bluuebunny/crossref_metadata_2025 huggingface dataset:
Maturity assessment of solid bitumen in the Sinian carbonate reservoirs of the eastern and central Sichuan Basin, China: insights from FTIR and Raman spectroscopy analyses
Authors: Chen Jiaxu , Guo xiaowen
Published: March 2022

Maturity assessment of solid bitumen is significant for the construction of the thermal evolution history of Sinian carbonate reservoirs in the eastern and central Sichuan Basin because of the absence of vitrinite. Occurrence characteristics of solid bitumen in the Sichuan Basin were investigated by petrography observation. Based on Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy analyses of solid bitumen, the thermal maturity of solid bitumen in the Sinian reservoir was evaluated, and the thermal history of the Sinian reservoirs in the eastern and central Sichuan Basin was further reconstructed. The results show that solid bitumen occurred within intercrystalline pores, intercrystalline dissolution pores, karst caves, fractures, and stylolites in the eastern and central Sichuan Basin. The FTIR spectrums of solid bitumen are characterized by depleted aliphatic carbon and C=O group, and enrichment of aromatic carbon. The FTIR spectrums of solid bitumen indicate that the thermal maturity of solid bitumen in the Sichuan Basin exceeds at least 1.3%. The calculated Ro of solid bitumen in the eastern Sichuan Basin ranges from 3.8 to 4.09%, that of solid bitumen in the central Sichuan Basin ranges from 3.51 to 3.77%, and that of bitumen inclusions in the central Sichuan Basin varies from 3.54 to 3.64% inferred from Raman spectroscopy analysis. The thermal evolution history of Sinian reservoirs in the eastern and central Sichuan Basin can be divided into two heating–cooling stages. At the end of the second heating stage, that is, the Late Cretaceous, the Sinian reservoir reached the highest temperature of 250 °C in the eastern Sichuan Basin and 225 °C in the central Sichuan Basin.
Improving Local Maxima-based Individual Tree Detection using statistically modelled Forest Structure Information
Authors: Schaller Christoph , Ginzler Christian , van Loon Emiel , Moos Christine , Dorren Luuk
Published: March 2022

Laser scanning-based tree detection has been used for many years to complement sample data of forest inventories. Local Maxima (LM) detection methods are suitable for individual tree detection in the forest canopy and allow for detection over large areas due to their computational efficiency. However, the performance of LM methods depends on factors such as the resolution of the input data (point density of aerial laser scanning (ALS) and spatial resolution of the derived rasters), the pre-processing of the input data as well as the structure and species of the detected forest. The main objective of our study was to evaluate to what extent LM tree detection can be improved by considering prior knowledge about forest structure using statistical modelling. To achieve this goal, we developed a statistical model for selecting between 10 different crown height model (CHM) pre-processing methods based on forest structure variables derived from remote sensing data. We fitted linear regression models predicting the error between the number of detected trees and the field inventoried number of the trees reaching the canopy in the sample plot. The model used dominant canopy height, the degree of coverage overall and for different forest layers derived from the CHM, the dominant leaf type derived from Sentinel-2 data, and terrain characteristics as explanatory variables. The model performance was evaluated by assessing tree detection errors using all national forest inventory plots in Switzerland using 10-fold cross-validation. The results showed a reduction of the RMSE to 91 stems per ha (respectively 1.3 when normalized by the inventoried stem number) using the model-based pre-processed CHM for detection compared to 205 stems per ha (normalized = 4) when detecting trees using an unprocessed CHM (number of used inventory plots n=5254). Excluding inventory plots with an ALS point density of less than 15 points per square meter (n=3797) improved the RMSE to 89 stems per ha (normalized = 1.25).The RMSE further improves to 85 stems per ha (normalized = 1.2) by additionally excluding plots with more than 6 years between ALS acquisition and inventory (n=2676). Although the results show a clear reduction of the detection error by our model, they also indicate potential for further refinements. Especially the integration of high-quality ALS data (becoming available for the entire area of Switzerland until 2024), detailed tree species data, and additional, more recent inventory data are recommended. In the future, a combination of our method with point cloud-based approaches will probably be able to further reduce detection errors at national scale.
Developing a global database of contemporary sediment yield observations
Authors: Tan Florence , Borrelli Pasquale , Verstraeten Gert , Tsyplenkov Anatoly , Campforts Benjamin , Golosov Valentin , Lehner Bernhard , Poesen Jean , Vanmaercke Matthias
Published: March 2022

For many decades, sediment yield (SY) observations have been collected around the world to analyze, monitor, and better understand the state and dynamics of various Earth system processes. These records are highly relevant for a wide variety of research applications, yet they remain poorly accessible, especially for large-scale studies. A main reason for this is the fact that many of these measurements are collected on an isolated basis, leading to inconsistencies across data sets. SY observations also suffer from large uncertainties in data quality: key factors such as location accuracy, sampling method and frequency, measuring period, and others vary greatly but are not systematically reported.

