bluuebunny/crossref_metadata_2025 huggingface dataset:
Enabling the mainstreaming of nature-based solutions into policy-making and governance: Holistic and systemic approach and coherence across policies to build a sustainable, circular and resilient planet and tackle societal challenges
Authors: Garcia Mateo Maria Carmen , Tillie Nico
Published: March 2022

Globally, there is clear evidence that unsustainable urbanisation and climate change are pressing challenges for our systems. Nature-based Solutions are starting to be considered as a mechanism to help underpin and tackle societal and global challenges such as biodiversity loss, ecosystem depletion, resource use or human and ecological well-being. Nevertheless, still disciplines are working separately and enabling the co-design of Nature-based Solutions to reach sustainable urban planning in cities is far to be considered for climate adaptation and climate neutrality in cities. Therefore, the study intends to overcome those research gaps mentioned. On the way to tackle those issues, the paper frames the necessity to align science, policy and society goals to reach a sustainable future and bring sectors together to ensure and help build an inclusive, healthy and a resilient world. The methodology is based on a systematic review process where we explore the state of the art on the matter. This paper intends to open the discussion of a holistic, systemic and comprehensive approach to mainstreaming Nature-based Solutions  and  presents a novel pathway for transdisciplinary climate and environmental planning action. A novel conceptualization; socio-ecological and environmental-economic framework for Nature-based Solutions action plan with defined key principles to enable the mainstreaming of nature-based solutions into policies and governance. The study recommends and proposes specific nature-based solutions strategies to underpin the lack of coherence that sometimes shows in some approaches when designing and planning cities, implementing policies for sustainable urban planning and design, facilitating ecosystem restoration and human well-being. To reach an environmentally, socially, economically, locally, ecologically and politically sustainable, circular and resilient Europe by 2030 to help deliver the global policy agendas and the European Green Deal and its strategies.
On the need for sub-daily data to study changes in extreme rainfall.
Authors: Argüeso Daniel , Di Luca Alejandro
Published: March 2022

Heavy rainfall is among the most impactful natural events. Our understanding of such events has improved significantly in the last decades, but large uncertainties remain around their recent and future response to a changing climate. At global scales, the frequency and intensity of daily extreme precipitation has increased, the hydrological cycle is becoming faster. However, the response at regional scales and shorter timescales is much more complex. The study of sub-daily or even sub-hourly data has been explored to some extent only, mostly due to the limited availability of data. When using high-resolution models to explore rainfall changes, it is possible to examine much higher frequencies, yet most studies focus on daily rainfall changes.

Here, we demonstrate inherent limitations of daily data to study present and future precipitation extremes. Limitations that are not purely a matter of refining our sampling, but do have a physical background because outstanding rainfall rates rarely occur over the course of a day. Our results show that fundamental aspects of rainfall changes are not described with daily data, and the assessment of future changes in daily precipitation likely leads to misrepresentation of causes and impacts. We show that the short-lived and intermittent nature of most rainfall extremes need at least hourly data to be properly characterized, otherwise heavy rainfall is poorly detected. Analyzing higher frequencies also reveals aspects of extremes that cannot be addressed with daily data, such as changes in their intensity and duration. This is particularly relevant for risk and impact assessment studies because a significant part of changes in extremes occur at sub-daily scales. Such changes go unnoticed or, even worse, are misrepresented by daily rainfall amounts.
Observing the climate impact of large wildfires on stratospheric temperature
Authors: Stocker Matthias , Ladstädter Florian , Steiner Andrea K.
Published: March 2022

In the future, large wildfires are expected to become more frequent and intense. Not only do they pose a serious threat to people and ecosystems, but they also affect the Earth's atmosphere. Aerosols from large wildfires can even reach the stratosphere where they can linger for months to years. However, little is known about their impact on climate. In particular, the potential of large wildfires to cause temperature changes in the stratosphere has hardly been studied.

In our study, we analyze two extreme wildfire events, those in 2017 in North America and those in 2019/20 in Australia, using new satellite observational data. We find strong effects of the fires on the atmospheric temperature structure and short-term climate in the stratosphere. The results show significant warming of the lower stratosphere by up to 10 K within the aerosol clouds emitted by the wildfires immediately after their formation. The climate signal in the lower stratosphere persists for several months, reaching 1 K for the 2017 North American wildfires and a remarkable 3.5 K for the 2019/20 Australian wildfires. This is stronger than any signal from volcanic eruptions in the past two decades. Such extreme events potentially influence the atmospheric composition and stratospheric temperature trends, underscoring their importance for future climate.

Improved knowledge of the temperature signals from extreme wildfires is particularly important for trend analysis. Our ongoing research on this topic aims to further improve the separation of natural variability from anthropogenic influences in climate trend detection, especially in the stratosphere.
Morphological evolution (1985-2021) and sedimentological study of the Essaouira bay and the mouth of Oued Ksob (Morocco)
Authors: Ezzahzi Salma , Algouti Abdellah , Algouti Ahmed
Published: March 2022

 

Abstract

The coastline of Essaouira is located on the Atlantic coast of Morocco. The bay of this city is a large sandy system strongly marked by coastal and fluvial dynamics which makes it a perfect example to understand the process of sedimentology in a bay area.

