bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics and morphology of sinking particles in the equatorial Atlantic during the 2021 Atlantic Nino
Authors: Habib Joelle , Stemman Lars , Climent Pierre , Accardo Alexandre , Baudena Alberto , Tuchen Franz Philip , Brandt Peter , Kiko Rainer
Published: March 2024

The equatorial upwelling system is characterized by a strong seasonal cycle with relatively cold sea surface temperature (SST) and enhanced primary production in the “cold tongue region” of the eastern basin during boreal summer. During the boreal summer of 2021, the equatorial Atlantic witnessed its most intense warm event since the beginning of satellite observations, which is assumed to have a direct impact on the carbon cycle. Here we use data from a BGC Argo float, deployed in the equatorial upwelling region in order to investigate the production peaks of marine particles during two distinct periods: the decay period of the anomalous weak cold tongue and the period of secondary cooling in boreal winter. In situ images of plankton and particles and physical and biogeochemical data provided by the Underwater Vision Profiler 6 (UVP6) and various sensors mounted on the float were analyzed in conjunction with satellite data (sea surface height, SST, ocean color). The float covered the period between 13 July 2021 and 23 March 2022 drifting eastward from 23-7.4°W along the equator and conducting 2000 m profiles every three days. Our data revealed the occurrence of two blooms with high surface chlorophyll concentrations accompanied by the presence of two carbon export events reaching at least 2000 m depth. Both events exhibited high carbon flux at the mixed layer with a flux of 106±5 mgC.m-2d-1 during the first event compared to 122±17 mgC.m-2d-1 during the second while flux between both events remained below 89 mgC.m-2d-1. However, a distinction in the vertical extent of these events was recorded as there was a slightly higher flux at 2000 m for the winter boreal, 30% higher, suggesting a difference between the carbon attenuation flux export associated with the primary upwelling season with the one observed during the secondary cooling period in the boreal winter. The characterization of the morphology of detritus using in situ imaging and clustering method revealed the presence of five different morpho-types with different sinking properties. Two primary classifications—large and small dense aggregates—emerged as the predominant exported detritus to depths while porous aggregates were more concentrated in the surface layer. Our study revealed a dynamic interaction between various layers, involving carbon production in the surface layer, succeeded by its subsequent export to deeper layers. Finally, this study offers new insights into particle dynamics and the morphology of sinking particles within the equatorial region.
The Goshogake hydrothermal field (northern Japan): purely geothermal or hybrid sediment-hosted?
Authors: Mazzini Adriano , Naizhong Zhang , Etiope Giuseppe , Jajalla Mellinda Aimee , Nakagawa Mayuko , Gilbert Alexis
Published: March 2024

The Goshogake hydrothermal field in Tohoku, northern Japan, is located on the western flank of the Akita Yakeyama volcano. This N-S elongated field extends over ~20-25 acers and is placed over a tectonic discontinuity that controls the migration of hydrothermal fluids. A variety of surface degassing manifestations can be distinguished including small hydrothermal lakes, clustered bubbling pool fields, active mud erupting gryphons, sulfur-rich fumaroles and localized apparently oil-rich pools. So far it remains unclear if this system and the released gases are purely magmatic or if is also involved the migration of mantle-derived fluids interacting with buried sedimentary deposits. Here we report the result of field observations and fluid samples analyses. The measured temperatures of the active seepage sites range from 33 to 97 °C (in large part higher than 90 °C), while pH is overall low at all sites (i.e. ~2.5).Gas analyses reveal that all the active sites are CO2-dominated with slightly higher CH4 content in the colder and mud seeping sites. While CO2 has a distinct mantle-derived isotopic signature, the origin of methane is still debated. The apparent d13C thermogenic signature of methane, could also be related to an abiotic origin which would be consistent with a CO2-dominated geothermal system. The presence of oil, if confirmed, could be related to shallow-sourced hydrothermal oil (e.g. similar to that described by Didyk and Simoneit (1989), or, more interestingly, could indicate that this active site is part of a petroleum system potentially linked with deeply buried lacustrine sediments that fill a 1-Ma-caldera formed after a ignimbrite eruption. The possible presence of these deposits in the erupted mud has been suggested by Komatsu et al., (2019) based on mineralogical analyses.To further test this hypothesis, we are now conducting multiple analyses on the samples recovered from 6 locations at the Goshogake field, including the isotope analysis of water, gas, oil and mud compositions to unravel the source of these fluids as well as the reactions that took place at this site. If confirmed, Goshogake could potentially be the first example of known sedimentary hosted geothermal system in Japan. We speculate that targeted fieldworks would likely identify other hybrid systems in the country.
Lagrangian analysis of ice supersaturated air masses in connection with low level fronts of extratropical cyclones
Authors: Reutter Philipp , Niebler Stefan , Miltenberger Annette , Spichtinger Peter
Published: March 2024

