bluuebunny/crossref_metadata_2025 huggingface dataset:
Distributed LES-based drag parameterisation for heterogeneous urban neighbourhoods
Authors: Sützl Birgit , van Reeuwijk Maarten , Rooney Gabriel
Published: March 2020

The form and density of buildings modify the air flow and momentum exchange within cities, and therefore strongly affect local wind, temperature, humidity and pollution. Numerical weather prediction (NWP) models currently do not account for heterogeneity in their surface layer parameterisation. Regional models represent buildings, if at all, based on quantities such as plan and frontal area indices, and parameterise their impact at the lowest grid level, even though buildings can protrude a significant height into the atmospheric boundary layer.

To investigate how to parameterise urban roughness in NWP, we analysed high-resolution building-resolving large eddy simulations (LES) with the uDALES model over a range of heterogeneous urban neighbourhoods. The simulation setups have a similar building density and frontal aspect ratio, but vary in complexity with different building heights, plan areas and street geometries. Using the LES data we developed a parameterisation model that describes the vertical distribution of building drag inside a heterogeneous urban canopy. The drag force exerted on the atmosphere represents the momentum loss in the urban canopy due to buildings and can be incorporated as additional stress term in the momentum equations. The parameterisation represents the spatial heterogeneity effects in a one-dimensional vertical function, and links the building drag force to the heterogeneity of building layouts. A characterisation of the vertical and horizontal heterogeneity of built-up neighbourhoods is used as model input.
Post-processing for NWP Outputs Based on Machine Learning for 2022 Winter Olympics Games over Complex Terrain
Authors: Yanyan Kang , Haochen Li , Jiangjiang Xia , Yingxin Zhang
Published: March 2020

    Weather forecasts play an important role in the Olympic game,especially the mountain snow projects, which will help to find a "window period" for the game. The winter Olympics track is located on very complex terrain, and a detailed weather forecast is needed. A Post-processing method based on machine learning is used for the future-10-days weather prediction with 1-km spatial resolution and 1-hour temporal resolution, which can greatly improve accuracy and refinement of numerical weather prediction(NWP). The ECWMF/RMAPS model data and the automatic weather station data(AWS) from 2015-2018 are prepared for the training data and test data, included 48 features and 4 labels (the observed 2m temperature, relative humidity , 10m wind speed and wind direction ). The model data are grid point, while the AWS data are station point. We take the nearest 9 model point to predict the station point, instead of making an interpolation between the grid point and station point. Then the feature number will be 48*9 in dataset. The interpolation error from grid point to station is eliminated,and the spatial distribution is considered to some extent. Machine leaning method we used are SVM, Random Forest, Gradient Boosting Decision Tree(GBDT) and XGBoost. We find that XGBoost method performs best, slightly better than GBDT and Random Forest. It is noted that we did some feature engineering work before training, and we found that it’s not that the more features, the better the model, while 10 features are enough. Also there is an interesting thing that the features that closely related the labels values becomes less important as the forecast time increases,such as the model outputed 2m temperature, 10m wind speed and wind direction. While some features that forecasters don’t pay attention to become more important in the 6-10 days prediction, such as latent heat flux, snow depth and so on. So it’s necessary to train the model based on dynamic weight parameters for different forecast time. Through the post-processing based on the machine learning method, the forecast accuracy has been greatly improved compared with EC model. The averaged forecast accuracy of 0-10 days for 2m relative humidity, 10m wind speed and direction has been increased by almost 15%, and the temperature accuracy has been increased by 20%~40% ( 40% for 0-3 days, and the accuracy decreased with the forecast time ). 
Rapid and intense CO2 emissions into the atmosphere: Examples from the end-Triassic extinction
Authors: Capriolo Manfredo , Mills Benjamin , Newton Robert , Dal Corso Jacopo , Dunhill Alexander , Marzoli Andrea
Published: March 2020

The coincidence between mass extinction events and the emplacement of Large Igneous Provinces (LIPs) in the Phanerozoic geological record points to the magmatic CO2 degassing as the potential trigger of rapid global-scale climatic and environmental changes. The Central Atlantic Magmatic Province (CAMP) is one of the Earth’s hugest LIPs, and is coincident with the end-Triassic extinction, at ca. 201.5 Ma. Such LIPs emplacement and associated magmatic CO2 degassing have traditionally been interpreted as occurring over periods much longer than those of anthropogenic CO2 emissions, however our improving understanding of LIPs activity is reducing these timescales, with the latest estimates indicating CAMP magmatic pulses lasting approximately a few centuries each and characterized by high eruption rates [1; 2]. We employed a biogeochemical model to investigate the effects on ocean-atmosphere system and climate of these CAMP magmatic pulses, and to test whether such rapid and intense magmatic CO2 degassing is consistent with the climatic, geochemical and palaeontological record of the end-Triassic. Hence, we compared the modern anthropogenic emissions (since the Industrial Revolution) with the pulsed magmatic degassing during CAMP emplacement, in order to evaluate the impact of rapid and intense events on climate and environment changes.