The use of satellite imagery allows us to determine the morphological evolution of the bay of Essaouira and the mouth of Oued Ksob. The results of our study show the evolution of the coastline of the bay of Essaouira with areas in erosion and others in accumulation. The analysis of satellite images allows us to distinguish three very different sectors: the first which is north of the estuary of Wadi Ksob because of its closed nature (bay), this area receives most of the flood contributions of Wadi Ksob, which helps to maintain its morpho-sedimentary balance. The second sector, which is composed of the estuary and the mouth of the Wadi Ksob, is characterized by a hydrodynamic both fluvial and maritime. The third sector is located south of the estuary of Wadi Ksob, this sector is an open beach that is not affected by the presence of an obstacle which is the island of Mogador.

The sedimentological study is carried out on four different areas which are: the dunes, the mouth of Wadi Ksob, the area south of the estuary and the area north of the mouth. Several analyses were carried out namely: granulometry, morphoscopy, calcimetry and X-ray diffraction.

The granulometric, morphoscopic, calcimetric analyses and the results obtained by X-ray diffraction as well as the presence of certain minerals confirm that the origin of the sediments studied is both continental and marine. In addition to the natural factors that condition the morphological evolution of the whole coastline of Essaouira, the island of Mogador presents an obstacle and plays an important role on the morphogenesis as well as the sedimentation along the coastline

Keywords: coastline, coastal dynamic, fluvial dynamic, bay, satellite images, oued Ksob, mouth, sedimentologicalstudy, granulometry, morphoscopy, calcimetry, X-ray diffraction
Estimating uncertainties in the back-mapping of the fast solar wind
Authors: Koukras Alexandros , Keppens Rony , Dolla Laurent
Published: March 2022

Although the sources of the fast solar wind are known (the coronal holes), the exact acceleration mechanism of the fast solar wind is still not fully understood. An important factor that can improve our understanding is the combination of remote sensing and in-situ measurements.

In order to combine them, it is necessary to accurately identify the source location of the in-situ solar wind with a process called back-mapping. Back-mapping consists mainly of two parts.
The first one is the ballistic mapping where the solar wind radially draws the magnetic field into the Parker Spiral, down to a point in the outer corona.
The second one is the magnetic mapping where the solar wind follows the magnetic field line topology down to the solar surface. The magnetic field in this region is derived from a global model, like the potential field source surface extrapolations (PFSS).

In this study we focus on this back-mapping of the fast solar wind and try to determine all the uncertainties and sources of error that can affect the final location deduced on the solar surface. We compare different models for the ballistic mapping and also for the magnetic mapping and explore which free parameters have the greatest effect in the back-mapped locations.
Finally, we provide an uncertainty estimation for the back-mapped footpoints and compare our results with existing frameworks, like the Connectivity-Tool of IRAP.
Links between land cover change and climate in the Horn of Africa
Authors: Muktadir Md Abdul , Koppa Akash , Claessen Jeroen , MacLeod David A , Singer Michael , Miralles Diego G.
Published: March 2022

Land use and land cover change significantly influence regional energy budgets, and hydrological and biogeochemical cycles which may occur from both anthropogenic and natural disturbances. Likewise, vegetation may also respond dynamically to climate. In the past decades, the Horn of Africa has been hit by several droughts and heatwaves causing severe economic, environmental, and social damage. To evaluate and mitigate such impacts, it is necessary to establish and quantify the linkage between land cover change and regional climate. This study presents an observational analysis of recent (2001–2019) historical changes in land cover and land use and their relation to climate in the Horn of Africa. 

Firstly, we evaluate changes in land cover using the Moderate Resolution Imaging Spectrometer (MODIS) dataset. Results indicate steady expansion of grasslands (net gain is 1.2% of total area) and an opposite pattern for open shrublands during the period 2001–2016. Importantly, deforestation of evergreen broadleaf forest (0.3% of the total area) is also noticeable in continuous fractional vegetation cover (FVC) analysis. Next, the Global Database of Historical Yields (GDHY) is explored to identify the yield trends for two main cereals: maize and wheat.  Wheat yield shows increasing trends in the northern and southern parts, while maize yields increase in Ethiopia and mildly decrease in Kenya. To quantify the adverse impact of drought on yields, three drought indices are used: (a) Standardized Precipitation Evapotranspiration Index (SPEI), (b) self-calibrating Palmer Drought Severity Index (scPDSI), and (c) Standard Evapotranspiration Deficit Index (SEDI). The analysis identifies SPEI12 as arguably the best performing drought index for monitoring and forecasting impacts on yields in this region. 

