Traceability Model Design and Validation for Precipitation Radar

Abstract: The propagating process of data chain of a large instrument is usually indicated by the traceability model. In this paper, to enhance the measurement accuracy of the precipitation radar, we proposed a traceability mode design scheme for the power measurement internal the precipitation radar, which is the key parameter relating to the precipitation measurement. Unlike the conventional internal calibration, we design three additional circuits, including temperature compensation, sectional amplification, auto-calibration power source, according to the traceability model. By introducing three internal detection points, the online soft-calibration data package is obtained by using internal power meters and the environmental sensors. According to the measured power information and the temperature information, the calibration data package provides the online calibration and the attenuation control. Practical internal calibration and real-time online measurement experiments are conducted to validate the design scheme. The experimental results reveal the traceability model design and corresponding soft calibration strategy can improve the reliability of the dynamical measurement data and the dynamical performance of the radar measurement

Traceability Model Design and Validation for Precipitation Radar

The propagating process of data chain of a large instrument is usually indicated by the traceability model. In this paper, to enhance the measurement accuracy of the precipitation radar, we proposed a traceability mode design scheme for the power measurement internal the precipitation radar, which is the key parameter relating to the precipitation measurement. Unlike the conventional internal calibration, we design three additional circuits, including temperature compensation, sectional amplification, auto-calibration power source, according to the traceability model. By introducing three internal detection points, the online soft-calibration data package is obtained by using internal power meters and the environmental sensors. According to the measured power information and the temperature information, the calibration data package provides the online calibration and the attenuation control. Practical internal calibration and real-time online measurement experiments are conducted to validate the design scheme. The experimental results reveal the traceability model design and corresponding soft calibration strategy can improve the reliability of the dynamical measurement data and the dynamical performance of the radar measurement

Effects of Leaf Size and Defensive Traits on the Contribution of Soil Fauna to Litter Decomposition

International audienceLeaf litter quality has been acknowledged as a crucial determinant affecting litter decomposition on broad spatial scales. However, the extent of the contribution of soil fauna to litter decomposability remains largely uncertain. Nor are the effects of leaf size and defensive traits on soil fauna regulating litter decomposability clear when compared to economics traits. Here, we performed a meta-analysis of 81 published articles on litterbag experiments to quantitatively evaluate the response ratio of soil fauna to litter decomposition at the global level. Our results revealed that soil fauna significantly affected litter mass loss across diverse climates, ecosystems, soil types, litter species, and decomposition stages. We observed significantly positive correlations between the response ratio of soil fauna and leaf length, width, and area, whereas the concentrations of cellulose, hemicellulose, total phenols, and condensed tannins were negatively correlated. Regarding economic traits, the response ratio of soil fauna showed no relationship with carbon and nitrogen concentrations but exhibited positive associations with phosphorus concentration and specific leaf area. The mean annual temperature and precipitation, and their interactions were identified as significant moderators of the effects of soil fauna on litter decomposition. We evidenced that the contribution of soil fauna to litter decomposability is expected to be crucial under climate change, and that trait trade-off strategies should be considered in modulating litter decomposition by soil fauna

Phenotypic Plasticity and Local Adaptation of Leaf Cuticular Waxes Favor Perennial Alpine Herbs under Climate Change

Six perennial herbs (Plantago asiatica, Polygonum viviparum, Anaphalis lactea, Kobresia humilis, Leontopodium nanum and Potentilla chinensis) widely distributed in alpine meadows were reciprocally transplanted at two sites in eastern edge of Qinghai-Tibetan Plateau, Hongyuan (3434 m, 2.97 °C, 911 mm) and Qilian (3701 m, 2.52 °C, 472 mm), aiming to evaluate the responses of alpine plants to changing environments. When plants were transplanted from Hongyuan to Qilian, most plant species showed a decrease of total wax coverage in first year and reverse trend was observed for some plant species in second year. However, when plants were transplanted from Qilian to Hongyuan, the response of total wax coverage differed greatly between plant species. When compared with those in first year, plasticity index of average chain length of alkane decreased whereas carbon preference index of alkane increased at both Hongyuan and Qilian in second year. The total wax coverage differed between local and transplanted plants, suggesting both environmental and genetic factors controlled the wax depositions. Structural equation modeling indicated that co-variations existed between leaf cuticular waxes and leaf functional traits. These results suggest that alpine herbs adjust both wax depositions and chain length distributions to adapt to changing environment, showing climate adaptations

Climate and litter traits affect the response of litter decomposition to soil fauna

