Alkaline phosphatase activity in the western English Channel: Elevations induced by high summertime rainfall

Alkaline phosphatase activity (APA) was determined in bulk particulate material and in a single-cell (ELF) assay at station L4 in the western English Channel during the summer of 2007. Throughout this period, the UK experienced its heaviest summertime rainfall since records began in 1914; with the result that riverine run-off into coastal waters was also elevated relative to long-term averages. Between May and August 2007, three distinct periods of elevated river run-off were observed which resulted in salinity minima at L4 on days 141, 190 and 232. An extended period of high river run-off between days 170 and 210 was responsible for decreases in near-surface salinity at L4 from 35.2068 to a minimum on day 190 of 34.7422. This contributed to the development of haline stratification which supported the development of an intense bloom of the centric diatom Chaetoceros debelis, with maximum observed chlorophyll a concentration of 8.69 μg l⁻¹. Minima in salinity, and maxima in chlorophyll concentration on day 190 were coincident with a peak in river-derived dissolved inorganic nitrogen (DIN) of 1.9 μmol l⁻¹ which was >5 times greater than the summertime mean and 24 times the concentrations experienced at L4 on weeks immediately before and after. There was no accompanying increase in dissolved inorganic phosphorus (DIP), and the DIN:DIP ratio increased to 49. With the inherent phosphorus stress that this caused, rates of APA increased from <4 to 42.4 nmolP l⁻¹ h⁻¹. ELF analysis on day 197 identified two taxa actively expressing alkaline phosphatase: the dinoflagellate Prorocentrum micans and ciliate Tiarana sp.     

Changing growing season observed in Canada

It is theoretically interesting for climate change detection and practically important for agricultural producers to know whether climate change has influenced agroclimatic conditions and, if so, what the potential impacts are. We present analyses on statistical differences in means and variances of agroclimatic indices between three 30-year periods in the 20th century (i.e., 1911–1940, 1941–1970 and 1971–2000). We found many occurrences of statistically significant changes in means between pairs of the three 30-year periods. The findings consistently support agroclimatic trends identified from trend analysis as an earlier growing season start and an earlier end to spring frost (SF), together with an extended growing season, more frost-free days (FFD) and more available heat units were often found in the later 30-year periods as compared to the earlier ones. In addition, this study provides more detailed quantitative information than the trend signals for the practical interests of agricultural applications. Significant changes were detected for SF and FFD at a much larger percentage of stations between the latter two 30-year periods (1941–1970 vs. 1971–2000) as compared to the earlier two periods (1911–1940 vs. 1941–1970). In contrast, changes in variances of the selected agroclimatic indices were less evident than changes in their means, based on the percentage of stations showing significant differences. We also present new climate averages of the selected agroclimatic indices that can be useful for agricultural planning and management.     

Biological soil crust development and its topsoil properties in the process of dune stabilization, Inner Mongolia, China

This study was undertaken at Horqin Sand Land, Inner Mongolia, Northern China. Field samples of biological soil crusts (BSCs) and underlying topsoil (0–5 cm under BSC) were taken in areas of different dune stabilization stages, and their physicochemical properties were analyzed, including particle size distribution, bulk density, organic matter, nitrogen, phosphorus, electrical conductivity (EC), pH, and CaCO₃ content. The results revealed that semi-mobile dunes, semi-fixed dunes and fixed dunes had developed a physical crust, algae crust and moss crust, respectively. The thickness, hardness, water content, fine fraction and nutrient contents of BSCs were gradually increasing along the dune stabilization gradient. Meanwhile, BSC establishment and development enhanced the bulk density, silt and clay content, and nutrients of the topsoil under it, in an increasing tend from semi-mobile dune to fixed dune. Organic matter concentrations and other nutrients in the 0–5 cm topsoil layer under BSCs were significantly higher compared to unconsolidated soil (control). Moreover, there were strong significant positive correlations between topsoil and BSCs’ organic matter, total nitrogen, available nitrogen, available phosphorus, CaCO₃, and <0.05 mm particle content, suggesting that BSCs have an influence on some of the properties of the underlying topsoil.     

Least-squares harmonic estimation of the tropopause parameters using GPS radio occultation measurements

In order to investigate temporal variations of the tropopause parameters, Least-Squares Harmonic Estimation (LS-HE) is applied to the time series of the tropopause temperatures and heights derived from Global Positioning System Radio Occultation (GPS RO) atmospheric profiles of CHAMP, GRACE and COSMIC missions from January 2006 until May 2010 in different regions of Iran. By applying the univariate LS-HE to the completely unevenly spaced time series of the tropopause temperatures and heights, annual and diurnal components are detected together with their higher harmonics. The multivariate LS-HE estimates the main periodic signals, particularly diurnal and semidiurnal cycles, more clearly than the univariate LS-HE. Mixing in the values of the tropopause height and temperature is seen to occur in winter at lower latitudes (around 30°) as a result of subtropical jet, and in summer at higher latitudes (36°–42°) as an effect of subtropical high. A bimodal pattern is observed in the frequency histograms of the tropopause heights, in which the primary modes for the southern and northern parts of Iran correspond to subtropical and extratropical heights, respectively.     

