ABSTRACT This paper summarizes the hydrological variability in eastern California (central Sierra Nevada) for the past 3000 yr based on three distinct paleoclimate proxies, δ 18 O, total inorganic carbon (TIC), and magnetic susceptibility (chi). These proxies, which are recorded in lake sediments of Pyramid Lake and Walker Lake, Nevada, and Mono Lake and Owens Lake, California, indicate lake-level changes that are mostly due to variations in Sierra Nevada snowpack and rainfall. We evaluated lake-level changes in the four Great Basin lake systems with regard to sediment-core locations and lake-basin morphologies, to the extent that these two factors influence the paleoclimate proxy records. We documented the strengths and weaknesses of each proxy and argue that a systematic study of all three proxies together significantly enhances our ability to characterize the regional pattern, chronology, and resolution of hydrological variability. We used paleomagnetic secular variation (PSV) to develop paleomagnetic chronostratigraphies for all four lakes. We previously published PSV records for three of the lakes (Mono, Owens, Pyramid) and developed a new PSV record herein for Walker Lake. We show that our PSV chronostratigraphies are almost identical to previously established radiocarbon-based chronologies, but that there are differences of 20–200 yr in individual age records. In addition, we used eight of the PSV inclination features to provide isochrons that permit exacting correlations between lake records. We also evaluated the temporal resolution of our proxies. Most can document decadal-scale variability over the past 1000 yr, multidecadal-scale variability for the past 2000 yr, and centennial-scale variability between 2000 and 3000 yr ago. Comparisons among our proxies show a strong coherence in the pattern of lake-level variability for all four lakes. Pyramid Lake and Walker Lake have the longest and highest-resolution records. The δ 18 O and TIC records yield the same pattern of lake-level variability; however, TIC may allow a somewhat higher-frequency resolution. It is not clear, however, which proxy best estimates the absolute amplitude of lake-level variability. Chi is the only available proxy that records lake-level variability in all four lakes prior to 2000 yr ago, and it shows consistent evidence of a large multicentennial period of drought. TIC, chi, and δ 18 O are integrative proxies in that they display the cumulative record of hydrologic variability in each lake basin. Tree-ring estimations of hydrological variability, by contrast, are incremental proxies that estimate annual variability. We compared our integrated proxies with tree-ring incremental proxies and found a strong correspondence among the two groups of proxies if the tree-ring proxies are smoothed to decadal or multidecadal averages. Together, these results indicate a common pattern of wet/dry variability in California (Sierra Nevada snowpack/rainfall) extending from a few years (notable only in the tree-ring data) to perhaps 1000 yr. Notable hydrologic variability has occurred at all time scales and should continue into the future.

Abstract Melting of snow and ice contributes a large amount of water to the streamflow in the Satluj River. During the winter season, there is low base flow in the river as compared to spring and summer. Temperature is one of the key factors which directly impacts snow and ice melting throughout the year. A substantial amount of snowmelt only occurs when all the snow in a pack reaches isothermal condition. It is therefore very important to know the duration of impact of temperature on snowmelt runoff. Since the Himalayas have very few stations observing hydrological as well as meteorological conditions, it is difficult to validate the snowmelt models and examine changes in small-scale features in river basins of the region. The present study examines the annual cycle and interannual variability of runoff in the Satluj Basin in the western Himalayas and documents the impact of temperature on snowmelt runoff of Satluj River using daily in situ data for the period 1982–2005. A multivariate regression model using precipitation and surface temperature has been developed to predict the discharge of Satluj River at a daily scale. It is seen that after every warm phase and cold phase of temperature, the impact persists for around one month and affects the snowmelt runoff during January, February and March at lower- and higher-elevation stations such as Bhakra and Kasol, respectively. The effect of a large fall and rise in temperature is noticed on snowmelt runoff measured at all the discharge stations, while a small temperature change does not affect the observed discharge at all the stations. The remote sensing and reanalysis data are consistent with in situ data in the basin, and there is no major change in peak month of discharge or the amplitude during two different periods at Rampur gauge station.

