bluuebunny/crossref_metadata_2025 huggingface dataset:
Geomorphic analysis of transient landscapes in the Sierra Madre de Chiapas and Maya Mountains (northern Central America): implications for the North American–Caribbean–Cocos plate boundary
Authors: Andreani L. , Gloaguen R.
Published: January 2016

Abstract. We use a geomorphic approach in order to unravel the recent evolution of the diffuse triple junction between the North American, Caribbean, and Cocos plates in northern Central America. We intend to characterize and understand the complex tectonic setting that produced an intricate pattern of landscapes using tectonic geomorphology, as well as available geological and geophysical data. We classify regions with specific relief characteristics and highlight uplifted relict landscapes in northern Central America. We also analyze the drainage network from the Sierra Madre de Chiapas and Maya Mountains in order to extract information about potential vertical displacements. Our results suggest that most of the landscapes of the Sierra Madre de Chiapas and Maya Mountains are in a transient stage. Topographic profiles and morphometric maps highlight elevated relict surfaces that are characterized by a low-amplitude relief. The river longitudinal profiles display upper reaches witnessing these relict landscapes. Lower reaches adjust to new base-level conditions and are characterized by multiple knickpoints. These results backed by published GPS and seismotectonic data allow us to refine and extend existing geodynamic models of the triple junction. Relict landscapes are delimited by faults and thus result from a tectonic control. The topography of the Sierra Madre de Chiapas evolved as the result of (1) the inland migration of deformation related to the coupling between the Chiapas Massif and the Cocos forearc sliver and (2) the compression along the northern tip of the Central American volcanic arc. Although most of the shortening between the Cocos forearc sliver and the North American Plate is accommodated within the Sierra de Chiapas and Sierra de los Cuchumatanes, a small part may be still transmitted to the Maya Mountains and the Belize margin through a "rigid" Petén Basin.
New remarkable Late Jurassic teleosts from southern Germany: Ascalaboidae n. fam., its content, morphology, and phylogenetic relationships
Authors: Arratia G.
Published: January 2016

Abstract. Complete morphological descriptions, as preservation permits, are provided for a new Late Jurassic fish taxon (Ebertichthys ettlingensis n. gen. et n. sp.) and a revision of some morphological features of Ascalabos voithii Graf zu Münster from the Solnhofen limestones, southern Germany. A new family, Ascalaboidae, is erected to include the two species. The new family is supported by numerous synapomorphies, e.g., maxilla with external row of small conical teeth increasing in size posteriorly, absence of gular plate, low number of vertebrae (34 to 39), deep and narrow supracleithrum – deeper than opercle, and vertebral centrum formation of caudal region including paired chordacentra (pseudo-diplospondyly) that fuse in early ontogeny forming one chordacentrum that is later surrounded by an autocentrum. A phylogenetic analysis based on 173 characters and 42 taxa was performed. Following the phylogenetic hypothesis, the sister-group relationship [Ascalabos + Ebertichthys] + more advanced teleosts stands above the node of Leptolepis coryphaenoides plus more advanced teleosts and below the node of Tharsis plus more advanced teleosts, and the new taxa are interpreted as extinct and primitive forms within Teleostei. The new genus and species is endemic and restricted to one Upper Jurassic locality – Ettling – whereas Ascalabos is known from different localities in the Solnhofen limestones, with the exception of Ettling.
Automatic segmentation and classification of seven-segment display digits on auroral images
Authors: Savolainen T. , Whiter D. K. , Partamies N.
Published: January 2016

Abstract. In this paper we describe a new and fully automatic method for segmenting and classifying digits in seven-segment displays. The method is applied to a data set consisting of about 7 million auroral all-sky images taken during the time period of 1973–1997 at camera stations centered around Sodankylä observatory in Northern Finland. In each image there is a clock display for the date and time together with the reflection of the whole night sky through a spherical mirror. The digitised film images of the night sky contain valuable scientific information, but are impractical to use without an automatic method for extracting the date-time from the display. We describe the implementation and the results of such a method in detail in this paper.
Forecasting auroras from regional and global magnetic field measurements
Authors: Kauristie K. , Myllys M. , Partamies N. , Viljanen A. , Peitso P. , Juusola L. , Ahmadzai S. , Singh V. , Keil R. , Martinez U. , Luginin A. , Glover A. , Navarro V. , Raita T.
Published: January 2016

