bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing analytical tsunami fragility functions for Italian coastal communities
Authors: Del Zoppo Marta , Di Ludovico Marco , Prota Andrea
Published: March 2020

In a probabilistic tsunami risk assessment framework, the definition of vulnerability of the physical assets of coastal communities plays a fundamental role. Therefore, current research is moving towards the definition of a general methodology for developing analytical tsunami fragility functions for the physical assets to be used in loss-assessment frameworks at community scale. Herein a methodology is proposed for developing analytical tsunami fragility functions and its application on an inventory of RC buildings representative of the Mediterranean coastal communities is illustrated. Simple mechanics-based models are defined for the damage assessment of reinforced concrete (RC) buildings with breakaway infills under tsunami lateral loads. A simulated design procedure is adopted for the definition of the buildings inventory, relying on Monte Carlo simulation to account for geometrical and mechanical uncertainties. One key feature of the approach is that intermediate damage states prior to collapse are defined to account for light/moderate damage to both structural and non-structural components subjected to tsunami onshore flows.
Robust expression of ENSO throughout the Last Interglacial
Authors: Thomas Zoe , Turney Chris , Kershaw A. Peter , Jones Richard , Croudace Ian , Moss Patrick , Herbert Timothy , Grosvenor Mark , Wust Raphael , Muller Joanne , Kylander Malin , Rule Susan , Lewis Sophie , Coulter Sarah , Mudelsee Manfred
Published: March 2020

The El Niño-Southern Oscillation (ENSO) is a driver of global atmosphere-ocean dynamics, but projections of frequency and magnitude in different climate states remain uncertain. Palaeoclimate records offer the potential to improve our understanding of ENSO behaviour but most are fragmentary, suffer low resolution, and/or typically do not cover periods warmer than present day. The Last Interglacial (129-116 kyr BP) was the most recent period during which global temperatures were close to 21st century projections, and potentially provides insights into operation of climate modes of variability in the future. Here we report a continuous, inter-annually resolved record of hydroclimate spanning 220-80 ka from Lynch’s Crater in tropical northeast Australia, a region highly sensitive to ENSO. Our reconstruction is based on a micro-X-ray fluorescence (XRF)-generated elemental profile at 200 µm resolution, combined with loss-on-ignition, magnetic susceptibility, and pollen analysis. We find that during globally warmer periods (including super-interglacial Stage 5e, and 5c), there are significantly larger amplitudes in high-frequency ENSO spectral range (3-8 years), which are absent from the record during the glacial stages MIS6 and MIS4. Our results imply an ENSO dependence on mean climate, with enhanced ENSO variance during interglacials globally warmer than present. These results are consistent with climate model projections for a future slowdown of the Walker circulation and more extreme El Niño events under greenhouse warming.
Research on the construction of knowledge base system of Marine disasters and emergencies risk prevention and control
Authors: Wu Le , Xu Fei , Sun Lie
Published: March 2020

Marine environmental security are facing increasingly prominent problems in recent years. Under the current context of big data, most of the emergency event participants are in a dual dilemma of "knowledge ocean" and "knowledge deficiency" in their responses to emergencies, leading to a result that they fail to quickly acquire and use relevant knowledge. For the need of risk prevention and control over marine environmental security events, it is necessary to make research on the knowledge base of marine environmental security risks’ prevention and control and organize the knowledge base system based on the knowledge related to storm surges, enteromorpha, marine oil spills, tsunamis, sea ice and other marine environmental security events, including such contents as basic knowledge, laws and regulations, plans, cases, prevention and preparation, monitoring and early warning, disposal and rescue, and so on. Through such methods as knowledge maps, multi-type knowledge coupling, digitization of risk prevention and control knowledge and the like, the ontology and detailed element sets are constructed for the knowledge base on prevention and control over comprehensive risks against marine environmental safety, thus forming the entity of the risk prevention and control knowledge base.
New topside ionosphere model based on Vary-Chap function using radio occultation and topside sounder data
Authors: Wu Mengjie
Published: March 2020

The Global Navigation Satellite System (GNSS) radio occultation and topside sounder provide materials for the validation of a mathematical description of the topside ionosphere up to satellite altitude. An attempt to represent the topside electron density profile is using α-Chapman function with a continuously varying scale height. In this study, the Vary-Chap scale height profiles are obtained based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) electron density profiles from 1 January 2008 to 31 December 2013 and fitted by a shape function composed of two weighted patterns representing the ion and electron contributions of lower and higher altitudes. The topside profiles of ISIS-1 data are used to define the transition height of different ions. The associated fitting parameters are analyzed to reveal their temporal and spatial features and variations along with enhancement of solar activity. Their prominent dependence on latitudes, longitudes, the local time, the season, and the solar cycle facilitates modeling of the Vary-Chap scale height in constructing empirical topside ionospheric models.
Homogenizing visually observed cloud cover over global oceans with implications for reconstructions of radiative fluxes at sea surface
Authors: Gulev Sergey , Aleksandrova Marina
Published: March 2020

