironomid paleoecology in north-temperate regions has made tremendous progress over the past decade, but studies in tropical and Southern Hemisphere regions remain relatively scarce. Reasons for this imbalance are (1) incomplete taxonomic knowledge of chironomid faunas outside Europe and North America, (2) a scarcity of ecological data on local species and genera that might confer bio-indicator value to them, and (3) logistic difficulties hampering the lake surveying necessary to develop paleoenvironmental calibration data sets. Thus far, most chironomid paleoecology in tropical and Southern Hemisphere regions has relied on an indicator-species approach, combining autecological information on local species of which larval morphology is known with the traditional ecological typology of chironomid genera transferred from the Holarctic region. This paper reviews work accomplished to date in tropical and temperate South America, Australia, Africa, and New Zealand, including studies on various families of non-chironomid Diptera with diagnostic fossils. Research has focused mostly on late-Glacial and Holocene climate reconstruction, less on tracing past human disturbance of aquatic ecosystems and their drainage basins. Quantitative chironomid-based paleoenvironmental reconstruction has so far been done only in Australia and Africa. These studies compensated for the lack of traditional surface-sediment calibration data sets, nowadays often the main source of quantitative information on species ecological optima and tolerances, by maximally exploiting archival species-distribution data based on live collections of adult and/or larval midges. This stimulated efforts to achieve trustworthy species-level identification of fossil chironomid remains, and, as a result, the taxonomic resolution of paleoecological studies in Australia and Africa is higher on average than that achieved in European and North American studies. [Copyright &y& Elsevier]

Abstract: Polar Mesosphere Summer Echoes (PMSE) were detected above the high-latitude station Davis, Antarctica (68.6°S) using a 55MHz atmospheric radar during the 2003–2004 austral summer. In this paper, we examine the characteristics of southern hemisphere PMSE events observed during the interval 19 November to 16 February 2004. Coincident satellite-SABER temperature measurements and ground-VHF radar backscatter observations revealed that PMSE existed for mesosphere temperatures in the range ∼124.4–134.7K. An examination of the horizontal wind field using collocated VHF and MF radar measurements showed that PMSE also occurred during conditions of westward zonal winds and equatorward meridional winds. A remarkable correlation was evident between the onset (end) of the austral summer PMSE season and equatorward (poleward) flowing meridional mesospheric winds observed for the 19 November 2003 (16 February 2004), respectively. We present evidence of a semidiurnal influence of the meridional and zonal tides on the occurrence, intensity, and altitude of PMSE events. The effects of tidal, gravity and planetary waves on PMSE events are also considered. [Copyright &y& Elsevier]

Abstract: This paper gives the yearly 85Kr emissions of all known reprocessing facilities, which are the main sources of 85Kr in the atmosphere since 1945, for the years 1945 until 2000. According to this inventory 10,600PBq (Peta=1015) of 85Kr have been globally emitted from the year 1945 until the end of 2000. The global atmospheric inventory at the end of the year 2000 amounts to 4800PBq. These emissions have been incorporated into the ECHAM4 atmospheric general circulation model as point sources. Monthly mean model results are compared with measurements made at different locations and times. The influence of each source on the measured concentrations at various locations is studied. The calculated concentrations are found to give reasonably good agreement with the observations, indicating that the emission inventory is realistic. Although, at all northern hemispheric observation sites the model tends to slightly overestimate the concentrations. A possible reason for this overestimation can be found in model features (coarse resolution in time and space). The most prominent discrepancy that is consistently repeated at all northern hemispheric stations occurs in the early 1990s. This could most likely be related to an overestimate of sources. Possibly, the Russian emissions declined earlier than assumed in the current database. Another discrepancy between observations and simulations indicating an incompleteness of the release data is found at some southern hemispheric sites. The variability of their observations could only be explained by regional sources. However, several spikes occur after 1992 when no reprocessing facility is known to be in operation in the southern hemisphere. Production of isotopes for radiopharmaceuticals like technetium-99m from highly enriched uranium is the most likely explanation. [Copyright &y& Elsevier]