International audienceObjectives Soil fauna plays a crucial role in contributing to litter breakdown, accelerating the decomposition rate and enhancing the biogeochemical cycle in terrestrial ecosystems. Comprehending the specific fauna role of functional species in litter decomposition is challenging due to their vast numbers and diversity. Climate and litter quality are widely acknowledged as dominant drives of litter decomposition across large spatial scales. However, the pattern of climate and litter quality modulates the effect of soil fauna on litter decomposition remains largely unexplored. To address this gap, we conducted an extensive analysis using data from 81 studies to investigate how climate and litter traits affects soil fauna in the decomposition. Data description The paper describes fauna body size, climate zones (tropical, subtropical and temperate), ecosystem types (forest, grassland, wetland and farmland), soil types (sand, loam and clay), decomposed duration ( 360 days), litter initial traits, average annual temperature and precipitation. The litter traits encompass various parameters such as concentrations of carbon, nitrogen, phosphorus, potassium, lignin, cellulose, total phenol, condensed tannin, hydrolysable tannin and other nutrient traits. These comprehensive datasets provide valuable insights into the role of soil fauna on the decomposition at global scale. Furthermore, the data will give researchers keys to assess how climate, litter quality and soil fauna interact to determine decomposition rates

Effects of fertilizations on soil bacteria and fungi communities in a degraded arid steppe revealed by high through-put sequencing

Background Fertilization as one of the measures in restoring degraded soil qualities has been introduced on arid steppes in recent decades. However, the fertilization use efficiency on arid steppes varies greatly between steppe types and years, enhancing uncertainties and risks in introducing fertilizations on such natural system to restore degraded steppes. Methods The experiment was a completely randomized design with five fertilization treatments, 0 (Control), 60 kg P ha−1 (P), 100 kg N ha−1 (N), 100 kg N ha−1 plus 60 kg P ha−1 (NP), and 4,000 kg sheep manure ha−1 (M, equaling 16.4 kg P ha−1 and 81.2 kg N ha−1). Soils were sampled from a degraded arid steppe which was consecutively applied with organic and inorganic fertilizers for three years. We analyzed the diversity and abundance of soil bacteria and fungi using high-throughput sequencing technique, measured the aboveground biomass, the soil chemical properties (organic carbon, available and total phosphorus, available and total nitrogen, and pH), and the microbial biomass nitrogen and microbial biomass carbon. Results In total 3,927 OTU (operational taxonomic units) for bacteria and 453 OTU for fungi were identified from the tested soils. The Ace and Chao of bacteria were all larger than 2,400, which were almost 10 times of those of fungi. Fertilizations had no significant influence on the richness and diversity of the bacteria and fungi. However, the abundance of individual bacterial or fungi phylum or species was sensitive to fertilizations. Fertilization, particularly the phosphorus fertilizer, influenced more on the abundance of the AMF species and colonization. Among the soil properties, soil pH was one of the most important soil properties influencing the abundance of soil bacteria and fungi. Discussion Positive relationships between the abundance of bacteria and fungi and the soil chemical properties suggested that soil bacteria and fungi communities in degraded steppes could be altered by improving the soil chemical properties through fertilizations. However, it is still not clear whether the alteration of the soil microbe community is detrimental or beneficial to the degraded arid steppes

Arbuscular Mycorrhiza Fungi Strengthen the Beneficial Effects of Warming on the Growth of Gynaephora Menyuanensis Larvae

 Herbivores experience an unprecedented variously impacts of climate warming. Besides, arbuscular mycorrhiza fungi (AMF) also is influence on herbivores through their common host plants. Surprisingly, there are no reports about how AMF affect the responses of herbivores to warming. To close this gap, we conducted a two factors experiment to research the effects of warming, fungicide (AMF suppression), and their interaction on the development of Gynaephora menyuanensis larvae, an endemic generalist herbivore species in northeastern Tibetan Plateau, and nitrogen content of Elymus nutans, which was the main food of G. menyuanensis. Warming significantly advanced the pupation time (PT), expanded the phenomena of protandry and increased the growth rate (GR) of G. menyuanensis larvae. Fungicide not affected the development of G. menyuanensis larvae, despite their negative effects on the content of E. nutans. Warming with fungicide decreased the GR of G. menyuanensis compared with warming treatment. In other words, AMF strengthen the beneficial effects of warming to G. menyuanensis. This study provides the first evidence of the impacts of AMF on the response of herbivore to warming