Finally, a Conditional Spectral Granger Causality (CSGC) algorithm is employed for understanding the influence of climate variability on vegetation dynamics. Although the influence of climatic factors (i.e., precipitation, temperature, and solar energy radiation) on vegetation dynamics is heterogeneous, given the wide spectrum of climate regimes in the region, an overall increased influence of temperature on vegetation dynamics is revealed. In conclusion, the observational evidence indicates that climate plays an important role as a driver of both crop and natural vegetation change in the Horn of Africa. 
Cascading supraglacial drainage observed to cause large-scale acceleration and uplift during winter in Greenland
Authors: Maier Nathan , Andersen Jonas , Mouginot Jeremie , Gimbert Florent , Gagliardini Olivier
Published: March 2022

On land-terminating regions of ice sheets, large and transient changes in surface motion are not expected outside of summer due to the lack of concurrent melt forcing.  Here, we document the dynamic response to a cascading lake drainage that occurred during winter in Greenland using a high-resolution DInSAR timeseries (6-day) acquired from Sentinel-1 and optical imagery from Landsat-8 and Sentinel-2. A total of fifteen supraglacial lakes and several smaller supraglacial water features were identified to have drained during the event resulting in a velocity wave that propagates from the inland regions to the margin. Along the wave path, speeds increase up to three times pre-drainage velocities as the wave passes. Bifurcation of the velocity wave during the event implies at least two distinct subglacial flood pathways develop which drain from the margin over 100 km apart. By tracking the wavefront, we estimate the wave velocity through the event which we infer to be similar to the drainage velocity. Wave speeds of between 0.04 and 0.28 m s-1 suggests the subglacial flood propagates mainly through an inefficient drainage system. Using temporally overlapping portions of two DInSAR velocity maps which have an accuracy of greater than 0.1 m yr-1, we decompose the signal and demonstrate some of the motion is a result of surface uplift which constrains locations of likely flow pathways. Overall, our results demonstrate a sustained dynamic response to melt forcing can occur in the absence of surface melt. This indicates melt-induced ice motion changes are not limited to summer and transient winter dynamics might commonly occur as stored meltwater is released.
Global patterns of leaf traits based on optimality theory 
Authors: Dong Ning , Dechant Benjamin , Prentice Iain Colin
Published: March 2022

Plant functional traits are a key component of land vegetation models. We present global maps of specific leaf area (SLA) and leaf nitrogen content (N) by mass and area, derived from optimality principles. Leaf N per unit area (Narea) is proposed to be determined primarily by the amount of leaf tissue (is related to LMA = 1/SLA) and its metabolic activity (is related to  carboxylation capacity at 25˚C, known as Vcmax,25). SLA is predicted via optimality hypothesis that LMA maximizes average net carbon over the life cycle of the leaf, with separate calculations for evergreen and deciduous plant types. Global maps then use a remote sensing-based land cover product to assign fractional coverage of each type. Vcmax,25  is predicted via the coordination hypothesis, which posits that Vcmax under current growth conditions tends towards a value that balances the Rubisco- and electron transport-limited rates of photosynthesis.  Predicted trait values are compared to in-situ observations, showing good agreement for all three traits. Predicted global distributions are further compared with recently developed, data-based global trait maps. This research indicates how an optimality perspective can help to improve our understanding of vegetation functional diversity and ecosystem function, and potentially enhance vegetation models.
Quasi-universal relationship for alluvial river long-profile evolution
Authors: Wickert Andrew , İşcen B. Nilay
Published: March 2022

Alluvial rivers aggrade and incise by moving sediment while simultaneously evolving their hydraulic geometries. For both gravel- and sand-bed rivers, stress-based criteria for equilibrium channel width in turn maintain a constant bed shear stress and therefore linearize the sediment-transport response to changing river discharge. Here we demonstrate that realistic sediment-transport and width-closure relationships yield a stream-power form for sediment discharge. Differentiating this in space (i.e., taking the divergence) yields a slightly nonlinear diffusion equation that describes long-profile evolution. This simple equation-coupling work suggests that a single equation may suffice to describe river long-profile evolution from the bedrock--alluvial transition to the point at which backwater effects become significant.
Holocene climate variability in south east Australia; inferred from oxygen isotopes in sedimentary cellulose at Lake Surprise, Victoria.
Authors: Dharmarathna Asika , Tyler Jonathan , Barr Cameron , Tibby John , Jones Matthew , Ankor Martin , Cadd Haidee , Gadd Patricia , Hua Quan , Child David , Zawadski Atun , Hotchkis Michael , Zolitschka Bernd
Published: March 2022