Abstract. We present a concept for a Regional Auroral Forecast service (RAF), which uses near-real-time data from the IMAGE network of ground-based magnetometers operated in Northern Fennoscandia. Performance of RAF is demonstrated in a case study with auroral recordings from the Sodankylä research station. RAF is based on archived National Oceanic and Atmospheric Administration (NOAA) space weather alerts and regional magnetic field recordings (years 2002–2012). The archives are used to create a set of conditional probabilities, which tell the service user when the probability to see auroras exceeds the average conditions in Fennoscandia during the coming 0–12 hours. Favourable conditions for auroral displays are associated with ground magnetic field time derivative values (dB/dt) exceeding certain latitude dependent threshold values. Our statistical analyses reveal that the probabilities to record dB/dt exceeding the thresholds stay below 50% after NOAA alerts on X-ray bursts or on energetic particle flux enhancements. Therefore, those alerts are not very useful for auroral forecasts, if we want to keep the number of false alarms low. However, NOAA alerts on global geomagnetic storms (characterized with Kp values >4) enable probability estimates of >50% with lead times of 3–12 hours. RAF forecasts thus rely heavily on the well-known fact that bright auroras appear during geomagnetic storms. The additional new piece of information which RAF brings to the previous picture is the knowledge on typical storm durations at different latitudes. For example, the service users south of the Artic Circle will learn that after a NOAA ALTK06 issuance in night, auroral spotting should be done within 12 hours after the alert, while at higher latitudes conditions can remain favourable during the next night.
A 7-year dataset for driving and evaluating snow models at an arctic site (Sodankylä, Finland)
Authors: Essery R. , Kontu A. , Lemmetyinen J. , Dumon M. , Ménard C. B.
Published: January 2016

Abstract. Datasets derived from measurements at Sodankylä in the Finnish Arctic that can be used for driving and evaluating snow models are presented. The driving datasets comprise all of the meteorological variables required as inputs for physically-based snow models at hourly intervals: incoming solar and longwave radiation, snowfall and rainfall rates, air temperature, humidity, wind speed and atmospheric pressure. Two versions of the driving data are provided: one using radiation and wind speed measurements made above the height of the trees around the clearing where the evaluation data were measured and one with adjustments for the influence of the trees on conditions close to the ground. The available evaluation data include automatic and manual measurements of bulk snow depth and snow water equivalent, and profiles of snow temperature, snow density and soil temperature. A physically-based snow model is driven and evaluated with the datasets to illustrate their utility. Shading by trees extends the duration of snow cover on the ground by several days a year.
Seismic observations at the Sodankylä Geophysical Observatory: history, present and the futureitle of the manuscript
Authors: Kozlovskaya E. , Narkilahti J. , Nevalainen J. , Hurskainen R. , Silvennoinen H.
Published: January 2016

Abstract. Instrumental seismic observations in northern Finland started in 1950’s. They were originally initiated by the Institute of Seismology of the University of Helsinki (ISUH), but the staff of the Sodankylä Geophysical Observatory (SGO) and later, geophysicists of the University of Oulu (OU) were involved in development of seismological observations and research in northern Finland from the very beginning. This close cooperation between seismologists and technical staff of ISUH, OU and SGO continued later in a number of significant international projects and enabled a high level of seismological research in Finland. In our paper we present history and present state of seismic observations and seismological research in northern Finland at the OU and the SGO. This includes both seismic observations at permanent seismic stations and temporary seismic experiments by portable seismic equipment. We describe the present seismic instrumentation and major research topics of seismic group at the SGO and discuss the plans for future development of permanent seismological observations and portable seismic instrumentation at the SGO as a part of the EPOS-European Plate Observing System research infrastructure. We also present the research topics of recently organised Laboratory of Applied Seismology of the SGO, show examples of seismic observations performed by new seismic equipment of the Laboratory and selected results of time-lapse seismic body wave travel time tomography using the data of microseismic monitoring in the Pyhäsalmi Mine (northern Finland).
Brewer spectrometer total ozone column measurements in Sodankylä
Authors: Karppinen T. , Lakkala K. , Karhu J. M. , Heikkinen P. , Kivi R. , Kyrö E.
Published: January 2016

Abstract. Abstract. The Brewer total ozone column measurements started in Sodankylä in May 1988, 9 months after the agreement of The Montreal Protocol. The Brewer instrument has been well maintained and frequently calibrated since to produce a high quality ozone time series now spanning over 26 years. The data has now been uniformly reprocessed between 1988 and 2014. The quality of the data has been assured by automatic data rejection rules as well as by manual checking. The daily mean values calculated from highest quality direct sun measurements are available 77 % of time with up to 75 measurements per day on a clear day. Zenith sky measurements fill another 14 % of the time series and winter months are sparsely covered by moon measurements. The time series provides information to survey the evolution of Arctic ozone layer and can be used as a reference point for assessing other total ozone column measurement practises.
Data flow of spectral UV measurements at Sodankylä and Jokioinen
Authors: Mäkelä J. S. , Lakkala K. , Koskela T. , Karppinen T. , Karhu J. M. , Savastiouk V. , Suokanerva H. , Kaurola J. , Arola A. , Lindfors A. V. , Meinander O. , Leeuw G. , Heikkilä A.
Published: January 2016