 

[1] Knight et al. (2004), Earth Planet. Sci. Lett. 228, 143-160. [2] Marzoli et al. (2019), J. Petrol. 60, 945-996.
Evaluation of extreme precipitation over the Nordic region using a convection-permitting regional climate model
Authors: Toivonen Erika , Belušić Danijel , Thomassen Emma  Dybro , Berg Peter , Christensen Ole Bøssing , Dobler Andreas , Dyrrdal Anita Verpe , Haugen Jan Erik , Jylhä Kirsti , Kjellström Erik , Landgren Oskar , Lind Petter , Lindstedt David , Matte Dominic , Mäkelä Antti , Olsson Jonas , Pedersen Rasmus Anker , Wang Fuxing , Yang Wei
Published: March 2020

Extreme precipitation events have a major impact upon our society. Although many studies have indicated that it is likely that the frequency of such events will increase in a warmer climate, little has been done to assess changes in extreme precipitation at a sub-daily scale. Recently, there is more and more evidence that high-resolution convection-permitting models (CPMs) (grid-mesh typically < 4 km) can represent especially short-duration precipitation extremes more accurately when compared with coarser-resolution regional climate models (RCMs).

This study investigates sub-daily and daily precipitation characteristics based on hourly output data from the HARMONIE-Climate model at 3-km and 12-km grid-mesh resolution over the Nordic region between 1998 and 2018. The RCM modelling chain uses the ERA-Interim reanalysis to drive a 12-km grid-mesh simulation which is further downscaled to 3-km grid-mesh resolution using a non-hydrostatic model set-up.

The statistical properties of the modeled extreme precipitation are compared to several sub-daily and daily observational products, including gridded and in-situ gauge data, from April to September. We investigate the skill of the model to represent different aspects of the frequency and intensity of extreme precipitation as well as intensity–duration–frequency (IDF) curves that are commonly used to investigate short duration extremes from an urban planning perspective. The high grid resolution combined with the 20-year-long simulation period allows for a robust assessment at a climatological time scale and enables us to examine the added value of high-resolution CPM in reproducing precipitation extremes over the Nordic region. Based on the tentative results, the high-resolution CPM can realistically capture the characteristics of precipitation extremes, for instance, in terms of improved diurnal cycle and maximum intensities of sub-daily precipitation.
Magma-rich transform margins: example from the Limpopo transform fault zone between Mozambique and Antarctica
Authors: Leroy Sylvie , Roche Vincent , Guillocheau François , Dietrich Pierre , Revillon Sidonie , Watremez Louise , Robin Cécile , Despinois Frank , Vetel William
Published: March 2020

Transform continental margins known across the Earth represent 31% of passive margins. Resulting from first-order plate tectonic processes, transform margins record a diachronous evolution mainly defined by three successive stages, including intra-continental transform faulting, active and passive transform margin. Due to their high complexity and a lack of large hydrocarbon discoveries (i.e. not a target for oil industry), they have only been sparsely studied, especially when compared with other margin types (i.e. divergent or convergent).

                  We present the structure and evolution of the NS-trending Limpopo Transform Fault Zone (LTFZ), corresponding to the main fracture zone from western part of the Africa-Antarctica Corridor (AAC). Here, we combine published and unpublished dataset (seismic reflection profiles, wells, multibeam bathymetry, gravity, magnetic data) in order to propose an interpretation of the LTFZ structure and adjoining segments and their evolution through time, from rifting to spreading.

The LTFZ is composed of two main segments: the East Limpopo segment and the Astrid conjugate one and the North and South Natal segment including the Dana-Galathea Plateau (Mozambique side) and the Maud rise/east of Grunehogna craton (Antarctica margin). The LTFZ offsets the segments of divergent conjugate margins (Southern Natal-off Grunehogna craton in the west and Beira High Angoche-Riiser Larsen Sea in the east) since 155 Ma (chron M25). We focus on the evolution of the transform fault zone from its initiation at chron M25 up to chron M0 (~126 Ma, Barremian). Oceanic spreading onset at chron M25 in the south of Beira High segment and Dana-Galathea Plateau triggered the uplift and erosion of the proximal parts of the margin and the formation of several seaward dipping reflectors wedges. Plate kinematic implies an NNW-SSE opening of the LTFZ. The oblique component of opening promotes the setting up of several volcanic wedges. These wedges rejuvenate southward trough time, which is consistent with the sliding of Antarctica with respect to Africa and thus confirm the diachronous evolution of the transform fault zone.
The contradictory role of fire from the nature conservation perspective
Authors: Valkó Orsolya
Published: March 2020

Fire is a globally relevant natural or anthropogenic phenomenon with a rapidly increasing importance in the era of the climate change. In each year, approximately 4% of the global land surface burns. For effective ecosystem conservation, we need to understand fire regimes, identify potential threats, and also the possibilities in the application of prescribed burning for maintaining ecosystems.

Here I provide an overview on the contradictory role of fire in nature conservation from two continents with contrasting fire histories, focusing on European and North-American grasslands. I show that the ecological effects of fire depend on the fire regime, fire history, ecosystem properties and the socio-economic environment. Catastrophic wildfires, arson, too frequent or improperly planned human-induced fire often lead to the degradation of the ecosystems, the disappearance of rare plant and animal species, and to the encroachment of weed and invasive species. I illustrate with examples that these negative fire effects act synergistically with the human-induced changes in land use systems.