South east Australia experienced periods of multi-year droughts particularly within the last 2 millennia. However, given the limited evidence from smaller number of sites and scarcity of  quantitative, high-resolution climate records, it is largely unknown whether these droughts are a feature of climate through the Holocene and the extent to which they are experienced throughout the region. Where conditions are suitable, oxygen isotopes preserved in lake sediments are a useful tool for reconstructing past climate and environmental conditions. Here, we present preliminary results of a Holocene length record from Lake Surprise in western Victoria, from which we analysed δ18O of aquatic cellulose as a proxy for lake-water δ18O, complemented by organic carbon/nitrogen ratios, organic carbon isotopes and XRF (ITRAX) inferred elemental composition. Our interpretation of the palaeo-data is supported by ~3 monthly monitoring of water and sediment geochemistry to track the modern hydrology of the lake. Our preliminary results show a strong positive correlation between precipitation and sedimentary calcium (carbonate deposition) over the last 150 years, likely linked to changes in primary productivity. The aquatic cellulose δ18O record through Holocene is also correlated with carbonate concentration, reinforcing our interpretation of CaCO3 deposition in the lake during wet periods. The cellulose δ18O record indicates a trend of gradually increasing aridity from early to late Holocene, with a notable extremely dry phase over the last 2 ka. Comparison of the cellulose δ18O record with high-resolution Holocene climate records indicates that multiple climate drivers such as ENSO intensification and Antarctic warming are strongly linked to increasing aridity of the region. Further work will focus on both increasing the resolution of the record to better identify the frequency and duration of key events and on quantifying natural hydroclimate variability, particularly via lake hydrologic modelling to better constrain the paleoclimate record.
Fine-root biomass and soil properties across Peruvian forests 
Authors: Salinas Norma , Cosio Eric , Tito Richard , Roman-Cuesta Rosa Maria , Nina Alex , Boza Tatiana , Cruz Rudi , Pedraza Miguel
Published: March 2022

To know the quantity of fine root biomass is crucial to understanding ecosystem structure and function. Soil characteristics and fertility are mainly determined by fine root dynamics, the turnover of this material is a major contribution of organic matter to soil structure and mineral nutrient cycles, and also the main source of carbon storage. Many studies of forests are mainly estimates of above-ground biomass. Here we report on differential patterns of fine root biomass allocation in Peruvian forests. Peru is divided into three large sub-regions, Amazon, Andean, and coast. These different ecosystems have also around 84 of the 103 ecosystems types and 28 of the 32 climates on the planet. A field study was conducted installing one-hectare permanent plots in each sub-region, this research was part of an intensive monitoring effort of the carbon cycle and functional traits in primary and secondary forests. To evaluate fine root biomass, 1 m2 cross-section pits were set up in the plots where soil samples were collected every 10 cm up to 1 m depth and every 25 cm up to 2 m depth. Roots were retrieved and sorted into different diameter categories ≤0.5, 0.5 - 2.5, 2.5 - 5, and> 5 cm. Samples were rinsed with tap water over a 500-um sieve to loosen the soil and facilitate root sorting and to ensure that the sieve was fine enough to retain the finer roots. The roots after sorting were weighed fresh and then dried at 80°C for 48 hours, weighed to the nearest 0.0001 g, and stored in plastic vials for chemical analysis.

Total root biomass measurements displayed strong regional differences. Coastal dry forest at 370 to 422 m in elevation, where a one ha plot can support 651-681 stems (> 10 cm dbh) had root biomass values ranging from 7960 kg ha-1 to 8130 kg/ha-1. Andean forest plots at 1780 m.a.s.l., with 586 stems contained 17020 kg ha-1 and Amazonian forest at 415 m.a.s.l., with 689 stems, had 33410 kg ha-1 fine root biomass. Our results support the hypothesis that large root biomass in tropical forests is related to ecosystem type, climatic variables (temperature and moisture), and nutrients. The low bulk density and fine root biomass in tropical forests are inversely related to temperature and moisture. Fine-root turnover decreased with soil depth, which can also have important implications for the soil carbon stock and C cycling.
Assessing the long-term evolution of abandoned salinized farmland via temporal remote sensing data
Authors: Zhao Liya
Published: March 2022

Salinization in arid or semiarid regions with water-logging limits cropland yield, threatening food security. The highest level of farmland salinization, that is, abandoned salinized farmland, is a trade-off between inadequate drainage facilities and sustainable farming. The evolution of abandoned salinized farmlands is closely related to the development of cropping systems. However, detecting abandoned salinized farmland using time-series remote sensing data has not been investigated well by previous studies. In this study, a novel approach was proposed to detect the dynamics of abandoned salinized farmland using time series multi-spectral and thermal imagery. Thirty-two years of temporal Landsat imagery (from 1988 to 2019) was used to assess the evolution of salinization in Hetao, a two-thousand-year-old irrigation district in northern China. As intermediate variables of the proposed method, the crop-specific planting area was retrieved via its unique temporal vegetation index (VI) pattern, in which the shape-model-fitting technology and the k-means cluster algorithm were used. The desert area was stripped from the clustered non-vegetative area using its distinct features in the thermal band. Subsequently, the abandoned salinized farmland was distinguished from the urban area by threshold-based saline index (SI). In addition, a regression model between electrical conductance (EC) and SI was established, and the spatial saline degree was evaluated by the SI map in uncropped and unfrozen seasons. The results show that the cropland has constantly been expanding in recent decades (from 4.7*105 ha to 7.1*105 ha), while the planting area of maize and sunflower has grown and the area of wheat has decreased. Significant desalinization progress was observed in Hetao, where both the area of salt-affected land (salt-free area increased approximately 4*105 ha) and the abandoned salinized farmland decreased (reduced from 0.45 *105 ha to 0.19 *105 ha). This could be mainly attributed to three reasons: the popularization of water-saving irrigation technology, the construction of artificial drainage facilities, and a shift in cropping patterns. The decrease in irrigation and the increase in drainage have deepened the groundwater table in Hetao, which weakens the salt collection capacity of the abandoned salinized farmland. The results demonstrated the promising possibility of reutilizing abandoned salinized farmland via a leaching campaign where the groundwater table is sufficiently deep to stop salinization.
Previously unknown topographic features beneath the Amery Ice Shelf, East Antarctica, revealed by airborne gravity
Authors: Yang Junjun , Guo Jingxue , Greenbaum Jamin S. , Cui Xiangbin , Tu Liangcheng , Li Lin , Jong Lenneke M. , Tang Xueyuan , Li Bingrui , Blankenship Donald D. , Roberts Jason L. , van Ommen Tas , Sun Bo
Published: March 2022