To address these shortcomings and provide a standardized global reference for SY data, we are developing an extensive, coherent and georeferenced global database of contemporary SY observations. Through an extensive review of (grey) literature and contacts with numerous research groups, we already compiled SY observations for >8,000 catchments worldwide (comprising a total of >80,000 catchment years of observations). These observations are either derived from gauging station measurements or reservoir sedimentation rates. We assess the reliability of SY records and provide data quality indices based on available information such as measuring location, reported catchment area, sampling method and frequency, and measuring period. We further link the SY observations to the HydroSHEDS global river network, making them readily accessible and consistent with a wide array of hydro-environmental catchment variables also connected to the HydroSHEDS network. 

This new global SY database creates untouched opportunities for large-scale model development and statistical analyses of sediment-related factors and processes, such as soil erosion, sediment budgets, land cover and land use change impacts, or hydrological and sediment connectivity. Here we present a first overview of the data collected so far, its spatial patterns and its research potential. 
Operational monitoring of our hazardous planet with Sentinel-1
Authors: Wright Tim , Hooper Andy , Lazecky Milan , Maghsoudi Yasser , Spaans Karsten , Ingleby Tom
Published: March 2022

The European Commission’s Sentinel-1 constellation, operated by ESA, has been a game changer for operational monitoring of our hazardous planet. When fully operational, the Sentinel-1 mission is a two-satellite constellation; currently consisting of Sentinel-1A (launched in 2014) and Sentinel-1B (launched in 2016), the mission provides at least one SAR image for the whole land surface every 12 days, with both ascending and descending data acquired in tectonic/volcanic areas globally every 12 days, and images acquired in both geometries every 6 days over all of Europe. The narrow orbital tube, consistent imaging geometry, and long time series are optimised for ground deformation measurements with InSAR. Sentinel-1C and -1D have been built and will replace the existing satellites in due course. Perhaps the most important game changer has been the Copernicus data policy, which mandates fully free and open distribution of Sentinel-1 products for all applications, whether they are for research or commercial purposes. Sentinel-1 InSAR data has quickly become the primary data set for monitoring ground movement in our hazardous planet. Several research organisations/collaborations now process enormous quantities of Sentinel-1 data to produce deformation products that are made freely available through organisations like COMET in the UK, EPOS and the new European Ground Motion Service in Europe, and the Alaska SAR Facility in the US. Commercial providers are processing data at scales ranging from individual bridges/dams through to whole countries. In this presentation we will focus on Sentinel-1 results produced academically by COMET and commercially by SatSense Ltd. COMET now responds routinely to all continental earthquakes bigger than M5.5 and provides interactive tools and machine-learning-based alerting for global volcanoes. COMET is combining Sentinel-1 InSAR with GNSS to map tectonic strain at high spatial resolution on a continental scale, in areas including Anatolia, Tibet and Iran, and using the results to improve our understanding of seismic hazard. SatSense have demonstrated the value of Sentinel-1 InSAR for applications including dam monitoring, water pipe failures and railway infrastructure. The SatSense processing approach allows InSAR ground movement data to be kept continuously up to date for entire countries. We conclude the presentation by discussing prospects for the future of InSAR beyond Sentinel-1.
Ground subsidence and fault reactivation during in-situ coal conversion assessed by numerical simulations
Authors: Hedayatzadeh Mansour , Sarhosis Vasilis , Gorka Torsten , Hámor-Vidó Mária , Kalmár István
Published: March 2022

One unconventional coal extraction method is in-situ coal conversion. In this process, the coal is gasified in an underground reactor. A crucial issue that should be considered in this approach is the assessment of short and long-term environmental hazards and risks to human health and the environment resulting from potential surface subsidence and fault activation in the presence of complex geological conditions. This research aimed to assess potential environmental impacts associated with a commercial-scale application of in-situ coal conversion in a high coal production area in the Maza-Varalja region in Hungary. The Maza-Varalja region is an environmentally protected forested area. In this research, the numerical modeling of surface subsidence and fault activation was implemented using the finite-volume numerical modeling software FLAC3D. A predictive three-dimensional geomechanical model has been developed using site-specific geological data. The material model is Mohr-Coulomb elastic-plastic. Zero thickness interfaces were employed to address the fault behavior with friction and cohesive characteristics. The in-situ stress was determined by geostatic loading and a horizontal stress factor. The boundary conditions were zero-displacement and positioned sufficiently far from the coal seams to not artificially influence the stress field. The initialized zone stresses were considered using the density of the zones above them and gravity. The horizontal to vertical stresses ratio was determined to be one. A series of sensitivity studies were conducted to address the importance of geologic parameters that have an impact on surface subsidence, fault activation, and pollutant migration to the surface. In order to achieve this, seven variables, including the unit weight, Young’s modulus, Poisson’s ratio, friction angle, cohesion, fault friction, and excavation sequence, were considered. Sixty-six simulations were undertaken and analyzed. The simulation results demonstrate that surface subsidence is affected by the average Young’s modulus of the geological strata and the fault activation to the friction angle of the faults. Also, shallower seams are more likely to produce surface subsidence, while as excavation depth increases, surface subsidence decreases. The model's results have been used to develop an Environmental Hazard and Risk Management toolkit (Tranter et al., 2022) for planning and decision-making processes during in-situ coal conversion to ensure that environmental risks and mitigation actions are clearly quantified and outcomes forecasted. 
Heavy summer precipitation events in the Sichuan basin and their connection to meso-scale convective systems and Tibetan Plateau vortices
Authors: Curio Julia , Dugoul Anna , Kukulies Julia , Chen Deliang
Published: March 2022

