bluuebunny/crossref_metadata_2025 huggingface dataset:
small-scale updrafts and snow growth in stratiform orographic clouds
Authors: Geerts Bart , Grasmick Coltin , Rauber Robert
Published: March 2020

Stratiform clouds over mountains are subject to locally strong updrafts that impact snow growth. These vertical drafts occur at a range of horizontal scales and depth, and include vertically propagating gravity waves, shallow terrain-driven (evanescent) waves, embedded convection, and shear-driven overturning cells. The latter essentially are Kelvin-Helmholtz (KH) waves; we find them to be remarkably common in deep stratiform precipitation systems associated with frontal disturbances over complex terrain, as is evident from transects of vertical velocity and 2D circulation, obtained from a 3-mm airborne Doppler radar. The high range resolution of this radar (~40 m) allows detection and depiction of KH waves in fine detail. These waves are observed in a variety of wavelengths (<100 m to > 1 km), depths, amplitudes, and turbulence intensities. Proximity rawinsonde data confirm that they are triggered in layers where the Richardson number is very small. Complex terrain may locally enhance wind shear, leading to KH instability.  In some KH waves, the flow remains mostly laminar, while in other cases it breaks down into turbulence. KH waves are frequently locked to the terrain, and occur at various heights, including within the free troposphere, at the boundary layer top, and close to the surface. They are observed not only upwind of terrain barriers, as has been documented before, but also in the wake of steep terrain, where the waves can be highly turbulent.  Doppler radar data and flight-level cloud probe data are used to explore the dynamics of KH waves and the response in terms of droplet growth, ice initiation, and snow growth.
Improving soil moisture estimation through a dual-cycle assimilation strategy
Authors: Tian Jiaxin , Qin Jun , Yang Kun
Published: March 2020

Soil moisture plays a key role in land surface processes. Both remote sensing and model simulation have their respective limitations in the estimation of soil moisture on a large spatial scale. Data assimilation is a promising way to merge remote sensing observation and land surface model (LSM), thus having a potential to acquire more accurate soil moisture. Two mainstream assimilation algorithms (variational-based and sequential-based) both need model and observation uncertainties due to their great impact on assimilation results. Besides, as far as land surface models are concerned, model parameters have a significant implication for simulation. However, how to specify these two uncertainties and parameters has been confusing for a long time. A dual-cycle assimilation algorithm, which consists of two cycles, is proposed for addressing the above issue. In the outer cycle, a cost function is constructed and minimized to estimate model parameters and uncertainties in both model and observation. In the inner cycle, a sequentially based filtering method is implemented to estimate soil moisture with the parameters and uncertainties estimated in the outer cycle. For the illustration of the effectiveness of the proposed algorithm, the Advanced Microwave Scanning Radiometer of earth Observing System (AMSR-E) brightness temperatures are assimilated into land surface model with a radiative transfer model as the observation operator in three experimental fields, including Naqu and Ngari on the Tibetan Plateau, and Coordinate Enhanced Observing (CEOP) reference site on Mongolia. The results indicate that the assimilation algorithm can significantly improve soil moisture estimation.
The Framework for Generating Climate Risk Infographic and Applying to Risk Communication
Authors: Liu Chin Chieh , Tung Ching Pin
Published: March 2020

      Adaptation is an indispensable part of climate change impact, and risk assessment plays an important role between data arrangement and strategy planning. This study aims at developing a framework from risk assessment to information presentation, then applying to risk communication. This framework refers to Climate Risk Template, defining risk as to the integration of hazard, exposure and sensitivity; simultaneously, Climate Risk Template is an auxiliary tool basing on Climate Change Adaptation Six Steps(CCA6Steps), which is the systematic procedure to analyze risk and plan adaptation pathway. This study emphasized on landslide disaster as the key issue and selected community residents, roads as the protected targets. First of all, collate stimulated results of landslide potential evaluation and literature, cases, questionnaires which were probed into exposure and sensitivity. Next, establish a factors list of climate risk and giving weights to correlation factors by Entropy Method. Finally, use risk matrix to evaluate the risk value and present the results of risk assessment by infographic. For essentially helping on risk communication, this study proposes a framework to make the general public understand the causes of regional disaster risk and assists executive units to implement climate risk assessment and adaptation pathway planning. Eventually, the study will innovate a prototype of using this framework; therefore, users just have to write down the key issue, protected target and choose the composition factors of risk, then they can accomplish climate risk assessment and generate climate risk infographic by themselves.