The seafloor topography under the Amery Ice Shelf steers the flow of ocean currents transporting ocean heat, and thus is a prerequisite for precise modeling of ice-ocean interactions. However, hampered by thick ice, direct observations of sub-ice-shelf bathymetry are rare, limiting our ability to quantify the evolution of this sector and its future contribution to global mean sea level rise. We estimated the seafloor topography of this region from airborne gravity anomaly using simulated annealing. Unlike the current seafloor topography model which shows a comparatively flat seafloor beneath the calving front, our estimation results reveal a 255-m-deep shoal at the western side and a 1,050-m-deep trough at the eastern side, which are important topographic features controlling the ocean heat transport into the sub-ice cavity. The gravity-estimated seafloor topography model also reveals previously unknown depressions and sills in the middle of the Amery Ice Shelf, which are critical to an improved modeling of the sub-ice-shelf ocean circulation and induced basal melting. With the refined seafloor topography model, we anticipate an improved performance in modeling the response of the Amery Ice Shelf to ocean forcing.
Primary structures of granite and following weathering schemes define landslide behavior in granite areas.
Authors: Chigira Masahiro
Published: March 2022

Granite is distributed all over the world and one of the rock types that are very susceptible to various kinds of mass movements including rockfall, rock slide, debris slide and debris avalanche. For example in Japan, Hiroshima rainstorm disasters in 1999, 2014, and 2018, and southern Miyagi rainstorm disaster induced by typhoon 19 in 2019. This is because its special characteristics of formative processes and weathering behavior. The primary structures of granite have long been believed as orthogonal cooling joints since the pioneer work of Cloos (1921, 1922), but we found that a granite body has columnar joints near its roof using UAV and SfM. Whether granite has columnar joints or not leads to different mass movement types. Rock columns separated by columnar joints form high unstable rock towers or tors, which are susceptible to rockfalls. When rock columns are weathered under the ground, they form boulders surrounded by saprolite; when they are eroded to form hills they frequently fail during rainstorms and transform to debris avalanche or debris flow with high destructive potential because of large mass of boulders. Granite without columnar joints is not suitable for spheroidal weathering but is sheeted by unloading; sheeting forms dip slopes, on which rock slides occur. Some granite is micro-sheeted by unloading and micro-sheeted granite is weathered to form a loose soil layer beneath slope surfaces. Such soil layers are very prone to heavy rainfalls and frequently slide, transforming debris avalanches and debris flows.

Primary structures of granite and following weathering schemes thus define landslide behavior in granite areas.
Toward Optimal Rainfall – Hydrologic QPE Correction in Headwater Basins
Authors: Liao Mochi , Barros Ana
Published: March 2022

Large errors in Quantitative Precipitation Estimates (QPE) tied to remote-sensing retrieval algorithms remain a challenge especially in complex terrain with fast hydrologic response. We propose a new framework to derive dynamic hydrologic corrections of rainfall in headwater basins that constrains water budget closure at a desired time-scale and distributes transient rainfall corrections along runoff trajectories by Lagrangian backtracking constrained by realistic time-of-travel distributions.  Downscaled QPE products (250 m resolution) are applied first as input to a distributed hydrologic model to predict runoff trajectories and the event hydrograph at the basin's outlet.  Second, time-varying rainfall corrections are derived from the residuals between predicted and observed discharge at the outlet. Finally, the corrections are spatially distributed following the runoff trajectories backward (i.e. trajectories are used as streaklines originating at the basin's outlet). Because nonlinear interactions between rainfall, runoff and storage are transient, the corrections are applied recursively until the shape and volume of the predicted hydrograph are stable.  The framework is applied to ground-based (e.g. Stage IV) and satellite-based remote-sensing QPE (e.g. IMERG) associated with the 49 largest floods 2008-2018 in the Southern Appalachian Mountains, USA. The results show improvements in hydrograph prediction efficiency skill at 15min timescale from -0.5 to 0.6 on average and up to 0.9 for warm season events, bounding event runoff volume errors with a mean of 3%, and reducing time to peak errors by half an hour on average.  Corrected QPE exhibits nearly perfect correlation and no bias at high elevation gauge locations. Cumulative uncertainty in the water budget closure at event scale is less than the uncertainty in streamflow measurements. Error attribution shows strong organization of QPE corrections according to seasonal weather and rainfall regime, thus providing a path to generalization to ungauged mountain basins.
Optimal Estimation of Snow Related Parameters in Noah Land Surface Model Using an Evolutionary Algorithm
Authors: Park Seon Ki , Lim Sujeong , Cassardo Claudio
Published: March 2022

