Miracle-dz/UniFAR-FTUs huggingface dataset:
Future snowfall in western and central Europe projected with a high‐resolution regional climate model ensemble

Snowfall frequency and intensity are influenced strongly by climate change. Here we separate the basic frequency change resulting from a gradually warming climate, from the intensity changes, by focusing on snowfall on days where the mean temperature is below freezing (Hellmann days). Using an ensemble of simulations, obtained with the high‐resolution regional climate model KNMI‐RACMO2 driven by the EC‐EARTH global climate model and RCP4.5 and RCP8.5 forcing scenarios, we show that in addition to the strong decrease in the number of Hellmann days, also a substantial reduction in the mean Hellmann‐day snowfall can be expected over large parts of western and central Europe. Moreover, seasonal snowfall extremes display trends that are comparable or even larger. Projected intensity reductions are locally as large as −30% per degree warming, thus being in sharp contrast to mean winter precipitation, which increases in most future climate scenarios. Exceptions are the high Alps and parts of Scandinavia, which may see an increase of up to +10% per degree warming.
Multiple Convection Patterns and Thermohaline Flow in an Idealized OGCM

Abstract This paper investigates how multiple steady states arise in an ocean general circulation model, caused by the fact that many different convection patterns can be stable under the same surface boundary conditions. Two alternative boundary conditions are used in the experiments: classical mixed boundary conditions and a diffusive atmospheric heat balance combined with fixed salt fluxes. In both cases, transitions between different quasi-steady convection patterns can be triggered by briefly adding fresh water at convection sites. Either a large-scale freshwater anomaly is used to completely erase the previous convection pattern or a “surgical” anomaly is added to single grid points to turn off convection there. Under classical mixed-boundary conditions, different convection sites can lead to different overturning rates of deep water. The dynamics of the convection-driven flow is analyzed in some detail. With an energy balance atmosphere, in contrast, the overturning rate is very robust, apparently .
Atmospheric response to Ice Age conditions: Climatology near the Earth's surface

We present a 6-year simulation of the ice age atmosphere using the T21 Atmospheric General Circulation Model (AGCM) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The lower boundary conditions (18 kyr B.P.) were taken from CLIMAP Project Members (1981). The analysis is restricted to the surface climatology for two reasons: The surface fields are the test data derived from the geological record on land, and they define the upper boundary conditions for simulating the glacial ocean. Model results are shown for the mean annual surface fields of temperature, wind, and precipitation. In the global average the surface temperature was 4.7°C cooler compared to the present temperature. The wind strength increased in mid-latitudes and decreased in tropical trade wind regions. Precipitation did not change significantly in the global average; however, precipitation decreased over land and increased over the ocean. Most of the difference patterns between the present conditions and the ice age climate were statistically significant. The simulated surface climatology is roughly consistent with the paleogeological evidence and with numerical AGCM simulations of other authors. This suggests that presently available AGCMs, including the ECMWF model (T21), are able to describe climates far away from the present, although internal parameterizations were tuned to present data sets.
Spatial variability in correlation decay distance and influence on angular‐distance weighting interpolation of daily precipitation over Europe

Angular‐distance weighting (ADW) is a common approach for interpolation of an irregular network of meteorological observations to a regular grid. A widely used version of ADW employs the correlation decay distance (CDD) to (1) select stations that should contribute to each grid‐point estimate and (2) define the distance component of the station weights. We show, for Europe, that the CDD of daily precipitation varies spatially, as well as by season and synoptic state, and is also anisotropic. However, ADW interpolation using CDDs that varies spatially by season or synoptic state yield only small improvements in interpolation skill, relative to the use of a fixed CDD across the entire domain. If CDDs are optimized through cross validation, a larger improvement in interpolation skill is achieved. Improvements are larger for the determination of the state of precipitation (wet/dry) than for the magnitude. These or other attempts to improve interpolation skill appear to be fundamentally limited by the available station network. Copyright © 2008 Royal Meteorological Society
Spatially heterogeneous burial and high-P/T metamorphism in the Crescent Formation, Olympic Peninsula, Washington