We consider here the potential of Voluntary Observing Ship (VOS) observations available form the ICOADS for estimating ocean surface heat budget at centennial time scales. VOS provide the longest coverage of the World Ocean by in-situ meteorological observations in time going back to the mid 18th century. We concentrate here on the shortwave and longwave radiative fluxes, largely relying on cloud cover. Visually observed cloud cover reports from Voluntary Observing Ships (VOS) and assimilated in ICOADS are were used to build long-term time series of cloud cover and short-wave radiation characteristics over the ocean for the last century. Cloud cover reports from VOS are subject for a number of inhomogeneities and uncertainties. Considering the centennial perspective, in 1949, WMO changed the practice of reporting cloud cover from tenths to octas. Moreover, some additional uncertainties were inherent in the early 20th century reports. This resulted in a definite break in cloud cover time series which further propagate to the inhomogeneity of the reconstructed time series of shortwave and longwave radiative fluxes. This inhomogeneity was associated with (while not limited to) the biased convertionconversion of tens to octas when developing ICOADS records using IMMA (and earlier generation formats). In this convertionconversion octa values “2” and “6” consolidated values corresponding to 2 and 3 tens and 7 and 8 tens respectively, thus making the fractional cloud cover distribution peaked to 2 and 6 octas. In order to remove correct this bias and to homogenize cloud cover time series we developed a new method based upon a discrete probability distribution for fractional cloud cover. Applying analytical distribution, we provide the correction of cloud cover reports and arrive to homogeneous time series of cloud cover. Further homogenized times series of cloud cover were used for computing radiative fluxes over the global ocean for the period from 1900 onwards.
Modeling and evaluation of the effect of afforestation on the runoff generation within the Glinščica catchment (Slovenia)
Authors: Johnen Gregor , Sapač Klaudija , Rusjan Simon , Zupanc Vesna , Vidmar Andrej , Bezak Nejc
Published: March 2020

Modeling and evaluation of the effect of afforestation on the runoff generation within the Glinščica catchment (Slovenia)

Gregor Johnen1, Klaudija Sapač2, Simon Rusjan2, Vesna Zupanc3, Andrej Vidmar2, Nejc Bezak2

1 Radboud University Nijmegen, Faculty of Science

2 University of Ljubljana, Faculty of Civil and Geodetic Engineering

3 University of Ljubljana, Biotechnical Faculty

 

Abstract:

Increases in the frequency of flood events are one of the major risk factors induced by climate change that lead to a higher vulnerability of affected communities. Natural water retention measures such as afforestation on hillslopes and floodplains are increasingly discussed as cost-effective alternatives to hard engineering structures for providing flood regulation, particularly when the evaluation also considers beneficial ecosystem services other than flood regulation. The present study provides combined modelling approach and a cost-benefit analysis (CBA) of the impacts of afforestation on peak river flows and on selected ecosystem services within the Glinščica river catchment in Slovenia. In order to investigate the effects, the hydrological model HEC-HMS, the hydraulic model HEC-RAS and the flood damage model KRPAN, that was developed specifically for Slovenia, are used. It was found that increasing the amount of tree cover results in a flood peak reduction ranging from 9-13 %. Flood extensions were significantly lower for most scenarios leading to reduced economic losses. However, a 100-years CBA only showed positive net present values (NPV) for one of the considered scenarios and the benefits were dominated by the flood regulation benefits, which were higher than for example biodiversity or recreational benefits. Based on our findings we conclude that afforestation as a sole natural water retention measure (NWRM) provides a positive NPV only in some cases (i.e. scenarios) and if additional ecosystem co-benefits are considered.
The spectrum of ecosystem functional properties
Authors: Migliavacca Mirco , Musavi Talie , Mahecha Miguel D. , Nelson Jacob A. , Knauer Juergen , Baldocchi Dennis D. , Perez-Priego Oscar , Reichstein Markus ,   Ecosystem Functional Properties group
Published: March 2020

Understanding the coordination of ecosystem functions across biomes and climate is still a major challenge that hampers our ability to properly predict biosphere response to climate change. Theories such as the leaf economics spectrum and the least cost investment strategy postulate that plants optimize the rate of investment in transpiration, photosynthetic capacity, and nitrogen (N) allocation dependent on the ratio of their costs to gain given their resources and environment.

In this contribution we test whether theories about functional traits coordination at leaf and organs level are emerging at ecosystem scale. We further investigate the existence of a global spectrum of ecosystem functional properties, and analyze how state of the art terrestrial biosphere models reproduce the spectrum.

To do so we used data of CO2, water and energy exchange for 164 sites (1237 site years) from the FLUXNET LaThuile and FLUXNET 2015 datasets with at least 3 years of data. For 61 sites, we were able to compile site information on canopy-scale measurements of foliar N concentration, maximum leaf area index , and stand age, from the literature.