Keywords: Climate risk template, Climate risk assessment, Risk communication, infographic
Estimation of ground PM2.5 based on GOCI TOA reflectance using Deep Neural Network
Authors: Lee Chang Suk , Kim Sang-Min , Lee Kyung-Hwa , Yoon Jongmin , Hong Hyunkee , Choi Won Jun , Lee Dong-Won
Published: March 2020

Fine particulate matter (PM2.5), which consists of solid and liquid particles and mixture of both suspended in the near surface atmosphere, is known to be one of the most threatening elements to human health by penetrating skin, lungs and bronchi. There have been diverse studies with regard to monitoring near-surface PM2.5, particularly over East Asia, where recent rapid industrial development has produced serious air pollution. Some countries have already been operating ground-based monitoring networks and collecting relevant data. However, due to their poor spatial representativeness and inhomogeneous data quality, many of the previous studies were conducted based on space-borne observations. In this study, we tried to monitor concentrations of PM2.5, particles with aerodynamic diameters less than 2.5 µm, based on GOCI top of atmosphere reflectance using a deep neural network (DNN) method. DNN is a kind of machine learning developed from artificial neural networks. In order to enhance the model performance, near-surface atmospheric information from Unified Model was also used as input variables such as surface temperature, dew point temperature, surface pressure, height of planetary boundary layer, relative humidity and wind fields. Sensitivity examinations were conducted to find optimal structures of training models and several techniques (e.g., regularization, early stopping, and normalization of input variables) were applied to prevent over-fitting training datasets. The retrieved data were characterized by comparing with estimates from the operational MCAQ model, which is used in air quality forecasting, and conventional linear regression results.
3D mapping of Quaternary coral reef terraces on Curacao Island, Southern Carribean Sea
Authors: Cerrone Ciro , Petersen Ann-Kathrin , Stocchi Paolo , Rovere Alessio , Casella Elisa
Published: March 2020

Detailed geological field mapping is essential for the study of Relative Sea Level (RSL) indicators, that are in turn the only direct proxies to assess paleo sea level changes and long-term land movements. In the last decades, traditional mapping methods started to be complemented by small Remotely Piloted Aircraft Systems (RPAS, a.ka.a. drones) and high-resolution remote sensing datasets.

In this contribution, we show the results of geological mapping in the island of Curaçao (Netherlands Antilles). Here, we mapped a staircase sequence of coral reef terraces. In particular, we used TerraceM-2 Maptools (a Matlab® interface for mapping marine terraces) to extract wide-scale marine terrace elevations from TanDEM-X Digital Elevation Models (DEMs) (German Aerospace Center, DLR and Airbus). We detail the elevation information available for each single terrace with RPAS data processed with Agisoft Metashape, that allows obtaining as final products DEMs and orthophotos of selected sites at the inner margin of reef terraces. We then use land-based photogrammetry coupled with traditional facies analysis to identify geological discontinuities on the lower terrace.

The facies analysis allowed to precisely map the unconformity between the Hato (MIS 5.5) and Cortalein (MIS 7) Units (as identified by Muhs et al., 2012). The top of the Hato Unit forms the so-called “Curaçao Lower Terrace”. The top of the Hato Unit, extending few kilometres from the coast, has been mapped with both TanDEM-X and RPAS data up to the paleo-cliff of the Middle Terrace (formerly attributed to MIS 11), where a well-defined notch is preserved. We attribute this notch to the maximum sea ingression during MIS 5e. We compare its elevation with the RSL predicted by Glacio-Isostatic Adjustment (GIA) models.    

We discuss the new data and models for Curaçao in terms of long-term tectonic uplift and eustatic sea level.

Reference: Muhs DR, Pandolfi JM, Simmons KR, Schumann RR (2012) Sea-level history of past interglacial periods from uranium-series dating of corals, Curaçao, Leeward Antilles islands. Quat Res 78:157–169. doi: 10.1016/j.yqres.2012.05.008

Acknowledgments: TanDEM-X digital elevation data is used with permission within the Project DEM GEOL1210 (A. Rovere / M.E. Raymo). The fieldwork for this work was funded by the Helmholtz Exzellenznetzwerks “The Polar System and its Effects on the Ocean Floor (POSY)”. The authors acknowledge also the ZMT,  the Center for Tropical Marine Ecology, and the DAAD, the German Academic Exchange Service.
Contributions of soil microbes and soil organic matter to plant productivity in tropical savanna soils under different land uses
Authors: Soka Geofrey , Ritchie Mark
Published: March 2020

Arbuscular mycorrhizal fungi (AM fungi) and soil organic matter (SOM) can be important factors in soil fertility, cycling of nutrients, and plant productivity. It is still unclear whether greater AM fungi abundance is advantageous for plant productivity under nutrient-poor tropical soils despite the relatively common lack of phosphorus (P) and the purported benefit of AM fungi in obtaining and exchanging P with plants for carbon. We explored whether AM fungi and/or SOM augmented plant productivity in different field soils to test the hypotheses that AM fungi were important contributors to plant productivity and that the contribution by AM fungi is higher on soils with lower organic matter and presumably lower nutrient availability compared to soils with higher organic matter. We conducted a factorial experiment in the greenhouse with potted soils of either high or low organic matter (SOM) collected from each of three different land uses, grazed by wildlife in a protected area (Serengeti National Park, Tanzania), grazed by livestock, and cropland. Half the soils were sterilized to remove soil microbes, including AM fungi. Two grass species, Zea mays and Themeda triandra, were grown for 12 weeks in 8 replicates of each soil type and sterilization treatment. About 52.4% and 62.6% of Z. mays roots grown in non-sterilized soils were colonized by AM fungi in low and high SOM, respectively, and 38.1% and 46.7% of T. triandra roots grown in non-sterilized soils were colonized by AM fungi in low and high SOM respectively. Overall, the production of both plant species was significantly higher on control soils than sterilized soils, indicating that AM fungi likely contributed to productivity, and on soils with higher SOM. However, the separate contribution to the productivity of SOM and soil microbes varied significantly among plant species and soils from different land uses. Zea mays productivity increased most strongly to higher SOM, and declined with sterilization in agricultural, but not livestock or wildlife grazed soils. In contrast, T. triandra production was largely insensitive to SOM or sterilization except on wildlife-grazed soils, where it increased most strongly in unsterilized soils. Soil microbe impacts on productivity, therefore, may be driven more by host plant species than by lower nutrient supply, as associated with lower SOM. Furthermore, the results suggest that efforts to enhance productivity in uncultivated lands should perhaps focus on altering plant species composition, while efforts to enhance productivity in agriculture soils might not depend on beneficial soil microbes or additional fertilizer but instead on effective crop rotations to reduce soil pathogens.
Using Open Data and Citizen Science in Understanding Disaster Risk: Experience from Western parts of Nepal
Authors: Shakya Puja , Parajuli Binod Prasad
Published: March 2020