Abstract. We describe the steps that are used at the Finnish Meteorological Institute (FMI) to process spectral ultraviolet (UV) radiation measurements made with its three Brewer spectrophotometers, located in Sodankylä (67° N) and Jokioinen (61° N). The spectrum is measured many times a day, following a pre-programmed schedule. Multiple corrections are made to the data in near real time (dark current, dead time, stray light, noise spikes, temperature, and cosine correction) and quality control is also performed automatically. The Brewers are integrated into the operational control systems at FMI, allowing both quick responses to malfunctions and quick dissemination of the data products. Several data products are produced, including the near-real-time UV index and various daily dosages. The daily doses are calculated each morning for the previous day's data. Once per year the responses of the Brewers are recalculated, and the corrected data are uploaded to the European UV database hosted by FMI.
Optical laboratory facilities at the Finnish Meteorological Institute – Arctic Research Centre
Authors: Lakkala K. , Suokanerva H. , Karhu J. M. , Aarva A. , Poikonen A. , Karppinen T. , Ahponen M. , Hannula H.-R. , Kontu A. , Kyrö E.
Published: January 2016

Abstract. This paper describes the laboratory facilities at the Finnish Meteorological Institute – Arctic Research Centre (FMI-ARC). They comprise an optical laboratory, a facility for biological studies and an office. A dark room has been built, in which an optical table and a fixed lamp test system are set up, and the electronics allow high precision adjustment of the current. The Brewer spectroradiometer, NILU-UV multifilter radiometer and ASD spectroradiometer of the FMI-ARC are regularly calibrated or checked for stability in the laboratory. The facilities are ideal for responding to the needs of international multidisciplinary research, giving the possibility to calibrate and characterize the research instruments as well as handle and store samples.
Distance Scaling Method for Accurate Prediction of Slowly Varying Magnetic Fields in Satellite Missions
Authors: Zacharias P. P. , Chatzineofytou E. G. , Spantideas S. T. , Capsalis C. N.
Published: January 2016

Abstract. In the present work, the determination of the magnetic behavior of localized magnetic sources from near field measurements is examined. The distance power law of the magnetic field fall-off is used in various cases to accurately predict the magnetic signature of an EUT consisting of multiple AC magnetic sources. Therefore, parameters concerning the location of the observation points (magnetometers) are stud ied towards this scope. The results clearly show that these parameters are independent of the EUT's size and layout. Additionally, the techniques developed in the present study enable the placing of the magnetometers close to the EUT, thus achieving high SNR. Finally, the proposed method is verified by real measurements, using a mobile phone as an EUT.
The abandoned surface mining sites in Czech Republic: Mapping and creating the database with GIS web application
Authors: Pokorný R. , Peterková M. T.
Published: January 2016

Abstract. Based on the vectorization of the 55-volume book series The quarry inventories of the Czechoslovak Republic/Czechoslovak Socialist Republic, published in the years 1932–1961, a new comprehensive database was built comprising 9958 surface mining sites of raw materials, which were active in the first half of the 20th century. The mapped area covers 40.9 % of the territory of the Czech Republic. For the purposes of visualization, a map application The Quarry Inventories Online was created that enables the data visualization.
Designing optimal greenhouse gas monitoring networks for Australia
Authors: Ziehn T. , Law R. M. , Rayner P. J. , Roff G.
Published: January 2016

Abstract. Atmospheric transport inversion is commonly used to infer greenhouse gas (GHG) flux estimates from concentration measurements. The optimal location of ground-based observing stations that supply these measurements can be determined by network design. Here, we use a Lagrangian particle dispersion model (LPDM) in reverse mode together with a Bayesian inverse modelling framework to derive optimal GHG observing networks for Australia. This extends the network design for carbon dioxide (CO2) performed by Ziehn et al. (2014) to also minimise the uncertainty on the flux estimates for methane (CH4) and nitrous oxide (N2O), both individually and in a combined network using multiple objectives. Optimal networks are generated by adding up to five new stations to the base network, which is defined as two existing stations, Cape Grim and Gunn Point, in southern and northern Australia respectively. The individual networks for CO2, CH4 and N2O and the combined observing network show large similarities because the flux uncertainties for each GHG are dominated by regions of biologically productive land. There is little penalty, in terms of flux uncertainty reduction, for the combined network compared to individually designed networks. The location of the stations in the combined network is sensitive to variations in the assumed data uncertainty across locations. A simple assessment of economic costs has been included in our network design approach, considering both establishment and maintenance costs. Our results suggest that, while site logistics change the optimal network, there is only a small impact on the flux uncertainty reductions achieved with increasing network size.
Improved Forecasting of Thermospheric Densities using Multi-Model Ensembles
Authors: Elvidge S. , Godinez H. C. , Angling M. J.
Published: January 2016