We find evidence that a global spectrum of ecosystem functional properties exist, and that most of the variability (66.2%) is captured by three dimensions. The first dimension represents ecosystem productivity; the second the water availability gradient, and climate limitations to productivity; the third dimension reflects ecosystem respiration potential and carbon-use efficiency and is related to aridity and stand age and disturbance regimes. The first two dimensions of the spectrum are well captured by ecosystem models, while the third dimension is poorly reproduced. This might be related to the spin up of the models (steady-state condition) or to an incomplete representation of processes related to age that might limit the ability of models to accurately predict the dynamic carbon, water and nutrient cycling in ecosystems in disturbed areas.

Finally, we show across ecosystems globally that leaf level theories can be in some cases translated to the ecosystem scale. As a main example we found an inverse relationship between photosynthetic N and water use efficiency as postulated by the least cost investment theory across FLUXNET sites. However, this is possible only when the contribution of vegetation is properly accounted for, and evaporation from soil and wet surfaces is removed from the analysis. This highlights that emerging biological patterns at ecosystem scale might be masked by other factors related to physical rather than biological responses.
The role of volcanism for abrupt climate change during the last glacial period
Authors: Svensson Anders , Lohmann Johannes , Rasmussen Sune Olander , Buizert Christo
Published: March 2020

During the last glacial period, abrupt climate events known as Dansgaard-Oeschger (DO) and Heinrich events have been observed in various types of Northern Hemispheric (NH) paleoclimate archives. It has been speculated that volcanism may play a role in the abrupt climate variability of the last glacial period, for example as a trigger of abrupt changes. The investigation of a possible link between abrupt climate events and volcanic eruptions has been hampered by the lack of a global volcanic eruption record from the last glacial period. A recent identification of 80 major bipolar volcanic eruptions in Greenland and Antarctic ice core records within the interval 12-60 ka BP now enables us to investigate this link.

Using high-resolution ice-core records of climate (δ18O), atmospheric circulation changes (calcium) and volcanic eruptions (sulfate and other volcanic proxies) we investigate the timing of abrupt climate events and large volcanic eruptions at decadal resolution. We consider possible links between major volcanic eruptions and DO onsets (NH warming), DO terminations (NH cooling), and Heinrich stadials (strong NH cooling). Heinrich stadials are cold Greenland stadial periods during which Heinrich events occurred; large Hudson Strait iceberg discharge events that are characterized by deposition of significant amounts of ice rafted debris in North Atlantic marine sediments.

Significant links of volcanic and climatic events are tested in a statistical framework under the null hypothesis of random and memoryless volcanic activity. Our analysis shows that while certainly not all abrupt climate change of the last glacial period is associated with volcanism, we find that volcanism may have induced some abrupt Greenland warming events and perhaps several of the extreme North Atlantic cold Heinrich stadials; no significant link is found between volcanism and DO terminations. We speculate that volcanic cooling can drive such transitions when the coupled system of Atlantic Ocean circulation and North Atlantic sea ice is close to a tipping point.
Auroral electrodynamics---investigation by a dual sounding rocket experiment
Authors: Akbari Hassanali , Pfaff Robert ,   Auroral Jets Sounding Rocket Experiment Team
Published: March 2020

We present results from a 2017 sounding rocket experiment in which two NASA sounding rockets were simultaneously launched into the auroral ionosphere. The rockets included comprehensive instrumentation to measure DC and AC electric fields, magnetic fields, energetic particles, plasma density, and neutral winds, among other parameters, and achieved apogees of 190 and 330 km. This unprecedented collection of in-situ measurements obtained at two altitudes over an auroral arc, along with conjugate ground-based measurements by the Poker Flat incoherent scatter radar and all-sky cameras, enable us to investigate the behavior of an aurora arc and its associated electrodynamics. A prominent feature of our observations is the presence of localized, large-amplitude Alfvén wave structures observed in both the electric field and magnetometers at altitudes as low as 190 km in the vicinity of up- and down-ward current regions. The observations are discussed in the context of ionospheric feedback instability. The results are compared to predictions of previously published numerical studies and other sounding rocket observations.
AN UNSUPERVISED SOIL MOISTURE ESTIMATION MODELLING APPROACH USING C-BAND DUAL PolSAR DATA
Authors: Tiwari Reet Kamal , Tripathi Akshar
Published: March 2020