Heavy summer precipitation events in the Sichuan basin, located at the eastern edge of the Tibetan Plateau (TP), can lead to disastrous flooding and landslides amplified by the complex terrain. Those events pose a threat to people’s lives and livelihood as well as infrastructure in this densely populated part of China.

Mesoscale convective systems (MCSs) were identified as the source of some heavy rainfall events in the downstream regions of the TP including the Sichuan basin. Some case studies argue that Tibetan Plateau vortices (TPV) play a crucial role in the development of MCSs and extreme rainfall events in the Sichuan basin.

MCSs are recognized as cloud clusters that produce heavy rainfall over large areas, while TPVs refer to frequently occurring meso-scale vortices that are initiated over the TP and mainly travel eastwards steered by the large-scale circulation. Around 20% of TPVs can move off the TP and affect the mainland of China, especially the regions close to the TP like the Sichuan basin and the upper reaches of the Yangtze and Yellow Rivers.

In this study, we identify the most extreme summer precipitation events in the Sichuan basin for the period 2000-2018 using daily accumulated rainfall observations from meteorological stations operated by the China Meteorological Administration (CMA). We analyse how many of those events are attributable to MCSs and if so whether there is a TPV in the vicinity affecting the MCS initiation and development. We make use of databases of MCSs and TPVs in the region of interest for which MCSs and TPVs have been identified using objective tracking algorithms.

Linking extreme precipitation events in this region to the occurrence and moving-off of TPVs may help to improve forecasts of extreme precipitation and subsequent flooding.
A country scale assessment of the heat hazard-risk in the urban areas of Romania
Authors: Cheval Sorin , Dumitrescu Alexandru , Irașoc Adrian , Paraschiv Monica-Gabriela , Amihăesei Vlad , Ghent Darren
Published: March 2022

Heat-related hazards pose major risks to our cities and the projected climate changes indicate substantial increases in impacts, and a better understanding of the interactions between environmental changes and human health are particularly critical for improving the living quality in urban areas in the climate change context. The considerable progress of monitoring, modelling, and analysing methods has addressed the increasing demand for enhanced accuracy, finer resolution, and better accessibility of climate products and services, including the specific needs of the built-up areas.

This study informs the present Heat Hazard-Risk (HHR) over the 262 cities of Romania using a risk matrix approach that aggregates the hazard triggered by high temperatures (i.e. Land Surface Temperature), and elements of vulnerability associated with the structure (i.e. Local Climate Zones - LCZ), and population density (i.e. number of inhabitants per 100 m2 in each urban area).

The MODIS LST_cci products used in this study are customised TERRA_MODIS_L3C and AQUA_MODIS_L3C daily day/night 0.01° resolution data on an equal angle latitude/longitude data over Romania produced within the project LST_cci+ (CCI Land Surface Temperature, 2020), and covering the period 2000-2018. The LCZ values were extracted from a European database characterizing the urbanised landscapes derived within the World Urban Database and Access Portal Tools (WUDAPT) project. The population density was retrieved from the Joint Research Centre (JRC) database.

Generally, the HHR is higher in the central parts of the cities, but industrial and residential areas contribute to high-risk values towards the marginal perimeters too. The size and the industrial profile of a city impact the extent of the heat risk. For example, the biggest cities in the southern areas hold the most extended areas at risk at the country level. The land cover is a significant factor that controls the thermal hazard risk in the urban areas of Romania: the highest HHR values correspond to the discontinuous urban fabric, industrial and commercial units, and construction sites, while the lowest values stand for the urban forest, and water bodies.

This study has received funding from the European Space Agency (ESA) within the framework of the Land Surface Temperature project under the Climate Change Initiative (LST_cci), contract number 4000123553/18/I-NB.
Climatic drivers explain the interannual variability of the globalburned area
Authors: Gincheva Andrina , Jerez Sonia , Pausas Juli G. , Bedía Joaquín , Vicente-Serrano Sergio M , Provenzale Antonello , Chuvieco Emilio , Abatzoglou John , Turco Marco
Published: March 2022

Understanding the response of fire to climate variations is essential to adapt fire management systems under climate change. Although several studies have analysed the drivers of the average spatial variability of fire, the assessment of the temporal variability of fire in response to climate across the globe has proved challenging, largely due to complexity of the processes involved, the limitation of observation data and the compound effect of the multiple drivers, which usually cause non-linear effects.