Abstract. This paper presents the ﬁrst known application of multi-model ensembles to the forecasting of the thermosphere. A multi-model ensemble (MME) is a method for combining different, independent, models. The main advantage of using an MME is to reduce the effect of model errors and bias, since it is expected that the model errors will, at least partly, cancel. The MME, with its reduced uncertain- ties, can then be used as the initial conditions in a physics-based thermosphere model for forecasting. This should increase the forecast skill since a reduction in the errors of the initial conditions of a model generally increases model skill. In this paper the Thermosphere-Ionosphere-Electrodynamic General Circulation Model (TIE-GCM), the US Naval Research Laboratory Mass Spectrometer and Incoherent Scatter radar Exosphere 2000 (NRLMSISE-00) and Global Ionosphere Thermosphere Model (GITM) have been used to construct the MME. TIE-GCM has been used for forecasting. It has been shown that thermospheric forecasts of up to 6 hours, that have been initialised using the MME, have a reduction in the root mean square error (compared to "standard" runs of the model) of greater than 60%. The paper also highlights differences in model performance between times of solar minimum and maximum.
Bottom RedOx Model (BROM, v.1.0): a coupled benthic-pelagic model for simulation of seasonal anoxia and its impact
Authors: Yakushev E. V. , Protsenko E. A. , Bruggeman J. , Bellerby R. G. J. , Pakhomova S. V. , Couture R.-M. , Yakubov S.
Published: January 2016

Abstract. Interaction between seawater and benthic sediments plays an important role in global biogeochemical cycling. Benthic fluxes of chemical elements (C, N, P, O, Si, Fe, Mn, S) directly affect redox state and acidification (i.e. pH and carbonate saturation), which in turn determine the functioning of the benthic and pelagic ecosystems. The redox state of the near bottom layer can change and oscillate in many regions responding to the supply of organic matter, physical regime and coastal discharge. The goal of this work was to develop a model that captures key biogeochemical processes occurring at the bottom boundary layer and sediment–water interface and analyze the changes that result from seasonal variability in redox conditions in the water column. We used a modular approach allowing the model to be coupled to existing hydrophysical models in 1-D, 2-D or 3-D. The model is capable to simulate seasonality in production and respiration of organic matter as well as in mixing, that leads to variation of redox conditions in the bottom boundary layer. Production and reduction of organic matter and varying redox conditions in the bottom boundary layer affect the carbonate system and lead to changes in pH and alkalinity. Bacteria play a significant role in the fate of organic matter due to chemosynthesis (autotrophs) and consumption of organic matter (heterotrophs). Changes in the bottom boundary layer redox conditions modify the distribution of nutrients (N and P) and redox metals (Mn and Fe). The model can be used for analyzing and interpreting data on sediment-water exchange, and estimating the consequences of forcing such as climate change, external nutrient loading, ocean acidification, carbon storage leakages, and point-source metal pollution.
Trans-pacific transport and evolution of aerosols: Evaluation of quasi global WRF-Chem simulation with multiple observations
Authors: Hu Zhiyuan , Zhao Chun , Huang Jianping , Leung L. Ruby , Qian Yun , Yu Hongbin , Huang Lei , Kalashnikova Olga V.
Published: January 2016

Abstract. A fully coupled meteorology-chemistry model (WRF-Chem) has been configured to conduct quasi-global simulation for the 5 years of 2010–2014 and evaluated with multiple observation datasets for first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational datasets for meteorological fields and aerosol properties. In general, precipitation and winds are well simulated by the model. The simulation captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflows of pollutants and dust and the emissions of marine aerosols. The assessment of simulated extinction Angstrom exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific that are dominated by marine aerosols near the surface and the outflow of pollutants and dust above 4 km are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western U.S., the model reproduces the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western U.S., while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show small interannual variability of aerosol characteristics for 2010–2014 averaged over three Pacific sub-regions. The evaluation in this study demonstrates that the WRF-Chem quasi global simulation can be used for investigating trans-Pacific transport of aerosols and providing reasonable inflow chemical boundaries for the western U.S. to further understand the impact of transported pollutants on the regional air quality and climate with high-resolution nested regional modeling.
On constraining the strength of the terrestrial CO2 fertilization effect in an Earth system model
Authors: Arora V. K. , Scinocca J. F.
Published: January 2016

