Very short-term spatio-temporal wind power prediction using a censored Gaussian field

Wind power is a renewable energy resource, that has relatively cheap installation costs and it is highly possible that will become the main energy resource in the near future. Wind power needs to be integrated efficiently into electricity grids, and to optimize the power dispatch, techniques to predict the level of wind power and the associated variability are critical. Ideally, one would like to obtain reliable probability density forecasts for the wind power distributions. We aim at contributing to the literature of wind power prediction by developing and analysing a spatio-temporal methodology for wind power production, that is tested on wind power data from Denmark. We use anisotropic spatio-temporal correlation models to account for the propagation of weather fronts, and a transformed latent Gaussian field model to accommodate the probability masses that occur in wind power distribution due to chains of zeros. We apply the model to generate multi-step ahead probability predictions for wind power generated at both locations where wind farms already exist but also to nearby locations.     

Vegetation water sources in California's Sierra Nevada (USA) are young and change over time,a multi-isotope (δ18O, δ2H, 3H) tracer approach.

Sierra Nevada forests transpire a significant amount of California's water resources, sparking interest in applying forest management to improve California's water supply. Determining the source water of evapotranspiration enables forest managers to make informed decisions. To this end, a significant interest in critical zone science is to develop new methods to work across time scales to predict subsurface water storage and use. In this study, forest vegetation accessed young water and switched sources depending on availability, suggesting that forest drought vulnerability may depend on the range of water sources available (rain, snowmelt and deeply stored water). This finding also suggests that changes in transpiration rates may have immediate effects on water sources in close proximity to vegetation, and delayed effects on storage and runoff. New δ¹⁸O, δ²H and ³H data were used to track precipitation, runoff, evapotranspiration and storage through the critical zone seasonally, including seasons where evapotranspiration and snowmelt were in phase (winter snowmelt) and out of phase (seasonally dry summer). The main source of this headwater catchment's runoff is derived from its meadow saturated zone water, which was dominated by snowmelt. Water that originated as snowmelt contributed to transpiration, unless other sources, such as recent rain, became available. In cases where xylem δ¹⁸O and δ²H signatures matched those of deeper saturated zone water, ³H data showed that xylem water was distinctly younger than the deep saturated zone water. During 2016, which experienced relatively normal snowpack in winter and seasonally dry summer conditions, mean summer saturated zone water and vegetation water were similar in δ¹⁸O, −12.4 ± 0.04 ‰ and − 12.5 ± 0.3 ‰, respectively, but were distinctly different in ³H, 5.5 ± 0.2 pCi/L and 13.7 ± 1.1 pCi/L, respectively. While δ¹⁸O shows that vegetation and meadow saturated zone water have similar origins, ³H shows they have dissimilar ages.     

Toward Bayesian uncertainty quantification for forestry models used in the United Kingdom Greenhouse Gas Inventory for land use, land use change, and forestry

The Greenhouse Gas Inventory for the United Kingdom currently uses a simple carbon-flow model, CFLOW, to calculate the emissions and removals associated with forest planting since 1920. Here, we aim to determine whether a more complex process-based model, the BASic FORest (BASFOR) simulator, could be used instead of CFLOW. The use of a more complex approach allows spatial heterogeneity in soils and weather to be accounted for, but places extra demands on uncertainty quantification. We show how Bayesian methods can be used to address this problem.     

Observations of Diurnal Cycles Over a West African Meridional Transect: Pre-Monsoon and Full-Monsoon Seasons

We document and characterize the climatology of the diurnal cycles encountered along a West African transect during the pre-monsoon and full-monsoon periods. The meridional gradient in low-level properties is fundamental for the monsoon dynamics and here, for the first time, it is studied based on a large set of observations from the African Monsoon Multidisciplinary Analysis (AMMA) campaign. A detailed analysis of surface energy budget, boundary-layer structures and cloud occurrence is carried out to investigate the diurnal cycles of the low levels. A relatively weak meridional gradient of net radiation is observed during the pre-monsoon period, and a large gradient in sensible heat flux is found over the transect with values increasing from south to north. This, as well as the boundary-layer structures, partly explains the large contrasts in the diurnal amplitude of potential temperature and specific humidity along the transect. During the monsoon period, the atmospheric regimes drastically change involving strong interactions between the surface, atmosphere and clouds. The maximum in net radiation is shifted northwards, towards the Sahel, which potentially has a significant impact on the monsoon circulation. The sensible heat flux is considerably reduced and the diurnal amplitude is strongly damped, while the daytime boundary-layer growth decreases significantly in the Sahel related to changes in the balance of boundary-layer processes. These results highlight the contrasted diurnal cycle regimes encountered over West Africa under dry, moist and wet conditions. They provide observationally-based diagnostics to investigate the ability of models to handle the representation of the diurnal cycle over land.     

Spatial patterns and correlates of mortality due to selected non-communicable diseases among adults in South Africa, 2011

South Africa has a high prevalence of non-communicable diseases (NCDs) compared to other African countries. Government has predicted that NCDs will be a major threat of health in the country in the next 20–30 years and recommended a significant reduction in NCDs. This research studies spatial patterns of deaths resulting from chronic lower respiratory diseases (CLRD), malignant neoplasms of digestive organs (MNDO), diabetes mellitus (DM) and cerebrovascular diseases (CVD) among adults aged 15–69 years in 2011 at municipality level. The study uses secondary data from the civil registration system; population census; and supplementary information from the Business Register and a database of public health facilities. Moran’s Index, hot spot analysis and geographically weighted regression were applied to measure spatial autocorrelation of age-standardised death rates; to identify municipalities of high risk of deaths due to selected NCDs; and associated socio-economic and demographic factors. Clusters of high risk of deaths from selected NCDs were identified, with those for CLRD and MNDO mainly in the urban municipalities around the mid and western parts of the country while for DM and CVD they occurred mostly in the urban and rural north-eastern part, as well as in the urban municipalities of Northern Cape for CVD. Hot spots showed differential socio-economic and demographic risk factors in NCDs, which included sex, urbanisation, density of public hospitals; death occurrence in health facilities; smoking; asbestos roofing; mining and quarrying businesses. Findings highlight the importance of community-specific interventions and the need for a neighbourhood-based approach in tackling NCDs.     