Nepal is highly vulnerable to multiple disasters due to its topography and geographic conditions. It also suffers with data deficiency in better understanding the impacts of disasters and existing capacities to cope with such disasters. This information scarcity severely hinders understanding the disasters and their associated risks in the areas. This also hampers local and regional risk reduction, preparedness and response, limiting rigorous and robust disaster risk modelling and assessment. For regions facing recurrent disaster, there is a strong need of more integrated and proactive perspective into the management of disaster risks and innovations. Recent advances on digital and spatial technologies, citizen science and open data are introducing opportunities through prompt data collection, analysis and visualization of locally relevant spatial data. These data could be used as evidence in local development planning as well as linking in different services of the areas. This will be helpful for sustained investment in disaster risk management and resilience building. In current federal structure of Nepal, there is an acute data deficiency at the local level (municipalities and wards) in terms of data about situation analysis, demographics, and statistics, disaster impacts (hazard, exposure and vulnerability) etc. This has caused hindrances to all the relevant stakeholders including government, non-government and donors in diagnosing the available resources, capacities for effective planning and managing disaster risks. In this context, we are piloting an approach to fulfil existing data gaps by mobilizing citizen science through the use of open data sources in Western Nepal. We have already tested it through trainings to the local authorities and the communities in using open data for data collection. Likewise, in one of our upcoming project on data innovations, we shall create a repository of available open data sources; develop analytical tools for risk assessment which will be able to provide climate related services. Later, upon testing the tools, these can be implemented at the local level for informed decision making.
The study of Rockfall in Keelung Mountain Area of Northeastern Taiwan
Authors: Xu Bo
Published: March 2020

This study focued on the case of rockfall in the Keelung Mountain Area in the northeastern part of Taiwan. To explore the different trajectories and range including free fall, bouncing and rolling when the rocks fall down, this research tried to analyze the local geomorphological characteristics, distribution of geological materials, and the extension of the discontinuities.

In the results, "coefficient of restitution " and "coefficient of friction" are the most important factors which affect the movement trajectory of bouncing and rolling. The coefficient of restitution is mainly affected by the three factors, such as the strength of slope surface’s material, incident angle, and collision speed. In the situation when falling rocks descend from 2m height, and setting the incident angles as 30°, 45°and 60°, we observed the coefficient of normal restitution as 0.18, 0.12, and 0.10. These results showed that, the coefficient of normal restitution of the rockfall inversely decreased with the incident angle. When fixing the incident angle at 90°, the coefficients of restitution were observed as 0.41, 0.35, and 0.31 when the rockfall from 1 m, 2 m, 3 m. This research found that the coefficient of restitution inversely decreased with the collision speed of rockfall. The size of the falling rocks which was related to the size of the block on the slope, also affected the path of the rockfall based on the bouncing movement. When the size of the rock was smaller than the size of the block at the bottom of the slope, the trajectories were influenced by undulation. When the size of the rock was larger than deposited one, the rock was hard to be affected by slope fluctuation, and continue to keep scrolling. At this situation, the movement of the rockfall was mainly affected by the coefficient of friction rather than the coefficient of restitution’s impact. The simulation is carried out using the Rocscience Rocfall program, which depicts the path and energy of rockfall, these data can be used as important reference basis of prevention of rockfall hazards.