In this study, we analyse how much of the interannual variability in observed burned area (BA) is linked with temporal variations in climate at global scale. To solve this question, we use the burned area data of the FireCCI51. product for the period 2001-2019 at the global scale, and different climate metrics that are directly related to drought occurrence, including indices like the Fire Weather Index (FWI), the Standardized Precipitation Evapotranspiration Index (SPEI), and the Standardized Precipitation Index (SPI). Our study shows complex spatial patterns in the relationship between climate drivers and BA variability, highlighting where variations in FWI, SPI, SPEI or their interaction explain BA variability. While in some areas the interannual variability of burned area does not show a statistically significant influence of climate variability, over a substantial portion of the global burnable area (~60%) the BA variability can be explained by interannual variability of climate drivers. Globally, climate variability accounts for roughly two thirds (64%) of the observed temporal BA variability.
Evaluation of hourly precipitation in convection permitting models using scaling: are they better than parameterized models?
Authors: Lenderink Geert , de Vries Hylke , Brisson Erwan , Berthou Segolene , Kendon Elizabeth
Published: March 2022

Convection permitting climate models (CPMs) are nowadays increasingly used in climate change assessment. These models have shown to have vastly improved convective rainfall statistics compared to parameterized regional climate models (RCMs). Here, we analyse hourly rainfall extremes within the framework of scaling, investigating the dependencies on temperature, dew point temperature as measure of absolute humidity, and dew point depression as a measure of relative humidity. We compared  7 RCM simulations and 5 CPM simulations to observations from The Netherlands (a moderate moist climate) and Southern France (a warm and dryer climate). Although present-day scaling is no simple predictor of climate change, reproducing observed dependencies on the various temperature and humidity measures provides evidence that these models are  trustworthy in a climate change setting. We find that RCMs display a large spread in outcomes, in particular in their  dependency on relative humidity and usually strongly biased towards too strong suppression of extremes in low relative humidity conditions.  CPMs have (unsurprisingly) much better overall rainfall statistics, show much less inter-model spread, and temperature and humidity dependencies more consistent with the observations. Yet, most CPMs have a climatology biased towards too low relative humidity, affecting also the rain statistics, and underestimate the frequency of rain, in particular for conditions with high relative humidity. Our results suggests that, while CPMs are clearly better in convective rain processes, improvement are needed in weakly surface forced convection as well as the overall climatology/water balance of the models. 
Sharing the burden of carbon dioxide removal 
Authors: Fyson Claire , Ganti Gaurav , Schleussner Carl-Friedrich
Published: March 2022

The exercise of translating a global carbon budget into other policy-relevant metrics, for instance, global and regional emission pathways over time is, unavoidably laden with value judgements, raising questions around inter- and intra-generational equity. As net zero targets are increasingly adopted by countries around the world, clarifying their adequacy from a perspective of fairness is essential. Given significant delays in reducing emissions globally, achieving net zero emissions will require the deployment of carbon dioxide removal (CDR) technologies. Recent studies have started to apply equity-based indicators to assess how emission removal obligations could be shared between countries contrasting the resulting distribution of CDR deployment with cost-optimal distributions produced by Integrated Assessment Models. The choice of framework used to share CDR between countries in Paris Agreement compatible pathways - whether based on principles of equity or a least-cost approach - has implications for how these pathways are used to inform CDR governance and policy. This includes how they are used to evaluate targets for achieving net zero (and even net negative) emissions and the CDR assumptions that underlie them, as well as to assess which CDR technologies should be developed and how they should be financed. 

Here we will explore the principles of equity and justice that can be considered relevant to CDR deployment in the context of the Paris Agreement. Drawing examples from recent analysis (Fyson et al. 2020, Lee et al. 2021), we will look at how such principles could be applied quantitatively to evaluate national targets and policies. In doing so we will highlight the importance of applying an equity and justice lens when developing Paris Agreement compatible emission reduction and removal strategies.

References

Fyson, C. L., Baur, S., Gidden, M. & Schleussner, C. F. Fair-share carbon dioxide removal increases major emitter responsibility. Nat. Clim. Chang. 10, 836–841 (2020).