I also underline with case studies that in both regions, properly designed and controlled prescribed burning regimes can aid the understanding and managing disturbance-dependent ecosystems. Conservation in these dynamic and complex ecosystems is far more than fencing and hoping to exclude disturbance; but the contrary: disturbance is needed for ecosystem functioning. Therefore, the conservation of dynamic, diverse and functioning ecosystems often require drastic interventions and an unconventional conservation attitude. However, the expanding urban-wildlife interface makes the application of prescribed burning challenging worldwide. A major message for the future is about fire policy: it is crucial to moderate the negative effects of fire, however, properly designed prescribed burning should be used as a tool for managing and conserving disturbance-dependent ecosystems.
Geomorphology, distribution and composition of subglacial triangular hummocks (murtoos) in Sweden and Finland
Authors: Johnson Mark , Mäkinen Joni , Peterson Gustaf , Ojala Antti , Öhrling Christian , Ahokangas Elina , Remmert Izabella , Kajuutti Karu , Palmu Jukka-Pekka
Published: March 2020

Triangular hummocks of subglacial origin have been identified in Sweden and Finland due to the increased resolution provided by LiDAR imagery. Their triangular shape is distinctive and recognizable as clearly identifiable landforms. These forms have been previously mapped in some cases as dead-ice hummocks, but geomorphic relationships with eskers, flutes ribbed moraine and De Geer moraines show these to be subglacial. We refer to these new landforms as ‘murtoos.’ Morphometric measurements show murtoos to be 50 to 200 m long and 50 to 100 m wide. The orientation of their apices strongly correlates with local ice-flow orientation. They form preferentially on beds that slope down-ice.  In many cases, they occur in patches in an ice-flow parallel path with eskers, defining corridors we believe to be of subglacial meltwater origin. Murtoos are composed primarily of heterogeneous diamicton with variable amounts of bedded sand and gravel. Murtoos are most common where glacier-melt rates were high during deglaciation (Bølling-Allerød and Holocene), and they are absent where extensive frozen-bed conditions were present. We suggest murtoos are a landform produced as a glacier-bed adjustment to increased delivery of supraglacial meltwater during deglaciation.
Co-movements of financial volatilities in a changing environment
Authors: Martins Susana
Published: March 2020

Anthropogenic climate change has been attributed mainly to the excessive burning of fossil fuels and the release of carbon compounds. On average, 75% of the primary energy is still being produced by means of fossil fuels. In order to mitigate the global effects of climate change, a transition towards low-carbon economies is thus necessary. However, given current technology, this transition requires investments to shift away from high-carbon assets and so the effectiveness of changes in investment decisions depends highly on the expectations about policy change (e.g. regarding carbon pricing). The systemic implications of disruptive technological progress on the prices of carbon-intensive assets are thus compounded by the geopolitical nature of transition risk. If investors are pricing transition risk, this implies prices of high-carbon assets should all be responsive to climate-related policy news. For modelling the dynamics of volatility co-movements at the global scale, we propose an extension to the global volatility factor model of Engle and Martins (\textit{in preparation}). To allow for richer structures of the global volatility process, including dynamics, structural changes, outliers or time-varying parameters, we adapt the indicator saturation approach introduced by Hendry (1999) to the second moment and high-frequency data. In the model, climate change is interpreted as a source of structural change affecting the financial system. The new global volatility model is applied to the daily share prices of major Oil and Gas companies from different countries traded in the NYSE to avoid asynchronicity. As a proxy for climate change risk, we use the climate change news index of Engle et al. (2019). This index is a time series that captures news about long-run climate risk. In particular, we use the innovations in their negative (or bad) news index which is based on sentiment analysis.
Solution to an enigma: Explaining the slope of carbon vs. oxygen isotopic disequilibrium in biogenic and inorganic carbonates
Authors: Zeebe Richard , Yumol Lauren , Uchikawa Joji
Published: March 2020

A widespread phenomenon in biogenic and inorganic carbonates that are formed out of isotopic equilibrium is a nearly ubiquitous co-variation (slope) of carbon vs. oxygen isotopes, in e.g., speleothem and cryogenic carbonates, shells and skeletons of foraminifera, corals etc. For proxy calibrations, it is critical to understand such isotope variations (often labeled kinetic or vital effects) in proxies widely used for paleo-reconstructions. Given that this phenomenon is observed in inorganic carbonates and biogenic carbonates across different phyla suggest a common underlying mechanism, possibly independent of biological controls, that is, likely of inorganic origin. Here we present results from laboratory experiments on synthetic carbonate precipitation to constrain the kinetic isotope fractionation factor (KFF) of carbon and oxygen during CO2 hydration. We used an experimental setup similar to that of an earlier study but with important modifications and tight temperature and pH control. The average d13C and d18O values of our carbonate samples (BaCO3) produced at 25 deg C and pH = 8.0 (NBS) are -29.7 +- 0.71 per mil (VPDB) and 18.8 +- 0.56 per mil (VSMOW), respectively. From the isotope data, we calculate our experimental 13KFF and 18KFF, which refer to the 13C/12C and 18O/16O fractionation between CO2(g) and BaCO3, where the d13C and d18O values of CO2(g) were calculated using known equilibrium fractionation factors. Our results show that our KFFs are the largest values compared to previously reported experimental KFFs (except for one study), suggesting that our values are closest to the full isotopic disequilibrium during CO2 hydration. Based on our KFFs, we will present the expected slope of carbon vs. oxygen isotopic disequilibrium from kinetic effects during CO2 hydration. We will also discuss the expected slope from equilibrium effects of solution pH on oxygen isotopes. Comparison with field and culture data will reveal the origin of the slope of carbon vs. oxygen isotopic disequilibrium in biogenic and inorganic carbonates.
Sensitivity analysis to physical parameterizations schemes applied for wind forecasting
Authors: Merino Andrés , Mérida Guillermo , Melcón Pablo , López Laura , Marcos José Luis , Romo Carmen Victoria , Seoane Neves , Navarro Andrés , García-Ortega Eduardo , Sánchez Gómez José Luis
Published: March 2020