Abstract Radon ( 222 Rn) has been highlighted by a number of authors as a significant public health concern. For example, it is the second most significant cause of lung cancer after tobacco smoking ( c. 1000–2000 and 21 000 deaths per year in the UK and USA, respectively), yet a very high proportion of the general public appears to be unaware of the risk. This chapter deals with topical radon issues, such as: radon in the workplace; radon in homes; exposure to radon during leisure activities; radon and water; measurement and monitoring; seasonal correction; remediation; cancer risks; cost–benefit analysis and cost-effectiveness; mapping; future policies; and further research. This assessment of the state of radon research is focused on the UK as an example of a country where radon has been on the governmental agenda since the late 1970s, but also highlights radon issues throughout the world in, for example, the USA, Europe and Asia.

Abstract The majority of radon measurements in the built environment are made over sub-year periods and are then generally seasonally corrected (i.e. scaled by an appropriate seasonal correction factor (SCF)) to estimate the annual average radon concentration. SCFs are statistically derived and assume an underlying annual cycle, reflecting the widely observed seasonal variation in indoor radon concentrations. In the UK, Public Health England has pioneered the calculation and use of a national SCF set using an annual sinusoidal model for variations in radon concentration and averaging across the entire country. To test the validity of that model, a 4 year record of weekly radon data from four houses in Brixworth (Northamptonshire, UK) was analysed in conjunction with corresponding weather data for the period from a nearby weather station. The radon data showed a statistically significant annual cycle comprising both annual sinusoidal and second harmonic (i.e. 6 month period) terms. Two sets of SCFs were calculated: first, using a conventional annual sinusoidal model that explained 21.2% of the variance in the radon data; and, secondly, a second harmonic term was included in the model that explained 24.6% of the variance. This represents an improvement of 3.4 percentage points (15.9%) and, thus, will result in better SCFs.

Tehran, the capital of the Islamic Republic of Iran, is a case of unplanned urban development. About 12% of Iranians are Tehran dwellers, and geology plays a major role in their environment. The city is located in northern Iran in the foothills of the Alborz Mountains. Sediments underlying the city are composed of coarse (northern part of Tehran) to very fine (southern part of Tehran) sandstone, siltstone, and mudstone with interbeds of gravels and pebbles in various proportions up to a depth of 1600 m. The early settlers were attracted to the area because there were bountiful springs and kanats (or qanats, an underground channel with vertical access shafts used to transport water from an aquifer under a hill to the surface without the need for pumping). The inharmonious geomorphology has strongly influenced the local climate for Tehran, with northern portions of the city in the humid mountains and southern portions in the desert. As development and expansion of the urban area continue, there will be increasing demand for natural resources and services such as water supply and construction material, land-use changes, increasing pollution, and exposure to geological hazards. In this article, we use surface and subsurface geological data to highlight the geological constraints on sustainable urban growth and management.

Abstract Central Skåne (Scania) in southern Sweden hosts evidence of extensive Jurassic volcanism in the form of mafic volcanic plugs and associated volcaniclastic deposits that entomb well-preserved macro-plant and spore–pollen assemblages. Palynological assemblages recovered from the Höör Sandstone are of Hettangian–Pliensbachian age and those from the overlying lahar deposits are dated as Pliensbachian–early Toarcian (?). Palynomorph assemblages from these units reveal significantly different ecosystems, particularly with respect to the gymnospermous components that represented the main canopy plants. Both palynofloras are dominated by osmundacean, marattiacean and cyatheacean fern spore taxa but, whereas the Höör Sandstone hosts abundant Chasmatosporites spp. pollen produced by plants related to cycadophytes, the volcanogenic deposits are dominated by cypress family pollen ( Perinopollenites ) with an understorey component rich in putative Erdtmanithecales (or possibly Gnetales), and collectively representing vegetation of disturbed habitats. Permineralized conifer wood attributed to Protophyllocladoxylon sp., belonging to plants that probably produced the abundant Perinopollenites grains, is abundant in the volcanigenic strata, and shows sporadic intraseasonal and multi-year episodes of growth disruption. Together with the relatively narrow but marked annual growth rings, and the annual and mean sensitivity values that span the complacent–sensitive domains, these features suggest growth within Mediterranean-type biomes subject to episodic disturbance.