With the advent of remote sensing and its widescale implementation in the field of agriculture and soil studies, today remote sensing has become an integral non-evasive analysis and research tool. After decades of research with conventional optical remote sensing, both airborne and spaceborne, a need was felt to have an all-weather remote sensing data availability. Spaceborne SAR (Synthetic Aperture RADAR) or microwave remote sensing with its all-weather availability and high temporal resolution, owing to its penetration capabilities has been found highly suitable for the soil and crop health studies. Since, SAR remote sensing is highly sensitive to surface roughness and dielectrics in dry and moist soil conditions respectively, it becomes highly important to study and observe the variations of these properties in various polarisation channels. PolSAR (Polarimetric SAR) data with its different decomposition models has an advantage over conventional SAR data since it uses more than one polarisation channels and polarimetric decomposition models which consider several soil and crop parameters. This helps to study the RADAR wave interaction with the target easier. This helps in the proper and better study and understanding of retrieval of soil moisture and analysis of its variation over time. This study makes use of C-band Sentinel 1A satellite dual PolSAR, time series data of VV and VH polarisations. The datasets used are that of pre-monsoon and monsoon period of 2019, February to May respectively for Rupnagar area. In this study it has been aimed to model for retrieval of soil moisture based on RADAR backscatter values and Normalised Differential Moisture Indices values from Sentinel-1A and Sentinel 2 satellite imageries respectively. The process has been performed on both VV and VH polarisations and the results are analysed for both the time periods. Theoretically, it has been observed that VH polarisation yields better and nearer to ground truth results with least Root Mean Squared Error (RMSE) of 0.05 and high R2-Squared statistics of 0.72 (72%) in training and testing. This study aims at unsupervised modelling using satellite datasets for model development, training and validation and without the input of field data. The results though not very good yet give an idea of soil moisture estimation and is highly beneficial for areas and conditions when field validations and data collection is difficult or not possible. This study also aims at reducing field validation dependence. Once integrated with field data, accuracy is expected to increase.
The South China and Indochina neighborhood in the assembled Gondwana
Authors: Yao Weihua , Wang Jian , Spencer Christopher , Martin Erin , Li Zheng-Xiang
Published: March 2020

Investigations on the late Neoproterozoic to early Paleozoic sedimentary strata of western South China and northern Indochina reveal a provenance affinity between the two, which was mainly derived from the local western part of South China. The newly discovered provenance featured differently from that of the typical Indian-Australian Gondwana siliciclastic source. Basin types and sedimentation histories of the two sedimentary basins in western South China and northern Indochina are also comparable. Furthermore, previous studies discovered the geochronological, petrological and geochemical similarities of the early Paleozoic magmatic rocks between these two regions, suggesting a connection between the two during the subduction of the proto-Tethys ocean towards the northern Gondwana and the accretion of Asian continents onto the Gondwana mainland. Utilizing all such geological information, we speculate in this study that South China and Indochina were probably in the neighbourhood on the northern Gondwana margin when the Gondwana semi-supercontinent was assembled. Specifically, Indochina was likely located to the southwest of South China during the late Neoproterozoic to early Paleozoic. Apart from sedimentation, neither Indochina nor the western part of South China got much deformational and metamorphic impaction from the collision between South China and northern Gondwana during that time.
Characterization of Extreme precipitation over India
Authors: Gupta Neha , Chavan Sagar
Published: March 2020

This study characterizes gridded precipitation data over India in terms of presence of potential temporal trends and their upper tail properties. Daily gridded precipitation data having resolution of 0.25° prepared by Indian Meteorological Data (IMD) for a record period of 110 years (1901–2010) over entire India is used for the analysis. The objectives of this study are (i) to assess presence of potential trends in annual maximum daily precipitation series by using a variety of non-parametric methods and (ii) to investigate the upper tail behavior of daily precipitation series. Detailed trend detection analysis is carried out to find abrupt change/step or monotonic trend using a variety of non-parametric and graphical methods. Detection of abrupt change/step in the data is accomplished through Modified Pettitt’s test whereas the monotonic trends are examined by applying different tests, such as original and modified Mann Kendall (MK) tests, Spearman rank correlation (SRC), Block bootstrap (BBS) with MK and SRC and innovative trend analysis (ITA). Quantitative assessment of monotonic trend is performed based on Sen’s slope method. The implication of change magnitude is studied in terms of percentage change over mean.  Further, the upper tail behaviour of annual maximum daily precipitation series is tested based on the framework of generalized extreme value (GEV) theory. Subsequently, the behaviour of extremes in the precipitation data is diagnosed in terms of their frequency of occurrence by using a state-of-the-art algorithmic procedure which is a graphical method, famously known as Mean Excess Function (MEF). Finally, Multi-criteria decision – making (MCDM) techniques are used for identification of critical regions in terms of behaviour of extremes (i.e., increasing or decreasing trend, change magnitude, upper tail properties) over India.
Sources and Sinks of Nitrated Phenols: Application of an Observation-based Model
Authors: Peng Yuwen
Published: March 2020

Sources and Sinks of Nitrated Phenols: Application of an Observation-based Model

Yuwen Peng1, Sihang Wang1, Caihong Wu1, Jipeng Qi1, Chaomin Wang1,
Wei Song2, Xinmin Wang2, Bin Yuan1,*, Min Shao1,**

1 Institute for Environmental and Climate Research, Jinan University, 511443 Guangzhou, China

2 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China

* byuan@jnu.edu.cn

** mshao@pku.edu.cn

 

Abstract: Nitrated phenols are one of the intermediate products of aromatics oxidation that has been proved to be phytotoxic, mutagenic and important components of brown carbon and SOA in the atmosphere. Although its sources and sinks have been reported, high-time-resolution measurements of nitrophenols and the evaluation of reported rate constants insufficient. In this paper, we measured the concentration of nitrated phenols at an urban site in Guangzhou, then we use an observation-based model to compare different photolysis frequencies of nitrophenol and analyze its budget. The primary emission of traffic seems to be the dominant factor when considering its diurnal profile. Photolysis has proved to be the dominant sink of nitrophenol in the atmosphere.
Microplastic contamination in remote alpine lakes
Authors: Gateuille David , Dusaucy Julia , Gillet Frédéric , Gaspéri Johnny , Dris Rachid , Tourreau Grégory , Naffrechoux Emmanuel
Published: March 2020