Abstract The 16 km thick early to middle Eocene Crescent Formation exposed on the Olympic Peninsula represents one of the thickest stacks of basalt on Earth. It is variably metamorphosed at low grade, with evidence of both medium- and high-P/T conditions. Metasomatism is localized within a small number of layers, with variation relative to average values of as much as five standard deviations. The upper section tends to be lower grade but few systematic trends in mineralogy or mineral composition correlate with stratigraphic position. The boundary region between the lower and upper members contains the most dramatic metasomatic alteration as well as the best examples of barroisitic amphibole. Observations are consistent with a model in which extrusion of the basalt stack led to medium-P/T burial recrystallization in the zeolite and prehnite-pumpellyite facies, followed by localized, possibly fluid-facilitated lower-blueschist facies metamorphism; this high-P/T metamorphism may reflect the lowering of isotherms caused by subduction-zone refrigeration to the west of these rocks.
The affinities of a new theropod from the Alxa Desert, Inner Mongolia, People's Republic of China

Remains of bipedal saurischians from lacustrine strata of Albian age in the Alxa ("Alashan") Desert of Inner Mongolia represent a new taxon and the most complete remains of an Early Cretaceous theropod so far discovered in Asia. A skeletal reconstruction generally resembles that of a moderately large prosauropod with long arms and a short tail. However, in its detailed morphology the reptile appears to be close to the ancestry of the Therizinosauridae Maleev, 1954 (for which Segno-sauridae Perle, 1979 is probably a junior synonym). These theropods are best referred to the Tetanurae of Gauthier, 1986. However, a provisional analysis of the distribution of therizinosauroid characters within tetanurans suggests the existence of two subordinate groups: the Carnosauria (Allosaurus, dromaeosaurids, and tyrannosaurids) and the Oviraptorosauria (including therizinosauroids, ornithomimids, troodontids, and oviraptorids).
On the origin and timing of rapid changes in atmospheric methane during the Last Glacial Period

We present high resolution records of atmospheric methane from the GISP2 (Greenland Ice Sheet Project 2) ice core for four rapid climate transitions that occurred during the past 50 ka: the end of the Younger Dryas at 11.8 ka, the beginning of the Bølling‐Allerød period at 14.8 ka, the beginning of interstadial 8 at 38.2 ka, and the beginning of interstadial 12 at 45.5 ka. During these events, atmospheric methane concentrations increased by 200–300 ppb over time periods of 100–300 years, significantly more slowly than associated temperature and snow accumulation changes recorded in the ice core record. We suggest that the slower rise in methane concentration may reflect the timescale of terrestrial ecosystem response to rapid climate change. We find no evidence for rapid, massive methane emissions that might be associated with large‐scale decomposition of methane hydrates in sediments. With additional results from the Taylor Dome Ice Core (Antarctica) we also reconstruct changes in the interpolar methane gradient (an indicator of the geographical distribution of methane sources) associated with some of the rapid changes in atmospheric methane. The results indicate that the rise in methane at the beginning of the Bølling‐Allerød period and the later rise at the end of the Younger Dryas were driven by increases in both tropical and boreal methane sources. During the Younger Dryas (a 1.3 ka cold period during the last deglaciation) the relative contribution from boreal sources was reduced relative to the early and middle Holocene periods.
An adaptive method for service-level monitoring using autoregressive technique

SLA (Service Level Agreement) and its management have become more and more important for both service providers and customers, and the measurement of service level is fundamental for other management processes. The paper discusses the differences between service measurement and traditional network measurement from the perspective of sampling, and then deduces a theoretical lower-limit on sampling frequency. To reduce the number of samplings and keep high accuracy of service level data at the same time, the paper presents an adaptive algorithm based on estimation method. The random function is used to determine the actual sampling time in each sampling period, which is divided into a number of small even intervals. Then the auto-regressive model is chosen to estimate the current sampling value based on the previous sampling results. If the estimation result is within the range of probability accepted, sampling at this interval is given up. Thus, this algorithm reduces sampling's influence on the measured service by decreasing the sampling numbers. The experiments verify the effectiveness of this algorithm.
The Impacts of European and Asian Anthropogenic Sulfur Dioxide Emissions on Sahel Rainfall

