OHP–APT 2002 gravity wave campaign: waves,turbulence and forecasts

In July 2002, a multi-sensor campaign was conducted in southern France to investigate the hypothesized connection between gravity waves and optical turbulence. A generalized scidar (GS) was mounted on the 1.93 m diameter telescope at l’Observatoire de Haute-Provence (OHP). The GS provides continuous profiles of optical turbulence with 300 m vertical resolution from telescope altitude up to 25 km. Thermosondes, which provide in situ measurement of optical turbulence by measuring temperature variance, were launched at the OHP site and at a site approximately 20 km west-northwest of OHP. Gravity wave activity was deduced from temperature and wind velocity measured by radiosondes, which are part of the thermosonde system. In this paper, gravity waves were analyzed using techniques for simple two-dimensional mountain waves, with only fair results. Mesoscale models were run at moderately high resolution for the period. The forecasts were analyzed for wave activity, and a post processor model was used to diagnose the optical turbulence. Mountain waves were evident in the forecast, but quantitative comparison showed the forecast to be inadequate in predicting wave strength. The forecast optical turbulence was in fair agreement with measurements with notable exceptions. This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. Presented at the Turbulence and Waves in Stably Stratified Atmospheric Shear Flows: Measurements, High Resolution Simulations and Numerical Prediction Challenges Conference, 13–15 September 2004, Lighthill Institute of Mathematical Sciences, University College London, London, UK.     

Responses of nymphs of desert locust,Schistocerca gregaria to volatiles of plants used as rearing diet

Summary Gregarious nymphs of the desert locust,Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae) were more attracted to volatiles from mechanically damaged food plants used for rearing than to either the undamaged or damaged food plants not used as diet in Y-tube olfactometer assays. Comparative analysis of the volatile emissions from plants used for rearing and food plants not used for rearing,e.g. Sorghum bicolor, Pennisetum clandestinum, Schouwia thebaica, wheat (Triticum sp., var. Nyangumi),Zygophyllum simplex, Heliotropium undulatum andTribulus terrestris was carried out by GC, GC-EAD and GC-MS. Significant quantitative and qualitative differences were found in the volatile emissions and olfactory responses of nymphs in GC-EAD assays. Up to 33 compounds were identified in volatiles of the plants of which 9 evoked EAGs. EAG-active components included common green leaf compounds (E)-2-pentenal, (E)-2-hexenal, 4-methyl-3-pentenal, (E)-3-hexenyl acetate, (Z)-3-hexenyl acetate, (Z)-2-hexenyl acetate, (Z)-3-hexen-1-ol and (Z)-2-hexen-1-ol. (Z)-3-Hexenyl butyrate and (Z)-3-hexenyl isovalerate were detected in stimulatory amounts only in the volatiles ofS. thebaica. (E, Z)-2,6-Nonadienal was detected as a component in the volatiles ofT. terrestris and was highly stimulatory. In EAG assays with seven common green leaf volatiles, (Z)-3-hexenyl acetate was most stimulatory while hexanal was the least. No significant differences were recorded between antennal responses of males and females to the tested compounds. These results are discussed with regard to current hypotheses on host plant recognition through detection of their airborne volatiles and the learning behaviour by nymphs ofS. gregaria.     

Exposure to metals (Ca,K, Mn) and road salt (NaCl) differentially affect development and survival in two model amphibians

ABSTRACT

Human activity has led to widespread chemical alteration of natural environments. Aquatic ecosystems are especially susceptible to chemical changes, including those caused by runoff and invasive species. Here, we examined the effects of water chemistry, specifically sodium chloride as well as three metals (Ca, K, and Mn) known to differ between native and invasive wetland plant species’ leaf tissues, on the development of two model amphibians: the native Northern leopard frog, Lithobates pipiens, and the non-native African clawed frog, Xenopus laevis. We exposed frog eggs to metal treatment solutions and measured time to hatching (TTH), and following hatching, we exposed tadpoles to a lethal concentration of sodium chloride and recorded time to death (TTD). We found that increasing metal concentrations generally resulted in acceleration of TTH for Xenopus tadpoles, but had no effect on leopard frogs. However, increasing metal concentrations (Ca, Mn) increased leopard frog tadpole susceptibility to NaCl (decreased TTD), while increasing metal concentrations (Ca, K) generally resulted in decreased Xenopus tadpole susceptibility to NaCl. Overall, our data suggest that invasive amphibians may be more tolerant to chemical changes than native amphibians, including those driven by the introduction of invasive plant species.     