Since their first detection in the 1970s, microplastics have been a growing concern in public opinion. Although a large number of studies are interested in this contamination, the fate of microplastics in freshwater remains poorly understood. In particular, the identification of sources, the degradation processes of these compounds and their impacts on aquatic ecosystems constitute fields of research to be investigated. PLASTILAC is the first project focusing on the presence and fate of microplastics in 4 remote alpine lakes (Muzelle Lake, Vert Lake, Pormenaz Lake and Anterne Lake) that have been investigated during summer 2019. The aims of this study were to better understand the microplastic dynamics in small remote lake catchment and to quantify the impacts of various anthropic activities on the microplastic contamination.

The lakes were chosen to allow the comparison of the different transfer processes occurring at the catchment scale. Thus, the lakes of Muzelle and Anterne have similar sizes (about 10 000m²) and altitudes (about 2100 m a.s.l). These two lakes are isolated and have no direct access apart from several hour hikes. They are however separated by a distance of about 120 km. A comparison of their contamination levels therefore makes it possible to assess the background contamination at the scale of the Northern Alps. On the contrary, the Anterne, Pormenaz and Vert Lakes are very close but cover a wide gradient of altitude (from 1260 to 2100 m a.s.l.) and of exposure to anthropogenic activities. Their comparison allows us to study the influence of distance from potential sources on the microplastic contamination.

To investigate the dynamics of microplastics at the lake basin scale, a multi-compartment approach was implemented. The water column was sampled using a specially designed boat that allowed the filtration of the large volumes (approximately 200 cubic meters) of water required in lightly contaminated environments. The boat was equipped with a 50 µm mesh. A similar system was used to sample the lake outlets and determine the outflows of microplastics. In order to quantify the incoming flows, an atmospheric fallout collector was also installed. Finally, lake sediments were collected to quantify the fraction of microplastics eliminated from the water column through sedimentation. All of these data made it possible to establish a mass balance of microplastics at the scale of the watershed of lakes and to determine the characteristic times of contamination.

Although analyzes are still in progress, the first results show that even the most distant lakes from anthropogenic sources have significant microplastic contamination of the order of 1 particle per cubic meter. Due to the distance to the sources, the microplastic pollution was constituted fibers while fragments and micro-beads could not be observed. 
The variational echo tracking method and its application in convective storm nowcasting
Authors: Wu Jiankun , Chen Mingxuan , Qin Rui , Gao Feng , Song Linye
Published: March 2020

The objective extrapolation forecast is the main method for 0-1 hour convective storm nowcasting. Radar echo extrapolation was performed by using the 6 minute interval radar mosaics obtained from the radar images of 8 multi-radars in Beijing-Tianjin-Hebei region. A comparative study of two extrapolated forecasts of eighteen typical convective precipitation events occurred in Beijing-Tianjin-Hebei region from 2016 to 2018 was conducted. Compared with the tracking radar echoes by correlation method, the variational echo tracking method utilizes variational technique to compute the motion vector fields, and uses two strict constraints to get a better motion vector field. The results indicated that the variational echo tracking method performed better in prediction of the radar echo pattern, echo location, and echo intensity at 30- and 60-min forecast lead times: 1) A comparative study of the two extrapolated forecasts of four precipitation events in Beijing-Tianjin-Hebei region was conducted. The result indicated that the radar echo location, the echo pattern and echo intensity produced by the variational echo tracking method were closer to the real observation within one hour. 2) Quantitative evaluation for the two extrapolated forecasts of the eighteen typical convective precipitation events was conducted. Compared with the tracking radar echoes by correlation method, the probability of detection and the critical success index of the 30- or 60-min extrapolated forecast produced by the variational echo tracking method were higher, meanwhile the false alarm rate was lower when the radar echo threshold was 35dBz and 45dBz. Also, a quantitative evaluation classified by the weather type indicated that the variational echo tracking method performed better than the tracking radar echoes by correlation method in most weather types.
Wind wake effects of large offshore wind farms, an underrated impact on the marine ecosystem?
Authors: Schrum Corinna , Akhtar Naveed , Christiansen Nils , Carpenter Jeff , Daewel Ute , Djath Bughsin , Hieronymi Martin , Rockel Burkhardt , Schulz-Stellenfleth Johannes , Schultze Larissa , Stanev Emil
Published: March 2020

The North Sea is a world-wide hot-spot in offshore wind energy production and installed capacity is rapidly increasing. Current and potential future developments raise concerns about the implications for the environment and ecosystem. Offshore wind farms change the physical environment across scales in various ways, which have the potential to modify biogeochemical fluxes and ecosystem structure. The foundations of wind farms cause oceanic wakes and sediment fluxes into the water column. Oceanic wakes have spatial scales of about O(1km) and structure local ecosystems within and in the vicinity of wind farms. Spatially larger effects can be expected from wind deficits and atmospheric boundary layer turbulence arising from wind farms. Wind disturbances extend often over muliple tenths of kilometer and are detectable as large scale wind wakes. Moreover, boundary layer disturbances have the potential to change the local weather conditions and foster e.g. local cloud development. The atmospheric changes in turn changes ocean circulation and turbulence on the same large spatial scales and modulate ocean nutrient fluxes. The latter directly influences biological productivity and food web structure. These cascading effects from atmosphere to ocean hydrodynamics, biogeochemistry and foodwebs are likely underrated while assessing potential and risks of offshore wind.