Abstract. Earth system models (ESMs) explicitly simulate the interactions between the physical climate system components and biogeochemical cycles. Physical and biogeochemical aspects of ESMs are routinely compared against their observation-based counterparts to assess model performance and to evaluate how this performance is affected by ongoing model development. Here, we assess the performance of version 4.2 of the Canadian Earth system model against four, land carbon cycle focused, observation-based determinants of the global carbon cycle and the historical global carbon budget over the 1850–2005 period. Our objective is to constrain the strength of the terrestrial CO2 fertilization effect which is known to be the most uncertain of all carbon cycle feedbacks. The observation-based determinants include (1) globally-averaged atmospheric CO2 concentration, (2) cumulative atmosphere–land CO2 flux, (3) atmosphere–land CO2 flux for the decades of 1960s, 1970s, 1980s, 1990s and 2000s and (4) the amplitude of the globally-averaged annual CO2 cycle and its increase over the 1980 to 2005 period. The optimal simulation that satisfies constraints imposed by the first three determinants yields a net primary productivity (NPP) increase from ~ 58 Pg C yr−1 in 1850 to about ~ 74 Pg C yr−1 in 2005; an increase of ~ 27 % over the 1850–2005 period. The simulated loss in the global soil carbon amount due to anthropogenic land use change over the historical period is also broadly consistent with empirical estimates. Yet, it remains possible that these determinants of the global carbon cycle are insufficient to adequately constrain the historical carbon budget, and consequently the strength of terrestrial CO2 fertilization effect as it is represented in the model, given the large uncertainty associated with LUC emissions over the historical period.
YAC 1.2.0: An extendable coupling software for Earth system modelling
Authors: Hanke M. , Redler R. , Holfeld T. , Yastremsky M.
Published: January 2016

Abstract. A light-weight software framework has been developed as a library to realise the coupling of Earth system model components. The software provides a parallelised 2-dimensional neighbourhood search, interpolation, and communication for the coupling between any two model components. The software offers ﬂexible coupling of physical ﬁelds deﬁned on regular and irregular grids on the sphere without a priori assumptions about the particular grid structure or grid element types. All supported grids can be combined with any of the supported interpolations. We describe our approach and provide an overview about some of the algorithms we are using and the implemented functionality. The parallel performance is examined with a set of realistic use cases. The coupling software is now used for the coupling of the model components in the Icosahedral nonhydrostatic (ICON) general circulation model.
A 1/16° eddying simulation of the global NEMOv3.4 sea ice-ocean system
Authors: Iovino Doroteaciro , Masina Simona , Storto Andrea , Cipollone Andrea , Stepanov Vladimir N.
Published: January 2016

Abstract. Analysis of a global eddy-resolving simulation using the NEMO (version 3.4) general circulation model is presented. The model has 1/16° horizontal spacing at the equator, employs two displaced poles in the Northern Hemisphere, and uses 98 vertical levels. The simulation was spun up from rest and integrated for 11 model years, using ERA-Interim reanalysis as surface forcing. Primary intent of this hindcast is to test how the model represents upper ocean characteristics and sea ice properties. Numerical results show that, overall, the general circulation is well reproduced, with realistic values for overturning mass and heat transports. Analysis of the zonal averaged temperature and salinity, and the mixed layer depth indicate that the model average state is in good agreement with observed fields. Comparisons against observational estimates of mass transports through key straits indicate that most aspects of the model circulation are realistic. As expected, the simulation exhibits turbulent behaviour. The spatial distribution of the sea surface height variability from the model is close to the observed pattern. Despite the increase in resolution, the variability amplitude is still weak, in particular in the Southern Ocean. The distribution and volume of the sea ice are, to a large extent, comparable to observed values. Compared with a corresponding coarse-resolution configuration, the performance of the model is significantly improved, although relatively minor weaknesses still exist. We conclude that the model output is suitable for broader analysis to better understand upper ocean dynamics and ocean variability at global scales. This simulation represents a major step forward in the CMCC global ocean modelling, and constitutes the groundwork for future applications to short-range ocean forecasting.
Generalization and application of the flux-conservative thermodynamic equations in the AROME model of the ALADIN system
Authors: Degrauwe D. , Seity Y. , Bouyssel F. , Termonia P.
Published: January 2016