The airborne research center called CIAR is placed in the airfield of Rozas (Lugo, Spain). It is a center for experimentation and development of new Unmanned Aerial Vehicles. Since you need to have a good planning of the flights of the prototypes, it is necessary to have a good prediction of the wind at different levels of height.

To obtain a reliable database for wind at different vertical levels, three types of instruments have been used: anemometers installed at 10 meters high to determine surface wind, a sodar for levels below 150 meters and a wind radar for those between 200 and 3000 m high above the CIAR level.

Concerning the mesoscale modelling: we have used the WRF with 48 sigma levels and horizontal resolution of up to 3 x 3 km. Therefore, we have applied multiphysics ensemble techniques. Five combinations of microphysics schemes (AEROSOL THOMPSON, MORRISON 2 MOMENTS, THOMPSON, GODDARD and WRF 2 MOMENTS), three of PBL (MYNN3, YSU and MYJ), and two of Surface (NOAA and RUC) have been selected.

Once the wind data databases were obtained, by means of the different instrumentation indicated above, it has been compared with each of the 20 WRF scenarios. To visualize the results, Taylor diagrams have been used for the different heights.

In summary, some conclusions have been found:

It’s necessary distinguish between low levels and those of slightly higher heights. On the surface, the scenarios with the PBL parameterizations called YSU and MYNN3 show better results.

It seems that the microphysics schemes settings have a less importance in wind forecast, which is consistent with the physical interpretation.

Above 200 meter, the 20 scenarios behave more satisfactorily with excellent correlation coefficients and low standard deviations

Acknowledgment

Data support came from the Atmospheric Physics Group, IMA, University of León, Spain, and the National Institute of Aerospace Technology (INTA). This research was carried out in the framework of the SAFEFLIGHT project, financed by MINECO (CGL2016‐78702) and LE240P18 project (Junta de Castilla y León). We also thank R. Weigand for computer support to the research group.
Assessment of groundwater and surface water quality for irrigation suitability in Rupnagar District, Punjab, India
Authors: Kaur Navjot , Paikaray Susanta
Published: March 2020

Groundwater and Sutlej river water are major sources of irrigation in Rupnagar district of Punjab. Water quality was examined for their agricultural suitability using a total of 54 surface water (16 from Sutlej and 6 from Sirsa River) and groundwater (total 32 of ~160 m depth) samples from Pre- (June 2019) and post-monsoon (Dec 2018) seasons. On-site parameters (electrical conductivity, pH, total dissolved solids) indicate permissible pH (pH 6.6-8.2) and conductivity (147-1953 μS/cm), while 18.5% of samples are brackish salt to salt category type on salinity index. The results of these parameters were further interpreted and measured with different irrigation indexes like sodium percent (SP), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), chloride concentrations and Wilcox diagram. Similarly, most of the samples (except Sutlej river water samples) were found to be above permissible limits with respect to SP (5.36-81.01) and RSC (0-6.23), but SAR is indicative of suitability for irrigation purposes (0.11-8.3). The suitability for irrigation as per SAR is because of low sodium content in all the samples relative to calcium and magnesium. The Wilcox diagram of pre-monsoon samples indicate high, medium and low saline to low sodium hazard except 1 sample with high saline to medium sodium hazard and salinity-sodium hazard in post-monsoon is comparatively lower than that of pre-monsoon. However careful observation of the complete data analysis suggests that all the parameters in Sutlej river water samples were found to be suitable for irrigation while most of the groundwater samples and 3 samples from Sirsa river were unfit for irrigation purposes as inferred from SP, RSC and Wilcox diagram.
Decadal physical-biogeochemical changes in the Newfoundland and Labrador ecosystem
Authors: Cyr Frédéric , Gibb Olivia , Bélanger David , Han Guoqi , Maillet Gary , Pepin Pierre
Published: March 2020