Community characteristics of macroinvertebrates in woody debris in a subtropical forest in Badagongshan, China: A case study on three tree species and two debris diameter classes

International audienceAims: Woody debris provides essential habitat and food resources for macroinvertebrate communities and greatly impacts soil macrofauna biodiversity. Little is known about how features of woody debris are associated with soil macroinvertebrate communities, especially for subtropical forests. This study aims to investigate the effects of tree species, diameter classes, and decomposition stages of woody debris on the composition and structure of macroinvertebrate communities. Method: We sampled the woody debris of three tree species (Sassafras tzumu, Fagus lucida, and Cryptomeria fortunei), crossed with two size classes (10 ± 2 cm and 4 ± 2 cm in diameter) at different decomposition stages in the subtropical forests of the Badagongshan National Nature Reserve, Hunan, China, from October to November 2020. Then, macroinvertebrates in the sampled woody debris (i.e., taxonomical groups and number of individual) were inventoried for community feature characterization. Results: (1) A total number of 2,558 individuals belonging to 4 phyla, 10 classes, and 23 orders were found throughout the study. The dominant groups, common groups, and rare groups of macroinvertebrates differed in preferred tree species. (2) The individual density of macroinvertebrates in the woody debris of F. lucida was significantly higher than that in C. fortunei and S. tzumu. For F. lucida and S. tzumu, the Shannon-Wiener diversity index of macroinvertebrates was significantly higher in large-diameter woody debris than that in small-diameter debris. The number of total groups and specialist groups of invertebrates in large-diameter wood debris were more than those in small-diameter woody debris. The Shannon-Wiener diversity index, Simpson index, and Pielou index of macroinvertebrates in woody debris were significantly and negatively correlated with wood density, indicating shifted macroinvertebrates communities in woody debris with the progress of decomposition. (3) The physical and chemical properties of woody debris (e.g., relative moisture content, total nitrogen, total carbon, and carbon nitrogen ratio), soil temperature and soil humidity were significantly correlated with the characteristics of macroinvertebrate communities in woody debris. Conclusion: Our results highlight that the characteristics of macroinvertebrate community are different depending on the effect of tree species, diameter classes, and decomposition stages of woody debris. Preserving woody debris of both large and small diameter classes and those of different tree species in the subtropical forest can increase the biodiversity of macroinvertebrate

Effects of nutrient addition on degraded alpine grasslands of the Qinghai-Tibetan Plateau: A meta-analysis

International audienceClimate warming and human disturbance are supposed to have severely affected the alpine grasslands on the Qinghai-Tibetan Plateau (QTP), a region where the extremely harsh and fragile ecological environment has attracted great attention because of its sensitivity to global change. However, there is still no unified understanding of the degree and magnitude of grassland degradation and the effectiveness of nutrient addition in this vast landscape, since most previous studies have focused on short-term observations at a single site. Here, we conducted a meta-analysis of 145 published studies on degraded alpine grassland along with 90 published studies, which concerning nutrient addition (nitrogen [N], phosphorus [P], and combined N and P [NP]) to quantitatively assess the responses of plant and soil characteristics to land degradation and restoration. Our results revealed that the response ratio (RR) of above-ground biomass (AGB), below-ground biomass (BGB), soil organic carbon (SOC), and soil total N (TN) decreased significantly (−47.23 %, −43.45 %, −32.35 %, and −37.97 %, respectively) in degraded grassland compared with non-degraded grassland. The RR of AGB was correlated with mean annual precipitation (MAP), while the RR of BGB was correlated with the interaction of MAP and mean annual temperature (MAT). Severely degraded grassland required additional nutrients to aid recovery. NP addition to severely degraded sites increased plant AGB (+32.44 %), TN (+10.99 %), soil total P (+32.25 %), and soil moisture (+9.21 %), but significantly decreased species richness (−45.46 %), diversity (−30.40 % for Shannon−Wiener index) and soil pH (−3.91 %). N addition increased the RR of AGB and grass biomass significantly by 28.77 % and 36.49 %, but had no significant effect on sedge and forb biomass. MAP influenced the RR of AGB, TN, TP under NP addition, the RR of BGB and the AGB of different function groups were significantly affected by MAT. We evidenced that the QTP has endured severe vegetation and soil degradation, which cannot be completely mitigated by supplementary fertilisation. Fertilisation could yield positive effects on plant performance and soil quality, but negative effects on biodiversity. Climate warming and associated precipitation change may regulate the effects of fertiliser on plant biomass and soil nutrients