Abstract. General yet compact equations are presented to express the thermodynamic impact of physical parameterizations in a NWP or climate model. By expressing the equations in a ﬂux-conservative formulation, the conservation of mass and energy is a built-in feature of the system. Moreover, the centralization of all thermodynamic calculations guarantees a consistent thermodynamical treatment of the different processes. The generality of this physics-dynamics interface is illustrated by applying it in the AROME NWP model. The physics-dynamics interface of this model currently makes some approximations, which typically consist of neglecting some terms in the total energy budget, such as the transport of heat by falling precipitation, or the effect of diffusive moisture transport. Although these terms are usually quite small, omitting them from the energy budget breaks the constraint of energy conservation. The presented set of equations allows to get rid of these approximations, in order to arrive at a consistent and energy-conservative model. A verification in an operational setting shows that the impact on monthly-averaged, domain-wide meteorological scores is quite neutral. However, under specific circumstances, the supposedly small terms may turn out not to be entirely negligible. A detailed study of a case with heavy precipitation shows that the heat transport by precipitation contributes to the formation of a region of relatively cold air near the surface, the so-called cold pool. Given the importance of this cold pool mechanism in the life-cycle of convective events, it is advisable not to neglect phenomena that may enhance it.
Land surface parameter optimisation through data assimilation: the adJULES system
Authors: Raoult Nina M. , Jupp Tim E. , Cox Peter M. , Luke Catherine M.
Published: January 2016

Abstract. Land-surface models (LSMs) are crucial components of the Earth System Models (ESMs) which are used to make coupled climate-carbon cycle projections for the 21st century. The Joint UK Land Environment Simulator (JULES) is the land-surface model used in the climate and weather forecast models of the UK Met Office. In this study, JULES is automatically differentiated using commercial software from FastOpt, resulting in an analytical gradient, or adjoint, of the model. Using this adjoint, the adJULES parameter estimation system has been developed, to search for locally optimum parameter sets by calibrating against observations. This paper describes adJULES and demonstrates its ability to improve the model-data fit using eddy covariance measurements of gross primary production (GPP) and latent heat (LE) fluxes. adJULES also has the ability to calibrate over multiple sites simultaneously. This feature is used to define new optimised parameter values for the 5 Plant Functional Types (PFTS) in JULES. The optimised PFT-specific parameters improve the performance of JULES over 90 % of the sites used in the study, a third of which give similar reduction in errors as site specific optimisations. The new improved parameter set for JULES is presented along with the associated uncertainties for each parameter.
ICESHEET 1.0: A program to produce paleo-ice sheet models with minimal assumptions
Authors: Gowan E. J. , Tregoning P. , Purcell A. , Lea J. , Fransner O. J. , Noormets R. , Dowdeswell J. A.
Published: January 2016

Abstract. We describe a program that produces paleo-ice sheet models using an assumption of steady state, perfectly plastic ice flow behaviour. It incorporates three input parameters: ice margin, basal shear stress and basal topography. Though it is unlikely that paleo-ice sheets were ever in complete steady-state conditions, this method can produce an ice sheet without relying on complicated and unconstrained parameters such as climate and ice dynamics. This makes it advantageous to use in glacial-isostatic adjustment ice sheet models, which are often used as input parameters in global climate modelling simulations. We test this program by applying it to the modern Greenland Ice Sheet and Last Glacial Maximum Barents Sea ice sheet and demonstrate the optimal parameters that balance computational time and accuracy.
Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods
Authors: Petters M. D. , Kreidenweis S. M. , Ziemann P. J.
Published: January 2016

Abstract. A wealth of recent laboratory and field experiments demonstrate that organic aerosol composition evolves with time in the atmosphere, leading to changes in the influence of the organic fraction to cloud condensation nuclei (CCN) spectra. There is a need for tools that can realistically represent the evolution of CCN activity to better predict indirect effects of organic aerosol on clouds and climate. This work describes a model to predict the CCN activity of organic compounds from functional group composition. Following previous methods in the literature, we test the ability of semi-empirical group contribution methods in Köhler theory to predict the effective hygroscopicity parameter, kappa. However, in our approach we also account for liquid–liquid phase boundaries to simulate phase-limited activation behavior. Model evaluation against a selected database of published laboratory measurements demonstrates that kappa can be predicted within a factor of 2. Simulation of homologous series is used to identify the relative effectiveness of different functional groups in increasing the CCN activity of weakly functionalized organic compounds. Hydroxyl, carboxyl, aldehyde, hydroperoxide, carbonyl, and ether moieties promote CCN activity while methylene and nitrate moieties inhibit CCN activity. The model can be incorporated into scale-bridging test beds such as the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to evaluate the evolution of kappa for a complex mix of organic compounds and to develop suitable parameterizations of CCN evolution for larger-scale models.
A fully coupled atmosphere–ocean wave modeling system for the Mediterranean Sea: interactions and sensitivity to the resolved scales and mechanisms
Authors: Katsafados P. , Papadopoulos A. , Korres G. , Varlas G.
Published: January 2016

