Testing longwave radiation parameterizations under clear and overcast skies at Storglaciären, Sweden

Energy balance based glacier melt models require accurate estimates of incoming longwave radiation but direct measurements are often not available. Multi-year near-surface meteorological data from Storglaciären, Northern Sweden, were used to evaluate commonly used longwave radiation parameterizations in a glacier environment under clear-sky and all-sky conditions. Parameterizations depending solely on air temperature performed worse than those which include water vapor pressure. All models tended to overestimate incoming longwave radiation during periods of low longwave radiation, while incoming longwave was underestimated when radiation was high. Under all-sky conditions root mean square error (RMSE) and mean bias error (MBE) were 17 to 20 W m<sup>−2</sup> and −5 to 1 W m<sup>−2</sup>, respectively. Two attempts were made to circumvent the need of cloud cover data. First cloud fraction was parameterized as a function of the ratio, τ, of measured incoming shortwave radiation and calculated top of atmosphere radiation. Second, τ was related directly to the cloud factor (i.e. the increase in sky emissivity due to clouds). Despite large scatter between τ and both cloud fraction and the cloud factor, resulting calculations of hourly incoming longwave radiation for both approaches were only slightly more variable with RMSE roughly 3 W m<sup>−2</sup> larger compared to using cloud observations as input. This is promising for longwave radiation modeling in areas where shortwave radiation data are available but cloud observations are not

Total forcing number of the triangular grid

Let $T$ be a square triangular grid with $n$ rows and columns of vertices and $n$ an even number. A set of edges $Esubset E(T)$ completely determines perfect matchings on $T$ if there are no two different matchings on $T$ coinciding on $E.$ We establish the upper and the lower bound for the smallest value of $left| Eright| ,$ i.e. we show that begin{equation*} frac{5}{4}n^{2}-frac{21}{2}n+frac{41}{4}leq left| Eright| leq frac{5}{4}n^{2}+n-2 end{equation*}% and show that $left| Eright| /left| E(T)right|$ tends to $5/12$ when $n$ tends to infinity

Cloud and boundary layer interactions over the Arctic sea ice in late summer

Observations from the Arctic Summer Cloud Ocean Study (ASCOS), in the central Arctic sea-ice pack in late summer 2008, provide a detailed view of cloud- atmosphere-surface interactions and vertical mixing processes over the sea-ice environment. Measurements from a suite of ground-based remote sensors, near-surface meteorological and aerosol instruments, and profiles from radiosondes and a helicopter are combined to characterize a weeklong period dominated by low-level, mixed-phase, stratocumulus clouds. Detailed case studies and statistical analyses are used to develop a conceptual model for the cloud and atmosphere structure and their interactions in this environment. Clouds were persistent during the period of study, having qualities that suggest they were sustained through a combination of advective influences and in-cloud processes, with little contribution from the surface. Radiative cooling near cloud top produced buoyancy-driven, turbulent eddies that contributed to cloud formation and created a cloud-driven mixed layer. The depth of this mixed layer was related to the amount of turbulence and condensed cloud water. Coupling of this cloud-driven mixed layer to the surface boundary layer was primarily determined by proximity. For 75%of the period of study, the primary stratocumulus cloud-driven mixed layer was decoupled from the surface and typically at a warmer potential temperature. Since the near-surface temperature was constrained by the ocean-ice mixture, warm temperatures aloft suggest that these air masses had not significantly interacted with the sea-ice surface. Instead, backtrajectory analyses suggest that these warm air masses advected into the central Arctic Basin from lower latitudes. Moisture and aerosol particles likely accompanied these air masses, providing necessary support for cloud formation. On the occasions when cloud-surface coupling did occur, back trajectories indicated that these air masses advected at low levels, while mixing processes kept the mixed layer in equilibrium with the near-surface environment. Rather than contributing buoyancy forcing for the mixed-layer dynamics, the surface instead simply appeared to respond to the mixedlayer processes aloft. Clouds in these cases often contained slightly higher condensed water amounts, potentially due to additional moisture sources from below

Kvalitet tretiranja pri mehanizovanoj zaštiti uljane repice različitim rasprskivačima