Ice supersaturation is often found in the upper troposphere. The so-called ice supersaturated regions (ISSRs), i.e. air masses in the status of supersaturation with respect to ice, are formation regions of in-situ cirrus clouds. While an ISSR alone has a rather small effect on the radiation budget, this changes significantly when cirrus clouds develop within the ISSR. Hence, the transition from an ISSR to a cirrus cloud has important implications. In order to understand how ISSR and the embedded in-situ cirrus clouds form and develop, the transport pathways of water vapour have to be understood.Therefore, to better understand the life cycle of extratropical ice-supersaturated regions (ISSRs), we utilize backward and forward trajectories initiated within ISSRs and analyze them. Furthermore, we connect these trajectories with information about the location of low-level frontal systems to investigate connections between ISSRs and extratropical cyclones. Particularly interesting is the relative position to the so-called warm conveyor belt (WCB) trajectories. 
Towards Understanding the Effects of Climate and Land Cover Change on Dissolved Organic Carbon Export in Temperate Forest Catchments
Authors: Nguyen Tam , Kumar Rohini , Ledesma José L.J. , Ebeling Ebeling , Fleckenstein Jan H. , Musolff Andreas
Published: March 2024

The amount of dissolved organic carbon (DOC) in surface waters is an important water quality indicator. High levels of DOC in surface waters cause negative impacts on the aquatic ecosystem (e.g., via reducing light penetration and increasing water temperature) and increase the water treatment cost for drinking water supply. DOC mobilization and export from catchments into streams are hydrologically controlled and strongly affected by catchment-specific characteristics (such as topography, soils, and land cover type) and climatic factors. In this study, we developed a simplified process-based model that explicitly includes the hillslope, riparian, and groundwater compartments with the hydro-biogeochemical concept mainly based on the mesoscale Hydrologic Model (mHM) and INCA-Carbon models. The proposed model also allows dynamic carbon input from litterfall and root breakdown. We hypothesize that such a model is needed to understand the role of different catchment compartments and land cover and climate change on instream DOC export. We applied the proposed model for instream DOC simulation in four temperate forest and agriculture catchments located in the Harz Mountains, Germany. Here, we calibrated the model for the period which includes drought years (2018-2019) and the subsequent forest dieback (starting from 2018). The models showed satisfactory results in terms of instream DOC concentrations. Here, we will further evaluate if the model provides the right results for the right reasons by analyzing the physical soundness of the internal carbon export dynamics among different model compartments from our calibrated model. Such evaluation is important when further applying this modeling concept to other areas under similar circumstances.
Impact of drought on Sentinel-2 derived winter wheat growth dynamics and the relation to soil properties
Authors: Sjulgård Hanna , Graf Lukas , Colombi Tino , Hirte Juliane , Keller Thomas , Aasen Helge
Published: March 2024

Drought can severely limit plant growth, and in turn crop productivity, and poses challenges to global food production. Plant growth can be measured with the Green Leaf Area Index (GLAI), and satellite images offer opportunities to estimate GLAI at field and landscape scales. Analysing satellite-estimated GLAI development at the landscape level could reveal new insights into how soil characteristics influence crop performance under various weather conditions, which in turn could provide information on how to mitigate the impacts of extreme weather. In this study, we quantified winter wheat growing patterns in two years with contrasting weather conditions (2018: early summer drought; 2021: normal growing conditions) on farmers’ fields using Sentinel-2 derived GLAI, and assessed the impacts of drought on GLAI dynamics. Moreover, we tested whether soil properties can explain differences in GLAI dynamics between a dry and a normal weather year.Sentinel-2 scenes were downloaded from Microsoft Planetary Computer and the radiative transfer model PROSAIL was used to estimate GLAI throughout the winter wheat vegetative growing season on farmers’ fields in the south of Sweden. Characteristic GLAI parameters such as growth rate, area under the curve, peak GLAI and timing of the peak were calculated from the GLAI time series. The impact of drought on winter wheat growth was assessed by comparing the GLAI parameters between the dry year 2018 with the normal weather year 2021. In addition, the GLAI parameters were related to several biological, chemical and physical soil properties measured on the farmers’ fields.The results showed lower GLAI parameters during the dry year compared to the normal weather year on the farmer’s fields. For some fields, there was a large difference between the years while for other fields a smaller difference. Plant available water content was found as the most important soil property in explaining the differences in GLAI parameters between the years. Our study demonstrates that satellite image analysis of GLAI dynamics can be used to identify plant stress responses on farmer’s fields. By analysing a dry and a normal year, we show that the impacts of drought can vary considerably between fields, and by combining GLAI estimates with measurements of soil properties, we identified plant available water content as a key soil property to explain differences between years. Thus, our results contribute to knowledge towards developing soil management strategies to mitigate the impacts of extreme weather.
Multi-source analysis of recent changes in global terrestrial evapotranspiration
Authors: Thomson Johanna , Markonis Yannis
Published: March 2024