Abstract. It is commonly accepted that there is a need for a better understanding of the factors that contribute to air–sea interactions and their feedbacks. In this context it is important to develop advanced numerical prediction systems that treat the atmosphere and the ocean as a unified system. The realistic description and understanding of the exchange processes near the ocean surface requires knowledge of the sea state and its evolution. This can be achieved by considering the sea surface and the atmosphere as a continuously cross-talking dynamic system. Following and adapting concepts already developed and implemented in large-scale numerical weather models and in hurricane simulations, this study aims to present the effort towards developing a new, high-resolution, two-way fully coupled atmosphere–ocean wave model in order to support both operational and research activities. A specific issue that is emphasized is the determination and parameterization of the air–sea momentum fluxes in conditions of extremely high and time-varying winds. Software considerations, data exchange as well as computational and scientific performance of the coupled system, the so-called WEW (worketa-wam), are also discussed. In a case study of a high-impact weather and sea-state event, the wind–wave parameterization scheme reduces the resulted wind speed and the significant wave height as a response to the increased aerodynamic drag over rough sea surfaces. Overall, WEW offers a more realistic representation of the momentum exchanges in the ocean wind–wave system and includes the effects of the resolved wave spectrum on the drag coefficient and its feedback on the momentum flux.
PRACTISE – Photo Rectification And ClassificaTIon SoftwarE (V.2.1)
Authors: Härer S. , Bernhardt M. , Schulz K.
Published: January 2016

Abstract. Terrestrial photography combined with the recently presented Photo Rectification And ClassificaTIon SoftwarE (PRACTISE V.1.0) has proven to be a valuable source to derive snow cover maps in a high temporal and spatial resolution. The areal coverage of the used digital photographs is however strongly limited. Satellite images on the other hand can cover larger areas but do show uncertainties with respect to the accurate detection of the snow covered area. This is especially the fact if user defined thresholds are needed, e.g. in case of the frequently used normalized-difference snow index (NDSI). The definition of this value is often not adequately defined by either a general value from literature or over the impression of the user, but not by reproducible independent information. PRACTISE V.2.1 addresses this important aspect and shows additional improvements. The Matlab-based software is now able to automatically process and detect snow cover in satellite images. A simultaneously captured camera-derived snow cover map is in this case utilized as in situ information for calibrating the NDSI threshold value. Moreover, an additional automatic snow cover classification, specifically developed to classify shadow-affected photographs, was included. The improved software was tested for photographs and Landsat 7 Enhanced Thematic Mapper (ETM+) as well as Landsat 8 Operational Land Imager (OLI) scenes in the Zugspitze massif (Germany). The results show that using terrestrial photography in combination with satellite imagery can lead to an objective, reproducible, and user-independent derivation of the NDSI threshold and the resulting snow cover map. The presented method is not limited to the sensor system or the threshold used in here but offers manifold application options for other scientific branches.
The assessment of a global marine ecosystem model on the basis of emergent properties and ecosystem function: a case study with ERSEM
Authors: de Mora L. , Butenschön M. , Allen J. I.
Published: January 2016

Abstract. Ecosystem models are often assessed using quantitative metrics of absolute ecosystem state, but these model–data comparisons are disproportionately vulnerable to discrepancies in the location of important circulation features. An alternative method is to demonstrate the models capacity to represent ecosystem function; the emergence of a coherent natural relationship in a simulation indicates that the model may have an appropriate representation of the ecosystem functions that lead to the emergent relationship. Furthermore, as emergent properties are large-scale properties of the system, model validation with emergent properties is possible even when there is very little or no appropriate data for the region under study, or when the hydrodynamic component of the model differs significantly from that observed in nature at the same location and time.A selection of published meta-analyses are used to establish the validity of a complex marine ecosystem model and to demonstrate the power of validation with emergent properties. These relationships include the phytoplankton community structure, the ratio of carbon to chlorophyll in phytoplankton and particulate organic matter, the ratio of particulate organic carbon to particulate organic nitrogen and the stoichiometric balance of the ecosystem.These metrics can also inform aspects of the marine ecosystem model not available from traditional quantitative and qualitative methods. For instance, these emergent properties can be used to validate the design decisions of the model, such as the range of phytoplankton functional types and their behaviour, the stoichiometric flexibility with regards to each nutrient, and the choice of fixed or variable carbon to nitrogen ratios.
Towards convection-resolving, global atmospheric simulations with the Model for Prediction Across Scales (MPAS) v3.1: an extreme scaling experiment
Authors: Heinzeller D. , Duda M. G. , Kunstmann H.
Published: January 2016