Located on a crossroads of some of the main currents associated to the Atlantic meridional overturning circulation (AMOC), Newfoundland and Labrador (NL) shelves are specially affected by changes in large-scale ocean circulation. Such circulation changes impact not only the regional climate, but also the overall water masses composition, with consequences on physical conditions, nutrient availability, oxygen content, pH, etc. Systematic hydrographic observations of this system have been carried out by Canada and other countries since 1948. The observational program was reinforced in 1999 with the creation of the Atlantic Zone Monitoring Program (AZMP), ensuring enhanced seasonal coverage and new biogeochemical observations. In 2014, this monitoring was augmented with the monitoring of ocean acidification parameters. Here we review historical physical-biogeochemical changes on the NL shelves, with an emphasis on low frequency variability and cycles. Results suggest, for example, that the cold intermediate layer (CIL), a cold mid-depth layer that is a key feature of the NL ecosystem, exhibited profound changes during the last 70 years. In the mid 60's, the CIL was anomalously warm compared to the rest of the time series. This warm period was followed by a cold period centered in the early 90's. Historical salinity records also suggest that fresher waters are found during warmer years, and vice-versa. Nitrate/Phosphate ratios suggest recent changes in water masses composition towards less Arctic waters flowing on the shelves. This is concurrent with a reduction in nutrients concentration on the NL shelves since about 2012, together with changes in the strength of the Labrador Current along the shelf.
Where is seismic anisotropy located beneath the Alps and the Apennines?
Authors: Pondrelli Silvia , Salimbeni Simone , Faccenda Manuele
Published: March 2020

A general review on measurements of upper mantle seismic anisotropy in the Alpine and Apennines region is now encouraged by the large amount of data produced by several projects (i.e AlpArray, Cifalps1). Geodynamic studies need to have a sketch of mantle flows that drives the evolution of a
tectonically active region. This is particularly important for the Italian peninsula, where several slabs have been involved in the Alps and Apennines building and where they are still interacts with the Adriatic plate. Draw mantle flows starting from seismic anisotropy requires to locate the source of what SKS phases detect. The answer, often undetermined, it is frequently hypothesized cross-checking different seismological observation. Overlapping SKS data with tomographic models in this region gives little help, because of the large differences in the shape, depth and dimension of fast bodies identified by different tomographic studies. Mapping and comparing SKSs data with other types of anisotropy measurements (Pn anisotropy, azimuthal anisotropy from surface waves tomography, crustal anisotropy) allow to discretise where fast anisotropy direction is much more probably astenospheric or where it pervades also regions at shallower depths.
V04 Level-1 data processing status for GRACE and GRACE Follow-On
Authors: Bandikova Tamara , Wen Hui Ying , Paik Meegyeong , Bertiger William , Miller Mark , Harvey Nate , McCullough Christopher , Finch Christopher , Byun Sung , Kuang Da , Landerer Felix , Boening Carmen
Published: March 2020

On May 22, 2020, the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), will celebrate two years of successful in-orbit operation. The primary goal of this satellite mission is to provide information about time variations of the Earth’s gravity field. This is possible due to precise orbit determination and inter-satellite ranging by determining the relative clock alignment of the USOs, precise attitude determination and accelerometry. High quality satellite observations are one of the fundamental requirements for successful gravity field recovery. NASA/Caltech Jet Propulsion Laboratory is the official Level-1 data processing and analysis center. The GRACE-FO Level-1 data are currently being processed with software version V04. This software will be used also for final reprocessing of the GRACE (2002-2017) Level-1 data. Here we present the analysis of two years of GRACE-FO sensor data as well as a preview of the reprocessed GRACE data, and discuss the measurement performance.
Mobile or not mobile: exploring the linkage between deep mantle composition and early Earth surface mobility
Authors: O'Farrell Keely A. , Trim Sean , Butler Samuel
Published: March 2020

Numerical models of mantle convection help our understanding of the complex feedback between the plates and deep interior dynamics through space and time. Did the early Earth have plate tectonics, a stagnant lid, or something in between? The surface dynamics of the early Earth remain poorly understood. Current numerical models of mantle convection are constrained by present-day observations, but the behavior of the hotter, early Earth prior to the onset of plate tectonics is less certain. The early Earth may have possessed a large hot magma ocean trapped near the core-mantle boundary after formation during differentiation, and likely containing different elements from the surrounding mantle. We examine how composition-dependent properties in the deep mantle affect convection dynamics and surface mobility in high Rayleigh number models featuring plastic yielding. Our Newtonian models indicate that increased conductivity or decreased viscosity flattens basal topography while also increasing the potential for surface yielding. We vary the viscosity, thermal conductivity, and internal heating in a compositionally distinct basal magma ocean and explore the compositional topography, insulation effects and surface stresses for non-Newtonian rheology. Models are run using a variety of crustal compositions, such as the inclusion of primordial continental material before the onset of plate tectonics. We monitor the surface for plate-like behavior. Since convective vigour is very strong in the early Earth, specialized tracer methods are employed for increased accuracy. In our models, Stokes flow solutions are obtained using a multigrid method specifically designed to handle large viscosity contrasts and non-Newtonian rheology.
Global scaling of observed sub-daily precipitation extremes to dewpoint temperature
Authors: Ali Haider , Fowler Hayley , Lenderink Geert , Lewis Elizabeth
Published: March 2020