AbstractIn this study, the atmospheric component of a state-of-the-art climate model [the Hadley Centre Global Environment Model, version 2–Earth System (HadGEM2-ES)] has been used to investigate the impacts of regional anthropogenic sulfur dioxide emissions on boreal summer Sahel rainfall. The study focuses on the transient response of the West African monsoon (WAM) to a sudden change in regional anthropogenic sulfur dioxide emissions, including land surface feedbacks but without sea surface temperature (SST) feedbacks. The response occurs in two distinct phases: 1) fast adjustment of the atmosphere on a time scale of days to weeks (up to 3 weeks) through aerosol–radiation and aerosol–cloud interactions with weak hydrological cycle changes and surface feedbacks and 2) adjustment of the atmosphere and land surface with significant local hydrological cycle changes and changes in atmospheric circulation (beyond 3 weeks). European emissions lead to an increase in shortwave (SW) scattering by increased sulfate.
Fuzzy patches on the Earth's core‐mantle boundary?

Recent seismological investigations reveal the presence of highly anomalous structures at the base of the mantle, modeled as patches ≤5–50 km thick having ultralow‐velocities (−δVP∼10–20%, −δVS∼10–50%). Waveform modeling shows seismological data are compatible with the patches exhibiting a wide range of density increases, up to δρ∼60%, which can be ascribed to chemical contamination of the deep mantle by the core. Not all anomalies require lowermost mantle partial melting, and may be located just below or right at the core‐mantle boundary (CMB): a ∼1–3 km thick zone of finite rigidity (crystallization? ) at the top of the outer core or, more generally, of gradational properties across the CMB can also explain observations. Fuzzy patches at the boundary may be zones of intense chemical and physical interactions between the mantle and core.
Extraction of solar and thermospheric information from the ionospheric electron density profile

This exploratory study of ionospheric electron density N-e profile assimilation concerns the extraction of information on exospheric temperature T-ex, atmospheric composition [O] and [N-2], meridional thermospheric winds, and solar EUV flux. These parameters are used as input variables to an ionospheric model and adjusted, one, two, or three at a time, to bring the model N-e profile into best agreement with an experimental N-e profile. The important ambiguity/uniqueness issue in the multiple-variable fit, which has yet to be addressed in the literature, is discussed. We found the following: (1) In a single-variable fit, any variable tested may be adjusted successfully to improve the data-model fit, but the validity of the derived variable generally depends on the validity of the values chosen for the fixed parameters. (2) The best fit model profile from a single-variable fit sometimes shows clear differences from the measured profile, indicating that multiple-variable fitting is warranted. The multiple-variable fit often greatly reduces the model-data profile differences and improves the error bars on the derived parameters. (3) Multiple-variable fits often show large variable correlations, indicating that variable determination is often not unique. (4) The meridional wind often shows weak correlation with other variables, suggesting that the meridional wind and any other parameter can be reliably extracted, provided that the other atmospheric variables are known. (5) [N-2] often shows strong correlation with other parameters (except with the wind). The EUV flux and [O] also show large correlation. (6) The T-ex-[O] and T-ex-EUV pairs show medium to high correlation. (7) The three-variable fits nearly always show large ambiguities in the derived parameters.
Coral reef habitat discrimination using multivariate spectral analysis and satellite remote sensing