Abstract. The Model for Prediction Across Scales (MPAS) is a novel set of Earth system simulation components and consists of an atmospheric model, an ocean model and a land-ice model. Its distinct features are the use of unstructured Voronoi meshes and C-grid discretisation to address shortcomings of global models on regular grids and the use of limited area models nested in a forcing data set, with respect to parallel scalability, numerical accuracy and physical consistency. This concept allows one to include the feedback of regional land use information on weather and climate at local and global scales in a consistent way, which is impossible to achieve with traditional limited area modelling approaches. Here, we present an in-depth evaluation of MPAS with regards to technical aspects of performing model runs and scalability for three medium-size meshes on four different high-performance computing (HPC) sites with different architectures and compilers. We uncover model limitations and identify new aspects for the model optimisation that are introduced by the use of unstructured Voronoi meshes. We further demonstrate the model performance of MPAS in terms of its capability to reproduce the dynamics of the West African monsoon (WAM) and its associated precipitation in a pilot study. Constrained by available computational resources, we compare 11-month runs for two meshes with observations and a reference simulation from the Weather Research and Forecasting (WRF) model. We show that MPAS can reproduce the atmospheric dynamics on global and local scales in this experiment, but identify a precipitation excess for the West African region. Finally, we conduct extreme scaling tests on a global 3 km mesh with more than 65 million horizontal grid cells on up to half a million cores. We discuss necessary modifications of the model code to improve its parallel performance in general and specific to the HPC environment. We confirm good scaling (70 % parallel efficiency or better) of the MPAS model and provide numbers on the computational requirements for experiments with the 3 km mesh. In doing so, we show that global, convection-resolving atmospheric simulations with MPAS are within reach of current and next generations of high-end computing facilities.
Geothermal heat pump system assisted by geothermal hot spring
Authors: Nakagawa M. , Koizumi Y.
Published: January 2016

Abstract. The authors propose a hybrid geothermal heat pump system that could cool buildings in summer and melt snow on the pedestrian sidewalks in winter, utilizing cold mine water and hot spring water. In the proposed system, mine water would be used as cold thermal energy storage, and the heat from the hot spring after its commercial use would be used to melt snow for a certain section of sidewalks. Neither of these sources is viable for direct use application of geothermal resources, however, they become contributing energy factors without producing any greenhouse gases. To assess the feasibility of the proposed system, a series of temperature measurements in the Edgar Mine (Colorado School of Mines' experimental mine) in Idaho Springs, Colorado, were first conducted, and heat/mass transfer analyses of geothermal hot spring water was carried out. The result of the temperature measurements proved that the temperature of Edgar Mine would be low enough to store cold groundwater for use in summer. The heat loss of the hot spring water during its transportation was also calculated, and the heat requirement for snow melt was compared with the heat available from the hot spring water. It was concluded that the heat supply in the proposed usage of hot spring water was insufficient to melt the snow for the entire area that was initially proposed. This feasibility study should serve as an example of "local consumption of locally available energy". If communities start harnessing economically viable local energy in a responsible manner, there will be a foundation upon which to build a sustainable community.
Soil–aquifer phenomena affecting groundwater under vertisols: a review
Authors: Kurtzman D. , Baram S. , Dahan O.
Published: January 2016

Abstract. Vertisols are cracking clayey soils that (i) usually form in alluvial lowlands where, normally, groundwater pools into aquifers; (ii) have different types of voids (due to cracking), which make flow and transport of water, solutes and gas complex; and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil–aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants: in this section lysimeter-to basin-scale observations that show the significance of cracks as preferential-flow paths in vertisols, which bypass matrix blocks in the unsaturated zone, are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed; (2) soil cracks as deep evaporators and unsaturated-zone salinity: deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed; (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization: the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; (4) relatively little nitrate contamination in aquifers under vertisols: in this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related groundwater problem). Denitrification is probably the main mechanism supporting this resistance, whereas a certain degree of anion-exchange capacity may have a retarding effect as well.