Oil seed rape is one of three most important culture on the world. Production and protection of oil seed have some specific according to other cultures. When we speak of mechanization in oil seed production then we think on seed treatment with plant protection products. There is also need for protection against weeds, disease and insect. Sometime we need to protect oil seed rape against rodent using some rodenticide. In some moister condition it can be done desiccation with nonselective herbicide. Efficiency of pesticide application depends from application time and correct use and choice of machine and nozzles for application. This paper work analyze problems in oil seed rape protection from insects meligethes aeneus which cause damages and decrease of yield. Accent is on quality parameters analyses of using different type of nozzles for insecticides application in spring. The most important parameters which was analyze in this paper is leaf coverage. Treating was done with application rate 200 l/ha and three different type of nozzles. The lowest leaf coverage was achieved with standard nozzles Lechler LU12004, 36,79 %. Better coverage was achieved with nozzles IDK 12004, 37,24 % and the best overages was reached with 'Twin Jet' IDKT 04 nozzles. It was a coverage of 44,64 %.Uljana repica je veoma važna uljana kultura. Njena vegetacija počinje krajem leta i početkom jeseni, a završava se obično početkom leta naredne godine. Njeno gajenje i zaštita u odnosu na druge kulture, ima određenih specifičnosti. Mehanizovana hemijska zaštita uljane repice obuhvata uobičajene mere i dopunske mere, koje se sprovode ukoliko to uslovi zahtevaju. Uobičajeno je da se obavlja tretiranje semena repice fungicidima i insekticidima, dok se u prolećnom periodu u toku vegetacije, vrši zaštita od štetočina (sjajnik). Po potrebi izvodi se zaštita od korova, u nekim slučajevima, vrši se tretiranje protiv bolesti fungicidima u toku vegetacije. Ako period sazrevanja uljane repice prate česte kiše, može se sprovesti mehanizovana desikacija. U radu su dati rezultati istraživanja mehanizovane hemijske zaštite repice u toku vegetacije protiv štetočina (sjajnik). Tretiranje je obavljeno sa normom od 200 l/ha i tri vrste rasprskivača na istoj parceli u istim uslovima. Najniža pokrivenost površina, ostvarena je korišćenjem standardnih rasprskivača Lechler LU12004 (crveni) od 36, 79 %, nešto viša sa rasprskivačima IDK od 37,24 %, a značajno viša 44,64 % sa rasprskivačima sa duplim mlazom Twin Jet

Epitaxial growth and structural characterization of Pb(Fe1/2Nb1/2)O3 thin films

We have grown lead iron niobate thin films with composition Pb(Fe1/2Nb1/2)O3 (PFN) on (0 0 1) SrTiO3 substrates by pulsed laser deposition. The influence of the deposition conditions on the phase purity was studied. Due to similar thermodynamic stability spaces, a pyrochlore phase often coexists with the PFN perovskite phase. By optimizing the kinetic parameters, we succeeded in identifying a deposition window which resulted in epitaxial perovskite-phase PFN thin films with no identifiable trace of impurity phases appearing in the X-ray diffractograms. PFN films having thicknesses between 20 and 200 nm were smooth and epitaxially oriented with the substrate and as demonstrated by RHEED streaks which were aligned with the substrate axes. X-ray diffraction showed that the films were completely c-axis oriented and of excellent crystalline quality with low mosaicity (X-ray rocking curve FWHM<0.09). The surface roughness of thin films was also investigated by atomic force microscopy. The root-mean-square roughness varies between 0.9 nm for 50-nm-thick films to 16 nm for 100-nm-thick films. We also observe a correlation between grain size, surface roughness and film thickness.Comment: 13 Pages, 6 figures. To be published in J. Mag. Mag Mater. proceedings of EMRS200

Spiritual Struggles among Atheists: Links to Psychological Distress and Well-Being

Religious and spiritual struggles (R/S struggles)—tension or conflicts regarding religious or spiritual matters—have been robustly linked to greater psychological distress and lower well-being. Most research in this area has relied on samples consisting predominantly of participants who believe in god(s). Limited research has examined R/S struggles among atheists, generally conflating them with agnostics and other nontheists. This study investigated the prevalence of R/S struggles among atheists and compared atheists to theists in two samples (3978 undergraduates, 1048 Internet workers). Results of a multilevel model showed that atheists experience less demonic, doubt, divine, moral, and overall R/S struggles than theists, but similar levels of interpersonal and ultimate meaning struggles. Correlation and regression analyses among atheists demonstrated links between moral, ultimate meaning, and overall R/S struggles and greater distress (depression and anxiety symptoms) as well as lower well-being (life satisfaction and meaning in life). Even after controlling neuroticism, ultimate meaning struggles continued to predict lower well-being and higher distress across samples; moral struggles also predicted distress independently. This study demonstrates the relevance of R/S struggles to atheists and reinforces the applicability of previous results to atheist samples, but also highlights substantial differences between atheists and theists in certain R/S struggles