The intensity and frequency of extreme precipitation events have increased globally and are likely to rise further under the warming climate. The Clausius-Clapeyron (CC) relationship (scaling) provides a physical basis to understand the relationship of precipitation extremes with temperature. Recent studies have used global sub-daily precipitation data from satellite, reanalysis and climate model outputs (due to the limited availability of long term observed sub-daily data at global scales) and have reported a higher sensitivity of sub-daily precipitation extremes to surface air temperature than for daily extremes. Moreover, at higher temperatures, moisture availability becomes the dominant driver of extreme precipitation, therefore, dewpoint temperature can be a better scaling variable to overcome humidity limitations as compared to air temperature. Here, we used hourly precipitation data from the Global Sub-daily Rainfall (GSDR) dataset and daily dewpoint temperature data (DPT) from the Met Office Hadley Centre observations dataset (HadISD) at 6695 locations across the United States of America, Australia, Europe, Japan, India and Malaysia. We found that more than 60% of locations (scaling estimated for individual location) show scaling greater than 7%/K (CC rate). Moreover, more than 55% of locations across Europe, Japan, Australia and Malaysia show scaling greater than 1.5CC. Furthermore, when locations across selected regions are pooled within similar climatic zones (based on Koppen Geiger classification), scaling curves show around 7%/K scaling. The scaling curves for locations at greater altitude (>400m MSL) are flat compared to locations at relatively lower altitude. The difference in scaling rates at-station and for pooled regions highlight the importance of understanding the thermodynamic and dynamic processes governing precipitation extremes at different spatial scales and indicate that local processes are driving the super-CC sensitivities in most regions.
A case of the lower secondary science teacher training course for improving knowledge about classification of igneous rocks
Authors: Arimichi Toshio , Kawamura Norihito
Published: March 2020

In Japan, lower secondary school students study classification of igneous rocks related to geomorphology of volcanoes in science classes.
Most of junior high school science teachers are not good at teaching about this field. It might be due to their poor study experiences in earth science. They studied basic geology only in elementary and lower secondary school science classes because upper secondary school science curriculum have not been covered all fields of science. Consequently, many science teachers prefer to show photographs of rock samples to their students and are apt to avoid instruction of observing rock for identification. This may cause disadvantage for their students to construct the knowledge about plutonism and volcanism. 
To improve instructional methods of basic petrology of igneous rocks, one of us conducted teacher training courses for lower secondary school science teachers. The results and subjects are as follows;
Firstly, an instructor showed three volcanic rocks (rhyolite, andesite, basalt) and three plutonic rocks (granite, diorite, and gabbro) to the trainees with no label. The trainees tried to classify the samples into some groups based on any points of views and present the results to others. Through this activity, the trainees would be aware of many points to divide igneous rock into some groups.
Secondly, the trainees observed and divided the igneous rocks into two groups on the basis of those textures. After the grouping, the trainees found the differences of colors among the rocks, and arranged in order from the white one in each group.
Thirdly, the trainees identified these rocks by utilizing a rock chart and references. 
Finally, an instructor talked to the school teachers about relations between diversity and chemical components of magma. 
According to a post questionnaires survey, some teachers replied as follows, "I knew the difference between the stones." "I did not know the points, now I knew it." " I had gained more confidence in instruction." “I feel that I have improved my teaching skills about this field.” In short, some trainees could improve their knowledge of basic petrology and instructional skills. 
It is necessary to conduct training for teachers in order to prevent disadvantages to the students based on the teachers' experiences . 
 I think it is necessary to increase the number of teachers who improve instructional methods of earth science (experimental observation) by conducting training to improve the skills of many teachers.

 
Locking Behavior of Main Marmara Fault in Western Turkey During Interseismic Period
Authors: Yılmaz Zeynep , Konca Ali Özgün , Ergintav Semih
Published: March 2020

The North Anatolian Fault (NAF) produced multiple earthquakes of M>7 throughout the 20th century, while the part of NAF beneath Sea of Marmara did not rupture during this period. Analysis of the Main Marmara Fault's interseismic behavior, the most active branch of the North Anatolian Fault in this region, in terms of locking depth and fault slip rate is critical for evaluating the region's seismic risk with a population of more than 20 million, as it provides information about the seismic moment deficit that may release in a potential future earthquake.

In this study, we modeled the Main Marmara Fault's interseismic locking with realistic geometry and 3D structure including sedimentary basins, by implementing a 3D finite element approach and using interseismic GPS velocities. We have optimized the fits with GPS data by evaluating cases where each fault segment is constrained by a fault slip rate below a predefined locking depth ranging from 0 to 20 km. Preliminary models reveal that a difference in locking depth is required between the Western Marmara and the eastern end of the Ganos Segment entering the Sea of Marmara. This result, which is consistent with seismicity studies and other previous studies using 1D profiles shows that the strain accumulation under Western Marmara is less and that the locking depths or couplings are not similar in these two segments. For the Princes' Islands Segment, further analysis is required due to complexity in the GPS data. Recent earthquakes along Silivri also indicate that the strain accumulation is complex with most mechanisms showing significant thrust component. We have also calculated various possible strain accumulation patterns and compared the strain rate field around the Main Marmara Fault. Our results show that in most cases the change in the seismicity of each segment is consistent with the interseismic behavior associated with its fault locking.