Snow processes in the land surface models (LSMs) include the snow cover fraction, snow albedo, and snow depth — all interacting with the atmospheric conditions. Most LSMs include parameters based on empirical relations, resulting in uncertainties in model solutions. In addition, such parameters often reflect only the local characteristics where the empirical relations are made. Therefore, the empirical parameters need to be optimized when they are applied to different regions. This study seeks the optimal snow-related parameters over South Korea where heavy snowfall events occur in the winter. The optimization is conducted using a micro-genetic algorithm (micro-GA) and the in situ and satellite observations for the snow depth, snow cover fraction, and snow albedo. The micro-GA is one of the evolutionary algorithms to search for the best potential solution based on natural selection and the survival of fitness. To represent the regional empirical parameters using the single-column model (e.g., Noah LSM), we selected the representative stations over South Korea to cover various vegetation types. Next, we identify which snow-related parameters can be optimized and suggest the optimal parameters using the micro-GA over South Korea. As a result, the Noah LSM simulations, using the optimized parameters, reduced the biases by 45.1% and 32.6 % for the snow depth and snow albedo, respectively, and the root mean square errors by 17.0 %, 8.2 %, and 5.6 % for snow depth, snow cover fraction, and snow albedo, respectively.
Multi-step vertical coupling from the troposphere to the thermosphere due to gravity waves
Authors: Becker Erich , Vadas Sharon L. , Goncharenko Larisa , Harvey V. Lynn
Published: March 2022

Multi-step vertical coupling (MSVC) describes a paradigm shift regarding the role of gravity waves (GWs) in the winter middle and upper atmosphere. It is well known that primary GWs propagate into the winter stratosphere and lower mesosphere, where they dissipate. However, since this process is localized in space and intermittent, secondary GWs are generated. These propagate into the lower thermosphere, dissipate, and generate tertiary GWs and so forth. Recent modeling and observational studies showed that secondary and tertiary GWs from MSVC are the predominant GWs in the upper mesosphere and in the thermosphere during wintertime. MSVC cannot be simulated with GW parameterizations as used in conventional whole atmosphere models.

In this presentation, we describe the HIgh Altitude Mechanistic general Circulation Model (HIAMCM), which resolves medium-scale GWs from the surface up to z~450 km, including MSVC induced by primary GWs from jets, fronts, and orography. This is made possible by combining a sufficiently high spatial resolution with advanced methods for turbulent and molecular diffusion. Furthermore, the HIAMCM can be nudged to MERRA-2 reanalysis in the troposphere and stratosphere. The nudging is performed in spectral space and restricted to horizontal wavelenghs larger than ~1500-2000 km. As a result, the generation, propagation, and dissipation of resolved GWs is not affected by the nudging and simulated like in the free-running model. We present recent applications of the HIAMCM regarding 1) the role of secondary GWs in the winter polar mesopause region, 2) the wintertime thermospheric GW hotspot over the Southern Andes/Antarctic Peninsula, and 3) the southward propagation of thermospheric GWs during daytime (as a driver for corresponding traveling ionospheric disturbances). Furthermore, we contrast the MSVC during the strong polar vortex period in December 2016 to the MSVC during the sudden stratospheric warming in January/February 2017.
Vegetation hinders sediment transport towards saltmarsh interior
Authors: Gourgue Olivier , Belliard Jean-Philippe , Xu Yiyang , Fagherazzi Sergio , Temmerman Stijn
Published: March 2022