With rising temperatures, we can expect significant changes in the terrestrial water cycle (TWC).  Evapotranspiration (ET) represents a significant component of the TWC, linking the water, energy, and carbon cycle of the land and atmosphere. Although recent reviews showed that ET has been increasing and even accelerating since the 1980s due to an increase in the LAI (Yang et al., 2023), some studies suggest that ET might be declining (Kim et al., 2021). So, is the increase of ET product dependent? Where in the world do we find disagreement?We processed 13 global ET products derived from reanalysis, remote sensing, synthesis, and land surface models thereby representing a wide variety of available data. For 2000-2019, we analyzed the ET slope per grid (0.25 deg 0.25 deg), and meaningful regions including biomes, land cover classes, Koeppen-Geiger regions, elevation classes, evaporation quantiles, and IPCC reference regions. Using indices for dataset similitude and concurrence, we created probability maps, which allow us to pinpoint hotspots of uncertainty and regions with a high likelihood of change.We confirm that ET has increased for 37 % of the terrestrial land from 2000-2019. However, the direction of change in ET for 36 % of the global land area was uncertain with various products showing significant (p > 0.05) negative and positive trends. The spatial distribution of uncertainty varies greatly spatially. For example, over 60% of the area of mangroves and tropical/subtropical moist broadleaf forests and over 40 % of the area of tropical/subtropical, flooded, and montane grass- and shrublands resulted in uncertain ET changes. Some IPCC reference regions (NWS, CAF, SAM, and NSA) resulted in over 70 % of the area in uncertain ET changes. This indicates that estimating changes in ET is still product dependent.By pinpointing the regions in which the ET products disagree on the magnitude and direction of change, we can lay the ground for the further improvement of TWC estimates.  On the other hand, dataset consensus can help to increase the credibility of hydrological and climate model evaluations and attribution studies. Overall, there is an urgent need to further constrain ET.    Kim, S., Anabalón, A., & Sharma, A. (2021). An Assessment of Concurrency in Evapotranspiration Trends across Multiple Global Datasets. Journal of Hydrometeorology, 22(1), 231–244. https://doi.org/10.1175/JHM-D-20-0059.1Yang, Y., Roderick, M. L., Guo, H., Miralles, D. G., Zhang, L., Fatichi, S., Luo, X., Zhang, Y., McVicar, T. R., Tu, Z., Keenan, T. F., Fisher, J. B., Gan, R., Zhang, X., Piao, S., Zhang, B., & Yang, D. (2023). Evapotranspiration on a greening Earth. Nature Reviews Earth & Environment, 4(9), Article 9. https://doi.org/10.1038/s43017-023-00464-3
Analysis of droughts and arid conditions in Central Asia using climate indices
Authors: Latinovic Milena , Selyuzhenok Valeria , Gafurov Abror
Published: March 2024

Droughts pose significant challenges to water resources, agriculture, and socioeconomic stability, particularly in regions susceptible to climatic extremes such as Central Asia (CA) with its complex topography and diverse ecosystem. In the past several years there has been a substantial decrease in water storage in the region which further could lead to socioeconomic instability. Water is mainly used for irrigation and hydropower production in the region.In CA, the availability of ground observations is restricted, with most of the measurement stations being outdated since the Soviet era with little or no data sharing between the countries. Consequently, the utilization of widely available remotely sensed data proves advantageous in overcoming these limitations and improving the accuracy of water availability assessment in the region.CA relies predominantly on water resources derived from the melting of snow and glaciers in the Pamir, Tian Shan, and Hindukush mountains. In the study, we consider the two largest upstream river basins, Amu Darya and Naryn, the eastern headstream of Syr Darya. These two largest rivers in CA are crucial sources of water in the region, supporting agriculture and the ecosystem in the whole of CA.The study specifically focuses on evaluating snow cover and Snow Water Equivalent (SWE) during the winter months, especially preceding the onset of drought periods, and the Total Water Storage (TWS) in the drought months. The objective is to comprehend and quantify the correlation between these climatic elements and historical droughts, utilizing the Drought Severity Index (DSI) and the widely used Standardized Precipitation Index (SPI).  DSI is based on the TWS value that is derived from the GRACE and GRACE-FO satellite missions. It shows a significant decrease in water storage in both basins since the start of the GRACE mission in 2002, with more intense arid conditions in the last 6 years. SPI-6 and SPI-9 based on precipitation and SWE data, show a slight increase in the trend in the Amu Darya basin, while in Naryn all indices show an increase in drought periods. This indicates that the arid conditions in the summer months in the Amu Darya basins are driven by human-induced water depletion. Finally, all indices can depict severe droughts in 2008, 2011 and 2018 in both basins. The study shows the potential of using globally available TWS data for drought assessment on a regional scale such as in CA.
Adaptation of satellite-based vegetation indices for different land use types
Authors: Zsigmond Tibor , Horel Agota
Published: March 2024