Lee, K., Fyson, C. & Schleussner, C. Fair distributions of carbon dioxide removal obligations and implications for effective national net-zero targets. Environ. Res. Lett. 16, (2021).
An innovative temperature monitoring approach to ensure the sustainable use of shallow geothermal energy on quarter scale
Authors: Hastreiter Nele , Vienken Thomas
Published: March 2022

Increasing the share of renewables in the heating sector is crucial to reduce CO2-emissions. Using the shallow geological subsurface for heating and cooling is part of the solution. Especially the use of shallow geothermal energy for heating is widely applicable. An intensive but at the same time sustainable shallow geothermal use is essential to avoid interactions between geothermal users with a resulting decrease in system efficiency or competing use with other subsurface usages, e.g. groundwater provision. The intensive thermal use of the shallow subsurface is generally controlled by monitoring of subsurface or groundwater temperatures. Induced changes of subsurface or groundwater temperatures are required to not exceed specific thresholds over time. However, the urban subsurface is exposed to different sources of temperature impacts which need to be considered during the long term subsurface or groundwater temperature monitoring to determine absolute changes. This is especially true for new urban quarters. Elevated groundwater temperatures in densely populated areas in comparison to the rural surroundings, often referred to as groundwater urban heat islands, have been observed and investigated over decades. However, only little information is available about the formation of heat islands over time and yet, its effects are hardly considered in groundwater temperature monitoring practice. To overcome this lack of knowledge, this study follows an innovative approach by coupling simulated elevated groundwater temperatures for a densely settled quarter with empiric groundwater temperature data. Therefore, heat losses from buildings and their contribution to the formation of groundwater urban heat islands over time are analysed for a refurbished quarter with a building stock of 150 houses and intensive use of shallow geothermal energy in Cologne, Germany.  To simulate heat losses from buildings, different scenario analyses with houses of varying insulation standards are performed using a building physics software. Obtained results were then implemented into a groundwater flow model to evaluate the impact on underground temperatures over time and compared with measured data of the same area. Simulation results reveal that the geothermal heating activities impact the groundwater temperatures more than the monitoring data suggests.
Integrated hydrological modelling for decision support to improve field and catchment scale water management in agriculture
Authors: Mustafa Syed Md Touhidul , Autio Anna , Haghighi Ali Torabi , Marttila Hannu , Avellan Tamara , Schilling Oliver S. , Brunner Philip , Scholz Miklas , Klöve Björn
Published: March 2022

Particularly in the Nordic region, water excess and shortage (drought) are becoming more frequent phenomena that challenge the development of agriculture and crop production. Identification of appropriate water management strategies is essential (i) to ensure sustainable water resources management for crop production and the functioning of healthy ecosystems; and (ii) to improve resilience to hydrological extremes. Integrated hydrological models offer that potential through understanding and forecasting of hydrological systems under anthropogenic and climatic influences, and providing information for improved decision-making. This study aims to develop a decision support instrument based on integrated hydrological modelling to identify appropriate management solutions and improve field- and catchment-scale water management in Nordic agriculture. The study area is Tyrnävä catchment, located in the northern part of Finland near Oulu city. Initially, the available hydro-climatological and hydrogeological data of the Tyrnävä catchment are characterized in detail. Then the hydrogeological parameters of the model are identified based on existing hydrogeological, climatic and remotely sensed data and their spatial, temporal and vertical variability. Next, a regional integrated surface-subsurface hydrological model is set up using HydroGeosphere. After successful calibration and validation using observed groundwater level, river discharge and soil moisture data, the model will be used in implementing and evaluating different management strategies (e.g., different irrigation options during droughts and controlled drainage management) for the future and their influence on the surface and groundwater systems. Uncertainty arising from different sources will be quantified using the Integrated Bayesian Multi-model Uncertainty Estimation Framework with the support of a supercomputer to improve the reliability and accuracy of the decision support instrument. Additionally, stakeholders’ involvement through local workshops is ensured throughout the modelling study, from the beginning to obtain reliable and useful decision support. Finally, based on these results, informed decisions regarding the appropriate water management can be made, which is important for sustainable water resources management for crop production and the functioning of healthy ecosystems particularly in Nordic agriculture.
Inferring groundwater response time at regional scale by following a spectral approach
Authors: Di Dato Mariaines , Houben Timo , Attinger Sabine
Published: March 2022

Groundwater is the main component of river discharge during low-flow periods. The aquifer response to recharge typically depends on the catchment hydro-geological characteristics, such as the hydraulic conductivity, the storage coefficient and the aquifer dimensions. Moreover, such a response time is key to buffer drought propagation during dry periods. As a consequence, it is of paramount importance to evaluate how fast an aquifer will react to an external perturbation. Here, we apply a spectral approach to evaluate the aquifer response time. At the regional scale, the aquifer behaves as a low-pass filter, which modifies the input signal (e.g., the recharge) in the output signal (e.g., the baseflow) according to its properties. For instance, the groundwater response will be faster when the aquifer transmissivity is high or the storage is low. We tested our method across a wide range of German catchments using stream flow datasets. Spectral analysis across catchments of different sizes can provide insight into the spatial aggregation of groundwater response, thereby indicating the scaling rule in large heterogeneous catchments. This approach can help to evaluate the response time in humid regions, which are characterized by frequent interruptions of recession periods. Moreover, response time can serve to quantify the effect of possible external perturbations (climate, irrigation or land management changes) on aquifer resilience.
An unmanned aircraft system for (offshore) wind energy research
Authors: Weber Ines , Platis Andreas , zum Berge Kjell , Schön Martin , Boventer Jakob , Djath Bughsin , Schulz-Stellenfleth Johannes , Bange Jens
Published: March 2022