The resilience of saltmarshes mainly depends on their ability to gain elevation by sediment accretion to keep pace with sea level rise, and tidal channels play a crucial role in the transport of sediments towards their interior. While feedbacks between geomorphology and vegetation are increasingly recognized as key drivers shaping a variety of tidal channel network structures, the resulting impact on long-term sediment accretion over the vegetated platforms has been poorly studied so far. Here, we compare two saltmarsh species with contrasting colonization strategies and morphological traits: Spartina marshes, characterized by patchy colonization patterns, encroaching tidal flats in small, isolated patches (1-10 m2) that slowly grow laterally (few m/year) with dense stands of tall stems; Salicornia marshes, characterized by more homogeneous colonization patterns, establishing quickly over large areas (100-1000 m2) with much less dense and shorter stems. Through different model scenarios (without vegetation, with Spartina plant traits, and with Salicornia plant traits), we investigate the impact of saltmarsh vegetation on self-organization of tidal channel networks, and the resulting consequences on long-term sediment accretion over the vegetated platforms, while disentangling the role of plant morphological traits (stem density, height, diameter) from colonization traits (patchy vs. homogeneous). In agreement with previous literature, we find that saltmarsh vegetation (especially denser Spartina) increases channel density (a measure of alleged efficiency with which channel networks serve the vegetated platforms, solely based on their geometric characteristics). However, by contrast with what is usually assumed, our results reveal that higher channel density does not necessarily lead to higher sediment accretion rates over the platforms. That is because vegetation (especially denser Spartina) increases friction and hinders sediment transport towards the platform interiors, leading to the formation of levees close to the channels and depressions away from them. Our results also suggest that plant colonization traits (patchy vs. homogeneous) have a dominant impact on sediment accretion during the colonization phase, but that plant morphological traits (stem density, height, diameter) prevail on the long term.
Asymmetry in the prediction skills of NMME models for springtime droughts and pluvials over East Asia
Authors: Kim Byeong-Hee , Kam Jonghun
Published: March 2022

Over East Asia, reliable forecasts of boreal spring droughts and pluvials can provide time window of opportunities to mitigate their adverse effects. Here, we aim to assess the seasonal prediction skill of boreal spring droughts and pluvials over East Asia (EA), using NMME and atmospheric-only global climate model (AGCM) simulations. Results show that NMME models show a better prediction skill of pluvials than that of droughts, indicating asymmetry in the prediction skill. This asymmetric tendency is also found in the prediction skill of sea surface temperature (SST) during the corresponding drought and pluvial years. Results from the AGCM simulations show asymmetry in the prediction skills of spring droughts and pluvials, indicating the limited predictability of SST-teleconnections in the model physics. The findings of this study prioritize a need to improve the representation of sea-air interactions during drought years in the current climate models.
Seismic attributes in unconsolidated near-surface sediments
Authors: Dietiker Barbara , Brewer Kevin , Cartwright Timothy , Crow Heather , Pugin Andre J.-M.
Published: March 2022

The calculation, analysis and interpretation of seismic attributes is an important tool in reservoir seismology and has been used since the 1950’s to improve the characterization of oil and gas fields around the world.

Recent applications of seismic attributes in the near surface use the coherency attribute to detect faults as well as average and normalized frequencies and similarity to map ground instability and image sinkholes. Seismic attributes are also used to assess unconsolidated oil sand reservoirs, to evaluate ocean/lake bottom responses from unconsolidated sediments, and to visualize the internal structure of mass transport deposits. In unconsolidated near-surface sediments seismic attributes are rarely used. This is likely due to the high variability present in the near surface.

Combined P-/S-attributes are difficult to obtain because of the large difference between P-wave and S-wave velocity, as well as frequency and resolution. Therefore, the most important step to obtain these combined attributes is performing depth conversions for the P- and S-wave reflection profiles that perfectly match horizons and features in the depth domain.

We present commonly used attributes calculated from a shear-wave reflection profile imaging the dome structure of an esker. Attributes calculated from the compressional-wave reflections are compared to the shear-wave attributes which benefit from higher resolution than P-wave attributes. We highlight the attributes which best enhance the general subsurface structure and list new information gained from different attributes.
Cosmogenic 10Be from uplifted bedrock marine terraces indicates revised Holocene earthquake intensity for northeast South Island, New Zealand
Authors: McLean Aidan , Dickson Mark , Norton Kevin , Wilcken Klaus , Stephenson Wayne , Litchfield Nicola
Published: March 2022

Sequences of Holocene marine terraces are widely used in paleoseismic research to understand the timing and magnitude of earthquakes along tectonically active coastal margins worldwide. But the potential for marine terraces to be destroyed through erosion after uplift can result in incomplete records of paleoseismicity as derived from terrace chronologies, leading to misinterpretations of the paleoseismic history of a region. Here, we present measurements across a unique set of exposed bedrock marine terraces in the north-eastern South Island, NZ, to quantify the ages and erosion rates of the surfaces and produce a new chronology for paleoseismic interpretation. Surface exposure dating and multi-nuclide approaches offer the potential to quantify marine terrace preservation and destruction, potentially elucidating where terraces may be missing or removed from a sequence. Needles Point, Marlborough, NZ exhibits three well defined bare rock marine terraces and a gravel covered shore platform which was recently uplifted ~2.5m in the MW 7.8 2016 Kaikōura earthquake. 10Be-derived ages for the platform surface and terrace 1 (T1) align with known ground surface rupturing earthquakes on the Kekerengu fault. T2 and T3 preserve older events not previously identified, potentially extending the earthquake record in this region. However, other known ground surface rupturing earthquakes on the Kekerengu fault are not preserved as terraces at Needles indicating that the preserved terraces at Needles Point do not therefore represent a full record of local paleoseismicity. As such, estimates of fault throw derived from these terraces would over-estimate earthquake magnitude.
Ring Current Electron Precipitation During Storm Events
Authors: Grishina Alina , Shprits Yuri , Wutzig Michael , Allison Hayley , Aseev Nikita , Wang Dedong , Szabo-Roberts Matyas
Published: March 2022

The particle flux in the near-Earth environment can increase by orders of magnitude during geomagnetically active periods. This leads to intensification of particle precipitation into Earth’s atmosphere. The process potentially further affects atmospheric chemistry and temperature.