Remote sensing is an important data collection method for farmers and researchers to obtain up-to-date information on the state of vegetation. Due to efficiency and low cost of method, the satellite-based remote sensing also allows analysis at the catchment level. The aim of present study was to investigate the usability of satellite-based vegetation indices for different land use types while using ground-truth measurements for comparisons. The study area was a small agricultural catchment in Balaton Upland, Hungary. Four different land use types (forest, grassland, vineyard and cropland) were investigated, located on different angled slopes. In the vineyard there were three different inter-row managements investigated.In 2023 the field measurements were taken in every two weeks during vegetation period. Hand-held (H) sensor set was used to measure vegetation indices on the slopes of grassland, cropland, and the three vineyard sites. The Normalized Difference Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI) sensors were used to measure leaf reflectance. A hemispherical sensor set was used for each measurement. Additional handheld instruments were used for Leaf Area Index (LAI), and soil water content (SWC) measurements. The source of satellite-based data was Sentinel-2 (S2). At the same time as the field measurements 8 out of 13 available spectral bands were collected from S2 and used to calculate different spectral indices (e.g. NDVI or green chlorophyll index - GCI).The vegetation of different land use types varies considerably, which also affects the applicability of the vegetation indices. In 2023, the strongest correlation between NDVI of field measurement and satellite NDVI was for grassland (r=0.76). The highest overall NDVI values for both methods were observed in the vineyard with cover crop inter-row (H NDVI: 0.76, S2 NDVI: 0.56). PRI values for all land use types were most strongly correlated with the Red Edge 2 band (e.g. r=0.65 for grassland, r=0.69 for Cropland, r=0.70 for Vineyard C). The highest average leaf area index was measured for the forest (3.36), and the lowest in grassland (0.86). LAI showed good correlation with cropland GCI (0.86), moderate correlation with forest and tilled inter-row vineyard (0.50 and 0.55, respectively). PCA analysis showed that the cover crop and grassed inter-row did not, but most other land use types grouped distinctly.Acknowledgments: This material is based upon work supported by the Hungarian National Research Fund (OTKA/NKFI) project OTKA FK-131792. The research presented in the article was carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022 00008 project. The research was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA).
Radiative forcing and stratospheric ozone changes due to recent volcanic eruptions and major forest fires
Authors: Brühl Christoph , Lelieveld Jos , Rieger Landon , Santee Michelle
Published: March 2024

The chemistry-climate model EMAC was used to simulate the period 2019 to 2023 with tropospheric meteorology slightly nudged to ERA5 data. Volcanic SO2 injections were derived from aerosol extinction observations by OSIRIS and OMPS-LP which were also used for evaluation of the simulated aerosol, which includes organic particles from major forest fires that can linger in the lower stratosphere for more than 2 years. Our simulations consider several hundred explosive volcanic eruptions. The simulations of ozone chemistry include enhanced surface area density and fast heterogeneous chlorine activation on organic particles and will be compared with AURA-MLS observations. The effects of the major water vapour injection by the eruption of Hunga Tonga in 2022 on radiative transfer and chemistry were also analysed (as a contribution to SSIRC Hunga Tonga). For example, in 2022 the Hunga Tonga eruption increased the depth of the calculated  Antarctic ozone hole by about 12 DU. The Australian bushfire emissions enhanced the aerosol surface area which deepened the 2020 ozone hole by about 7 DU, with the largest changes near the vortex edge. The smoke effect is expected to increase with updated heterogeneous chemistry.The computed global instantaneous aerosol radiative forcing by Hunga Tonga at the top of the atmosphere was about -0.12 W/m2 in 2022. The injected water vapour by Hunga Tonga exerted a radiative forcing of about +0.04 W/m2 in the first four months after the eruption. By the end of 2022, it nearly vanished due to dynamical and chemical adjustments. The absorbing aerosol from the Australian and Canadian forest fire emissions changed the stratospheric aerosol forcing from -0.2 W/m2 to +0.3 W/m2 in January 2020, and in January 2022 the remaining effect was about 0.05 W/m2, reducing the negative forcing by the volcanoes. Continued interesting effects of the Hunga Tonga eruptions are expected for 2023, based on results from ongoing simulations.
Small-scale waves, big implications: a regionally refined perspective with the Whole Atmosphere Community Climate Model
Authors: Kupilas Marcin , Gardner Chester , Feng Wuhu , Guarino Maria Vittoria , Marsh Daniel , Plane John
Published: March 2024