We present latest evidence for local to regional environmental impacts, with a focus on wind wakes and discuss results from observations, remote sensing and modelling.  Using a suite of coupled atmosphere, ocean hydrodynamic and biogeochemistry models, we quantify the impact of large-scale offshore wind farms in the North Sea. The local and regional meteorological effects are studied using the regional climate model COSMO-CLM and the coupled ocean hydrodynamics-ecosystem model ECOSMO is used to study the consequent effects on ocean hydrodynamics and ocean productivity. Both models operate at a horizontal resolution of 2km.
How can climate change modify the carbon stock of forest soils?
Authors: Horváth Adrienn , Bene Zsolt , Gálos Borbála , Bidló András
Published: March 2020

Organic matter, the most complex and heterogeneous component of soil. SOM is a very relevant indicator for soil quality, as it can change the behavior and direction of many properties, soil functions, transformation processes. Less water reduces the amount of biomass produced, resulting in lower production and less plant residue in the soil. Under drier conditions, organic matter decomposes faster due to dominant aerobic processes, thereby reducing soil organic matter content. As the temperature rises, the rate of degradation processes and the intensity of soil respiration increases, which may further increase the reduction of soil carbon stock. Our forests are under high pressure due to climate change, especially in the Carpathian Basin. Therefore, beech and sessile oak are expected to replace with Turkey oak and the afforestation may lead to a change in carbon storage of forests.

To create a database and estimate the changes, we measured the carbon stock of soil in three different regions in Hungary, where the research sites formed on loess bedrock, on 150 and 250 m a.s.l., 650-710 mm precipitation sum with 10-10.4 °C annual temperature.

We took a 1.1 m soil column with soil borer and divided it into 11 samples in each column. Physical (texture, bulk density, water holding capacity) and chemical (pH, CaCO3) soil properties and SOM were determined based on the methods of the Hungarian Standard in the soil laboratory.

During the evaluation, the amount of SOC was the highest in the topsoil layers. In summary, we found a larger amount (104 C t/ha) of SOC in the soil of stands, where sessile oak were the main stand-forming tree species. The amount of carbon was lower where turkey oak was dominant in sessile oak stands (70 C t/ha on average).

To conclude, the SOC order in case of the stand-forming tree species: sessile oak (/hornbeam) > beech > Turkey oak. We detected that different forest utilization and tree species have an effect on the forest carbon as the litter as well (amount, composition). Our measurements are not representative of the whole stand, but the homogenous loess bedrock demonstrates the impact of different mixture forests on carbon stock. After all, vegetation depends on site conditions (e.g. moisture) and not vice versa. The effects of future climatic changes on soil carbon storage are difficult to predict. In the future, it would be important to expand the use of continuous forest cover farming modes.
Future projections of photovoltaic power generation on climate change simulated by CORDEX II multi-RCMs over East Asia
Authors: Park Changyong , Cha Dong-Hyun , Shin Seok-Woo , Kim Gayoung , Kim Taehyung
Published: March 2020

East Asia is a highly industrialized region with high CO2 emissions from fossil fuel use. Therefore, to achieve the goal of the Paris Agreement on CO2 reduction, an increase in the production of renewable energy such as photovoltaic (PV) and wind power generation is required in this region. Most renewable energy production is directly affected by weather and climate. This study projected changes in future PV power generation and climate variables affecting them using CORDEX phase 2 RCMs with 25km horizontal resolution forced by HadGEM2-AO GCM over East Asia. The present change and future projection of PV potential production (PVpot) depend critically on changes in surface-downwelling shortwave radiation (RSDS). In the analysis of recent changes in PVpot over East Asia using the ERA5 reanalysis data, PVpot overall increased slightly. For PVpot projections using the high-emission scenario during the late 21C, RegCM4 is expected to increase, while the other RCMs will decrease. The results of this study will help to develop policies for efficient future production of renewable energy over East Asia by presenting the projection of future photovoltaic power generation on a detailed regional scale.
Introduction to Mars Analog Mission: AMADEE20 and Exploration Cascade
Authors: Ozdemir Seda , Groemer Gernot , Garnitschnigg Stefanie
Published: March 2020

Analog missions are the windows to future exploration to different planetary surfaces, e.g., Mars, the Moon, and asteroids, by playing a tremendous role in problem-solving, know-how and lesson learned in space research. AMADEE-20 is the Mars Analog Mission of the Austrian Space Forum (OEWF), will be held in Ramon Crater-Negev Desert, Israel between 15 October and 15 November 2020. The mission is mainly in fields of geosciences, astrobiology, engineering, life sciences, communications, and medical applications. Moreover, it provides data on the limitations and strengths of human-robotic exploration at every stage of the mission and, presents how to combine those two significant components for the scientific explorations. 