The Multipurpose Airborne Sensor Carrier (MASC) is a fixed-wing unmanned aircraft system (UAS) that has been continuously developed and used for in-situ, high-resolution flight measurements of atmospheric variables such as wind, temperature, humidity as well as trace gas and particle concentrations by the Environmental Physics group at University of Tübingen. The most recent innovation in the MASC-series is the MASC-V type vertical takeoff and landing UAS. It has been designed in cooperation with ElevonX d.o.o.. Compared to its predecessor, MASC-3, it can automatically takeoff and land on small patches of land while carrying an identical atmospheric measurement payload. This capability, complemented by an enhanced safety and operational concept, allows for deployment in offshore applications. Particularily, MASC-V has demonstrated safe operation beyond visual line of sight (BVLOS) from the remote safety pilot in offshore applications within the EUs new legal framework introduced in 2020.

Before its first offshore mission, MASC-V underwent a full system validation against a meteorological tower at the German Weather Service (DWD) Observatory site at Falkenberg, Germany. Offshore measurements were conducted from the German offshore island Heligoland at the Testfield for Maritime Technologies in cooperation with the Fraunhofer Institute for Applied Material Science in September 2021. The goal of the Heligoland campaign was to validate the remote sensing of sea surface wind measurements by Synthetic Aperture Radar (SAR) satellites of the Sentinel-1 formation at low flight altitudes (20 m - 30 m). SAR satellites can deliver detailed wind data over large areas such as the German Bight including for example wind farm wake effects. Direct validation of these results is difficult with other in-situ techniques. Buoys and measurement towers or platforms can provide stationary data. Aerial measurements with manned aircraft are only possible at higher altitudes. The new UAS data provide the first aerial in-situ SAR validation measurement at low altitude. Additionally, we have demonstrated the capabilities of VTOL fixed-wing UAS for vertical profiling as well as to operate tens of kilometers away from ground personell over open water.
Why does the leaf of Japanese Cypress in temperate region experience transient leaf reddening under winter excessive light stress
Authors: Chen Siyu , Kosugi Yoshiko , Jiao Linjie , Nakaji Tatsuro , Noda Hibiki , Hikosaka Kouki , Nasahara Kenlo
Published: March 2022

The leaves of evergreen coniferous species in the temperate region sometimes were observed to change from green to red before or during winter and persist until next spring. This phenomenon is also called 'winter leaf reddening', which might be a photoprotection strategy for plant leaves to deal with excess light stress during winter and early spring. In gymnosperms, the xanthophyll cycle (VAZ cycle) and accumulation of red pigment (e. g. rhodoxanthin) can prevent excess light damage to the photosynthetic apparatus. However, the joint role of these two processes in corresponding with canopy photosynthesis under winter excess light stress has not been further studied. This study aimed to clarify: (1) whether the low temperature is the dominant factor affecting the winter leaf reddening phenomenon and ascertain the air temperature conditions when this phenomenon occurs; (2) whether rhodoxanthin and the VAZ cycle play a collaborating role in regulating low light-use efficiency (LUE) under low air temperature conditions during the winter season; (3) the difference between two leaf redness indicators obtained from phenological method and remote sensing method.

Canopy leaf redness indicators were obtained in two ways. The automated system with a digital camera was used to monitor the canopy phenological changes. The RGB channels of image data were extracted to calculate the Red-Green vegetation index (RGVI). Red index (RI) is obtained by spectral reflectance analysis to track rhodoxanthin variation patterns. The photochemical reflectance index (PRI) was utilized as a tool to reflect the VAZ cycle. The canopy CO2 flux was measured with the eddy covariance method, which can be used to calculate LUE. Micrometeorological data were also monitored.

Our results suggest that low air temperatures in winter play a domain role in the occurrence of winter leaf reddening. The onset of winter leaf reddening was accompanied by a decrease in LUE and PRI and a corresponding increase in RGVI. This suggests that the accumulation of rhodopsin and the VAZ cycle may play a collaborative role in regulating LUE under the combined effect of chilling temperatures and high solar radiation conditions. There were temporal differences in the peak occurrence of RI and RGVI, but the change characteristics were largely consistent, which may indicate that RI can more sensitively monitor the timing of red appearance in the vegetation canopy.