State-of-the-art global chemistry-climate models such as WACCM cannot practically resolve the small-scale gravity waves (GWs) that are important in the mesosphere and lower thermosphere (MLT, ≈ 70-120km). A solution is the use of parametrizations that represent subgrid dissipating GWs (see e.g. Garcia et al., 2007). To reproduce key MLT features such as mesospheric jet reversals, pole-to-pole circulation and the summer mesopause, models rely on such schemes (McLandress, 1997; Holton & Alexander, 2000), though more development is needed. For example, WACCM tends to underestimate observed mesospheric densities of O, O3 and NO, and overestimate observed densities of the Na and Fe layers produced from cosmic dust ablation. Increasing evidence suggests a reason for this is a missing vertical transport from subgrid propagating GWs, and a solution has recently been achieved when these effects were included in the WACCM GW scheme (Guarino et al., 2023). In the current work, we resolve subgrid waves natively using WACCM with Regional Refinement (WACCM-RR). WACCM-RR provides the unprecedented opportunity to model the global climate up to altitudes of 140 km, and resolve individual regions down to as far as 1/32° at a low computational cost compared to global high resolution models. Trends from a model using a 1/8° grid over the Continental US  (1° elsewhere), when compared to a global 1° model, are consistent with comparisons of standard WACCM models, to models using our updated GW scheme. For example, mesospheric densities of O, O3 and CO2 are increased, as predicted. A surprising contrast is a globally warmer atmosphere, likely due to sensitivity of the meridional circulation to GW activity in the refined region. The results point to the applicability of WACCM-RR for detailed investigations of wave-transport processes, and their impact on MLT dynamics and composition. We point out remaining questions and challenges.
Seasonal variation in ecosystem and soil methane and nitrous oxide fluxes in a tropical rainforest
Authors: Brechet Laëtitia , Ibáñez Mercedes , Burban Benoît , Goret Jean-Yves , Stahl Clément , Bonal Damien , Jackson Rob , Janssens Ivan
Published: March 2024

Tropical forests play a key role in the global carbon balance and in natural climate change mitigation, as they account for 68% of global forest carbon stocks and represent up to 30% of global soil carbon stocks. However, major uncertainties remain regarding the long-term sustainability of their carbon sink capacity when considering the full greenhouse gas exchange, including methane (CH4) and nitrous oxide (N2O) fluxes, and accurately identifying and quantifying all sources and sinks.In this line, we present here original continuous high-frequency ecosystem (eddy covariance) and soil (automated chamber) CH4 and N2O flux data from a 2.5-year study in a seasonally wet tropical forest at the Guyaflux experimental site, French Guiana. The main objective of our study was to assess the seasonal patterns of CH4 and N2O exchange at the ecosystem and soil levels, and to identify the environmental drivers. Seasonal variations in ecosystem and soil CH4 and N2O fluxes were tremendous, with generally higher CH4 and N2O emissions in the wettest than in the driest season. Global radiation, soil water content and soil temperature were the main drivers of seasonal variation in ecosystem and soil CH4 and N2O fluxes. Furthermore, based on eddy covariance measurements of all greenhouse gases, i.e. CH4, N2O and CO2, the forest was overall a significant carbon sink (-1,875 ± 813 kgC ha-1 y-1, i.e. cumulative net ecosystem exchange), although the ecosystem shifted from a small sink to a small source of CH4 during the wettest season, and remained a more or less small but constant source of N2O. In contrast, soil fluxes in the upper part of the forest within the tower footprint were consistently a CH4 sink, while soil N2O fluxes shifted depending on the season, from a small N2O sink in the driest season to a small source in the wettest season.Our study shows that the carbon sink potential of the Guyaflux forest is not yet compromised by CH4 and N2O emissions. However, under the more frequent extreme conditions of contrasting soil water content and global radiation expected in the future, CH4 and N2O emissions may increase and thus reduce the forest carbon sink.
Simulating the impact of an AMOC weakening on the Antarctic Ice Sheet using a coupled climate and ice sheet model
Authors: Höse Anna , Kreuzer Moritz , Huiskamp Willem , Albrecht Torsten , Petri Stefan , Winkelmann Ricarda , Feulner Georg
Published: March 2024

Many model studies show that a shutdown of the Atlantic meridional overturning circulation (AMOC) causes reduced northward heat transport into the North Atlantic and a warming Southern Ocean in addition to shifts in large-scale atmospheric circulations. How these changing climate conditions could influence the present-day state of the Antarctic Ice Sheet is little studied even though observational data of AMOC strength show a slowdown trend over the last decades. The ocean current as well as the Antarctic Ice Sheet might reach climate tipping points triggering irreversible processes with consequences already on human time-scales. It's unclear whether increasing Southern Ocean temperatures due to a AMOC shutdown could accelerate basal melting rates, the critical parameter which in turn may induce tipping of the West Antarctic Ice Sheet.Here, a freshwater hosing that forces the shutdown of the AMOC is applied to the North Atlantic in a global climate model with an interactive ice sheet model for Antarctica. This model framework consists of the Parallel Ice Sheet Model (PISM) that is coupled to the CM2Mc global Earth system model via the ice shelf cavity model PICO (Potsdam Ice-shelf Cavity mOdel). PISM is interactively coupled to the ocean module in order to investigate feedbacks at the ice-ocean boundary, while the atmospheric forcing is prescribed. Preliminary results show that an AMOC shutdown results in warming sea surface temperatures in the southern hemisphere along with a small shift in the mid-latitude westerlies due to reduced northward heat transport, which is in line with previous studies. Antarctic marginal temperatures decrease, however, resulting in a reduction of Antarctic mass through increased calving and decreased basal melting.
Remote sensing estimation of cover crop biomass using machine learning algorithms in Denmark
Authors: Choudhary Komal , Butterbach-bahl Klaus , Dalgaard Tommy
Published: March 2024