Ramon crater provides similarities to various Mars surface features, e.g., typical terrain with a wide range of sand-rocky surface and inclination, for the 13th mission of OeWF. AMADE-20 has already come forward with its mission architecture development and its evolving algorithm “Exploration Cascade” which is defining an efficient deployment sequence, providing a framework for the search of life on Mars (space analogies). It was first demonstrated at the last mission AMADEE-18 (Oman, February 2018) and became a critical methodological tool for AMADEE-20. Notably, this model provides a solid layout for all future analog missions by bridging different parties to avoid the human-robotic missions’ complexities, taking into account instrument requirements, flight planning border conditions, environmental dynamics and (ground-based) data processing pipeline limitations. This workflow defines when and where to deploy instruments, expected data transfer times to the Mission Support Center on Earth and how fast the data processing can lead to knowledge influencing the decision-making processes of the flight planning teams.

Here, we would like to present our upcoming analog mission; AMADEE-20 and discuss the mission development processes with all aspects including the Exploration Cascade.
Recovering P from a eutrophic lake via hypolimnetic withdrawal and purification
Authors: Silvonen Soila , Niemistö Juha , Nurminen Leena , Aurola Anne-Mari , Malin Ismo , Kotakorpi Matti , Horppila Jukka , Jilbert Tom
Published: March 2020

Hypolimnetic withdrawal (HW) is a restoration method for eutrophied lakes that aims to remove phosphorus (P) and other nutrients from the system. It is conventionally carried out by pumping or siphoning nutrient-rich bottom water to the discharge of the lake during periods of thermal stratification. However, there is growing interest in developing closed circuit modifications of HW in which nutrients could be captured and the purified water returned to the same lake. This would tackle some problematic aspects of conventional HW, and additionally enable the capture and recycling of P stored in lakes.
A pilot closed circuit HW system has been constructed at a eutrophic dimictic lake located in Southern Finland. This hypolimnetic withdrawal and purification circuit (HWPC) consists of a withdrawal pipe installed at the lake deep, a treatment and filtering unit on shore, and a wetland. In the treatment unit, P is first precipitated and then captured by sand filters, while the purified water flows subsequently through a wetland and finally back into the lake.
In the current study, we investigated the pool of potentially removable P in the study lake, the optimal timing of HW within the annual cycle, and the functioning of the HWPC. The P retention capacity of the purification unit and the composition of the precipitate trapped in the filters were both examined. The results showed that P accumulation in the near-bottom water of the study lake during thermal stratification is substantial, allowing significant amounts of P to be removed from the lake via HW. The concentration of total P of the water entering the HWPC was over 300 µg/L, of which the system captured more than 80%. The P content of the precipitate trapped in the filters varied between 6-12 g P/kg, and consisted of both iron and calcium-bound P phases. These results imply that it is possible to recover P accumulated in eutrophied lakes for potential recycling purposes.
First Field-Test results of iGNSS-R instrument of the PRETTY payload
Authors: Dielacher Andreas , Fragner Heinz , Moritsch Michael , Wickert Jens , Koudelka Otto , Hoeg Per , Cardellach Estel , Martin-Neira Manuel , Semmling Maximilian , Walker Roger , Hörmer Andreas , Wenger Manuela
Published: March 2020

The PRETTY mission is a 3U CubeSat mission, hosting two different payloads, a radiation dosimeter and an interferometric GNSS reflectometer. The intended launch is planned in 2022.

The reflectometer payload has been built, using flight representative hardware and mounted inside a portable setup. Two campaigns have been carried out, a first one to verify the setup in real world condition and the second one to record reflectometry data over the Danube river. The reflections over the river are analyzed and compared to a reference data set obtained from basemap.at (which is released under Open Government Data Österreich Lizenz CC-BY 4.0).

The hardware is capable of generating complex and power waveforms at the same time, and the reflection events are visible in both. Since PRETTY is aiming for phase altimetry, only coherent measurements are conducted with an integration time of 20ms .

The re-tracking algorithm for the specular point and height estimation are based on [1]. Due to the low elevation angle and receiver height, the effects from the ionosphere is not considered , however effects from the atmosphere have to be included in the data re-tracking process. The reflection peaks, and the signal to noise ratio of the peaks, are large enough detect the peak and to calculate the height of the reflection point. The height retrieval is shown in the paper.

The results are promising w.r.t. the performance of the overall structure of the PRETTY GNSS-R payload  in order to deliver altimetry results on a low-cost CubeSat platform.