Keywords: Rockfall, Coefficient of Restitution, Coefficient of Friction, Free Fall, Bouncing , Rolling
Interaction between the Black Carbon Aerosol Warming Effect and East Asian Monsoon
Authors: Zhuang Bingliang , Wang Tijian , Li Shu , Xie Min , Li Mengmeng , Chen Huimin , Wei Wen , Lin Huijuan
Published: March 2020

Black carbon aerosol (BC) has a significant influence on regional climate changes due to its warming effect. Such changes will feedback to BC loadings. Here, the interactions between the BC warming effect and East Asian monsoon (EAM) in both winter (EAWM) and summer (EASM) are investigated using a regional climate model RegCM4, which essentially captures the EAM features and the BC variations in China. The seasonal mean BC optical depth is 0.021 over East Asia during winter, which is 10.5% higher than that during summer. Nevertheless, the BCs direct radiative forcing is 32% stronger during summer (+1.85 W/m2). The BC direct effect would induce lower air to warm by 0.11-0.12 K, which causes an meridional circulation anomaly associated with a cyclone at 20-30 oN and southerly anomalies at 850 hPa over East Asia. Consequently, the EAM circulation is weakened during winter but enhanced during summer. Precipitation is likely increased, especially in south China during summer (by 3.73%). Compared to BC changes due to EAM interannual variations, BC changes due to its warming effect are as important, but weaker. BC surface concentrations are decreased by 1~3% during both winter and summer, by 1~3%, while the columnar BC is increased in south China during winter. During the strongest monsoon years, the BC loadings are higher at lower latitudes than those during the weakest years, resulting in more southerly meridional circulation anomalies and BC feedbacks during both winter and summer. However, the interactions between the BC warming effect and EAWM/EASM are more intense during the weakest monsoon years.
Low-frequency divergence of tree-ring d18O variations on both sides of climatic boundary mountain of eastern China since 1980s
Authors: Li Qiang , Liu Yu , Song Huiming
Published: March 2020

The Qinling Mountain is the most important mountain range in eastern China, and is the geographical boundary and the climatic boundary. We investigated tree-ring d18O variations in South and North Slope of the Qinling Mountain, and found that the variations of tree-ring  d18O were significantly correlated over the past two and a half centuries (r=0.641, n=247, p<0.001). And they are negatively correlated with relative humidity and precipitation, and positively correlated with temperature. Compared with the various hydroclimate-related time series in the surrounding area, it is found that both can represent the region's long-term hydroclimate change. The consistent changes in the interannual time scale may be due to the common modulation of ENSO. However, on the decadal time scale, there have been significant divergence between the two tree-ring  d18O series since 1981 and the divergence may be caused by changes in relative humidity at the sampling site, suggesting that in the context of global warming, although the warming range is the same, but the triggered relative humidity changes are not consistent. In addition, changes in PDO may be another cause of low-frequency difference.
The effect of the formation of the micro-terracetts on the connectivity of the sediment transport on sandy granitic soil
Authors: Onda Yuichi , Kozuka Shohei , Kato Hiroaki , Wakiyama Yoshifumi
Published: March 2020

In sandy soil, the step and mound-like formation of the erosion/ deposition structures have been reported (Ribolzi et al., 2011; Mayer et al., 2008) by visual observation or small-scale experiments though it has not been analyzed quantitively in the field. Especially no data are available on the sediment transport distance in such erosion areas. Recently, the development of Unmanned Aerial Vehicle based Structure from Motion (UAV-SfM) technique can provide the hi-resolution and hi-accuracy topographic data. This study aimed to detect the step-like erosion and deposition and discuss the step-like erosion and deposition process.

 Our study site was located in Yamakiya district, Fukushima, Japan. This area was decontaminated in 2014 by the Ministry of Environment to reduce the air dose rate by removing topsoil and overlaying decomposed granite soil (organic matter: 4.6%, sand: 68.8%, silt: 19.7%, clay: 6.9%, measured on 10/10/2019). We installed a USLE soil erosion plot (5 m wide and 21 m long) on the farmland slope. The topography in the plot was measured by the UAV-SfM method. UAV used in this study was Phantom4 Pro and flying height was 5 – 10 m. 200 – 400 photos were taken for each survey. Photos were imported to Photoscan, and 3D point clouds were reconstructed. 3D point clouds were imported to ArcGIS pro and converted to DSM data. Finally, soil surface changes were calculated for each survey period. Transport distances of soil particles were measured by RFID tags. RFID tags were coated with cement, bronze powder, fluorescent paint, and topcoat and had 3 – 5 mm size and 2.0 – 3.0 g cm-3 density. 100 RFID tags were set to the soil surface.

 Step-like erosion and deposition were observed between 8/28/2019 – 10/16/2019. Soil surface change in this period showed that erosion and deposition were repeated and higher erosion on the lower slope position. Topography data also showed steeper step structures in the eroded area than the depositional area. Median transport distance of RFID tags in the interrill areas is 4.1 cm, and 76 cm in the terracet areas. Therefore, we found the effect of soil mounds and the terracettes on the bare soil connectivity significantly increase the sediment connectivity and sediment transport distance.
Post-fire regeneration strategies contribute to plant growth dynamics and habitat selection in subtropical monsoon fire-prone ecosystem
Authors: Luo Caifang , Li Yiying , Yang Kang , Han Jie , Jiang Youxu , Shen Zehao
Published: March 2020