Knowledge of total aboveground biomass (AGB) at harvest time, from site to national scales, is critical to understanding the potential for C sequestration and residue utilization in agricultural ecosystems. Cover crop biomass estimation models using an integration of remote sensing and field data represent a useful inversion technique. Here we present different approaches to estimating cover crop biomass in Denmark, using a variety of different datasets and methods, such as observational data of Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Ratio Vegetation Index (RVI), Precipitation (mm), Land surface temperature (oC), as well as crop grain production (statistical data) for the years 2013 – 2023, supplemented with data from national soil mapping (e.g. texture, SOC, pH) and a Digital Elevation Model (DEM for estimating slope, aspect, etc.). These data were used to develop a spatially explicit peak biomass model for wheat. Our results show that the cover crop biomass in Denmark showed significant spatial and interannual variation from 2013 to 2023, with the spatial and temporal distribution characteristics closely related to NDVI. The linear regression between peak biomass and NDVI yielded a R2 of 0.78, which could be further improved by also considering other information on soils, fertilization, and landscape characteristics. Our results indicate a high potential to estimate biomass for the cover crops based on combined information by remote sensing, soil mapping and field management practices. This information, in combination with biogeochemical modeling, will allow assessment of the potential of agricultural landscapes to provide estimates of regional availability of residues for the bioeconomy while maintaining or improving soil organic C stocks.
The technology of UAV based EM soundings for mineral exploration. 
Authors: Antashchuk Kseniia , Atakov Aleksey , Teremkov Andrey
Published: March 2024

The knowledge about geoelectrical structure of the area are very important for the all stages of the mineral exploration. The traditionally applied at the regional stage airborne methods, such as TEM or AEM, of course, have a lot of advantages, but their application is quite expensive. The technology of UAV based EM sounding was developed as effective tool for fast studying ore prospective area with square from the first km up to first hundred km. The technology includes the towed receiving equipment, which measures three magnetic component, the methodology of field survey implementation, the software for data processing and 1D inversion. The results of UAV based EM sounding obtained at several ore prospective sites showed their ability for geolectrical section studying in the depth range from the first up to 600 meters, faults delineating, intrusion mapping and allocation of the prospective sites. The following ground based investigations at the anomaly areas with for example IP registration allow detecting the ore zones.
 
Present geothermal field characteristics and its influencing factors in Xiong'an New Area 
Authors: Guo Sasa , Cui Yue , Tang Boning
Published: March 2024

Xiong'an New Area is located in the northern of Jizhong Depression in Bohai Bay Basin, covered by three geothermal fields: Niutuozhen, Rongcheng, and Gaoyang. Clarifying the rock physical conditions and geothermal characteristics, combined with the elements of geothermal resource accumulation (heat source, channel, reservoir, caprock, fluid), plays an important role in understanding geothermal resources.Based on heat source research, this study analyzed the temperature measurement curves of 30 drilling wells and measured data of thermal conductivity and heat generation rate of 100 rocks to analyze the geothermal gradient and distribution of geothermal flow in Xiong'an New Area. The results showed that Xiong'an New Area has a high geothermal background, with geothermal flow ranging from 53.3mW · m-2 to 106.5mW · m-2, with an average value of 73mW · m-2. It is higher than the average heat flow value of 63.0 ± 24.2mW · m-2 in China Mainland, and belongs to high abnormal area. The geothermal gradient of caprocks is around 35 ℃/km, slightly higher than that of the Mesozoic and Cenozoic fault basins in Eastern China. Based on the geothermal field, combined with the characteristics of heat sources, reservoirs, and channels of deep geothermal resources, a genetic model of geothermal resources in Xiong'an New Area is established. It is considered that the reservoir-cap assemblages composed of the Cenozoic caprocks and the Proterozoic carbonate rocks in Xiong'an New Area, the alternating structural pattern of uplift and sag, and fluid activity affect the occurrence of deep geothermal resources. The geothermal resources are prone to enrichment in uplifted structures controlled by faults or in low uplifted Proterozoic thermal reservoirs. The high-value of geothermal flow, high permeability reservoirs, and regional continuous caprocks are favorable areas for geothermal development.
Inferring soil water movement from soil moisture distribution with deep learning method
Authors: Ye Sheng , Li Jiyu , Ran Qihua
Published: March 2024