The Turbulent Structure of the Arctic Summer Boundary Layer During The Arctic Summer Cloud‐Ocean Study

The mostly ice covered Arctic Ocean is dominated by low‐level liquid‐ or mixed‐phase clouds. Turbulence within stratocumulus is primarily driven by cloud top cooling that induces convective instability. Using a suite of in situ and remote sensing instruments we characterize turbulent mixing in Arctic stratocumulus, and for the first time we estimate profiles of the gradient Richardson number at relatively high resolution in both time (10 min) and altitude (10 m). It is found that the mixing occurs both within the cloud, as expected, and by wind shear instability near the surface. About 75% of the time these two layers are separated by a stably stratified inversion at 100–200 m altitude. Exceptions are associated with low cloud bases that allow the cloud‐driven turbulence to reach the surface. The results imply that turbulent coupling between the surface and the cloud is sporadic or intermittent

The thermodynamic structure of summer Arctic stratocumulus and the dynamic coupling to the surface

The vertical structure of Arctic low-level clouds and Arctic boundary layer is studied, using observations from ASCOS (Arctic Summer Cloud Ocean Study), in the central Arctic, in late summer 2008. Two general types of cloud structures are examined: the "neutrally stratified" and "stably stratified" clouds. Neutrally stratified are mixed-phase clouds where radiative-cooling near cloud top produces turbulence that generates a cloud-driven mixed layer. When this layer mixes with the surface-generated turbulence, the cloud layer is coupled to the surface, whereas when such an interaction does not occur, it remains decoupled; the latter state is most frequently observed. The decoupled clouds are usually higher compared to the coupled; differences in thickness or cloud water properties between the two cases are however not found. The surface fluxes are also very similar for both states. The decoupled clouds exhibit a bimodal thermodynamic structure, depending on the depth of the sub-cloud mixed layer (SCML): clouds with shallower SCMLs are disconnected from the surface by weak inversions, whereas those that lay over a deeper SCML are associated with stronger inversions at the decoupling height. Neutrally stratified clouds generally precipitate; the evaporation/sublimation of precipitation often enhances the decoupling state. Finally, stably stratified clouds are usually lower, geometrically and optically thinner, non-precipitating liquid-water clouds, not containing enough liquid to drive efficient mixing through cloud-top cooling

Advances in understanding and parameterization of small-scalephysical processes in the marine Arctic climate system: a review

The Arctic climate system includes numerous highly interactive small-scale physical processes in the atmosphere, sea ice, and ocean. During and since the International Polar Year 2007–2009, significant advances have been made in understanding these processes. Here, these recent advances are reviewed, synthesized, and discussed. In atmospheric physics, the primary advances have been in cloud physics, radiative transfer, mesoscale cyclones, coastal, and fjordic processes as well as in boundary layer processes and surface fluxes. In sea ice and its snow cover, advances have been made in understanding of the surface albedo and its relationships with snow properties, the internal structure of sea ice, the heat and salt transfer in ice, the formation of superimposed ice and snow ice, and the small-scale dynamics of sea ice. For the ocean, significant advances have been related to exchange processes at the ice–ocean interface, diapycnal mixing, double-diffusive convection, tidal currents and diurnal resonance. Despite this recent progress, some of these small-scale physical processes are still not sufficiently understood: these include wave–turbulence interactions in the atmosphere and ocean, the exchange of heat and salt at the ice–ocean interface, and the mechanical weakening of sea ice. Many other processes are reasonably well understood as stand-alone processes but the challenge is to understand their interactions with and impacts and feedbacks on other processes. Uncertainty in the parameterization of small-scale processes continues to be among the greatest challenges facing climate modelling, particularly in high latitudes. Further improvements in parameterization require new year-round field campaigns on the Arctic sea ice, closely combined with satellite remote sensing studies and numerical model experiments.publishedVersio