http://www.sciencedirect.com/science/article/pii/S1674987111001344

The Rehai Geothermal Field,located in Tengcbong County,in central-western Yunnan Province, is the largest and most intensively studied geothermal held in China.A wide physicochemical diversity of springs(ambient to ~97℃;pH from≤.8 to≥9.3) provides a multitude of niches for extremophilic microorganisms.A variety of studies have focused on the cultivation,identification,basic physiology,taxonomy,and biotechnological potential of thermophilic microorganisms from Rehai.Thermophilic bacteria isolated from Rehai belong to the phyla Firmicutes and Deinococcus-Thenmts. Firmicutes include neutrophilic or alkaliphilic Anoxybacillus,Bacillus,Caldalkalibacillus.Caldanaerobacier, Laceyella,and Geobacillus,as well as thermoacidophilic Alicyclobacillus and Sulfobacillus. Isolates from the Deinococcus-Thermus phylum include several Meiothermus and Thennus species.Many of these bacteria synthesize thermostable polymer-degrading enzymes that may be useful for biotechnology. The thermoacidophilic archaea Acidianus.Melal/osp/utera.and Suljolobus have also been isolated and studied.A few studies have reported the isolation of thermophilic viruses belonging to Siphoviridae(TTSP4 and TTSPIO) and Fuselloviridae(STSVl) infecting Thennus spp.and Suljolobus spp..respectively.More recently,cultivation-independent studies using 16S rRNA gene sequences, shotgun metagenomics,or "functional gene" sequences have revealed a much broader diversity of microorganisms than represented in culture.Studies of the gene and mRNA encoding the large subunit of the ammonia monooxygenase(imioA) of ammonia-oxidizing Archaea(AOA) and the tetraether lipid erenarchaeol. a potential biomarker for AOA.suggest a wide diversity,but possibly low abundance,of thermophilic AOA in Rehai.Finally,we introduce the Tengchong Partnerships in International Research and Education(PIRE) project,an international collaboration between Chinese and U.S.scientists with the goal of promoting international and interdisciplinary cooperation to gain a more holistic and global view of life in terrestrial geothermal springs.     

The icy Galilean satellites: ultraviolet phase curve analysis

Ultraviolet disk-integrated solar phase curves of the icy galilean satellites Europa, Ganymede, and Callisto are presented, using combined data sets from the International Ultraviolet Explorer (IUE), Hubble Space Telescope (HST), and the Galileo Ultraviolet Spectrometer. Global, disk-integrated solar phase curves for all three satellites, in addition to disk-integrated solar phase curves for Europa's leading, trailing, jovian, and anti-jovian hemispheres, are modeled using Hapke's equations for 7 broadband UV wavelengths between 260 and 320 nm. The sparse coverage in solar phase angle, particularly for Ganymede and Callisto, and the noise in the data sets poorly constrain some of the photometric parameter values in the model. However, the results are sufficient for forming a preliminary relationship between the effects of particle bombardment on icy surfaces and photometric scattering properties at ultraviolet wavelengths. Callisto exhibits a large UV opposition surge and a surface comprised of relatively low-backward scattering particles. Europa's surface displays a dichotomy between the jovian and anti-jovian hemispheres (the anti-jovian hemisphere is more backward scattering), while a less pronounced hemispherical variation was detected between the leading and trailing hemispheres. Europa's surface, with the exception of the trailing hemisphere region, appears to have become less backscattering between the late-1970s-early-1980s and the mid-1990s. These results are commensurate with the bombardment history of these surfaces by magnetospheric charged particles.     

Vesta’s UV lightcurve: hemispheric variationin brightness and spectral reversal

Spectra of asteroid 4 Vesta obtained in October 1990 with the International Ultraviolet Explorer are reanalyzed and reinterpreted. A large portion of the eastern hemisphere (based on the prime meridian definition of Thomas et al., 1997a) is darker at UV wavelengths than much of the western hemisphere. The UV lightcurve is in contrast with the visible lightcurve, which shows that the eastern hemisphere is brighter than the western. These IUE spectra of Vesta thus may be evidence for the “spectral reversal,” first seen on the Moon by Apollo 17, where the visibly brighter lunar highlands are darker than the maria at far-UV wavelengths. This effect was linked to space weathering when it was noted (Wagner et al., 1987) that the spectral reversal appears in the laboratory spectra of lunar soils but not powdered lunar rocks.We investigate Vesta’s UV lightcurve and spectral reversal, and its possible connection with space weathering. The addition to grain coatings of small amounts of submicroscopic iron (SMFe) through vapor deposition causes drastic spectral changes at UV-visible wavelengths (Hapke, 2001), while the longer wavelength spectrum remains largely unaffected. Other laboratory results (e.g., Hiroi and Pieters, 1998) indicate that the UV-visible wavelength range is affected by simulated weathering processes in a manner similar to what is seen on Vesta. It is likely that Vesta has experienced relatively minor amounts of space weathering, as indicated by the spectral reversal, along with the subtle visible-near infrared weathering effects (e.g., Binzel et al., 1997).