Coral reefs are important both biologically and economically, but are under increasing pressure from pollution and human-induced disturbance. Coral reefs are often remote, relatively large and shallow. Thus, optical remote sensing techniques provide an efficient and cost-effective approach to mapping and monitoring the condition of reefs. We tested the hypothesis that in-situ spectral signatures, together with water column attenuation measurements, satellite imagery and Geographical Information System, can effectively differentiate reef substrates. In situ upwelling radiances were collected for coarse descriptive habitat types near Lee Stocking Island, Bahamas between 17 July and 27 July, 1998. Down-looking spectral scans from 300-750 nm were taken 1 m above the substrate and 1 m below the water surface, using a LiCor-1800 underwater spectroradiometer. Principal component analysis of upwelling radiances indicated that wavelengths from 515-580 nm are most useful in distinguishing between substrates. Landsat Thematic Mapper (TM) multi-spectral imagery was geo-registered and an ISODATA unsupervised classification was used to delineate reef features and associated communities. Using this method, we achieved an overall accuracy of 74% for coarse descriptive resolution mapping of seven substrate types (i.e. ocean, deep sand, shallow sand, deep coral, shallow coral, seagrass, and mixed sand and seagrass) within an area of 590 km 2 near Lee Stocking Island.
In The Process of Global Crisis the Importance ofTourism in Decreasing Regional DevelopmentDifferences: An Evaluation of Kastamonu Province inTurkey

The possibilities of transferring sources to decrease regional development differences by public authorities have been limited in the process of global crisis. Kastamonu Province, that was studied in our study, has occupied 47th place between 81 Provinces according to socio-economic development ranking in The State Planning Organization* 2011 data. Using tourism potential of Kastamonu Province, that has important tourism potential according to SWOT analysis done in this study, will accelerate socio-economic development of Province. In the process of Global crisis, evaluating tourism potentials successfully in less developed regions such as Kastamonu province will provide opportunity to remove regional development differences without using more public sources. Keywords: SWOT Analysis, Regional Development Differences, Tourism Economy, Socio-Economic Development, Global Crisis. * The State Planning Organization was reorganized as the Ministry of Development in June 2011.
The First Eocardiidae (Rodentia) in the Colhuehuapian (Early Miocene) of Bryn Gwyn (Northern Chubut, Argentina) and the Early Evolution of the Peculiar Cavioid Rodents

ABSTRACT Caviidae and Hydrochoeridae (extant Cavioidea s.s.), probably the most peculiar among rodents, are characterized by their evergrowing double-heart-shaped cheekteeth. They have classically been rooted in Eocardiidae, which ranges from Deseadan to ‘Colloncuran’ (late Oligocene-middle Miocene) in Patagonia, although in the Deseadan and Colhuehuapian (early Miocene) remains are very scanty. For the Colhuehuapian, only one species coming from the southern cliff of the Colhué Huapi Lake (Gran Barranca, Chubut, Argentina) was known so far. In this paper, the first Colhuehuapian eocardiids from outside Gran Barranca are reported: Luantus minor, sp. nov., and Chubutomys leucoreios, sp. nov. They are represented by two fragmentary mandibles and a few isolated cheek teeth, from the Trelew Member of the Sarmiento Formation at Bryn Gwyn, lower valley of the Chubut River, Chubut. The new species enlarge the knowledge of eocardiid diversity, and reinforce the hypothesis of a basal dichotomy for the group. L. minor represents one of the smallest species of the series Asteromys + Luantus + Phanomys + Eocardia, which likely gave rise to modern Cavioidea s.s. C. leucoreios pertains to a group of species with precocious hypsodonty and apparently low diversity, but without modern descendant.
European pollution outbreaks during ACE 2: Lofted aerosol plumes observed with Raman lidar at the Portuguese coast

During the Second Aerosol Characterization Experiment (ACE 2) in the summer of 1997, four pollution outbreaks from the European continent were monitored at Sagres (37°N, 9°W), Portugal, by applying the Raman lidar technique at a wavelength of 532 nm. The findings are presented in terms of vertical profiles of the volume extinction coefficient of the particles, the backscatter coefficient, the extinction-to-backscatter ratio (lidar ratio), the relative humidity, and the geometrical and optical depths of the marine boundary layer and the continental aerosol layers aloft. The lidar-derived optical depths are compared with results of simultaneously conducted star photometer observations. During all outbreaks, similar aerosol profiles were observed. Above the cold marine boundary layer the warm continental pollution plume extended from about 500 to a maximum height of 3500 m. Strong temperature inversions prohibited mixing of the two layers. The ACE 2 mean optical depths of the marine boundary layer and the aerosol layers aloft were about 0.05 and 0.1, respectively. Maximum values of the optical depth in the pollution plumes were close to 0.25 at 532 nm. On average, the free-tropospheric layers contributed about 60% to the total optical depth at the coast. Volume extinction coefficients were mainly between 30 and 70 Mm−1, and the lidar ratios ranged from 30 to 80 sr in the polluted continental air.
Long‐term carbon storage and hydrological control of CO2 exchange in tundra ponds in the Hudson Bay Lowland