(This research has been supported by Boğaziçi University Scientific Research Projects Coordination Unit. Project Number: 15022, 2019)
Contributions to Jupiter's gravity field from dynamics in the dynamo region and deep atmosphere
Authors: Kulowski Laura , Cao Hao , Bloxham Jeremy
Published: March 2020

The antisymmetric part of Jupiter's zonal flows is responsible for the large odd gravity harmonics measured by the Juno spacecraft. Here, we investigate the contributions to Jupiter's odd gravity harmonics (J3, J5, J7, J9) from dynamics in the dynamo region and the deep atmosphere. First, we estimate the odd gravity harmonics produced by zonal flows in the dynamo region. Using Ferraro's law of isorotation, we construct physically motivated profiles for dynamo region zonal flow. We use the vorticity equation to determine the density perturbations associated with the flows and then calculate the odd gravity harmonics. We find that dynamo zonal flows with root mean square (RMS) velocities of 10 cm/s would produce J3 values on the same order of magnitude as the Juno measured value, but would not significantly contribute to J5, J7, and J9. Next, we examine the gravitational contribution from zonal flows above the dynamo region. We consider a simple model where the observed surface winds are barotropic (i.e., z-invariant) until they are truncated at some depth by some dynamical process, such as stable stratification and/or MHD processes. We find that barotropic zonal flow in the strongly antisymmetric northern (13°-26°N) and southern (14°-21°S) jets extending to the likely depth of a rock cloud layer or deep radiative zone can account for a significant fraction of the observed gravity signal.
Optimization of ambient seismic noise interferometry to monitor groundwater level variations.
Authors: Taruselli Marco , Arosio Diego , Longoni Laura , Papini Monica , Zanzi Luigi
Published: March 2020

 In this work, we test the cross-correlation of ambient seismic noise method in monitoring underground water variations. Within this perspective we applied the abovementioned technique to study the water table changes occurring both in areas exploited for drinking water needs and inside landslides. Into detail, surveys were carried out in Crépieux-Charmy and Ventasso water catchment fields and in the Cà Lita landslide, respectively. Our aim is to optimize the outcome of the method by studying the effect of different processing steps involved in the computation of the cross-correlation technique. For this purpose, we analyzed the influence of filter types and different time windows length. Additionally, in order to address the problem of localization of the change in the medium the seismic velocity variations have been also derived from limited frequency bandwidths according to the characteristics observed in the signals spectrum. This work has shown the potential of this methodology as a valuable non-destructive toll to accurately describe hydrogeological dynamics. The monitoring system could thus be coupled with the traditional tools to improve the reconstruction of the underground water variations.
Bayesian Finite-fault inversion for determination of rupture geometry and slip function
Authors: Davari Hamed , Ansari Anooshiravan , Vajedian Sanaz , Kheirdast Navid
Published: March 2020

In the finite-fault modelling we aim to invert the observed data to image the earthquake rupture inside the solid crust medium. The common finite fault inversion methods usually take a planar geometry for the ruptured area, however, evidences show more complicated geometries (e.g. 2016 Mw7.8 Kaikura) can causes the seismic event. Having the advanced remote sensing technologies (e.g. InSAR), with a high data resolution in the near fault area, we can increase the accuracy for determination of rupture geometry. In this study, we consider a large three dimensional ensemble of point sources in the solid crust medium, each point source can trigger six moment tensor components that makes the model space of the problem. We then find the most probable geometry of the ruptured area by inverting the interferometric observation for moment tensor components. Using the Bayesian inversion with MCMC (Markov Chain Monte Carlo) simulation the fault geometry and static slip deformation is determined from moment tensor to have a ruptured zone that maximizes the posteriori likelihood. The proposed method would be applied to 2019 M5.9 Torkamanchay earthquake in Iran and the preliminary results is presented.
Realization of time sequential estimation of terrestrial reference frame using square-root information filter and smoother
Authors: Chin Toshio Mike , Abbondanza Claudio , Gross Richard , Heflin Michael , Parker Jay , Soja Benedikt , Wu Xiaoping
Published: March 2020

The JTRF2014 realization of terrestrial reference frame has adopted a weekly time series representation that can track dominant non-linear station motions including periodic and random variations.  The realization is based on the Kalman filter and smoother algorithms whose time sequential nature would also be suitable for continuous updating of an existing frame as soon as new geodetic data become available.

As a part of preparation for the next reference frame realization, we have been examining alternative filter and smoother algorithms based on the square-root information filter (SRIF), known generally for improved numerical accuracy of the covariance matrix represented by a square-root matrix.

The new algorithms offer a number of other advantages over the conventional filter/smoother algorithms used in JTRF2014.  Namely, the new approach allows us to (1) avoid using some fictitious covariance matrix to initialize the filter, (2) avoid the random-walk constraints for the Helmert parameter sequences, and (3) handle cross-temporal EOP data such as the week-long segments reported by the SLR and DORIS networks.  We have also been enhancing the stochastic models of the station position motion to be used by the filter and smoother, including models for non-tidal deformation.
A catastrophic Late Pleistocene debris flow sourced in the glaciated High Atlas of Morocco
Authors: Hann Madeleine , Woodward Jamie , Hughes Philip , Rhodes Edward
Published: March 2020

Catastrophic events such as debris flows and big floods are important agents of landscape change in steepland mountain environments. These events can be prominent in paraglacial settings as well as those that are tectonically active.   Since such catastrophic events pose  a significant natural hazard in deglaciating modern settings (e.g. Haeberli et al. 2017), it is useful to better understand analogous events in the recent geological past.