Keywords: winter leaf reddening, Japanese cypress, photochemical reflectance index (PRI), Red index (RI), Red-Green vegetation index (RGVI), phenological analysis, digital camera, light-use efficiency (LUE)
Uncertainty in estimating the observed relationship between hourly precipitation extremes and dewpoint temperature
Authors: Ali Haider , Pritchard David , Fowler Hayley , Lewis Elizabeth
Published: March 2022

Short-duration (hourly) precipitation extremes have intensified in the past and they are projected to increase more under the warming climate. The Clausius-Clapeyron (CC) relationship can be used to understand the sensitivity (scaling) of precipitation extremes with warming. According to the CC relationship, hourly precipitation extremes intensify at around a 7% (CC rate) per degree rise in temperature. However, the observed scaling rates deviate from the CC rate which can be due to multiple thermodynamic and dynamic factors which have been discussed in the recent scaling studies. Moreover, the choice of data and scaling methods may also lead to uncertainty in scaling rates. In this study, by using observed hourly precipitation and daily dewpoint temperature over the USA, we show that robust quality controlled precipitation data show differences in scaling. We also obtained higher scaling rates for the higher measurement precision data (0.25mm and 2.5mm). We further show the uncertainty in scaling rates using different four scaling methods. Our results highlight the need of using extensive quality controlled and finer precision observations for estimating accurate scaling rates.

 
Estimation of landslide risk at national scale by means of environmental indicators
Authors: Caleca Francesco , Segoni Samuele
Published: March 2022

The purpose of this work was the definition of a new set of environmental indicators for a fast estimation of landslide risk over very wide areas. The proposed methodology was performed in GIS environment using Italy (301.340 km2) as test case since it is a country characterized by a very high exposure to hydrogeological disasters and where landslides are very common.

The proposed indicators aim to characterize landslide risk by quantifying how much urban expansion interferes with geomorphological processes; to this end a landslide susceptibility map and a soil sealing/land consumption map were combined to derive a spatially distributed indicator over the whole Italian country (namely, Landslide Risk Index - LRI). LRI emphasizes how much anthropic elements are exposed to landslide processes, and it is a basic element which can be aggregated over larger spatial units to characterize them respect to risk. To this aim, LRI was aggregated at the municipal scale in order to define two more indexes named Average Landslide Risk (ALR) and Total Landslide Risk (TLR).

ALR was defined by the mean value of LRI for each municipality: it represents how hazardous is the area of the territory where the exposed elements have been located. TLR was defined as the sum of susceptibility values of all cells with land consumption within each municipality: it expresses how much the urbanization of a municipality involves areas which can be affected by landslides.

The highest values of ALR are located in small municipalities renowned as international holiday destinations located by the sea in rocky coasts; on the contrary, highest values of TLR are in large and densely urbanized municipalities and where large portions of the territory urbanized are located in hazardous areas. The obtained results are supported by evidence collected from other national databases of landslide hazard and risk.

Both indexes showed to be useful to evaluate if local administrations have been prudent in planning urban development or if they ignored the geomorphological hazards threatening its territory. The proposed indexes are simple to understand and they can be adapted to various contexts and at various scales (e.g provinces, districts or basins) and updated with very low efforts. Obviously, they represent an oversimplification of the complexity of landslide risk and they cannot substitute a detail quantitative risk assessment, nevertheless a thorough national-scale risk assessment is not yet feasible in Italy and this is the first time that a set of landslide risk indicators have been defined in Italy at national scale combining landslide susceptibility and land consumption maps allowing to gain preliminary insights about the landslide risk produced by the interaction between hillslope dynamics and urban expansion.
Downscaling to high-resolution and correcting air temperature from the ERA5-Land over Ethiopia
Authors: Wakjira Mosisa Tujuba , Peleg Nadav , Molnar Peter
Published: March 2022

Climate information from in-situ observation networks can be used to significantly improve the accuracy of gridded climate datasets, even in data-scarce regions. We applied a bias correction and spatial disaggregation method on daily maximum and minimum ERA5-Land (ERA5L) 2-m air temperature dataset covering Ethiopia. Due to large gaps in the observed temperature data, the bias correction is based on the statistics rather than the complete time series. First, long-term daily, monthly and annual temperature statistics (mean and variance) were summarized for the time series obtained from 155 stations covering the period 1981-2010. Second, the temperature statistics were interpolated onto a 0.05° x 0.05° grid using an inverse non-Euclidean distance weighting approach. This method accounts for the effects of elevation, thus enabling downscaling of the temperature to a higher spatial resolution. Next, the ERA5L maximum and minimum temperature were bias-corrected using quantile mapping assuming a Gaussian distribution transfer function. The quantile mapping was performed at daily, monthly and annual time steps to reproduce the climatology, seasonality, and interannual variability of the data. The performance of the bias correction was evaluated using the leave-out-one cross-validation method. The cross-validation shows that the bias-corrected maximum (minimum) daily temperature has an improved mean absolute error value of 68% (52%) in comparison to the original ERA5L reanalysis air temperature bias. The bias-corrected dataset is therefore suggested as an alternative for the ERA5L and can be used in a wide range of applications in Ethiopia.
Investigation of rock slope failure processes in the Southern Swiss Alps 
Authors: De Pedrini Alessandro , Ambrosi Christian , Scapozza Cristian , Manconi Andrea , Agliardi Federico
Published: March 2022