In this research, we concentrate on ring current electrons and investigate precipitation mechanisms on a short time scale using a numerical model based on the Fokker-Planck equation. We focus on understanding which kind of geomagnetic storm leads to stronger electron precipitation. For that, we considered two storms, corotating interaction region (CIR) and coronal mass ejection (CME) driven, and quantified impact on ring current. We validated results using observations made by POES satellite mission, low Earth orbiting meteorological satellites, and Van Allen Probes, and produced a dataset of precipitated fluxes that covers energy range from 1 keV to 1 MeV.
Influence of vegetation and flood regimes on deltaic floodplain deposition
Authors: Composta Jacopo , Pinton Daniele , Canestrelli Alberto , Carniello Luca
Published: March 2022

In microtidal environments, sedimentation occurring during high freshwater discharges is essential to prevent floodplains from drowning with rising sea levels. Vegetation has long been considered as one of the main drivers of overbank deposition because it reduces flow velocity on the floodplains (trapping effect). However, it has recently been shown that dense vegetation patterns can behave as a barrier for sediments and water fluxes (buffering effect), thus reducing the mass of sediments flowing from the river to the floodplains and increasing the seaward export of sediments through the channel. The buffering effect has been shown to prevail over the trapping effect only in the Wax Lake Delta and only for a few specific hydrographs. Therefore, there is a need to systematically investigate the impact of floodplain vegetation on sediment trapping and buffering. To this purpose, we conduct numerical simulations with the Deltf3D model to analyze sediment deposition over floodplains for several different rivers and floodplains geometries, vegetation characteristics, and flood conditions (i.e., peak magnitude, duration, and hydrograph skewness). The model domain consists of a simplified riverine environment, constituted of a rectilinear channel surrounded by rectangular floodplains. Our results indicate that besides the trapping and buffering effects, there is a third important effect, which we name piling-up effect, consisting of a general increase of water level along the river for higher vegetation densities and heights. This increase favors higher fluxes of water and sediments from the river into the floodplains. We identify the parameter space for which trapping and piling-up effects are larger (or smaller) than the buffering effect, thus leading to more (or less) deposition in the vegetated case than in the unvegetated one. We also identify the vegetation characteristics that maximize floodplain deposition given the river and floodplain geometries. This information can be used for targeted floodplain restoration strategies.
CORDEX Flagship Pilot Study on Urbanization - URBan environments and Regional Climate Change (URB-RCC)
Authors: Halenka Tomas , Langendijk Gaby
Published: March 2022

Cities play fundamental role on climate at local to regional scales through modification of heat and moisture fluxes, as well as affecting local atmospheric chemistry and composition, alongside air-pollution dispersion. Vice versa, regional climate change impacts urban areas and is expected to increasingly affect cities and their citizens in the upcoming decades, because the share of the population living in urban areas is growing, and is projected to reach about 70% of the world population up to 2050. This is especially critical in connection to extreme events, for instance heat waves with extremely high temperatures exacerbated by the urban heat island effect, in particular during night-time, with consequences for human health.

In 2013, the CORDEX community identified cities to be one of the prime scientific challenges. Therefore, we proposed this topic to become an activity at CORDEX platform, within the framework of so called flagship pilot studies, which was accepted and the FPS URB-RCC activity has been started in May 2021.

The main goal of this FPS is to understand the effect of urban areas on the regional climate, as well as the impact of regional climate change on cities, with the help of coordinated experiments with urbanized RCMs. While the urban climate with all the complex processes has been studied for decades, there is a significant gap to incorporate this knowledge into RCMs. This FPS aims to bridge this gap, leading the way to include urban parameterization schemes as a standard component in RCM simulations, especially at  high resolutions.

From the perspective of recent regional climate models development with increasing resolution down to the city scale, proper parameterization of urban processes is important to understand local/regional climate change. The inclusion of the individual urban processes affecting energy balance and transport (i.e. heat, humidity, momentum fluxes) via special urban land-use parameterization of local processes becomes vital to simulate the urban effects properly. This will enable improved assessment of climate change impacts in the cities and inform adaptation and/or mitigation options, as well as prepare for climate related risks (e.g. heat waves, smog conditions etc.). More detailed discussion of the RCMs simulations available with urban parameterization and methods already in use will be presented.