The Tamatert Valley, near the village of Imlil, on the northern slopes of Jebel Toubkal (4167 m a.s.l.) in the High Atlas, holds a valuable record of Quaternary landscape change.  The steepland Tamatert Valley was glaciated during the Pleistocene (Hughes et al. 2018)  and lies on the major Tizi n’Test Fault Zone.

More than 200 well rounded basalt mega-boulders (>2m b axis) have been mapped in the Tamatert Valley catchment (9 km2). Many of the boulders are larger than 5 m (b axis). The mega-boulders are found in the active channel of the Tamatert River, stranded above the modern channel, and embedded in valley-fill deposits. A preliminary chronological framework, combining cosmogenic exposure and luminescence dating, points to deposition of these boulders in the Late Pleistocene. The boulders are porphyritic basalt and lithologically distinct from the local diorite/granite bedrock.  They were transported by a catastrophic flood or debris flow over a distance of more than 3 km from the glaciated basalt source area.

Serendipitously, a debris flow producing a similarly extensive deposit of boulders (up to 3 m b axis) occurred in the neighbouring Mizane Valley in September 2019. Mapping of this modern deposit allows direct comparison with the Late Pleistocene event. Together, these provide valuable insights into the geomorphological significance of high magnitude, large boulder transit events in glaciated, steepland river catchments in the High Atlas. 

Haeberli, W., Schaub, Y. & Huggel, C. 2017. Increasing risks related to landslides from degrading permafrost into new lakes in de-glaciating mountain ranges. Geomorphology, 293, 405–417
Hughes, P.D., Fink, D., Rodés, Á., Fenton, C.R. & Fujioka, T. 2018. Timing of Pleistocene glaciations in the High Atlas, Morocco: New10Be and36Cl exposure ages. Quaternary Science Reviews, 180, 193–213
Emergent constraints on global carbon-climate feedbacks from regional atmospheric aridity
Authors: Barkhordarian Armineh , Bowman Kevin W. , Cressie Noel , Jewell Jeffrey , Baehr Johanna
Published: March 2020

The vulnerability of terrestrial carbon sequestration to increases in fossil fuel emissions is one of the most important feedbacks in the Earth System.  However, the relative importance of temperature and moisture controls on regional terrestrial CO2 fluxes varies substantially and yet critical to unraveling their roles in carbon-climate feedbacks. Here, we employ the Hierarchical Emergent Constraint (HEC) to quantify an emergent relationship between spatially- explicit sensitivities of carbon fluxes to atmospheric aridity across an ensemble of Earth System Models (ESMs) and the long-term sensitivity of tropical land-carbon storage to atmospheric aridity.  Our results show that interannual fluctuations in atmospheric aridity, as an important driver of atmospheric water demand for plants, substantially impact the terrestrial carbon sink. However, this analysis, which is conditioned on observations, leads to a substantially lower feedback than predicted by ESMs alone. Furthermore, we show that a relatively small number of regions have an out-sized impact on global carbon climate-feedbacks.  These findings underscore the role of both water and temperature on carbon-climate feedbacks while the regional attribution provided by HEC points to areas for further process-based research.
Using 2D integrated water vapor (IWV) maps derived from GPS tropospheric path delays for augmenting Weather Research and Forecast (WRF) model predictions
Authors: Reuveni Yuval , Leontiev Anton
Published: March 2020

Water vapor (WV) is the most variable greenhouse gas in the atmosphere, which acts as a key feature in climate change studies and plays a crucial role in global warming. Its spatiotemporal distribution is necessary for understanding the hydrological cycle, and consequently can be used as an input factor in climatological studies at global, regional, and local scales. Integrated water vapor (IWV), which is defined as the amount of vertically integrated water vapor, can also augment atmospheric modeling at local and regional scales because it is frequently used in energy budget and evapotranspiration assessments. Currently, there are numerous existing atmospheric models which are able to estimate IWV amount, nevertheless, they fail to obtain extremely accurate results compared with in-situ measurements such as radiosondes. Here, we present a new methodology for improving Weather Research and Forecast (WRF) model predictions accuracy, by using data assimilation technique, which combines estimated 2D IWV regional maps, derived from GPS tropospheric path delays, along with the WRF numerical model output to generate an optimal approximation of the evolving sate of the system. This is done as opposed to pervious works, which assimilated single point measurements, either from radiosondes or GPS zenith wet delay (ZTD) estimation, demonstrating some extant of improvement in the WRF prediction accuracy compare to the standalone WRF numerical runs. Using the suggested technique, our results shows a decrease of up to 30% in the root mean square difference relative to the radiosonde data for WRF predictions assimilated with 2D GPS-IWV regional maps compare to the standalone WRF numerical runs.