In fire-prone ecosystems subjected to frequent fires, trees species with different post-fire regeneration strategies (PFRS) coexist at local scale. Different growth dynamics and habitat selection of species account for their coexistence. To explore how much variety is decided by the PFRS, we selected four co-occurring tree species including one Facultative seeders (FS) species and three obligate resprouters (OR) species, conducted a field investigation to measure growth dynamics at sites with different time since last fire (TSF) and recorded its living environment information in Central Yunnan Plateau. We also measured the burl size of OR species to subclassify PFRS into obligate resprouters-resprouts number (OR-N) and obligate resprouters-resprouts height (OR-H) by the growth priority to quantity or height. Generally, FS and OR species exhibited different seedlings clump density and height growth rate (HGR) and showed different temporal dynamics. OR-N species occupied post-fire gaps with rapid canopy growth and were more predominant than OR-H species and FS species at the early period of post-fire regeneration, while OR-H species had the highest HGR. However, such difference was not well explained by environmental factors (R2 < 20%) except seedlings growth rate, while explanation increased when subclassfication was considered as random factor in linear mixed models (LMMs). Moreover, species habitat selection was also associated tightly with regeneration strategies. The result of Redundancy Analysis (RDA) indicated that Pinus (FS) dominated on sunny slope was consistent with gap-dependence model and environment-variability model, and Cyclobalanopsi (OR-H) are favored in the fertile sites that can facilitate its height growth. Resprouters species Lithocarpus which prefer growing on sunny slope in unburned areas but showed preference on shade slope in post-fire regeneration. Therefore, the impacts of regeneration strategies caused some species shift their normal distribution ranges after fire. In conclusion, different growth dynamics and habitat selection of the four tree species during the post-fire regeneration enable their coexistence. Our study provides a novel perspective that by using subclassification of regeneration strategies, the prediction power of species performance and niche partitioning can significantly increased.
Provenance of sediments in the western Sea of Japan over the last 30 ka: Implications for paleoenvironmental changes
Authors: Dou Ruxi , Zou Jianjun , Shi Xuefa , Zhu Aimei , Dong Zhi , Shi Fengdeng , Xue Xinru , Gorbarenko Sergey
Published: March 2020

The Sea of Japan is a unique marginal sea in the northwest Pacific Ocean, which is known as "miniature ocean". Constrained by four shallow straits communicating with surroundings seas, it is very sensitive to glacio-eustatic sea level changes. Also, it is located beneath the East Asia Monsoon, which affects the hydrography of surface waters, deep circulations and accumulation of terrigenous materials. The presence of seasonal ice also plays a role in controlling the local distributions of terrigenous materials and deep ventilation in the Sea of Japan. An increasing body of studies revealed pronounced changes in past ocean environment in the Sea of Japan since the late Quaternary. However, it remains elusive for past environment changes in the western Sea of Japan. In this study, we investigate the lithology, rare earth elements and radiogenic isotopes of sediment core LV53-18 retrieved from the western Sea of Japan since the last glaciation.

The contents of coarse fraction of sediment grain size suggest an advance in sea ice cover during the last deglaciation and the early Holocene (15-8 ka) and potential perennial sea ice cover during Heinrich Stadial (HS) 1 and HS2. The variation in sea ice cover is explained by changing strength of East Asian Winter Monsoon (EAWM). On millennial timescales (HS2, HS1 and Younger Dryas), our grainsize data shows a reverse correlation between the EAWM and the East Asian Summer Monsoon (EASM), indicating by Chinese stalagmite δ18O record, and it is ascribed to the slowdown of Atlantic Meridional Overturning Circulation (AMOC). The brine rejection related to sea-ice generation enhances local deep ventilation.

Both the concentration of ∑REEs and positive Eu anomaly (1.2~1.4) reveal a sustained contribution of calcium-rich volcanic materials after 8 ka, which coincides with the onset and intensity of Liman Cold Current during the sea-level highstand. Furthermore, the 87Sr/86Sr values (0.706347 to 0.711713) decrease after 8 ka while εNd (-5.09 to -2.45) are more radiogenic, which further corroborate the presence of volcanic materials. On the basis of a binary mixture of volcanic material and upper crust, we estimated qualitatively the relative contributions of these two end-members. In summary, our study underlines the importance of EAWM in controlling the environment in the western Sea of Japan and reveals increasing volcanic contribution since 8 ka, which is related to the intensity of Liman Cold Current.

Note: This study was supported by the National Natural Science Foundation of China (Grant No. 41420104005, U1606401) and National Program on Global Change and Air-Sea Interaction (GASI-GEOGE-04).
Daily Precipitation Threshold for Rainstorm and Flood Disaster in the Mainland of China: An Economic Loss Perspective
Authors: Liu Wenhui , Wu Jidong , Tang Rumei , Ye Mengqi , Yang Jing
Published: March 2020