Soil moisture is an essential variable that influencing hydrological processes and water cycles within the climate system. Soil moisture movement alters the spatial and temporal distribution of soil moisture and further influences the water and heat cycle. The relationship between them is usually described by Richardson–Richards equation (RRE). However, the dual nonlinearity of this equation and the stringent requirements for initial and boundary conditions have posed challenges for the development of unsaturated soil water simulation based on the RRE. The development of machine learning brings new opportunities, yet most studies focused on the prediction of soil moisture, only a few used it to explore the underlying mechanism. Here, we implemented recurrent neural network to predict soil moisture movement at three dimensions. Soil moisture distribution at three dimensions, simulated by a physical-based hydrological model, the Integrated Hydrology model (InHM) based on RRE, was used as input, along with climate forcing as well as topographical characteristics. The model provided reasonable prediction of soil water movement at all three dimensions across the points in the study catchment. This provides a framework for an alternative way to predict soil water movement and subsurface flow path, with more field measurements, it could help us improve our understanding in subsurface water movement, providing a novel and viable solution to further promote unsaturated soil moisture simulation.
The Effects of Geographic Risk Complementarity on Reducing Flood Insurance Costs
Authors: Cui Shibo , Zhao Jianshi
Published: March 2024

Flood insurance is an important non-structural measure for flood risk management. However, a significant protection gap in flood insurance exists in many countries and the high cost of flood insurance is a primary reason. Reducing the flood insurance costs for both policyholders and insurance companies is crucial for the effective implementation of flood insurance. Here, we use portfolio theory to derive fundamental principles of reducing overall insurance cost including premiums and risk reserves through geographic risk complementarity. Furthermore, we propose a reasonable premiums distribution approach among different risk agents to analyze the effect of geographic risk complementarity on individual cost, based on the cooperative game theory. We applied our method in China, which has a large territory but lacks a national flood insurance program. We show there is a low correlation of flood losses across most provinces in China. Compared to the separate insurance in each province, national flood insurance can reduce total premiums by 14.5% and total risk reserves by 61.0%. The regions with highest proportion of premium reduction are the middle and lower Yellow River reaches, which have a lower flood risk correlation with the portfolios of other regions. In conclusion, the geographic complementarity in flood risk has a significant effect on reducing flood insurance cost and the degree of cost reduction depends on the flood risk correlation among different entities. We recommend that China should utilize the geographic risk complementarity to implement a national-level flood insurance program. The method proposed can also provide references for catastrophe insurances around the world.
Developing a global building morphology dataset for urban hydroclimate simulation
Authors: Li Ruidong , Sun Ting , Ghaffarian Saman , Tsamados Michel , Ni Guang-Heng
Published: March 2024

As prevalent infrastructures in cities, buildings play a vital role in urban hydroclimate simulation with their effects being parameterized through their 3D morphology. In order to achieve a comprehensive understanding of 3D building morphology distribution, significant efforts have been devoted to the generation of global-scale 3D building morphology datasets. However, existing works typically produce such information at a coarse resolution (around 1000 m) using either machine-learning-based regression with medium-resolution open-source satellite images or simple empirical rules with high-resolution but restricted satellite images, which limits their effectiveness in providing accurate and refined mappings for public usage and academic research. Considering this bottleneck, this work establishes a practical solution leveraging open-source Sentinel-1/2 imagery with cloud computing infrastructures and deep-learning-based models to create a dataset named GLAMOUR, which estimates the average building height and footprint at a resolution of 100 m across global urbanized areas. Based on the results of accuracy assessment in 18 cities worldwide, the GLAMOUR dataset achieves the median root mean square errors of 7.5 m for building height and 0.14 for building footprint estimation, with corresponding standard deviations of 4.0 m and 0.02, achieving better overall performance compared to existing datasets with similar spatial coverage. As a publicly accessible and reproducible dataset, GLAMOUR exemplifies the workflow of annual global monitoring of 3D building structures in urbanized areas and offers rasterized 3D building structures on 100 m grids for the year 2020 in GeoTiff format, which can be seamlessly integrated with open-source GIS software and urban hydroclimate models. With the help of GLAMOUR, researchers and policymakers can easily derive refined building-related physical parameters such as surface roughness and zero-plane displacement for urban hydroclimate simulation in their desired areas worldwide. It will facilitate a global-scale assessment of urban hydroclimate disaster risks, paving the way for holistic climate adaptation strategies.
Identification of global hotspots for salinity vulnerability
Authors: Islam Md Feroz , Snethlage Judit , Biemans Hester , Terwisscha van Scheltinga Catharien , de Miguel García Ángel
Published: March 2024