Carbon dioxide fluxes and water balance were examined in 43 tundra ponds in the northern portion of the Hudson Bay Lowland near Churchill, Manitoba. Most of the ponds were hydrologically disconnected from their catchments during dry periods throughout the post‐melt season. However, episodic reconnection occurred following large precipitation events where depression storage was exceeded. Significant shifts in pond chemistry were observed following precipitation events, with the degree of CO2 saturation increasing during these periods. Pond CO2 concentrations rapidly fell to pre‐event levels following events, suggesting that hydrological connectivity can affect the magnitude and direction of CO2 gas fluxes in tundra ponds. Atmospheric CO2 invaded ponds with highly organic sediments for most of the summer, suggesting that terrestrially derived inorganic carbon was insufficient to meet the demands of algal net production. In contrast, ponds with highly mineral sediments continued to evade CO2 during the summer. In a subset of 11 ponds, long‐term rates of carbon accumulation in sediment ranged from 0·6 to 2·2 mol C m−2 year−1. Very strong correlations existed between average sediment accumulation rates and pond perimeters and basin areas suggesting that peat may be a major source of sediment carbon. Aeolian transport is also a potentially large source of sediment carbon. Copyright © 2004 John Wiley & Sons, Ltd.
Mapping marshland vegetation of San Francisco Bay, California, using hyperspectral data

Sustainable management of wetland ecosystems requires monitoring of vegetation dynamics, which can be achieved through remote sensing. This paper assesses the use of hyperspectral imagery to study the structure of wetlands of San Francisco Bay, California, USA. Spectral mixture analysis (SMA) and multiple endmember spectral mixture analysis (MESMA) were applied on an AVIRIS (Airborne Visible and Infrared Imaging Spectrometer) image to investigate their appropriateness to characterize marshes, with emphasis on the Spartina species complex. The role of rms. error as a measure of model adequacy and different methods for image endmember extraction were also evaluated. Results indicate that both SMA and MESMA are suitable for mapping the main components of the marsh, although MESMA seems more appropriate since it can incorporate more than one endmember per class. rms. error was shown not to be a measure of SMA model adequacy, but it can be used to help to assess model adequacy within groups of related models.
Modeling Modern Methane Emissions from Natural Wetlands. 1; Model Description and Results

Methane is an important greenhouse gas which contributes about 22% to the present greenhouse effect. Natural wetlands currently constitute the biggest methane source and were the major source in preindustrial times. Wetland emissions depend highly on the climate, i.e., on soil temperature and water table. To investigate the response of methane emissions from natural wetlands to climate variations, a process-based model that derives methane emissions from natural wetlands as a function of soil temperature, water table, and net primary productivity is used. For its application on the global scale, global data sets for all model parameters are generated. In addition, a simple hydrologic model is developed in order to simulate the position of the water table in wetlands. The hydrologic model is tested against data from different wetland sites, and the sensitivity of the hydrologic model to changes in precipitation is examined. The global methane- hydrology model constitutes a tool to study temporal and spatial variations in methane emissions from natural wetlands. The model is applied using high-frequency atmospheric forcing fields from ECMWF reanalyses of the period from 1982 to 1993. We calculate global annual methane emissions from wetlands to be 260 Tg yr -. Twenty-five percent of these methane emissions originate from wetlands north of 30oN. Only 60% of the produced methane is emitted, while the rest is reoxidized. A comparison of zonal integrals of simulated global wetland emissions and results obtained by an inverse modeling approach shows good agreement. In a test with data from two wetlands the seasonality of simulated and observed methane emissions agrees well.