Exploring precipitation threshold from an economic loss perspective is critical for rainstorm and ﬂood disaster risk assessment under climate change. Based on the daily gridded precipitation dataset and direct economic losses (DELs) of rainstorm and ﬂood disasters in the mainland of China, this paper ﬁrst ﬁltered a relatively reasonable disaster-triggering daily precipitation threshold (DDPT) combination according to the relationship between extreme precipitation days and direct economic loss (DEL) rates at province level and then comprehensively analyzed the spatial landscape of DDPT across China. The results show that (1) the daily precipitation determined by the combination of a 10 mm ﬁxed threshold and 99.3th percentile is recognized as the optimal DDPT of rainstorm and ﬂood disasters, and the correlation coeﬃcient between annual extreme precipitation days and DEL rates reached 0.45 (p < 0.01). (2) The optimal DDPT decreases from southeast (up to 87 mm) to northwest (10 mm) across China, and the DDPTs of 7 out of 31 provinces are lower than 25 mm, while 5 provinces are higher than 50 mm on average. These results suggest that DDPTs exist with large spatial heterogeneity across China, and adopting regional diﬀerentiated DDPT is helpful for conducting eﬀective disaster risk analysis.
The impact of interpolation method on the accuracy of meteorological variables in distributed hydrological model
Authors: Liu Jiajia , Zhou Zuhao , Yan Ziqi , Jia Yangwen , Wang Hao
Published: March 2020

Precipitation and other meteorological variables are very important input data for distributed hydrological models, which determine the simulation accuracy of the models. It is a normal way to subdivide the large area watershed into numerous subbasins to reflect the spatial variation, and the value is usually unique within each subbasin. In most model application, the values of meteorological variables are interpolated from meteorological station observed data to the centroid point of the subbasin with interpolation method (called one-cell interpolation). Because the centroid point could not represent the whole subbasin, the one-cell interpolation will bring input data uncertainty to the model. In this study, a new method is introduced to analysis this uncertainty, which firstly interpolate the values into numerous cells smaller than the subbasin then sum up to the subbasin (called multi-cells interpolation). The results show that one-cell interpolation way is not always consistent with the results of multi-cells interpolation, and the variance is greater in summer than in winter. The consistency grows with the increase of the number of the cells, which indicates that dozens of the cells could got the stable state. The variance is also influenced by the density of meteorological station, but the minimal cell number is almost the same. Thus, in the interpolation of the meteorological variables in distributed hydrological model, it recommends to interpolate the values to numerous smaller cells then sum up to the subbasins, rather than only interpolate to the centroid point.
Air pollutant dispersion altered by urban-rural breeze and urban sprawl
Authors: Chen Yung-Chang , Hwang Gong-Do , Chen Wei-Nai , Chou C.-K. Charles
Published: March 2020

Air pollution becomes a serious issue due to the population growing up and residential area sprawl in decades. Residential area is not only a major source of air pollutants but also an impact to generate an urban-rural thermal wind and to alter the dispersion of air pollutants. However, the urban-rural breeze caused by a metropolitan is not the only impact on the dispersion of air pollutants. Generally, a synoptic weather condition is the major impact to dominate how the air pollutant exactly diffuses. The most metropolitans are located in the coastal regions. Therefore, a naturally thermal wind, sea-land-breeze, plays also commonly an essential role to transfer the air pollutant. Additionally, topography and natural obstacle are unable to be ignored as an impact to obstruct flow streaming which brings the air pollutant away.

Overall, synoptic weather conditions, local sea-land-breeze patterns, and natural obstacles are three major natural impactors to influence air pollutant dispersion. The urban-rural-breeze pattern and the roughness of the urban area are regarded as the two anthropogenic factors to alter the large breeze system and thereby affecting the spreading pathway of the air pollutant. To analysis the interaction of above mentioned five impactors could be regarded as a comprehensive approach to consider how the air pollutant transfer from a metropolitan to air pollution suffering areas.

In this study, we apply either computational or measurement tools to consider the effects of metropolitan, Taichung, which is located in middle Taiwan, in the heat island effect and modification of the roughness to alter the natural breeze and also the dispersion of the air pollutant. Several intensive observation periods of 3-dimensional wind field network in boundary layer have been proposed as the evidences to discuss the impacts of urban sprawl on the breeze circulation in Taichung. Otherwise, a large-eddy-simulation model, Parallel-Large-Eddy-Simulation Model (PALM) is applied in the study initially to realize the influence of synoptic weather conditions and topography on air pollutant dispersion. Thereafter, the impacts of the heat fluxes and the roughness changing due to the urban sprawl are proposed in the study. Overall, the altering of metropolitan on the natural breeze is a slight but significant impact and could change the air pollutant dispersion.

 

Key Words: Boundary Layer, Wind field, Large-Eddy-Simulation, PALM, Urban Sprawl, Heat Island Effect, Thermal Wind
Mechanisms controlling the chemical weathering flux and CO2 consumption rate of Cauvery river, South India: Role of secondary soil minerals (in weathered profiles) versus primary minerals and anthropogenic sources
Authors: Upendra Badimela , Manohar Ciba , Aji Aiswarya , Vasudevan Vinu Dev , Krishnan Anoop Krishnan
Published: March 2020