The Impact of Variation in Stopover Habitat Quality on Migrant Rufous Hummingbirds

We examined the impact of variation in habitat quality on migrating Rufous Hummingbirds ( Selasphorus rufus ) in the California Sierra Nevada. As do other migratory species, these birds depend on "stopover" habitats en route for feeding and replenishing depleted energy stores. During seven years of study, the quality of the stopover habitat (assessed in terms of the density of nectar food resources) varied widely due to natural variation in flowering. In years when stopover habitat quality was poor, incoming body masses were low and stopover durations were long. Population densities of migrant hummingbirds at the study site were coupled to habitat quality both within and among years. These observations demonstrate important effects of stopover habitat variation on the physiological, behavioral, and population ecology of migrating hummingbirds. High-quality stopover habitats are critical links between breeding and wintering areas for many species, and their preservation should be considered an essential component of strategies aiming to conserve migratory bird populations.     

A laser flash photolysis study of the decay of SO4- and Cl2- radical anions in the presence of Cl- in aqueous solutions

The rate constant for the reaction of sulphate radical (SO4-) with Cl- has been determined using laser photolysis, at 248 nm, of peroxodisulphate anions to produce the radicals and time resolved optical absorption of the transient species (at 450 or 480 nm for SO4- and 350 nm for Cl2-) for the kinetic determinations. The experiments were performed, in the absence of added sulphate, as a function of temperature and ionic strength and yielded (at an ionic strength of 0.0157 M): kIV = (9.90+/-0.16) x 10(9) exp((-7.12+/-2.0) kJ mol(-1)/RT) M(-1) s(-1), where the errors reflect the 2sigma statistical error. This reaction produces Cl2-, the formation and decay of which were also monitored allowing a determination of the rate constant of its second-order self-recombination reaction which gave k = (6.50+/-1.40) x 10(8) M(-1) s(-1) at 293 K and zero ionic strength.     

Partitioning of mercury in the North Saskatchewan River

Mercury levels in fish, water and sediments were determined during 1982 along a 600 km stretch of the North Saskatchewan River (NSR) in the province of Alberta. Migratory fish species such as goldeye, walleye and sauger in the NSR were found to contain total mercury levels ranging from 0.104 to 1.553 mg/kg ($\text{mean}\text{≧ 0.5}\text{mg}\text{/}\text{kg}$). Northern pike, white sucker, longnose sucker and northern redhorse sucker had total mercury levels ranging from 0.003 to 1.003 mg/kg (mean < 0.5 mg/kg) Regression analysis of the data revealed that neither the sex of the fish nor the location of the sampling site contributed significantly to the mercury burden in fish in the entire study section of the river. Sediment analysis showed a low and more or less uniform concentrations of mercury in Alberta (≦0.1 mg/kg). The total mercury in NSR water averaged 0.09 μg/L in upstream Edmonton and was found to elevate in downstream NSR (0.22 μg/L) near industrial discharge sites and agricultural runoff areas (mean = 0.20 μg/L). Calculated partition coefficients seem to group the fish into two categories, (i) goldeye, walleye and sauger (bioconcentration factor [BCF] =3?3.7×10³ and (ii) northern pike, longnose sucker, white sucker and northern redhorse sucker (BCF=1.2?1.8×10³).     

Emission inventory on company level: lessons from Russia

Developing a transparent,accurate greenhouse gas (GHG) emissionsinventory is the first step toward buildingan effective GHG management system. Todate, GHG inventories have been conductedprimarily at national levels. Theinternationally accepted inventorymethodology developed by theIntergovernmental Panel on Climate Change(IPCC) is oriented to countrywideinventories. The electricity company RAOUESR is the largest single corporateemitter of GHG in the Russian Federation. The company is responsible for about 1/3 ofRussia's CO₂ emissions; RAO's fossil fuelemissions are comparable to the fossil fuelemissions of the United Kingdom. The GHGinventory prepared by RAO is the first suchcorporate emissions inventory undertaken ina non-OECD country. In this article wepresent a detailed independent examinationof the methodology RAO applied for theinventory. We identify the most importantsources of uncertainty and we estimate theuncertainty. The main conclusion of theindependent review is that the methodologyutilized by RAO and the informationsupporting the methodology are reliable andpresent a reasonably accurate company-widepicture of RAO's CO₂ emissions. The shareof other greenhouse gases is negligiblysmall and we did not focus on this fractionof RAO's GHG emissions. As a next step, RAOmay wish to conduct more precisefacility-by-facility inventories in orderto create a robust GHG emission managementsystem.