Global food security is challenged by lack of fresh water availability and increasing salinity. Water and soil salinity have increased during the last few decades and are projected to increase in the future which will adversely effect the food security. Effect of climate change will exacerbate the situation. Previous researches have predominantly focused on the impact of either soil or water salinity on agriculture and food security. An assessment of combined impact of soil and water salinity at global scale is required. We have considered global datasets on soil and water salinity to locate areas with higher impact of salinity and combined indicators on climate, water availability, source of irrigation, cropping pattern, soil characteristics and level of salinity to identify regions with higher vulnerability to salinization. The impact of salinity on crop (wheat, rice and maize) yield was considered to produce a primary estimate of potential loss of food production. Combining soil and water salinity data indicate that currently the southeast and southwest coast of USA, southern part of Africa, southeast regions of Australia and coastal regions of Bangladesh are mostly impacted by salinity.  The MENA region, sub-saharan regions, large parts of Australia, southern Europe, southwestern coast of USA, eastern China, as well as the coast of Vietnam, GCC states, the eastern part of Indonesia, northern parts of India, coastal regions of Bangladesh and southeastern regions of Africa are identified as vulnerable regions for increasing salinity. The potential crop yield loss due to salinity is highest for Maize and lowest for Wheat.  Global cropping pattern shows that rice and maize are being cultivated more in salinity vulnerable areas than wheat, even though wheat is the most saline tolerant of the three. Identification of saline hotspot areas and regions vulnerable to increasing salinity will assist in development location specific of policies, regulation and adaptation strategies to counter the adverse impact of salinity in the future. More in depth analysis on Ganges-Brahmaputra-Meghna (GBM), Mekong and Nile delta will be carried out for regional verification of salinity hotspot and vulnerable location identification.
A new deep-learning approach for the sub-pixel correlation of optical images in the near-field of earthquake ruptures
Authors: Montagnon Tristan , Giffard-Roisin Sophie , Hollingsworth James , Pathier Erwan , Dalla Mura Mauro , Marchandon Mathilde
Published: March 2024

Precise estimation of ground displacement from correlation of optical satellite images is fundamental for the study of natural disasters. In the case of earthquakes, characterizing near-field displacements around surface ruptures provides valuable constraints on the physics of earthquake slip. Recently, image correlation has been used to investigate the degree of slip localization, and how it may vary as a function of geological parameters (such as fault structural maturity), raising the possibility that slip localization (vs distribution) may be predictable, with important implications for seismic hazard assessment.Current sub-pixel correlation methods (frequency or spatial domain) all rely on the same general approach: they work at a local scale, with small sliding windows extracted from a pair of co-registered satellite images acquired at different times, and they assume a rigid uniform shift between the two correlation windows. However, in the near-field of fault ruptures, where the correlation window spans the fault discontinuity, this hypothesis breaks down, and may bias the displacements. Additional smoothing associated with the correlation window further complicates the interpretation of sharp features in the displacement field, artificially shifting displacement to the off-fault region.We developed a U-net-based method to solve the sub-pixel displacement estimation problem at a global scale. Such architecture is able to retrieve full scale surface displacement maps, making use of both global and local features, and potentially tackling different noises of the input images. We trained our model with real satellite acquisitions, warped with ultra-realistic synthetic displacement maps representing realistic faults. The model exhibits promising preliminary results, showcasing its capability to retrieve full-scale surface displacement maps with high accuracy. While direct comparisons with other state-of-the-art approaches (COSI-Corr and MicMac) are pending, our findings suggest that our proposed U-net-based approach has the potential to compete or even outperform these correlators. 
Development of low-cost technologies applied to the study of marine ecosystems.
Authors: Martinez Osuna Juan Francisco , Piermattei Viviana , De Luca Antonio
Published: March 2024

The Mediterranean Sea is a recognized area of concern considering climate change impacts. Coastal zones are particularly vulnerable to the influences of sea level variations caused by climate variability. Estuaries, which are crucial ecosystems, represent challenges areas which can be affected from various anthropogenic pressures and the effects of climate change.Within the research community, there is a growing focus on the risks associated with sea level rise (SLR). The threat of storm-related flooding poses a significant danger to coastal areas, leading to the loss of marine habitats and ecosystems. Recent experiences also have shown that the combination of high-intensity hurricanes and increased sea levels has resulted in numerous fatalities along the coast.A big lack of data and knowledge about coastal observations, particularly in developing countries, persists due to the difficulty in obtaining affordable and user-friendly instrumentation. To address these challenges, there is a need to develop cost effective, easily accessible technologies that can be integrated into different platforms. These technologies would enhance monitoring capabilities, particularly in terms of spatial resolution, along rivers and coastal zones. By doing so, we can greatly improve our understanding of storm surges, extreme events, and their impacts on transitional areas. Creating a practical tool as part of an early warning system would provide timely information on physical conditions and biological variables, aiding in effective decision-making and mitigation efforts.