Abstract
Hydrochemical assessment have been carried out for a tropical, east flowing Western Ghats river Cauvery, southern India, to understand the dissolved load sources, acquisition processes and their controlling factors. Silicate weathering rates (SWR) and associated CO2 consumption rates (CCR) are estimated along with quantification of source wise solute load contribution towards total solute load of the Cauvery River Basin (CRB). Atmospheric input, anthropogenic activities and water-mineral interaction processes are identified as the major solute sources. Using the chemical mass balance forward model, source wise solute load contributions are estimated to be 13%, 32%, 47% and 8% from atmospheric input, anthropogenic activities, silicates and carbonates weathering respectively. It’s found that, chemical weathering followed by anthropogenic activities are the controlling factors for the solute load of CRB with minor influence of atmospheric input. Weathering index calculated for CRB (Re > 3), suggest incomplete weathering of drainage rocks resulting in formation of secondary soil minerals along the river course. Further, detailed analysis of chemical weathering mechanisms is accomplished via end-member mixing analysis approach (EMMA) by using Ca/Na and Mg/Na ratios of different end-members including primary minerals form country rocks and secondary soil (weathered profile) minerals. End-member mixing diagram referred as modified Na-normalized Ca versus Mg, reveal that chemical weathering of secondary soil minerals is as significant as primary minerals and source wise solute load contribution to the river is almost equal from both sources primary and secondary. At outlet of the basin (Musiri), SWR and associated CCR values are estimated to be 12.9 t.km-2.y-1 and 3.3 × 105 mole.km-2.y-1 respectively. Results indicate that average SWR values estimated for the east flowing Cauvery river are several times (~ 4) lower than the average SWR values of west flowing Western Ghats rivers, even though the associated CO2 consummation rates are comparable for both river systems.
Keywords: Cauvery river, solute acquisition mechanisms, chemical weathering, anthropogenic sources, primary minerals, secondary soil minerals, silicate weathering, CO2 consumption rates.
Season-dependent predictability and error growth dynamics for La Nina predictions
Authors: Hu Junya , Duan Wansuo , Zhou Qian
Published: March 2020

The “spring predictability barrier” (SPB) is a well-known characteristic of ENSO prediction, which has been widely studied for El Niño events. However, due to the nonlinearity of the coupled ocean–atmosphere system and the asymmetries between El Niño and La Niña, it is worthy to investigate the SPB for La Niña events and reveal their differences with El Niño. This study investigates the season-dependent predictability of sea surface temperature (SST) for La Niña events by exploring initial error growth in a perfect model scenario within the Community Earth System Model. The results show that for the prediction through the spring season, the prediction errors caused by initial errors have a season-dependent evolution and induce an SPB for La Niña events. Two types of initial errors that often yield the SPB phenomenon are identified: the first are type-1 initial errors showing positive SST errors in the central-eastern equatorial Pacific accompanied by a large positive error in the upper layers of the eastern equatorial Pacific. The second are type-2 errors presenting an SST pattern with positive errors in the southeastern equatorial Pacific and a west–east dipole pattern in the subsurface ocean. The type-1 errors exhibit an evolving mode similar to the growth phase of an El Niño-like event, while the type-2 initially experience a La Niña-like decay and then a transition to the growth phase of an El Niño-like event. Both types of initial errors cause positive prediction errors for Niño3 SST and under-predict the corresponding La Niña events. The resultant prediction errors of type-1 errors are owing to the growth of the initial errors in the upper layers of the eastern equatorial Pacific. For the type-2 errors, the prediction errors originate from the initial errors in the subsurface layers of the western equatorial Pacific. These two regions may represent the sensitive areas of targeted observation for La Niña prediction. In addition, the type-2 errors in the equatorial regions are enlarged by the recharge process from 10°N in the central Pacific during the eastward propagation. Therefore, the off-equatorial regions around 10°N in the central Pacific may represent another sensitive area of La Niña prediction. Additional observations may be prioritized in these identified sensitive areas to better predict La Niña events.
The break-up of the Indian subcontinent from Gondwana: constrain by detrital zircon U-Pb dating of mid- Paleozoic-early Cenozoic strata in eastern Nepal
Authors: Baral Upendra , Lin Ding
Published: March 2020

The rifting and the amalgamation of earth landmass is a continuous process. The assembly of the Gondwana lasted from ~730 Ma to 500 Ma, and most of the mass is covered by glaciation at the southern hemisphere. Afterthought experienced multiple episodes of rifting and collision of small ribbon shape microcontinents. The extra-peninsular Gondwana sequence is discontinuous in the Himalayan orogenic belt while peninsular Gondwana sequence is broadly distributed in numerous intracratonic basins of peninsular India. The detrital zircon U-Pb ages from Permo-Carboniferous sequence peak at ~1164 with a subordinate peak at ~1305 Ma. This result emphasised that the sediments were mainly sourced from the Stenian magmatism in Albany-Fraser orogeny or the East Africa-Nibua and eastern coast of India, and southwest Australia. Also, the unit also contains sporadic volcanic unit (Baraha Volcanics). The Saptakoshi Formation, uncomfortably overlain the Khokha Diamictite, yield the peaks at ~522 Ma and 941 Ma with a younger peak at ~113 Ma with some older peaks at ~1811 and 1917 Ma. This younger detritus possibly sourced from the Rajhmahal basalt ~~115-120 Ma) while the remaining grains show a similar trend to the underlying Diamictite and overlying Tamrang Formation. Additionally, the Tamrang Formation have peaks at ~976 Ma, and 1716 Ma, identically identical to the Greater Himalayan sequence. The U-Pb age distribution of these three units coincide with the Tethys Himalaya further brings the possibility that either they share the same provenance or recycled from the Tethys Himalaya till Permian and onwards there was input from the Lhasa terrane, South Qiangtang terrane, and Indo China blocks.
Pollution trace gas distributions in the Asian monsoon UTLS derived from measurements of the airborne imaging limb sounder GLORIA during the StratoClim campaign
Authors: Johansson Sören , Höpfner Michael , Friedl-Vallon Felix , Ungermann Jörn , Kirner Oliver , Bucci Silvia , Legras Bernard , Wohltmann Ingo , Wetzel Gerald , Glatthor Norbert , Kretschmer Erik
Published: March 2020