The evolution of rockslide processes towards failure events depends on the combination of geological and geomorphological properties, structural setting, and the glacial history of each site. The identification and analysis of the dominant factors affecting the spatial distribution and the temporal evolution of such massive phenomena are relevant not only for scientific purposes but also have large impacts on hazard assessments. Several large rockslide phenomena are located between five valleys north of Bellinzona, southern Swiss Alps, including the Riviera, Leventina and Blenio valleys in Canton Ticino, and the Calanca and Mesolcina valleys in Canton Grisons. The distribution of such phenomena is highly variable and appears to be higher along the eastern side of the Leventina Valley and the western side of the Blenio valley rather than in the rest of the region. Furthermore, the observed failure events range from 13.50 ka cal BP to 2002 CE, and many rockslides have not yet collapsed despite visible signs of surface deformation. The reasons for these differences in spatial and temporal distribution are yet unknown.  
Our research aims to define the influence and relationship of regional and local factors on the spatial and temporal rockslides distribution in this study area. We rely on an exceptional dataset including (i) detailed geological and geomorphological mapping of the area of study, (ii) a collection of historical data and scientific research on the activity of the large rock slope failures in Ticino and Grisons Cantons, (iii) detailed knowledge of the timing of deglaciation for several valleys of the Canton Ticino, (iv) a catalog of instabilities of the Canton of Ticino finalized in 2016, and (v) several results of current surface deformation activity constrained with satellite radar interferometry. Here we present the preliminary results of the activities performed to extend the rockslides catalog in the Calanca and Mesolcina valleys (Canto Grisons) obtained through the evaluation of stereo-photogrammetry datasets and evaluating the state of activity with satellite radar interferometry. Moreover, we will detail the approach used to set upslope stability modeling attempts at selected locations, combining techniques such as slope exposure dating, analysis of morphological parameters from digital elevation models, and analysis of structural data providing the dominant orientations of rock mass discontinuities.
Classification and prediction of days with extreme rainfall using random forest approach
Authors: Grazzini Federico , Grams Christian , Craig George
Published: March 2022

In a previous transfer project T1 of the SFB-Transregio “Waves to Weather” (W2W) a strategy was designed to classify precipitation extremes in Northern Italy and to provide additional information on the physical and dynamical drivers associated with it. Building on this, in collaboration with ARPAE-SIMC and ECMWF, we designed a new transfer project called TEX (Towards seamless prediction of EXtremes). The project has the final goal to expand and generalize this dynamical methodology to other regions and into the sub-seasonal forecast range (10-30 days). In this contribution, we present the first results concerning the validity of this method in the medium-range forecast. In particular, we show the accuracy of the random forest classification method, essentially based also on atmospheric upper-level predictors, in recognizing days with a high probability of extreme precipitation events compared to a forecast based only on precipitation outputs. These results, which are still referring to the test area of N-Italy, are preparatory for a further generalization to different areas and at a longer forecast horizon.
Microclimatological conditions along a land use gradient in the tropical Andes of South Ecuador
Authors: Trachte Katja , Pucha Cofrep Franz , Raffelsbauer Volker , Limberger Oliver , Fries Andreas , Carillo-Rojas Galo , Bendix Jörg
Published: March 2022

Knowledge about microclimatological conditions strongly contributes to our understanding of land surface – atmosphere interactions as drivers of the Earth’s surface energy budget. Particularly the radiative fluxes are major determinants providing energy for vital climate processes and are crucial for climate warming, water availability, primary productivity and ecosystem services. The partitioning into sensible and latent heat fluxes are highly dependent on the land coverage and represent feedback effects affecting the cycling of heat and water in the vegetation-atmosphere continuum. In the Reserva Biologica San Francisco (RBSF) on the eastern escarpment of the South Ecuadorian Andes on 2000m elevation above sea level (a.s.l.) two eddy-covariance measurement stations have been installed over natural rain forest and pasture ecosystem to observe atmospheric water and carbon fluxes. The aim is to assess net-ecosystem exchange (NEE) and evapotranspiration (ET) in order to estimate the impact of deforestation on the carbon sink function and the water availability. Additionally, microclimatological conditions in terms of e.g. radiative fluxes and soil conditions are supposed to further disentangle effects of the respective land surface properties on the environmental conditions. Over the last three years generally higher water fluxes could be observed during daytime over the forest ecosystem compared to pasture. Concerning NEE a clear carbon sink was revealed for both ecosystems indicated by a mean gross primary productivity (GPP) of 12.7 gC/m²day (forest) and 6.5 gC/m²day (pasture), while a mean ecosystem respiration (Reco) of 10.6 gC/m²day (forest) and 5.9 gC/m²day (pasture) was obtained. However, a mean NEE of 2.1 gC/m²day (forest) and 0.6 gC/m²day (pasture) clearly shows the stronger productivity of the forest ecosystem and thus, a higher carbon sink as a contribution to climate change mitigation.