[1] W. Li, E. Cardellach, F. Fabra, S. Ribó and A. Rius, "Assessment of Spaceborne GNSS-R Ocean Altimetry Performance Using CYGNSS Mission Raw Data," in IEEE Transactions on Geoscience and Remote Sensing, vol. 58, no. 1, pp. 238-250, Jan. 2020. doi: 10.1109/TGRS.2019.2936108
Control of pre-existing crustal architecture on Cenozoic formation of the Pamir
Authors: Sobel Edward , Rembe Johannes , Kley Jonas , Zhou Renjie , Terbishalieva Baiansuluu , Chen Jie
Published: March 2020

The Cenozoic Pamir comprises the western equivalent of the Tibetan plateau, offset to the north by ca. 300 km. A significant geodynamic question is what controls the lateral extent of the Pamir. Here we suggest that the width of the Pamir is controlled by east-west variations in the rheology of blocks farther to the north. In particular, the rigid, Precambrian-cored Tarim block, directly north of Tibet, apparently does not extend farther west. Indirect evidence for this crustal structure is derived from the late Paleozoic - early Mesozoic evolution of the northern and external Pamir. The northern part of the Western Kunlun comprises Proterozoic Tarim basement; such rocks are unknown on the northern margin of the Pamir. In the late Ordovician or Silurian, the Kudi suture formed, representing the consumption of the Proto-Tethys and the collision of Tarim with the southern part of the Western Kunlun terrain. Although the Western Kunlun has been considered to be the lateral equivalent of the North Pamir, the Kudi suture does not appear to be preserved in the Pamir. In contrast, the North Pamir preserves remnants of a broad Carboniferous ocean which are not recognized in the Western Kunlun. The northern margin of this ocean is unclear; it may have merged with the Turkestan ocean, on the southern margin of the Tian Shan. There are no documented basement units directly north of the Pamir; the basement Garm block lies at the northwest corner of the Pamir and may represent a fragment of Tarim which we suggest must have been rifted away by the Ordovician. The North Pamir Carboniferous deep marine units are unconformably overlain by upper Carboniferous and lower Permian shallow marine units at the eastern and western ends of the North Pamir, suggesting a contractile episode; the contact appears to be conformable in the central part. The lower Permian is overlain by an uppermost Permian - Triassic back-arc basin or rift, which stretches ca. 500 km east-west. There is no evidence that this basin extended into the Western Kunlun. Therefore, the location of the Cenozoic Pamir corresponds to the extent of both Carboniferous oceanic crust and Permo-Triassic extended or oceanic crust. We suggest that the differences between the Western Kunlun Shan and the North Pamir reflect the presence and absence, respectively, of the rigid Tarim block to the north. Although it has been suggested that the geometry of the Pamir reflects the geometry of a promontory at the northwest corner of the Indian indentor; this seems highly improbable given the pre-Cenozoic history. Rather, we suggest that differences in the evolution of the Pamir and Tibet are first-order consequences of the different rheologies of the northern crustal backstops of these two regions.
Drivers of stable water isotope variability in the cold and warm sector of extratropical cyclones from two case studies in the Southern Ocean
Authors: Thurnherr Iris , Aemisegger Franziska , Jansing Lukas , Hartmuth Katharina , Gehring Josué , Pfahl Stephan , Böttcher Maxi , Berne Alexis , Wernli Heini
Published: March 2020

Dynamical processes in the atmosphere strongly influence the large temporal and spatial variability of the atmospheric branch of the water cycle. For instance, the advection of air masses by synoptic-scale weather systems induces air-sea moisture fluxes such as evaporation, precipitation and dew deposition. It is important to better investigate and quantify this linkage between dynamical phenomena and details of the atmospheric water cycle. In addition, one of the big challenges in monitoring the atmospheric water cycle is the measurement of turbulent moisture fluxes over the ocean. Stable water isotopes (SWIs) serve as a tool to trace atmospheric processes which shape the atmospheric water cycle and, thus, provide important insights into moist processes associated with weather systems, in particular air-sea fluxes.

In this study, we investigate the impact of air-sea moisture fluxes on the variability of SWI signals in the marine boundary layer. Measurements of the second-order isotope variable deuterium excess in the marine boundary layer of the Southern Ocean show positive/negative anomalies in the cold/warm sector, respectively, of extra-tropical cyclone due to opposing moisture fluxes and non-equilibrium fractionation processes in the two sectors. The drivers of these contrasting SWI signals are analysed using the isotope-enabled Consortium for Small-Scale Modelling model for two case studies. The simulated isotope signals during the case studies show excellent agreement with ship-based isotope measurements from the Southern Ocean performed during the Antarctic Circumnavigation expedition in January and February 2017.

The main driver of SWI variability in the cold sector is enhanced ocean evaporation which substantially modifies the advected SWI signal from the Antarctic continent during a cold air outbreak. In the warm sector, dew deposition on the ocean surface and cloud formation are mainly driving the observed negative deuterium excess anomaly, which can be conserved and advected over several 100 km in the warm sector of an extratropical cyclone.

The results of this study illustrate the strong dependence of the isotopic composition of water vapour in the marine boundary layer on the predominant atmospheric large-scale flow situation. In particular in the storm track regions, the variability of SWIs in marine boundary layer water vapour is largely shaped by the sign and strength of air-sea fluxes induced by the meridional transport of air masses.