We will present trace gas measurements obtained by the airborne imaging limb sounder GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) instrument that has been operated on the Geophysica research aircraft in area of the Indian subcontinent with basis in Kathmandu, Nepal during the StratoClim campaign in July/August 2017.
We will show retrievals of two-dimensional trace-gas distributions derived from GLORIA observations in the UTLS (Upper Troposphere Lower Stratosphere) region during the Asian monsoon. Targeted gases are, amongst others, O3, HNO3, PAN, C2H2, and HCOOH. We will present an analysis of retrieval performance including diagnostics of spatial resolution and an estimated error budget.
In our contribution, we compare these GLORIA measurements with results of the atmospheric models EMAC (ECHAM/MESSy Atmospheric Chemistry) and CAMS (Copernicus Atmosphere Monitoring Service) reanalysis and discuss the influence of non-methane volatile organic compound emissions by sensitivity simulations with the EMAC model. Using trajectories from the models ATLAS and TRACZILLA, measured pollution trace gas plumes are connected to possible sources of origin. Due to the high convective activity in the region of the Asian monsoon, both trajectory sets consider vertical transport by convection, however in a different manner.
We show that there are very delicate structures of pollutant trace gases in the Asian monsoon UTLS, and that atmospheric models have difficulties in reproducing these structures, which is likely to be caused by insufficient vertical transport from convection in meteorological fields or by missing sources in the emission inventories used by the models.
Responses of chemical weathering and gully erosion causing land degradation in the extended part of Chotanagpur plateau in India
Authors: Chandra Pal Subodh , Chakrabortty Rabin
Published: March 2020

Whether the hot and humid subtropical plateau region could leads to land degradation in the form of weathering and gully erosion. In this study, chemical weathering, gully erosion and cohesiveness are investigated together to bring out a new comprehensive idea with a view to understand their controlling factors. This study aimed to address potential land degradation in the extended part of Chotanagpur plateau region. The layers of controlling factors of gully erosion were developed and prioritized considering advanced decision tree, decision tree and random forest algorithms in the R software and the results of these methods were also validated using receiver operating characteristic (ROC) curves. Degree of chemical weathering and cohesiveness were measured through the chemical, physical and spectroscopic analysis of the randomly collected 412 soil samples. Apart from this, the climatic elements like temperature and rainfall were considered for estimating the chemical weathering. The results of the gully erosion models have superb accuracy, i.e. ROC values were 0.970, 0.960 and 0.955 respectively. Therefore, advanced decision tree model has been integrated with the results of degree of chemical weathering and cohesiveness in GIS platform end eventually the land degradation map has been developed. The land degradation map shown that 15% of the study area is highly affected by land degradation whereas 18% area is moderately affected by land degradation and rest of the 67% area is less affected by land degradation. This study provides essential information to the policy makers in order to taking decision for minimizing and controlling the land degradation. This innovative comprehensive approach is significant to assess degradation of existing land to a large scale.

Keywords: Land degradation; weathering; cohesiveness; gully erosion; spectroscopic analysis
Examining Climate Justice with Regional Disaster Resilience
Authors: Chen Yi Shiuan
Published: March 2020

     "Climate Justice" explains "climate change as the source of a double inequality with an inverse distribution of risk and responsibility around the regions.” It is also represents a “disproportionate disaster risk burden” between regions, and focus on the limit of the living conditions in climate change. Recently, the issue of "climate justice" has been highly valued internationally. Before the start of the “United Nations Climate Change Conference”(COP24) in 2018, there were 130 countries and 403 nonprofit organization signed a statement and required that all governments needed to pay attention to climate justice and should include in “Paris Agreetment”.
     In recent years, there has been a correlation between climate justice research and “disaster resilience”, but it can be found that the research of climate justice is not much different from the general disaster resilience research, and the analysis of the research is less included in the inequality of climate justice. In addition, the meanings and theories of "climate justice" have not been systematically generalized in the past literature.
Therefore, in addition to thoroughly understanding the theory and contents of "climate justice" this research will identify areas with "climate injustice" characteristics through quantitative research methods (Spatial Autocorrelation e.g.). Besides, climate change is a " long-term impact ", it is not easy to calculate from a single timing, so this research will join the time factors to analyze the "time lag effect."  
     This research will choose Taiwan as the research area and focus on flooding data because of the unfairness between water management budget and the flooding condition of the extreme rainfall. Then the above research results will be incorporated into the “Climate Justice ” theory as a basis for diagnosing regional disaster resilience and give advice on policy and planning in response to climate justice.