Who will win the green race? In search of environmental competitiveness and innovation

As the world considers greener forms of economic growth, countries and sectors are beginning to position themselves for the emerging green economy. This paper combines patent data with international trade and output data in order to investigate who the winners of this “green race” might be. The analysis covers 110 manufacturing sectors in eight countries (China, Germany, France, Italy, Japan, South Korea, UK and the US) using date for the period 2005–2007. We identify three success factors for green competitiveness at the sector level: the speed at which sectors convert to green products and processes (measured by green innovation), their ability to gain and maintain market share (measured by existing comparative advantages) and a favourable starting point (measured by current output). We find that the green race is likely to alter the present competitiveness landscape. Many incumbent country-sectors with strong comparative advantages today lag behind in terms of green conversion, suggesting that they could lose their competitive edge. Japan, and to a lesser extent Germany, appear best placed to benefit from the green economy, while other European countries (Italy in particular) could fall behind. However, the green economy is much broader than the few flagship sectors on which the debate tends to focus, and each country has its niches of green competitiveness.     

Consistent scale-dependency of future increases in hourly extreme precipitation in two convection-permitting climate models

Climate Dynamics - Convection-permitting models (CPMs) have been proven successful in simulating extreme precipitation statistics. However, when such models are used to study climate change,...     

Ionospheric threat simulation for GNSS using the Spirent hardware signal simulator

Ionospheric disturbances present a considerable hazard to single-frequency satellite navigation systems for airborne users. We discuss our implementation of three ionospheric threat models in the DLR “multi-output advanced signal test environment for receivers” global navigation satellite system simulator, which is based on Spirent GSS 7780/7790 signal generator. These threat models include the standard front-based threat model developed for the integrity assessment of ground-based augmentation systems (GBAS), a simplified plasma bubble model, and ionospheric scintillation, which can be combined with either of the two previously mentioned models. These effects can now straightforwardly be simulated at the German Aerospace Center’s research facilities. As an example, we simulate a GBAS ground facility with code–carrier divergence monitoring, affected by an ionospheric front, and we show the results of a simulation with coincidental occurrence of a plasma bubble and scintillation with an S ₄ index of 0.4.     

Efficiency, Equity and Effect: a case study on virtual water consumption characteristics

Scarcity of water is the key factor restricting the growth of social economy.The virtual water theory provides a new way to solve the problem of water scarcity.For this paper,we have calculated the virtual water consumption of each household,grouped by income,of Gansu province for 1992-2005.Then we advanced the indicator of virtual water with per-unit-of-consumption expenditure to analyze the efficiency of virtual water consumption.Additionally,we recurred to the diversity theory advanced by Ulanowicz,which is broadly employed by ecologists and biologists,to analyze the characteristics of virtual water consumption.As a result,the virtual water consumption of each group decreased yearly from 1992 to 2005,on the whole;decreasing proceeded slower during the period of 1992-1997 than during 1998-2005.Per-unit-consumption expenditure of virtual water for each group represents the same characteristics,on the whole,as virtual water consumption.The largest variation of this indicator exists in the group of the lowest income,which ranges from 1.58 to 0.18 m3/Yuan.yr;whereas the least exists in the highest income group,which is 0.58 to 0.07 m3/Yuan.yr.The virtual diversity indicator increased year by year,and the change of this indicator in 1992-1997 was more obvious than in 1998-2005.Finally,from this study we find that,in view of virtual water,we can save water by means of changing consumption patterns and increasing consumption diversity,but without degrading the quality of living and reducing the demands of living.When the problem of water scarcity becomes more and more serious in Gansu of China,this suggestion becomes more and more important.The consumption,the role of guiding production produce,is very important.An unsustainable consumption pattern is the main factor causing the deterioration of the world environment,especially in a developing country.The sustainable consumption is the only way to develop human beings and achieve the economical sustainable economics.     

Long-term variability in mesopause region temperatures over Fort Collins, Colorado (41°N, 105°W) based on lidar observations from 1990 through 2007

During 1990–2007, there were 894 lidar observations of nocturnal mesopause region temperatures over Fort Collins, Colorado. In an earlier analysis with data to April 1997, an unexpected episodic warming, peaking in 1993 with a maximum value over 10 K, was reported and attributed to the Mount Pinatubo eruption in June 1991. With all data, long-term temperature trends from a 7-parameter linear regression analysis including solar cycle effect and long-term trends leads to a cooling of as much as 6.8 K/decade at 100 km, consistent with some reported observations but larger than model predictions. Including the observed episodic warming response in an 11-parameter nonlinear regression analysis reduces the maximum long-term cooling trends to 1.5 K/decade at 91 km, with magnitude and altitude dependences consistent with the prediction of two models, Spectral Mesosphere/Lower Thermosphere Model (SMLTM) and Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA). In addition, the mid-latitude middle-atmospheric response to solar flux variability in Thermosphere–Ionosphere-Energetics and Dynamics (TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperatures is presented.