A ‘ghost’ whistler group is one that follows a similar whistler group after a fixed and repeating time interval. This phenomenon was observed at Marion Island in the southern hemisphere. During a ninety minute period 11 whistler groups were followed, after a time interval of 600 ms, by ‘ghost’ groups. An explanation of this non-random time delay is that a component of the first group, on its way to the southern hemisphere resonates with counter-streaming electrons, close to the equatorial plane, causing some of them to diffuse in pitch angle and precipitate into the northern atmosphere. Entering the atmosphere the electrons trigger by some means, a second atmospheric discharge that produces the ‘ghost’ group. If this explanation is correct then the time delay between a ‘ghost’ and its whistler should vary with latitude. In this paper we calculate these time delays as a function of latitude. If ‘ghosts’ are found with delays that corresponded to these values it would be a powerful verification of the theory. [Copyright &y& Elsevier]

Determining the magnitude of primary production (PP) in a changing ocean is a major research challenge. Thousands of estimates of marine PP exist globally, but there remain significant gaps in data availability, particularly in the Southern Hemisphere. In situ PP estimates are generally single-point measurements and therefore we rely on satellite models of PP in order to scale up over time and space. To reduce the uncertainty around the model output, these models need to be assessed against in situ measurements before use. This study examined the vertically-integrated productivity in four water-masses associated with the East Australian Current (EAC), the major western boundary current (WBC) of the South Pacific. We calculated vertically integrated PP from shipboard 14 C PP estimates and then compared them to estimates from four commonly used satellite models (ESQRT, VGPM, VGPM-Eppley, VGPM-Kameda) to assess their utility for this region. Vertical profiles of the water-column show each water-mass had distinct temperature–salinity signatures. The depth of the fluorescence-maximum ( f max ) increased from onshore (river plume) to offshore (EAC) as light penetration increased. Depth integrated PP was highest in river plumes (792±181 mg C m −2 d −1 ) followed by the EAC (534±116 mg C m −2 d −1 ), continental shelf (140±47 mg C m −2 d −1 ) and cyclonic eddy waters (121±4 mg C m −2 d −1 ). Surface carbon assimilation efficiency was greatest in the EAC (301±145 mg C (mg Chl-a) −1 d −1 ) compared to other water masses. All satellite primary production models tested underestimated EAC PP and overestimated continental shelf PP. The ESQRT model had the highest skill and lowest bias of the tested models, providing the best first-order estimates of PP on the continental shelf, including at a coastal time-series station, Port Hacking, which showed considerable inter-annual variability (155–2957 mg C m −2 d −1 ). This work provides the first estimates of depth integrated PP associated with the East Australian Current in temperate Australia. The ongoing intensification of all WBCs makes it critical to understand the variability in PP at the regional scale. More accurate predictions in the EAC region will require vertically-resolved in situ productivity and bio-optical measurements across multiple time scales to allow development of other models which simulate dynamic ocean conditions. [ABSTRACT FROM AUTHOR]

Abstract: This study provides new information about the composition, diversity and zoogeography of abyssal polychaetes in the little-studied South Eastern Atlantic (Angola Basin). During the austral winter of 2000, twenty-five box core samples (total area sampled 6m2) were taken along a 500-km transect in five work areas at depths exceeding 5000m. A total of 1047 individuals representing 86 species belonging to 32 families was collected. Well over half the polychaetes (58 species; 67%) appear to be new to science, with the highest number of new species among the Cirratulidae, Paraonidae, Phyllodocidae, Ampharetidae, Opheliidae, and Spionidae. Eight of these new species were among the 16 dominant species in the deep Angola Basin whereas, 32 species (37%) were considered to be rare with only 1–2 individuals collected. Species accumulation curves did not level off at a fixed number of species, indicating that diversity would increase with additional sampling. Polychaete community assemblages among box core samples were highly variable. Ten of the known species are biogeographically widespread outside the Angola Basin whereas five appear to be restricted to the deep Atlantic. Two species have only been recorded in the Southern Ocean, and one in the southern hemisphere. Twenty (35%) of the species considered to be new to science were also found in samples from the deep Southern Ocean, whereas eight of the known species found in the Angola Basin have not been reported from the Southern Ocean to date. Surface deposit feeders and carnivores were the dominant functional groups both in terms of number of individuals and number of species. Necessary steps to further our knowledge of the little-known abyssal ecosystem are discussed. [Copyright &y& Elsevier]